blob: 3fb0ed5e4789e066d07992e764fd76de5fe1e459 [file] [log] [blame]
/*
* INET An implementation of the TCP/IP protocol suite for the LINUX
* operating system. INET is implemented using the BSD Socket
* interface as the means of communication with the user level.
*
* The User Datagram Protocol (UDP).
*
* Authors: Ross Biro
* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
* Alan Cox, <alan@lxorguk.ukuu.org.uk>
* Hirokazu Takahashi, <taka@valinux.co.jp>
*
* Fixes:
* Alan Cox : verify_area() calls
* Alan Cox : stopped close while in use off icmp
* messages. Not a fix but a botch that
* for udp at least is 'valid'.
* Alan Cox : Fixed icmp handling properly
* Alan Cox : Correct error for oversized datagrams
* Alan Cox : Tidied select() semantics.
* Alan Cox : udp_err() fixed properly, also now
* select and read wake correctly on errors
* Alan Cox : udp_send verify_area moved to avoid mem leak
* Alan Cox : UDP can count its memory
* Alan Cox : send to an unknown connection causes
* an ECONNREFUSED off the icmp, but
* does NOT close.
* Alan Cox : Switched to new sk_buff handlers. No more backlog!
* Alan Cox : Using generic datagram code. Even smaller and the PEEK
* bug no longer crashes it.
* Fred Van Kempen : Net2e support for sk->broadcast.
* Alan Cox : Uses skb_free_datagram
* Alan Cox : Added get/set sockopt support.
* Alan Cox : Broadcasting without option set returns EACCES.
* Alan Cox : No wakeup calls. Instead we now use the callbacks.
* Alan Cox : Use ip_tos and ip_ttl
* Alan Cox : SNMP Mibs
* Alan Cox : MSG_DONTROUTE, and 0.0.0.0 support.
* Matt Dillon : UDP length checks.
* Alan Cox : Smarter af_inet used properly.
* Alan Cox : Use new kernel side addressing.
* Alan Cox : Incorrect return on truncated datagram receive.
* Arnt Gulbrandsen : New udp_send and stuff
* Alan Cox : Cache last socket
* Alan Cox : Route cache
* Jon Peatfield : Minor efficiency fix to sendto().
* Mike Shaver : RFC1122 checks.
* Alan Cox : Nonblocking error fix.
* Willy Konynenberg : Transparent proxying support.
* Mike McLagan : Routing by source
* David S. Miller : New socket lookup architecture.
* Last socket cache retained as it
* does have a high hit rate.
* Olaf Kirch : Don't linearise iovec on sendmsg.
* Andi Kleen : Some cleanups, cache destination entry
* for connect.
* Vitaly E. Lavrov : Transparent proxy revived after year coma.
* Melvin Smith : Check msg_name not msg_namelen in sendto(),
* return ENOTCONN for unconnected sockets (POSIX)
* Janos Farkas : don't deliver multi/broadcasts to a different
* bound-to-device socket
* Hirokazu Takahashi : HW checksumming for outgoing UDP
* datagrams.
* Hirokazu Takahashi : sendfile() on UDP works now.
* Arnaldo C. Melo : convert /proc/net/udp to seq_file
* YOSHIFUJI Hideaki @USAGI and: Support IPV6_V6ONLY socket option, which
* Alexey Kuznetsov: allow both IPv4 and IPv6 sockets to bind
* a single port at the same time.
* Derek Atkins <derek@ihtfp.com>: Add Encapulation Support
* James Chapman : Add L2TP encapsulation type.
*
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#define pr_fmt(fmt) "UDP: " fmt
#include <linux/uaccess.h>
#include <asm/ioctls.h>
#include <linux/memblock.h>
#include <linux/highmem.h>
#include <linux/swap.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/module.h>
#include <linux/socket.h>
#include <linux/sockios.h>
#include <linux/igmp.h>
#include <linux/inetdevice.h>
#include <linux/in.h>
#include <linux/errno.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/slab.h>
#include <net/tcp_states.h>
#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <net/net_namespace.h>
#include <net/icmp.h>
#include <net/inet_hashtables.h>
#include <net/ip_tunnels.h>
#include <net/route.h>
#include <net/checksum.h>
#include <net/xfrm.h>
#include <trace/events/udp.h>
#include <linux/static_key.h>
#include <trace/events/skb.h>
#include <net/busy_poll.h>
#include "udp_impl.h"
#include <net/sock_reuseport.h>
#include <net/addrconf.h>
#include <net/udp_tunnel.h>
struct udp_table udp_table __read_mostly;
EXPORT_SYMBOL(udp_table);
long sysctl_udp_mem[3] __read_mostly;
EXPORT_SYMBOL(sysctl_udp_mem);
atomic_long_t udp_memory_allocated;
EXPORT_SYMBOL(udp_memory_allocated);
#define MAX_UDP_PORTS 65536
#define PORTS_PER_CHAIN (MAX_UDP_PORTS / UDP_HTABLE_SIZE_MIN)
/* IPCB reference means this can not be used from early demux */
static bool udp_lib_exact_dif_match(struct net *net, struct sk_buff *skb)
{
#if IS_ENABLED(CONFIG_NET_L3_MASTER_DEV)
if (!net->ipv4.sysctl_udp_l3mdev_accept &&
skb && ipv4_l3mdev_skb(IPCB(skb)->flags))
return true;
#endif
return false;
}
static int udp_lib_lport_inuse(struct net *net, __u16 num,
const struct udp_hslot *hslot,
unsigned long *bitmap,
struct sock *sk, unsigned int log)
{
struct sock *sk2;
kuid_t uid = sock_i_uid(sk);
sk_for_each(sk2, &hslot->head) {
if (net_eq(sock_net(sk2), net) &&
sk2 != sk &&
(bitmap || udp_sk(sk2)->udp_port_hash == num) &&
(!sk2->sk_reuse || !sk->sk_reuse) &&
(!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
inet_rcv_saddr_equal(sk, sk2, true)) {
if (sk2->sk_reuseport && sk->sk_reuseport &&
!rcu_access_pointer(sk->sk_reuseport_cb) &&
uid_eq(uid, sock_i_uid(sk2))) {
if (!bitmap)
return 0;
} else {
if (!bitmap)
return 1;
__set_bit(udp_sk(sk2)->udp_port_hash >> log,
bitmap);
}
}
}
return 0;
}
/*
* Note: we still hold spinlock of primary hash chain, so no other writer
* can insert/delete a socket with local_port == num
*/
static int udp_lib_lport_inuse2(struct net *net, __u16 num,
struct udp_hslot *hslot2,
struct sock *sk)
{
struct sock *sk2;
kuid_t uid = sock_i_uid(sk);
int res = 0;
spin_lock(&hslot2->lock);
udp_portaddr_for_each_entry(sk2, &hslot2->head) {
if (net_eq(sock_net(sk2), net) &&
sk2 != sk &&
(udp_sk(sk2)->udp_port_hash == num) &&
(!sk2->sk_reuse || !sk->sk_reuse) &&
(!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if ||
sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
inet_rcv_saddr_equal(sk, sk2, true)) {
if (sk2->sk_reuseport && sk->sk_reuseport &&
!rcu_access_pointer(sk->sk_reuseport_cb) &&
uid_eq(uid, sock_i_uid(sk2))) {
res = 0;
} else {
res = 1;
}
break;
}
}
spin_unlock(&hslot2->lock);
return res;
}
static int udp_reuseport_add_sock(struct sock *sk, struct udp_hslot *hslot)
{
struct net *net = sock_net(sk);
kuid_t uid = sock_i_uid(sk);
struct sock *sk2;
sk_for_each(sk2, &hslot->head) {
if (net_eq(sock_net(sk2), net) &&
sk2 != sk &&
sk2->sk_family == sk->sk_family &&
ipv6_only_sock(sk2) == ipv6_only_sock(sk) &&
(udp_sk(sk2)->udp_port_hash == udp_sk(sk)->udp_port_hash) &&
(sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
sk2->sk_reuseport && uid_eq(uid, sock_i_uid(sk2)) &&
inet_rcv_saddr_equal(sk, sk2, false)) {
return reuseport_add_sock(sk, sk2,
inet_rcv_saddr_any(sk));
}
}
return reuseport_alloc(sk, inet_rcv_saddr_any(sk));
}
/**
* udp_lib_get_port - UDP/-Lite port lookup for IPv4 and IPv6
*
* @sk: socket struct in question
* @snum: port number to look up
* @hash2_nulladdr: AF-dependent hash value in secondary hash chains,
* with NULL address
*/
int udp_lib_get_port(struct sock *sk, unsigned short snum,
unsigned int hash2_nulladdr)
{
struct udp_hslot *hslot, *hslot2;
struct udp_table *udptable = sk->sk_prot->h.udp_table;
int error = 1;
struct net *net = sock_net(sk);
if (!snum) {
int low, high, remaining;
unsigned int rand;
unsigned short first, last;
DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN);
inet_get_local_port_range(net, &low, &high);
remaining = (high - low) + 1;
rand = prandom_u32();
first = reciprocal_scale(rand, remaining) + low;
/*
* force rand to be an odd multiple of UDP_HTABLE_SIZE
*/
rand = (rand | 1) * (udptable->mask + 1);
last = first + udptable->mask + 1;
do {
hslot = udp_hashslot(udptable, net, first);
bitmap_zero(bitmap, PORTS_PER_CHAIN);
spin_lock_bh(&hslot->lock);
udp_lib_lport_inuse(net, snum, hslot, bitmap, sk,
udptable->log);
snum = first;
/*
* Iterate on all possible values of snum for this hash.
* Using steps of an odd multiple of UDP_HTABLE_SIZE
* give us randomization and full range coverage.
