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NETFILTER: remove unnecessary goto statement for error recovery
[tomato.git] / release / src-rt / linux / linux-2.6 / net / ipv4 / netfilter / ipt_LOG.c
blob08fa1493d5ecabcddadc92822f6ac13e88ceec80
1 /*
2 * This is a module which is used for logging packets.
3 */
4
5 /* (C) 1999-2001 Paul `Rusty' Russell
6 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
7 *
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
11 */
12
13 #include <linux/module.h>
14 #include <linux/spinlock.h>
15 #include <linux/skbuff.h>
16 #include <linux/if_arp.h>
17 #include <linux/ip.h>
18 #include <net/icmp.h>
19 #include <net/udp.h>
20 #include <net/tcp.h>
21 #include <net/route.h>
22
23 #include <linux/netfilter.h>
24 #include <linux/netfilter/x_tables.h>
25 #include <linux/netfilter_ipv4/ipt_LOG.h>
26 #include <net/netfilter/xt_log.h>
27
28 MODULE_LICENSE("GPL");
29 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
30 MODULE_DESCRIPTION("Xtables: IPv4 packet logging to syslog");
31
32 #if 0
33 #define DEBUGP printk
34 #else
35 #define DEBUGP(format, args...)
36 #endif
37
38 /* One level of recursion won't kill us */
39 static void dump_packet(struct sbuff *m,
40 const struct nf_loginfo *info,
41 const struct sk_buff *skb,
42 unsigned int iphoff)
43 {
44 struct iphdr _iph, *ih;
45 unsigned int logflags;
46
47 if (info->type == NF_LOG_TYPE_LOG)
48 logflags = info->u.log.logflags;
49 else
50 logflags = NF_LOG_MASK;
51
52 ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph);
53 if (ih == NULL) {
54 sb_add(m, "TRUNCATED");
55 return;
56 }
57
58 /* Important fields:
59 * TOS, len, DF/MF, fragment offset, TTL, src, dst, options. */
60 /* Max length: 40 "SRC=255.255.255.255 DST=255.255.255.255 " */
61 sb_add(m, "SRC=%u.%u.%u.%u DST=%u.%u.%u.%u ",
62 NIPQUAD(ih->saddr), NIPQUAD(ih->daddr));
63
64 /* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */
65 sb_add(m, "LEN=%u TOS=0x%02X PREC=0x%02X TTL=%u ID=%u ",
66 ntohs(ih->tot_len), ih->tos & IPTOS_TOS_MASK,
67 ih->tos & IPTOS_PREC_MASK, ih->ttl, ntohs(ih->id));
68
69 /* Max length: 6 "CE DF MF " */
70 if (ntohs(ih->frag_off) & IP_CE)
71 sb_add(m, "CE ");
72 if (ntohs(ih->frag_off) & IP_DF)
73 sb_add(m, "DF ");
74 if (ntohs(ih->frag_off) & IP_MF)
75 sb_add(m, "MF ");
76
77 /* Max length: 11 "FRAG:65535 " */
78 if (ntohs(ih->frag_off) & IP_OFFSET)
79 sb_add(m, "FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET);
80
81 if ((logflags & IPT_LOG_IPOPT)
82 && ih->ihl * 4 > sizeof(struct iphdr)) {
83 unsigned char _opt[4 * 15 - sizeof(struct iphdr)], *op;
84 unsigned int i, optsize;
85
86 optsize = ih->ihl * 4 - sizeof(struct iphdr);
87 op = skb_header_pointer(skb, iphoff+sizeof(_iph),
88 optsize, _opt);
89 if (op == NULL) {
90 sb_add(m, "TRUNCATED");
91 return;
92 }
93
94 /* Max length: 127 "OPT (" 15*4*2chars ") " */
95 sb_add(m, "OPT (");
96 for (i = 0; i < optsize; i++)
97 sb_add(m, "%02X", op[i]);
98 sb_add(m, ") ");
99 }
100
101 switch (ih->protocol) {
102 case IPPROTO_TCP: {
103 struct tcphdr _tcph, *th;
104
105 /* Max length: 10 "PROTO=TCP " */
106 sb_add(m, "PROTO=TCP ");
107
108 if (ntohs(ih->frag_off) & IP_OFFSET)
109 break;
110
111 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
112 th = skb_header_pointer(skb, iphoff + ih->ihl * 4,
113 sizeof(_tcph), &_tcph);
114 if (th == NULL) {
115 sb_add(m, "INCOMPLETE [%u bytes] ",
116 skb->len - iphoff - ih->ihl*4);
117 break;
118 }
