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[NETFILTER]: add some consts, remove some casts
[deliverable/linux.git] / net / ipv4 / netfilter / ipt_LOG.c
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>
23 #include <linux/netfilter/x_tables.h>
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
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 */
40 static void dump_packet(const struct nf_loginfo *info,
41 const struct sk_buff *skb,
42 unsigned int iphoff)
43 {
44 struct iphdr _iph;
45 const struct iphdr *ih;
46 unsigned int logflags;
47
48 if (info->type == NF_LOG_TYPE_LOG)
49 logflags = info->u.log.logflags;
50 else
51 logflags = NF_LOG_MASK;
52
53 ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph);
54 if (ih == NULL) {
55 printk("TRUNCATED");
56 return;
57 }
58
59 /* Important fields:
60 * TOS, len, DF/MF, fragment offset, TTL, src, dst, options. */
61 /* Max length: 40 "SRC=255.255.255.255 DST=255.255.255.255 " */
62 printk("SRC=%u.%u.%u.%u DST=%u.%u.%u.%u ",
63 NIPQUAD(ih->saddr), NIPQUAD(ih->daddr));
64
65 /* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */
66 printk("LEN=%u TOS=0x%02X PREC=0x%02X TTL=%u ID=%u ",
67 ntohs(ih->tot_len), ih->tos & IPTOS_TOS_MASK,
68 ih->tos & IPTOS_PREC_MASK, ih->ttl, ntohs(ih->id));
69
70 /* Max length: 6 "CE DF MF " */
71 if (ntohs(ih->frag_off) & IP_CE)
72 printk("CE ");
73 if (ntohs(ih->frag_off) & IP_DF)
74 printk("DF ");
75 if (ntohs(ih->frag_off) & IP_MF)
76 printk("MF ");
77
78 /* Max length: 11 "FRAG:65535 " */
79 if (ntohs(ih->frag_off) & IP_OFFSET)
80 printk("FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET);
81
82 if ((logflags & IPT_LOG_IPOPT)
83 && ih->ihl * 4 > sizeof(struct iphdr)) {
84 unsigned char _opt[4 * 15 - sizeof(struct iphdr)], *op;
85 unsigned int i, optsize;
86
87 optsize = ih->ihl * 4 - sizeof(struct iphdr);
88 op = skb_header_pointer(skb, iphoff+sizeof(_iph),
89 optsize, _opt);
90 if (op == NULL) {
91 printk("TRUNCATED");
92 return;
93 }
94
95 /* Max length: 127 "OPT (" 15*4*2chars ") " */
96 printk("OPT (");
97 for (i = 0; i < optsize; i++)
98 printk("%02X", op[i]);
99 printk(") ");
100 }
101
102 switch (ih->protocol) {
103 case IPPROTO_TCP: {
104 struct tcphdr _tcph;
105 const struct tcphdr *th;
106
107 /* Max length: 10 "PROTO=TCP " */
108 printk("PROTO=TCP ");
109
110 if (ntohs(ih->frag_off) & IP_OFFSET)
111 break;
112
113 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
114 th = skb_header_pointer(skb, iphoff + ih->ihl * 4,
115 sizeof(_tcph), &_tcph);
116 if (th == NULL) {
117 printk("INCOMPLETE [%u bytes] ",
118 skb->len - iphoff - ih->ihl*4);
119 break;
120 }
121
122 /* Max length: 20 "SPT=65535 DPT=65535 " */
123 printk("SPT=%u DPT=%u ",
124 ntohs(th->source), ntohs(th->dest));
125 /* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
126 if (logflags & IPT_LOG_TCPSEQ)
127 printk("SEQ=%u ACK=%u ",
128 ntohl(th->seq), ntohl(th->ack_seq));
129 /* Max length: 13 "WINDOW=65535 " */
130 printk("WINDOW=%u ", ntohs(th->window));
131 /* Max length: 9 "RES=0x3F " */
132 printk("RES=0x%02x ", (u8)(ntohl(tcp_flag_word(th) & TCP_RESERVED_BITS) >> 22));
