| /* |
| * |
| * Connection Manager |
| * |
| * Copyright (C) 2007-2014 Intel Corporation. All rights reserved. |
| * Copyright (C) 2022 Matthias Gerstner of SUSE. All rights reserved. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
| * |
| */ |
| |
| #ifdef HAVE_CONFIG_H |
| #include <config.h> |
| #endif |
| |
| #include <errno.h> |
| #include <stdlib.h> |
| #include <unistd.h> |
| #include <string.h> |
| #include <stdint.h> |
| #include <arpa/inet.h> |
| #include <netinet/in.h> |
| #include <sys/types.h> |
| #include <sys/socket.h> |
| #include <fcntl.h> |
| #include <netdb.h> |
| #include <resolv.h> |
| #include <gweb/gresolv.h> |
| |
| #include <glib.h> |
| |
| #include "connman.h" |
| |
| #ifdef DNSPROXY_DEBUG |
| # define debug(fmt...) do { fprintf(stderr, fmt); fprintf(stderr, "\n"); } while (0) |
| #else |
| # define debug(fmt...) do { } while (0) |
| #endif |
| |
| #define NUM_ARRAY_ELEMENTS(a) sizeof(a) / sizeof(a[0]) |
| |
| #if __BYTE_ORDER == __LITTLE_ENDIAN |
| struct domain_hdr { |
| uint16_t id; |
| uint8_t rd:1; |
| uint8_t tc:1; |
| uint8_t aa:1; |
| uint8_t opcode:4; |
| uint8_t qr:1; |
| uint8_t rcode:4; |
| uint8_t z:3; |
| uint8_t ra:1; |
| uint16_t qdcount; |
| uint16_t ancount; |
| uint16_t nscount; |
| uint16_t arcount; |
| } __attribute__ ((packed)); |
| #elif __BYTE_ORDER == __BIG_ENDIAN |
| struct domain_hdr { |
| uint16_t id; |
| uint8_t qr:1; |
| uint8_t opcode:4; |
| uint8_t aa:1; |
| uint8_t tc:1; |
| uint8_t rd:1; |
| uint8_t ra:1; |
| uint8_t z:3; |
| uint8_t rcode:4; |
| uint16_t qdcount; |
| uint16_t ancount; |
| uint16_t nscount; |
| uint16_t arcount; |
| } __attribute__ ((packed)); |
| #else |
| #error "Unknown byte order" |
| #endif |
| |
| struct qtype_qclass { |
| uint16_t qtype; |
| uint16_t qclass; |
| } __attribute__ ((packed)); |
| |
| struct partial_reply { |
| uint16_t len; |
| uint16_t received; |
| unsigned char buf[]; |
| }; |
| |
| struct server_data { |
| int index; |
| GList *domains; |
| char *server; |
| struct sockaddr *server_addr; |
| socklen_t server_addr_len; |
| int protocol; |
| GIOChannel *channel; |
| guint watch; |
| guint timeout; |
| bool enabled; |
| bool connected; |
| struct partial_reply *incoming_reply; |
| }; |
| |
| struct request_data { |
| union { |
| struct sockaddr_in6 __sin6; /* Only for the length */ |
| struct sockaddr sa; |
| }; |
| socklen_t sa_len; |
| int client_sk; |
| int protocol; |
| int family; |
| guint16 srcid; |
| guint16 dstid; |
| guint16 altid; |
| guint timeout; |
| guint watch; |
| guint numserv; |
| guint numresp; |
| gpointer request; |
| gsize request_len; |
| gpointer name; |
| gpointer resp; |
| gsize resplen; |
| struct listener_data *ifdata; |
| bool append_domain; |
| }; |
| |
| struct listener_data { |
| int index; |
| |
| GIOChannel *udp4_listener_channel; |
| GIOChannel *tcp4_listener_channel; |
| guint udp4_listener_watch; |
| guint tcp4_listener_watch; |
| |
| GIOChannel *udp6_listener_channel; |
| GIOChannel *tcp6_listener_channel; |
| guint udp6_listener_watch; |
| guint tcp6_listener_watch; |
| }; |
| |
| /* |
| * The TCP client requires some extra handling as we need to |
| * be prepared to receive also partial DNS requests. |
| */ |
| struct tcp_partial_client_data { |
| int family; |
| struct listener_data *ifdata; |
| GIOChannel *channel; |
| guint watch; |
| unsigned char *buf; |
| unsigned int buf_end; |
| guint timeout; |
| }; |
| |
| struct cache_data { |
| time_t inserted; |
| time_t valid_until; |
| time_t cache_until; |
| int timeout; |
| uint16_t type; |
| uint16_t answers; |
| unsigned int data_len; |
| unsigned char *data; /* contains DNS header + body */ |
| }; |
| |
| struct cache_entry { |
| char *key; |
| bool want_refresh; |
| size_t hits; |
| struct cache_data *ipv4; |
| struct cache_data *ipv6; |
| }; |
| |
| struct cache_timeout { |
| time_t current_time; |
| time_t max_timeout; |
| bool try_harder; |
| }; |
| |
| struct domain_question { |
| uint16_t type; |
| uint16_t class; |
| } __attribute__ ((packed)); |
| |
| struct domain_rr { |
| uint16_t type; |
| uint16_t class; |
| uint32_t ttl; |
| uint16_t rdlen; |
| } __attribute__ ((packed)); |
| |
| /* |
| * Max length of the DNS TCP packet. |
| */ |
| #define TCP_MAX_BUF_LEN 4096 |
| |
| /* |
| * We limit how long the cached DNS entry stays in the cache. |
| * By default the TTL (time-to-live) of the DNS response is used |
| * when setting the cache entry life time. The value is in seconds. |
| */ |
| #define MAX_CACHE_TTL (60 * 30) |
| /* |
| * Also limit the other end, cache at least for 30 seconds. |
| */ |
| #define MIN_CACHE_TTL (30) |
| |
| /* |
| * We limit the cache size to some sane value so that cached data does |
| * not occupy too much memory. Each cached entry occupies on average |
| * about 100 bytes memory (depending on DNS name length). |
| * Example: caching www.connman.net uses 97 bytes memory. |
| * The value is the max amount of cached DNS responses (count). |
| */ |
| #define MAX_CACHE_SIZE 256 |
| |
| #define DNS_HEADER_SIZE sizeof(struct domain_hdr) |
| #define DNS_HEADER_TCP_EXTRA_BYTES 2 |
| #define DNS_TCP_HEADER_SIZE DNS_HEADER_SIZE + DNS_HEADER_TCP_EXTRA_BYTES |
| #define DNS_QUESTION_SIZE sizeof(struct domain_question) |
| #define DNS_RR_SIZE sizeof(struct domain_rr) |
| #define DNS_QTYPE_QCLASS_SIZE sizeof(struct qtype_qclass) |
| |
| enum dns_type { |
| /* IPv4 address 32-bit */ |
| DNS_TYPE_A = ns_t_a, |
| /* IPv6 address 128-bit */ |
| DNS_TYPE_AAAA = ns_t_aaaa, |
| /* alias to another name */ |
| DNS_TYPE_CNAME = ns_t_cname, |
| /* start of a zone of authority */ |
| DNS_TYPE_SOA = ns_t_soa |
| }; |
| |
| enum dns_class { |
| DNS_CLASS_IN = ns_c_in, |
| DNS_CLASS_ANY = ns_c_any /* only valid for QCLASS fields */ |
| }; |
| |
| static int cache_size; |
| static GHashTable *cache; |
| static int cache_refcount; |
| static GSList *server_list; |
| static GSList *request_list; |
| static GHashTable *listener_table; |
| static time_t next_refresh; |
| static GHashTable *partial_tcp_req_table; |
| static guint cache_timer; |
| static in_port_t dns_listen_port = 53; |
| /* we can keep using the same resolve's */ |
| static GResolv *ipv4_resolve; |
| static GResolv *ipv6_resolve; |
| |
| static guint16 get_id(void) |
| { |
| uint64_t rand; |
| |
| /* TODO: return code is ignored, should we rather abort() on error? */ |
| __connman_util_get_random(&rand); |
| |
| return rand; |
| } |
| |
| static size_t protocol_offset(int protocol) |
| { |
| switch (protocol) { |
| case IPPROTO_UDP: |
| return 0; |
| |
| case IPPROTO_TCP: |
| return DNS_HEADER_TCP_EXTRA_BYTES; |
| |
| default: |
| /* this should never happen */ |
| abort(); |
| } |
| } |
| |
| static const char* protocol_label(int protocol) |
| { |
| switch(protocol) { |
| case IPPROTO_UDP: |
| return "UDP"; |
| case IPPROTO_TCP: |
| return "TCP"; |
| default: |
| return "BAD_PROTOCOL"; |
| } |
| } |
| |
| static int socket_type(int protocol, int extra_flags) |
| { |
| switch (protocol) { |
| case IPPROTO_UDP: |
| return SOCK_DGRAM | extra_flags; |
| case IPPROTO_TCP: |
| return SOCK_STREAM | extra_flags; |
| default: |
| /* this should never happen */ |
| abort(); |
| } |
| } |
| |
| /* |
| * There is a power and efficiency benefit to have entries |
| * in our cache expire at the same time. To this extend, |
| * we round down the cache valid time to common boundaries. |
| */ |
| static time_t round_down_ttl(time_t end_time, int ttl) |
| { |
| if (ttl < 15) |
| return end_time; |
| |
| /* Less than 5 minutes, round to 10 second boundary */ |
| if (ttl < 300) { |
| end_time = end_time / 10; |
| end_time = end_time * 10; |
| } else { /* 5 or more minutes, round to 30 seconds */ |
| end_time = end_time / 30; |
| end_time = end_time * 30; |
| } |
| return end_time; |
| } |
| |
| static struct request_data *find_request(guint16 id) |
| { |
| for (GSList *list = request_list; list; list = list->next) { |
| struct request_data *req = list->data; |
| |
| if (req->dstid == id || req->altid == id) |
| return req; |
| } |
| |
| return NULL; |
| } |
| |
| static struct server_data *find_server(int index, |
| const char *server, |
| int protocol) |
| { |
| debug("index %d server %s proto %d", index, server, protocol); |
| |
| for (GSList *list = server_list; list; list = list->next) { |
| struct server_data *data = list->data; |
| |
| if (index < 0 && data->index < 0 && |
| g_str_equal(data->server, server) && |
| data->protocol == protocol) |
| return data; |
| |
| if (index < 0 || |
| data->index < 0 || !data->server) |
| continue; |
| |
| if (data->index == index && |
| g_str_equal(data->server, server) && |
| data->protocol == protocol) |
| return data; |
| } |
| |
| return NULL; |
| } |
| |
| static void dummy_resolve_func(GResolvResultStatus status, |
| char **results, gpointer user_data) |
| { |
| } |
| |
| /* |
| * Refresh a DNS entry, but also age the hit count a bit */ |
| static void refresh_dns_entry(struct cache_entry *entry, char *name) |
| { |
| unsigned int age = 1; |
| |
| if (!ipv4_resolve) { |
| ipv4_resolve = g_resolv_new(0); |
| g_resolv_set_address_family(ipv4_resolve, AF_INET); |
| g_resolv_add_nameserver(ipv4_resolve, "127.0.0.1", 53, 0); |
| } |
| |
| if (!ipv6_resolve) { |
| ipv6_resolve = g_resolv_new(0); |
| g_resolv_set_address_family(ipv6_resolve, AF_INET6); |
| g_resolv_add_nameserver(ipv6_resolve, "::1", 53, 0); |
| } |
| |
| if (!entry->ipv4) { |
| debug("Refreshing A record for %s", name); |
| g_resolv_lookup_hostname(ipv4_resolve, name, |
| dummy_resolve_func, NULL); |
| age = 4; |
| } |
| |
| if (!entry->ipv6) { |
| debug("Refreshing AAAA record for %s", name); |
| g_resolv_lookup_hostname(ipv6_resolve, name, |
| dummy_resolve_func, NULL); |
| age = 4; |
| } |
| |
| if (entry->hits > age) |
| entry->hits -= age; |
| else |
| entry->hits = 0; |
| } |
| |
| static size_t dns_name_length(const unsigned char *buf) |
| { |
| if ((buf[0] & NS_CMPRSFLGS) == NS_CMPRSFLGS) /* compressed name */ |
| return 2; |
| return strlen((const char *)buf) + 1; |
| } |
| |
| static void update_cached_ttl(unsigned char *ptr, size_t len, int new_ttl) |
| { |
| size_t name_len; |
| const uint32_t raw_ttl = ntohl((uint32_t)new_ttl); |
| |
| if (new_ttl < 0 || len < DNS_HEADER_SIZE + DNS_QUESTION_SIZE + 1) |
| return; |
| |
| /* skip the header */ |
| ptr += DNS_HEADER_SIZE; |
| len -= DNS_HEADER_SIZE; |
| |
| /* skip the query, which is a name and a struct domain_question */ |
| name_len = dns_name_length(ptr); |
| |
| if (len < name_len + DNS_QUESTION_SIZE) |
| return; |
| |
| ptr += name_len + DNS_QUESTION_SIZE; |
| len -= name_len + DNS_QUESTION_SIZE; |
| |
| /* now we get the answer records */ |
| |
| while (len > 0) { |
| struct domain_rr *rr = NULL; |
| size_t rr_len; |
| |
| /* first a name */ |
| name_len = dns_name_length(ptr); |
| if (len < name_len) |
| break; |
| |
| ptr += name_len; |
| len -= name_len; |
| |
| rr = (void*)ptr; |
| if (len < sizeof(*rr)) |
| /* incomplete record */ |
| break; |
| |
| /* update the TTL field */ |
| memcpy(&rr->ttl, &raw_ttl, sizeof(raw_ttl)); |
| |
| /* skip to the next record */ |
| rr_len = sizeof(*rr) + ntohs(rr->rdlen); |
| if (len < rr_len) |
| break; |
| |
| ptr += rr_len; |
| len -= rr_len; |
| } |
| } |
| |
| static void send_cached_response(int sk, const unsigned char *ptr, size_t len, |
| const struct sockaddr *to, socklen_t tolen, |
| int protocol, int id, uint16_t answers, int ttl) |
| { |
| struct domain_hdr *hdr = NULL; |
| int err; |
| size_t bytes_sent; |
| const size_t offset = protocol_offset(protocol); |
| /* |
| * The cached packet contains always the TCP offset (two bytes) |
| * so skip them for UDP. |
| */ |
| const size_t skip_bytes = offset ? 0 : DNS_HEADER_TCP_EXTRA_BYTES; |
| size_t dns_len; |
| |
| ptr += skip_bytes; |
| len -= skip_bytes; |
| dns_len = protocol == IPPROTO_UDP ? len : ntohs(*((uint16_t*)ptr)); |
| |
| |
| if (len < DNS_HEADER_SIZE) |
| return; |
| |
| hdr = (void *) (ptr + offset); |
| |
| hdr->id = id; |
| hdr->qr = 1; |
| hdr->rcode = ns_r_noerror; |
| hdr->ancount = htons(answers); |
| hdr->nscount = 0; |
| hdr->arcount = 0; |
| |
| /* if this is a negative reply, we are authoritative */ |
| if (answers == 0) |
| hdr->aa = 1; |
| else |
| update_cached_ttl((unsigned char *)hdr, dns_len, ttl); |
| |
| debug("sk %d id 0x%04x answers %d ptr %p length %zd dns %zd", |
| sk, hdr->id, answers, ptr, len, dns_len); |
| |
| err = sendto(sk, ptr, len, MSG_NOSIGNAL, to, tolen); |
| if (err < 0) { |
| connman_error("Cannot send cached DNS response: %s", |
| strerror(errno)); |
| } |
| |
| bytes_sent = err; |
| if (bytes_sent != len || dns_len != (len - offset)) |
| debug("Packet length mismatch, sent %d wanted %zd dns %zd", |
| err, len, dns_len); |
| } |
| |
| static void send_response(int sk, unsigned char *buf, size_t len, |
| const struct sockaddr *to, socklen_t tolen, |
| int protocol) |
| { |
| struct domain_hdr *hdr; |
| int err; |
| const size_t offset = protocol_offset(protocol); |
| const size_t send_size = DNS_HEADER_SIZE + offset; |
| |
| debug("sk %d", sk); |
| |
| if (len < send_size) |
| return; |
| |
| hdr = (void *) (buf + offset); |
| if (offset) { |
| buf[0] = 0; |
| buf[1] = DNS_HEADER_SIZE; |
| } |
| |
| debug("id 0x%04x qr %d opcode %d", hdr->id, hdr->qr, hdr->opcode); |
| |
| hdr->qr = 1; |
| hdr->rcode = ns_r_servfail; |
| |
| hdr->qdcount = 0; |
| hdr->ancount = 0; |
| hdr->nscount = 0; |
| hdr->arcount = 0; |
| |
| err = sendto(sk, buf, send_size, MSG_NOSIGNAL, to, tolen); |
| if (err < 0) { |
| connman_error("Failed to send DNS response to %d: %s", |
| sk, strerror(errno)); |
| } |
| } |
| |
| static int get_req_udp_socket(struct request_data *req) |
| { |
| GIOChannel *channel; |
