2 * This is a module which is used for logging packets.
5 /* (C) 1999-2001 Paul `Rusty' Russell
6 * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
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.
13 #include <linux/module.h>
14 #include <linux/spinlock.h>
15 #include <linux/skbuff.h>
20 #include <net/route.h>
22 #include <linux/netfilter.h>
23 #include <linux/netfilter_ipv4/ip_tables.h>
24 #include <linux/netfilter_ipv4/ipt_LOG.h>
26 MODULE_LICENSE("GPL");
27 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
28 MODULE_DESCRIPTION("iptables syslog logging module");
33 #define DEBUGP(format, args...)
36 /* Use lock to serialize, so printks don't overlap */
37 static DEFINE_SPINLOCK(log_lock);
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,
44 struct iphdr _iph, *ih;
45 unsigned int logflags;
47 if (info->type == NF_LOG_TYPE_LOG)
48 logflags = info->u.log.logflags;
50 logflags = NF_LOG_MASK;
52 printk("TAG=%d ", skb->skb_tag);
54 ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph);
61 * TOS, len, DF/MF, fragment offset, TTL, src, dst, options. */
62 /* Max length: 40 "SRC=255.255.255.255 DST=255.255.255.255 " */
63 printk("SRC=%u.%u.%u.%u DST=%u.%u.%u.%u ",
64 NIPQUAD(ih->saddr), NIPQUAD(ih->daddr));
66 /* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */
67 printk("LEN=%u TOS=0x%02X PREC=0x%02X TTL=%u ID=%u ",
68 ntohs(ih->tot_len), ih->tos & IPTOS_TOS_MASK,
69 ih->tos & IPTOS_PREC_MASK, ih->ttl, ntohs(ih->id));
71 /* Max length: 6 "CE DF MF " */
72 if (ntohs(ih->frag_off) & IP_CE)
74 if (ntohs(ih->frag_off) & IP_DF)
76 if (ntohs(ih->frag_off) & IP_MF)
79 /* Max length: 11 "FRAG:65535 " */
80 if (ntohs(ih->frag_off) & IP_OFFSET)
81 printk("FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET);
83 if ((logflags & IPT_LOG_IPOPT)
84 && ih->ihl * 4 > sizeof(struct iphdr)) {
85 unsigned char _opt[4 * 15 - sizeof(struct iphdr)], *op;
86 unsigned int i, optsize;
88 optsize = ih->ihl * 4 - sizeof(struct iphdr);
89 op = skb_header_pointer(skb, iphoff+sizeof(_iph),
96 /* Max length: 127 "OPT (" 15*4*2chars ") " */
98 for (i = 0; i < optsize; i++)
99 printk("%02X", op[i]);
103 switch (ih->protocol) {
105 struct tcphdr _tcph, *th;
107 /* Max length: 10 "PROTO=TCP " */
108 printk("PROTO=TCP ");
110 if (ntohs(ih->frag_off) & IP_OFFSET)
113 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
114 th = skb_header_pointer(skb, iphoff + ih->ihl * 4,
115 sizeof(_tcph), &_tcph);
117 printk("INCOMPLETE [%u bytes] ",
118 skb->len - iphoff - ih->ihl*4);
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 " */
150 /* Max length: 11 "URGP=65535 " */
151 printk("URGP=%u ", ntohs(th->urg_ptr));
153 if ((logflags & IPT_LOG_TCPOPT)
154 && th->doff * 4 > sizeof(struct tcphdr)) {
155 unsigned char _opt[4 * 15 - sizeof(struct tcphdr)];
157 unsigned int i, optsize;
159 optsize = th->doff * 4 - sizeof(struct tcphdr);
160 op = skb_header_pointer(skb,
161 iphoff+ih->ihl*4+sizeof(_tcph),
168 /* Max length: 127 "OPT (" 15*4*2chars ") " */
170 for (i = 0; i < optsize; i++)
171 printk("%02X", op[i]);
177 case IPPROTO_UDPLITE: {
178 struct udphdr _udph, *uh;
180 if (ih->protocol == IPPROTO_UDP)
181 /* Max length: 10 "PROTO=UDP " */
182 printk("PROTO=UDP " );
183 else /* Max length: 14 "PROTO=UDPLITE " */
184 printk("PROTO=UDPLITE ");
186 if (ntohs(ih->frag_off) & IP_OFFSET)
