2 * (C) 2014 by Pablo Neira Ayuso <pablo@netfilter.org>
4 * Based on code from ebt_log from:
6 * Bart De Schuymer <bdschuym@pandora.be>
7 * Harald Welte <laforge@netfilter.org>
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
14 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16 #include <linux/kernel.h>
17 #include <linux/module.h>
18 #include <linux/spinlock.h>
19 #include <linux/skbuff.h>
20 #include <linux/if_arp.h>
22 #include <net/route.h>
24 #include <linux/netfilter.h>
25 #include <linux/netfilter/xt_LOG.h>
26 #include <net/netfilter/nf_log.h>
28 static struct nf_loginfo default_loginfo = {
29 .type = NF_LOG_TYPE_LOG,
32 .level = LOGLEVEL_NOTICE,
33 .logflags = NF_LOG_MASK,
39 unsigned char mac_src[ETH_ALEN];
40 unsigned char ip_src[4];
41 unsigned char mac_dst[ETH_ALEN];
42 unsigned char ip_dst[4];
45 static void dump_arp_packet(struct nf_log_buf *m,
46 const struct nf_loginfo *info,
47 const struct sk_buff *skb, unsigned int nhoff)
49 const struct arphdr *ah;
51 const struct arppayload *ap;
52 struct arppayload _arpp;
54 ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
56 nf_log_buf_add(m, "TRUNCATED");
59 nf_log_buf_add(m, "ARP HTYPE=%d PTYPE=0x%04x OPCODE=%d",
60 ntohs(ah->ar_hrd), ntohs(ah->ar_pro), ntohs(ah->ar_op));
62 /* If it's for Ethernet and the lengths are OK, then log the ARP
65 if (ah->ar_hrd != htons(1) ||
66 ah->ar_hln != ETH_ALEN ||
67 ah->ar_pln != sizeof(__be32))
70 ap = skb_header_pointer(skb, sizeof(_arph), sizeof(_arpp), &_arpp);
72 nf_log_buf_add(m, " INCOMPLETE [%Zu bytes]",
73 skb->len - sizeof(_arph));
76 nf_log_buf_add(m, " MACSRC=%pM IPSRC=%pI4 MACDST=%pM IPDST=%pI4",
77 ap->mac_src, ap->ip_src, ap->mac_dst, ap->ip_dst);
80 static void nf_log_arp_packet(struct net *net, u_int8_t pf,
81 unsigned int hooknum, const struct sk_buff *skb,
82 const struct net_device *in,
83 const struct net_device *out,
84 const struct nf_loginfo *loginfo,
89 /* FIXME: Disabled from containers until syslog ns is supported */
90 if (!net_eq(net, &init_net))
93 m = nf_log_buf_open();
96 loginfo = &default_loginfo;
98 nf_log_dump_packet_common(m, pf, hooknum, skb, in, out, loginfo,
100 dump_arp_packet(m, loginfo, skb, 0);
105 static struct nf_logger nf_arp_logger __read_mostly = {
106 .name = "nf_log_arp",
107 .type = NF_LOG_TYPE_LOG,
108 .logfn = nf_log_arp_packet,
112 static int __net_init nf_log_arp_net_init(struct net *net)
114 nf_log_set(net, NFPROTO_ARP, &nf_arp_logger);
118 static void __net_exit nf_log_arp_net_exit(struct net *net)
120 nf_log_unset(net, &nf_arp_logger);
123 static struct pernet_operations nf_log_arp_net_ops = {
124 .init = nf_log_arp_net_init,
125 .exit = nf_log_arp_net_exit,
128 static int __init nf_log_arp_init(void)
132 ret = register_pernet_subsys(&nf_log_arp_net_ops);
136 ret = nf_log_register(NFPROTO_ARP, &nf_arp_logger);
138 pr_err("failed to register logger\n");
145 unregister_pernet_subsys(&nf_log_arp_net_ops);
149 static void __exit nf_log_arp_exit(void)
151 unregister_pernet_subsys(&nf_log_arp_net_ops);
152 nf_log_unregister(&nf_arp_logger);
155 module_init(nf_log_arp_init);
156 module_exit(nf_log_arp_exit);
158 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
159 MODULE_DESCRIPTION("Netfilter ARP packet logging");
160 MODULE_LICENSE("GPL");
161 MODULE_ALIAS_NF_LOGGER(3, 0);