| |
| if (req->family == AF_INET) |
| channel = req->ifdata->udp4_listener_channel; |
| else |
| channel = req->ifdata->udp6_listener_channel; |
| |
| if (!channel) |
| return -1; |
| |
| return g_io_channel_unix_get_fd(channel); |
| } |
| |
| static void destroy_request_data(struct request_data *req) |
| { |
| if (req->timeout > 0) |
| g_source_remove(req->timeout); |
| |
| g_free(req->resp); |
| g_free(req->request); |
| g_free(req->name); |
| g_free(req); |
| } |
| |
| static gboolean request_timeout(gpointer user_data) |
| { |
| struct request_data *req = user_data; |
| struct sockaddr *sa; |
| int sk = -1; |
| |
| if (!req) |
| return FALSE; |
| |
| debug("id 0x%04x", req->srcid); |
| |
| request_list = g_slist_remove(request_list, req); |
| |
| if (req->protocol == IPPROTO_UDP) { |
| sk = get_req_udp_socket(req); |
| sa = &req->sa; |
| } else if (req->protocol == IPPROTO_TCP) { |
| sk = req->client_sk; |
| sa = NULL; |
| } |
| |
| if (sk < 0) |
| goto out; |
| |
| if (req->resplen > 0 && req->resp) { |
| /* |
| * Here we have received at least one reply (probably telling |
| * "not found" result), so send that back to client instead |
| * of more fatal server failed error. |
| */ |
| sendto(sk, req->resp, req->resplen, MSG_NOSIGNAL, |
| sa, req->sa_len); |
| |
| } else if (req->request) { |
| /* |
| * There was not reply from server at all. |
| */ |
| struct domain_hdr *hdr = (void *)(req->request + protocol_offset(req->protocol)); |
| hdr->id = req->srcid; |
| |
| send_response(sk, req->request, req->request_len, |
| sa, req->sa_len, req->protocol); |
| } |
| |
| /* |
| * We cannot leave TCP client hanging so just kick it out |
| * if we get a request timeout from server. |
| */ |
| if (req->protocol == IPPROTO_TCP) { |
| debug("client %d removed", req->client_sk); |
| g_hash_table_remove(partial_tcp_req_table, |
| GINT_TO_POINTER(req->client_sk)); |
| } |
| |
| out: |
| req->timeout = 0; |
| destroy_request_data(req); |
| |
| return FALSE; |
| } |
| |
| static int append_data(unsigned char *buf, size_t size, const char *data) |
| { |
| unsigned char *ptr = buf; |
| size_t len; |
| |
| while (true) { |
| const char *dot = strchrnul(data, '.'); |
| len = dot - data; |
| |
| if (len == 0) |
| break; |
| else if (size < len + 1) |
| return -1; |
| |
| *ptr = len; |
| memcpy(ptr + 1, data, len); |
| ptr += len + 1; |
| size -= len + 1; |
| |
| if (!dot) |
| break; |
| |
| data = dot + 1; |
| } |
| |
| return ptr - buf; |
| } |
| |
| static int append_query(unsigned char *buf, size_t size, |
| const char *query, const char *domain) |
| { |
| size_t added; |
| size_t left_size = size; |
| int res; |
| |
| debug("query %s domain %s", query, domain); |
| |
| res = append_data(buf, left_size, query); |
| if (res < 0) |
| return -1; |
| left_size -= res; |
| |
| res = append_data(buf + res, left_size, domain); |
| if (res < 0) |
| return -1; |
| left_size -= res; |
| |
| if (left_size == 0) |
| return -1; |
| |
| added = size - left_size; |
| *(buf + added) = 0x00; |
| |
| return added; |
| } |
| |
| static bool cache_check_is_valid(struct cache_data *data, time_t current_time) |
| { |
| if (!data) |
| return false; |
| else if (data->cache_until < current_time) |
| return false; |
| |
| return true; |
| } |
| |
| static void cache_free_ipv4(struct cache_entry *entry) |
| { |
| if (!entry->ipv4) |
| return; |
| |
| g_free(entry->ipv4->data); |
| g_free(entry->ipv4); |
| entry->ipv4 = NULL; |
| } |
| |
| static void cache_free_ipv6(struct cache_entry *entry) |
| { |
| if (!entry->ipv6) |
| return; |
| |
| g_free(entry->ipv6->data); |
| g_free(entry->ipv6); |
| entry->ipv6 = NULL; |
| } |
| |
| /* |
| * remove stale cached entries so that they can be refreshed |
| */ |
| static void cache_enforce_validity(struct cache_entry *entry) |
| { |
| time_t current_time = time(NULL); |
| |
| if (entry->ipv4 && !cache_check_is_valid(entry->ipv4, current_time)) { |
| debug("cache timeout \"%s\" type A", entry->key); |
| cache_free_ipv4(entry); |
| } |
| |
| if (entry->ipv6 && !cache_check_is_valid(entry->ipv6, current_time)) { |
| debug("cache timeout \"%s\" type AAAA", entry->key); |
| cache_free_ipv6(entry); |
| } |
| } |
| |
| static bool cache_check_validity(const char *question, uint16_t type, |
| struct cache_entry *entry) |
| { |
| struct cache_data *cached_ip = NULL, *other_ip = NULL; |
| const time_t current_time = time(NULL); |
| bool want_refresh; |
| |
| cache_enforce_validity(entry); |
| |
| switch (type) { |
| case DNS_TYPE_A: /* IPv4 */ |
| cached_ip = entry->ipv4; |
| other_ip = entry->ipv6; |
| break; |
| |
| case DNS_TYPE_AAAA: /* IPv6 */ |
| cached_ip = entry->ipv6; |
| other_ip = entry->ipv4; |
| break; |
| default: |
| return false; |
| } |
| |
| /* |
| * if we have a popular entry, we want a refresh instead of |
| * total destruction of the entry. |
| */ |
| want_refresh = entry->hits > 2 ? true : false; |
| |
| if (!cache_check_is_valid(cached_ip, current_time)) { |
| debug("cache %s \"%s\" type %s", |
| cached_ip ? "timeout" : "entry missing", |
| question, |
| cached_ip == entry->ipv4 ? "A" : "AAAA"); |
| |
| if (want_refresh) |
| entry->want_refresh = true; |
| /* |
| * We do not remove cache entry if there is still a |
| * valid entry for another IP version found in the cache. |
| */ |
| else if (!cache_check_is_valid(other_ip, current_time)) { |
| g_hash_table_remove(cache, question); |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| static void cache_element_destroy(gpointer value) |
| { |
| struct cache_entry *entry = value; |
| |
| if (!entry) |
| return; |
| |
| cache_free_ipv4(entry); |
| cache_free_ipv6(entry); |
| |
| g_free(entry->key); |
| g_free(entry); |
| |
| /* TODO: this would be a worrying condition. Does this ever happen? */ |
| if (--cache_size < 0) |
| cache_size = 0; |
| } |
| |
| static gboolean try_remove_cache(gpointer user_data) |
| { |
| cache_timer = 0; |
| |
| if (__sync_fetch_and_sub(&cache_refcount, 1) == 1) { |
| debug("No cache users, removing it."); |
| |
| g_hash_table_destroy(cache); |
| cache = NULL; |
| cache_size = 0; |
| } |
| |
| return FALSE; |
| } |
| |
| static void create_cache(void) |
| { |
| if (__sync_fetch_and_add(&cache_refcount, 1) == 0) { |
| cache = g_hash_table_new_full(g_str_hash, |
| g_str_equal, |
| NULL, |
| cache_element_destroy); |
| cache_size = 0; |
| } |
| } |
| |
| static struct cache_entry *cache_check(gpointer request, uint16_t *qtype, int proto) |
| { |
| const char *question; |
| size_t offset; |
| const struct domain_question *q; |
| uint16_t type; |
| struct cache_entry *entry; |
| |
| if (!request) |
| return NULL; |
| |
| question = request + protocol_offset(proto) + DNS_HEADER_SIZE; |
| offset = strlen(question) + 1; |
| q = (void *) (question + offset); |
| type = ntohs(q->type); |
| |
| /* We only cache either A (1) or AAAA (28) requests */ |
| if (type != DNS_TYPE_A && type != DNS_TYPE_AAAA) |
| return NULL; |
| |
| if (!cache) { |
| create_cache(); |
| return NULL; |
| } |
| |
| entry = g_hash_table_lookup(cache, question); |
| if (!entry) |
| return NULL; |
| |
| if (!cache_check_validity(question, type, entry)) |
| return NULL; |
| |
| *qtype = type; |
| return entry; |
| } |
| |
| /* |
| * Get a label/name from DNS resource record. The function decompresses the |
| * label if necessary. The function does not convert the name to presentation |
| * form. This means that the result string will contain label lengths instead |
| * of dots between labels. We intentionally do not want to convert to dotted |
| * format so that we can cache the wire format string directly. |
| */ |
| static int get_name(int counter, |
| const unsigned char *pkt, const unsigned char *start, const unsigned char *max, |
| unsigned char *output, int output_max, int *output_len, |
| const unsigned char **end, char *name, size_t max_name, int *name_len) |
| { |
| const unsigned char *p = start; |
| |
| /* Limit recursion to 10 (this means up to 10 labels in domain name) */ |
| if (counter > 10) |
| return -EINVAL; |
| |
| while (*p) { |
| if ((*p & NS_CMPRSFLGS) == NS_CMPRSFLGS) { |
| const uint16_t offset = (*p & 0x3F) * 256 + *(p + 1); |
| |
| if (offset >= max - pkt) |
| return -ENOBUFS; |
| |
| if (!*end) |
| *end = p + 2; |
| |
| return get_name(counter + 1, pkt, pkt + offset, max, |
| output, output_max, output_len, end, |
| name, max_name, name_len); |
| } else { |
| unsigned label_len = *p; |
| |
| if (pkt + label_len > max) |
| return -ENOBUFS; |
| else if (*output_len > output_max) |
| return -ENOBUFS; |
| else if ((*name_len + 1 + label_len + 1) > max_name) |
| return -ENOBUFS; |
| |
| /* |
| * We need the original name in order to check |
| * if this answer is the correct one. |
| */ |
| name[(*name_len)++] = label_len; |
| memcpy(name + *name_len, p + 1, label_len + 1); |
| *name_len += label_len; |
| |
| /* We compress the result */ |
| output[0] = NS_CMPRSFLGS; |
| output[1] = 0x0C; |
| *output_len = 2; |
| |
| p += label_len + 1; |
| |
| if (!*end) |
| *end = p; |
| |
| if (p >= max) |
| return -ENOBUFS; |
| } |
| } |
| |
| return 0; |
| } |
| |
| static int parse_rr(const unsigned char *buf, const unsigned char *start, |
| const unsigned char *max, |
| unsigned char *response, size_t *response_size, |
| uint16_t *type, uint16_t *class, int *ttl, uint16_t *rdlen, |
| const unsigned char **end, |
| char *name, size_t max_name) |
| { |
| struct domain_rr *rr; |
| size_t offset; |
| int name_len = 0, output_len = 0, max_rsp = *response_size; |
| int err = get_name(0, buf, start, max, response, max_rsp, |
| &output_len, end, name, max_name, &name_len); |
| |
| if (err < 0) |
| return err; |
| |
| offset = output_len; |
| |
| if (offset > *response_size) |
| return -ENOBUFS; |
| |
| rr = (void *) (*end); |
| |
| if (!rr) |
| return -EINVAL; |
| |
| *type = ntohs(rr->type); |
| *class = ntohs(rr->class); |
| *ttl = ntohl(rr->ttl); |
| *rdlen = ntohs(rr->rdlen); |
| |
| if (*ttl < 0) |
| return -EINVAL; |
| |
| memcpy(response + offset, *end, DNS_RR_SIZE); |
| |
| offset += DNS_RR_SIZE; |
| *end += DNS_RR_SIZE; |
| |
| if ((offset + *rdlen) > *response_size) |
| return -ENOBUFS; |
| |
| memcpy(response + offset, *end, *rdlen); |
| |
| *end += *rdlen; |
| *response_size = offset + *rdlen; |
| |
| return 0; |
| } |
| |
| static bool check_alias(GSList *aliases, const char *name) |
| { |
| if (aliases) { |
| for (GSList *list = aliases; list; list = list->next) { |
| const char *cmpname = (const char*)list->data; |
| if (strncmp(cmpname, name, NS_MAXDNAME) == 0) |
| return true; |
| } |
| } |
| |
| return false; |
| } |
| |
| /* |
| * Parses the DNS response packet found in 'buf' consisting of 'buflen' bytes. |
| * |
| * The parsed question label, response type and class, ttl and number of |
| * answer sections are output parameters. The response output buffer will |
| * receive all matching resource records to be cached. |
| * |
| * Return value is < 0 on error (negative errno) or zero on success. |
| */ |
| static int parse_response(const unsigned char *buf, size_t buflen, |
| char *question, size_t qlen, |
| uint16_t *type, uint16_t *class, int *ttl, |
| unsigned char *response, size_t *response_len, |
| uint16_t *answers) |
| { |
| struct domain_hdr *hdr = (void *) buf; |
| struct domain_question *q; |
| uint16_t qtype; |
| int err = -ENOMSG; |
| uint16_t ancount, qclass; |
| GSList *aliases = NULL; |
| const size_t maxlen = *response_len; |
| uint16_t qdcount; |
| const unsigned char *ptr; |
| const unsigned char *eptr; |
| |
| *response_len = 0; |
| *answers = 0; |
| |
| if (buflen < DNS_HEADER_SIZE) |
| return -EINVAL; |
| |
| qdcount = ntohs(hdr->qdcount); |
| ptr = buf + DNS_HEADER_SIZE; |
| eptr = buf + buflen; |
| |
| debug("qr %d qdcount %d", hdr->qr, qdcount); |
| |
| /* We currently only cache responses where question count is 1 */ |
| if (hdr->qr != 1 || qdcount != 1) |
| return -EINVAL; |
| |
| /* |
| * NOTE: currently the *caller* ensures that the `question' buffer is |
| * always zero terminated. |
| */ |
| strncpy(question, (const char *) ptr, MIN(qlen, buflen - DNS_HEADER_SIZE)); |
| qlen = strlen(question); |
| ptr += qlen + 1; /* skip \0 */ |
| |
| if (ptr + DNS_QUESTION_SIZE >= eptr) |
| return -EINVAL; |
| |
| q = (void *) ptr; |
| qtype = ntohs(q->type); |
| |
| /* We cache only A and AAAA records */ |
| if (qtype != DNS_TYPE_A && qtype != DNS_TYPE_AAAA) |
| return -ENOMSG; |
| |
| ptr += DNS_QUESTION_SIZE; /* advance to answers section */ |
| |
| ancount = ntohs(hdr->ancount); |
| qclass = ntohs(q->class); |
| |
| /* |
| * We have a bunch of answers (like A, AAAA, CNAME etc) to |
| * A or AAAA question. We traverse the answers and parse the |
| * resource records. Only A and AAAA records are cached, all |
| * the other records in answers are skipped. |
| */ |
| for (uint16_t i = 0; i < ancount; i++) { |
| char name[NS_MAXDNAME + 1] = {0}; |
| /* |
| * Get one address at a time to this buffer. |
| * The max size of the answer is |
| * 2 (pointer) + 2 (type) + 2 (class) + |
| * 4 (ttl) + 2 (rdlen) + addr (16 or 4) = 28 |
| * for A or AAAA record. |
| * For CNAME the size can be bigger. |
| * TODO: why are we using the MAXCDNAME constant as buffer |
| * size then? |
| */ |
| unsigned char rsp[NS_MAXCDNAME] = {0}; |
| size_t rsp_len = sizeof(rsp) - 1; |
| const unsigned char *next = NULL; |
| uint16_t rdlen; |
| |
| int ret = parse_rr(buf, ptr, buf + buflen, rsp, &rsp_len, |
| type, class, ttl, &rdlen, &next, name, |
| sizeof(name) - 1); |
| if (ret != 0) { |
| err = ret; |
| break; |
| } |
| |
| /* set pointer to the next RR for the next iteration */ |
| ptr = next; |
| |
| /* |
| * Now rsp contains a compressed or an uncompressed resource |
