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Commit | Line | Data |
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1da177e4 LT |
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/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> | |
6709dbbb | 23 | #include <linux/netfilter/x_tables.h> |
1da177e4 LT |
24 | #include <linux/netfilter_ipv4/ipt_LOG.h> |
25 | ||
26 | MODULE_LICENSE("GPL"); | |
27 | MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); | |
28 | MODULE_DESCRIPTION("iptables syslog logging module"); | |
29 | ||
1da177e4 LT |
30 | #if 0 |
31 | #define DEBUGP printk | |
32 | #else | |
33 | #define DEBUGP(format, args...) | |
34 | #endif | |
35 | ||
36 | /* Use lock to serialize, so printks don't overlap */ | |
37 | static DEFINE_SPINLOCK(log_lock); | |
38 | ||
39 | /* One level of recursion won't kill us */ | |
608c8e4f | 40 | static void dump_packet(const struct nf_loginfo *info, |
1da177e4 LT |
41 | const struct sk_buff *skb, |
42 | unsigned int iphoff) | |
43 | { | |
44 | struct iphdr _iph, *ih; | |
608c8e4f HW |
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; | |
1da177e4 LT |
51 | |
52 | ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph); | |
53 | if (ih == NULL) { | |
54 | printk("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 | printk("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 | printk("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 | printk("CE "); | |
72 | if (ntohs(ih->frag_off) & IP_DF) | |
73 | printk("DF "); | |
74 | if (ntohs(ih->frag_off) & IP_MF) | |
75 | printk("MF "); | |
76 | ||
77 | /* Max length: 11 "FRAG:65535 " */ | |
78 | if (ntohs(ih->frag_off) & IP_OFFSET) | |
79 | printk("FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET); | |
80 | ||
608c8e4f | 81 | if ((logflags & IPT_LOG_IPOPT) |
1da177e4 LT |
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 | printk("TRUNCATED"); | |
91 | return; | |
92 | } | |
93 | ||
94 | /* Max length: 127 "OPT (" 15*4*2chars ") " */ | |
95 | printk("OPT ("); | |
96 | for (i = 0; i < optsize; i++) | |
97 | printk("%02X", op[i]); | |
98 | printk(") "); | |
99 | } | |
100 | ||
101 | switch (ih->protocol) { | |
102 | case IPPROTO_TCP: { | |
103 | struct tcphdr _tcph, *th; | |
104 | ||
105 | /* Max length: 10 "PROTO=TCP " */ | |
106 | printk("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 | printk("INCOMPLETE [%u bytes] ", | |
116 | skb->len - iphoff - ih->ihl*4); | |
117 | break; | |
118 | } | |
119 | ||
120 | /* Max length: 20 "SPT=65535 DPT=65535 " */ | |
121 | printk("SPT=%u DPT=%u ", | |
122 | ntohs(th->source), ntohs(th->dest)); | |
123 | /* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */ | |
608c8e4f | 124 | if (logflags & IPT_LOG_TCPSEQ) |
1da177e4 LT |
125 | printk("SEQ=%u ACK=%u ", |
126 | ntohl(th->seq), ntohl(th->ack_seq)); | |
127 | /* Max length: 13 "WINDOW=65535 " */ | |
128 | printk("WINDOW=%u ", ntohs(th->window)); | |
129 | /* Max length: 9 "RES=0x3F " */ | |
130 | printk("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 | printk("CWR "); | |
134 | if (th->ece) | |
135 | printk("ECE "); | |
136 | if (th->urg) | |
137 | printk("URG "); | |
