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(ARPHRD_ETHER
) ||
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 return nf_log_set(net
, NFPROTO_ARP
, &nf_arp_logger
);
117 static void __net_exit
nf_log_arp_net_exit(struct net
*net
)
119 nf_log_unset(net
, &nf_arp_logger
);
122 static struct pernet_operations nf_log_arp_net_ops
= {
123 .init
= nf_log_arp_net_init
,
124 .exit
= nf_log_arp_net_exit
,
127 static int __init
nf_log_arp_init(void)
131 ret
= register_pernet_subsys(&nf_log_arp_net_ops
);
135 ret
= nf_log_register(NFPROTO_ARP
, &nf_arp_logger
);
137 pr_err("failed to register logger\n");
144 unregister_pernet_subsys(&nf_log_arp_net_ops
);
148 static void __exit
nf_log_arp_exit(void)
150 unregister_pernet_subsys(&nf_log_arp_net_ops
);
151 nf_log_unregister(&nf_arp_logger
);
154 module_init(nf_log_arp_init
);
155 module_exit(nf_log_arp_exit
);
157 MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
158 MODULE_DESCRIPTION("Netfilter ARP packet logging");
159 MODULE_LICENSE("GPL");
160 MODULE_ALIAS_NF_LOGGER(3, 0);