133 /* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
134 if (th->cwr)
135 printk("CWR ");
136 if (th->ece)
137 printk("ECE ");
138 if (th->urg)
139 printk("URG ");
140 if (th->ack)
141 printk("ACK ");
142 if (th->psh)
143 printk("PSH ");
144 if (th->rst)
145 printk("RST ");
146 if (th->syn)
147 printk("SYN ");
148 if (th->fin)
149 printk("FIN ");
150 /* Max length: 11 "URGP=65535 " */
151 printk("URGP=%u ", ntohs(th->urg_ptr));
152
153 if ((logflags & IPT_LOG_TCPOPT)
154 && th->doff * 4 > sizeof(struct tcphdr)) {
155 unsigned char _opt[4 * 15 - sizeof(struct tcphdr)];
156 const unsigned char *op;
157 unsigned int i, optsize;
158
159 optsize = th->doff * 4 - sizeof(struct tcphdr);
160 op = skb_header_pointer(skb,
161 iphoff+ih->ihl*4+sizeof(_tcph),
162 optsize, _opt);
163 if (op == NULL) {
164 printk("TRUNCATED");
165 return;
166 }
167
168 /* Max length: 127 "OPT (" 15*4*2chars ") " */
169 printk("OPT (");
170 for (i = 0; i < optsize; i++)
171 printk("%02X", op[i]);
172 printk(") ");
173 }
174 break;
175 }
176 case IPPROTO_UDP:
177 case IPPROTO_UDPLITE: {
178 struct udphdr _udph;
179 const struct udphdr *uh;
180
181 if (ih->protocol == IPPROTO_UDP)
182 /* Max length: 10 "PROTO=UDP " */
183 printk("PROTO=UDP " );
184 else /* Max length: 14 "PROTO=UDPLITE " */
185 printk("PROTO=UDPLITE ");
186
187 if (ntohs(ih->frag_off) & IP_OFFSET)
188 break;
189
190 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
191 uh = skb_header_pointer(skb, iphoff+ih->ihl*4,
192 sizeof(_udph), &_udph);
193 if (uh == NULL) {
194 printk("INCOMPLETE [%u bytes] ",
195 skb->len - iphoff - ih->ihl*4);
196 break;
197 }
198
199 /* Max length: 20 "SPT=65535 DPT=65535 " */
200 printk("SPT=%u DPT=%u LEN=%u ",
201 ntohs(uh->source), ntohs(uh->dest),
202 ntohs(uh->len));
203 break;
204 }
205 case IPPROTO_ICMP: {
206 struct icmphdr _icmph;
207 const struct icmphdr *ich;
208 static const size_t required_len[NR_ICMP_TYPES+1]
209 = { [ICMP_ECHOREPLY] = 4,
210 [ICMP_DEST_UNREACH]
211 = 8 + sizeof(struct iphdr),
212 [ICMP_SOURCE_QUENCH]
213 = 8 + sizeof(struct iphdr),
214 [ICMP_REDIRECT]
215 = 8 + sizeof(struct iphdr),
216 [ICMP_ECHO] = 4,
217 [ICMP_TIME_EXCEEDED]
218 = 8 + sizeof(struct iphdr),
219 [ICMP_PARAMETERPROB]
220 = 8 + sizeof(struct iphdr),
221 [ICMP_TIMESTAMP] = 20,
222 [ICMP_TIMESTAMPREPLY] = 20,
223 [ICMP_ADDRESS] = 12,
224 [ICMP_ADDRESSREPLY] = 12 };
225
226 /* Max length: 11 "PROTO=ICMP " */
227 printk("PROTO=ICMP ");
228
229 if (ntohs(ih->frag_off) & IP_OFFSET)
230 break;
231
232 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
233 ich = skb_header_pointer(skb, iphoff + ih->ihl * 4,
234 sizeof(_icmph), &_icmph);
235 if (ich == NULL) {
236 printk("INCOMPLETE [%u bytes] ",
237 skb->len - iphoff - ih->ihl*4);
238 break;
239 }
240
241 /* Max length: 18 "TYPE=255 CODE=255 " */
242 printk("TYPE=%u CODE=%u ", ich->type, ich->code);
243
244 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
245 if (ich->type <= NR_ICMP_TYPES
246 && required_len[ich->type]
247 && skb->len-iphoff-ih->ihl*4 < required_len[ich->type]) {
248 printk("INCOMPLETE [%u bytes] ",
