1/*
2 *  ebt_log
3 *
4 *	Authors:
5 *	Bart De Schuymer <bdschuym@pandora.be>
6 *	Harald Welte <laforge@netfilter.org>
7 *
8 *  April, 2002
9 *
10 */
11
12#include <linux/in.h>
13#include <linux/netfilter_bridge/ebtables.h>
14#include <linux/netfilter_bridge/ebt_log.h>
15#include <linux/netfilter.h>
16#include <linux/module.h>
17#include <linux/ip.h>
18#include <linux/in.h>
19#include <linux/if_arp.h>
20#include <linux/spinlock.h>
21
22static DEFINE_SPINLOCK(ebt_log_lock);
23
24static int ebt_log_check(const char *tablename, unsigned int hookmask,
25   const struct ebt_entry *e, void *data, unsigned int datalen)
26{
27	struct ebt_log_info *info = (struct ebt_log_info *)data;
28
29	if (datalen != EBT_ALIGN(sizeof(struct ebt_log_info)))
30		return -EINVAL;
31	if (info->bitmask & ~EBT_LOG_MASK)
32		return -EINVAL;
33	if (info->loglevel >= 8)
34		return -EINVAL;
35	info->prefix[EBT_LOG_PREFIX_SIZE - 1] = '\0';
36	return 0;
37}
38
39struct tcpudphdr
40{
41	__be16 src;
42	__be16 dst;
43};
44
45struct arppayload
46{
47	unsigned char mac_src[ETH_ALEN];
48	unsigned char ip_src[4];
49	unsigned char mac_dst[ETH_ALEN];
50	unsigned char ip_dst[4];
51};
52
53static void print_MAC(unsigned char *p)
54{
55	int i;
56
57	for (i = 0; i < ETH_ALEN; i++, p++)
58		printk("%02x%c", *p, i == ETH_ALEN - 1 ? ' ':':');
59}
60
61#define myNIPQUAD(a) a[0], a[1], a[2], a[3]
62static void
63ebt_log_packet(unsigned int pf, unsigned int hooknum,
64   const struct sk_buff *skb, const struct net_device *in,
65   const struct net_device *out, const struct nf_loginfo *loginfo,
66   const char *prefix)
67{
68	unsigned int bitmask;
69
70	spin_lock_bh(&ebt_log_lock);
71	printk("<%c>%s IN=%s OUT=%s MAC source = ", '0' + loginfo->u.log.level,
72	       prefix, in ? in->name : "", out ? out->name : "");
73
74	print_MAC(eth_hdr(skb)->h_source);
75	printk("MAC dest = ");
76	print_MAC(eth_hdr(skb)->h_dest);
77
78	printk("proto = 0x%04x", ntohs(eth_hdr(skb)->h_proto));
79
80	if (loginfo->type == NF_LOG_TYPE_LOG)
81		bitmask = loginfo->u.log.logflags;
82	else
83		bitmask = NF_LOG_MASK;
84
85	if ((bitmask & EBT_LOG_IP) && eth_hdr(skb)->h_proto ==
86	   htons(ETH_P_IP)){
87		struct iphdr _iph, *ih;
88
89		ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
90		if (ih == NULL) {
91			printk(" INCOMPLETE IP header");
92			goto out;
93		}
94		printk(" IP SRC=%u.%u.%u.%u IP DST=%u.%u.%u.%u, IP "
95		       "tos=0x%02X, IP proto=%d", NIPQUAD(ih->saddr),
96		       NIPQUAD(ih->daddr), ih->tos, ih->protocol);
97		if (ih->protocol == IPPROTO_TCP ||
98		    ih->protocol == IPPROTO_UDP ||
99		    ih->protocol == IPPROTO_UDPLITE ||
100		    ih->protocol == IPPROTO_SCTP ||
101		    ih->protocol == IPPROTO_DCCP) {
102			struct tcpudphdr _ports, *pptr;
103
104			pptr = skb_header_pointer(skb, ih->ihl*4,
105						  sizeof(_ports), &_ports);
106			if (pptr == NULL) {
