cregit-Linux how code gets into the kernel

Release 4.8 net/netfilter/nf_nat_irc.c

Directory: net/netfilter
/* IRC extension for TCP NAT alteration.
 * (C) 2000-2001 by Harald Welte <>
 * (C) 2004 Rusty Russell <> 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_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_expect.h>
#include <linux/netfilter/nf_conntrack_irc.h>

MODULE_AUTHOR("Harald Welte <>");

static unsigned int help(struct sk_buff *skb, enum ip_conntrack_info ctinfo, unsigned int protoff, unsigned int matchoff, unsigned int matchlen, struct nf_conntrack_expect *exp) { char buffer[sizeof("4294967296 65635")]; struct nf_conn *ct = exp->master; union nf_inet_addr newaddr; u_int16_t port; unsigned int ret; /* Reply comes from server. */ newaddr = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3; 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++) { int ret; exp->tuple.dst.u.tcp.port = htons(port); ret = nf_ct_expect_related(exp); if (ret == 0) break; else if (ret != -EBUSY) { port = 0; break; } } if (port == 0) { nf_ct_helper_log(skb, ct, "all ports in use"); return NF_DROP; } /* strlen("\1DCC CHAT chat AAAAAAAA P\1\n")=27 * strlen("\1DCC SCHAT chat AAAAAAAA P\1\n")=28 * strlen("\1DCC SEND F AAAAAAAA P S\1\n")=26 * strlen("\1DCC MOVE F AAAAAAAA P S\1\n")=26 * strlen("\1DCC TSEND F AAAAAAAA P S\1\n")=27 * * AAAAAAAAA: bound addr (, min 8 digits, *, 10 digits) * P: bound port (min 1 d, max 5d (65635)) * F: filename (min 1 d ) * S: size (min 1 d ) * 0x01, \n: terminators */ /* AAA = "us", ie. where server normally talks to. */ snprintf(buffer, sizeof(buffer), "%u %u", ntohl(newaddr.ip), port); pr_debug("nf_nat_irc: inserting '%s' == %pI4, port %u\n", buffer, &newaddr.ip, port); ret = nf_nat_mangle_tcp_packet(skb, ct, ctinfo, protoff, matchoff, matchlen, buffer, strlen(buffer)); if (ret != NF_ACCEPT) { nf_ct_helper_log(skb, ct, "cannot mangle packet"); nf_ct_unexpect_related(exp); } return ret; }


patrick mchardypatrick mchardy17660.69%342.86%
daniel borkmanndaniel borkmann6823.45%114.29%
pablo neira ayusopablo neira ayuso4415.17%228.57%
herbert xuherbert xu20.69%114.29%

static void __exit nf_nat_irc_fini(void) { RCU_INIT_POINTER(nf_nat_irc_hook, NULL); synchronize_rcu(); }


patrick mchardypatrick mchardy1894.74%150.00%
stephen hemmingerstephen hemminger15.26%150.00%

static int __init nf_nat_irc_init(void) { BUG_ON(nf_nat_irc_hook != NULL); RCU_INIT_POINTER(nf_nat_irc_hook, help); return 0; }


patrick mchardypatrick mchardy2596.15%266.67%
stephen hemmingerstephen hemminger13.85%133.33%

/* 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; }


patrick mchardypatrick mchardy25100.00%1100.00%

module_param_call(ports, warn_set, NULL, NULL, 0); module_init(nf_nat_irc_init); module_exit(nf_nat_irc_fini);

Overall Contributors

patrick mchardypatrick mchardy31673.15%444.44%
daniel borkmanndaniel borkmann6815.74%111.11%
pablo neira ayusopablo neira ayuso4410.19%222.22%
herbert xuherbert xu20.46%111.11%
stephen hemmingerstephen hemminger20.46%111.11%
Directory: net/netfilter
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