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");
30 static unsigned int nflog = 1;
31 module_param(nflog, int, 0400);
32 MODULE_PARM_DESC(nflog, "register as internal netfilter logging module");
37 #define DEBUGP(format, args...)
40 /* Use lock to serialize, so printks don't overlap */
41 static DEFINE_SPINLOCK(log_lock);
43 /* One level of recursion won't kill us */
44 static void dump_packet(const struct ipt_log_info *info,
45 const struct sk_buff *skb,
48 struct iphdr _iph, *ih;
50 ih = skb_header_pointer(skb, iphoff, sizeof(_iph), &_iph);
57 * TOS, len, DF/MF, fragment offset, TTL, src, dst, options. */
58 /* Max length: 40 "SRC=255.255.255.255 DST=255.255.255.255 " */
59 printk("SRC=%u.%u.%u.%u DST=%u.%u.%u.%u ",
60 NIPQUAD(ih->saddr), NIPQUAD(ih->daddr));
62 /* Max length: 46 "LEN=65535 TOS=0xFF PREC=0xFF TTL=255 ID=65535 " */
63 printk("LEN=%u TOS=0x%02X PREC=0x%02X TTL=%u ID=%u ",
64 ntohs(ih->tot_len), ih->tos & IPTOS_TOS_MASK,
65 ih->tos & IPTOS_PREC_MASK, ih->ttl, ntohs(ih->id));
67 /* Max length: 6 "CE DF MF " */
68 if (ntohs(ih->frag_off) & IP_CE)
70 if (ntohs(ih->frag_off) & IP_DF)
72 if (ntohs(ih->frag_off) & IP_MF)
75 /* Max length: 11 "FRAG:65535 " */
76 if (ntohs(ih->frag_off) & IP_OFFSET)
77 printk("FRAG:%u ", ntohs(ih->frag_off) & IP_OFFSET);
79 if ((info->logflags & IPT_LOG_IPOPT)
80 && ih->ihl * 4 > sizeof(struct iphdr)) {
81 unsigned char _opt[4 * 15 - sizeof(struct iphdr)], *op;
82 unsigned int i, optsize;
84 optsize = ih->ihl * 4 - sizeof(struct iphdr);
85 op = skb_header_pointer(skb, iphoff+sizeof(_iph),
92 /* Max length: 127 "OPT (" 15*4*2chars ") " */
94 for (i = 0; i < optsize; i++)
95 printk("%02X", op[i]);
99 switch (ih->protocol) {
101 struct tcphdr _tcph, *th;
103 /* Max length: 10 "PROTO=TCP " */
104 printk("PROTO=TCP ");
106 if (ntohs(ih->frag_off) & IP_OFFSET)
109 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
110 th = skb_header_pointer(skb, iphoff + ih->ihl * 4,
111 sizeof(_tcph), &_tcph);
113 printk("INCOMPLETE [%u bytes] ",
114 skb->len - iphoff - ih->ihl*4);
118 /* Max length: 20 "SPT=65535 DPT=65535 " */
119 printk("SPT=%u DPT=%u ",
120 ntohs(th->source), ntohs(th->dest));
121 /* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
122 if (info->logflags & IPT_LOG_TCPSEQ)
123 printk("SEQ=%u ACK=%u ",
124 ntohl(th->seq), ntohl(th->ack_seq));
125 /* Max length: 13 "WINDOW=65535 " */
126 printk("WINDOW=%u ", ntohs(th->window));
127 /* Max length: 9 "RES=0x3F " */
128 printk("RES=0x%02x ", (u8)(ntohl(tcp_flag_word(th) & TCP_RESERVED_BITS) >> 22));
129 /* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
146 /* Max length: 11 "URGP=65535 " */
147 printk("URGP=%u ", ntohs(th->urg_ptr));
149 if ((info->logflags & IPT_LOG_TCPOPT)
150 && th->doff * 4 > sizeof(struct tcphdr)) {
151 unsigned char _opt[4 * 15 - sizeof(struct tcphdr)];
153 unsigned int i, optsize;
155 optsize = th->doff * 4 - sizeof(struct tcphdr);
156 op = skb_header_pointer(skb,
157 iphoff+ih->ihl*4+sizeof(_tcph),
164 /* Max length: 127 "OPT (" 15*4*2chars ") " */
166 for (i = 0; i < optsize; i++)
167 printk("%02X", op[i]);
173 struct udphdr _udph, *uh;
175 /* Max length: 10 "PROTO=UDP " */
176 printk("PROTO=UDP ");
178 if (ntohs(ih->frag_off) & IP_OFFSET)
