[NET]: Supporting UDP-Lite (RFC 3828) in Linux
[linux-2.6.git] / net / ipv6 / netfilter / ip6t_LOG.c
1 /*
2  * This is a module which is used for logging packets.
3  */
4
5 /* (C) 2001 Jan Rekorajski <baggins@pld.org.pl>
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/moduleparam.h>
15 #include <linux/skbuff.h>
16 #include <linux/if_arp.h>
17 #include <linux/ip.h>
18 #include <linux/spinlock.h>
19 #include <linux/icmpv6.h>
20 #include <net/udp.h>
21 #include <net/tcp.h>
22 #include <net/ipv6.h>
23 #include <linux/netfilter.h>
24 #include <linux/netfilter_ipv6/ip6_tables.h>
25
26 MODULE_AUTHOR("Jan Rekorajski <baggins@pld.org.pl>");
27 MODULE_DESCRIPTION("IP6 tables LOG target module");
28 MODULE_LICENSE("GPL");
29
30 struct in_device;
31 #include <net/route.h>
32 #include <linux/netfilter_ipv6/ip6t_LOG.h>
33
34 #if 0
35 #define DEBUGP printk
36 #else
37 #define DEBUGP(format, args...)
38 #endif
39
40 /* Use lock to serialize, so printks don't overlap */
41 static DEFINE_SPINLOCK(log_lock);
42
43 /* One level of recursion won't kill us */
44 static void dump_packet(const struct nf_loginfo *info,
45                         const struct sk_buff *skb, unsigned int ip6hoff,
46                         int recurse)
47 {
48         u_int8_t currenthdr;
49         int fragment;
50         struct ipv6hdr _ip6h, *ih;
51         unsigned int ptr;
52         unsigned int hdrlen = 0;
53         unsigned int logflags;
54
55         if (info->type == NF_LOG_TYPE_LOG)
56                 logflags = info->u.log.logflags;
57         else
58                 logflags = NF_LOG_MASK;
59
60         ih = skb_header_pointer(skb, ip6hoff, sizeof(_ip6h), &_ip6h);
61         if (ih == NULL) {
62                 printk("TRUNCATED");
63                 return;
64         }
65
66         /* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000 " */
67         printk("SRC=" NIP6_FMT " DST=" NIP6_FMT " ", NIP6(ih->saddr), NIP6(ih->daddr));
68
69         /* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
70         printk("LEN=%Zu TC=%u HOPLIMIT=%u FLOWLBL=%u ",
71                ntohs(ih->payload_len) + sizeof(struct ipv6hdr),
72                (ntohl(*(u_int32_t *)ih) & 0x0ff00000) >> 20,
73                ih->hop_limit,
74                (ntohl(*(u_int32_t *)ih) & 0x000fffff));
75
76         fragment = 0;
77         ptr = ip6hoff + sizeof(struct ipv6hdr);
78         currenthdr = ih->nexthdr;
79         while (currenthdr != NEXTHDR_NONE && ip6t_ext_hdr(currenthdr)) {
80                 struct ipv6_opt_hdr _hdr, *hp;
81
82                 hp = skb_header_pointer(skb, ptr, sizeof(_hdr), &_hdr);
83                 if (hp == NULL) {
84                         printk("TRUNCATED");
85                         return;
86                 }
87
88                 /* Max length: 48 "OPT (...) " */
89                 if (logflags & IP6T_LOG_IPOPT)
90                         printk("OPT ( ");
91
92                 switch (currenthdr) {
93                 case IPPROTO_FRAGMENT: {
94                         struct frag_hdr _fhdr, *fh;
95
96                         printk("FRAG:");
97                         fh = skb_header_pointer(skb, ptr, sizeof(_fhdr),
98                                                 &_fhdr);
99                         if (fh == NULL) {
100                                 printk("TRUNCATED ");
101                                 return;
102                         }
103
104                         /* Max length: 6 "65535 " */
105                         printk("%u ", ntohs(fh->frag_off) & 0xFFF8);
106
107                         /* Max length: 11 "INCOMPLETE " */
108                         if (fh->frag_off & htons(0x0001))
109                                 printk("INCOMPLETE ");
110
111                         printk("ID:%08x ", ntohl(fh->identification));
112
113                         if (ntohs(fh->frag_off) & 0xFFF8)
114                                 fragment = 1;
115
116                         hdrlen = 8;
117
118                         break;
119                 }
120                 case IPPROTO_DSTOPTS:
121                 case IPPROTO_ROUTING:
122                 case IPPROTO_HOPOPTS:
123                         if (fragment) {
124                                 if (logflags & IP6T_LOG_IPOPT)
125                                         printk(")");
126                                 return;
127                         }
128                         hdrlen = ipv6_optlen(hp);
129                         break;
130                 /* Max Length */
131                 case IPPROTO_AH:
132                         if (logflags & IP6T_LOG_IPOPT) {
133                                 struct ip_auth_hdr _ahdr, *ah;
134
135                                 /* Max length: 3 "AH " */
136                                 printk("AH ");
137
138                                 if (fragment) {
139                                         printk(")");
140                                         return;
141                                 }
142
143                                 ah = skb_header_pointer(skb, ptr, sizeof(_ahdr),