| * record. Next we check if this record answers the question. |
| * The name var contains the uncompressed label. |
| * One tricky bit is the CNAME records as they alias |
| * the name we might be interested in. |
| */ |
| |
| /* |
| * Go to next answer if the class is not the one we are |
| * looking for. |
| */ |
| if (*class != qclass) { |
| continue; |
| } |
| |
| /* |
| * Try to resolve aliases also, type is CNAME(5). |
| * This is important as otherwise the aliased names would not |
| * be cached at all as the cache would not contain the aliased |
| * question. |
| * |
| * If any CNAME is found in DNS packet, then we cache the alias |
| * IP address instead of the question (as the server |
| * said that question has only an alias). |
| * This means in practice that if e.g., ipv6.google.com is |
| * queried, DNS server returns CNAME of that name which is |
| * ipv6.l.google.com. We then cache the address of the CNAME |
| * but return the question name to client. So the alias |
| * status of the name is not saved in cache and thus not |
| * returned to the client. We do not return DNS packets from |
| * cache to client saying that ipv6.google.com is an alias to |
| * ipv6.l.google.com but we return instead a DNS packet that |
| * says ipv6.google.com has address xxx which is in fact the |
| * address of ipv6.l.google.com. For caching purposes this |
| * should not cause any issues. |
| */ |
| if (*type == DNS_TYPE_CNAME && strncmp(question, name, qlen) == 0) { |
| /* |
| * So now the alias answered the question. This is |
| * not very useful from caching point of view as |
| * the following A or AAAA records will not match the |
| * question. We need to find the real A/AAAA record |
| * of the alias and cache that. |
| */ |
| const unsigned char *end = NULL; |
| int name_len = 0, output_len = 0; |
| |
| memset(rsp, 0, sizeof(rsp)); |
| rsp_len = sizeof(rsp) - 1; |
| |
| /* |
| * Alias is in rdata part of the message, |
| * and next-rdlen points to it. So we need to get |
| * the real name of the alias. |
| */ |
| ret = get_name(0, buf, next - rdlen, buf + buflen, |
| rsp, rsp_len, &output_len, &end, |
| name, sizeof(name) - 1, &name_len); |
| if (ret != 0) { |
| /* just ignore the error at this point */ |
| continue; |
| } |
| |
| /* |
| * We should now have the alias of the entry we might |
| * want to cache. Just remember it for a while. |
| * We check the alias list when we have parsed the |
| * A or AAAA record. |
| */ |
| aliases = g_slist_prepend(aliases, g_strdup(name)); |
| |
| continue; |
| } else if (*type == qtype) { |
| /* |
| * We found correct type (A or AAAA) |
| */ |
| if (check_alias(aliases, name) || |
| (!aliases && strncmp(question, name, |
| qlen) == 0)) { |
| /* |
| * We found an alias or the name of the rr |
| * matches the question. If so, we append |
| * the compressed label to the cache. |
| * The end result is a response buffer that |
| * will contain one or more cached and |
| * compressed resource records. |
| */ |
| if (*response_len + rsp_len > maxlen) { |
| err = -ENOBUFS; |
| break; |
| } |
| memcpy(response + *response_len, rsp, rsp_len); |
| *response_len += rsp_len; |
| (*answers)++; |
| err = 0; |
| } |
| } |
| } |
| |
| for (GSList *list = aliases; list; list = list->next) |
| g_free(list->data); |
| g_slist_free(aliases); |
| |
| return err; |
| } |
| |
| static gboolean cache_check_entry(gpointer key, gpointer value, |
| gpointer user_data) |
| { |
| struct cache_timeout *data = user_data; |
| struct cache_entry *entry = value; |
| time_t max_timeout; |
| |
| /* Scale the number of hits by half as part of cache aging */ |
| |
| entry->hits /= 2; |
| |
| /* |
| * If either IPv4 or IPv6 cached entry has expired, we |
| * remove both from the cache. |
| */ |
| |
| if (entry->ipv4 && entry->ipv4->timeout > 0) { |
| max_timeout = entry->ipv4->cache_until; |
| if (max_timeout > data->max_timeout) |
| data->max_timeout = max_timeout; |
| |
| if (entry->ipv4->cache_until < data->current_time) |
| return TRUE; |
| } |
| |
| if (entry->ipv6 && entry->ipv6->timeout > 0) { |
| max_timeout = entry->ipv6->cache_until; |
| if (max_timeout > data->max_timeout) |
| data->max_timeout = max_timeout; |
| |
| if (entry->ipv6->cache_until < data->current_time) |
| return TRUE; |
| } |
| |
| /* |
| * if we're asked to try harder, also remove entries that have |
| * few hits |
| */ |
| if (data->try_harder && entry->hits < 4) |
| return TRUE; |
| |
| return FALSE; |
| } |
| |
| static void cache_cleanup(void) |
| { |
| static time_t max_timeout; |
| struct cache_timeout data = { |
| .current_time = time(NULL), |
| .max_timeout = 0, |
| .try_harder = false |
| }; |
| int count = 0; |
| |
| /* |
| * In the first pass, we only remove entries that have timed out. |
| * We use a cache of the first time to expire to do this only |
| * when it makes sense. |
| */ |
| if (max_timeout <= data.current_time) { |
| count = g_hash_table_foreach_remove(cache, cache_check_entry, |
| &data); |
| } |
| debug("removed %d in the first pass", count); |
| |
| /* |
| * In the second pass, if the first pass turned up blank, |
| * we also expire entries with a low hit count, |
| * while aging the hit count at the same time. |
| */ |
| data.try_harder = true; |
| if (count == 0) |
| count = g_hash_table_foreach_remove(cache, cache_check_entry, |
| &data); |
| |
| if (count == 0) |
| /* |
| * If we could not remove anything, then remember |
| * what is the max timeout and do nothing if we |
| * have not yet reached it. This will prevent |
| * constant traversal of the cache if it is full. |
| */ |
| max_timeout = data.max_timeout; |
| else |
| max_timeout = 0; |
| } |
| |
| static gboolean cache_invalidate_entry(gpointer key, gpointer value, |
| gpointer user_data) |
| { |
| struct cache_entry *entry = value; |
| |
| /* first, delete any expired elements */ |
| cache_enforce_validity(entry); |
| |
| /* if anything is not expired, mark the entry for refresh */ |
| if (entry->hits > 0 && (entry->ipv4 || entry->ipv6)) |
| entry->want_refresh = true; |
| |
| /* delete the cached data */ |
| cache_free_ipv4(entry); |
| cache_free_ipv6(entry); |
| |
| /* keep the entry if we want it refreshed, delete it otherwise */ |
| return entry->want_refresh ? FALSE : TRUE; |
| } |
| |
| /* |
| * cache_invalidate is called from places where the DNS landscape |
| * has changed, say because connections are added or we entered a VPN. |
| * The logic is to wipe all cache data, but mark all non-expired |
| * parts of the cache for refresh rather than deleting the whole cache. |
| */ |
| static void cache_invalidate(void) |
| { |
| debug("Invalidating the DNS cache %p", cache); |
| |
| if (!cache) |
| return; |
| |
| g_hash_table_foreach_remove(cache, cache_invalidate_entry, NULL); |
| } |
| |
| static void cache_refresh_entry(struct cache_entry *entry) |
| { |
| cache_enforce_validity(entry); |
| |
| if (entry->hits > 2 && (!entry->ipv4 || !entry->ipv6)) |
| entry->want_refresh = true; |
| |
| if (entry->want_refresh) { |
| char dns_name[NS_MAXDNAME + 1]; |
| char *c; |
| |
| entry->want_refresh = false; |
| |
| /* turn a DNS name into a hostname with dots */ |
| strncpy(dns_name, entry->key, NS_MAXDNAME); |
| c = dns_name; |
| while (*c) { |
| /* fetch the size of the current component and replace |
| it by a dot */ |
| int jump = *c; |
| *c = '.'; |
| c += jump + 1; |
| } |
| debug("Refreshing %s\n", dns_name); |
| /* then refresh the hostname */ |
| refresh_dns_entry(entry, &dns_name[1]); |
| } |
| } |
| |
| static void cache_refresh_iterator(gpointer key, gpointer value, |
| gpointer user_data) |
| { |
| struct cache_entry *entry = value; |
| |
| cache_refresh_entry(entry); |
| } |
| |
| static void cache_refresh(void) |
| { |
| if (!cache) |
| return; |
| |
| g_hash_table_foreach(cache, cache_refresh_iterator, NULL); |
| } |
| |
| static int reply_query_type(const unsigned char *msg, int len) |
| { |
| /* skip the header */ |
| const unsigned char *c = msg + DNS_HEADER_SIZE; |
| int type; |
| len -= DNS_HEADER_SIZE; |
| |
| if (len < 0) |
| return 0; |
| |
| /* now the query, which is a name and 2 16 bit words for type and class */ |
| c += dns_name_length(c); |
| |
| type = c[0] << 8 | c[1]; |
| |
| return type; |
| } |
| |
| /* |
| * update the cache with the DNS reply found in msg |
| */ |
| static int cache_update(struct server_data *srv, const unsigned char *msg, size_t msg_len) |
| { |
| const size_t offset = protocol_offset(srv->protocol); |
| int err, ttl = 0; |
| uint16_t *lenhdr; |
| size_t qlen; |
| bool is_new_entry = false; |
| uint16_t answers = 0, type = 0, class = 0; |
| struct domain_hdr *hdr = (void *)(msg + offset); |
| struct domain_question *q = NULL; |
| struct cache_entry *entry; |
| struct cache_data *data; |
| char question[NS_MAXDNAME + 1]; |
| unsigned char response[NS_MAXDNAME + 1]; |
| unsigned char *ptr = NULL; |
| size_t rsplen = sizeof(response) - 1; |
| const time_t current_time = time(NULL); |
| |
| if (cache_size >= MAX_CACHE_SIZE) { |
| cache_cleanup(); |
| if (cache_size >= MAX_CACHE_SIZE) |
| return 0; |
| } |
| |
| /* don't do a cache refresh more than twice a minute */ |
| if (next_refresh < current_time) { |
| cache_refresh(); |
| next_refresh = current_time + 30; |
| } |
| |
| debug("offset %zd hdr %p msg %p rcode %d", offset, hdr, msg, hdr->rcode); |
| |
| /* Continue only if response code is 0 (=ok) */ |
| if (hdr->rcode != ns_r_noerror) |
| return 0; |
| |
| if (!cache) |
| create_cache(); |
| |
| question[sizeof(question) - 1] = '\0'; |
| err = parse_response(msg + offset, msg_len - offset, |
| question, sizeof(question) - 1, |
| &type, &class, &ttl, |
| response, &rsplen, &answers); |
| |
| /* |
| * special case: if we do a ipv6 lookup and get no result |
| * for a record that's already in our ipv4 cache.. we want |
| * to cache the negative response. |
| */ |
| if ((err == -ENOMSG || err == -ENOBUFS) && |
| reply_query_type(msg + offset, |
| msg_len - offset) == DNS_TYPE_AAAA) { |
| entry = g_hash_table_lookup(cache, question); |
| if (entry && entry->ipv4 && !entry->ipv6) { |
| struct cache_data *data = g_try_new(struct cache_data, 1); |
| |
| if (!data) |
| return -ENOMEM; |
| data->inserted = entry->ipv4->inserted; |
| data->type = type; |
| data->answers = ntohs(hdr->ancount); |
| data->timeout = entry->ipv4->timeout; |
| data->data_len = msg_len + |
| (offset ? 0 : DNS_HEADER_TCP_EXTRA_BYTES); |
| data->data = g_malloc(data->data_len); |
| ptr = data->data; |
| if (srv->protocol == IPPROTO_UDP) { |
| /* add the two bytes length header also for |
| * UDP responses */ |
| lenhdr = (void*)ptr; |
| *lenhdr = htons(data->data_len - |
| DNS_HEADER_TCP_EXTRA_BYTES); |
| ptr += DNS_HEADER_TCP_EXTRA_BYTES; |
| } |
| data->valid_until = entry->ipv4->valid_until; |
| data->cache_until = entry->ipv4->cache_until; |
| memcpy(ptr, msg, msg_len); |
| entry->ipv6 = data; |
| /* |
| * we will get a "hit" when we serve the response |
| * out of the cache |
| */ |
| entry->hits = entry->hits ? entry->hits - 1 : 0; |
| return 0; |
| } |
| } |
| |
| if (err < 0 || ttl == 0) |
| return 0; |
| |
| /* |
| * If the cache contains already data, check if the |
| * type of the cached data is the same and do not add |
| * to cache if data is already there. |
| * This is needed so that we can cache both A and AAAA |
| * records for the same name. |
| */ |
| |
| entry = g_hash_table_lookup(cache, question); |
| data = NULL; |
| is_new_entry = !entry; |
| |
| if (!entry) { |
| entry = g_try_new(struct cache_entry, 1); |
| if (!entry) |
| return -ENOMEM; |
| |
| data = g_try_new(struct cache_data, 1); |
| if (!data) { |
| g_free(entry); |
| return -ENOMEM; |
| } |
| |
| entry->key = g_strdup(question); |
| entry->ipv4 = entry->ipv6 = NULL; |
| entry->want_refresh = false; |
| entry->hits = 0; |
| |
| } else { |
| if (type == DNS_TYPE_A && entry->ipv4) |
| return 0; |
| else if (type == DNS_TYPE_AAAA && entry->ipv6) |
| return 0; |
| |
| data = g_try_new(struct cache_data, 1); |
| if (!data) |
| return -ENOMEM; |
| |
| /* |
| * compensate for the hit we'll get for serving |
| * the response out of the cache |
| */ |
| entry->hits = entry->hits ? entry->hits - 1 : 0; |
| } |
| |
| if (type == DNS_TYPE_A) |
| entry->ipv4 = data; |
| else |
| entry->ipv6 = data; |
| |
| if (ttl < MIN_CACHE_TTL) |
| ttl = MIN_CACHE_TTL; |
| |
| data->inserted = current_time; |
| data->type = type; |
| data->answers = answers; |
| data->timeout = ttl; |
| data->valid_until = current_time + ttl; |
| |
| qlen = strlen(question); |
| /* |
| * We allocate the extra TCP header bytes here even for UDP packet |
| * because it simplifies the sending of cached packet. |
| */ |
| data->data_len = DNS_TCP_HEADER_SIZE + qlen + 1 + 2 + 2 + rsplen; |
| data->data = g_malloc(data->data_len); |
| if (!data->data) { |
| g_free(entry->key); |
| g_free(data); |
| g_free(entry); |
| return -ENOMEM; |
| } |
| |
| /* |
| * Restrict the cached DNS record TTL to some sane value |
| * in order to prevent data staying in the cache too long. |
| */ |
| if (ttl > MAX_CACHE_TTL) |
| ttl = MAX_CACHE_TTL; |
| |
| data->cache_until = round_down_ttl(current_time + ttl, ttl); |
| |
| ptr = data->data; |
| |
| /* |
| * We cache the two extra bytes at the start of the message |
| * in a TCP packet. When sending UDP packet, we pad the first |
| * two bytes. This way we do not need to know the format |
| * (UDP/TCP) of the cached message. |
| */ |
| lenhdr = (void*)ptr; |
| *lenhdr = htons(data->data_len - DNS_HEADER_TCP_EXTRA_BYTES); |
| ptr += DNS_HEADER_TCP_EXTRA_BYTES; |
| |
| memcpy(ptr, hdr, DNS_HEADER_SIZE); |
| ptr += DNS_HEADER_SIZE; |
| |
| memcpy(ptr, question, qlen + 1); /* copy also the \0 */ |
