4b346e59bf2db64c024f9ccda2cb6f9ec61221e8
[linux-2.6.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 #include <net/netfilter/nf_log.h>
26
27 MODULE_LICENSE("GPL");
28 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
29 MODULE_DESCRIPTION("iptables syslog logging module");
30
31 /* Use lock to serialize, so printks don't overlap */
32 static DEFINE_SPINLOCK(log_lock);
33
34 /* One level of recursion won't kill us */
35 static 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         /* Important fields:
55          * TOS, len, DF/MF, fragment offset, TTL, src, dst, options. */
56         /* Max length: 40 "SRC=255.255.255.255 DST=255.255.255.255 " */
57         printk("SRC=%u.%u.%u.%u DST=%u.%u.%u.%u ",
58                NIPQUAD(ih->saddr), NIPQUAD(ih->daddr));
59
60         /* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */
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         /* Max length: 6 "CE DF MF " */
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         /* Max length: 11 "FRAG:65535 " */
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                 unsigned char _opt[4 * 15 - sizeof(struct iphdr)], *op;
80                 unsigned int i, optsize;
81
82                 optsize = ih->ihl * 4 - sizeof(struct iphdr);
83                 op = skb_header_pointer(skb, iphoff+sizeof(_iph),
84                                         optsize, _opt);
85                 if (op == NULL) {
86                         printk("TRUNCATED");
87                         return;
88                 }
89
90                 /* Max length: 127 "OPT (" 15*4*2chars ") " */
91                 printk("OPT (");
92                 for (i = 0; i < optsize; i++)
93                         printk("%02X", op[i]);
94                 printk(") ");
95         }
96
97         switch (ih->protocol) {
98         case IPPROTO_TCP: {
99                 struct tcphdr _tcph;
100                 const struct tcphdr *th;
101
102                 /* Max length: 10 "PROTO=TCP " */
103                 printk("PROTO=TCP ");
104
105                 if (ntohs(ih->frag_off) & IP_OFFSET)
106                         break;
107
108                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
109                 th = skb_header_pointer(skb, iphoff + ih->ihl * 4,
110                                         sizeof(_tcph), &_tcph);
111                 if (th == NULL) {
112                         printk("INCOMPLETE [%u bytes] ",
113                                skb->len - iphoff - ih->ihl*4);
114                         break;
115                 }
116
117                 /* Max length: 20 "SPT=65535 DPT=65535 " */
118                 printk("SPT=%u DPT=%u ",
119                        ntohs(th->source), ntohs(th->dest));
120                 /* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
121                 if (logflags & IPT_LOG_TCPSEQ)
122                         printk("SEQ=%u ACK=%u ",
123                                ntohl(th->seq), ntohl(th->ack_seq));
124                 /* Max length: 13 "WINDOW=65535 " */
125                 printk("WINDOW=%u ", ntohs(th->window));
126                 /* Max length: 9 "RES=0x3F " */
127                 printk("RES=0x%02x ", (u8)(ntohl(tcp_flag_word(th) & TCP_RESERVED_BITS) >> 22));
128                 /* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
129                 if (th->cwr)
130                         printk("CWR ");
131                 if (th->ece)
132                         printk("ECE ");
133                 if (th->urg)
134                         printk("URG ");
135                 if (th->ack)
136                         printk("ACK ");
137                 if (th->psh)
138                         printk("PSH ");
139                 if (th->rst)
140                         printk("RST ");
141                 if (th->syn)
142                         printk("SYN ");
143                 if (th->fin)
144                         printk("FIN ");
145                 /* Max length: 11 "URGP=65535 " */
146                 printk("URGP=%u ", ntohs(th->urg_ptr));
147
148                 if ((logflags & IPT_LOG_TCPOPT)
149                     && th->doff * 4 > sizeof(struct tcphdr)) {
150                         unsigned char _opt[4 * 15 - sizeof(struct tcphdr)];
151                         const unsigned char *op;
152                         unsigned int i, optsize;
153
154                         optsize = th->doff * 4 - sizeof(struct tcphdr);
155                         op = skb_header_pointer(skb,
156                                                 iphoff+ih->ihl*4+sizeof(_tcph),
157                                                 optsize, _opt);
158                         if (op == NULL) {
159                                 printk("TRUNCATED");
160                                 return;
161                         }
162
163                         /* Max length: 127 "OPT (" 15*4*2chars ") " */
164                         printk("OPT (");
165                         for (i = 0; i < optsize; i++)
166                                 printk("%02X", op[i]);
167                         printk(") ");
168                 }
169                 break;
170         }
171         case IPPROTO_UDP:
172         case IPPROTO_UDPLITE: {
173                 struct udphdr _udph;
174                 const struct udphdr *uh;
175
176                 if (ih->protocol == IPPROTO_UDP)
177                         /* Max length: 10 "PROTO=UDP "     */
178                         printk("PROTO=UDP " );