249 skb->len - iphoff - ih->ihl*4);
250 break;
251 }
252
253 switch (ich->type) {
254 case ICMP_ECHOREPLY:
255 case ICMP_ECHO:
256 /* Max length: 19 "ID=65535 SEQ=65535 " */
257 printk("ID=%u SEQ=%u ",
258 ntohs(ich->un.echo.id),
259 ntohs(ich->un.echo.sequence));
260 break;
261
262 case ICMP_PARAMETERPROB:
263 /* Max length: 14 "PARAMETER=255 " */
264 printk("PARAMETER=%u ",
265 ntohl(ich->un.gateway) >> 24);
266 break;
267 case ICMP_REDIRECT:
268 /* Max length: 24 "GATEWAY=255.255.255.255 " */
269 printk("GATEWAY=%u.%u.%u.%u ",
270 NIPQUAD(ich->un.gateway));
271 /* Fall through */
272 case ICMP_DEST_UNREACH:
273 case ICMP_SOURCE_QUENCH:
274 case ICMP_TIME_EXCEEDED:
275 /* Max length: 3+maxlen */
276 if (!iphoff) { /* Only recurse once. */
277 printk("[");
278 dump_packet(info, skb,
279 iphoff + ih->ihl*4+sizeof(_icmph));
280 printk("] ");
281 }
282
283 /* Max length: 10 "MTU=65535 " */
284 if (ich->type == ICMP_DEST_UNREACH
285 && ich->code == ICMP_FRAG_NEEDED)
286 printk("MTU=%u ", ntohs(ich->un.frag.mtu));
287 }
288 break;
289 }
290 /* Max Length */
291 case IPPROTO_AH: {
292 struct ip_auth_hdr _ahdr;
293 const struct ip_auth_hdr *ah;
294
295 if (ntohs(ih->frag_off) & IP_OFFSET)
296 break;
297
298 /* Max length: 9 "PROTO=AH " */
299 printk("PROTO=AH ");
300
301 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
302 ah = skb_header_pointer(skb, iphoff+ih->ihl*4,
303 sizeof(_ahdr), &_ahdr);
304 if (ah == NULL) {
305 printk("INCOMPLETE [%u bytes] ",
306 skb->len - iphoff - ih->ihl*4);
307 break;
308 }
309
310 /* Length: 15 "SPI=0xF1234567 " */
311 printk("SPI=0x%x ", ntohl(ah->spi));
312 break;
313 }
314 case IPPROTO_ESP: {
315 struct ip_esp_hdr _esph;
316 const struct ip_esp_hdr *eh;
317
318 /* Max length: 10 "PROTO=ESP " */
319 printk("PROTO=ESP ");
320
321 if (ntohs(ih->frag_off) & IP_OFFSET)
322 break;
323
324 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
325 eh = skb_header_pointer(skb, iphoff+ih->ihl*4,
326 sizeof(_esph), &_esph);
327 if (eh == NULL) {
328 printk("INCOMPLETE [%u bytes] ",
329 skb->len - iphoff - ih->ihl*4);
330 break;
331 }
332
333 /* Length: 15 "SPI=0xF1234567 " */
334 printk("SPI=0x%x ", ntohl(eh->spi));
335 break;
336 }
337 /* Max length: 10 "PROTO 255 " */
338 default:
339 printk("PROTO=%u ", ih->protocol);
340 }
341
342 /* Max length: 15 "UID=4294967295 " */
343 if ((logflags & IPT_LOG_UID) && !iphoff && skb->sk) {
344 read_lock_bh(&skb->sk->sk_callback_lock);
345 if (skb->sk->sk_socket && skb->sk->sk_socket->file)
346 printk("UID=%u ", skb->sk->sk_socket->file->f_uid);
347 read_unlock_bh(&skb->sk->sk_callback_lock);
348 }
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 struct nf_loginfo default_loginfo = {
366 .type = NF_LOG_TYPE_LOG,
367 .u = {
368 .log = {
369 .level = 0,
370 .logflags = NF_LOG_MASK,
371 },
372 },
373 };
374
375 static void
376 ipt_log_packet(unsigned int pf,
377 unsigned int hooknum,
378 const struct sk_buff *skb,
379 const struct net_device *in,
380 const struct net_device *out,
381 const struct nf_loginfo *loginfo,
382 const char *prefix)
383 {
384 if (!loginfo)
