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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
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
155
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
190
191
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