179                 else    /* Max length: 14 "PROTO=UDPLITE " */
180                         printk("PROTO=UDPLITE ");
181
182                 if (ntohs(ih->frag_off) & IP_OFFSET)
183                         break;
184
185                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
186                 uh = skb_header_pointer(skb, iphoff+ih->ihl*4,
187                                         sizeof(_udph), &_udph);
188                 if (uh == NULL) {
189                         printk("INCOMPLETE [%u bytes] ",
190                                skb->len - iphoff - ih->ihl*4);
191                         break;
192                 }
193
194                 /* Max length: 20 "SPT=65535 DPT=65535 " */
195                 printk("SPT=%u DPT=%u LEN=%u ",
196                        ntohs(uh->source), ntohs(uh->dest),
197                        ntohs(uh->len));
198                 break;
199         }
200         case IPPROTO_ICMP: {
201                 struct icmphdr _icmph;
202                 const struct icmphdr *ich;
203                 static const size_t required_len[NR_ICMP_TYPES+1]
204                         = { [ICMP_ECHOREPLY] = 4,
205                             [ICMP_DEST_UNREACH]
206                             = 8 + sizeof(struct iphdr),
207                             [ICMP_SOURCE_QUENCH]
208                             = 8 + sizeof(struct iphdr),
209                             [ICMP_REDIRECT]
210                             = 8 + sizeof(struct iphdr),
211                             [ICMP_ECHO] = 4,
212                             [ICMP_TIME_EXCEEDED]
213                             = 8 + sizeof(struct iphdr),
214                             [ICMP_PARAMETERPROB]
215                             = 8 + sizeof(struct iphdr),
216                             [ICMP_TIMESTAMP] = 20,
217                             [ICMP_TIMESTAMPREPLY] = 20,
218                             [ICMP_ADDRESS] = 12,
219                             [ICMP_ADDRESSREPLY] = 12 };
220
221                 /* Max length: 11 "PROTO=ICMP " */
222                 printk("PROTO=ICMP ");
223
224                 if (ntohs(ih->frag_off) & IP_OFFSET)
225                         break;
226
227                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
228                 ich = skb_header_pointer(skb, iphoff + ih->ihl * 4,
229                                          sizeof(_icmph), &_icmph);
230                 if (ich == NULL) {
231                         printk("INCOMPLETE [%u bytes] ",
232                                skb->len - iphoff - ih->ihl*4);
233                         break;
234                 }
235
236                 /* Max length: 18 "TYPE=255 CODE=255 " */
237                 printk("TYPE=%u CODE=%u ", ich->type, ich->code);
238
239                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
240                 if (ich->type <= NR_ICMP_TYPES
241                     && required_len[ich->type]
242                     && skb->len-iphoff-ih->ihl*4 < required_len[ich->type]) {
243                         printk("INCOMPLETE [%u bytes] ",
244                                skb->len - iphoff - ih->ihl*4);
245                         break;
246                 }
247
248                 switch (ich->type) {
249                 case ICMP_ECHOREPLY:
250                 case ICMP_ECHO:
251                         /* Max length: 19 "ID=65535 SEQ=65535 " */
252                         printk("ID=%u SEQ=%u ",
253                                ntohs(ich->un.echo.id),
254                                ntohs(ich->un.echo.sequence));
255                         break;
256
257                 case ICMP_PARAMETERPROB:
258                         /* Max length: 14 "PARAMETER=255 " */
259                         printk("PARAMETER=%u ",
260                                ntohl(ich->un.gateway) >> 24);
261                         break;
262                 case ICMP_REDIRECT:
263                         /* Max length: 24 "GATEWAY=255.255.255.255 " */
264                         printk("GATEWAY=%u.%u.%u.%u ",
265                                NIPQUAD(ich->un.gateway));
266                         /* Fall through */
267                 case ICMP_DEST_UNREACH:
268                 case ICMP_SOURCE_QUENCH:
269                 case ICMP_TIME_EXCEEDED:
270                         /* Max length: 3+maxlen */
271                         if (!iphoff) { /* Only recurse once. */
272                                 printk("[");
273                                 dump_packet(info, skb,
274                                             iphoff + ih->ihl*4+sizeof(_icmph));
275                                 printk("] ");
276                         }
277
278                         /* Max length: 10 "MTU=65535 " */
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         /* Max Length */
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                 /* 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;
311                 const struct ip_esp_hdr *eh;
312
313                 /* Max length: 10 "PROTO=ESP " */
314                 printk("PROTO=ESP ");
315
316                 if (ntohs(ih->frag_off) & IP_OFFSET)
317                         break;
318
319                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
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                 /* Length: 15 "SPI=0xF1234567 " */
329                 printk("SPI=0x%x ", ntohl(eh->spi));
330                 break;
331         }
332         /* Max length: 10 "PROTO 255 " */
333         default:
