net/netfilter/xt_NFLOG.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
   4  */
   5
   6 #include <linux/module.h>
   7 #include <linux/init.h>
   8 #include <linux/skbuff.h>
   9
  10 #include <linux/netfilter/x_tables.h>
  11 #include <linux/netfilter/xt_NFLOG.h>
  12 #include <net/netfilter/nf_log.h>
  13
  14 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
  15 MODULE_DESCRIPTION("Xtables: packet logging to netlink using NFLOG");
  16 MODULE_LICENSE("GPL");
  17 MODULE_ALIAS("ipt_NFLOG");
  18 MODULE_ALIAS("ip6t_NFLOG");
  19
  20 static unsigned int
  21 nflog_tg(struct sk_buff *skb, const struct xt_action_param *par)
  22 {
  23         const struct xt_nflog_info *info = par->targinfo;
  24         struct net *net = xt_net(par);
  25         struct nf_loginfo li;
  26
  27         li.type              = NF_LOG_TYPE_ULOG;
  28         li.u.ulog.copy_len   = info->len;
  29         li.u.ulog.group      = info->group;
  30         li.u.ulog.qthreshold = info->threshold;
  31         li.u.ulog.flags      = 0;
  32
  33         if (info->flags & XT_NFLOG_F_COPY_LEN)
  34                 li.u.ulog.flags |= NF_LOG_F_COPY_LEN;
  35
  36         nf_log_packet(net, xt_family(par), xt_hooknum(par), skb, xt_in(par),
  37                       xt_out(par), &li, "%s", info->prefix);
  38
  39         return XT_CONTINUE;
  40 }
  41
  42 static int nflog_tg_check(const struct xt_tgchk_param *par)
  43 {
  44         const struct xt_nflog_info *info = par->targinfo;
  45         int ret;
  46
  47         if (info->flags & ~XT_NFLOG_MASK)
  48                 return -EINVAL;
  49         if (info->prefix[sizeof(info->prefix) - 1] != '\0')
  50                 return -EINVAL;
  51
  52         ret = nf_logger_find_get(par->family, NF_LOG_TYPE_ULOG);
  53         if (ret != 0 && !par->nft_compat) {
  54                 request_module("%s", "nfnetlink_log");
  55
  56                 ret = nf_logger_find_get(par->family, NF_LOG_TYPE_ULOG);
  57         }
  58
  59         return ret;
  60 }
  61
  62 static void nflog_tg_destroy(const struct xt_tgdtor_param *par)
  63 {
  64         nf_logger_put(par->family, NF_LOG_TYPE_ULOG);
  65 }
  66
  67 static struct xt_target nflog_tg_reg __read_mostly = {
  68         .name       = "NFLOG",
  69         .revision   = 0,
  70         .family     = NFPROTO_UNSPEC,
  71         .checkentry = nflog_tg_check,
  72         .destroy    = nflog_tg_destroy,
  73         .target     = nflog_tg,
  74         .targetsize = sizeof(struct xt_nflog_info),
  75         .me         = THIS_MODULE,
  76 };
  77
  78 static int __init nflog_tg_init(void)
  79 {
  80         return xt_register_target(&nflog_tg_reg);
  81 }
  82
  83 static void __exit nflog_tg_exit(void)
  84 {
  85         xt_unregister_target(&nflog_tg_reg);
  86 }
  87
  88 module_init(nflog_tg_init);
  89 module_exit(nflog_tg_exit);
  90 MODULE_SOFTDEP("pre: nfnetlink_log");