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 const struct nf_loginfo default_loginfo = {
29 .type = NF_LOG_TYPE_LOG,
32 .level = LOGLEVEL_NOTICE,
33 .logflags = NF_LOG_DEFAULT_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 arppayload *ap;
50 struct arppayload _arpp;
51 const struct arphdr *ah;
52 unsigned int logflags;
55 ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
57 nf_log_buf_add(m, "TRUNCATED");
61 if (info->type == NF_LOG_TYPE_LOG)
62 logflags = info->u.log.logflags;
64 logflags = NF_LOG_DEFAULT_MASK;
66 if (logflags & NF_LOG_MACDECODE) {
67 nf_log_buf_add(m, "MACSRC=%pM MACDST=%pM ",
68 eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest);
69 nf_log_dump_vlan(m, skb);
70 nf_log_buf_add(m, "MACPROTO=%04x ",
71 ntohs(eth_hdr(skb)->h_proto));
74 nf_log_buf_add(m, "ARP HTYPE=%d PTYPE=0x%04x OPCODE=%d",
75 ntohs(ah->ar_hrd), ntohs(ah->ar_pro), ntohs(ah->ar_op));
77 /* If it's for Ethernet and the lengths are OK, then log the ARP
80 if (ah->ar_hrd != htons(ARPHRD_ETHER) ||
81 ah->ar_hln != ETH_ALEN ||
82 ah->ar_pln != sizeof(__be32))
85 ap = skb_header_pointer(skb, sizeof(_arph), sizeof(_arpp), &_arpp);
87 nf_log_buf_add(m, " INCOMPLETE [%zu bytes]",
88 skb->len - sizeof(_arph));
91 nf_log_buf_add(m, " MACSRC=%pM IPSRC=%pI4 MACDST=%pM IPDST=%pI4",
92 ap->mac_src, ap->ip_src, ap->mac_dst, ap->ip_dst);
95 static void nf_log_arp_packet(struct net *net, u_int8_t pf,
96 unsigned int hooknum, const struct sk_buff *skb,
97 const struct net_device *in,
98 const struct net_device *out,
99 const struct nf_loginfo *loginfo,
102 struct nf_log_buf *m;
104 /* FIXME: Disabled from containers until syslog ns is supported */
105 if (!net_eq(net, &init_net) && !sysctl_nf_log_all_netns)
108 m = nf_log_buf_open();
111 loginfo = &default_loginfo;
113 nf_log_dump_packet_common(m, pf, hooknum, skb, in, out, loginfo,
115 dump_arp_packet(m, loginfo, skb, 0);
120 static struct nf_logger nf_arp_logger __read_mostly = {
121 .name = "nf_log_arp",
122 .type = NF_LOG_TYPE_LOG,
123 .logfn = nf_log_arp_packet,
127 static int __net_init nf_log_arp_net_init(struct net *net)
129 return nf_log_set(net, NFPROTO_ARP, &nf_arp_logger);
132 static void __net_exit nf_log_arp_net_exit(struct net *net)
134 nf_log_unset(net, &nf_arp_logger);
137 static struct pernet_operations nf_log_arp_net_ops = {
138 .init = nf_log_arp_net_init,
139 .exit = nf_log_arp_net_exit,
142 static int __init nf_log_arp_init(void)
146 ret = register_pernet_subsys(&nf_log_arp_net_ops);
150 ret = nf_log_register(NFPROTO_ARP, &nf_arp_logger);
152 pr_err("failed to register logger\n");
159 unregister_pernet_subsys(&nf_log_arp_net_ops);
163 static void __exit nf_log_arp_exit(void)
165 unregister_pernet_subsys(&nf_log_arp_net_ops);
166 nf_log_unregister(&nf_arp_logger);
169 module_init(nf_log_arp_init);
170 module_exit(nf_log_arp_exit);
172 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
173 MODULE_DESCRIPTION("Netfilter ARP packet logging");
174 MODULE_LICENSE("GPL");
175 MODULE_ALIAS_NF_LOGGER(3, 0);