138 | if (th->ack) | |
139 | printk("ACK "); | |
140 | if (th->psh) | |
141 | printk("PSH "); | |
142 | if (th->rst) | |
143 | printk("RST "); | |
144 | if (th->syn) | |
145 | printk("SYN "); | |
146 | if (th->fin) | |
147 | printk("FIN "); | |
148 | /* Max length: 11 "URGP=65535 " */ | |
149 | printk("URGP=%u ", ntohs(th->urg_ptr)); | |
150 | ||
608c8e4f | 151 | if ((logflags & IPT_LOG_TCPOPT) |
1da177e4 LT |
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 | printk("TRUNCATED"); | |
163 | return; | |
164 | } | |
165 | ||
166 | /* Max length: 127 "OPT (" 15*4*2chars ") " */ | |
167 | printk("OPT ("); | |
168 | for (i = 0; i < optsize; i++) | |
169 | printk("%02X", op[i]); | |
170 | printk(") "); | |
171 | } | |
172 | break; | |
173 | } | |
ba4e58ec GR |
174 | case IPPROTO_UDP: |
175 | case IPPROTO_UDPLITE: { | |
1da177e4 LT |
176 | struct udphdr _udph, *uh; |
177 | ||
ba4e58ec GR |
178 | if (ih->protocol == IPPROTO_UDP) |
179 | /* Max length: 10 "PROTO=UDP " */ | |
180 | printk("PROTO=UDP " ); | |
181 | else /* Max length: 14 "PROTO=UDPLITE " */ | |
182 | printk("PROTO=UDPLITE "); | |
1da177e4 LT |
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 | printk("INCOMPLETE [%u bytes] ", | |
192 | skb->len - iphoff - ih->ihl*4); | |
193 | break; | |
194 | } | |
195 | ||
196 | /* Max length: 20 "SPT=65535 DPT=65535 " */ | |
197 | printk("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; | |
9b5b5cff | 204 | static const size_t required_len[NR_ICMP_TYPES+1] |
1da177e4 LT |
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 | printk("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 | printk("INCOMPLETE [%u bytes] ", | |
233 | skb->len - iphoff - ih->ihl*4); | |
234 | break; | |
235 | } | |
236 | ||
237 | /* Max length: 18 "TYPE=255 CODE=255 " */ | |
238 | printk("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 | 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 | /* Max length: 19 "ID=65535 SEQ=65535 " */ | |
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 | /* Max length: 14 "PARAMETER=255 " */ | |
260 | printk("PARAMETER=%u ", | |
261 | ntohl(ich->un.gateway) >> 24); | |
262 | break; | |
263 | case ICMP_REDIRECT: | |
264 | /* Max length: 24 "GATEWAY=255.255.255.255 " */ | |
265 | printk("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 | printk("["); | |
274 | dump_packet(info, skb, | |
275 | iphoff + ih->ihl*4+sizeof(_icmph)); | |
276 | printk("] "); | |
277 | } | |
278 | ||
279 | /* Max length: 10 "MTU=65535 " */ | |
280 | if (ich->type == ICMP_DEST_UNREACH | |
281 | && ich->code == ICMP_FRAG_NEEDED) | |
282 | printk("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; | |
e905a9ed | 292 | |
1da177e4 LT |
293 | /* Max length: 9 "PROTO=AH " */ |
294 | printk("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 | printk("INCOMPLETE [%u bytes] ", | |
301 | skb->len - iphoff - ih->ihl*4); | |
302 | break; | |
303 | } | |
304 | ||
305 | /* Length: 15 "SPI=0xF1234567 " */ | |
306 | printk("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 | printk("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 | printk("INCOMPLETE [%u bytes] ", | |