| ptr += qlen + 1; |
| |
| q = (void *)ptr; |
| q->type = htons(type); |
| q->class = htons(class); |
| ptr += DNS_QUESTION_SIZE; |
| |
| memcpy(ptr, response, rsplen); |
| |
| if (is_new_entry) { |
| g_hash_table_replace(cache, entry->key, entry); |
| cache_size++; |
| } |
| |
| debug("cache %d %squestion \"%s\" type %d ttl %d size %zd packet %u " |
| "dns len %u", |
| cache_size, is_new_entry ? "new " : "old ", |
| question, type, ttl, |
| sizeof(*entry) + sizeof(*data) + data->data_len + qlen, |
| data->data_len, |
| srv->protocol == IPPROTO_TCP ? |
| (unsigned int)(data->data[0] * 256 + data->data[1]) : |
| data->data_len); |
| |
| return 0; |
| } |
| |
| /* |
| * attempts to answer the given request from cached replies. |
| * |
| * returns: |
| * > 0 on cache hit (answer is already sent out to client) |
| * == 0 on cache miss |
| * < 0 on error condition (errno) |
| */ |
| static int ns_try_resolv_from_cache( |
| struct request_data *req, gpointer request, const char *lookup) |
| { |
| uint16_t type = 0; |
| int ttl_left; |
| struct cache_data *data; |
| struct cache_entry *entry = cache_check(request, &type, req->protocol); |
| if (!entry) |
| return 0; |
| |
| debug("cache hit %s type %s", lookup, type == 1 ? "A" : "AAAA"); |
| |
| data = type == DNS_TYPE_A ? entry->ipv4 : entry->ipv6; |
| |
| if (!data) |
| return 0; |
| |
| ttl_left = data->valid_until - time(NULL); |
| entry->hits++; |
| |
| switch(req->protocol) { |
| case IPPROTO_TCP: |
| send_cached_response(req->client_sk, data->data, |
| data->data_len, NULL, 0, IPPROTO_TCP, |
| req->srcid, data->answers, ttl_left); |
| return 1; |
| case IPPROTO_UDP: { |
| int udp_sk = get_req_udp_socket(req); |
| |
| if (udp_sk < 0) |
| return -EIO; |
| |
| send_cached_response(udp_sk, data->data, |
| data->data_len, &req->sa, req->sa_len, |
| IPPROTO_UDP, req->srcid, data->answers, |
| ttl_left); |
| return 1; |
| } |
| } |
| |
| return -EINVAL; |
| } |
| |
| static int ns_resolv(struct server_data *server, struct request_data *req, |
| gpointer request, gpointer name) |
| { |
| int sk = -1; |
| const char *lookup = (const char *)name; |
| int err = ns_try_resolv_from_cache(req, request, lookup); |
| |
| if (err > 0) |
| /* cache hit */ |
| return 1; |
| else if (err != 0) |
| /* error other than cache miss, don't continue */ |
| return err; |
| |
| /* forward request to real DNS server */ |
| sk = g_io_channel_unix_get_fd(server->channel); |
| |
| err = sendto(sk, request, req->request_len, MSG_NOSIGNAL, |
| server->server_addr, server->server_addr_len); |
| if (err < 0) { |
| debug("Cannot send message to server %s sock %d " |
| "protocol %d (%s/%d)", |
| server->server, sk, server->protocol, |
| strerror(errno), errno); |
| return -EIO; |
| } |
| |
| req->numserv++; |
| |
| /* If we have more than one dot, we don't add domains */ |
| { |
| const char *dot = strchr(lookup, '.'); |
| if (dot && dot != lookup + strlen(lookup) - 1) |
| return 0; |
| } |
| |
| if (server->domains && server->domains->data) |
| req->append_domain = true; |
| |
| for (GList *list = server->domains; list; list = list->next) { |
| int domlen, altlen; |
| unsigned char alt[1024]; |
| const char *domain = list->data; |
| const size_t offset = protocol_offset(server->protocol); |
| struct domain_hdr *hdr = (void *) (&alt[0] + offset); |
| |
| if (!domain) |
| continue; |
| |
| domlen = strlen(domain) + 1; |
| |
| if (domlen < 5) |
| return -EINVAL; |
| |
| memcpy(alt + offset, &req->altid, sizeof(req->altid)); |
| |
| memcpy(alt + offset + 2, request + offset + 2, DNS_HEADER_SIZE - 2); |
| hdr->qdcount = htons(1); |
| |
| altlen = append_query(alt + offset + DNS_HEADER_SIZE, sizeof(alt) - DNS_HEADER_SIZE - offset, |
| name, domain); |
| if (altlen < 0) |
| return -EINVAL; |
| |
| altlen += DNS_HEADER_SIZE; |
| altlen += offset; |
| |
| memcpy(alt + altlen, |
| request + altlen - domlen, |
| req->request_len - altlen + domlen); |
| |
| if (server->protocol == IPPROTO_TCP) { |
| uint16_t req_len = req->request_len + domlen - DNS_HEADER_TCP_EXTRA_BYTES; |
| uint16_t *len_hdr = (void*)alt; |
| *len_hdr = htons(req_len); |
| } |
| |
| debug("req %p dstid 0x%04x altid 0x%04x", req, req->dstid, |
| req->altid); |
| |
| err = send(sk, alt, req->request_len + domlen, MSG_NOSIGNAL); |
| if (err < 0) |
| return -EIO; |
| |
| req->numserv++; |
| } |
| |
| return 0; |
| } |
| |
| static bool convert_label(const char *start, const char *end, const char *ptr, char *uptr, |
| int remaining_len, int *used_comp, int *used_uncomp) |
| { |
| int comp_pos; |
| char name[NS_MAXLABEL]; |
| |
| const int pos = dn_expand((const u_char *)start, (const u_char *)end, (const u_char *)ptr, |
| name, NS_MAXLABEL); |
| if (pos < 0) { |
| debug("uncompress error [%d/%s]", errno, strerror(errno)); |
| return false; |
| } |
| |
| /* |
| * We need to compress back the name so that we get back to internal |
| * label presentation. |
| */ |
| comp_pos = dn_comp(name, (u_char *)uptr, remaining_len, NULL, NULL); |
| if (comp_pos < 0) { |
| debug("compress error [%d/%s]", errno, strerror(errno)); |
| return false; |
| } |
| |
| *used_comp = pos; |
| *used_uncomp = comp_pos; |
| |
| return true; |
| } |
| |
| static const char* uncompress(int16_t field_count, const char *start, const char *end, |
| const char *ptr, char *uncompressed, int uncomp_len, |
| char **uncompressed_ptr) |
| { |
| char *uptr = *uncompressed_ptr; /* position in result buffer */ |
| char * const uncomp_end = uncompressed + uncomp_len - 1; |
| |
| debug("count %d ptr %p end %p uptr %p", field_count, ptr, end, uptr); |
| |
| while (field_count-- > 0 && ptr < end) { |
| int dlen; /* data field length */ |
| int ulen; /* uncompress length */ |
| int pos; /* position in compressed string */ |
| char name[NS_MAXLABEL]; /* tmp label */ |
| uint16_t dns_type, dns_class; |
| int comp_pos; |
| |
| if (!convert_label(start, end, ptr, name, NS_MAXLABEL, |
| &pos, &comp_pos)) |
| return NULL; |
| |
| /* |
| * Copy the uncompressed resource record, type, class and \0 to |
| * tmp buffer. |
| */ |
| |
| ulen = strlen(name) + 1; |
| if ((uptr + ulen) > uncomp_end) |
| return NULL; |
| memcpy(uptr, name, ulen); |
| |
| debug("pos %d ulen %d left %d name %s", pos, ulen, |
| (int)(uncomp_end - (uptr + ulen)), uptr); |
| |
| uptr += ulen; |
| |
| ptr += pos; |
| |
| /* |
| * We copy also the fixed portion of the result (type, class, |
| * ttl, address length and the address) |
| */ |
| if ((uptr + NS_RRFIXEDSZ) > uncomp_end) { |
| debug("uncompressed data too large for buffer"); |
| return NULL; |
| } |
| memcpy(uptr, ptr, NS_RRFIXEDSZ); |
| |
| dns_type = uptr[0] << 8 | uptr[1]; |
| dns_class = uptr[2] << 8 | uptr[3]; |
| |
| if (dns_class != DNS_CLASS_IN) |
| return NULL; |
| |
| ptr += NS_RRFIXEDSZ; |
| uptr += NS_RRFIXEDSZ; |
| |
| /* |
| * Then the variable portion of the result (data length). |
| * Typically this portion is also compressed |
| * so we need to uncompress it also when necessary. |
| */ |
| if (dns_type == DNS_TYPE_CNAME) { |
| if (!convert_label(start, end, ptr, uptr, |
| uncomp_len - (uptr - uncompressed), |
| &pos, &comp_pos)) |
| return NULL; |
| |
| uptr[-2] = comp_pos << 8; |
| uptr[-1] = comp_pos & 0xff; |
| |
| uptr += comp_pos; |
| ptr += pos; |
| |
| } else if (dns_type == DNS_TYPE_A || dns_type == DNS_TYPE_AAAA) { |
| dlen = uptr[-2] << 8 | uptr[-1]; |
| |
| if ((ptr + dlen) > end || (uptr + dlen) > uncomp_end) { |
| debug("data len %d too long", dlen); |
| return NULL; |
| } |
| |
| memcpy(uptr, ptr, dlen); |
| uptr += dlen; |
| ptr += dlen; |
| |
| } else if (dns_type == DNS_TYPE_SOA) { |
| int total_len = 0; |
| char *len_ptr; |
| |
| /* Primary name server expansion */ |
| if (!convert_label(start, end, ptr, uptr, |
| uncomp_len - (uptr - uncompressed), |
| &pos, &comp_pos)) |
| return NULL; |
| |
| total_len += comp_pos; |
| len_ptr = &uptr[-2]; |
| ptr += pos; |
| uptr += comp_pos; |
| |
| /* Responsible authority's mailbox */ |
| if (!convert_label(start, end, ptr, uptr, |
| uncomp_len - (uptr - uncompressed), |
| &pos, &comp_pos)) |
| return NULL; |
| |
| total_len += comp_pos; |
| ptr += pos; |
| uptr += comp_pos; |
| |
| /* |
| * Copy rest of the soa fields (serial number, |
| * refresh interval, retry interval, expiration |
| * limit and minimum ttl). They are 20 bytes long. |
| */ |
| if ((uptr + 20) > uncomp_end || (ptr + 20) > end) { |
| debug("soa record too long"); |
| return NULL; |
| } |
| memcpy(uptr, ptr, 20); |
| uptr += 20; |
| ptr += 20; |
| total_len += 20; |
| |
| /* |
| * Finally fix the length of the data part |
| */ |
| len_ptr[0] = total_len << 8; |
| len_ptr[1] = total_len & 0xff; |
| } |
| |
| *uncompressed_ptr = uptr; |
| } |
| |
| return ptr; |
| } |
| |
| /* |
| * removes the qualified domain name part from the given answer sections |
| * starting at 'answers', consisting of 'length' bytes. |
| * |
| * 'name' points the start of the unqualified host label including the leading |
| * length octet. |
| * |
| * returns the new (possibly shorter) length of remaining payload in the |
| * answers buffer, or a negative (errno) value to indicate error conditions. |
| */ |
| static int strip_domains(const char *name, char *answers, size_t length) |
| { |
| uint16_t data_len; |
| struct domain_rr *rr; |
| /* length of the name label including the length header octet */ |
| const size_t name_len = strlen(name); |
| const char *end = answers + length; |
| |
| while (answers < end) { |
| char *ptr = strstr(answers, name); |
| if (ptr) { |
| char *domain = ptr + name_len; |
| |
| /* this now points to the domain part length octet. */ |
| if (*domain) { |
| /* |
| * length of the rest of the labels up to the |
| * null label (zero byte). |
| */ |
| const size_t domain_len = strlen(domain); |
| char *remaining = domain + domain_len; |
| |
| /* |
| * now shift the rest of the answer sections |
| * to the left to get rid of the domain label |
| * part |
| */ |
| memmove(ptr + name_len, |
| remaining, |
| end - remaining); |
| |
| end -= domain_len; |
| length -= domain_len; |
| } |
| } |
| |
| /* skip to the next answer section */ |
| |
| /* the labels up to the root null label */ |
| answers += strlen(answers) + 1; |
| /* the fixed part of the RR */ |
| rr = (void*)answers; |
| if (answers + sizeof(*rr) > end) |
| return -EINVAL; |
| data_len = htons(rr->rdlen); |
| /* skip the rest of the RR */ |
| answers += sizeof(*rr); |
| answers += data_len; |
| } |
| |
| if (answers > end) |
| return -EINVAL; |
| |
| return length; |
| } |
| |
| /* |
| * Removes domain names from replies, if one has been appended during |
| * forwarding to the real DNS server. |
| * |
| * Returns: |
| * < 0 on error (abort processing reply) |
| * == 0 if the reply should be forwarded unmodified |
| * > 0 returns a new reply buffer in *new_reply on success. The return value |
| * indicates the new length of the data in *new_reply. |
| */ |
| static int dns_reply_fixup_domains( |
| const char *reply, size_t reply_len, |
| const size_t offset, |
| struct request_data *req, |
| char **new_reply) |
| { |
| char uncompressed[NS_MAXDNAME]; |
| char *uptr, *answers; |
| size_t fixed_len; |
| int new_an_len; |
| const struct domain_hdr *hdr = (void *)(reply + offset); |
| const char *eom = reply + reply_len; |
| uint16_t header_len = offset + DNS_HEADER_SIZE; |
| uint16_t domain_len; |
| struct qtype_qclass *qtc; |
| uint16_t dns_type; |
| uint16_t dns_class; |
| uint16_t section_counts[3]; |
| const char *ptr; |
| uint8_t host_len; |
| const char *domain; |
| |
| /* full header plus at least one byte for the hostname length */ |
| if (reply_len < header_len + 1U) |
| return -EINVAL; |
| |
| section_counts[0] = hdr->ancount; |
| section_counts[1] = hdr->nscount; |
| section_counts[2] = hdr->arcount; |
| |
| /* |
| * length octet of the hostname. |
| * ->hostname.domain.net |
| */ |
| ptr = reply + header_len; |
| host_len = *ptr; |
| domain = ptr + host_len + 1; |
| if (domain >= eom) |
| return -EINVAL; |
| |
| domain_len = host_len ? strnlen(domain, eom - domain) : 0; |
| |
| /* |
| * If the query type is anything other than A or AAAA, then bail out |
| * and pass the message as is. We only want to deal with IPv4 or IPv6 |
| * addresses. |
| */ |
| qtc = (void*)(domain + domain_len + 1); |
| if (((const char*)(qtc + 1)) > eom) |
| return -EINVAL; |
| |
| dns_type = ntohs(qtc->qtype); |
| dns_class = ntohs(qtc->qclass); |
| |
| if (domain_len == 0) { |
| /* nothing to do */ |
| return 0; |
| } |
| |
| /* TODO: This condition looks wrong. It should probably be |
| * |
| * (dns_type != A && dns_type != AAAA) || dns_class != IN |
| * |
| * doing so, however, changes the behaviour of dnsproxy, e.g. MX |
| * records will be passed back to the client, but without the |
| * adjustment of the appended domain name. |
| */ |
| if (dns_type != DNS_TYPE_A && dns_type != DNS_TYPE_AAAA && |
| dns_class != DNS_CLASS_IN) { |
| debug("Pass msg dns type %d class %d", dns_type, dns_class); |
| return 0; |
| } |
| |
| /* |
| * Remove the domain name and replace it by the end of reply. Check if |
| * the domain is really there before trying to copy the data. We also |
| * need to uncompress the answers if necessary. The domain_len can be |
| * 0 because if the original query did not contain a domain name, then |
| * we are sending two packets, first without the domain name and the |
| * second packet with domain name. The append_domain is set to true |
| * even if we sent the first packet without domain name. In this case |
| * we end up in this branch. |
| */ |
| |
| /* NOTE: length checks up and including to qtype_qclass have already |
| been done above */ |
| |
| /* |
| * First copy host (without domain name) into tmp buffer. |