189 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
190 uh = skb_header_pointer(skb, iphoff+ih->ihl*4,
191 sizeof(_udph), &_udph);
193 printk("INCOMPLETE [%u bytes] ",
194 skb->len - iphoff - ih->ihl*4);
198 /* Max length: 20 "SPT=65535 DPT=65535 " */
199 printk("SPT=%u DPT=%u LEN=%u ",
200 ntohs(uh->source), ntohs(uh->dest),
205 struct icmphdr _icmph, *ich;
206 static const size_t required_len[NR_ICMP_TYPES+1]
207 = { [ICMP_ECHOREPLY] = 4,
209 = 8 + sizeof(struct iphdr),
211 = 8 + sizeof(struct iphdr),
213 = 8 + sizeof(struct iphdr),
216 = 8 + sizeof(struct iphdr),
218 = 8 + sizeof(struct iphdr),
219 [ICMP_TIMESTAMP] = 20,
220 [ICMP_TIMESTAMPREPLY] = 20,
222 [ICMP_ADDRESSREPLY] = 12 };
224 /* Max length: 11 "PROTO=ICMP " */
225 printk("PROTO=ICMP ");
227 if (ntohs(ih->frag_off) & IP_OFFSET)
230 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
231 ich = skb_header_pointer(skb, iphoff + ih->ihl * 4,
232 sizeof(_icmph), &_icmph);
234 printk("INCOMPLETE [%u bytes] ",
235 skb->len - iphoff - ih->ihl*4);
239 /* Max length: 18 "TYPE=255 CODE=255 " */
240 printk("TYPE=%u CODE=%u ", ich->type, ich->code);
242 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
243 if (ich->type <= NR_ICMP_TYPES
244 && required_len[ich->type]
245 && skb->len-iphoff-ih->ihl*4 < required_len[ich->type]) {
246 printk("INCOMPLETE [%u bytes] ",
247 skb->len - iphoff - ih->ihl*4);
254 /* Max length: 19 "ID=65535 SEQ=65535 " */
255 printk("ID=%u SEQ=%u ",
256 ntohs(ich->un.echo.id),
257 ntohs(ich->un.echo.sequence));
260 case ICMP_PARAMETERPROB:
261 /* Max length: 14 "PARAMETER=255 " */
262 printk("PARAMETER=%u ",
263 ntohl(ich->un.gateway) >> 24);
266 /* Max length: 24 "GATEWAY=255.255.255.255 " */
267 printk("GATEWAY=%u.%u.%u.%u ",
268 NIPQUAD(ich->un.gateway));
270 case ICMP_DEST_UNREACH:
271 case ICMP_SOURCE_QUENCH:
272 case ICMP_TIME_EXCEEDED:
273 /* Max length: 3+maxlen */
274 if (!iphoff) { /* Only recurse once. */
276 dump_packet(info, skb,
277 iphoff + ih->ihl*4+sizeof(_icmph));
281 /* Max length: 10 "MTU=65535 " */
282 if (ich->type == ICMP_DEST_UNREACH
283 && ich->code == ICMP_FRAG_NEEDED)
284 printk("MTU=%u ", ntohs(ich->un.frag.mtu));
290 struct ip_auth_hdr _ahdr, *ah;
292 if (ntohs(ih->frag_off) & IP_OFFSET)
295 /* Max length: 9 "PROTO=AH " */
298 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
299 ah = skb_header_pointer(skb, iphoff+ih->ihl*4,
300 sizeof(_ahdr), &_ahdr);
302 printk("INCOMPLETE [%u bytes] ",
303 skb->len - iphoff - ih->ihl*4);
307 /* Length: 15 "SPI=0xF1234567 " */
308 printk("SPI=0x%x ", ntohl(ah->spi));
312 struct ip_esp_hdr _esph, *eh;
314 /* Max length: 10 "PROTO=ESP " */
315 printk("PROTO=ESP ");
317 if (ntohs(ih->frag_off) & IP_OFFSET)
320 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
321 eh = skb_header_pointer(skb, iphoff+ih->ihl*4,
322 sizeof(_esph), &_esph);
324 printk("INCOMPLETE [%u bytes] ",
325 skb->len - iphoff - ih->ihl*4);
329 /* Length: 15 "SPI=0xF1234567 " */
330 printk("SPI=0x%x ", ntohl(eh->spi));
333 /* Max length: 10 "PROTO 255 " */
335 printk("PROTO=%u ", ih->protocol);
338 /* Max length: 15 "UID=4294967295 " */
339 if ((logflags & IPT_LOG_UID) && !iphoff && skb->sk) {
340 read_lock_bh(&skb->sk->sk_callback_lock);
341 if (skb->sk->sk_socket && skb->sk->sk_socket->file)
342 printk("UID=%u ", skb->sk->sk_socket->file->f_uid);
