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13#include <linux/module.h>
14#include <linux/spinlock.h>
15#include <linux/skbuff.h>
16#include <linux/ip.h>
17#include <net/icmp.h>
18#include <net/udp.h>
19#include <net/tcp.h>
20#include <net/route.h>
21
22#include <linux/netfilter.h>
23#include <linux/netfilter/x_tables.h>
24#include <linux/netfilter_ipv4/ipt_LOG.h>
25#include <net/netfilter/nf_log.h>
26
27MODULE_LICENSE("GPL");
28MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
29MODULE_DESCRIPTION("Xtables: IPv4 packet logging to syslog");
30
31
32static DEFINE_SPINLOCK(log_lock);
33
34
35static void dump_packet(const struct nf_loginfo *info,
36 const struct sk_buff *skb,
37 unsigned int iphoff)
38{
39 struct iphdr _iph;
40 const struct iphdr *ih;
41 unsigned int logflags;
42
43 if (info->type == NF_LOG_TYPE_LOG)
44 logflags = info->u.log.logflags;
45 else
46 logflags = NF_LOG_MASK;
47
48 ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph);
49 if (ih == NULL) {
50 printk("TRUNCATED");
51 return;
52 }
53
54
55
56
57 printk("SRC=%pI4 DST=%pI4 ",
58 &ih->saddr, &ih->daddr);
59
60
61 printk("LEN=%u TOS=0x%02X PREC=0x%02X TTL=%u ID=%u ",
62 ntohs(ih->tot_len), ih->tos & IPTOS_TOS_MASK,
63 ih->tos & IPTOS_PREC_MASK, ih->ttl, ntohs(ih->id));
64
65
66 if (ntohs(ih->frag_off) & IP_CE)
67 printk("CE ");
68 if (ntohs(ih->frag_off) & IP_DF)
69 printk("DF ");
70 if (ntohs(ih->frag_off) & IP_MF)
71 printk("MF ");
72
73
74 if (ntohs(ih->frag_off) & IP_OFFSET)
75 printk("FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET);
76
77 if ((logflags & IPT_LOG_IPOPT)
78 && ih->ihl * 4 > sizeof(struct iphdr)) {
79 const unsigned char *op;
80 unsigned char _opt[4 * 15 - sizeof(struct iphdr)];
81 unsigned int i, optsize;
82
83 optsize = ih->ihl * 4 - sizeof(struct iphdr);
84 op = skb_header_pointer(skb, iphoff+sizeof(_iph),
85 optsize, _opt);
86 if (op == NULL) {
87 printk("TRUNCATED");
88 return;
89 }
90
91
92 printk("OPT (");
93 for (i = 0; i < optsize; i++)
94 printk("%02X", op[i]);
95 printk(") ");
96 }
97
98 switch (ih->protocol) {
99 case IPPROTO_TCP: {
100 struct tcphdr _tcph;
101 const struct tcphdr *th;
102
103
104 printk("PROTO=TCP ");
105
106 if (ntohs(ih->frag_off) & IP_OFFSET)
107 break;
108
109
110 th = skb_header_pointer(skb, iphoff + ih->ihl * 4,
111 sizeof(_tcph), &_tcph);
112 if (th == NULL) {
113 printk("INCOMPLETE [%u bytes] ",
114 skb->len - iphoff - ih->ihl*4);
115 break;
116 }
117
118
119 printk("SPT=%u DPT=%u ",
120 ntohs(th->source), ntohs(th->dest));
121
122 if (logflags & IPT_LOG_TCPSEQ)
123 printk("SEQ=%u ACK=%u ",
124 ntohl(th->seq), ntohl(th->ack_seq));
125
126 printk("WINDOW=%u ", ntohs(th->window));
127
128 printk("RES=0x%02x ", (u8)(ntohl(tcp_flag_word(th) & TCP_RESERVED_BITS) >> 22));
129
130 if (th->cwr)
131 printk("CWR ");
132 if (th->ece)
133 printk("ECE ");
134 if (th->urg)
135 printk("URG ");
136 if (th->ack)
137 printk("ACK ");
138 if (th->psh)
139 printk("PSH ");
140 if (th->rst)
141 printk("RST ");
142 if (th->syn)
143 printk("SYN ");
144 if (th->fin)
145 printk("FIN ");
146
147 printk("URGP=%u ", ntohs(th->urg_ptr));
148
149 if ((logflags & IPT_LOG_TCPOPT)
150 && th->doff * 4 > sizeof(struct tcphdr)) {
151 unsigned char _opt[4 * 15 - sizeof(struct tcphdr)];
152 const unsigned char *op;
153 unsigned int i, optsize;
154
155 optsize = th->doff * 4 - sizeof(struct tcphdr);
156 op = skb_header_pointer(skb,
157 iphoff+ih->ihl*4+sizeof(_tcph),
158 optsize, _opt);
159 if (op == NULL) {
160 printk("TRUNCATED");
161 return;
162 }
163
164
165 printk("OPT (");
166 for (i = 0; i < optsize; i++)