| */ |
| uptr = &uncompressed[0]; |
| memcpy(uptr, ptr, host_len + 1); |
| |
| uptr[host_len + 1] = '\0'; /* host termination */ |
| uptr += host_len + 2; |
| |
| /* |
| * Copy type and class fields of the question. |
| */ |
| memcpy(uptr, qtc, sizeof(*qtc)); |
| |
| /* |
| * ptr points to answers after this |
| */ |
| ptr = (void*)(qtc + 1); |
| uptr += sizeof(*qtc); |
| answers = uptr; |
| fixed_len = answers - uncompressed; |
| |
| /* |
| * We then uncompress the result to buffer so that we can rip off the |
| * domain name part from the question. First answers, then name server |
| * (authority) information, and finally additional record info. |
| */ |
| |
| for (size_t i = 0; i < NUM_ARRAY_ELEMENTS(section_counts); i++) { |
| ptr = uncompress(ntohs(section_counts[i]), reply + offset, eom, |
| ptr, uncompressed, NS_MAXDNAME, &uptr); |
| if (!ptr) { |
| /* failed to uncompress, pass on as is |
| * (TODO: good idea?) */ |
| return 0; |
| } |
| } |
| |
| /* |
| * The uncompressed buffer now contains an almost valid response. |
| * Final step is to get rid of the domain name because at least glibc |
| * gethostbyname() implementation does extra checks and expects to |
| * find an answer without domain name if we asked a query without |
| * domain part. Note that glibc getaddrinfo() works differently and |
| * accepts FQDN in answer |
| */ |
| new_an_len = strip_domains(uncompressed, answers, uptr - answers); |
| if (new_an_len < 0) { |
| debug("Corrupted packet"); |
| return -EINVAL; |
| } |
| |
| /* |
| * Because we have now uncompressed the answers we might have to |
| * create a bigger buffer to hold all that data. |
| * |
| * TODO: only create a bigger buffer if actually necessary, pass |
| * allocation size of input buffer via additional parameter. |
| */ |
| |
| reply_len = header_len + new_an_len + fixed_len; |
| |
| *new_reply = g_try_malloc(reply_len); |
| if (!*new_reply) |
| return -ENOMEM; |
| |
| memcpy(*new_reply, reply, header_len); |
| memcpy(*new_reply + header_len, uncompressed, new_an_len + fixed_len); |
| |
| return reply_len; |
| } |
| |
| static struct request_data* lookup_request( |
| const unsigned char *reply, size_t len, int protocol) |
| { |
| const size_t offset = protocol_offset(protocol); |
| struct request_data *req; |
| struct domain_hdr *hdr = (void *)(reply + offset); |
| |
| debug("Received %zd bytes (id 0x%04x)", len, hdr->id); |
| |
| if (len < DNS_HEADER_SIZE + offset) |
| return NULL; |
| |
| req = find_request(hdr->id); |
| |
| if (!req) |
| return NULL; |
| |
| debug("req %p dstid 0x%04x altid 0x%04x rcode %d", |
| req, req->dstid, req->altid, hdr->rcode); |
| |
| req->numresp++; |
| |
| return req; |
| } |
| |
| static int forward_dns_reply(char *reply, size_t reply_len, int protocol, |
| struct server_data *data, struct request_data *req) |
| { |
| const size_t offset = protocol_offset(protocol); |
| struct domain_hdr *hdr = (void *)(reply + offset); |
| int err, sk; |
| |
| /* replace with original request ID from our client */ |
| hdr->id = req->srcid; |
| |
| if (hdr->rcode == ns_r_noerror || !req->resp) { |
| /* |
| * If the domain name was appended remove it before forwarding |
| * the reply. If there were more than one question, then this |
| * domain name ripping can be hairy so avoid that and bail out |
| * in that that case. |
| * |
| * The reason we are doing this magic is that if the user's |
| * DNS client tries to resolv hostname without domain part, it |
| * also expects to get the result without a domain name part. |
| */ |
| char *new_reply = NULL; |
| |
| if (req->append_domain && ntohs(hdr->qdcount) == 1) { |
| const int fixup_res = dns_reply_fixup_domains( |
| reply, reply_len, |
| offset, req, &new_reply); |
| if (fixup_res < 0) { |
| /* error occured */ |
| return fixup_res; |
| } else if (fixup_res > 0 && new_reply) { |
| /* new reply length */ |
| reply_len = fixup_res; |
| reply = new_reply; |
| } else { |
| /* keep message as is */ |
| } |
| } |
| |
| g_free(req->resp); |
| req->resplen = 0; |
| |
| req->resp = g_try_malloc(reply_len); |
| if (!req->resp) |
| return -ENOMEM; |
| |
| memcpy(req->resp, reply, reply_len); |
| req->resplen = reply_len; |
| |
| cache_update(data, (unsigned char*)reply, reply_len); |
| |
| g_free(new_reply); |
| } |
| |
| if (req->numresp < req->numserv) { |
| if (hdr->rcode > ns_r_noerror) { |
| return -EINVAL; |
| } else if (hdr->ancount == 0 && req->append_domain) { |
| return -EINVAL; |
| } |
| } |
| |
| request_list = g_slist_remove(request_list, req); |
| |
| if (protocol == IPPROTO_UDP) { |
| sk = get_req_udp_socket(req); |
| if (sk < 0) { |
| errno = -EIO; |
| err = -EIO; |
| } else |
| err = sendto(sk, req->resp, req->resplen, 0, |
| &req->sa, req->sa_len); |
| } else { |
| const uint16_t tcp_len = htons(req->resplen - DNS_HEADER_TCP_EXTRA_BYTES); |
| /* correct TCP message length */ |
| memcpy(req->resp, &tcp_len, sizeof(tcp_len)); |
| sk = req->client_sk; |
| err = send(sk, req->resp, req->resplen, MSG_NOSIGNAL); |
| } |
| |
| if (err < 0) |
| debug("Cannot send msg, sk %d proto %d errno %d/%s", sk, |
| protocol, errno, strerror(errno)); |
| else |
| debug("proto %d sent %d bytes to %d", protocol, err, sk); |
| |
| return err; |
| } |
| |
| static void server_destroy_socket(struct server_data *data) |
| { |
| debug("index %d server %s proto %d", data->index, |
| data->server, data->protocol); |
| |
| if (data->watch > 0) { |
| g_source_remove(data->watch); |
| data->watch = 0; |
| } |
| |
| if (data->timeout > 0) { |
| g_source_remove(data->timeout); |
| data->timeout = 0; |
| } |
| |
| if (data->channel) { |
| g_io_channel_shutdown(data->channel, TRUE, NULL); |
| g_io_channel_unref(data->channel); |
| data->channel = NULL; |
| } |
| |
| g_free(data->incoming_reply); |
| data->incoming_reply = NULL; |
| } |
| |
| static void destroy_server(struct server_data *server) |
| { |
| debug("index %d server %s sock %d", server->index, server->server, |
| server->channel ? |
| g_io_channel_unix_get_fd(server->channel): -1); |
| |
| server_list = g_slist_remove(server_list, server); |
| server_destroy_socket(server); |
| |
| if (server->protocol == IPPROTO_UDP && server->enabled) |
| debug("Removing DNS server %s", server->server); |
| |
| g_free(server->server); |
| g_list_free_full(server->domains, g_free); |
| g_free(server->server_addr); |
| |
| /* |
| * We do not remove cache right away but delay it few seconds. |
| * The idea is that when IPv6 DNS server is added via RDNSS, it has a |
| * lifetime. When the lifetime expires we decrease the refcount so it |
| * is possible that the cache is then removed. Because a new DNS server |
| * is usually created almost immediately we would then loose the cache |
| * without any good reason. The small delay allows the new RDNSS to |
| * create a new DNS server instance and the refcount does not go to 0. |
| */ |
| if (cache && !cache_timer) |
| cache_timer = g_timeout_add_seconds(3, try_remove_cache, NULL); |
| |
| g_free(server); |
| } |
| |
| static gboolean udp_server_event(GIOChannel *channel, GIOCondition condition, |
| gpointer user_data) |
| { |
| unsigned char buf[4096]; |
| int sk, res; |
| ssize_t len; |
| struct server_data *data = user_data; |
| struct request_data *req; |
| |
| if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) { |
| connman_error("Error with UDP server %s", data->server); |
| server_destroy_socket(data); |
| return FALSE; |
| } |
| |
| sk = g_io_channel_unix_get_fd(channel); |
| len = recv(sk, buf, sizeof(buf), 0); |
| |
| if (len <= 0) |
| return TRUE; |
| |
| req = lookup_request(buf, len, IPPROTO_UDP); |
| |
| if (!req) |
| /* invalid / corrupt request */ |
| return TRUE; |
| |
| res = forward_dns_reply((char*)buf, len, IPPROTO_UDP, data, req); |
| |
| /* on success or no further responses are expected, destroy the req */ |
| if (res == 0 || req->numresp >= req->numserv) |
| destroy_request_data(req); |
| |
| return TRUE; |
| } |
| |
| static gboolean tcp_server_event(GIOChannel *channel, GIOCondition condition, |
| gpointer user_data) |
| { |
| struct request_data *req; |
| struct server_data *server = user_data; |
| int sk = g_io_channel_unix_get_fd(channel); |
| if (sk == 0) |
| return FALSE; |
| |
| if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) { |
| GSList *list; |
| hangup: |
| debug("TCP server channel closed, sk %d", sk); |
| |
| /* |
| * Discard any partial response which is buffered; better |
| * to get a proper response from a working server. |
| */ |
| g_free(server->incoming_reply); |
| server->incoming_reply = NULL; |
| |
| list = request_list; |
| while (list) { |
| struct domain_hdr *hdr; |
| req = list->data; |
| list = list->next; |
| |
| if (req->protocol == IPPROTO_UDP) |
| continue; |
| else if (!req->request) |
| continue; |
| |
| /* |
| * If we're not waiting for any further response |
| * from another name server, then we send an error |
| * response to the client. |
| */ |
| if (req->numserv && --(req->numserv)) |
| continue; |
| |
| hdr = (void *)(req->request + DNS_HEADER_TCP_EXTRA_BYTES); |
| hdr->id = req->srcid; |
| send_response(req->client_sk, req->request, |
| req->request_len, NULL, 0, IPPROTO_TCP); |
| |
| request_list = g_slist_remove(request_list, req); |
| } |
| |
| destroy_server(server); |
| |
| return FALSE; |
| } |
| |
| if ((condition & G_IO_OUT) && !server->connected) { |
| bool no_request_sent = true; |
| struct server_data *udp_server = find_server( |
| server->index, server->server, |
| IPPROTO_UDP); |
| if (udp_server) { |
| for (GList *domains = udp_server->domains; domains; |
| domains = domains->next) { |
| const char *dom = domains->data; |
| |
| debug("Adding domain %s to %s", |
| dom, server->server); |
| |
| server->domains = g_list_append(server->domains, |
| g_strdup(dom)); |
| } |
| } |
| |
| /* |
| * Remove the G_IO_OUT flag from the watch, otherwise we end |
| * up in a busy loop, because the socket is constantly writable. |
| * |
| * There seems to be no better way in g_io to do that than |
| * re-adding the watch. |
| */ |
| g_source_remove(server->watch); |
| server->watch = g_io_add_watch(server->channel, |
| G_IO_IN | G_IO_HUP | G_IO_NVAL | G_IO_ERR, |
| tcp_server_event, server); |
| |
| server->connected = true; |
| server_list = g_slist_append(server_list, server); |
| |
| /* don't advance the list in the for loop, because we might |
| * need to delete elements while iterating through it */ |
| for (GSList *list = request_list; list; ) { |
| int status; |
| req = list->data; |
| |
| if (req->protocol == IPPROTO_UDP) { |
| list = list->next; |
| continue; |
| } |
| |
| debug("Sending req %s over TCP", (char *)req->name); |
| |
| status = ns_resolv(server, req, |
| req->request, req->name); |
| if (status > 0) { |
| /* |
| * A cached result was sent, |
| * so the request can be released |
| */ |
| list = list->next; |
| request_list = g_slist_remove(request_list, req); |
| destroy_request_data(req); |
| continue; |
| } else if (status < 0) { |
| list = list->next; |
| continue; |
| } |
| |
| no_request_sent = false; |
| |
| if (req->timeout > 0) |
| g_source_remove(req->timeout); |
| |
| req->timeout = g_timeout_add_seconds(30, |
| request_timeout, req); |
| list = list->next; |
| } |
| |
| if (no_request_sent) { |
| destroy_server(server); |
| return FALSE; |
| } |
| |
| } else if (condition & G_IO_IN) { |
| struct partial_reply *reply = server->incoming_reply; |
| int bytes_recv; |
| int res; |
| |
| if (!reply) { |
| uint16_t reply_len; |
| size_t bytes_len; |
| |
| bytes_recv = recv(sk, &reply_len, sizeof(reply_len), MSG_PEEK); |
| if (!bytes_recv) { |
| goto hangup; |
| } else if (bytes_recv < 0) { |
| if (errno == EAGAIN || errno == EWOULDBLOCK) |
| return TRUE; |
| |
| connman_error("DNS proxy error %s", |
| strerror(errno)); |
| goto hangup; |
| } |
| |
| bytes_len = bytes_recv; |
| if (bytes_len < sizeof(reply_len)) |
| return TRUE; |
| |
| /* the header contains the length of the message |
| * excluding the two length bytes */ |
| reply_len = ntohs(reply_len) + DNS_HEADER_TCP_EXTRA_BYTES; |
| |
| debug("TCP reply %d bytes from %d", reply_len, sk); |
| |
| reply = g_try_malloc(sizeof(*reply) + reply_len + 2); |
| if (!reply) |
| return TRUE; |
| |
| reply->len = reply_len; |
| /* we only peeked the two length bytes, so we have to |
| receive the complete message below proper. */ |
| reply->received = 0; |
| |
| server->incoming_reply = reply; |
| } |
| |
| while (reply->received < reply->len) { |
| bytes_recv = recv(sk, reply->buf + reply->received, |
| reply->len - reply->received, 0); |
| if (!bytes_recv) { |
| connman_error("DNS proxy TCP disconnect"); |
| break; |
| } else if (bytes_recv < 0) { |
| if (errno == EAGAIN || errno == EWOULDBLOCK) |
| return TRUE; |
| |
| connman_error("DNS proxy error %s", |
| strerror(errno)); |
| break; |
| } |
| reply->received += bytes_recv; |
| } |
| |
| req = lookup_request(reply->buf, reply->received, IPPROTO_TCP); |
| |
| if (!req) |
| /* invalid / corrupt request */ |
| return TRUE; |
| |
| res = forward_dns_reply((char*)reply->buf, reply->received, IPPROTO_TCP, server, req); |
| |
| g_free(reply); |
| server->incoming_reply = NULL; |
| |
| /* on success or if no further responses are expected close |
| * connection */ |
| if (res == 0 || req->numresp >= req->numserv) { |
| destroy_request_data(req); |
| destroy_server(server); |
| return FALSE; |
| } |
| |
| /* |
| * keep the TCP connection open, there are more |
| * requests to be answered |
| */ |
| return TRUE; |
| } |
| |
| return TRUE; |
| } |
| |
| static gboolean tcp_idle_timeout(gpointer user_data) |
| { |
| struct server_data *server = user_data; |
| |