343 read_unlock_bh(&skb->sk->sk_callback_lock);
346 /* Proto Max log string length */
347 /* IP: 40+46+6+11+127 = 230 */
348 /* TCP: 10+max(25,20+30+13+9+32+11+127) = 252 */
349 /* UDP: 10+max(25,20) = 35 */
350 /* UDPLITE: 14+max(25,20) = 39 */
351 /* ICMP: 11+max(25, 18+25+max(19,14,24+3+n+10,3+n+10)) = 91+n */
352 /* ESP: 10+max(25)+15 = 50 */
353 /* AH: 9+max(25)+15 = 49 */
356 /* (ICMP allows recursion one level deep) */
357 /* maxlen = IP + ICMP + IP + max(TCP,UDP,ICMP,unknown) */
358 /* maxlen = 230+ 91 + 230 + 252 = 803 */
361 static struct nf_loginfo default_loginfo = {
362 .type = NF_LOG_TYPE_LOG,
366 .logflags = NF_LOG_MASK,
372 ipt_log_packet(unsigned int pf,
373 unsigned int hooknum,
374 const struct sk_buff *skb,
375 const struct net_device *in,
376 const struct net_device *out,
377 const struct nf_loginfo *loginfo,
381 loginfo = &default_loginfo;
383 spin_lock_bh(&log_lock);
384 printk("<%d>%sIN=%s OUT=%s ", loginfo->u.log.level,
387 out ? out->name : "");
388 #ifdef CONFIG_BRIDGE_NETFILTER
389 if (skb->nf_bridge) {
390 struct net_device *physindev = skb->nf_bridge->physindev;
391 struct net_device *physoutdev = skb->nf_bridge->physoutdev;
393 if (physindev && in != physindev)
394 printk("PHYSIN=%s ", physindev->name);
395 if (physoutdev && out != physoutdev)
396 printk("PHYSOUT=%s ", physoutdev->name);
401 /* MAC logging for input chain only. */
403 if (skb->dev && skb->dev->hard_header_len
404 && skb->mac.raw != (void*)skb->nh.iph) {
406 unsigned char *p = skb->mac.raw;
407 for (i = 0; i < skb->dev->hard_header_len; i++,p++)
409 i==skb->dev->hard_header_len - 1
415 dump_packet(loginfo, skb, 0);
417 spin_unlock_bh(&log_lock);
421 ipt_log_target(struct sk_buff **pskb,
422 const struct net_device *in,
423 const struct net_device *out,
424 unsigned int hooknum,
425 const struct xt_target *target,
426 const void *targinfo)
428 const struct ipt_log_info *loginfo = targinfo;
429 struct nf_loginfo li;
431 li.type = NF_LOG_TYPE_LOG;
432 li.u.log.level = loginfo->level;
433 li.u.log.logflags = loginfo->logflags;
435 ipt_log_packet(PF_INET, hooknum, *pskb, in, out, &li,
440 static int ipt_log_checkentry(const char *tablename,
442 const struct xt_target *target,
444 unsigned int hook_mask)
446 const struct ipt_log_info *loginfo = targinfo;
448 if (loginfo->level >= 8) {
449 DEBUGP("LOG: level %u >= 8\n", loginfo->level);
452 if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
453 DEBUGP("LOG: prefix term %i\n",
454 loginfo->prefix[sizeof(loginfo->prefix)-1]);
460 static struct ipt_target ipt_log_reg = {
462 .target = ipt_log_target,
463 .targetsize = sizeof(struct ipt_log_info),
464 .checkentry = ipt_log_checkentry,
468 static struct nf_logger ipt_log_logger ={
470 .logfn = &ipt_log_packet,
474 static int __init ipt_log_init(void)
476 if (ipt_register_target(&ipt_log_reg))
478 if (nf_log_register(PF_INET, &ipt_log_logger) < 0) {
479 printk(KERN_WARNING "ipt_LOG: not logging via system console "
480 "since somebody else already registered for PF_INET\n");
481 /* we cannot make module load fail here, since otherwise
482 * iptables userspace would abort */
488 static void __exit ipt_log_fini(void)
490 nf_log_unregister_logger(&ipt_log_logger);
491 ipt_unregister_target(&ipt_log_reg);
494 module_init(ipt_log_init);
495 module_exit(ipt_log_fini);