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Based on 1 normalized pattern(s): 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 extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
122 lines
3.4 KiB
C
122 lines
3.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/* IRC extension for TCP NAT alteration.
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*
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* (C) 2000-2001 by Harald Welte <laforge@gnumonks.org>
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* (C) 2004 Rusty Russell <rusty@rustcorp.com.au> IBM Corporation
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* based on a copy of RR's ip_nat_ftp.c
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/tcp.h>
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#include <linux/kernel.h>
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#include <net/netfilter/nf_nat.h>
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#include <net/netfilter/nf_nat_helper.h>
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#include <net/netfilter/nf_conntrack_helper.h>
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#include <net/netfilter/nf_conntrack_expect.h>
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#include <linux/netfilter/nf_conntrack_irc.h>
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#define NAT_HELPER_NAME "irc"
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MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
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MODULE_DESCRIPTION("IRC (DCC) NAT helper");
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_NF_NAT_HELPER(NAT_HELPER_NAME);
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static struct nf_conntrack_nat_helper nat_helper_irc =
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NF_CT_NAT_HELPER_INIT(NAT_HELPER_NAME);
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static unsigned int help(struct sk_buff *skb,
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enum ip_conntrack_info ctinfo,
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unsigned int protoff,
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unsigned int matchoff,
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unsigned int matchlen,
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struct nf_conntrack_expect *exp)
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{
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char buffer[sizeof("4294967296 65635")];
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struct nf_conn *ct = exp->master;
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union nf_inet_addr newaddr;
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u_int16_t port;
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/* Reply comes from server. */
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newaddr = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3;
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exp->saved_proto.tcp.port = exp->tuple.dst.u.tcp.port;
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exp->dir = IP_CT_DIR_REPLY;
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exp->expectfn = nf_nat_follow_master;
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/* Try to get same port: if not, try to change it. */
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for (port = ntohs(exp->saved_proto.tcp.port); port != 0; port++) {
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int ret;
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exp->tuple.dst.u.tcp.port = htons(port);
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ret = nf_ct_expect_related(exp);
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if (ret == 0)
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break;
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else if (ret != -EBUSY) {
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port = 0;
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break;
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}
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}
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if (port == 0) {
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nf_ct_helper_log(skb, ct, "all ports in use");
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return NF_DROP;
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}
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/* strlen("\1DCC CHAT chat AAAAAAAA P\1\n")=27
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* strlen("\1DCC SCHAT chat AAAAAAAA P\1\n")=28
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* strlen("\1DCC SEND F AAAAAAAA P S\1\n")=26
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* strlen("\1DCC MOVE F AAAAAAAA P S\1\n")=26
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* strlen("\1DCC TSEND F AAAAAAAA P S\1\n")=27
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*
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* AAAAAAAAA: bound addr (1.0.0.0==16777216, min 8 digits,
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* 255.255.255.255==4294967296, 10 digits)
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* P: bound port (min 1 d, max 5d (65635))
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* F: filename (min 1 d )
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* S: size (min 1 d )
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* 0x01, \n: terminators
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*/
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/* AAA = "us", ie. where server normally talks to. */
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snprintf(buffer, sizeof(buffer), "%u %u", ntohl(newaddr.ip), port);
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pr_debug("inserting '%s' == %pI4, port %u\n",
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buffer, &newaddr.ip, port);
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if (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo, protoff, matchoff,
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matchlen, buffer, strlen(buffer))) {
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nf_ct_helper_log(skb, ct, "cannot mangle packet");
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nf_ct_unexpect_related(exp);
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return NF_DROP;
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}
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return NF_ACCEPT;
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}
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static void __exit nf_nat_irc_fini(void)
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{
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nf_nat_helper_unregister(&nat_helper_irc);
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RCU_INIT_POINTER(nf_nat_irc_hook, NULL);
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synchronize_rcu();
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}
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static int __init nf_nat_irc_init(void)
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{
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BUG_ON(nf_nat_irc_hook != NULL);
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nf_nat_helper_register(&nat_helper_irc);
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RCU_INIT_POINTER(nf_nat_irc_hook, help);
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return 0;
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}
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/* Prior to 2.6.11, we had a ports param. No longer, but don't break users. */
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static int warn_set(const char *val, const struct kernel_param *kp)
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{
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pr_info("kernel >= 2.6.10 only uses 'ports' for conntrack modules\n");
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return 0;
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}
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module_param_call(ports, warn_set, NULL, NULL, 0);
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module_init(nf_nat_irc_init);
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module_exit(nf_nat_irc_fini);
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