| debug("\n"); |
| |
| if (!server) |
| return FALSE; |
| |
| destroy_server(server); |
| |
| return FALSE; |
| } |
| |
| static int server_create_socket(struct server_data *data) |
| { |
| int err; |
| char *interface; |
| int sk = socket(data->server_addr->sa_family, |
| data->protocol == IPPROTO_TCP ? SOCK_STREAM : SOCK_DGRAM, |
| data->protocol); |
| |
| debug("index %d server %s proto %d", data->index, |
| data->server, data->protocol); |
| |
| if (sk < 0) { |
| err = errno; |
| connman_error("Failed to create server %s socket", |
| data->server); |
| server_destroy_socket(data); |
| return -err; |
| } |
| |
| debug("sk %d", sk); |
| |
| interface = connman_inet_ifname(data->index); |
| if (interface) { |
| if (setsockopt(sk, SOL_SOCKET, SO_BINDTODEVICE, |
| interface, |
| strlen(interface) + 1) < 0) { |
| err = errno; |
| connman_error("Failed to bind server %s " |
| "to interface %s", |
| data->server, interface); |
| close(sk); |
| server_destroy_socket(data); |
| g_free(interface); |
| return -err; |
| } |
| g_free(interface); |
| } |
| |
| data->channel = g_io_channel_unix_new(sk); |
| if (!data->channel) { |
| connman_error("Failed to create server %s channel", |
| data->server); |
| close(sk); |
| server_destroy_socket(data); |
| return -ENOMEM; |
| } |
| |
| g_io_channel_set_close_on_unref(data->channel, TRUE); |
| |
| if (data->protocol == IPPROTO_TCP) { |
| g_io_channel_set_flags(data->channel, G_IO_FLAG_NONBLOCK, NULL); |
| data->watch = g_io_add_watch(data->channel, |
| G_IO_OUT | G_IO_IN | G_IO_HUP | G_IO_NVAL | G_IO_ERR, |
| tcp_server_event, data); |
| data->timeout = g_timeout_add_seconds(30, tcp_idle_timeout, |
| data); |
| } else |
| data->watch = g_io_add_watch(data->channel, |
| G_IO_IN | G_IO_NVAL | G_IO_ERR | G_IO_HUP, |
| udp_server_event, data); |
| |
| if (connect(sk, data->server_addr, data->server_addr_len) < 0) { |
| err = errno; |
| |
| if ((data->protocol == IPPROTO_TCP && errno != EINPROGRESS) || |
| data->protocol == IPPROTO_UDP) { |
| |
| connman_error("Failed to connect to server %s", |
| data->server); |
| server_destroy_socket(data); |
| return -err; |
| } |
| } |
| |
| create_cache(); |
| |
| return 0; |
| } |
| |
| static void enable_fallback(bool enable) |
| { |
| for (GSList *list = server_list; list; list = list->next) { |
| struct server_data *data = list->data; |
| |
| if (data->index != -1) |
| continue; |
| |
| if (enable) |
| DBG("Enabling fallback DNS server %s", data->server); |
| else |
| DBG("Disabling fallback DNS server %s", data->server); |
| |
| data->enabled = enable; |
| } |
| } |
| |
| static unsigned int get_enabled_server_number(void) |
| { |
| GSList *list; |
| unsigned int result = 0; |
| |
| for (list = server_list; list; list = list->next) { |
| struct server_data *data = list->data; |
| |
| if (data->index != -1 && data->enabled == true) |
| result++; |
| } |
| return result; |
| } |
| |
| static struct server_data *create_server(int index, |
| const char *domain, const char *server, |
| int protocol) |
| { |
| struct server_data *data = g_try_new0(struct server_data, 1); |
| struct addrinfo hints, *rp; |
| int ret; |
| |
| DBG("index %d server %s", index, server); |
| |
| if (!data) { |
| connman_error("Failed to allocate server %s data", server); |
| return NULL; |
| } |
| |
| data->index = index; |
| if (domain) |
| data->domains = g_list_append(data->domains, g_strdup(domain)); |
| data->server = g_strdup(server); |
| data->protocol = protocol; |
| |
| memset(&hints, 0, sizeof(hints)); |
| hints.ai_socktype = socket_type(protocol, 0); |
| hints.ai_family = AF_UNSPEC; |
| hints.ai_flags = AI_NUMERICSERV | AI_NUMERICHOST; |
| |
| ret = getaddrinfo(data->server, "53", &hints, &rp); |
| if (ret) { |
| connman_error("Failed to parse server %s address: %s\n", |
| data->server, gai_strerror(ret)); |
| destroy_server(data); |
| return NULL; |
| } |
| |
| /* Do not blindly copy this code elsewhere; it doesn't loop over the |
| results using ->ai_next as it should. That's OK in *this* case |
| because it was a numeric lookup; we *know* there's only one. */ |
| |
| data->server_addr_len = rp->ai_addrlen; |
| |
| switch (rp->ai_family) { |
| case AF_INET: |
| data->server_addr = (struct sockaddr *) |
| g_try_new0(struct sockaddr_in, 1); |
| break; |
| case AF_INET6: |
| data->server_addr = (struct sockaddr *) |
| g_try_new0(struct sockaddr_in6, 1); |
| break; |
| default: |
| connman_error("Wrong address family %d", rp->ai_family); |
| break; |
| } |
| if (!data->server_addr) { |
| freeaddrinfo(rp); |
| destroy_server(data); |
| return NULL; |
| } |
| memcpy(data->server_addr, rp->ai_addr, rp->ai_addrlen); |
| freeaddrinfo(rp); |
| |
| if (server_create_socket(data) != 0) { |
| destroy_server(data); |
| return NULL; |
| } |
| |
| if (protocol == IPPROTO_UDP) { |
| if (__connman_service_index_is_default(data->index) || |
| __connman_service_index_is_split_routing( |
| data->index)) { |
| data->enabled = true; |
| DBG("Adding DNS server %s", data->server); |
| |
| enable_fallback(false); |
| } else if (data->index == -1 && get_enabled_server_number() == 0) { |
| data->enabled = true; |
| DBG("Adding fallback DNS server %s", data->server); |
| } |
| |
| server_list = g_slist_append(server_list, data); |
| } |
| |
| return data; |
| } |
| |
| static bool resolv(struct request_data *req, |
| gpointer request, gpointer name) |
| { |
| for (GSList *list = server_list; list; list = list->next) { |
| struct server_data *data = list->data; |
| |
| if (data->protocol == IPPROTO_TCP) { |
| DBG("server %s ignored proto TCP", data->server); |
| continue; |
| } |
| |
| debug("server %s enabled %d", data->server, data->enabled); |
| |
| if (!data->enabled) |
| continue; |
| |
| if (!data->channel && data->protocol == IPPROTO_UDP) { |
| if (server_create_socket(data) < 0) { |
| DBG("socket creation failed while resolving"); |
| continue; |
| } |
| } |
| |
| if (ns_resolv(data, req, request, name) > 0) |
| return true; |
| } |
| |
| return false; |
| } |
| |
| static void update_domain(int index, const char *domain, bool append) |
| { |
| DBG("index %d domain %s", index, domain); |
| |
| if (!domain) |
| return; |
| |
| for (GSList *list = server_list; list; list = list->next) { |
| struct server_data *data = list->data; |
| char *dom = NULL; |
| bool dom_found = false; |
| |
| if (data->index < 0) |
| continue; |
| else if (data->index != index) |
| continue; |
| |
| for (GList *dom_list = data->domains; dom_list; |
| dom_list = dom_list->next) { |
| dom = dom_list->data; |
| |
| if (g_str_equal(dom, domain)) { |
| dom_found = true; |
| break; |
| } |
| } |
| |
| if (!dom_found && append) { |
| data->domains = |
| g_list_append(data->domains, g_strdup(domain)); |
| } else if (dom_found && !append) { |
| data->domains = |
| g_list_remove(data->domains, dom); |
| g_free(dom); |
| } |
| } |
| } |
| |
| static void append_domain(int index, const char *domain) |
| { |
| update_domain(index, domain, true); |
| } |
| |
| static void remove_domain(int index, const char *domain) |
| { |
| update_domain(index, domain, false); |
| } |
| |
| static void flush_requests(struct server_data *server) |
| { |
| GSList *list = request_list; |
| while (list) { |
| struct request_data *req = list->data; |
| |
| list = list->next; |
| |
| if (ns_resolv(server, req, req->request, req->name)) { |
| /* |
| * A cached result was sent, |
| * so the request can be released |
| */ |
| request_list = |
| g_slist_remove(request_list, req); |
| destroy_request_data(req); |
| continue; |
| } |
| |
| if (req->timeout > 0) |
| g_source_remove(req->timeout); |
| |
| req->timeout = g_timeout_add_seconds(5, request_timeout, req); |
| } |
| } |
| |
| int __connman_dnsproxy_append(int index, const char *domain, |
| const char *server) |
| { |
| struct server_data *data; |
| DBG("index %d server %s", index, server); |
| |
| if (!server) { |
| if (!domain) { |
| return -EINVAL; |
| } else { |
| append_domain(index, domain); |
| return 0; |
| } |
| } |
| |
| if (g_str_equal(server, "127.0.0.1")) |
| return -ENODEV; |
| else if (g_str_equal(server, "::1")) |
| return -ENODEV; |
| |
| data = find_server(index, server, IPPROTO_UDP); |
| if (data) { |
| append_domain(index, domain); |
| return 0; |
| } |
| |
| data = create_server(index, domain, server, IPPROTO_UDP); |
| if (!data) |
| return -EIO; |
| |
| flush_requests(data); |
| |
| return 0; |
| } |
| |
| static void remove_server(int index, const char *server, int protocol) |
| { |
| struct server_data *data; |
| |
| data = find_server(index, server, protocol); |
| if (!data) |
| return; |
| |
| destroy_server(data); |
| |
| if (get_enabled_server_number() == 0) |
| enable_fallback(true); |
| } |
| |
| int __connman_dnsproxy_remove(int index, const char *domain, |
| const char *server) |
| { |
| DBG("index %d server %s", index, server); |
| |
| if (!server) { |
| if (!domain) { |
| return -EINVAL; |
| } else { |
| remove_domain(index, domain); |
| return 0; |
| } |
| } |
| |
| if (g_str_equal(server, "127.0.0.1")) |
| return -ENODEV; |
| else if (g_str_equal(server, "::1")) |
| return -ENODEV; |
| |
| remove_server(index, server, IPPROTO_UDP); |
| remove_server(index, server, IPPROTO_TCP); |
| |
| return 0; |
| } |
| |
| static void dnsproxy_offline_mode(bool enabled) |
| { |
| DBG("enabled %d", enabled); |
| |
| for (GSList *list = server_list; list; list = list->next) { |
| struct server_data *data = list->data; |
| |
| if (!enabled) { |
| DBG("Enabling DNS server %s", data->server); |
| data->enabled = true; |
| cache_invalidate(); |
| cache_refresh(); |
| } else { |
| DBG("Disabling DNS server %s", data->server); |
| data->enabled = false; |
| cache_invalidate(); |
| } |
| } |
| } |
| |
| static void dnsproxy_default_changed(struct connman_service *service) |
| { |
| bool any_server_enabled = false; |
| int index, vpn_index; |
| |
| DBG("service %p", service); |
| |
| /* DNS has changed, invalidate the cache */ |
| cache_invalidate(); |
| |
| if (!service) { |
| /* When no services are active, then disable DNS proxying */ |
| dnsproxy_offline_mode(true); |
| return; |
| } |
| |
| index = __connman_service_get_index(service); |
| if (index < 0) |
| return; |
| |
| /* |
| * In case non-split-routed VPN is set as split routed the DNS servers |
| * the VPN must be enabled as well, when the transport becomes the |
| * default service. |
| */ |
| vpn_index = __connman_gateway_get_vpn_index(index); |
| |
| for (GSList *list = server_list; list; list = list->next) { |
| struct server_data *data = list->data; |
| |
| if (data->index == index) { |
| DBG("Enabling DNS server %s", data->server); |
| data->enabled = true; |
| any_server_enabled = true; |
| } else if (data->index == vpn_index) { |
| DBG("Enabling DNS server of VPN %s", data->server); |
| data->enabled = true; |
| } else { |
| DBG("Disabling DNS server %s", data->server); |
| data->enabled = false; |
| } |
| } |
| |
| if (!any_server_enabled) |
| enable_fallback(true); |
| |
| cache_refresh(); |
| } |
| |
| static void dnsproxy_service_state_changed(struct connman_service *service, |
| enum connman_service_state state) |
| { |
| GSList *list; |
| int index; |
| |
| switch (state) { |
| case CONNMAN_SERVICE_STATE_DISCONNECT: |
| case CONNMAN_SERVICE_STATE_IDLE: |
| break; |
| case CONNMAN_SERVICE_STATE_ASSOCIATION: |
| case CONNMAN_SERVICE_STATE_CONFIGURATION: |
| case CONNMAN_SERVICE_STATE_FAILURE: |
| case CONNMAN_SERVICE_STATE_ONLINE: |
| case CONNMAN_SERVICE_STATE_READY: |
| case CONNMAN_SERVICE_STATE_UNKNOWN: |
| return; |
| } |
| |
| index = __connman_service_get_index(service); |
| list = server_list; |
| |
| while (list) { |
| struct server_data *data = list->data; |
| |
| /* Get next before the list is changed by destroy_server() */ |
| list = list->next; |
| |
| if (data->index == index) { |
| DBG("removing server data of index %d", index); |
| destroy_server(data); |
| } |
| } |
| } |
| |
| static const struct connman_notifier dnsproxy_notifier = { |
| .name = "dnsproxy", |
| .default_changed = dnsproxy_default_changed, |
| .offline_mode = dnsproxy_offline_mode, |
| .service_state_changed = dnsproxy_service_state_changed, |
| }; |
| |
| /* |
| * Parses the given request buffer. `buf´ is expected to be the start of the |
| * domain_hdr structure i.e. the TCP length header is not handled by this |
| * function. |
| * Returns the ascii string dot representation of the query in `name´, which |
| * must be able to hold `size´ bytes. |
| * |
| * Returns < 0 on error (errno) or zero on success. |
| */ |
| static int parse_request(unsigned char *buf, size_t len, |
| char *name, size_t size) |
| { |
| static const unsigned char OPT_EDNS0_TYPE[2] = { 0x00, 0x29 }; |
| struct domain_hdr *hdr = (void *) buf; |
| uint16_t qdcount, ancount, nscount, arcount; |
| unsigned char *ptr = buf + DNS_HEADER_SIZE; |
| size_t remain = len - DNS_HEADER_SIZE; |
| size_t used = 0; |
| |
| if (len < DNS_HEADER_SIZE + DNS_QTYPE_QCLASS_SIZE) { |
| DBG("Dropped DNS request with short length %zd", len); |
| return -EINVAL; |
| } |
| |
| if (!name || !size) |
| return -EINVAL; |
| |
| qdcount = ntohs(hdr->qdcount); |
| ancount = ntohs(hdr->ancount); |
| nscount = ntohs(hdr->nscount); |
| arcount = ntohs(hdr->arcount); |
| |
| if (hdr->qr || qdcount != 1 || ancount || nscount) { |
| DBG("Dropped DNS request with bad flags/counts qr %d " |
| "with len %zd qdcount %d ancount %d nscount %d", |
| hdr->qr, len, qdcount, ancount, nscount); |
| |
| return -EINVAL; |
| } |
| |
| debug("id 0x%04x qr %d opcode %d qdcount %d arcount %d", |
| hdr->id, hdr->qr, hdr->opcode, |
| qdcount, arcount); |
| |
| name[0] = '\0'; |
| |
| /* parse DNS query string into `name' out parameter */ |
