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#include <linux/module.h>
12#include <linux/ip.h>
13#include <linux/in.h>
14#include <linux/if_arp.h>
15#include <linux/spinlock.h>
16#include <net/netfilter/nf_log.h>
17#include <linux/ipv6.h>
18#include <net/ipv6.h>
19#include <linux/in6.h>
20#include <linux/netfilter/x_tables.h>
21#include <linux/netfilter_bridge/ebtables.h>
22#include <linux/netfilter_bridge/ebt_log.h>
23#include <linux/netfilter.h>
24
25static DEFINE_SPINLOCK(ebt_log_lock);
26
27static int ebt_log_tg_check(const struct xt_tgchk_param *par)
28{
29	struct ebt_log_info *info = par->targinfo;
30
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
54print_ports(const struct sk_buff *skb, uint8_t protocol, int offset)
55{
56	if (protocol == IPPROTO_TCP ||
57	    protocol == IPPROTO_UDP ||
58	    protocol == IPPROTO_UDPLITE ||
59	    protocol == IPPROTO_SCTP ||
60	    protocol == IPPROTO_DCCP) {
61		const struct tcpudphdr *pptr;
62		struct tcpudphdr _ports;
63
64		pptr = skb_header_pointer(skb, offset,
65					  sizeof(_ports), &_ports);
66		if (pptr == NULL) {
67			printk(" INCOMPLETE TCP/UDP header");
68			return;
69		}
70		printk(" SPT=%u DPT=%u", ntohs(pptr->src), ntohs(pptr->dst));
71	}
72}
73
74static void
75ebt_log_packet(struct net *net, u_int8_t pf, unsigned int hooknum,
76	       const struct sk_buff *skb, const struct net_device *in,
77	       const struct net_device *out, const struct nf_loginfo *loginfo,
78	       const char *prefix)
79{
80	unsigned int bitmask;
81
82	/* FIXME: Disabled from containers until syslog ns is supported */
83	if (!net_eq(net, &init_net))
84		return;
85
86	spin_lock_bh(&ebt_log_lock);
87	printk(KERN_SOH "%c%s IN=%s OUT=%s MAC source = %pM MAC dest = %pM proto = 0x%04x",
88	       '0' + loginfo->u.log.level, prefix,
89	       in ? in->name : "", out ? out->name : "",
90	       eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
91	       ntohs(eth_hdr(skb)->h_proto));
92
93	if (loginfo->type == NF_LOG_TYPE_LOG)
94		bitmask = loginfo->u.log.logflags;
95	else
96		bitmask = NF_LOG_MASK;
97
98	if ((bitmask & EBT_LOG_IP) && eth_hdr(skb)->h_proto ==
99	   htons(ETH_P_IP)) {
100		const struct iphdr *ih;
101		struct iphdr _iph;
102
103		ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
104		if (ih == NULL) {
105			printk(" INCOMPLETE IP header");
106			goto out;
107		}
108		printk(" IP SRC=%pI4 IP DST=%pI4, IP tos=0x%02X, IP proto=%d",
109		       &ih->saddr, &ih->daddr, ih->tos, ih->protocol);
110		print_ports(skb, ih->protocol, ih->ihl*4);
111		goto out;
112	}
113
114#if IS_ENABLED(CONFIG_BRIDGE_EBT_IP6)
115	if ((bitmask & EBT_LOG_IP6) && eth_hdr(skb)->h_proto ==
116	   htons(ETH_P_IPV6)) {
117		const struct ipv6hdr *ih;
118		struct ipv6hdr _iph;
119		uint8_t nexthdr;
120		__be16 frag_off;
121		int offset_ph;
122
123		ih = skb_header_pointer(skb, 0, sizeof(_iph), &_iph);
124		if (ih == NULL) {
125			printk(" INCOMPLETE IPv6 header");
126			goto out;
127		}