323 | skb->len - iphoff - ih->ihl*4); | |
324 | break; | |
325 | } | |
326 | ||
327 | /* Length: 15 "SPI=0xF1234567 " */ | |
328 | printk("SPI=0x%x ", ntohl(eh->spi)); | |
329 | break; | |
330 | } | |
331 | /* Max length: 10 "PROTO 255 " */ | |
332 | default: | |
333 | printk("PROTO=%u ", ih->protocol); | |
334 | } | |
335 | ||
336 | /* Max length: 15 "UID=4294967295 " */ | |
e905a9ed | 337 | if ((logflags & IPT_LOG_UID) && !iphoff && skb->sk) { |
1da177e4 LT |
338 | read_lock_bh(&skb->sk->sk_callback_lock); |
339 | if (skb->sk->sk_socket && skb->sk->sk_socket->file) | |
e905a9ed | 340 | printk("UID=%u ", skb->sk->sk_socket->file->f_uid); |
1da177e4 LT |
341 | read_unlock_bh(&skb->sk->sk_callback_lock); |
342 | } | |
343 | ||
344 | /* Proto Max log string length */ | |
345 | /* IP: 40+46+6+11+127 = 230 */ | |
346 | /* TCP: 10+max(25,20+30+13+9+32+11+127) = 252 */ | |
347 | /* UDP: 10+max(25,20) = 35 */ | |
ba4e58ec | 348 | /* UDPLITE: 14+max(25,20) = 39 */ |
1da177e4 LT |
349 | /* ICMP: 11+max(25, 18+25+max(19,14,24+3+n+10,3+n+10)) = 91+n */ |
350 | /* ESP: 10+max(25)+15 = 50 */ | |
351 | /* AH: 9+max(25)+15 = 49 */ | |
352 | /* unknown: 10 */ | |
353 | ||
354 | /* (ICMP allows recursion one level deep) */ | |
355 | /* maxlen = IP + ICMP + IP + max(TCP,UDP,ICMP,unknown) */ | |
356 | /* maxlen = 230+ 91 + 230 + 252 = 803 */ | |
357 | } | |
358 | ||
d127e94a | 359 | static struct nf_loginfo default_loginfo = { |
608c8e4f HW |
360 | .type = NF_LOG_TYPE_LOG, |
361 | .u = { | |
362 | .log = { | |
363 | .level = 0, | |
364 | .logflags = NF_LOG_MASK, | |
365 | }, | |
366 | }, | |
367 | }; | |
368 | ||
1da177e4 | 369 | static void |
608c8e4f HW |
370 | ipt_log_packet(unsigned int pf, |
371 | unsigned int hooknum, | |
1da177e4 LT |
372 | const struct sk_buff *skb, |
373 | const struct net_device *in, | |
374 | const struct net_device *out, | |
608c8e4f | 375 | const struct nf_loginfo *loginfo, |
1da177e4 LT |
376 | const char *prefix) |
377 | { | |
608c8e4f HW |
378 | if (!loginfo) |
379 | loginfo = &default_loginfo; | |
380 | ||
1da177e4 | 381 | spin_lock_bh(&log_lock); |
608c8e4f HW |
382 | printk("<%d>%sIN=%s OUT=%s ", loginfo->u.log.level, |
383 | prefix, | |
1da177e4 LT |
384 | in ? in->name : "", |
385 | out ? out->name : ""); | |
386 | #ifdef CONFIG_BRIDGE_NETFILTER | |
387 | if (skb->nf_bridge) { | |
388 | struct net_device *physindev = skb->nf_bridge->physindev; | |
389 | struct net_device *physoutdev = skb->nf_bridge->physoutdev; | |
390 | ||
391 | if (physindev && in != physindev) | |
392 | printk("PHYSIN=%s ", physindev->name); | |
393 | if (physoutdev && out != physoutdev) | |
394 | printk("PHYSOUT=%s ", physoutdev->name); | |
395 | } | |
396 | #endif | |
397 | ||
398 | if (in && !out) { | |
399 | /* MAC logging for input chain only. */ | |
400 | printk("MAC="); | |
401 | if (skb->dev && skb->dev->hard_header_len | |
b0e380b1 | 402 | && skb->mac_header != skb->network_header) { |
1da177e4 | 403 | int i; |
98e399f8 | 404 | const unsigned char *p = skb_mac_header(skb); |
1da177e4 LT |
405 | for (i = 0; i < skb->dev->hard_header_len; i++,p++) |
406 | printk("%02x%c", *p, | |
407 | i==skb->dev->hard_header_len - 1 | |