119
120 /* Max length: 20 "SPT=65535 DPT=65535 " */
121 sb_add(m, "SPT=%u DPT=%u ",
122 ntohs(th->source), ntohs(th->dest));
123 /* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
124 if (logflags & IPT_LOG_TCPSEQ)
125 sb_add(m, "SEQ=%u ACK=%u ",
126 ntohl(th->seq), ntohl(th->ack_seq));
127 /* Max length: 13 "WINDOW=65535 " */
128 sb_add(m, "WINDOW=%u ", ntohs(th->window));
129 /* Max length: 9 "RES=0x3F " */
130 sb_add(m, "RES=0x%02x ", (u8)(ntohl(tcp_flag_word(th) & TCP_RESERVED_BITS) >> 22));
131 /* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
132 if (th->cwr)
133 sb_add(m, "CWR ");
134 if (th->ece)
135 sb_add(m, "ECE ");
136 if (th->urg)
137 sb_add(m, "URG ");
138 if (th->ack)
139 sb_add(m, "ACK ");
140 if (th->psh)
141 sb_add(m, "PSH ");
142 if (th->rst)
143 sb_add(m, "RST ");
144 if (th->syn)
145 sb_add(m, "SYN ");
146 if (th->fin)
147 sb_add(m, "FIN ");
148 /* Max length: 11 "URGP=65535 " */
149 sb_add(m, "URGP=%u ", ntohs(th->urg_ptr));
150
151 if ((logflags & IPT_LOG_TCPOPT)
152 && th->doff * 4 > sizeof(struct tcphdr)) {
153 unsigned char _opt[4 * 15 - sizeof(struct tcphdr)];
154 unsigned char *op;
155 unsigned int i, optsize;
156
157 optsize = th->doff * 4 - sizeof(struct tcphdr);
158 op = skb_header_pointer(skb,
159 iphoff+ih->ihl*4+sizeof(_tcph),
160 optsize, _opt);
161 if (op == NULL) {
162 sb_add(m, "TRUNCATED");
163 return;
164 }
165
166 /* Max length: 127 "OPT (" 15*4*2chars ") " */
167 sb_add(m, "OPT (");
168 for (i = 0; i < optsize; i++)
169 sb_add(m, "%02X", op[i]);
170 sb_add(m, ") ");
171 }
172 break;
173 }
174 case IPPROTO_UDP:
175 case IPPROTO_UDPLITE: {
176 struct udphdr _udph, *uh;
177
178 if (ih->protocol == IPPROTO_UDP)
179 /* Max length: 10 "PROTO=UDP " */
180 sb_add(m, "PROTO=UDP " );
181 else /* Max length: 14 "PROTO=UDPLITE " */
182 sb_add(m, "PROTO=UDPLITE ");
183
184 if (ntohs(ih->frag_off) & IP_OFFSET)
185 break;
186
187 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
188 uh = skb_header_pointer(skb, iphoff+ih->ihl*4,
189 sizeof(_udph), &_udph);
190 if (uh == NULL) {
191 sb_add(m, "INCOMPLETE [%u bytes] ",
192 skb->len - iphoff - ih->ihl*4);
193 break;
194 }
195
196 /* Max length: 20 "SPT=65535 DPT=65535 " */
197 sb_add(m, "SPT=%u DPT=%u LEN=%u ",
198 ntohs(uh->source), ntohs(uh->dest),
199 ntohs(uh->len));
200 break;
201 }
202 case IPPROTO_ICMP: {
203 struct icmphdr _icmph, *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 /* Max length: 11 "PROTO=ICMP " */
223 sb_add(m, "PROTO=ICMP ");
224
225 if (ntohs(ih->frag_off) & IP_OFFSET)
226 break;
227
228 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
229 ich = skb_header_pointer(skb, iphoff + ih->ihl * 4,
230 sizeof(_icmph), &_icmph);
231 if (ich == NULL) {
232 sb_add(m, "INCOMPLETE [%u bytes] ",
233 skb->len - iphoff - ih->ihl*4);
234 break;
235 }
236
237 /* Max length: 18 "TYPE=255 CODE=255 " */
238 sb_add(m, "TYPE=%u CODE=%u ", ich->type, ich->code);
239
240 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
241 if (ich->type <= NR_ICMP_TYPES
242 && required_len[ich->type]
243 && skb->len-iphoff-ih->ihl*4 < required_len[ich->type]) {
244 sb_add(m, "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 /* Max length: 19 "ID=65535 SEQ=65535 " */
253 sb_add(m, "ID=%u SEQ=%u ",
254 ntohs(ich->un.echo.id),
255 ntohs(ich->un.echo.sequence));
256 break;
257
258 case ICMP_PARAMETERPROB:
259 /* Max length: 14 "PARAMETER=255 " */
260 sb_add(m, "PARAMETER=%u ",
