[NET]: Supporting UDP-Lite (RFC 3828) in Linux
[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_ipv4/ip_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, *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                 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
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                         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 " */
124                 if (logflags & IPT_LOG_TCPSEQ)
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
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                                 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         }
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                         printk("PROTO=UDP " );
181                 else    /* Max length: 14 "PROTO=UDPLITE " */
182                         printk("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                         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;
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                 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;
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, *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 " */
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                         printk("UID=%u ", skb->sk->sk_socket->file->f_uid);
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 */
348         /* UDPLITE: 14+max(25,20) = 39 */
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
359 static struct nf_loginfo default_loginfo = {
360         .type   = NF_LOG_TYPE_LOG,
361         .u = {
362                 .log = {
363                         .level    = 0,
364                         .logflags = NF_LOG_MASK,
365                 },
366         },
367 };
368
369 static void
370 ipt_log_packet(unsigned int pf,
371                unsigned int hooknum,
372                const struct sk_buff *skb,
373                const struct net_device *in,
374                const struct net_device *out,
375                const struct nf_loginfo *loginfo,
376                const char *prefix)
377 {
378         if (!loginfo)
379                 loginfo = &default_loginfo;
380
381         spin_lock_bh(&log_lock);
382         printk("<%d>%sIN=%s OUT=%s ", loginfo->u.log.level,
383                prefix,
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
402                     && skb->mac.raw != (void*)skb->nh.iph) {
403                         int i;
404                         unsigned char *p = skb->mac.raw;
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,
423                const struct xt_target *target,
424                const void *targinfo)
425 {
426         const struct ipt_log_info *loginfo = targinfo;
427         struct nf_loginfo li;
428
429         li.type = NF_LOG_TYPE_LOG;
430         li.u.log.level = loginfo->level;
431         li.u.log.logflags = loginfo->logflags;
432
433         if (loginfo->logflags & IPT_LOG_NFLOG)
434                 nf_log_packet(PF_INET, hooknum, *pskb, in, out, &li,
435                               "%s", loginfo->prefix);
436         else
437                 ipt_log_packet(PF_INET, hooknum, *pskb, in, out, &li,
438                                loginfo->prefix);
439
440         return IPT_CONTINUE;
441 }
442
443 static int ipt_log_checkentry(const char *tablename,
444                               const void *e,
445                               const struct xt_target *target,
446                               void *targinfo,
447                               unsigned int hook_mask)
448 {
449         const struct ipt_log_info *loginfo = targinfo;
450
451         if (loginfo->level >= 8) {
452                 DEBUGP("LOG: level %u >= 8\n", loginfo->level);
453                 return 0;
454         }
455         if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
456                 DEBUGP("LOG: prefix term %i\n",
457                        loginfo->prefix[sizeof(loginfo->prefix)-1]);
458                 return 0;
459         }
460         return 1;
461 }
462
463 static struct ipt_target ipt_log_reg = {
464         .name           = "LOG",
465         .target         = ipt_log_target,
466         .targetsize     = sizeof(struct ipt_log_info),
467         .checkentry     = ipt_log_checkentry,
468         .me             = THIS_MODULE,
469 };
470
471 static struct nf_logger ipt_log_logger ={
472         .name           = "ipt_LOG",
473         .logfn          = &ipt_log_packet,
474         .me             = THIS_MODULE,
475 };
476
477 static int __init ipt_log_init(void)
478 {
479         if (ipt_register_target(&ipt_log_reg))
480                 return -EINVAL;
481         if (nf_log_register(PF_INET, &ipt_log_logger) < 0) {
482                 printk(KERN_WARNING "ipt_LOG: not logging via system console "
483                        "since somebody else already registered for PF_INET\n");
484                 /* we cannot make module load fail here, since otherwise
485                  * iptables userspace would abort */
486         }
487         
488         return 0;
489 }
490
491 static void __exit ipt_log_fini(void)
492 {
493         nf_log_unregister_logger(&ipt_log_logger);
494         ipt_unregister_target(&ipt_log_reg);
495 }
496
497 module_init(ipt_log_init);
498 module_exit(ipt_log_fini);