181 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
182 uh = skb_header_pointer(skb, iphoff+ih->ihl*4,
183 sizeof(_udph), &_udph);
185 printk("INCOMPLETE [%u bytes] ",
186 skb->len - iphoff - ih->ihl*4);
190 /* Max length: 20 "SPT=65535 DPT=65535 " */
191 printk("SPT=%u DPT=%u LEN=%u ",
192 ntohs(uh->source), ntohs(uh->dest),
197 struct icmphdr _icmph, *ich;
198 static size_t required_len[NR_ICMP_TYPES+1]
199 = { [ICMP_ECHOREPLY] = 4,
201 = 8 + sizeof(struct iphdr),
203 = 8 + sizeof(struct iphdr),
205 = 8 + sizeof(struct iphdr),
208 = 8 + sizeof(struct iphdr),
210 = 8 + sizeof(struct iphdr),
211 [ICMP_TIMESTAMP] = 20,
212 [ICMP_TIMESTAMPREPLY] = 20,
214 [ICMP_ADDRESSREPLY] = 12 };
216 /* Max length: 11 "PROTO=ICMP " */
217 printk("PROTO=ICMP ");
219 if (ntohs(ih->frag_off) & IP_OFFSET)
222 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
223 ich = skb_header_pointer(skb, iphoff + ih->ihl * 4,
224 sizeof(_icmph), &_icmph);
226 printk("INCOMPLETE [%u bytes] ",
227 skb->len - iphoff - ih->ihl*4);
231 /* Max length: 18 "TYPE=255 CODE=255 " */
232 printk("TYPE=%u CODE=%u ", ich->type, ich->code);
234 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
235 if (ich->type <= NR_ICMP_TYPES
236 && required_len[ich->type]
237 && skb->len-iphoff-ih->ihl*4 < required_len[ich->type]) {
238 printk("INCOMPLETE [%u bytes] ",
239 skb->len - iphoff - ih->ihl*4);
246 /* Max length: 19 "ID=65535 SEQ=65535 " */
247 printk("ID=%u SEQ=%u ",
248 ntohs(ich->un.echo.id),
249 ntohs(ich->un.echo.sequence));
252 case ICMP_PARAMETERPROB:
253 /* Max length: 14 "PARAMETER=255 " */
254 printk("PARAMETER=%u ",
255 ntohl(ich->un.gateway) >> 24);
258 /* Max length: 24 "GATEWAY=255.255.255.255 " */
259 printk("GATEWAY=%u.%u.%u.%u ",
260 NIPQUAD(ich->un.gateway));
262 case ICMP_DEST_UNREACH:
263 case ICMP_SOURCE_QUENCH:
264 case ICMP_TIME_EXCEEDED:
265 /* Max length: 3+maxlen */
266 if (!iphoff) { /* Only recurse once. */
268 dump_packet(info, skb,
269 iphoff + ih->ihl*4+sizeof(_icmph));
273 /* Max length: 10 "MTU=65535 " */
274 if (ich->type == ICMP_DEST_UNREACH
275 && ich->code == ICMP_FRAG_NEEDED)
276 printk("MTU=%u ", ntohs(ich->un.frag.mtu));
282 struct ip_auth_hdr _ahdr, *ah;
284 if (ntohs(ih->frag_off) & IP_OFFSET)
287 /* Max length: 9 "PROTO=AH " */
290 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
291 ah = skb_header_pointer(skb, iphoff+ih->ihl*4,
292 sizeof(_ahdr), &_ahdr);
294 printk("INCOMPLETE [%u bytes] ",
295 skb->len - iphoff - ih->ihl*4);
299 /* Length: 15 "SPI=0xF1234567 " */
300 printk("SPI=0x%x ", ntohl(ah->spi));
304 struct ip_esp_hdr _esph, *eh;
306 /* Max length: 10 "PROTO=ESP " */
307 printk("PROTO=ESP ");
309 if (ntohs(ih->frag_off) & IP_OFFSET)
312 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
313 eh = skb_header_pointer(skb, iphoff+ih->ihl*4,
314 sizeof(_esph), &_esph);
316 printk("INCOMPLETE [%u bytes] ",
317 skb->len - iphoff - ih->ihl*4);
321 /* Length: 15 "SPI=0xF1234567 " */
322 printk("SPI=0x%x ", ntohl(eh->spi));
325 /* Max length: 10 "PROTO 255 " */
327 printk("PROTO=%u ", ih->protocol);
330 /* Max length: 15 "UID=4294967295 " */
331 if ((info->logflags & IPT_LOG_UID) && !iphoff && skb->sk) {
332 read_lock_bh(&skb->sk->sk_callback_lock);