334                 printk("PROTO=%u ", ih->protocol);
335         }
336
337         /* Max length: 15 "UID=4294967295 " */
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_uid,
343                                 skb->sk->sk_socket->file->f_gid);
344                 read_unlock_bh(&skb->sk->sk_callback_lock);
345         }
346
347         /* Proto    Max log string length */
348         /* IP:      40+46+6+11+127 = 230 */
349         /* TCP:     10+max(25,20+30+13+9+32+11+127) = 252 */
350         /* UDP:     10+max(25,20) = 35 */
351         /* UDPLITE: 14+max(25,20) = 39 */
352         /* ICMP:    11+max(25, 18+25+max(19,14,24+3+n+10,3+n+10)) = 91+n */
353         /* ESP:     10+max(25)+15 = 50 */
354         /* AH:      9+max(25)+15 = 49 */
355         /* unknown: 10 */
356
357         /* (ICMP allows recursion one level deep) */
358         /* maxlen =  IP + ICMP +  IP + max(TCP,UDP,ICMP,unknown) */
359         /* maxlen = 230+   91  + 230 + 252 = 803 */
360 }
361
362 static struct nf_loginfo default_loginfo = {
363         .type   = NF_LOG_TYPE_LOG,
364         .u = {
365                 .log = {
366                         .level    = 0,
367                         .logflags = NF_LOG_MASK,
368                 },
369         },
370 };
371
372 static void
373 ipt_log_packet(unsigned int pf,
374                unsigned int hooknum,
375                const struct sk_buff *skb,
376                const struct net_device *in,
377                const struct net_device *out,
378                const struct nf_loginfo *loginfo,
379                const char *prefix)
380 {
381         if (!loginfo)
382                 loginfo = &default_loginfo;
383
384         spin_lock_bh(&log_lock);
385         printk("<%d>%sIN=%s OUT=%s ", loginfo->u.log.level,
386                prefix,
387                in ? in->name : "",
388                out ? out->name : "");
389 #ifdef CONFIG_BRIDGE_NETFILTER
390         if (skb->nf_bridge) {
391                 const struct net_device *physindev;
392                 const struct net_device *physoutdev;
393
394                 physindev = skb->nf_bridge->physindev;
395                 if (physindev && in != physindev)
396                         printk("PHYSIN=%s ", physindev->name);
397                 physoutdev = skb->nf_bridge->physoutdev;
398                 if (physoutdev && out != physoutdev)
399                         printk("PHYSOUT=%s ", physoutdev->name);
400         }
401 #endif
402
403         if (in && !out) {
404                 /* MAC logging for input chain only. */
405                 printk("MAC=");
406                 if (skb->dev && skb->dev->hard_header_len
407                     && skb->mac_header != skb->network_header) {
408                         int i;
409                         const unsigned char *p = skb_mac_header(skb);
410                         for (i = 0; i < skb->dev->hard_header_len; i++,p++)
411                                 printk("%02x%c", *p,
412                                        i==skb->dev->hard_header_len - 1
413                                        ? ' ':':');
414                 } else
415                         printk(" ");
416         }
417
418         dump_packet(loginfo, skb, 0);
419         printk("\n");
420         spin_unlock_bh(&log_lock);
421 }
422
423 static unsigned int
424 log_tg(struct sk_buff *skb, const struct net_device *in,
425        const struct net_device *out, unsigned int hooknum,
426        const struct xt_target *target, const void *targinfo)
427 {
428         const struct ipt_log_info *loginfo = targinfo;
429         struct nf_loginfo li;
430
431         li.type = NF_LOG_TYPE_LOG;
432         li.u.log.level = loginfo->level;
433         li.u.log.logflags = loginfo->logflags;
434
435         ipt_log_packet(PF_INET, hooknum, skb, in, out, &li,
436                        loginfo->prefix);
437         return XT_CONTINUE;
438 }
439
440 static bool
441 log_tg_check(const char *tablename, const void *e,
442              const struct xt_target *target, void *targinfo,
443              unsigned int hook_mask)
444 {
445         const struct ipt_log_info *loginfo = targinfo;
446
447         if (loginfo->level >= 8) {
448                 pr_debug("LOG: level %u >= 8\n", loginfo->level);
449                 return false;
450         }
451         if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
452                 pr_debug("LOG: prefix term %i\n",
453                          loginfo->prefix[sizeof(loginfo->prefix)-1]);
454                 return false;
455         }
456         return true;
457 }
458
459 static struct xt_target log_tg_reg __read_mostly = {
460         .name           = "LOG",
461         .family         = AF_INET,
462         .target         = log_tg,
463         .targetsize     = sizeof(struct ipt_log_info),
464         .checkentry     = log_tg_check,
465         .me             = THIS_MODULE,
466 };
467
468 static struct nf_logger ipt_log_logger ={
469         .name           = "ipt_LOG",
470         .logfn          = &ipt_log_packet,
471         .me             = THIS_MODULE,
472 };
473
474 static int __init log_tg_init(void)
475 {
476         int ret;
477
478         ret = xt_register_target(&log_tg_reg);
479         if (ret < 0)
480                 return ret;
481         nf_log_register(PF_INET, &ipt_log_logger);
482         return 0;
483 }
484
485 static void __exit log_tg_exit(void)
486 {
487         nf_log_unregister(&ipt_log_logger);
488         xt_unregister_target(&log_tg_reg);
489 }
490
491 module_init(log_tg_init);
492 module_exit(log_tg_exit);