261 ntohl(ich->un.gateway) >> 24);
262 break;
263 case ICMP_REDIRECT:
264 /* Max length: 24 "GATEWAY=255.255.255.255 " */
265 sb_add(m, "GATEWAY=%u.%u.%u.%u ",
266 NIPQUAD(ich->un.gateway));
267 /* Fall through */
268 case ICMP_DEST_UNREACH:
269 case ICMP_SOURCE_QUENCH:
270 case ICMP_TIME_EXCEEDED:
271 /* Max length: 3+maxlen */
272 if (!iphoff) { /* Only recurse once. */
273 sb_add(m, "[");
274 dump_packet(m, info, skb,
275 iphoff + ih->ihl*4+sizeof(_icmph));
276 sb_add(m, "] ");
277 }
278
279 /* Max length: 10 "MTU=65535 " */
280 if (ich->type == ICMP_DEST_UNREACH
281 && ich->code == ICMP_FRAG_NEEDED)
282 sb_add(m, "MTU=%u ", ntohs(ich->un.frag.mtu));
283 }
284 break;
285 }
286 /* Max Length */
287 case IPPROTO_AH: {
288 struct ip_auth_hdr _ahdr, *ah;
289
290 if (ntohs(ih->frag_off) & IP_OFFSET)
291 break;
292
293 /* Max length: 9 "PROTO=AH " */
294 sb_add(m, "PROTO=AH ");
295
296 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
297 ah = skb_header_pointer(skb, iphoff+ih->ihl*4,
298 sizeof(_ahdr), &_ahdr);
299 if (ah == NULL) {
300 sb_add(m, "INCOMPLETE [%u bytes] ",
301 skb->len - iphoff - ih->ihl*4);
302 break;
303 }
304
305 /* Length: 15 "SPI=0xF1234567 " */
306 sb_add(m, "SPI=0x%x ", ntohl(ah->spi));
307 break;
308 }
309 case IPPROTO_ESP: {
310 struct ip_esp_hdr _esph, *eh;
311
312 /* Max length: 10 "PROTO=ESP " */
313 sb_add(m, "PROTO=ESP ");
314
315 if (ntohs(ih->frag_off) & IP_OFFSET)
316 break;
317
318 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
319 eh = skb_header_pointer(skb, iphoff+ih->ihl*4,
320 sizeof(_esph), &_esph);
321 if (eh == NULL) {
322 sb_add(m, "INCOMPLETE [%u bytes] ",
323 skb->len - iphoff - ih->ihl*4);
324 break;
325 }
326
327 /* Length: 15 "SPI=0xF1234567 " */
328 sb_add(m, "SPI=0x%x ", ntohl(eh->spi));
329 break;
330 }
331 /* Max length: 10 "PROTO 255 " */
332 default:
333 sb_add(m, "PROTO=%u ", ih->protocol);
334 }
335
336 /* Max length: 15 "UID=4294967295 " */
337 if ((logflags & IPT_LOG_UID) && !iphoff && skb->sk) {
338 read_lock_bh(&skb->sk->sk_callback_lock);
339 if (skb->sk->sk_socket && skb->sk->sk_socket->file)
340 sb_add(m, "UID=%u GID=%u ",
341 skb->sk->sk_socket->file->f_uid,
342 skb->sk->sk_socket->file->f_gid);
343 read_unlock_bh(&skb->sk->sk_callback_lock);
344 }
345
346 /* Max length: 16 "MARK=0xFFFFFFFF " */
347 if (!iphoff && skb->mark)
348 sb_add(m, "MARK=0x%x ", skb->mark);
349
350 /* Proto Max log string length */
351 /* IP: 40+46+6+11+127 = 230 */
352 /* TCP: 10+max(25,20+30+13+9+32+11+127) = 252 */
353 /* UDP: 10+max(25,20) = 35 */
354 /* UDPLITE: 14+max(25,20) = 39 */
355 /* ICMP: 11+max(25, 18+25+max(19,14,24+3+n+10,3+n+10)) = 91+n */
356 /* ESP: 10+max(25)+15 = 50 */
357 /* AH: 9+max(25)+15 = 49 */
358 /* unknown: 10 */
359
360 /* (ICMP allows recursion one level deep) */
361 /* maxlen = IP + ICMP + IP + max(TCP,UDP,ICMP,unknown) */
362 /* maxlen = 230+ 91 + 230 + 252 = 803 */
363 }
364
365 static void dump_mac_header(struct sbuff *m,
366 const struct nf_loginfo *info,
367 const struct sk_buff *skb)
368 {
369 struct net_device *dev = skb->dev;
370 unsigned int logflags = 0;
371
372 if (info->type == NF_LOG_TYPE_LOG)
373 logflags = info->u.log.logflags;
374
375 if (!(logflags & IPT_LOG_MACDECODE))
376 goto fallback;
377
378 switch (dev->type) {
379 case ARPHRD_ETHER:
380 sb_add(m, "MACSRC=%pM MACDST=%pM MACPROTO=%04x ",
381 eth_hdr(skb)->h_source, eth_hdr(skb)->h_dest,
382 ntohs(eth_hdr(skb)->h_proto));
383 return;