167 printk("%02X", op[i]);
168 printk(") ");
169 }
170 break;
171 }
172 case IPPROTO_UDP:
173 case IPPROTO_UDPLITE: {
174 struct udphdr _udph;
175 const struct udphdr *uh;
176
177 if (ih->protocol == IPPROTO_UDP)
178
179 printk("PROTO=UDP " );
180 else
181 printk("PROTO=UDPLITE ");
182
183 if (ntohs(ih->frag_off) & IP_OFFSET)
184 break;
185
186
187 uh = skb_header_pointer(skb, iphoff+ih->ihl*4,
188 sizeof(_udph), &_udph);
189 if (uh == NULL) {
190 printk("INCOMPLETE [%u bytes] ",
191 skb->len - iphoff - ih->ihl*4);
192 break;
193 }
194
195
196 printk("SPT=%u DPT=%u LEN=%u ",
197 ntohs(uh->source), ntohs(uh->dest),
198 ntohs(uh->len));
199 break;
200 }
201 case IPPROTO_ICMP: {
202 struct icmphdr _icmph;
203 const struct icmphdr *ich;
204 static const size_t required_len[NR_ICMP_TYPES+1]
205 = { [ICMP_ECHOREPLY] = 4,
206 [ICMP_DEST_UNREACH]
207 = 8 + sizeof(struct iphdr),
208 [ICMP_SOURCE_QUENCH]
209 = 8 + sizeof(struct iphdr),
210 [ICMP_REDIRECT]
211 = 8 + sizeof(struct iphdr),
212 [ICMP_ECHO] = 4,
213 [ICMP_TIME_EXCEEDED]
214 = 8 + sizeof(struct iphdr),
215 [ICMP_PARAMETERPROB]
216 = 8 + sizeof(struct iphdr),
217 [ICMP_TIMESTAMP] = 20,
218 [ICMP_TIMESTAMPREPLY] = 20,
219 [ICMP_ADDRESS] = 12,
220 [ICMP_ADDRESSREPLY] = 12 };
221
222
223 printk("PROTO=ICMP ");
224
225 if (ntohs(ih->frag_off) & IP_OFFSET)
226 break;
227
228
229 ich = skb_header_pointer(skb, iphoff + ih->ihl * 4,
230 sizeof(_icmph), &_icmph);
231 if (ich == NULL) {
232 printk("INCOMPLETE [%u bytes] ",
233 skb->len - iphoff - ih->ihl*4);
234 break;
235 }
236
237
238 printk("TYPE=%u CODE=%u ", ich->type, ich->code);
239
240
241 if (ich->type <= NR_ICMP_TYPES
242 && required_len[ich->type]
243 && skb->len-iphoff-ih->ihl*4 < required_len[ich->type]) {
244 printk("INCOMPLETE [%u bytes] ",
245 skb->len - iphoff - ih->ihl*4);
246 break;
247 }
248
249 switch (ich->type) {
250 case ICMP_ECHOREPLY:
251 case ICMP_ECHO:
252
253 printk("ID=%u SEQ=%u ",
254 ntohs(ich->un.echo.id),
255 ntohs(ich->un.echo.sequence));
256 break;
257
258 case ICMP_PARAMETERPROB:
259
260 printk("PARAMETER=%u ",
261 ntohl(ich->un.gateway) >> 24);
262 break;
263 case ICMP_REDIRECT:
264
265 printk("GATEWAY=%pI4 ", &ich->un.gateway);
266
267 case ICMP_DEST_UNREACH:
268 case ICMP_SOURCE_QUENCH:
269 case ICMP_TIME_EXCEEDED:
270
271 if (!iphoff) {
272 printk("[");
273 dump_packet(info, skb,
274 iphoff + ih->ihl*4+sizeof(_icmph));
275 printk("] ");
276 }
277
278
279 if (ich->type == ICMP_DEST_UNREACH
280 && ich->code == ICMP_FRAG_NEEDED)
281 printk("MTU=%u ", ntohs(ich->un.frag.mtu));
282 }
283 break;
284 }
285
286 case IPPROTO_AH: {
287 struct ip_auth_hdr _ahdr;
288 const struct ip_auth_hdr *ah;
289
290 if (ntohs(ih->frag_off) & IP_OFFSET)
291 break;
292
293
294 printk("PROTO=AH ");
295
296
297 ah = skb_header_pointer(skb, iphoff+ih->ihl*4,
298 sizeof(_ahdr), &_ahdr);
299 if (ah == NULL) {
300 printk("INCOMPLETE [%u bytes] ",
301 skb->len - iphoff - ih->ihl*4);
302 break;
303 }
304
305
306 printk("SPI=0x%x ", ntohl(ah->spi));
307 break;
308 }
309 case IPPROTO_ESP: {
310 struct ip_esp_hdr _esph;
311 const struct ip_esp_hdr *eh;
312
313
314 printk("PROTO=ESP ");
315
316 if (ntohs(ih->frag_off) & IP_OFFSET)
317 break;
318
319
320 eh = skb_header_pointer(skb, iphoff+ih->ihl*4,
321 sizeof(_esph), &_esph);
322 if (eh == NULL) {
323 printk("INCOMPLETE [%u bytes] ",
324 skb->len - iphoff - ih->ihl*4);
325 break;
326 }
327
328
329 printk("SPI=0x%x ", ntohl(eh->spi));
330 break;
331 }
332
333 default:
334 printk("PROTO=%u ", ih->protocol);
335 }
336
337
338 if ((logflags & IPT_LOG_UID) && !iphoff && skb->sk) {