*/
do {
if (low <= snum && snum <= high &&
!test_bit(snum >> udptable->log, bitmap) &&
!inet_is_local_reserved_port(net, snum))
goto found;
snum += rand;
} while (snum != first);
spin_unlock_bh(&hslot->lock);
cond_resched();
} while (++first != last);
goto fail;
} else {
hslot = udp_hashslot(udptable, net, snum);
spin_lock_bh(&hslot->lock);
if (hslot->count > 10) {
int exist;
unsigned int slot2 = udp_sk(sk)->udp_portaddr_hash ^ snum;
slot2 &= udptable->mask;
hash2_nulladdr &= udptable->mask;
hslot2 = udp_hashslot2(udptable, slot2);
if (hslot->count < hslot2->count)
goto scan_primary_hash;
exist = udp_lib_lport_inuse2(net, snum, hslot2, sk);
if (!exist && (hash2_nulladdr != slot2)) {
hslot2 = udp_hashslot2(udptable, hash2_nulladdr);
exist = udp_lib_lport_inuse2(net, snum, hslot2,
sk);
}
if (exist)
goto fail_unlock;
else
goto found;
}
scan_primary_hash:
if (udp_lib_lport_inuse(net, snum, hslot, NULL, sk, 0))
goto fail_unlock;
}
found:
inet_sk(sk)->inet_num = snum;
udp_sk(sk)->udp_port_hash = snum;
udp_sk(sk)->udp_portaddr_hash ^= snum;
if (sk_unhashed(sk)) {
if (sk->sk_reuseport &&
udp_reuseport_add_sock(sk, hslot)) {
inet_sk(sk)->inet_num = 0;
udp_sk(sk)->udp_port_hash = 0;
udp_sk(sk)->udp_portaddr_hash ^= snum;
goto fail_unlock;
}
sk_add_node_rcu(sk, &hslot->head);
hslot->count++;
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, 1);
hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
spin_lock(&hslot2->lock);
if (IS_ENABLED(CONFIG_IPV6) && sk->sk_reuseport &&
sk->sk_family == AF_INET6)
hlist_add_tail_rcu(&udp_sk(sk)->udp_portaddr_node,
&hslot2->head);
else
hlist_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
&hslot2->head);
hslot2->count++;
spin_unlock(&hslot2->lock);
}
sock_set_flag(sk, SOCK_RCU_FREE);
error = 0;
fail_unlock:
spin_unlock_bh(&hslot->lock);
fail:
return error;
}
EXPORT_SYMBOL(udp_lib_get_port);
int udp_v4_get_port(struct sock *sk, unsigned short snum)
{
unsigned int hash2_nulladdr =
ipv4_portaddr_hash(sock_net(sk), htonl(INADDR_ANY), snum);
unsigned int hash2_partial =
ipv4_portaddr_hash(sock_net(sk), inet_sk(sk)->inet_rcv_saddr, 0);
/* precompute partial secondary hash */
udp_sk(sk)->udp_portaddr_hash = hash2_partial;
return udp_lib_get_port(sk, snum, hash2_nulladdr);
}
static int compute_score(struct sock *sk, struct net *net,
__be32 saddr, __be16 sport,
__be32 daddr, unsigned short hnum,
int dif, int sdif, bool exact_dif)
{
int score;
struct inet_sock *inet;
bool dev_match;
if (!net_eq(sock_net(sk), net) ||
udp_sk(sk)->udp_port_hash != hnum ||
ipv6_only_sock(sk))
return -1;
if (sk->sk_rcv_saddr != daddr)
return -1;
score = (sk->sk_family == PF_INET) ? 2 : 1;
inet = inet_sk(sk);
if (inet->inet_daddr) {
if (inet->inet_daddr != saddr)
return -1;
score += 4;
}
if (inet->inet_dport) {
if (inet->inet_dport != sport)
return -1;
score += 4;
}
dev_match = udp_sk_bound_dev_eq(net, sk->sk_bound_dev_if,
dif, sdif);
if (!dev_match)
return -1;
score += 4;
if (sk->sk_incoming_cpu == raw_smp_processor_id())
score++;
return score;
}
static u32 udp_ehashfn(const struct net *net, const __be32 laddr,
const __u16 lport, const __be32 faddr,
const __be16 fport)
{
static u32 udp_ehash_secret __read_mostly;
net_get_random_once(&udp_ehash_secret, sizeof(udp_ehash_secret));
return __inet_ehashfn(laddr, lport, faddr, fport,
udp_ehash_secret + net_hash_mix(net));
}
/* called with rcu_read_lock() */
static struct sock *udp4_lib_lookup2(struct net *net,
__be32 saddr, __be16 sport,
__be32 daddr, unsigned int hnum,
int dif, int sdif, bool exact_dif,
struct udp_hslot *hslot2,
struct sk_buff *skb)
{
struct sock *sk, *result;
int score, badness;
u32 hash = 0;
result = NULL;
badness = 0;
udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
score = compute_score(sk, net, saddr, sport,
daddr, hnum, dif, sdif, exact_dif);
if (score > badness) {
if (sk->sk_reuseport) {
hash = udp_ehashfn(net, daddr, hnum,
saddr, sport);
result = reuseport_select_sock(sk, hash, skb,
sizeof(struct udphdr));
if (result)
return result;
}
badness = score;
result = sk;
}
}
return result;
}
/* UDP is nearly always wildcards out the wazoo, it makes no sense to try
* harder than this. -DaveM
*/
struct sock *__udp4_lib_lookup(struct net *net, __be32 saddr,
__be16 sport, __be32 daddr, __be16 dport, int dif,
int sdif, struct udp_table *udptable, struct sk_buff *skb)
{
struct sock *result;
unsigned short hnum = ntohs(dport);
unsigned int hash2, slot2;
struct udp_hslot *hslot2;
bool exact_dif = udp_lib_exact_dif_match(net, skb);
hash2 = ipv4_portaddr_hash(net, daddr, hnum);
slot2 = hash2 & udptable->mask;
hslot2 = &udptable->hash2[slot2];
result = udp4_lib_lookup2(net, saddr, sport,
daddr, hnum, dif, sdif,
exact_dif, hslot2, skb);
if (!result) {
hash2 = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum);
slot2 = hash2 & udptable->mask;
hslot2 = &udptable->hash2[slot2];
result = udp4_lib_lookup2(net, saddr, sport,
htonl(INADDR_ANY), hnum, dif, sdif,
exact_dif, hslot2, skb);
}
if (unlikely(IS_ERR(result)))
return NULL;
return result;
}
EXPORT_SYMBOL_GPL(__udp4_lib_lookup);
static inline struct sock *__udp4_lib_lookup_skb(struct sk_buff *skb,
__be16 sport, __be16 dport,
struct udp_table *udptable)
{
const struct iphdr *iph = ip_hdr(skb);
return __udp4_lib_lookup(dev_net(skb->dev), iph->saddr, sport,
iph->daddr, dport, inet_iif(skb),
inet_sdif(skb), udptable, skb);
}
struct sock *udp4_lib_lookup_skb(struct sk_buff *skb,
__be16 sport, __be16 dport)
{
return __udp4_lib_lookup_skb(skb, sport, dport, &udp_table);
}
EXPORT_SYMBOL_GPL(udp4_lib_lookup_skb);
/* Must be called under rcu_read_lock().
* Does increment socket refcount.
*/
#if IS_ENABLED(CONFIG_NF_TPROXY_IPV4) || IS_ENABLED(CONFIG_NF_SOCKET_IPV4)
struct sock *udp4_lib_lookup(struct net *net, __be32 saddr, __be16 sport,
__be32 daddr, __be16 dport, int dif)
{
struct sock *sk;
sk = __udp4_lib_lookup(net, saddr, sport, daddr, dport,
dif, 0, &udp_table, NULL);
if (sk && !refcount_inc_not_zero(&sk->sk_refcnt))
sk = NULL;
return sk;
}
EXPORT_SYMBOL_GPL(udp4_lib_lookup);
#endif
static inline bool __udp_is_mcast_sock(struct net *net, struct sock *sk,
__be16 loc_port, __be32 loc_addr,
__be16 rmt_port, __be32 rmt_addr,
int dif, int sdif, unsigned short hnum)
{
struct inet_sock *inet = inet_sk(sk);
if (!net_eq(sock_net(sk), net) ||
udp_sk(sk)->udp_port_hash != hnum ||
(inet->inet_daddr && inet->inet_daddr != rmt_addr) ||
(inet->inet_dport != rmt_port && inet->inet_dport) ||
(inet->inet_rcv_saddr && inet->inet_rcv_saddr != loc_addr) ||
ipv6_only_sock(sk) ||
(sk->sk_bound_dev_if && sk->sk_bound_dev_if != dif &&
sk->sk_bound_dev_if != sdif))
return false;
if (!ip_mc_sf_allow(sk, loc_addr, rmt_addr, dif, sdif))
return false;
return true;
}
DEFINE_STATIC_KEY_FALSE(udp_encap_needed_key);
void udp_encap_enable(void)
{
static_branch_inc(&udp_encap_needed_key);
}
EXPORT_SYMBOL(udp_encap_enable);
/* Handler for tunnels with arbitrary destination ports: no socket lookup, go
* through error handlers in encapsulations looking for a match.
*/
static int __udp4_lib_err_encap_no_sk(struct sk_buff *skb, u32 info)
{
int i;
for (i = 0; i < MAX_IPTUN_ENCAP_OPS; i++) {
int (*handler)(struct sk_buff *skb, u32 info);
if (!iptun_encaps[i])
continue;
handler = rcu_dereference(iptun_encaps[i]->err_handler);
if (handler && !handler(skb, info))
return 0;
}
return -ENOENT;
}
/* Try to match ICMP errors to UDP tunnels by looking up a socket without
* reversing source and destination port: this will match tunnels that force the
* same destination port on both endpoints (e.g. VXLAN, GENEVE). Note that
* lwtunnels might actually break this assumption by being configured with
* different destination ports on endpoints, in this case we won't be able to
* trace ICMP messages back to them.
*
* If this doesn't match any socket, probe tunnels with arbitrary destination
* ports (e.g. FoU, GUE): there, the receiving socket is useless, as the port
* we've sent packets to won't necessarily match the local destination port.
*
* Then ask the tunnel implementation to match the error against a valid
* association.
*
* Return an error if we can't find a match, the socket if we need further
* processing, zero otherwise.
*/
static struct sock *__udp4_lib_err_encap(struct net *net,
const struct iphdr *iph,
struct udphdr *uh,
struct udp_table *udptable,
struct sk_buff *skb, u32 info)
{
int network_offset, transport_offset;
struct sock *sk;
network_offset = skb_network_offset(skb);
transport_offset = skb_transport_offset(skb);
/* Network header needs to point to the outer IPv4 header inside ICMP */
skb_reset_network_header(skb);
/* Transport header needs to point to the UDP header */
skb_set_transport_header(skb, iph->ihl << 2);
sk = __udp4_lib_lookup(net, iph->daddr, uh->source,
iph->saddr, uh->dest, skb->dev->ifindex, 0,
udptable, NULL);
if (sk) {
int (*lookup)(struct sock *sk, struct sk_buff *skb);
struct udp_sock *up = udp_sk(sk);
lookup = READ_ONCE(up->encap_err_lookup);
if (!lookup || lookup(sk, skb))
sk = NULL;
}
if (!sk)
sk = ERR_PTR(__udp4_lib_err_encap_no_sk(skb, info));
skb_set_transport_header(skb, transport_offset);
skb_set_network_header(skb, network_offset);
return sk;
}
/*
* This routine is called by the ICMP module when it gets some
* sort of error condition. If err < 0 then the socket should
* be closed and the error returned to the user. If err > 0
* it's just the icmp type << 8 | icmp code.