144                                                         &_ahdr);
145                                 if (ah == NULL) {
146                                         /*
147                                          * Max length: 26 "INCOMPLETE [65535    
148                                          *  bytes] )"
149                                          */
150                                         printk("INCOMPLETE [%u bytes] )",
151                                                skb->len - ptr);
152                                         return;
153                                 }
154
155                                 /* Length: 15 "SPI=0xF1234567 */
156                                 printk("SPI=0x%x ", ntohl(ah->spi));
157
158                         }
159
160                         hdrlen = (hp->hdrlen+2)<<2;
161                         break;
162                 case IPPROTO_ESP:
163                         if (logflags & IP6T_LOG_IPOPT) {
164                                 struct ip_esp_hdr _esph, *eh;
165
166                                 /* Max length: 4 "ESP " */
167                                 printk("ESP ");
168
169                                 if (fragment) {
170                                         printk(")");
171                                         return;
172                                 }
173
174                                 /*
175                                  * Max length: 26 "INCOMPLETE [65535 bytes] )"
176                                  */
177                                 eh = skb_header_pointer(skb, ptr, sizeof(_esph),
178                                                         &_esph);
179                                 if (eh == NULL) {
180                                         printk("INCOMPLETE [%u bytes] )",
181                                                skb->len - ptr);
182                                         return;
183                                 }
184
185                                 /* Length: 16 "SPI=0xF1234567 )" */
186                                 printk("SPI=0x%x )", ntohl(eh->spi) );
187
188                         }
189                         return;
190                 default:
191                         /* Max length: 20 "Unknown Ext Hdr 255" */
192                         printk("Unknown Ext Hdr %u", currenthdr);
193                         return;
194                 }
195                 if (logflags & IP6T_LOG_IPOPT)
196                         printk(") ");
197
198                 currenthdr = hp->nexthdr;
199                 ptr += hdrlen;
200         }
201
202         switch (currenthdr) {
203         case IPPROTO_TCP: {
204                 struct tcphdr _tcph, *th;
205
206                 /* Max length: 10 "PROTO=TCP " */
207                 printk("PROTO=TCP ");
208
209                 if (fragment)
210                         break;
211
212                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
213                 th = skb_header_pointer(skb, ptr, sizeof(_tcph), &_tcph);
214                 if (th == NULL) {
215                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
216                         return;
217                 }
218
219                 /* Max length: 20 "SPT=65535 DPT=65535 " */
220                 printk("SPT=%u DPT=%u ",
221                        ntohs(th->source), ntohs(th->dest));
222                 /* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
223                 if (logflags & IP6T_LOG_TCPSEQ)
224                         printk("SEQ=%u ACK=%u ",
225                                ntohl(th->seq), ntohl(th->ack_seq));
226                 /* Max length: 13 "WINDOW=65535 " */
227                 printk("WINDOW=%u ", ntohs(th->window));
228                 /* Max length: 9 "RES=0x3C " */
229                 printk("RES=0x%02x ", (u_int8_t)(ntohl(tcp_flag_word(th) & TCP_RESERVED_BITS) >> 22));
230                 /* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
231                 if (th->cwr)
232                         printk("CWR ");
233                 if (th->ece)
234                         printk("ECE ");
235                 if (th->urg)
236                         printk("URG ");
237                 if (th->ack)
238                         printk("ACK ");
239                 if (th->psh)
240                         printk("PSH ");
241                 if (th->rst)
242                         printk("RST ");
243                 if (th->syn)
244                         printk("SYN ");
245                 if (th->fin)
246                         printk("FIN ");
247                 /* Max length: 11 "URGP=65535 " */
248                 printk("URGP=%u ", ntohs(th->urg_ptr));
249
250                 if ((logflags & IP6T_LOG_TCPOPT)
251                     && th->doff * 4 > sizeof(struct tcphdr)) {
252                         u_int8_t _opt[60 - sizeof(struct tcphdr)], *op;
253                         unsigned int i;
254                         unsigned int optsize = th->doff * 4