107				printk(" INCOMPLETE TCP/UDP header");
108				goto out;
109			}
110			printk(" SPT=%u DPT=%u", ntohs(pptr->src),
111			   ntohs(pptr->dst));
112		}
113		goto out;
114	}
115
116	if ((bitmask & EBT_LOG_ARP) &&
117	    ((eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) ||
118	     (eth_hdr(skb)->h_proto == htons(ETH_P_RARP)))) {
119		struct arphdr _arph, *ah;
120
121		ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
122		if (ah == NULL) {
123			printk(" INCOMPLETE ARP header");
124			goto out;
125		}
126		printk(" ARP HTYPE=%d, PTYPE=0x%04x, OPCODE=%d",
127		       ntohs(ah->ar_hrd), ntohs(ah->ar_pro),
128		       ntohs(ah->ar_op));
129
130		/* If it's for Ethernet and the lengths are OK,
131		 * then log the ARP payload */
132		if (ah->ar_hrd == htons(1) &&
133		    ah->ar_hln == ETH_ALEN &&
134		    ah->ar_pln == sizeof(__be32)) {
135			struct arppayload _arpp, *ap;
136
137			ap = skb_header_pointer(skb, sizeof(_arph),
138						sizeof(_arpp), &_arpp);
139			if (ap == NULL) {
140				printk(" INCOMPLETE ARP payload");
141				goto out;
142			}
143			printk(" ARP MAC SRC=");
144			print_MAC(ap->mac_src);
145			printk(" ARP IP SRC=%u.%u.%u.%u",
146			       myNIPQUAD(ap->ip_src));
147			printk(" ARP MAC DST=");
148			print_MAC(ap->mac_dst);
149			printk(" ARP IP DST=%u.%u.%u.%u",
150			       myNIPQUAD(ap->ip_dst));
151		}
152	}
153out:
154	printk("\n");
155	spin_unlock_bh(&ebt_log_lock);
156
157}
158
159static void ebt_log(const struct sk_buff *skb, unsigned int hooknr,
160   const struct net_device *in, const struct net_device *out,
161   const void *data, unsigned int datalen)
162{
163	struct ebt_log_info *info = (struct ebt_log_info *)data;
164	struct nf_loginfo li;
165
166	li.type = NF_LOG_TYPE_LOG;
167	li.u.log.level = info->loglevel;
168	li.u.log.logflags = info->bitmask;
169
170	if (info->bitmask & EBT_LOG_NFLOG)
171		nf_log_packet(PF_BRIDGE, hooknr, skb, in, out, &li,
172			      "%s", info->prefix);
173	else
174		ebt_log_packet(PF_BRIDGE, hooknr, skb, in, out, &li,
175			       info->prefix);
176}
177
178static struct ebt_watcher log =
179{
180	.name		= EBT_LOG_WATCHER,
181	.watcher	= ebt_log,
182	.check		= ebt_log_check,
183	.me		= THIS_MODULE,
184};
185
186static struct nf_logger ebt_log_logger = {
187	.name 		= "ebt_log",
188	.logfn		= &ebt_log_packet,
189	.me		= THIS_MODULE,
190};
191
192static int __init ebt_log_init(void)
193{
194	int ret;
195
196	ret = ebt_register_watcher(&log);
197	if (ret < 0)
198		return ret;
199	ret = nf_log_register(PF_BRIDGE, &ebt_log_logger);
200	if (ret < 0 && ret != -EEXIST)
201		ebt_unregister_watcher(&log);
202	return ret;
203}
204
205static void __exit ebt_log_fini(void)
206{
207	nf_log_unregister(&ebt_log_logger);
208	ebt_unregister_watcher(&log);
209}
210
211module_init(ebt_log_init);
212module_exit(ebt_log_fini);
213MODULE_LICENSE("GPL");
214