* Header points to the ip header of the error packet. We move
* on past this. Then (as it used to claim before adjustment)
* header points to the first 8 bytes of the udp header. We need
* to find the appropriate port.
*/
int __udp4_lib_err(struct sk_buff *skb, u32 info, struct udp_table *udptable)
{
struct inet_sock *inet;
const struct iphdr *iph = (const struct iphdr *)skb->data;
struct udphdr *uh = (struct udphdr *)(skb->data+(iph->ihl<<2));
const int type = icmp_hdr(skb)->type;
const int code = icmp_hdr(skb)->code;
bool tunnel = false;
struct sock *sk;
int harderr;
int err;
struct net *net = dev_net(skb->dev);
sk = __udp4_lib_lookup(net, iph->daddr, uh->dest,
iph->saddr, uh->source, skb->dev->ifindex,
inet_sdif(skb), udptable, NULL);
if (!sk) {
/* No socket for error: try tunnels before discarding */
sk = ERR_PTR(-ENOENT);
if (static_branch_unlikely(&udp_encap_needed_key)) {
sk = __udp4_lib_err_encap(net, iph, uh, udptable, skb,
info);
if (!sk)
return 0;
}
if (IS_ERR(sk)) {
__ICMP_INC_STATS(net, ICMP_MIB_INERRORS);
return PTR_ERR(sk);
}
tunnel = true;
}
err = 0;
harderr = 0;
inet = inet_sk(sk);
switch (type) {
default:
case ICMP_TIME_EXCEEDED:
err = EHOSTUNREACH;
break;
case ICMP_SOURCE_QUENCH:
goto out;
case ICMP_PARAMETERPROB:
err = EPROTO;
harderr = 1;
break;
case ICMP_DEST_UNREACH:
if (code == ICMP_FRAG_NEEDED) { /* Path MTU discovery */
ipv4_sk_update_pmtu(skb, sk, info);
if (inet->pmtudisc != IP_PMTUDISC_DONT) {
err = EMSGSIZE;
harderr = 1;
break;
}
goto out;
}
err = EHOSTUNREACH;
if (code <= NR_ICMP_UNREACH) {
harderr = icmp_err_convert[code].fatal;
err = icmp_err_convert[code].errno;
}
break;
case ICMP_REDIRECT:
ipv4_sk_redirect(skb, sk);
goto out;
}
/*
* RFC1122: OK. Passes ICMP errors back to application, as per
* 4.1.3.3.
*/
if (tunnel) {
/* ...not for tunnels though: we don't have a sending socket */
goto out;
}
if (!inet->recverr) {
if (!harderr || sk->sk_state != TCP_ESTABLISHED)
goto out;
} else
ip_icmp_error(sk, skb, err, uh->dest, info, (u8 *)(uh+1));
sk->sk_err = err;
sk->sk_error_report(sk);
out:
return 0;
}
int udp_err(struct sk_buff *skb, u32 info)
{
return __udp4_lib_err(skb, info, &udp_table);
}
/*
* Throw away all pending data and cancel the corking. Socket is locked.
*/
void udp_flush_pending_frames(struct sock *sk)
{
struct udp_sock *up = udp_sk(sk);
if (up->pending) {
up->len = 0;
up->pending = 0;
ip_flush_pending_frames(sk);
}
}
EXPORT_SYMBOL(udp_flush_pending_frames);
/**
* udp4_hwcsum - handle outgoing HW checksumming
* @skb: sk_buff containing the filled-in UDP header
* (checksum field must be zeroed out)
* @src: source IP address
* @dst: destination IP address
*/
void udp4_hwcsum(struct sk_buff *skb, __be32 src, __be32 dst)
{
struct udphdr *uh = udp_hdr(skb);
int offset = skb_transport_offset(skb);
int len = skb->len - offset;
int hlen = len;
__wsum csum = 0;
if (!skb_has_frag_list(skb)) {
/*
* Only one fragment on the socket.
*/
skb->csum_start = skb_transport_header(skb) - skb->head;
skb->csum_offset = offsetof(struct udphdr, check);
uh->check = ~csum_tcpudp_magic(src, dst, len,
IPPROTO_UDP, 0);
} else {
struct sk_buff *frags;
/*
* HW-checksum won't work as there are two or more
* fragments on the socket so that all csums of sk_buffs
* should be together
*/
skb_walk_frags(skb, frags) {
csum = csum_add(csum, frags->csum);
hlen -= frags->len;
}
csum = skb_checksum(skb, offset, hlen, csum);
skb->ip_summed = CHECKSUM_NONE;
uh->check = csum_tcpudp_magic(src, dst, len, IPPROTO_UDP, csum);
if (uh->check == 0)
uh->check = CSUM_MANGLED_0;
}
}
EXPORT_SYMBOL_GPL(udp4_hwcsum);
/* Function to set UDP checksum for an IPv4 UDP packet. This is intended
* for the simple case like when setting the checksum for a UDP tunnel.
*/
void udp_set_csum(bool nocheck, struct sk_buff *skb,
__be32 saddr, __be32 daddr, int len)
{
struct udphdr *uh = udp_hdr(skb);
if (nocheck) {
uh->check = 0;
} else if (skb_is_gso(skb)) {
uh->check = ~udp_v4_check(len, saddr, daddr, 0);
} else if (skb->ip_summed == CHECKSUM_PARTIAL) {
uh->check = 0;
uh->check = udp_v4_check(len, saddr, daddr, lco_csum(skb));
if (uh->check == 0)
uh->check = CSUM_MANGLED_0;
} else {
skb->ip_summed = CHECKSUM_PARTIAL;
skb->csum_start = skb_transport_header(skb) - skb->head;
skb->csum_offset = offsetof(struct udphdr, check);
uh->check = ~udp_v4_check(len, saddr, daddr, 0);
}
}
EXPORT_SYMBOL(udp_set_csum);
static int udp_send_skb(struct sk_buff *skb, struct flowi4 *fl4,
struct inet_cork *cork)
{
struct sock *sk = skb->sk;
struct inet_sock *inet = inet_sk(sk);
struct udphdr *uh;
int err = 0;
int is_udplite = IS_UDPLITE(sk);
int offset = skb_transport_offset(skb);
int len = skb->len - offset;
__wsum csum = 0;
/*
* Create a UDP header
*/
uh = udp_hdr(skb);
uh->source = inet->inet_sport;
uh->dest = fl4->fl4_dport;
uh->len = htons(len);
uh->check = 0;
if (cork->gso_size) {
const int hlen = skb_network_header_len(skb) +
sizeof(struct udphdr);
if (hlen + cork->gso_size > cork->fragsize)
return -EINVAL;
if (skb->len > cork->gso_size * UDP_MAX_SEGMENTS)
return -EINVAL;
if (sk->sk_no_check_tx)
return -EINVAL;
if (skb->ip_summed != CHECKSUM_PARTIAL || is_udplite ||
dst_xfrm(skb_dst(skb)))
return -EIO;
skb_shinfo(skb)->gso_size = cork->gso_size;
skb_shinfo(skb)->gso_type = SKB_GSO_UDP_L4;
skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(len - sizeof(uh),
cork->gso_size);
goto csum_partial;
}
if (is_udplite) /* UDP-Lite */
csum = udplite_csum(skb);
else if (sk->sk_no_check_tx) { /* UDP csum off */
skb->ip_summed = CHECKSUM_NONE;
goto send;
} else if (skb->ip_summed == CHECKSUM_PARTIAL) { /* UDP hardware csum */
csum_partial:
udp4_hwcsum(skb, fl4->saddr, fl4->daddr);
goto send;
} else
csum = udp_csum(skb);
/* add protocol-dependent pseudo-header */
uh->check = csum_tcpudp_magic(fl4->saddr, fl4->daddr, len,
sk->sk_protocol, csum);
if (uh->check == 0)
uh->check = CSUM_MANGLED_0;
send:
err = ip_send_skb(sock_net(sk), skb);
if (err) {
if (err == -ENOBUFS && !inet->recverr) {
UDP_INC_STATS(sock_net(sk),
UDP_MIB_SNDBUFERRORS, is_udplite);
err = 0;
}
} else
UDP_INC_STATS(sock_net(sk),
UDP_MIB_OUTDATAGRAMS, is_udplite);
return err;
}
/*
* Push out all pending data as one UDP datagram. Socket is locked.
*/
int udp_push_pending_frames(struct sock *sk)
{
struct udp_sock *up = udp_sk(sk);
struct inet_sock *inet = inet_sk(sk);
struct flowi4 *fl4 = &inet->cork.fl.u.ip4;
struct sk_buff *skb;
int err = 0;
skb = ip_finish_skb(sk, fl4);
if (!skb)
goto out;
err = udp_send_skb(skb, fl4, &inet->cork.base);
out:
up->len = 0;
up->pending = 0;
return err;
}
EXPORT_SYMBOL(udp_push_pending_frames);
static int __udp_cmsg_send(struct cmsghdr *cmsg, u16 *gso_size)
{
switch (cmsg->cmsg_type) {
case UDP_SEGMENT:
if (cmsg->cmsg_len != CMSG_LEN(sizeof(__u16)))
return -EINVAL;
*gso_size = *(__u16 *)CMSG_DATA(cmsg);
return 0;
default:
return -EINVAL;
}
}
int udp_cmsg_send(struct sock *sk, struct msghdr *msg, u16 *gso_size)
{
struct cmsghdr *cmsg;
bool need_ip = false;
int err;
for_each_cmsghdr(cmsg, msg) {
if (!CMSG_OK(msg, cmsg))
return -EINVAL;
if (cmsg->cmsg_level != SOL_UDP) {
need_ip = true;
continue;
}
err = __udp_cmsg_send(cmsg, gso_size);
if (err)
return err;
}
return need_ip;
}
EXPORT_SYMBOL_GPL(udp_cmsg_send);
int udp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len)
{
struct inet_sock *inet = inet_sk(sk);
struct udp_sock *up = udp_sk(sk);
DECLARE_SOCKADDR(struct sockaddr_in *, usin, msg->msg_name);
struct flowi4 fl4_stack;
struct flowi4 *fl4;
int ulen = len;
struct ipcm_cookie ipc;
struct rtable *rt = NULL;
int free = 0;
int connected = 0;
__be32 daddr, faddr, saddr;
__be16 dport;
u8 tos;
int err, is_udplite = IS_UDPLITE(sk);
int corkreq = up->corkflag || msg->msg_flags&MSG_MORE;
int (*getfrag)(void *, char *, int, int, int, struct sk_buff *);
struct sk_buff *skb;
struct ip_options_data opt_copy;
if (len > 0xFFFF)
return -EMSGSIZE;
/*
* Check the flags.
