net/netfilter/xt_NFLOG.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Copyright (c) 2006 Patrick McHardy <kaber@trash.net>
0004  */
0005
0006 #include <linux/module.h>
0007 #include <linux/init.h>
0008 #include <linux/skbuff.h>
0009
0010 #include <linux/netfilter/x_tables.h>
0011 #include <linux/netfilter/xt_NFLOG.h>
0012 #include <net/netfilter/nf_log.h>
0013
0014 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
0015 MODULE_DESCRIPTION("Xtables: packet logging to netlink using NFLOG");
0016 MODULE_LICENSE("GPL");
0017 MODULE_ALIAS("ipt_NFLOG");
0018 MODULE_ALIAS("ip6t_NFLOG");
0019
0020 static unsigned int
0021 nflog_tg(struct sk_buff *skb, const struct xt_action_param *par)
0022 {
0023     const struct xt_nflog_info *info = par->targinfo;
0024     struct net *net = xt_net(par);
0025     struct nf_loginfo li;
0026
0027     li.type          = NF_LOG_TYPE_ULOG;
0028     li.u.ulog.copy_len   = info->len;
0029     li.u.ulog.group      = info->group;
0030     li.u.ulog.qthreshold = info->threshold;
0031     li.u.ulog.flags      = 0;
0032
0033     if (info->flags & XT_NFLOG_F_COPY_LEN)
0034         li.u.ulog.flags |= NF_LOG_F_COPY_LEN;
0035
0036     nf_log_packet(net, xt_family(par), xt_hooknum(par), skb, xt_in(par),
0037               xt_out(par), &li, "%s", info->prefix);
0038
0039     return XT_CONTINUE;
0040 }
0041
0042 static int nflog_tg_check(const struct xt_tgchk_param *par)
0043 {
0044     const struct xt_nflog_info *info = par->targinfo;
0045     int ret;
0046
0047     if (info->flags & ~XT_NFLOG_MASK)
0048         return -EINVAL;
0049     if (info->prefix[sizeof(info->prefix) - 1] != '\0')
0050         return -EINVAL;
0051
0052     ret = nf_logger_find_get(par->family, NF_LOG_TYPE_ULOG);
0053     if (ret != 0 && !par->nft_compat) {
0054         request_module("%s", "nfnetlink_log");
0055
0056         ret = nf_logger_find_get(par->family, NF_LOG_TYPE_ULOG);
0057     }
0058
0059     return ret;
0060 }
0061
0062 static void nflog_tg_destroy(const struct xt_tgdtor_param *par)
0063 {
0064     nf_logger_put(par->family, NF_LOG_TYPE_ULOG);
0065 }
0066
0067 static struct xt_target nflog_tg_reg __read_mostly = {
0068     .name       = "NFLOG",
0069     .revision   = 0,
0070     .family     = NFPROTO_UNSPEC,
0071     .checkentry = nflog_tg_check,
0072     .destroy    = nflog_tg_destroy,
0073     .target     = nflog_tg,
0074     .targetsize = sizeof(struct xt_nflog_info),
0075     .me         = THIS_MODULE,
0076 };
0077
0078 static int __init nflog_tg_init(void)
0079 {
0080     return xt_register_target(&nflog_tg_reg);
0081 }
0082
0083 static void __exit nflog_tg_exit(void)
0084 {
0085     xt_unregister_target(&nflog_tg_reg);
0086 }
0087
0088 module_init(nflog_tg_init);
0089 module_exit(nflog_tg_exit);
0090 MODULE_SOFTDEP("pre: nfnetlink_log");