333 if (skb->sk->sk_socket && skb->sk->sk_socket->file)
334 printk("UID=%u ", skb->sk->sk_socket->file->f_uid);
335 read_unlock_bh(&skb->sk->sk_callback_lock);
338 /* Proto Max log string length */
339 /* IP: 40+46+6+11+127 = 230 */
340 /* TCP: 10+max(25,20+30+13+9+32+11+127) = 252 */
341 /* UDP: 10+max(25,20) = 35 */
342 /* ICMP: 11+max(25, 18+25+max(19,14,24+3+n+10,3+n+10)) = 91+n */
343 /* ESP: 10+max(25)+15 = 50 */
344 /* AH: 9+max(25)+15 = 49 */
347 /* (ICMP allows recursion one level deep) */
348 /* maxlen = IP + ICMP + IP + max(TCP,UDP,ICMP,unknown) */
349 /* maxlen = 230+ 91 + 230 + 252 = 803 */
353 ipt_log_packet(unsigned int hooknum,
354 const struct sk_buff *skb,
355 const struct net_device *in,
356 const struct net_device *out,
357 const struct ipt_log_info *loginfo,
358 const char *level_string,
361 spin_lock_bh(&log_lock);
362 printk(level_string);
363 printk("%sIN=%s OUT=%s ",
364 prefix == NULL ? loginfo->prefix : prefix,
366 out ? out->name : "");
367 #ifdef CONFIG_BRIDGE_NETFILTER
368 if (skb->nf_bridge) {
369 struct net_device *physindev = skb->nf_bridge->physindev;
370 struct net_device *physoutdev = skb->nf_bridge->physoutdev;
372 if (physindev && in != physindev)
373 printk("PHYSIN=%s ", physindev->name);
374 if (physoutdev && out != physoutdev)
375 printk("PHYSOUT=%s ", physoutdev->name);
380 /* MAC logging for input chain only. */
382 if (skb->dev && skb->dev->hard_header_len
383 && skb->mac.raw != (void*)skb->nh.iph) {
385 unsigned char *p = skb->mac.raw;
386 for (i = 0; i < skb->dev->hard_header_len; i++,p++)
388 i==skb->dev->hard_header_len - 1
394 dump_packet(loginfo, skb, 0);
396 spin_unlock_bh(&log_lock);
400 ipt_log_target(struct sk_buff **pskb,
401 const struct net_device *in,
402 const struct net_device *out,
403 unsigned int hooknum,
404 const void *targinfo,
407 const struct ipt_log_info *loginfo = targinfo;
408 char level_string[4] = "< >";
410 level_string[1] = '0' + (loginfo->level % 8);
411 ipt_log_packet(hooknum, *pskb, in, out, loginfo, level_string, NULL);
417 ipt_logfn(unsigned int hooknum,
418 const struct sk_buff *skb,
419 const struct net_device *in,
420 const struct net_device *out,
423 struct ipt_log_info loginfo = {
425 .logflags = IPT_LOG_MASK,
429 ipt_log_packet(hooknum, skb, in, out, &loginfo, KERN_WARNING, prefix);
432 static int ipt_log_checkentry(const char *tablename,
433 const struct ipt_entry *e,
435 unsigned int targinfosize,
436 unsigned int hook_mask)
438 const struct ipt_log_info *loginfo = targinfo;
440 if (targinfosize != IPT_ALIGN(sizeof(struct ipt_log_info))) {
441 DEBUGP("LOG: targinfosize %u != %u\n",
442 targinfosize, IPT_ALIGN(sizeof(struct ipt_log_info)));
446 if (loginfo->level >= 8) {
447 DEBUGP("LOG: level %u >= 8\n", loginfo->level);
451 if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
452 DEBUGP("LOG: prefix term %i\n",
453 loginfo->prefix[sizeof(loginfo->prefix)-1]);
460 static struct ipt_target ipt_log_reg = {
462 .target = ipt_log_target,
463 .checkentry = ipt_log_checkentry,
467 static int __init init(void)
469 if (ipt_register_target(&ipt_log_reg))
472 nf_log_register(PF_INET, &ipt_logfn);
477 static void __exit fini(void)
480 nf_log_unregister(PF_INET, &ipt_logfn);
481 ipt_unregister_target(&ipt_log_reg);