*/
if (msg->msg_flags & MSG_OOB) /* Mirror BSD error message compatibility */
return -EOPNOTSUPP;
getfrag = is_udplite ? udplite_getfrag : ip_generic_getfrag;
fl4 = &inet->cork.fl.u.ip4;
if (up->pending) {
/*
* There are pending frames.
* The socket lock must be held while it's corked.
*/
lock_sock(sk);
if (likely(up->pending)) {
if (unlikely(up->pending != AF_INET)) {
release_sock(sk);
return -EINVAL;
}
goto do_append_data;
}
release_sock(sk);
}
ulen += sizeof(struct udphdr);
/*
* Get and verify the address.
*/
if (usin) {
if (msg->msg_namelen < sizeof(*usin))
return -EINVAL;
if (usin->sin_family != AF_INET) {
if (usin->sin_family != AF_UNSPEC)
return -EAFNOSUPPORT;
}
daddr = usin->sin_addr.s_addr;
dport = usin->sin_port;
if (dport == 0)
return -EINVAL;
} else {
if (sk->sk_state != TCP_ESTABLISHED)
return -EDESTADDRREQ;
daddr = inet->inet_daddr;
dport = inet->inet_dport;
/* Open fast path for connected socket.
Route will not be used, if at least one option is set.
*/
connected = 1;
}
ipcm_init_sk(&ipc, inet);
ipc.gso_size = up->gso_size;
if (msg->msg_controllen) {
err = udp_cmsg_send(sk, msg, &ipc.gso_size);
if (err > 0)
err = ip_cmsg_send(sk, msg, &ipc,
sk->sk_family == AF_INET6);
if (unlikely(err < 0)) {
kfree(ipc.opt);
return err;
}
if (ipc.opt)
free = 1;
connected = 0;
}
if (!ipc.opt) {
struct ip_options_rcu *inet_opt;
rcu_read_lock();
inet_opt = rcu_dereference(inet->inet_opt);
if (inet_opt) {
memcpy(&opt_copy, inet_opt,
sizeof(*inet_opt) + inet_opt->opt.optlen);
ipc.opt = &opt_copy.opt;
}
rcu_read_unlock();
}
if (cgroup_bpf_enabled && !connected) {
err = BPF_CGROUP_RUN_PROG_UDP4_SENDMSG_LOCK(sk,
(struct sockaddr *)usin, &ipc.addr);
if (err)
goto out_free;
if (usin) {
if (usin->sin_port == 0) {
/* BPF program set invalid port. Reject it. */
err = -EINVAL;
goto out_free;
}
daddr = usin->sin_addr.s_addr;
dport = usin->sin_port;
}
}
saddr = ipc.addr;
ipc.addr = faddr = daddr;
if (ipc.opt && ipc.opt->opt.srr) {
if (!daddr) {
err = -EINVAL;
goto out_free;
}
faddr = ipc.opt->opt.faddr;
connected = 0;
}
tos = get_rttos(&ipc, inet);
if (sock_flag(sk, SOCK_LOCALROUTE) ||
(msg->msg_flags & MSG_DONTROUTE) ||
(ipc.opt && ipc.opt->opt.is_strictroute)) {
tos |= RTO_ONLINK;
connected = 0;
}
if (ipv4_is_multicast(daddr)) {
if (!ipc.oif || netif_index_is_l3_master(sock_net(sk), ipc.oif))
ipc.oif = inet->mc_index;
if (!saddr)
saddr = inet->mc_addr;
connected = 0;
} else if (!ipc.oif) {
ipc.oif = inet->uc_index;
} else if (ipv4_is_lbcast(daddr) && inet->uc_index) {
/* oif is set, packet is to local broadcast and
* and uc_index is set. oif is most likely set
* by sk_bound_dev_if. If uc_index != oif check if the
* oif is an L3 master and uc_index is an L3 slave.
* If so, we want to allow the send using the uc_index.
*/
if (ipc.oif != inet->uc_index &&
ipc.oif == l3mdev_master_ifindex_by_index(sock_net(sk),
inet->uc_index)) {
ipc.oif = inet->uc_index;
}
}
if (connected)
rt = (struct rtable *)sk_dst_check(sk, 0);
if (!rt) {
struct net *net = sock_net(sk);
__u8 flow_flags = inet_sk_flowi_flags(sk);
fl4 = &fl4_stack;
flowi4_init_output(fl4, ipc.oif, sk->sk_mark, tos,
RT_SCOPE_UNIVERSE, sk->sk_protocol,
flow_flags,
faddr, saddr, dport, inet->inet_sport,
sk->sk_uid);
security_sk_classify_flow(sk, flowi4_to_flowi(fl4));
rt = ip_route_output_flow(net, fl4, sk);
if (IS_ERR(rt)) {
err = PTR_ERR(rt);
rt = NULL;
if (err == -ENETUNREACH)
IP_INC_STATS(net, IPSTATS_MIB_OUTNOROUTES);
goto out;
}
err = -EACCES;
if ((rt->rt_flags & RTCF_BROADCAST) &&
!sock_flag(sk, SOCK_BROADCAST))
goto out;
if (connected)
sk_dst_set(sk, dst_clone(&rt->dst));
}
if (msg->msg_flags&MSG_CONFIRM)
goto do_confirm;
back_from_confirm:
saddr = fl4->saddr;
if (!ipc.addr)
daddr = ipc.addr = fl4->daddr;
/* Lockless fast path for the non-corking case. */
if (!corkreq) {
struct inet_cork cork;
skb = ip_make_skb(sk, fl4, getfrag, msg, ulen,
sizeof(struct udphdr), &ipc, &rt,
&cork, msg->msg_flags);
err = PTR_ERR(skb);
if (!IS_ERR_OR_NULL(skb))
err = udp_send_skb(skb, fl4, &cork);
goto out;
}
lock_sock(sk);
if (unlikely(up->pending)) {
/* The socket is already corked while preparing it. */
/* ... which is an evident application bug. --ANK */
release_sock(sk);
net_dbg_ratelimited("socket already corked\n");
err = -EINVAL;
goto out;
}
/*
* Now cork the socket to pend data.
*/
fl4 = &inet->cork.fl.u.ip4;
fl4->daddr = daddr;
fl4->saddr = saddr;
fl4->fl4_dport = dport;
fl4->fl4_sport = inet->inet_sport;
up->pending = AF_INET;
do_append_data:
up->len += ulen;
err = ip_append_data(sk, fl4, getfrag, msg, ulen,
sizeof(struct udphdr), &ipc, &rt,
corkreq ? msg->msg_flags|MSG_MORE : msg->msg_flags);
if (err)
udp_flush_pending_frames(sk);
else if (!corkreq)
err = udp_push_pending_frames(sk);
else if (unlikely(skb_queue_empty(&sk->sk_write_queue)))
up->pending = 0;
release_sock(sk);
out:
ip_rt_put(rt);
out_free:
if (free)
kfree(ipc.opt);
if (!err)
return len;
/*
* ENOBUFS = no kernel mem, SOCK_NOSPACE = no sndbuf space. Reporting
* ENOBUFS might not be good (it's not tunable per se), but otherwise
* we don't have a good statistic (IpOutDiscards but it can be too many
* things). We could add another new stat but at least for now that
* seems like overkill.
*/
if (err == -ENOBUFS || test_bit(SOCK_NOSPACE, &sk->sk_socket->flags)) {
UDP_INC_STATS(sock_net(sk),
UDP_MIB_SNDBUFERRORS, is_udplite);
}
return err;
do_confirm:
if (msg->msg_flags & MSG_PROBE)
dst_confirm_neigh(&rt->dst, &fl4->daddr);
if (!(msg->msg_flags&MSG_PROBE) || len)
goto back_from_confirm;
err = 0;
goto out;
}
EXPORT_SYMBOL(udp_sendmsg);
int udp_sendpage(struct sock *sk, struct page *page, int offset,
size_t size, int flags)
{
struct inet_sock *inet = inet_sk(sk);
struct udp_sock *up = udp_sk(sk);
int ret;
if (flags & MSG_SENDPAGE_NOTLAST)
flags |= MSG_MORE;
if (!up->pending) {
struct msghdr msg = { .msg_flags = flags|MSG_MORE };
/* Call udp_sendmsg to specify destination address which
* sendpage interface can't pass.
* This will succeed only when the socket is connected.
*/
ret = udp_sendmsg(sk, &msg, 0);
if (ret < 0)
return ret;
}
lock_sock(sk);
if (unlikely(!up->pending)) {
release_sock(sk);
net_dbg_ratelimited("cork failed\n");
return -EINVAL;
}
ret = ip_append_page(sk, &inet->cork.fl.u.ip4,
page, offset, size, flags);
if (ret == -EOPNOTSUPP) {
release_sock(sk);
return sock_no_sendpage(sk->sk_socket, page, offset,
size, flags);
}
if (ret < 0) {
udp_flush_pending_frames(sk);
goto out;
}
up->len += size;
if (!(up->corkflag || (flags&MSG_MORE)))
ret = udp_push_pending_frames(sk);
if (!ret)
ret = size;
out:
release_sock(sk);
return ret;
}
#define UDP_SKB_IS_STATELESS 0x80000000
static void udp_set_dev_scratch(struct sk_buff *skb)
{
struct udp_dev_scratch *scratch = udp_skb_scratch(skb);
BUILD_BUG_ON(sizeof(struct udp_dev_scratch) > sizeof(long));
scratch->_tsize_state = skb->truesize;
#if BITS_PER_LONG == 64
scratch->len = skb->len;
scratch->csum_unnecessary = !!skb_csum_unnecessary(skb);
scratch->is_linear = !skb_is_nonlinear(skb);
#endif
/* all head states execept sp (dst, sk, nf) are always cleared by
* udp_rcv() and we need to preserve secpath, if present, to eventually
* process IP_CMSG_PASSSEC at recvmsg() time
*/
if (likely(!skb_sec_path(skb)))
scratch->_tsize_state |= UDP_SKB_IS_STATELESS;
}
static int udp_skb_truesize(struct sk_buff *skb)
{
return udp_skb_scratch(skb)->_tsize_state & ~UDP_SKB_IS_STATELESS;
}
static bool udp_skb_has_head_state(struct sk_buff *skb)
{
return !(udp_skb_scratch(skb)->_tsize_state & UDP_SKB_IS_STATELESS);
}
/* fully reclaim rmem/fwd memory allocated for skb */
static void udp_rmem_release(struct sock *sk, int size, int partial,
bool rx_queue_lock_held)
{
struct udp_sock *up = udp_sk(sk);
struct sk_buff_head *sk_queue;
int amt;
if (likely(partial)) {
up->forward_deficit += size;
size = up->forward_deficit;
if (size < (sk->sk_rcvbuf >> 2))
return;
} else {
size += up->forward_deficit;
}
up->forward_deficit = 0;
/* acquire the sk_receive_queue for fwd allocated memory scheduling,
* if the called don't held it already
*/
sk_queue = &sk->sk_receive_queue;
if (!rx_queue_lock_held)
spin_lock(&sk_queue->lock);
sk->sk_forward_alloc += size;
amt = (sk->sk_forward_alloc - partial) & ~(SK_MEM_QUANTUM - 1);
sk->sk_forward_alloc -= amt;
if (amt)
__sk_mem_reduce_allocated(sk, amt >> SK_MEM_QUANTUM_SHIFT);
atomic_sub(size, &sk->sk_rmem_alloc);
/* this can save us from acquiring the rx queue lock on next receive */
skb_queue_splice_tail_init(sk_queue, &up->reader_queue);
if (!rx_queue_lock_held)
spin_unlock(&sk_queue->lock);
}
/* Note: called with reader_queue.lock held.