339 read_lock_bh(&skb->sk->sk_callback_lock);
340 if (skb->sk->sk_socket && skb->sk->sk_socket->file)
341 printk("UID=%u GID=%u ",
342 skb->sk->sk_socket->file->f_cred->fsuid,
343 skb->sk->sk_socket->file->f_cred->fsgid);
344 read_unlock_bh(&skb->sk->sk_callback_lock);
345 }
346
347
348 if (!iphoff && skb->mark)
349 printk("MARK=0x%x ", skb->mark);
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364}
365
366static struct nf_loginfo default_loginfo = {
367 .type = NF_LOG_TYPE_LOG,
368 .u = {
369 .log = {
370 .level = 0,
371 .logflags = NF_LOG_MASK,
372 },
373 },
374};
375
376static void
377ipt_log_packet(u_int8_t pf,
378 unsigned int hooknum,
379 const struct sk_buff *skb,
380 const struct net_device *in,
381 const struct net_device *out,
382 const struct nf_loginfo *loginfo,
383 const char *prefix)
384{
385 if (!loginfo)
386 loginfo = &default_loginfo;
387
388 spin_lock_bh(&log_lock);
389 printk("<%d>%sIN=%s OUT=%s ", loginfo->u.log.level,
390 prefix,
391 in ? in->name : "",
392 out ? out->name : "");
393#ifdef CONFIG_BRIDGE_NETFILTER
394 if (skb->nf_bridge) {
395 const struct net_device *physindev;
396 const struct net_device *physoutdev;
397
398 physindev = skb->nf_bridge->physindev;
399 if (physindev && in != physindev)
400 printk("PHYSIN=%s ", physindev->name);
401 physoutdev = skb->nf_bridge->physoutdev;
402 if (physoutdev && out != physoutdev)
403 printk("PHYSOUT=%s ", physoutdev->name);
404 }
405#endif
406
407 if (in && !out) {
408
409 printk("MAC=");
410 if (skb->dev && skb->dev->hard_header_len
411 && skb->mac_header != skb->network_header) {
412 int i;
413 const unsigned char *p = skb_mac_header(skb);
414 for (i = 0; i < skb->dev->hard_header_len; i++,p++)
415 printk("%02x%c", *p,
416 i==skb->dev->hard_header_len - 1
417 ? ' ':':');
418 } else
419 printk(" ");
420 }
421
422 dump_packet(loginfo, skb, 0);
423 printk("\n");
424 spin_unlock_bh(&log_lock);
425}
426
427static unsigned int
428log_tg(struct sk_buff *skb, const struct xt_target_param *par)
429{
430 const struct ipt_log_info *loginfo = par->targinfo;
431 struct nf_loginfo li;
432
433 li.type = NF_LOG_TYPE_LOG;
434 li.u.log.level = loginfo->level;
435 li.u.log.logflags = loginfo->logflags;
436
437 ipt_log_packet(NFPROTO_IPV4, par->hooknum, skb, par->in, par->out, &li,
438 loginfo->prefix);
439 return XT_CONTINUE;
440}
441
442static bool log_tg_check(const struct xt_tgchk_param *par)
443{
444 const struct ipt_log_info *loginfo = par->targinfo;
445
446 if (loginfo->level >= 8) {
447 pr_debug("LOG: level %u >= 8\n", loginfo->level);
448 return false;
449 }
450 if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
451 pr_debug("LOG: prefix term %i\n",
452 loginfo->prefix[sizeof(loginfo->prefix)-1]);
453 return false;
454 }
455 return true;
456}
457
458static struct xt_target log_tg_reg __read_mostly = {
459 .name = "LOG",
460 .family = NFPROTO_IPV4,
461 .target = log_tg,
462 .targetsize = sizeof(struct ipt_log_info),
463 .checkentry = log_tg_check,
464 .me = THIS_MODULE,
465};
466
467static struct nf_logger ipt_log_logger __read_mostly = {
468 .name = "ipt_LOG",
469 .logfn = &ipt_log_packet,
470 .me = THIS_MODULE,
471};
472
473static int __init log_tg_init(void)
474{
475 int ret;
476
477 ret = xt_register_target(&log_tg_reg);
478 if (ret < 0)
479 return ret;
480 nf_log_register(NFPROTO_IPV4, &ipt_log_logger);
481 return 0;
482}
483
484static void __exit log_tg_exit(void)
485{
486 nf_log_unregister(&ipt_log_logger);
487 xt_unregister_target(&log_tg_reg);
488}
489
490module_init(log_tg_init);
491module_exit(log_tg_exit);
492