| while (remain > 0) { |
| uint8_t label_len = *ptr; |
| |
| if (label_len == 0x00) { |
| struct qtype_qclass *q = (struct qtype_qclass *)(ptr + 1); |
| uint16_t class; |
| |
| if (remain < sizeof(*q)) { |
| DBG("Dropped malformed DNS query"); |
| return -EINVAL; |
| } |
| |
| class = ntohs(q->qclass); |
| if (class != DNS_CLASS_IN && class != DNS_CLASS_ANY) { |
| DBG("Dropped non-IN DNS class %d", class); |
| return -EINVAL; |
| } |
| |
| ptr += sizeof(*q) + 1; |
| remain -= (sizeof(*q) + 1); |
| break; |
| } |
| |
| if (used + label_len + 1 > size) |
| return -ENOBUFS; |
| |
| strncat(name, (char *) (ptr + 1), label_len); |
| strcat(name, "."); |
| |
| used += label_len + 1; |
| ptr += label_len + 1; |
| remain -= label_len + 1; |
| } |
| |
| if (arcount && remain >= DNS_RR_SIZE + 1 && !ptr[0] && |
| ptr[1] == OPT_EDNS0_TYPE[0] && ptr[2] == OPT_EDNS0_TYPE[1]) { |
| struct domain_rr *edns0 = (struct domain_rr *)(ptr + 1); |
| |
| DBG("EDNS0 buffer size %u", ntohs(edns0->class)); |
| } else if (!arcount && remain) { |
| DBG("DNS request with %zd garbage bytes", remain); |
| } |
| |
| debug("query %s", name); |
| |
| return 0; |
| } |
| |
| static void client_reset(struct tcp_partial_client_data *client) |
| { |
| if (!client) |
| return; |
| |
| if (client->channel) { |
| debug("client %d closing", |
| g_io_channel_unix_get_fd(client->channel)); |
| |
| g_io_channel_unref(client->channel); |
| client->channel = NULL; |
| } |
| |
| if (client->watch > 0) { |
| g_source_remove(client->watch); |
| client->watch = 0; |
| } |
| |
| if (client->timeout > 0) { |
| g_source_remove(client->timeout); |
| client->timeout = 0; |
| } |
| |
| g_free(client->buf); |
| client->buf = NULL; |
| |
| client->buf_end = 0; |
| } |
| |
| static size_t get_msg_len(const unsigned char *buf) |
| { |
| return buf[0]<<8 | buf[1]; |
| } |
| |
| static bool read_tcp_data(struct tcp_partial_client_data *client, |
| void *client_addr, socklen_t client_addr_len, |
| int read_len) |
| { |
| char query[TCP_MAX_BUF_LEN]; |
| struct request_data *req; |
| struct domain_hdr *hdr; |
| int client_sk = g_io_channel_unix_get_fd(client->channel); |
| int err; |
| size_t msg_len; |
| bool waiting_for_connect = false; |
| uint16_t qtype = 0; |
| struct cache_entry *entry; |
| |
| if (read_len == 0) { |
| debug("client %d closed, pending %d bytes", |
| client_sk, client->buf_end); |
| g_hash_table_remove(partial_tcp_req_table, |
| GINT_TO_POINTER(client_sk)); |
| return false; |
| } |
| |
| debug("client %d received %d bytes", client_sk, read_len); |
| |
| client->buf_end += read_len; |
| |
| /* we need at least the message length header */ |
| if (client->buf_end < DNS_HEADER_TCP_EXTRA_BYTES) |
| return true; |
| |
| msg_len = get_msg_len(client->buf); |
| if (msg_len > TCP_MAX_BUF_LEN) { |
| debug("client %d sent too much data %zd", client_sk, msg_len); |
| g_hash_table_remove(partial_tcp_req_table, |
| GINT_TO_POINTER(client_sk)); |
| return false; |
| } |
| |
| read_another: |
| debug("client %d msg len %zd end %d past end %zd", client_sk, msg_len, |
| client->buf_end, client->buf_end - (msg_len + 2)); |
| |
| if (client->buf_end < (msg_len + 2)) { |
| debug("client %d still missing %zd bytes", |
| client_sk, |
| msg_len + 2 - client->buf_end); |
| return true; |
| } |
| |
| debug("client %d all data %zd received", client_sk, msg_len); |
| |
| err = parse_request(client->buf + DNS_HEADER_TCP_EXTRA_BYTES, |
| msg_len, query, sizeof(query)); |
| if (err < 0 || (g_slist_length(server_list) == 0)) { |
| send_response(client_sk, client->buf, |
| msg_len + DNS_HEADER_TCP_EXTRA_BYTES, |
| NULL, 0, IPPROTO_TCP); |
| return true; |
| } |
| |
| req = g_try_new0(struct request_data, 1); |
| if (!req) |
| return true; |
| |
| memcpy(&req->sa, client_addr, client_addr_len); |
| req->sa_len = client_addr_len; |
| req->client_sk = client_sk; |
| req->protocol = IPPROTO_TCP; |
| req->family = client->family; |
| |
| hdr = (void*)(client->buf + DNS_HEADER_TCP_EXTRA_BYTES); |
| |
| memcpy(&req->srcid, &hdr->id, sizeof(req->srcid)); |
| req->dstid = get_id(); |
| req->altid = get_id(); |
| req->request_len = msg_len + DNS_HEADER_TCP_EXTRA_BYTES; |
| |
| /* replace ID the request for forwarding */ |
| memcpy(&hdr->id, &req->dstid, sizeof(hdr->id)); |
| |
| req->numserv = 0; |
| req->ifdata = client->ifdata; |
| req->append_domain = false; |
| |
| /* |
| * Check if the answer is found in the cache before |
| * creating sockets to the server. |
| */ |
| entry = cache_check(client->buf, &qtype, IPPROTO_TCP); |
| if (entry) { |
| struct cache_data *data; |
| |
| debug("cache hit %s type %s", query, |
| qtype == DNS_TYPE_A ? "A" : "AAAA"); |
| |
| data = qtype == DNS_TYPE_A ? entry->ipv4 : entry->ipv6; |
| |
| if (data) { |
| int ttl_left = data->valid_until - time(NULL); |
| entry->hits++; |
| |
| send_cached_response(client_sk, data->data, |
| data->data_len, NULL, 0, IPPROTO_TCP, |
| req->srcid, data->answers, ttl_left); |
| |
| g_free(req); |
| goto out; |
| } else |
| debug("data missing, ignoring cache for this query"); |
| } |
| |
| for (GSList *list = server_list; list; list = list->next) { |
| struct server_data *data = list->data; |
| |
| if (data->protocol != IPPROTO_UDP || !data->enabled) |
| continue; |
| |
| if (!create_server(data->index, NULL, data->server, |
| IPPROTO_TCP)) |
| continue; |
| |
| waiting_for_connect = true; |
| } |
| |
| if (!waiting_for_connect) { |
| /* No server is waiting for connect */ |
| send_response(client_sk, client->buf, |
| req->request_len, NULL, 0, IPPROTO_TCP); |
| g_free(req); |
| return true; |
| } |
| |
| /* |
| * The server is not connected yet. |
| * Copy the relevant buffers. |
| * The request will actually be sent once we're |
| * properly connected over TCP to the nameserver. |
| */ |
| req->request = g_try_malloc0(req->request_len); |
| if (!req->request) { |
| send_response(client_sk, client->buf, |
| req->request_len, NULL, 0, IPPROTO_TCP); |
| g_free(req); |
| goto out; |
| } |
| memcpy(req->request, client->buf, req->request_len); |
| |
| req->name = g_try_malloc0(sizeof(query)); |
| if (!req->name) { |
| send_response(client_sk, client->buf, |
| req->request_len, NULL, 0, IPPROTO_TCP); |
| g_free(req->request); |
| g_free(req); |
| goto out; |
| } |
| memcpy(req->name, query, sizeof(query)); |
| |
| req->timeout = g_timeout_add_seconds(30, request_timeout, req); |
| |
| request_list = g_slist_append(request_list, req); |
| |
| out: |
| if (client->buf_end > (msg_len + DNS_HEADER_TCP_EXTRA_BYTES)) { |
| debug("client %d buf %p -> %p end %d len %d new %zd", |
| client_sk, |
| client->buf + msg_len + 2, |
| client->buf, client->buf_end, |
| TCP_MAX_BUF_LEN - client->buf_end, |
| client->buf_end - (msg_len + 2)); |
| memmove(client->buf, client->buf + msg_len + 2, |
| TCP_MAX_BUF_LEN - client->buf_end); |
| client->buf_end = client->buf_end - (msg_len + 2); |
| |
| /* |
| * If we have a full message waiting, just read it |
| * immediately. |
| */ |
| msg_len = get_msg_len(client->buf); |
| if ((msg_len + 2) == client->buf_end) { |
| debug("client %d reading another %zd bytes", client_sk, |
| msg_len + 2); |
| goto read_another; |
| } |
| } else { |
| debug("client %d clearing reading buffer", client_sk); |
| |
| client->buf_end = 0; |
| memset(client->buf, 0, TCP_MAX_BUF_LEN); |
| |
| /* |
| * We received all the packets from client so we must also |
| * remove the timeout handler here otherwise we might get |
| * timeout while waiting the results from server. |
| */ |
| g_source_remove(client->timeout); |
| client->timeout = 0; |
| } |
| |
| return true; |
| } |
| |
| static gboolean tcp_client_event(GIOChannel *channel, GIOCondition condition, |
| gpointer user_data) |
| { |
| struct tcp_partial_client_data *client = user_data; |
| int client_sk = g_io_channel_unix_get_fd(channel); |
| int len; |
| struct sockaddr_in6 client_addr6; |
| socklen_t client_addr6_len = sizeof(client_addr6); |
| struct sockaddr_in client_addr4; |
| socklen_t client_addr4_len = sizeof(client_addr4); |
| void *client_addr; |
| socklen_t *client_addr_len; |
| |
| if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) { |
| g_hash_table_remove(partial_tcp_req_table, |
| GINT_TO_POINTER(client_sk)); |
| |
| connman_error("Error with TCP client %d channel", client_sk); |
| return FALSE; |
| } |
| |
| switch (client->family) { |
| case AF_INET: |
| client_addr = &client_addr4; |
| client_addr_len = &client_addr4_len; |
| break; |
| case AF_INET6: |
| client_addr = &client_addr6; |
| client_addr_len = &client_addr6_len; |
| break; |
| default: |
| g_hash_table_remove(partial_tcp_req_table, |
| GINT_TO_POINTER(client_sk)); |
| connman_error("client %p corrupted", client); |
| return FALSE; |
| } |
| |
| len = recvfrom(client_sk, client->buf + client->buf_end, |
| TCP_MAX_BUF_LEN - client->buf_end, 0, |
| client_addr, client_addr_len); |
| if (len < 0) { |
| if (errno == EAGAIN || errno == EWOULDBLOCK) |
| return TRUE; |
| |
| debug("client %d cannot read errno %d/%s", client_sk, -errno, |
| strerror(errno)); |
| g_hash_table_remove(partial_tcp_req_table, |
| GINT_TO_POINTER(client_sk)); |
| return FALSE; |
| } |
| |
| return read_tcp_data(client, client_addr, *client_addr_len, len); |
| } |
| |
| static gboolean client_timeout(gpointer user_data) |
| { |
| struct tcp_partial_client_data *client = user_data; |
| int sock = g_io_channel_unix_get_fd(client->channel); |
| |
| debug("client %d timeout pending %d bytes", sock, client->buf_end); |
| |
| g_hash_table_remove(partial_tcp_req_table, GINT_TO_POINTER(sock)); |
| |
| return FALSE; |
| } |
| |
| static bool tcp_listener_event(GIOChannel *channel, GIOCondition condition, |
| struct listener_data *ifdata, int family, |
| guint *listener_watch) |
| { |
| int sk = -1, client_sk = -1; |
| int recv_len; |
| size_t msg_len; |
| fd_set readfds; |
| struct timeval tv = {.tv_sec = 0, .tv_usec = 0}; |
| |
| struct tcp_partial_client_data *client; |
| struct sockaddr_in6 client_addr6; |
| socklen_t client_addr6_len = sizeof(client_addr6); |
| struct sockaddr_in client_addr4; |
| socklen_t client_addr4_len = sizeof(client_addr4); |
| void *client_addr; |
| socklen_t *client_addr_len; |
| |
| debug("condition 0x%02x channel %p ifdata %p family %d", |
| condition, channel, ifdata, family); |
| |
| if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) { |
| if (*listener_watch > 0) |
| g_source_remove(*listener_watch); |
| *listener_watch = 0; |
| |
| connman_error("Error with TCP listener channel"); |
| |
| return false; |
| } |
| |
| sk = g_io_channel_unix_get_fd(channel); |
| |
| if (family == AF_INET) { |
| client_addr = &client_addr4; |
| client_addr_len = &client_addr4_len; |
| } else { |
| client_addr = &client_addr6; |
| client_addr_len = &client_addr6_len; |
| } |
| |
| FD_ZERO(&readfds); |
| FD_SET(sk, &readfds); |
| |
| /* TODO: check select return code */ |
| select(sk + 1, &readfds, NULL, NULL, &tv); |
| if (!FD_ISSET(sk, &readfds)) { |
| debug("No data to read from master %d, waiting.", sk); |
| return true; |
| } |
| |
| client_sk = accept(sk, client_addr, client_addr_len); |
| if (client_sk < 0) { |
| connman_error("Accept failure on TCP listener"); |
| *listener_watch = 0; |
| return false; |
| } |
| debug("client %d accepted", client_sk); |
| |
| fcntl(client_sk, F_SETFL, O_NONBLOCK); |
| |
| client = g_hash_table_lookup(partial_tcp_req_table, GINT_TO_POINTER(client_sk)); |
| if (!client) { |
| client = g_try_new0(struct tcp_partial_client_data, 1); |
| if (!client) { |
| close(client_sk); |
| return false; |
| } |
| |
| g_hash_table_insert(partial_tcp_req_table, |
| GINT_TO_POINTER(client_sk), |
| client); |
| |
| client->channel = g_io_channel_unix_new(client_sk); |
| g_io_channel_set_close_on_unref(client->channel, TRUE); |
| |
| client->watch = g_io_add_watch(client->channel, |
| G_IO_IN, tcp_client_event, |
| (gpointer)client); |
| |
| client->ifdata = ifdata; |
| |
| debug("client %d created %p", client_sk, client); |
| } else { |
| debug("client %d already exists %p", client_sk, client); |
| } |
| |
| if (!client->buf) { |
| client->buf = g_try_malloc(TCP_MAX_BUF_LEN); |
| if (!client->buf) |
| return false; |
| } |
| memset(client->buf, 0, TCP_MAX_BUF_LEN); |
| client->buf_end = 0; |
| client->family = family; |
| |
| if (client->timeout == 0) |
| client->timeout = g_timeout_add_seconds(2, client_timeout, |
| client); |
| |
| /* |
| * Check how much data there is. If all is there, then we can |
| * proceed normally, otherwise read the bits until everything |
| * is received or timeout occurs. |
| */ |
| recv_len = recv(client_sk, client->buf, TCP_MAX_BUF_LEN, 0); |
| if (recv_len < 0) { |
| if (errno == EAGAIN || errno == EWOULDBLOCK) { |
| debug("client %d no data to read, waiting", client_sk); |
| return true; |
| } |
| |
| debug("client %d cannot read errno %d/%s", client_sk, -errno, |
| strerror(errno)); |
| g_hash_table_remove(partial_tcp_req_table, |
| GINT_TO_POINTER(client_sk)); |
| return true; |
| } |
| |
| if (recv_len < DNS_HEADER_TCP_EXTRA_BYTES) { |
| debug("client %d not enough data to read, waiting", client_sk); |
| client->buf_end += recv_len; |
| return true; |
| } |
| |
| msg_len = get_msg_len(client->buf); |
| if (msg_len > TCP_MAX_BUF_LEN) { |
| debug("client %d invalid message length %zd ignoring packet", |
| client_sk, msg_len); |
| g_hash_table_remove(partial_tcp_req_table, |
| GINT_TO_POINTER(client_sk)); |
| return true; |
| } |
| |
| /* |
| * The packet length bytes do not contain the total message length, |
| * that is the reason to -2 below. |
| */ |
| if (msg_len != (size_t)(recv_len - DNS_HEADER_TCP_EXTRA_BYTES)) { |
| debug("client %d sent %d bytes but expecting %zd pending %zd", |