384 default:
385 break;
386 }
387
388 fallback:
389 sb_add(m, "MAC=");
390 if (dev->hard_header_len &&
391 skb->mac_header != skb->network_header) {
392 const unsigned char *p = skb_mac_header(skb);
393 unsigned int i;
394
395 sb_add(m, "%02x", *p++);
396 for (i = 1; i < dev->hard_header_len; i++, p++)
397 sb_add(m, ":%02x", *p);
398 }
399 sb_add(m, " ");
400 }
401
402 static struct nf_loginfo default_loginfo = {
403 .type = NF_LOG_TYPE_LOG,
404 .u = {
405 .log = {
406 .level = 5,
407 .logflags = NF_LOG_MASK,
408 },
409 },
410 };
411
412 static void
413 ipt_log_packet(unsigned int pf,
414 unsigned int hooknum,
415 const struct sk_buff *skb,
416 const struct net_device *in,
417 const struct net_device *out,
418 const struct nf_loginfo *loginfo,
419 const char *prefix)
420 {
421 struct sbuff *m = sb_open();
422
423 if (!loginfo)
424 loginfo = &default_loginfo;
425
426 sb_add(m, "<%d>%sIN=%s OUT=%s ", loginfo->u.log.level,
427 prefix,
428 in ? in->name : "",
429 out ? out->name : "");
430 #ifdef CONFIG_BRIDGE_NETFILTER
431 if (skb->nf_bridge) {
432 struct net_device *physindev = skb->nf_bridge->physindev;
433 struct net_device *physoutdev = skb->nf_bridge->physoutdev;
434
435 if (physindev && in != physindev)
436 sb_add(m, "PHYSIN=%s ", physindev->name);
437 if (physoutdev && out != physoutdev)
438 sb_add(m, "PHYSOUT=%s ", physoutdev->name);
439 }
440 #endif
441
442 /* MAC logging for input path only. */
443 if (in && !out)
444 dump_mac_header(m, loginfo, skb);
445
446 dump_packet(m, loginfo, skb, 0);
447
448 sb_close(m);
449 }
450
451 static unsigned int
452 ipt_log_target(struct sk_buff *skb,
453 const struct net_device *in,
454 const struct net_device *out,
455 unsigned int hooknum,
456 const struct xt_target *target,
457 const void *targinfo)
458 {
459 const struct ipt_log_info *loginfo = targinfo;
460 struct nf_loginfo li;
461
462 li.type = NF_LOG_TYPE_LOG;
463 li.u.log.level = loginfo->level;
464 li.u.log.logflags = loginfo->logflags;
465
466 ipt_log_packet(PF_INET, hooknum, skb, in, out, &li,
467 loginfo->prefix);
468 return XT_CONTINUE;
469 }
470
471 static int ipt_log_checkentry(const char *tablename,
472 const void *e,
473 const struct xt_target *target,
474 void *targinfo,
475 unsigned int hook_mask)
476 {
477 const struct ipt_log_info *loginfo = targinfo;
478
479 if (loginfo->level >= 8) {
480 DEBUGP("LOG: level %u >= 8\n", loginfo->level);
481 return 0;
482 }
483 if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
484 DEBUGP("LOG: prefix term %i\n",
485 loginfo->prefix[sizeof(loginfo->prefix)-1]);
486 return 0;
487 }
488 return 1;
489 }
490
491 static struct xt_target ipt_log_reg = {
492 .name = "LOG",
493 .family = AF_INET,
494 .target = ipt_log_target,
495 .targetsize = sizeof(struct ipt_log_info),
496 .checkentry = ipt_log_checkentry,
497 .me = THIS_MODULE,
498 };
499
500 static struct nf_logger ipt_log_logger ={
501 .name = "ipt_LOG",
502 .logfn = &ipt_log_packet,
503 .me = THIS_MODULE,
504 };
505
506 static int __init ipt_log_init(void)
507 {
508 int ret;
509
510 ret = xt_register_target(&ipt_log_reg);
511 if (ret < 0)
512 return ret;
513 nf_log_register(PF_INET, &ipt_log_logger);
514 return 0;
515 }
516
517 static void __exit ipt_log_fini(void)
518 {
519 nf_log_unregister(&ipt_log_logger);
520 xt_unregister_target(&ipt_log_reg);
521 }
522
523 module_init(ipt_log_init);
524 module_exit(ipt_log_fini);
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