385 loginfo = &default_loginfo;
386
387 spin_lock_bh(&log_lock);
388 printk("<%d>%sIN=%s OUT=%s ", loginfo->u.log.level,
389 prefix,
390 in ? in->name : "",
391 out ? out->name : "");
392 #ifdef CONFIG_BRIDGE_NETFILTER
393 if (skb->nf_bridge) {
394 const struct net_device *physindev;
395 const struct net_device *physoutdev;
396
397 physindev = skb->nf_bridge->physindev;
398 if (physindev && in != physindev)
399 printk("PHYSIN=%s ", physindev->name);
400 physoutdev = skb->nf_bridge->physoutdev;
401 if (physoutdev && out != physoutdev)
402 printk("PHYSOUT=%s ", physoutdev->name);
403 }
404 #endif
405
406 if (in && !out) {
407 /* MAC logging for input chain only. */
408 printk("MAC=");
409 if (skb->dev && skb->dev->hard_header_len
410 && skb->mac_header != skb->network_header) {
411 int i;
412 const unsigned char *p = skb_mac_header(skb);
413 for (i = 0; i < skb->dev->hard_header_len; i++,p++)
414 printk("%02x%c", *p,
415 i==skb->dev->hard_header_len - 1
416 ? ' ':':');
417 } else
418 printk(" ");
419 }
420
421 dump_packet(loginfo, skb, 0);
422 printk("\n");
423 spin_unlock_bh(&log_lock);
424 }
425
426 static unsigned int
427 ipt_log_target(struct sk_buff **pskb,
428 const struct net_device *in,
429 const struct net_device *out,
430 unsigned int hooknum,
431 const struct xt_target *target,
432 const void *targinfo)
433 {
434 const struct ipt_log_info *loginfo = targinfo;
435 struct nf_loginfo li;
436
437 li.type = NF_LOG_TYPE_LOG;
438 li.u.log.level = loginfo->level;
439 li.u.log.logflags = loginfo->logflags;
440
441 ipt_log_packet(PF_INET, hooknum, *pskb, in, out, &li,
442 loginfo->prefix);
443 return XT_CONTINUE;
444 }
445
446 static bool ipt_log_checkentry(const char *tablename,
447 const void *e,
448 const struct xt_target *target,
449 void *targinfo,
450 unsigned int hook_mask)
451 {
452 const struct ipt_log_info *loginfo = targinfo;
453
454 if (loginfo->level >= 8) {
455 DEBUGP("LOG: level %u >= 8\n", loginfo->level);
456 return false;
457 }
458 if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
459 DEBUGP("LOG: prefix term %i\n",
460 loginfo->prefix[sizeof(loginfo->prefix)-1]);
461 return false;
462 }
463 return true;
464 }
465
466 static struct xt_target ipt_log_reg = {
467 .name = "LOG",
468 .family = AF_INET,
469 .target = ipt_log_target,
470 .targetsize = sizeof(struct ipt_log_info),
471 .checkentry = ipt_log_checkentry,
472 .me = THIS_MODULE,
473 };
474
475 static struct nf_logger ipt_log_logger ={
476 .name = "ipt_LOG",
477 .logfn = &ipt_log_packet,
478 .me = THIS_MODULE,
479 };
480
481 static int __init ipt_log_init(void)
482 {
483 int ret;
484
485 ret = xt_register_target(&ipt_log_reg);
486 if (ret < 0)
487 return ret;
488 ret = nf_log_register(PF_INET, &ipt_log_logger);
489 if (ret < 0 && ret != -EEXIST)
490 xt_unregister_target(&ipt_log_reg);
491 return ret;
492 }
493
494 static void __exit ipt_log_fini(void)
495 {
496 nf_log_unregister(&ipt_log_logger);
497 xt_unregister_target(&ipt_log_reg);
498 }
499
500 module_init(ipt_log_init);
501 module_exit(ipt_log_fini);
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