* Instead of using skb->truesize here, find a copy of it in skb->dev_scratch
* This avoids a cache line miss while receive_queue lock is held.
* Look at __udp_enqueue_schedule_skb() to find where this copy is done.
*/
void udp_skb_destructor(struct sock *sk, struct sk_buff *skb)
{
prefetch(&skb->data);
udp_rmem_release(sk, udp_skb_truesize(skb), 1, false);
}
EXPORT_SYMBOL(udp_skb_destructor);
/* as above, but the caller held the rx queue lock, too */
static void udp_skb_dtor_locked(struct sock *sk, struct sk_buff *skb)
{
prefetch(&skb->data);
udp_rmem_release(sk, udp_skb_truesize(skb), 1, true);
}
/* Idea of busylocks is to let producers grab an extra spinlock
* to relieve pressure on the receive_queue spinlock shared by consumer.
* Under flood, this means that only one producer can be in line
* trying to acquire the receive_queue spinlock.
* These busylock can be allocated on a per cpu manner, instead of a
* per socket one (that would consume a cache line per socket)
*/
static int udp_busylocks_log __read_mostly;
static spinlock_t *udp_busylocks __read_mostly;
static spinlock_t *busylock_acquire(void *ptr)
{
spinlock_t *busy;
busy = udp_busylocks + hash_ptr(ptr, udp_busylocks_log);
spin_lock(busy);
return busy;
}
static void busylock_release(spinlock_t *busy)
{
if (busy)
spin_unlock(busy);
}
int __udp_enqueue_schedule_skb(struct sock *sk, struct sk_buff *skb)
{
struct sk_buff_head *list = &sk->sk_receive_queue;
int rmem, delta, amt, err = -ENOMEM;
spinlock_t *busy = NULL;
int size;
/* try to avoid the costly atomic add/sub pair when the receive
* queue is full; always allow at least a packet
*/
rmem = atomic_read(&sk->sk_rmem_alloc);
if (rmem > sk->sk_rcvbuf)
goto drop;
/* Under mem pressure, it might be helpful to help udp_recvmsg()
* having linear skbs :
* - Reduce memory overhead and thus increase receive queue capacity
* - Less cache line misses at copyout() time
* - Less work at consume_skb() (less alien page frag freeing)
*/
if (rmem > (sk->sk_rcvbuf >> 1)) {
skb_condense(skb);
busy = busylock_acquire(sk);
}
size = skb->truesize;
udp_set_dev_scratch(skb);
/* we drop only if the receive buf is full and the receive
* queue contains some other skb
*/
rmem = atomic_add_return(size, &sk->sk_rmem_alloc);
if (rmem > (size + sk->sk_rcvbuf))
goto uncharge_drop;
spin_lock(&list->lock);
if (size >= sk->sk_forward_alloc) {
amt = sk_mem_pages(size);
delta = amt << SK_MEM_QUANTUM_SHIFT;
if (!__sk_mem_raise_allocated(sk, delta, amt, SK_MEM_RECV)) {
err = -ENOBUFS;
spin_unlock(&list->lock);
goto uncharge_drop;
}
sk->sk_forward_alloc += delta;
}
sk->sk_forward_alloc -= size;
/* no need to setup a destructor, we will explicitly release the
* forward allocated memory on dequeue
*/
sock_skb_set_dropcount(sk, skb);
__skb_queue_tail(list, skb);
spin_unlock(&list->lock);
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_data_ready(sk);
busylock_release(busy);
return 0;
uncharge_drop:
atomic_sub(skb->truesize, &sk->sk_rmem_alloc);
drop:
atomic_inc(&sk->sk_drops);
busylock_release(busy);
return err;
}
EXPORT_SYMBOL_GPL(__udp_enqueue_schedule_skb);
void udp_destruct_sock(struct sock *sk)
{
/* reclaim completely the forward allocated memory */
struct udp_sock *up = udp_sk(sk);
unsigned int total = 0;
struct sk_buff *skb;
skb_queue_splice_tail_init(&sk->sk_receive_queue, &up->reader_queue);
while ((skb = __skb_dequeue(&up->reader_queue)) != NULL) {
total += skb->truesize;
kfree_skb(skb);
}
udp_rmem_release(sk, total, 0, true);
inet_sock_destruct(sk);
}
EXPORT_SYMBOL_GPL(udp_destruct_sock);
int udp_init_sock(struct sock *sk)
{
skb_queue_head_init(&udp_sk(sk)->reader_queue);
sk->sk_destruct = udp_destruct_sock;
return 0;
}
EXPORT_SYMBOL_GPL(udp_init_sock);
void skb_consume_udp(struct sock *sk, struct sk_buff *skb, int len)
{
if (unlikely(READ_ONCE(sk->sk_peek_off) >= 0)) {
bool slow = lock_sock_fast(sk);
sk_peek_offset_bwd(sk, len);
unlock_sock_fast(sk, slow);
}
if (!skb_unref(skb))
return;
/* In the more common cases we cleared the head states previously,
* see __udp_queue_rcv_skb().
*/
if (unlikely(udp_skb_has_head_state(skb)))
skb_release_head_state(skb);
__consume_stateless_skb(skb);
}
EXPORT_SYMBOL_GPL(skb_consume_udp);
static struct sk_buff *__first_packet_length(struct sock *sk,
struct sk_buff_head *rcvq,
int *total)
{
struct sk_buff *skb;
while ((skb = skb_peek(rcvq)) != NULL) {
if (udp_lib_checksum_complete(skb)) {
__UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS,
IS_UDPLITE(sk));
__UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS,
IS_UDPLITE(sk));
atomic_inc(&sk->sk_drops);
__skb_unlink(skb, rcvq);
*total += skb->truesize;
kfree_skb(skb);
} else {
/* the csum related bits could be changed, refresh
* the scratch area
*/
udp_set_dev_scratch(skb);
break;
}
}
return skb;
}
/**
* first_packet_length - return length of first packet in receive queue
* @sk: socket
*
* Drops all bad checksum frames, until a valid one is found.
* Returns the length of found skb, or -1 if none is found.
*/
static int first_packet_length(struct sock *sk)
{
struct sk_buff_head *rcvq = &udp_sk(sk)->reader_queue;
struct sk_buff_head *sk_queue = &sk->sk_receive_queue;
struct sk_buff *skb;
int total = 0;
int res;
spin_lock_bh(&rcvq->lock);
skb = __first_packet_length(sk, rcvq, &total);
if (!skb && !skb_queue_empty(sk_queue)) {
spin_lock(&sk_queue->lock);
skb_queue_splice_tail_init(sk_queue, rcvq);
spin_unlock(&sk_queue->lock);
skb = __first_packet_length(sk, rcvq, &total);
}
res = skb ? skb->len : -1;
if (total)
udp_rmem_release(sk, total, 1, false);
spin_unlock_bh(&rcvq->lock);
return res;
}
/*
* IOCTL requests applicable to the UDP protocol
*/
int udp_ioctl(struct sock *sk, int cmd, unsigned long arg)
{
switch (cmd) {
case SIOCOUTQ:
{
int amount = sk_wmem_alloc_get(sk);
return put_user(amount, (int __user *)arg);
}
case SIOCINQ:
{
int amount = max_t(int, 0, first_packet_length(sk));
return put_user(amount, (int __user *)arg);
}
default:
return -ENOIOCTLCMD;
}
return 0;
}
EXPORT_SYMBOL(udp_ioctl);
struct sk_buff *__skb_recv_udp(struct sock *sk, unsigned int flags,
int noblock, int *peeked, int *off, int *err)
{
struct sk_buff_head *sk_queue = &sk->sk_receive_queue;
struct sk_buff_head *queue;
struct sk_buff *last;
long timeo;
int error;
queue = &udp_sk(sk)->reader_queue;
flags |= noblock ? MSG_DONTWAIT : 0;
timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
do {
struct sk_buff *skb;
error = sock_error(sk);
if (error)
break;
error = -EAGAIN;
*peeked = 0;
do {
spin_lock_bh(&queue->lock);
skb = __skb_try_recv_from_queue(sk, queue, flags,
udp_skb_destructor,
peeked, off, err,
&last);
if (skb) {
spin_unlock_bh(&queue->lock);
return skb;
}
if (skb_queue_empty(sk_queue)) {
spin_unlock_bh(&queue->lock);
goto busy_check;
}
/* refill the reader queue and walk it again
* keep both queues locked to avoid re-acquiring
* the sk_receive_queue lock if fwd memory scheduling
* is needed.
*/
spin_lock(&sk_queue->lock);
skb_queue_splice_tail_init(sk_queue, queue);
skb = __skb_try_recv_from_queue(sk, queue, flags,
udp_skb_dtor_locked,
peeked, off, err,
&last);
spin_unlock(&sk_queue->lock);
spin_unlock_bh(&queue->lock);
if (skb)
return skb;
busy_check:
if (!sk_can_busy_loop(sk))
break;
sk_busy_loop(sk, flags & MSG_DONTWAIT);
} while (!skb_queue_empty(sk_queue));
/* sk_queue is empty, reader_queue may contain peeked packets */
} while (timeo &&
!__skb_wait_for_more_packets(sk, &error, &timeo,
(struct sk_buff *)sk_queue));
*err = error;
return NULL;
}
EXPORT_SYMBOL(__skb_recv_udp);
/*
* This should be easy, if there is something there we
* return it, otherwise we block.