128		printk(" IPv6 SRC=%pI6 IPv6 DST=%pI6, IPv6 priority=0x%01X, Next Header=%d",
129		       &ih->saddr, &ih->daddr, ih->priority, ih->nexthdr);
130		nexthdr = ih->nexthdr;
131		offset_ph = ipv6_skip_exthdr(skb, sizeof(_iph), &nexthdr, &frag_off);
132		if (offset_ph == -1)
133			goto out;
134		print_ports(skb, nexthdr, offset_ph);
135		goto out;
136	}
137#endif
138
139	if ((bitmask & EBT_LOG_ARP) &&
140	    ((eth_hdr(skb)->h_proto == htons(ETH_P_ARP)) ||
141	     (eth_hdr(skb)->h_proto == htons(ETH_P_RARP)))) {
142		const struct arphdr *ah;
143		struct arphdr _arph;
144
145		ah = skb_header_pointer(skb, 0, sizeof(_arph), &_arph);
146		if (ah == NULL) {
147			printk(" INCOMPLETE ARP header");
148			goto out;
149		}
150		printk(" ARP HTYPE=%d, PTYPE=0x%04x, OPCODE=%d",
151		       ntohs(ah->ar_hrd), ntohs(ah->ar_pro),
152		       ntohs(ah->ar_op));
153
154		/* If it's for Ethernet and the lengths are OK,
155		 * then log the ARP payload */
156		if (ah->ar_hrd == htons(1) &&
157		    ah->ar_hln == ETH_ALEN &&
158		    ah->ar_pln == sizeof(__be32)) {
159			const struct arppayload *ap;
160			struct arppayload _arpp;
161
162			ap = skb_header_pointer(skb, sizeof(_arph),
163						sizeof(_arpp), &_arpp);
164			if (ap == NULL) {
165				printk(" INCOMPLETE ARP payload");
166				goto out;
167			}
168			printk(" ARP MAC SRC=%pM ARP IP SRC=%pI4 ARP MAC DST=%pM ARP IP DST=%pI4",
169					ap->mac_src, ap->ip_src, ap->mac_dst, ap->ip_dst);
170		}
171	}
172out:
173	printk("\n");
174	spin_unlock_bh(&ebt_log_lock);
175
176}
177
178static unsigned int
179ebt_log_tg(struct sk_buff *skb, const struct xt_action_param *par)
180{
181	const struct ebt_log_info *info = par->targinfo;
182	struct nf_loginfo li;
183	struct net *net = dev_net(par->in ? par->in : par->out);
184
185	li.type = NF_LOG_TYPE_LOG;
186	li.u.log.level = info->loglevel;
187	li.u.log.logflags = info->bitmask;
188
189	/* Remember that we have to use ebt_log_packet() not to break backward
190	 * compatibility. We cannot use the default bridge packet logger via
191	 * nf_log_packet() with NFT_LOG_TYPE_LOG here. --Pablo
192	 */
193	if (info->bitmask & EBT_LOG_NFLOG)
194		nf_log_packet(net, NFPROTO_BRIDGE, par->hooknum, skb,
195			      par->in, par->out, &li, "%s", info->prefix);
196	else
197		ebt_log_packet(net, NFPROTO_BRIDGE, par->hooknum, skb, par->in,
198			       par->out, &li, info->prefix);
199	return EBT_CONTINUE;
200}
201
202static struct xt_target ebt_log_tg_reg __read_mostly = {
203	.name		= "log",
204	.revision	= 0,
205	.family		= NFPROTO_BRIDGE,
206	.target		= ebt_log_tg,
207	.checkentry	= ebt_log_tg_check,
208	.targetsize	= sizeof(struct ebt_log_info),
209	.me		= THIS_MODULE,
210};
211
212static int __init ebt_log_init(void)
213{
214	return xt_register_target(&ebt_log_tg_reg);
215}
216
217static void __exit ebt_log_fini(void)
218{
219	xt_unregister_target(&ebt_log_tg_reg);
220}
221
222module_init(ebt_log_init);
223module_exit(ebt_log_fini);
224MODULE_DESCRIPTION("Ebtables: Packet logging to syslog");
225MODULE_LICENSE("GPL");
226