255                                                - sizeof(struct tcphdr);
256
257                         op = skb_header_pointer(skb,
258                                                 ptr + sizeof(struct tcphdr),
259                                                 optsize, _opt);
260                         if (op == NULL) {
261                                 printk("OPT (TRUNCATED)");
262                                 return;
263                         }
264
265                         /* Max length: 127 "OPT (" 15*4*2chars ") " */
266                         printk("OPT (");
267                         for (i =0; i < optsize; i++)
268                                 printk("%02X", op[i]);
269                         printk(") ");
270                 }
271                 break;
272         }
273         case IPPROTO_UDP:
274         case IPPROTO_UDPLITE: {
275                 struct udphdr _udph, *uh;
276
277                 if (currenthdr == IPPROTO_UDP)
278                         /* Max length: 10 "PROTO=UDP "     */
279                         printk("PROTO=UDP " );
280                 else    /* Max length: 14 "PROTO=UDPLITE " */
281                         printk("PROTO=UDPLITE ");
282
283                 if (fragment)
284                         break;
285
286                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
287                 uh = skb_header_pointer(skb, ptr, sizeof(_udph), &_udph);
288                 if (uh == NULL) {
289                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
290                         return;
291                 }
292
293                 /* Max length: 20 "SPT=65535 DPT=65535 " */
294                 printk("SPT=%u DPT=%u LEN=%u ",
295                        ntohs(uh->source), ntohs(uh->dest),
296                        ntohs(uh->len));
297                 break;
298         }
299         case IPPROTO_ICMPV6: {
300                 struct icmp6hdr _icmp6h, *ic;
301
302                 /* Max length: 13 "PROTO=ICMPv6 " */
303                 printk("PROTO=ICMPv6 ");
304
305                 if (fragment)
306                         break;
307
308                 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
309                 ic = skb_header_pointer(skb, ptr, sizeof(_icmp6h), &_icmp6h);
310                 if (ic == NULL) {
311                         printk("INCOMPLETE [%u bytes] ", skb->len - ptr);
312                         return;
313                 }
314
315                 /* Max length: 18 "TYPE=255 CODE=255 " */
316                 printk("TYPE=%u CODE=%u ", ic->icmp6_type, ic->icmp6_code);
317
318                 switch (ic->icmp6_type) {
319                 case ICMPV6_ECHO_REQUEST:
320                 case ICMPV6_ECHO_REPLY:
321                         /* Max length: 19 "ID=65535 SEQ=65535 " */
322                         printk("ID=%u SEQ=%u ",
323                                 ntohs(ic->icmp6_identifier),
324                                 ntohs(ic->icmp6_sequence));
325                         break;
326                 case ICMPV6_MGM_QUERY:
327                 case ICMPV6_MGM_REPORT:
328                 case ICMPV6_MGM_REDUCTION:
329                         break;
330
331                 case ICMPV6_PARAMPROB:
332                         /* Max length: 17 "POINTER=ffffffff " */
333                         printk("POINTER=%08x ", ntohl(ic->icmp6_pointer));
334                         /* Fall through */
335                 case ICMPV6_DEST_UNREACH:
336                 case ICMPV6_PKT_TOOBIG:
337                 case ICMPV6_TIME_EXCEED:
338                         /* Max length: 3+maxlen */
339                         if (recurse) {
340                                 printk("[");
341                                 dump_packet(info, skb, ptr + sizeof(_icmp6h),
342                                             0);
343                                 printk("] ");
344                         }
345
346                         /* Max length: 10 "MTU=65535 " */
347                         if (ic->icmp6_type == ICMPV6_PKT_TOOBIG)
348                                 printk("MTU=%u ", ntohl(ic->icmp6_mtu));
349                 }
350                 break;
351         }
352         /* Max length: 10 "PROTO=255 " */
353         default:
354                 printk("PROTO=%u ", currenthdr);
355         }
356
357         /* Max length: 15 "UID=4294967295 " */
358         if ((logflags & IP6T_LOG_UID) && recurse && skb->sk) {
359                 read_lock_bh(&skb->sk->sk_callback_lock);
360                 if (skb->sk->sk_socket && skb->sk->sk_socket->file)
361                         printk("UID=%u ", skb->sk->sk_socket->file->f_uid);
362                 read_unlock_bh(&skb->sk->sk_callback_lock);
363         }
364 }
365
366 static struct nf_loginfo default_loginfo = {
367         .type   = NF_LOG_TYPE_LOG,
368         .u = {
369                 .log = {
370                         .level    = 0,
371                         .logflags = NF_LOG_MASK,
372                 },
373         },
374 };
375
376 static void