*/
int udp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int noblock,
int flags, int *addr_len)
{
struct inet_sock *inet = inet_sk(sk);
DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
struct sk_buff *skb;
unsigned int ulen, copied;
int peeked, peeking, off;
int err;
int is_udplite = IS_UDPLITE(sk);
bool checksum_valid = false;
if (flags & MSG_ERRQUEUE)
return ip_recv_error(sk, msg, len, addr_len);
try_again:
peeking = flags & MSG_PEEK;
off = sk_peek_offset(sk, flags);
skb = __skb_recv_udp(sk, flags, noblock, &peeked, &off, &err);
if (!skb)
return err;
ulen = udp_skb_len(skb);
copied = len;
if (copied > ulen - off)
copied = ulen - off;
else if (copied < ulen)
msg->msg_flags |= MSG_TRUNC;
/*
* If checksum is needed at all, try to do it while copying the
* data. If the data is truncated, or if we only want a partial
* coverage checksum (UDP-Lite), do it before the copy.
*/
if (copied < ulen || peeking ||
(is_udplite && UDP_SKB_CB(skb)->partial_cov)) {
checksum_valid = udp_skb_csum_unnecessary(skb) ||
!__udp_lib_checksum_complete(skb);
if (!checksum_valid)
goto csum_copy_err;
}
if (checksum_valid || udp_skb_csum_unnecessary(skb)) {
if (udp_skb_is_linear(skb))
err = copy_linear_skb(skb, copied, off, &msg->msg_iter);
else
err = skb_copy_datagram_msg(skb, off, msg, copied);
} else {
err = skb_copy_and_csum_datagram_msg(skb, off, msg);
if (err == -EINVAL)
goto csum_copy_err;
}
if (unlikely(err)) {
if (!peeked) {
atomic_inc(&sk->sk_drops);
UDP_INC_STATS(sock_net(sk),
UDP_MIB_INERRORS, is_udplite);
}
kfree_skb(skb);
return err;
}
if (!peeked)
UDP_INC_STATS(sock_net(sk),
UDP_MIB_INDATAGRAMS, is_udplite);
sock_recv_ts_and_drops(msg, sk, skb);
/* Copy the address. */
if (sin) {
sin->sin_family = AF_INET;
sin->sin_port = udp_hdr(skb)->source;
sin->sin_addr.s_addr = ip_hdr(skb)->saddr;
memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
*addr_len = sizeof(*sin);
}
if (udp_sk(sk)->gro_enabled)
udp_cmsg_recv(msg, sk, skb);
if (inet->cmsg_flags)
ip_cmsg_recv_offset(msg, sk, skb, sizeof(struct udphdr), off);
err = copied;
if (flags & MSG_TRUNC)
err = ulen;
skb_consume_udp(sk, skb, peeking ? -err : err);
return err;
csum_copy_err:
if (!__sk_queue_drop_skb(sk, &udp_sk(sk)->reader_queue, skb, flags,
udp_skb_destructor)) {
UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
}
kfree_skb(skb);
/* starting over for a new packet, but check if we need to yield */
cond_resched();
msg->msg_flags &= ~MSG_TRUNC;
goto try_again;
}
int udp_pre_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len)
{
/* This check is replicated from __ip4_datagram_connect() and
* intended to prevent BPF program called below from accessing bytes
* that are out of the bound specified by user in addr_len.
*/
if (addr_len < sizeof(struct sockaddr_in))
return -EINVAL;
return BPF_CGROUP_RUN_PROG_INET4_CONNECT_LOCK(sk, uaddr);
}
EXPORT_SYMBOL(udp_pre_connect);
int __udp_disconnect(struct sock *sk, int flags)
{
struct inet_sock *inet = inet_sk(sk);
/*
* 1003.1g - break association.
*/
sk->sk_state = TCP_CLOSE;
inet->inet_daddr = 0;
inet->inet_dport = 0;
sock_rps_reset_rxhash(sk);
sk->sk_bound_dev_if = 0;
if (!(sk->sk_userlocks & SOCK_BINDADDR_LOCK))
inet_reset_saddr(sk);
if (!(sk->sk_userlocks & SOCK_BINDPORT_LOCK)) {
sk->sk_prot->unhash(sk);
inet->inet_sport = 0;
}
sk_dst_reset(sk);
return 0;
}
EXPORT_SYMBOL(__udp_disconnect);
int udp_disconnect(struct sock *sk, int flags)
{
lock_sock(sk);
__udp_disconnect(sk, flags);
release_sock(sk);
return 0;
}
EXPORT_SYMBOL(udp_disconnect);
void udp_lib_unhash(struct sock *sk)
{
if (sk_hashed(sk)) {
struct udp_table *udptable = sk->sk_prot->h.udp_table;
struct udp_hslot *hslot, *hslot2;
hslot = udp_hashslot(udptable, sock_net(sk),
udp_sk(sk)->udp_port_hash);
hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
spin_lock_bh(&hslot->lock);
if (rcu_access_pointer(sk->sk_reuseport_cb))
reuseport_detach_sock(sk);
if (sk_del_node_init_rcu(sk)) {
hslot->count--;
inet_sk(sk)->inet_num = 0;
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
spin_lock(&hslot2->lock);
hlist_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
hslot2->count--;
spin_unlock(&hslot2->lock);
}
spin_unlock_bh(&hslot->lock);
}
}
EXPORT_SYMBOL(udp_lib_unhash);
/*
* inet_rcv_saddr was changed, we must rehash secondary hash
*/
void udp_lib_rehash(struct sock *sk, u16 newhash)
{
if (sk_hashed(sk)) {
struct udp_table *udptable = sk->sk_prot->h.udp_table;
struct udp_hslot *hslot, *hslot2, *nhslot2;
hslot2 = udp_hashslot2(udptable, udp_sk(sk)->udp_portaddr_hash);
nhslot2 = udp_hashslot2(udptable, newhash);
udp_sk(sk)->udp_portaddr_hash = newhash;
if (hslot2 != nhslot2 ||
rcu_access_pointer(sk->sk_reuseport_cb)) {
hslot = udp_hashslot(udptable, sock_net(sk),
udp_sk(sk)->udp_port_hash);
/* we must lock primary chain too */
spin_lock_bh(&hslot->lock);
if (rcu_access_pointer(sk->sk_reuseport_cb))
reuseport_detach_sock(sk);
if (hslot2 != nhslot2) {
spin_lock(&hslot2->lock);
hlist_del_init_rcu(&udp_sk(sk)->udp_portaddr_node);
hslot2->count--;
spin_unlock(&hslot2->lock);
spin_lock(&nhslot2->lock);
hlist_add_head_rcu(&udp_sk(sk)->udp_portaddr_node,
&nhslot2->head);
nhslot2->count++;
spin_unlock(&nhslot2->lock);
}
spin_unlock_bh(&hslot->lock);
}
}
}
EXPORT_SYMBOL(udp_lib_rehash);
static void udp_v4_rehash(struct sock *sk)
{
u16 new_hash = ipv4_portaddr_hash(sock_net(sk),
inet_sk(sk)->inet_rcv_saddr,
inet_sk(sk)->inet_num);
udp_lib_rehash(sk, new_hash);
}
static int __udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
int rc;
if (inet_sk(sk)->inet_daddr) {
sock_rps_save_rxhash(sk, skb);
sk_mark_napi_id(sk, skb);
sk_incoming_cpu_update(sk);
} else {
sk_mark_napi_id_once(sk, skb);
}
rc = __udp_enqueue_schedule_skb(sk, skb);
if (rc < 0) {
int is_udplite = IS_UDPLITE(sk);
/* Note that an ENOMEM error is charged twice */
if (rc == -ENOMEM)
UDP_INC_STATS(sock_net(sk), UDP_MIB_RCVBUFERRORS,
is_udplite);
UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
kfree_skb(skb);
trace_udp_fail_queue_rcv_skb(rc, sk);
return -1;
}
return 0;
}
/* returns:
* -1: error
* 0: success
* >0: "udp encap" protocol resubmission
*
* Note that in the success and error cases, the skb is assumed to
* have either been requeued or freed.
*/
static int udp_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb)
{
struct udp_sock *up = udp_sk(sk);
int is_udplite = IS_UDPLITE(sk);
/*
* Charge it to the socket, dropping if the queue is full.
*/
if (!xfrm4_policy_check(sk, XFRM_POLICY_IN, skb))
goto drop;
nf_reset(skb);
if (static_branch_unlikely(&udp_encap_needed_key) && up->encap_type) {
int (*encap_rcv)(struct sock *sk, struct sk_buff *skb);
/*
* This is an encapsulation socket so pass the skb to
* the socket's udp_encap_rcv() hook. Otherwise, just
* fall through and pass this up the UDP socket.
* up->encap_rcv() returns the following value:
* =0 if skb was successfully passed to the encap
* handler or was discarded by it.
* >0 if skb should be passed on to UDP.
* <0 if skb should be resubmitted as proto -N
*/
/* if we're overly short, let UDP handle it */
encap_rcv = READ_ONCE(up->encap_rcv);
if (encap_rcv) {
int ret;
/* Verify checksum before giving to encap */
if (udp_lib_checksum_complete(skb))
goto csum_error;
ret = encap_rcv(sk, skb);
if (ret <= 0) {
__UDP_INC_STATS(sock_net(sk),
UDP_MIB_INDATAGRAMS,
is_udplite);
return -ret;
}
}
/* FALLTHROUGH -- it's a UDP Packet */
}
/*
* UDP-Lite specific tests, ignored on UDP sockets
*/
if ((is_udplite & UDPLITE_RECV_CC) && UDP_SKB_CB(skb)->partial_cov) {
/*
* MIB statistics other than incrementing the error count are
* disabled for the following two types of errors: these depend
* on the application settings, not on the functioning of the
* protocol stack as such.
*
* RFC 3828 here recommends (sec 3.3): "There should also be a
* way ... to ... at least let the receiving application block
* delivery of packets with coverage values less than a value
* provided by the application."
*/
if (up->pcrlen == 0) { /* full coverage was set */
net_dbg_ratelimited("UDPLite: partial coverage %d while full coverage %d requested\n",
UDP_SKB_CB(skb)->cscov, skb->len);
goto drop;
}
/* The next case involves violating the min. coverage requested
* by the receiver. This is subtle: if receiver wants x and x is
* greater than the buffersize/MTU then receiver will complain
* that it wants x while sender emits packets of smaller size y.
* Therefore the above ...()->partial_cov statement is essential.