408 | ? ' ':':'); | |
409 | } else | |
410 | printk(" "); | |
411 | } | |
412 | ||
413 | dump_packet(loginfo, skb, 0); | |
414 | printk("\n"); | |
415 | spin_unlock_bh(&log_lock); | |
416 | } | |
417 | ||
418 | static unsigned int | |
419 | ipt_log_target(struct sk_buff **pskb, | |
420 | const struct net_device *in, | |
421 | const struct net_device *out, | |
422 | unsigned int hooknum, | |
c4986734 | 423 | const struct xt_target *target, |
fe1cb108 | 424 | const void *targinfo) |
1da177e4 LT |
425 | { |
426 | const struct ipt_log_info *loginfo = targinfo; | |
608c8e4f | 427 | struct nf_loginfo li; |
1da177e4 | 428 | |
608c8e4f HW |
429 | li.type = NF_LOG_TYPE_LOG; |
430 | li.u.log.level = loginfo->level; | |
431 | li.u.log.logflags = loginfo->logflags; | |
1da177e4 | 432 | |
baf7b1e1 | 433 | ipt_log_packet(PF_INET, hooknum, *pskb, in, out, &li, |
e905a9ed | 434 | loginfo->prefix); |
6709dbbb | 435 | return XT_CONTINUE; |
1da177e4 LT |
436 | } |
437 | ||
438 | static int ipt_log_checkentry(const char *tablename, | |
2e4e6a17 | 439 | const void *e, |
c4986734 | 440 | const struct xt_target *target, |
1da177e4 | 441 | void *targinfo, |
1da177e4 LT |
442 | unsigned int hook_mask) |
443 | { | |
444 | const struct ipt_log_info *loginfo = targinfo; | |
445 | ||
1da177e4 LT |
446 | if (loginfo->level >= 8) { |
447 | DEBUGP("LOG: level %u >= 8\n", loginfo->level); | |
448 | return 0; | |
449 | } | |
1da177e4 LT |
450 | if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') { |
451 | DEBUGP("LOG: prefix term %i\n", | |
452 | loginfo->prefix[sizeof(loginfo->prefix)-1]); | |
453 | return 0; | |
454 | } | |
1da177e4 LT |
455 | return 1; |
456 | } | |
457 | ||
6709dbbb | 458 | static struct xt_target ipt_log_reg = { |
1da177e4 | 459 | .name = "LOG", |
6709dbbb | 460 | .family = AF_INET, |
1da177e4 | 461 | .target = ipt_log_target, |
1d5cd909 | 462 | .targetsize = sizeof(struct ipt_log_info), |
1da177e4 LT |
463 | .checkentry = ipt_log_checkentry, |
464 | .me = THIS_MODULE, | |
465 | }; | |
466 | ||
608c8e4f HW |
467 | static struct nf_logger ipt_log_logger ={ |
468 | .name = "ipt_LOG", | |
469 | .logfn = &ipt_log_packet, | |
470 | .me = THIS_MODULE, | |
471 | }; | |
472 | ||
65b4b4e8 | 473 | static int __init ipt_log_init(void) |
1da177e4 | 474 | { |
e1fd0586 JE |
475 | int ret; |
476 | ||
6709dbbb | 477 | ret = xt_register_target(&ipt_log_reg); |
e1fd0586 JE |
478 | if (ret < 0) |
479 | return ret; | |
608c8e4f HW |
480 | if (nf_log_register(PF_INET, &ipt_log_logger) < 0) { |
481 | printk(KERN_WARNING "ipt_LOG: not logging via system console " | |
482 | "since somebody else already registered for PF_INET\n"); | |
483 | /* we cannot make module load fail here, since otherwise | |
484 | * iptables userspace would abort */ | |
485 | } | |
e905a9ed | 486 | |
1da177e4 LT |
487 | return 0; |
488 | } | |
489 | ||
65b4b4e8 | 490 | static void __exit ipt_log_fini(void) |
1da177e4 | 491 | { |
e92ad99c | 492 | nf_log_unregister(&ipt_log_logger); |
6709dbbb | 493 | xt_unregister_target(&ipt_log_reg); |
1da177e4 LT |
494 | } |
495 | ||
65b4b4e8 AM |
496 | module_init(ipt_log_init); |
497 | module_exit(ipt_log_fini); |