377 ip6t_log_packet(unsigned int pf,
378                 unsigned int hooknum,
379                 const struct sk_buff *skb,
380                 const struct net_device *in,
381                 const struct net_device *out,
382                 const struct nf_loginfo *loginfo,
383                 const char *prefix)
384 {
385         if (!loginfo)
386                 loginfo = &default_loginfo;
387
388         spin_lock_bh(&log_lock);
389         printk("<%d>%sIN=%s OUT=%s ", loginfo->u.log.level, 
390                 prefix,
391                 in ? in->name : "",
392                 out ? out->name : "");
393         if (in && !out) {
394                 unsigned int len;
395                 /* MAC logging for input chain only. */
396                 printk("MAC=");
397                 if (skb->dev && (len = skb->dev->hard_header_len) &&
398                     skb->mac.raw != skb->nh.raw) {
399                         unsigned char *p = skb->mac.raw;
400                         int i;
401
402                         if (skb->dev->type == ARPHRD_SIT &&
403                             (p -= ETH_HLEN) < skb->head)
404                                 p = NULL;
405
406                         if (p != NULL) {
407                                 for (i = 0; i < len; i++)
408                                         printk("%02x%s", p[i],
409                                                i == len - 1 ? "" : ":");
410                         }
411                         printk(" ");
412
413                         if (skb->dev->type == ARPHRD_SIT) {
414                                 struct iphdr *iph = (struct iphdr *)skb->mac.raw;
415                                 printk("TUNNEL=%u.%u.%u.%u->%u.%u.%u.%u ",
416                                        NIPQUAD(iph->saddr),
417                                        NIPQUAD(iph->daddr));
418                         }
419                 } else
420                         printk(" ");
421         }
422
423         dump_packet(loginfo, skb, (u8*)skb->nh.ipv6h - skb->data, 1);
424         printk("\n");
425         spin_unlock_bh(&log_lock);
426 }
427
428 static unsigned int
429 ip6t_log_target(struct sk_buff **pskb,
430                 const struct net_device *in,
431                 const struct net_device *out,
432                 unsigned int hooknum,
433                 const struct xt_target *target,
434                 const void *targinfo)
435 {
436         const struct ip6t_log_info *loginfo = targinfo;
437         struct nf_loginfo li;
438
439         li.type = NF_LOG_TYPE_LOG;
440         li.u.log.level = loginfo->level;
441         li.u.log.logflags = loginfo->logflags;
442
443         if (loginfo->logflags & IP6T_LOG_NFLOG)
444                 nf_log_packet(PF_INET6, hooknum, *pskb, in, out, &li,
445                               "%s", loginfo->prefix);
446         else
447                 ip6t_log_packet(PF_INET6, hooknum, *pskb, in, out, &li,
448                                 loginfo->prefix);
449
450         return IP6T_CONTINUE;
451 }
452
453
454 static int ip6t_log_checkentry(const char *tablename,
455                                const void *entry,
456                                const struct xt_target *target,
457                                void *targinfo,
458                                unsigned int hook_mask)
459 {
460         const struct ip6t_log_info *loginfo = targinfo;
461
462         if (loginfo->level >= 8) {
463                 DEBUGP("LOG: level %u >= 8\n", loginfo->level);
464                 return 0;
465         }
466         if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
467                 DEBUGP("LOG: prefix term %i\n",
468                        loginfo->prefix[sizeof(loginfo->prefix)-1]);
469                 return 0;
470         }
471         return 1;
472 }
473
474 static struct ip6t_target ip6t_log_reg = {
475         .name           = "LOG",
476         .target         = ip6t_log_target, 
477         .targetsize     = sizeof(struct ip6t_log_info),
478         .checkentry     = ip6t_log_checkentry, 
479         .me             = THIS_MODULE,
480 };
481
482 static struct nf_logger ip6t_logger = {
483         .name           = "ip6t_LOG",
484         .logfn          = &ip6t_log_packet,
485         .me             = THIS_MODULE,
486 };
487
488 static int __init ip6t_log_init(void)
489 {
490         if (ip6t_register_target(&ip6t_log_reg))
491                 return -EINVAL;
492         if (nf_log_register(PF_INET6, &ip6t_logger) < 0) {
493                 printk(KERN_WARNING "ip6t_LOG: not logging via system console "
494                        "since somebody else already registered for PF_INET6\n");
495                 /* we cannot make module load fail here, since otherwise
496                  * ip6tables userspace would abort */
497         }
498
499         return 0;
500 }
501
502 static void __exit ip6t_log_fini(void)
503 {
504         nf_log_unregister_logger(&ip6t_logger);
505         ip6t_unregister_target(&ip6t_log_reg);
506 }
507
508 module_init(ip6t_log_init);
509 module_exit(ip6t_log_fini);