*/
if (UDP_SKB_CB(skb)->cscov < up->pcrlen) {
net_dbg_ratelimited("UDPLite: coverage %d too small, need min %d\n",
UDP_SKB_CB(skb)->cscov, up->pcrlen);
goto drop;
}
}
prefetch(&sk->sk_rmem_alloc);
if (rcu_access_pointer(sk->sk_filter) &&
udp_lib_checksum_complete(skb))
goto csum_error;
if (sk_filter_trim_cap(sk, skb, sizeof(struct udphdr)))
goto drop;
udp_csum_pull_header(skb);
ipv4_pktinfo_prepare(sk, skb);
return __udp_queue_rcv_skb(sk, skb);
csum_error:
__UDP_INC_STATS(sock_net(sk), UDP_MIB_CSUMERRORS, is_udplite);
drop:
__UDP_INC_STATS(sock_net(sk), UDP_MIB_INERRORS, is_udplite);
atomic_inc(&sk->sk_drops);
kfree_skb(skb);
return -1;
}
static int udp_queue_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
struct sk_buff *next, *segs;
int ret;
if (likely(!udp_unexpected_gso(sk, skb)))
return udp_queue_rcv_one_skb(sk, skb);
BUILD_BUG_ON(sizeof(struct udp_skb_cb) > SKB_SGO_CB_OFFSET);
__skb_push(skb, -skb_mac_offset(skb));
segs = udp_rcv_segment(sk, skb, true);
for (skb = segs; skb; skb = next) {
next = skb->next;
__skb_pull(skb, skb_transport_offset(skb));
ret = udp_queue_rcv_one_skb(sk, skb);
if (ret > 0)
ip_protocol_deliver_rcu(dev_net(skb->dev), skb, -ret);
}
return 0;
}
/* For TCP sockets, sk_rx_dst is protected by socket lock
* For UDP, we use xchg() to guard against concurrent changes.
*/
bool udp_sk_rx_dst_set(struct sock *sk, struct dst_entry *dst)
{
struct dst_entry *old;
if (dst_hold_safe(dst)) {
old = xchg(&sk->sk_rx_dst, dst);
dst_release(old);
return old != dst;
}
return false;
}
EXPORT_SYMBOL(udp_sk_rx_dst_set);
/*
* Multicasts and broadcasts go to each listener.
*
* Note: called only from the BH handler context.
*/
static int __udp4_lib_mcast_deliver(struct net *net, struct sk_buff *skb,
struct udphdr *uh,
__be32 saddr, __be32 daddr,
struct udp_table *udptable,
int proto)
{
struct sock *sk, *first = NULL;
unsigned short hnum = ntohs(uh->dest);
struct udp_hslot *hslot = udp_hashslot(udptable, net, hnum);
unsigned int hash2 = 0, hash2_any = 0, use_hash2 = (hslot->count > 10);
unsigned int offset = offsetof(typeof(*sk), sk_node);
int dif = skb->dev->ifindex;
int sdif = inet_sdif(skb);
struct hlist_node *node;
struct sk_buff *nskb;
if (use_hash2) {
hash2_any = ipv4_portaddr_hash(net, htonl(INADDR_ANY), hnum) &
udptable->mask;
hash2 = ipv4_portaddr_hash(net, daddr, hnum) & udptable->mask;
start_lookup:
hslot = &udptable->hash2[hash2];
offset = offsetof(typeof(*sk), __sk_common.skc_portaddr_node);
}
sk_for_each_entry_offset_rcu(sk, node, &hslot->head, offset) {
if (!__udp_is_mcast_sock(net, sk, uh->dest, daddr,
uh->source, saddr, dif, sdif, hnum))
continue;
if (!first) {
first = sk;
continue;
}
nskb = skb_clone(skb, GFP_ATOMIC);
if (unlikely(!nskb)) {
atomic_inc(&sk->sk_drops);
__UDP_INC_STATS(net, UDP_MIB_RCVBUFERRORS,
IS_UDPLITE(sk));
__UDP_INC_STATS(net, UDP_MIB_INERRORS,
IS_UDPLITE(sk));
continue;
}
if (udp_queue_rcv_skb(sk, nskb) > 0)
consume_skb(nskb);
}
/* Also lookup *:port if we are using hash2 and haven't done so yet. */
if (use_hash2 && hash2 != hash2_any) {
hash2 = hash2_any;
goto start_lookup;
}
if (first) {
if (udp_queue_rcv_skb(first, skb) > 0)
consume_skb(skb);
} else {
kfree_skb(skb);
__UDP_INC_STATS(net, UDP_MIB_IGNOREDMULTI,
proto == IPPROTO_UDPLITE);
}
return 0;
}
/* Initialize UDP checksum. If exited with zero value (success),
* CHECKSUM_UNNECESSARY means, that no more checks are required.
* Otherwise, csum completion requires chacksumming packet body,
* including udp header and folding it to skb->csum.
*/
static inline int udp4_csum_init(struct sk_buff *skb, struct udphdr *uh,
int proto)
{
int err;
UDP_SKB_CB(skb)->partial_cov = 0;
UDP_SKB_CB(skb)->cscov = skb->len;
if (proto == IPPROTO_UDPLITE) {
err = udplite_checksum_init(skb, uh);
if (err)
return err;
if (UDP_SKB_CB(skb)->partial_cov) {
skb->csum = inet_compute_pseudo(skb, proto);
return 0;
}
}
/* Note, we are only interested in != 0 or == 0, thus the
* force to int.
*/
err = (__force int)skb_checksum_init_zero_check(skb, proto, uh->check,
inet_compute_pseudo);
if (err)
return err;
if (skb->ip_summed == CHECKSUM_COMPLETE && !skb->csum_valid) {
/* If SW calculated the value, we know it's bad */
if (skb->csum_complete_sw)
return 1;
/* HW says the value is bad. Let's validate that.
* skb->csum is no longer the full packet checksum,
* so don't treat it as such.
*/
skb_checksum_complete_unset(skb);
}
return 0;
}
/* wrapper for udp_queue_rcv_skb tacking care of csum conversion and
* return code conversion for ip layer consumption
*/
static int udp_unicast_rcv_skb(struct sock *sk, struct sk_buff *skb,
struct udphdr *uh)
{
int ret;
if (inet_get_convert_csum(sk) && uh->check && !IS_UDPLITE(sk))
skb_checksum_try_convert(skb, IPPROTO_UDP, uh->check,
inet_compute_pseudo);
ret = udp_queue_rcv_skb(sk, skb);
/* a return value > 0 means to resubmit the input, but
* it wants the return to be -protocol, or 0
*/
if (ret > 0)
return -ret;
return 0;
}
/*
* All we need to do is get the socket, and then do a checksum.
*/
int __udp4_lib_rcv(struct sk_buff *skb, struct udp_table *udptable,
int proto)
{
struct sock *sk;
struct udphdr *uh;
unsigned short ulen;
struct rtable *rt = skb_rtable(skb);
__be32 saddr, daddr;
struct net *net = dev_net(skb->dev);
/*
* Validate the packet.
*/
if (!pskb_may_pull(skb, sizeof(struct udphdr)))
goto drop; /* No space for header. */
uh = udp_hdr(skb);
ulen = ntohs(uh->len);
saddr = ip_hdr(skb)->saddr;
daddr = ip_hdr(skb)->daddr;
if (ulen > skb->len)
goto short_packet;
if (proto == IPPROTO_UDP) {
/* UDP validates ulen. */
if (ulen < sizeof(*uh) || pskb_trim_rcsum(skb, ulen))
goto short_packet;
uh = udp_hdr(skb);
}
if (udp4_csum_init(skb, uh, proto))
goto csum_error;
sk = skb_steal_sock(skb);
if (sk) {
struct dst_entry *dst = skb_dst(skb);
int ret;
if (unlikely(sk->sk_rx_dst != dst))
udp_sk_rx_dst_set(sk, dst);
ret = udp_unicast_rcv_skb(sk, skb, uh);
sock_put(sk);
return ret;
}
if (rt->rt_flags & (RTCF_BROADCAST|RTCF_MULTICAST))
return __udp4_lib_mcast_deliver(net, skb, uh,
saddr, daddr, udptable, proto);
sk = __udp4_lib_lookup_skb(skb, uh->source, uh->dest, udptable);
if (sk)
return udp_unicast_rcv_skb(sk, skb, uh);
if (!xfrm4_policy_check(NULL, XFRM_POLICY_IN, skb))
goto drop;
nf_reset(skb);
/* No socket. Drop packet silently, if checksum is wrong */
if (udp_lib_checksum_complete(skb))
goto csum_error;
__UDP_INC_STATS(net, UDP_MIB_NOPORTS, proto == IPPROTO_UDPLITE);
icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
/*
* Hmm. We got an UDP packet to a port to which we
* don't wanna listen. Ignore it.
*/
kfree_skb(skb);
return 0;
short_packet:
net_dbg_ratelimited("UDP%s: short packet: From %pI4:%u %d/%d to %pI4:%u\n",
proto == IPPROTO_UDPLITE ? "Lite" : "",
&saddr, ntohs(uh->source),
ulen, skb->len,
&daddr, ntohs(uh->dest));
goto drop;
csum_error:
/*
* RFC1122: OK. Discards the bad packet silently (as far as
* the network is concerned, anyway) as per 4.1.3.4 (MUST).
*/
net_dbg_ratelimited("UDP%s: bad checksum. From %pI4:%u to %pI4:%u ulen %d\n",
proto == IPPROTO_UDPLITE ? "Lite" : "",
&saddr, ntohs(uh->source), &daddr, ntohs(uh->dest),
ulen);
__UDP_INC_STATS(net, UDP_MIB_CSUMERRORS, proto == IPPROTO_UDPLITE);
drop:
__UDP_INC_STATS(net, UDP_MIB_INERRORS, proto == IPPROTO_UDPLITE);
kfree_skb(skb);
return 0;
}
/* We can only early demux multicast if there is a single matching socket.
* If more than one socket found returns NULL
*/
static struct sock *__udp4_lib_mcast_demux_lookup(struct net *net,
__be16 loc_port, __be32 loc_addr,
__be16 rmt_port, __be32 rmt_addr,
int dif, int sdif)
{
struct sock *sk, *result;
unsigned short hnum = ntohs(loc_port);
unsigned int slot = udp_hashfn(net, hnum, udp_table.mask);
struct udp_hslot *hslot = &udp_table.hash[slot];
/* Do not bother scanning a too big list */
if (hslot->count > 10)
return NULL;
result = NULL;
sk_for_each_rcu(sk, &hslot->head) {
if (__udp_is_mcast_sock(net, sk, loc_port, loc_addr,
rmt_port, rmt_addr, dif, sdif, hnum)) {
if (result)
return NULL;
result = sk;
}
}
return result;
}
/* For unicast we should only early demux connected sockets or we can
* break forwarding setups. The chains here can be long so only check
* if the first socket is an exact match and if not move on.
