| /* Amanda extension for IP connection tracking, Version 0.2 |
| * (C) 2002 by Brian J. Murrell <netfilter@interlinx.bc.ca> |
| * based on HW's ip_conntrack_irc.c as well as other modules |
| * |
| * 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. |
| * |
| * Module load syntax: |
| * insmod ip_conntrack_amanda.o [master_timeout=n] |
| * |
| * Where master_timeout is the timeout (in seconds) of the master |
| * connection (port 10080). This defaults to 5 minutes but if |
| * your clients take longer than 5 minutes to do their work |
| * before getting back to the Amanda server, you can increase |
| * this value. |
| * |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/netfilter.h> |
| #include <linux/ip.h> |
| #include <linux/moduleparam.h> |
| #include <net/checksum.h> |
| #include <net/udp.h> |
| |
| #include <linux/netfilter_ipv4/lockhelp.h> |
| #include <linux/netfilter_ipv4/ip_conntrack_helper.h> |
| #include <linux/netfilter_ipv4/ip_conntrack_amanda.h> |
| |
| static unsigned int master_timeout = 300; |
| |
| MODULE_AUTHOR("Brian J. Murrell <netfilter@interlinx.bc.ca>"); |
| MODULE_DESCRIPTION("Amanda connection tracking module"); |
| MODULE_LICENSE("GPL"); |
| module_param(master_timeout, int, 0600); |
| MODULE_PARM_DESC(master_timeout, "timeout for the master connection"); |
| |
| static char *conns[] = { "DATA ", "MESG ", "INDEX " }; |
| |
| /* This is slow, but it's simple. --RR */ |
| static char amanda_buffer[65536]; |
| static DECLARE_LOCK(amanda_buffer_lock); |
| |
| unsigned int (*ip_nat_amanda_hook)(struct sk_buff **pskb, |
| enum ip_conntrack_info ctinfo, |
| unsigned int matchoff, |
| unsigned int matchlen, |
| struct ip_conntrack_expect *exp); |
| EXPORT_SYMBOL_GPL(ip_nat_amanda_hook); |
| |
| static int help(struct sk_buff **pskb, |
| struct ip_conntrack *ct, enum ip_conntrack_info ctinfo) |
| { |
| struct ip_conntrack_expect *exp; |
| char *data, *data_limit, *tmp; |
| unsigned int dataoff, i; |
| u_int16_t port, len; |
| int ret = NF_ACCEPT; |
| |
| /* Only look at packets from the Amanda server */ |
| if (CTINFO2DIR(ctinfo) == IP_CT_DIR_ORIGINAL) |
| return NF_ACCEPT; |
| |
| /* increase the UDP timeout of the master connection as replies from |
| * Amanda clients to the server can be quite delayed */ |
| ip_ct_refresh_acct(ct, ctinfo, NULL, master_timeout * HZ); |
| |
| /* No data? */ |
| dataoff = (*pskb)->nh.iph->ihl*4 + sizeof(struct udphdr); |
| if (dataoff >= (*pskb)->len) { |
| if (net_ratelimit()) |
| printk("amanda_help: skblen = %u\n", (*pskb)->len); |
| return NF_ACCEPT; |
| } |
| |
| LOCK_BH(&amanda_buffer_lock); |
| skb_copy_bits(*pskb, dataoff, amanda_buffer, (*pskb)->len - dataoff); |
| data = amanda_buffer; |
| data_limit = amanda_buffer + (*pskb)->len - dataoff; |
| *data_limit = '\0'; |
| |
| /* Search for the CONNECT string */ |
| data = strstr(data, "CONNECT "); |
| if (!data) |
| goto out; |
| data += strlen("CONNECT "); |
| |
| /* Only search first line. */ |
| if ((tmp = strchr(data, '\n'))) |
| *tmp = '\0'; |
| |
| for (i = 0; i < ARRAY_SIZE(conns); i++) { |
| char *match = strstr(data, conns[i]); |
| if (!match) |
| continue; |
| tmp = data = match + strlen(conns[i]); |
| port = simple_strtoul(data, &data, 10); |
| len = data - tmp; |
| if (port == 0 || len > 5) |
| break; |
| |
| exp = ip_conntrack_expect_alloc(); |
| if (exp == NULL) { |
| ret = NF_DROP; |
| goto out; |
| } |
| |
| exp->expectfn = NULL; |
| exp->master = ct; |
| |
| exp->tuple.src.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip; |
| exp->tuple.src.u.tcp.port = 0; |
| exp->tuple.dst.ip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.ip; |
| exp->tuple.dst.protonum = IPPROTO_TCP; |
| exp->tuple.dst.u.tcp.port = htons(port); |
| |
| exp->mask.src.ip = 0xFFFFFFFF; |
| exp->mask.src.u.tcp.port = 0; |
| exp->mask.dst.ip = 0xFFFFFFFF; |
| exp->mask.dst.protonum = 0xFF; |
| exp->mask.dst.u.tcp.port = 0xFFFF; |
| |
| if (ip_nat_amanda_hook) |
| ret = ip_nat_amanda_hook(pskb, ctinfo, |
| tmp - amanda_buffer, |
| len, exp); |
| else if (ip_conntrack_expect_related(exp) != 0) { |
| ip_conntrack_expect_free(exp); |
| ret = NF_DROP; |
| } |
| } |
| |
| out: |
| UNLOCK_BH(&amanda_buffer_lock); |
| return ret; |
| } |
| |
| static struct ip_conntrack_helper amanda_helper = { |
| .max_expected = ARRAY_SIZE(conns), |
| .timeout = 180, |
| .me = THIS_MODULE, |
| .help = help, |
| .name = "amanda", |
| |
| .tuple = { .src = { .u = { __constant_htons(10080) } }, |
| .dst = { .protonum = IPPROTO_UDP }, |
| }, |
| .mask = { .src = { .u = { 0xFFFF } }, |
| .dst = { .protonum = 0xFF }, |
| }, |
| }; |
| |
| static void __exit fini(void) |
| { |
| ip_conntrack_helper_unregister(&amanda_helper); |
| } |
| |
| static int __init init(void) |
| { |
| return ip_conntrack_helper_register(&amanda_helper); |
| } |
| |
| module_init(init); |
| module_exit(fini); |