net/netfilter/xt_LOG.c

   1 /*
   2  * This is a module which is used for logging packets.
   3  */
   4
   5 /* (C) 1999-2001 Paul `Rusty' Russell
   6  * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  14 #include <linux/module.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/if_arp.h>
  18 #include <linux/ip.h>
  19 #include <net/ipv6.h>
  20 #include <net/icmp.h>
  21 #include <net/udp.h>
  22 #include <net/tcp.h>
  23 #include <net/route.h>
  24
  25 #include <linux/netfilter.h>
  26 #include <linux/netfilter/x_tables.h>
  27 #include <linux/netfilter/xt_LOG.h>
  28 #include <linux/netfilter_ipv6/ip6_tables.h>
  29 #include <net/netfilter/nf_log.h>
  30
  31 static unsigned int
  32 log_tg(struct sk_buff *skb, const struct xt_action_param *par)
  33 {
  34         const struct xt_log_info *loginfo = par->targinfo;
  35         struct nf_loginfo li;
  36         struct net *net = par->net;
  37
  38         li.type = NF_LOG_TYPE_LOG;
  39         li.u.log.level = loginfo->level;
  40         li.u.log.logflags = loginfo->logflags;
  41
  42         nf_log_packet(net, par->family, par->hooknum, skb, par->in, par->out,
  43                       &li, "%s", loginfo->prefix);
  44         return XT_CONTINUE;
  45 }
  46
  47 static int log_tg_check(const struct xt_tgchk_param *par)
  48 {
  49         const struct xt_log_info *loginfo = par->targinfo;
  50
  51         if (par->family != NFPROTO_IPV4 && par->family != NFPROTO_IPV6)
  52                 return -EINVAL;
  53
  54         if (loginfo->level >= 8) {
  55                 pr_debug("level %u >= 8\n", loginfo->level);
  56                 return -EINVAL;
  57         }
  58
  59         if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
  60                 pr_debug("prefix is not null-terminated\n");
  61                 return -EINVAL;
  62         }
  63
  64         return nf_logger_find_get(par->family, NF_LOG_TYPE_LOG);
  65 }
  66
  67 static void log_tg_destroy(const struct xt_tgdtor_param *par)
  68 {
  69         nf_logger_put(par->family, NF_LOG_TYPE_LOG);
  70 }
  71
  72 static struct xt_target log_tg_regs[] __read_mostly = {
  73         {
  74                 .name           = "LOG",
  75                 .family         = NFPROTO_IPV4,
  76                 .target         = log_tg,
  77                 .targetsize     = sizeof(struct xt_log_info),
  78                 .checkentry     = log_tg_check,
  79                 .destroy        = log_tg_destroy,
  80                 .me             = THIS_MODULE,
  81         },
  82 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
  83         {
  84                 .name           = "LOG",
  85                 .family         = NFPROTO_IPV6,
  86                 .target         = log_tg,
  87                 .targetsize     = sizeof(struct xt_log_info),
  88                 .checkentry     = log_tg_check,
  89                 .destroy        = log_tg_destroy,
  90                 .me             = THIS_MODULE,
  91         },
  92 #endif
  93 };
  94
  95 static int __init log_tg_init(void)
  96 {
  97         return xt_register_targets(log_tg_regs, ARRAY_SIZE(log_tg_regs));
  98 }
  99
 100 static void __exit log_tg_exit(void)
 101 {
 102         xt_unregister_targets(log_tg_regs, ARRAY_SIZE(log_tg_regs));
 103 }
 104
 105 module_init(log_tg_init);
 106 module_exit(log_tg_exit);
 107
 108 MODULE_LICENSE("GPL");
 109 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
 110 MODULE_AUTHOR("Jan Rekorajski <baggins@pld.org.pl>");
 111 MODULE_DESCRIPTION("Xtables: IPv4/IPv6 packet logging");
 112 MODULE_ALIAS("ipt_LOG");
 113 MODULE_ALIAS("ip6t_LOG");