| client_sk, recv_len, msg_len + 2, msg_len + 2 - recv_len); |
| |
| client->buf_end += recv_len; |
| return true; |
| } |
| |
| return read_tcp_data(client, client_addr, *client_addr_len, recv_len); |
| } |
| |
| static gboolean tcp4_listener_event(GIOChannel *channel, GIOCondition condition, |
| gpointer user_data) |
| { |
| struct listener_data *ifdata = user_data; |
| |
| return tcp_listener_event(channel, condition, ifdata, AF_INET, |
| &ifdata->tcp4_listener_watch); |
| } |
| |
| static gboolean tcp6_listener_event(GIOChannel *channel, GIOCondition condition, |
| gpointer user_data) |
| { |
| struct listener_data *ifdata = user_data; |
| |
| return tcp_listener_event(channel, condition, user_data, AF_INET6, |
| &ifdata->tcp6_listener_watch); |
| } |
| |
| static bool udp_listener_event(GIOChannel *channel, GIOCondition condition, |
| struct listener_data *ifdata, int family, |
| guint *listener_watch) |
| { |
| unsigned char buf[768]; |
| char query[512]; |
| struct request_data *req = NULL; |
| struct domain_hdr *hdr = NULL; |
| int sk = -1, err, len; |
| |
| struct sockaddr_in6 client_addr6; |
| socklen_t client_addr6_len = sizeof(client_addr6); |
| struct sockaddr_in client_addr4; |
| socklen_t client_addr4_len = sizeof(client_addr4); |
| void *client_addr; |
| socklen_t *client_addr_len; |
| |
| if (condition & (G_IO_NVAL | G_IO_ERR | G_IO_HUP)) { |
| connman_error("Error with UDP listener channel"); |
| *listener_watch = 0; |
| return false; |
| } |
| |
| if (family == AF_INET) { |
| client_addr = &client_addr4; |
| client_addr_len = &client_addr4_len; |
| } else { |
| client_addr = &client_addr6; |
| client_addr_len = &client_addr6_len; |
| } |
| |
| memset(client_addr, 0, *client_addr_len); |
| sk = g_io_channel_unix_get_fd(channel); |
| len = recvfrom(sk, buf, sizeof(buf), 0, client_addr, client_addr_len); |
| if (len < 2) |
| return true; |
| |
| debug("Received %d bytes (id 0x%04x)", len, buf[0] | buf[1] << 8); |
| |
| err = parse_request(buf, len, query, sizeof(query)); |
| if (err < 0 || (g_slist_length(server_list) == 0)) { |
| send_response(sk, buf, len, client_addr, |
| *client_addr_len, IPPROTO_UDP); |
| return true; |
| } |
| |
| req = g_try_new0(struct request_data, 1); |
| if (!req) |
| return true; |
| |
| memcpy(&req->sa, client_addr, *client_addr_len); |
| req->sa_len = *client_addr_len; |
| req->client_sk = 0; |
| req->protocol = IPPROTO_UDP; |
| req->family = family; |
| |
| hdr = (void*)buf; |
| |
| req->srcid = hdr->id; |
| req->dstid = get_id(); |
| req->altid = get_id(); |
| req->request_len = len; |
| |
| hdr->id = req->dstid; |
| |
| req->numserv = 0; |
| req->ifdata = ifdata; |
| req->append_domain = false; |
| |
| if (resolv(req, buf, query)) { |
| /* a cached result was sent, so the request can be released */ |
| g_free(req); |
| return true; |
| } |
| |
| req->name = g_strdup(query); |
| req->request = g_malloc(len); |
| memcpy(req->request, buf, len); |
| req->timeout = g_timeout_add_seconds(5, request_timeout, req); |
| request_list = g_slist_append(request_list, req); |
| |
| return true; |
| } |
| |
| static gboolean udp4_listener_event(GIOChannel *channel, GIOCondition condition, |
| gpointer user_data) |
| { |
| struct listener_data *ifdata = user_data; |
| |
| return udp_listener_event(channel, condition, ifdata, AF_INET, |
| &ifdata->udp4_listener_watch); |
| } |
| |
| static gboolean udp6_listener_event(GIOChannel *channel, GIOCondition condition, |
| gpointer user_data) |
| { |
| struct listener_data *ifdata = user_data; |
| |
| return udp_listener_event(channel, condition, user_data, AF_INET6, |
| &ifdata->udp6_listener_watch); |
| } |
| |
| static GIOChannel *get_listener(int family, int protocol, int index) |
| { |
| GIOChannel *channel = NULL; |
| union { |
| struct sockaddr sa; |
| struct sockaddr_in6 sin6; |
| struct sockaddr_in sin; |
| } s; |
| socklen_t slen; |
| const char *proto = protocol_label(protocol); |
| const int type = socket_type(protocol, SOCK_CLOEXEC); |
| char *interface; |
| int sk = socket(family, type, protocol); |
| |
| debug("family %d protocol %d index %d", family, protocol, index); |
| |
| if (sk < 0) { |
| if (family == AF_INET6 && errno == EAFNOSUPPORT) { |
| connman_error("No IPv6 support"); |
| } else { |
| connman_error("Failed to create %s listener socket", proto); |
| } |
| return NULL; |
| } |
| |
| interface = connman_inet_ifname(index); |
| if (!interface || setsockopt(sk, SOL_SOCKET, SO_BINDTODEVICE, |
| interface, |
| strlen(interface) + 1) < 0) { |
| connman_error("Failed to bind %s listener interface " |
| "for %s (%d/%s)", |
| proto, family == AF_INET ? "IPv4" : "IPv6", |
| -errno, strerror(errno)); |
| close(sk); |
| g_free(interface); |
| return NULL; |
| } |
| g_free(interface); |
| |
| if (family == AF_INET6) { |
| memset(&s.sin6, 0, sizeof(s.sin6)); |
| s.sin6.sin6_family = AF_INET6; |
| s.sin6.sin6_port = htons(dns_listen_port); |
| slen = sizeof(s.sin6); |
| |
| if (__connman_inet_get_interface_address(index, |
| AF_INET6, |
| &s.sin6.sin6_addr) < 0) { |
| /* So we could not find suitable IPv6 address for |
| * the interface. This could happen if we have |
| * disabled IPv6 for the interface. |
| */ |
| close(sk); |
| return NULL; |
| } |
| |
| } else if (family == AF_INET) { |
| memset(&s.sin, 0, sizeof(s.sin)); |
| s.sin.sin_family = AF_INET; |
| s.sin.sin_port = htons(dns_listen_port); |
| slen = sizeof(s.sin); |
| |
| if (__connman_inet_get_interface_address(index, |
| AF_INET, |
| &s.sin.sin_addr) < 0) { |
| close(sk); |
| return NULL; |
| } |
| } else { |
| close(sk); |
| return NULL; |
| } |
| |
| if (bind(sk, &s.sa, slen) < 0) { |
| connman_error("Failed to bind %s listener socket", proto); |
| close(sk); |
| return NULL; |
| } |
| |
| if (protocol == IPPROTO_TCP) { |
| if (listen(sk, 10) < 0) { |
| connman_error("Failed to listen on TCP socket %d/%s", |
| -errno, strerror(errno)); |
| close(sk); |
| return NULL; |
| } |
| |
| fcntl(sk, F_SETFL, O_NONBLOCK); |
| } |
| |
| channel = g_io_channel_unix_new(sk); |
| if (!channel) { |
| connman_error("Failed to create %s listener channel", proto); |
| close(sk); |
| return NULL; |
| } |
| |
| g_io_channel_set_close_on_unref(channel, TRUE); |
| |
| return channel; |
| } |
| |
| #define UDP_IPv4_FAILED 0x01 |
| #define TCP_IPv4_FAILED 0x02 |
| #define UDP_IPv6_FAILED 0x04 |
| #define TCP_IPv6_FAILED 0x08 |
| #define UDP_FAILED (UDP_IPv4_FAILED | UDP_IPv6_FAILED) |
| #define TCP_FAILED (TCP_IPv4_FAILED | TCP_IPv6_FAILED) |
| #define IPv6_FAILED (UDP_IPv6_FAILED | TCP_IPv6_FAILED) |
| #define IPv4_FAILED (UDP_IPv4_FAILED | TCP_IPv4_FAILED) |
| |
| static int create_dns_listener(int protocol, struct listener_data *ifdata) |
| { |
| int ret = 0; |
| |
| if (protocol == IPPROTO_TCP) { |
| ifdata->tcp4_listener_channel = get_listener(AF_INET, protocol, |
| ifdata->index); |
| if (ifdata->tcp4_listener_channel) |
| ifdata->tcp4_listener_watch = |
| g_io_add_watch(ifdata->tcp4_listener_channel, |
| G_IO_IN, tcp4_listener_event, |
| (gpointer)ifdata); |
| else |
| ret |= TCP_IPv4_FAILED; |
| |
| ifdata->tcp6_listener_channel = get_listener(AF_INET6, protocol, |
| ifdata->index); |
| if (ifdata->tcp6_listener_channel) |
| ifdata->tcp6_listener_watch = |
| g_io_add_watch(ifdata->tcp6_listener_channel, |
| G_IO_IN, tcp6_listener_event, |
| (gpointer)ifdata); |
| else |
| ret |= TCP_IPv6_FAILED; |
| } else { |
| ifdata->udp4_listener_channel = get_listener(AF_INET, protocol, |
| ifdata->index); |
| if (ifdata->udp4_listener_channel) |
| ifdata->udp4_listener_watch = |
| g_io_add_watch(ifdata->udp4_listener_channel, |
| G_IO_IN, udp4_listener_event, |
| (gpointer)ifdata); |
| else |
| ret |= UDP_IPv4_FAILED; |
| |
| ifdata->udp6_listener_channel = get_listener(AF_INET6, protocol, |
| ifdata->index); |
| if (ifdata->udp6_listener_channel) |
| ifdata->udp6_listener_watch = |
| g_io_add_watch(ifdata->udp6_listener_channel, |
| G_IO_IN, udp6_listener_event, |
| (gpointer)ifdata); |
| else |
| ret |= UDP_IPv6_FAILED; |
| } |
| |
| return ret; |
| } |
| |
| static void destroy_udp_listener(struct listener_data *ifdata) |
| { |
| DBG("index %d", ifdata->index); |
| |
| if (ifdata->udp4_listener_watch > 0) |
| g_source_remove(ifdata->udp4_listener_watch); |
| |
| if (ifdata->udp6_listener_watch > 0) |
| g_source_remove(ifdata->udp6_listener_watch); |
| |
| if (ifdata->udp4_listener_channel) |
| g_io_channel_unref(ifdata->udp4_listener_channel); |
| if (ifdata->udp6_listener_channel) |
| g_io_channel_unref(ifdata->udp6_listener_channel); |
| } |
| |
| static void destroy_tcp_listener(struct listener_data *ifdata) |
| { |
| DBG("index %d", ifdata->index); |
| |
| if (ifdata->tcp4_listener_watch > 0) |
| g_source_remove(ifdata->tcp4_listener_watch); |
| if (ifdata->tcp6_listener_watch > 0) |
| g_source_remove(ifdata->tcp6_listener_watch); |
| |
| if (ifdata->tcp4_listener_channel) |
| g_io_channel_unref(ifdata->tcp4_listener_channel); |
| if (ifdata->tcp6_listener_channel) |
| g_io_channel_unref(ifdata->tcp6_listener_channel); |
| } |
| |
| static int create_listener(struct listener_data *ifdata) |
| { |
| int index, err; |
| |
| err = create_dns_listener(IPPROTO_UDP, ifdata); |
| if ((err & UDP_FAILED) == UDP_FAILED) |
| return -EIO; |
| |
| err |= create_dns_listener(IPPROTO_TCP, ifdata); |
| if ((err & TCP_FAILED) == TCP_FAILED) { |
| destroy_udp_listener(ifdata); |
| return -EIO; |
| } |
| |
| index = connman_inet_ifindex("lo"); |
| if (ifdata->index == index) { |
| if ((err & IPv6_FAILED) != IPv6_FAILED) |
| __connman_resolvfile_append(index, NULL, "::1"); |
| |
| if ((err & IPv4_FAILED) != IPv4_FAILED) |
| __connman_resolvfile_append(index, NULL, "127.0.0.1"); |
| } |
| |
| return 0; |
| } |
| |
| static void destroy_listener(struct listener_data *ifdata) |
| { |
| int index = connman_inet_ifindex("lo"); |
| |
| if (ifdata->index == index) { |
| __connman_resolvfile_remove(index, NULL, "127.0.0.1"); |
| __connman_resolvfile_remove(index, NULL, "::1"); |
| } |
| |
| for (GSList *list = request_list; list; list = list->next) { |
| struct request_data *req = list->data; |
| |
| debug("Dropping request (id 0x%04x -> 0x%04x)", |
| req->srcid, req->dstid); |
| destroy_request_data(req); |
| list->data = NULL; |
| } |
| |
| g_slist_free(request_list); |
| request_list = NULL; |
| |
| destroy_tcp_listener(ifdata); |
| destroy_udp_listener(ifdata); |
| } |
| |
| int __connman_dnsproxy_add_listener(int index) |
| { |
| struct listener_data *ifdata; |
| int err; |
| |
| DBG("index %d", index); |
| |
| if (index < 0) |
| return -EINVAL; |
| |
| if (!listener_table) |
| return -ENOENT; |
| |
| if (g_hash_table_lookup(listener_table, GINT_TO_POINTER(index))) |
| return 0; |
| |
| ifdata = g_try_new0(struct listener_data, 1); |
| if (!ifdata) |
| return -ENOMEM; |
| |
| ifdata->index = index; |
| ifdata->udp4_listener_channel = NULL; |
| ifdata->udp4_listener_watch = 0; |
| ifdata->tcp4_listener_channel = NULL; |
| ifdata->tcp4_listener_watch = 0; |
| ifdata->udp6_listener_channel = NULL; |
| ifdata->udp6_listener_watch = 0; |
| ifdata->tcp6_listener_channel = NULL; |
| ifdata->tcp6_listener_watch = 0; |
| |
| err = create_listener(ifdata); |
| if (err < 0) { |
| connman_error("Couldn't create listener for index %d err %d", |
| index, err); |
| g_free(ifdata); |
| return err; |
| } |
| g_hash_table_insert(listener_table, GINT_TO_POINTER(ifdata->index), |
| ifdata); |
| return 0; |
| } |
| |
| void __connman_dnsproxy_remove_listener(int index) |
| { |
| struct listener_data *ifdata; |
| DBG("index %d", index); |
| |
| if (!listener_table) |
| return; |
| |
| ifdata = g_hash_table_lookup(listener_table, GINT_TO_POINTER(index)); |
| if (!ifdata) |
| return; |
| |
| destroy_listener(ifdata); |
| |
| g_hash_table_remove(listener_table, GINT_TO_POINTER(index)); |
| } |
| |
| static void remove_listener(gpointer key, gpointer value, gpointer user_data) |
| { |
| int index = GPOINTER_TO_INT(key); |
| struct listener_data *ifdata = value; |
| |
| DBG("index %d", index); |
| |
| destroy_listener(ifdata); |
| } |
| |
| static void free_partial_reqs(gpointer value) |
| { |
| struct tcp_partial_client_data *data = value; |
| |
| client_reset(data); |
| g_free(data); |
| } |
| |
| int __connman_dnsproxy_init(void) |
| { |
| int err, index; |
| |
| DBG(""); |
| |
| listener_table = g_hash_table_new_full(g_direct_hash, g_direct_equal, |
| NULL, g_free); |
| |
| partial_tcp_req_table = g_hash_table_new_full(g_direct_hash, |
| g_direct_equal, |
| NULL, |
| free_partial_reqs); |
| |
| index = connman_inet_ifindex("lo"); |
| err = __connman_dnsproxy_add_listener(index); |
| if (err < 0) |
| return err; |
| |
| err = connman_notifier_register(&dnsproxy_notifier); |
| if (err < 0) { |
| __connman_dnsproxy_remove_listener(index); |
| g_hash_table_destroy(listener_table); |
| g_hash_table_destroy(partial_tcp_req_table); |
| |
| return err; |
| } |
| |
| return 0; |
| } |
| |
| int __connman_dnsproxy_set_mdns(int index, bool enabled) |
| { |
| return -ENOTSUP; |
| } |
| |
| void __connman_dnsproxy_cleanup(void) |
| { |
| DBG(""); |
| |
| if (cache_timer) { |
| g_source_remove(cache_timer); |
| cache_timer = 0; |
| } |
| |
| if (cache) { |
| g_hash_table_destroy(cache); |
| cache = NULL; |
| } |
| |
| connman_notifier_unregister(&dnsproxy_notifier); |
| |
| g_hash_table_foreach(listener_table, remove_listener, NULL); |
| |
| g_hash_table_destroy(listener_table); |
| |
| g_hash_table_destroy(partial_tcp_req_table); |
| |
| if (ipv4_resolve) |
| g_resolv_unref(ipv4_resolve); |
| if (ipv6_resolve) |
| g_resolv_unref(ipv6_resolve); |
| } |
| |
| void __connman_dnsproxy_set_listen_port(unsigned int port) |
| { |
| dns_listen_port = port; |
| } |