*/
static struct sock *__udp4_lib_demux_lookup(struct net *net,
__be16 loc_port, __be32 loc_addr,
__be16 rmt_port, __be32 rmt_addr,
int dif, int sdif)
{
unsigned short hnum = ntohs(loc_port);
unsigned int hash2 = ipv4_portaddr_hash(net, loc_addr, hnum);
unsigned int slot2 = hash2 & udp_table.mask;
struct udp_hslot *hslot2 = &udp_table.hash2[slot2];
INET_ADDR_COOKIE(acookie, rmt_addr, loc_addr);
const __portpair ports = INET_COMBINED_PORTS(rmt_port, hnum);
struct sock *sk;
udp_portaddr_for_each_entry_rcu(sk, &hslot2->head) {
if (INET_MATCH(sk, net, acookie, rmt_addr,
loc_addr, ports, dif, sdif))
return sk;
/* Only check first socket in chain */
break;
}
return NULL;
}
int udp_v4_early_demux(struct sk_buff *skb)
{
struct net *net = dev_net(skb->dev);
struct in_device *in_dev = NULL;
const struct iphdr *iph;
const struct udphdr *uh;
struct sock *sk = NULL;
struct dst_entry *dst;
int dif = skb->dev->ifindex;
int sdif = inet_sdif(skb);
int ours;
/* validate the packet */
if (!pskb_may_pull(skb, skb_transport_offset(skb) + sizeof(struct udphdr)))
return 0;
iph = ip_hdr(skb);
uh = udp_hdr(skb);
if (skb->pkt_type == PACKET_MULTICAST) {
in_dev = __in_dev_get_rcu(skb->dev);
if (!in_dev)
return 0;
ours = ip_check_mc_rcu(in_dev, iph->daddr, iph->saddr,
iph->protocol);
if (!ours)
return 0;
sk = __udp4_lib_mcast_demux_lookup(net, uh->dest, iph->daddr,
uh->source, iph->saddr,
dif, sdif);
} else if (skb->pkt_type == PACKET_HOST) {
sk = __udp4_lib_demux_lookup(net, uh->dest, iph->daddr,
uh->source, iph->saddr, dif, sdif);
}
if (!sk || !refcount_inc_not_zero(&sk->sk_refcnt))
return 0;
skb->sk = sk;
skb->destructor = sock_efree;
dst = READ_ONCE(sk->sk_rx_dst);
if (dst)
dst = dst_check(dst, 0);
if (dst) {
u32 itag = 0;
/* set noref for now.
* any place which wants to hold dst has to call
* dst_hold_safe()
*/
skb_dst_set_noref(skb, dst);
/* for unconnected multicast sockets we need to validate
* the source on each packet
*/
if (!inet_sk(sk)->inet_daddr && in_dev)
return ip_mc_validate_source(skb, iph->daddr,
iph->saddr, iph->tos,
skb->dev, in_dev, &itag);
}
return 0;
}
int udp_rcv(struct sk_buff *skb)
{
return __udp4_lib_rcv(skb, &udp_table, IPPROTO_UDP);
}
void udp_destroy_sock(struct sock *sk)
{
struct udp_sock *up = udp_sk(sk);
bool slow = lock_sock_fast(sk);
udp_flush_pending_frames(sk);
unlock_sock_fast(sk, slow);
if (static_branch_unlikely(&udp_encap_needed_key)) {
if (up->encap_type) {
void (*encap_destroy)(struct sock *sk);
encap_destroy = READ_ONCE(up->encap_destroy);
if (encap_destroy)
encap_destroy(sk);
}
if (up->encap_enabled)
static_branch_dec(&udp_encap_needed_key);
}
}
/*
* Socket option code for UDP
*/
int udp_lib_setsockopt(struct sock *sk, int level, int optname,
char __user *optval, unsigned int optlen,
int (*push_pending_frames)(struct sock *))
{
struct udp_sock *up = udp_sk(sk);
int val, valbool;
int err = 0;
int is_udplite = IS_UDPLITE(sk);
if (optlen < sizeof(int))
return -EINVAL;
if (get_user(val, (int __user *)optval))
return -EFAULT;
valbool = val ? 1 : 0;
switch (optname) {
case UDP_CORK:
if (val != 0) {
up->corkflag = 1;
} else {
up->corkflag = 0;
lock_sock(sk);
push_pending_frames(sk);
release_sock(sk);
}
break;
case UDP_ENCAP:
switch (val) {
case 0:
case UDP_ENCAP_ESPINUDP:
case UDP_ENCAP_ESPINUDP_NON_IKE:
up->encap_rcv = xfrm4_udp_encap_rcv;
/* FALLTHROUGH */
case UDP_ENCAP_L2TPINUDP:
up->encap_type = val;
lock_sock(sk);
udp_tunnel_encap_enable(sk->sk_socket);
release_sock(sk);
break;
default:
err = -ENOPROTOOPT;
break;
}
break;
case UDP_NO_CHECK6_TX:
up->no_check6_tx = valbool;
break;
case UDP_NO_CHECK6_RX:
up->no_check6_rx = valbool;
break;
case UDP_SEGMENT:
if (val < 0 || val > USHRT_MAX)
return -EINVAL;
up->gso_size = val;
break;
case UDP_GRO:
lock_sock(sk);
if (valbool)
udp_tunnel_encap_enable(sk->sk_socket);
up->gro_enabled = valbool;
release_sock(sk);
break;
/*
* UDP-Lite's partial checksum coverage (RFC 3828).
*/
/* The sender sets actual checksum coverage length via this option.
* The case coverage > packet length is handled by send module. */
case UDPLITE_SEND_CSCOV:
if (!is_udplite) /* Disable the option on UDP sockets */
return -ENOPROTOOPT;
if (val != 0 && val < 8) /* Illegal coverage: use default (8) */
val = 8;
else if (val > USHRT_MAX)
val = USHRT_MAX;
up->pcslen = val;
up->pcflag |= UDPLITE_SEND_CC;
break;
/* The receiver specifies a minimum checksum coverage value. To make
* sense, this should be set to at least 8 (as done below). If zero is
* used, this again means full checksum coverage. */
case UDPLITE_RECV_CSCOV:
if (!is_udplite) /* Disable the option on UDP sockets */
return -ENOPROTOOPT;
if (val != 0 && val < 8) /* Avoid silly minimal values. */
val = 8;
else if (val > USHRT_MAX)
val = USHRT_MAX;
up->pcrlen = val;
up->pcflag |= UDPLITE_RECV_CC;
break;
default:
err = -ENOPROTOOPT;
break;
}
return err;
}
EXPORT_SYMBOL(udp_lib_setsockopt);
int udp_setsockopt(struct sock *sk, int level, int optname,
char __user *optval, unsigned int optlen)
{
if (level == SOL_UDP || level == SOL_UDPLITE)
return udp_lib_setsockopt(sk, level, optname, optval, optlen,
udp_push_pending_frames);
return ip_setsockopt(sk, level, optname, optval, optlen);
}
#ifdef CONFIG_COMPAT
int compat_udp_setsockopt(struct sock *sk, int level, int optname,
char __user *optval, unsigned int optlen)
{
if (level == SOL_UDP || level == SOL_UDPLITE)
return udp_lib_setsockopt(sk, level, optname, optval, optlen,
udp_push_pending_frames);
return compat_ip_setsockopt(sk, level, optname, optval, optlen);
}
#endif
int udp_lib_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *optlen)
{
struct udp_sock *up = udp_sk(sk);
int val, len;
if (get_user(len, optlen))
return -EFAULT;
len = min_t(unsigned int, len, sizeof(int));
if (len < 0)
return -EINVAL;
switch (optname) {
case UDP_CORK:
val = up->corkflag;
break;
case UDP_ENCAP:
val = up->encap_type;
break;
case UDP_NO_CHECK6_TX:
val = up->no_check6_tx;
break;
case UDP_NO_CHECK6_RX:
val = up->no_check6_rx;
break;
case UDP_SEGMENT:
val = up->gso_size;
break;
/* The following two cannot be changed on UDP sockets, the return is
* always 0 (which corresponds to the full checksum coverage of UDP). */
case UDPLITE_SEND_CSCOV:
val = up->pcslen;
break;
case UDPLITE_RECV_CSCOV:
val = up->pcrlen;
break;
default:
return -ENOPROTOOPT;
}
if (put_user(len, optlen))
return -EFAULT;
if (copy_to_user(optval, &val, len))
return -EFAULT;
return 0;
}
EXPORT_SYMBOL(udp_lib_getsockopt);
int udp_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *optlen)
{
if (level == SOL_UDP || level == SOL_UDPLITE)
return udp_lib_getsockopt(sk, level, optname, optval, optlen);
return ip_getsockopt(sk, level, optname, optval, optlen);
}
#ifdef CONFIG_COMPAT
int compat_udp_getsockopt(struct sock *sk, int level, int optname,
char __user *optval, int __user *optlen)
{
if (level == SOL_UDP || level == SOL_UDPLITE)
return udp_lib_getsockopt(sk, level, optname, optval, optlen);
return compat_ip_getsockopt(sk, level, optname, optval, optlen);
}
#endif
/**
* udp_poll - wait for a UDP event.
* @file - file struct
* @sock - socket
* @wait - poll table
*
* This is same as datagram poll, except for the special case of
* blocking sockets. If application is using a blocking fd
* and a packet with checksum error is in the queue;
* then it could get return from select indicating data available
* but then block when reading it. Add special case code
* to work around these arguably broken applications.
*/
__poll_t udp_poll(struct file *file, struct socket *sock, poll_table *wait)
{
__poll_t mask = datagram_poll(file, sock, wait);
struct sock *sk = sock->sk;
if (!skb_queue_empty(&udp_sk(sk)->reader_queue))
mask |= EPOLLIN | EPOLLRDNORM;
/* Check for false positives due to checksum errors */
if ((mask & EPOLLRDNORM) && !(file->f_flags & O_NONBLOCK) &&
!(sk->sk_shutdown & RCV_SHUTDOWN) && first_packet_length(sk) == -1)
mask &= ~(EPOLLIN | EPOLLRDNORM);
return mask;
}
EXPORT_SYMBOL(udp_poll);
int udp_abort(struct sock *sk, int err)
{
lock_sock(sk);
sk->sk_err = err;
sk->sk_error_report(sk);
__udp_disconnect(sk, 0);
release_sock(sk);
return 0;
}
EXPORT_SYMBOL_GPL(udp_abort);
struct proto udp_prot = {
.name = "UDP",
.owner = THIS_MODULE,
.close = udp_lib_close,
.pre_connect = udp_pre_connect,
.co