| /* IRC extension for TCP NAT alteration. |
| * |
| * (C) 2000-2001 by Harald Welte <laforge@gnumonks.org> |
| * (C) 2004 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation |
| * based on a copy of RR's ip_nat_ftp.c |
| * |
| * 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. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/moduleparam.h> |
| #include <linux/tcp.h> |
| #include <linux/kernel.h> |
| |
| #include <net/netfilter/nf_nat.h> |
| #include <net/netfilter/nf_nat_helper.h> |
| #include <net/netfilter/nf_nat_rule.h> |
| #include <net/netfilter/nf_conntrack_helper.h> |
| #include <net/netfilter/nf_conntrack_expect.h> |
| #include <linux/netfilter/nf_conntrack_irc.h> |
| |
| MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>"); |
| MODULE_DESCRIPTION("IRC (DCC) NAT helper"); |
| MODULE_LICENSE("GPL"); |
| MODULE_ALIAS("ip_nat_irc"); |
| |
| static unsigned int help(struct sk_buff *skb, |
| enum ip_conntrack_info ctinfo, |
| unsigned int matchoff, |
| unsigned int matchlen, |
| struct nf_conntrack_expect *exp) |
| { |
| char buffer[sizeof("4294967296 65635")]; |
| u_int32_t ip; |
| u_int16_t port; |
| unsigned int ret; |
| |
| /* Reply comes from server. */ |
| exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port; |
| exp->dir = IP_CT_DIR_REPLY; |
| exp->expectfn = nf_nat_follow_master; |
| |
| /* Try to get same port: if not, try to change it. */ |
| for (port = ntohs(exp->saved_proto.tcp.port); port != 0; port++) { |
| exp->tuple.dst.u.tcp.port = htons(port); |
| if (nf_ct_expect_related(exp) == 0) |
| break; |
| } |
| |
| if (port == 0) |
| return NF_DROP; |
| |
| ip = ntohl(exp->master->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip); |
| sprintf(buffer, "%u %u", ip, port); |
| pr_debug("nf_nat_irc: inserting '%s' == %pI4, port %u\n", |
| buffer, &ip, port); |
| |
| ret = nf_nat_mangle_tcp_packet(skb, exp->master, ctinfo, |
| matchoff, matchlen, buffer, |
| strlen(buffer)); |
| if (ret != NF_ACCEPT) |
| nf_ct_unexpect_related(exp); |
| return ret; |
| } |
| |
| static void __exit nf_nat_irc_fini(void) |
| { |
| rcu_assign_pointer(nf_nat_irc_hook, NULL); |
| synchronize_rcu(); |
| } |
| |
| static int __init nf_nat_irc_init(void) |
| { |
| BUG_ON(nf_nat_irc_hook != NULL); |
| rcu_assign_pointer(nf_nat_irc_hook, help); |
| return 0; |
| } |
| |
| /* Prior to 2.6.11, we had a ports param. No longer, but don't break users. */ |
| static int warn_set(const char *val, struct kernel_param *kp) |
| { |
| printk(KERN_INFO KBUILD_MODNAME |
| ": kernel >= 2.6.10 only uses 'ports' for conntrack modules\n"); |
| return 0; |
| } |
| module_param_call(ports, warn_set, NULL, NULL, 0); |
| |
| module_init(nf_nat_irc_init); |
| module_exit(nf_nat_irc_fini); |