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/x_tables.h>
24 #include <linux/netfilter_ipv4/ipt_LOG.h>
25 #include <net/netfilter/nf_log.h>
27 MODULE_LICENSE("GPL");
28 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
29 MODULE_DESCRIPTION("Xtables: IPv4 packet logging to syslog");
31 /* Use lock to serialize, so printks don't overlap */
32 static DEFINE_SPINLOCK(log_lock
);
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
,
40 const struct iphdr
*ih
;
41 unsigned int logflags
;
43 if (info
->type
== NF_LOG_TYPE_LOG
)
44 logflags
= info
->u
.log
.logflags
;
46 logflags
= NF_LOG_MASK
;
48 ih
= skb_header_pointer(skb
, iphoff
, sizeof(_iph
), &_iph
);
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=%pI4 DST=%pI4 ",
58 &ih
->saddr
, &ih
->daddr
);
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
));
65 /* Max length: 6 "CE DF MF " */
66 if (ntohs(ih
->frag_off
) & IP_CE
)
68 if (ntohs(ih
->frag_off
) & IP_DF
)
70 if (ntohs(ih
->frag_off
) & IP_MF
)
73 /* Max length: 11 "FRAG:65535 " */
74 if (ntohs(ih
->frag_off
) & IP_OFFSET
)
75 printk("FRAG:%u ", ntohs(ih
->frag_off
) & IP_OFFSET
);
77 if ((logflags
& IPT_LOG_IPOPT
)
78 && ih
->ihl
* 4 > sizeof(struct iphdr
)) {
79 const unsigned char *op
;
80 unsigned char _opt
[4 * 15 - sizeof(struct iphdr
)];
81 unsigned int i
, optsize
;
83 optsize
= ih
->ihl
* 4 - sizeof(struct iphdr
);
84 op
= skb_header_pointer(skb
, iphoff
+sizeof(_iph
),
91 /* Max length: 127 "OPT (" 15*4*2chars ") " */
93 for (i
= 0; i
< optsize
; i
++)
94 printk("%02X", op
[i
]);
98 switch (ih
->protocol
) {
101 const struct tcphdr
*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 (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 ((logflags
& IPT_LOG_TCPOPT
)
150 && th
->doff
* 4 > sizeof(struct tcphdr
)) {
151 unsigned char _opt
[4 * 15 - sizeof(struct tcphdr
)];
152 const unsigned char *op
;
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 case IPPROTO_UDPLITE
: {
175 const struct udphdr
*uh
;
177 if (ih
->protocol
== IPPROTO_UDP
)
178 /* Max length: 10 "PROTO=UDP " */
179 printk("PROTO=UDP " );
180 else /* Max length: 14 "PROTO=UDPLITE " */
181 printk("PROTO=UDPLITE ");
183 if (ntohs(ih
->frag_off
) & IP_OFFSET
)
186 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
187 uh
= skb_header_pointer(skb
, iphoff
+ih
->ihl
*4,
188 sizeof(_udph
), &_udph
);
190 printk("INCOMPLETE [%u bytes] ",
191 skb
->len
- iphoff
- ih
->ihl
*4);
195 /* Max length: 20 "SPT=65535 DPT=65535 " */
196 printk("SPT=%u DPT=%u LEN=%u ",
197 ntohs(uh
->source
), ntohs(uh
->dest
),
202 struct icmphdr _icmph
;
203 const struct icmphdr
*ich
;
204 static const size_t required_len
[NR_ICMP_TYPES
+1]
205 = { [ICMP_ECHOREPLY
] = 4,
207 = 8 + sizeof(struct iphdr
),
209 = 8 + sizeof(struct iphdr
),
211 = 8 + sizeof(struct iphdr
),
214 = 8 + sizeof(struct iphdr
),
216 = 8 + sizeof(struct iphdr
),
217 [ICMP_TIMESTAMP
] = 20,
218 [ICMP_TIMESTAMPREPLY
] = 20,
220 [ICMP_ADDRESSREPLY
] = 12 };
222 /* Max length: 11 "PROTO=ICMP " */
223 printk("PROTO=ICMP ");
225 if (ntohs(ih
->frag_off
) & IP_OFFSET
)
228 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
229 ich
= skb_header_pointer(skb
, iphoff
+ ih
->ihl
* 4,
230 sizeof(_icmph
), &_icmph
);
232 printk("INCOMPLETE [%u bytes] ",
233 skb
->len
- iphoff
- ih
->ihl
*4);
237 /* Max length: 18 "TYPE=255 CODE=255 " */
238 printk("TYPE=%u CODE=%u ", ich
->type
, ich
->code
);
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);
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
));
258 case ICMP_PARAMETERPROB
:
259 /* Max length: 14 "PARAMETER=255 " */
260 printk("PARAMETER=%u ",
261 ntohl(ich
->un
.gateway
) >> 24);
264 /* Max length: 24 "GATEWAY=255.255.255.255 " */
265 printk("GATEWAY=%pI4 ", &ich
->un
.gateway
);
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. */
273 dump_packet(info
, skb
,
274 iphoff
+ ih
->ihl
*4+sizeof(_icmph
));
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
));
287 struct ip_auth_hdr _ahdr
;
288 const struct ip_auth_hdr
*ah
;
290 if (ntohs(ih
->frag_off
) & IP_OFFSET
)
293 /* Max length: 9 "PROTO=AH " */
296 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
297 ah
= skb_header_pointer(skb
, iphoff
+ih
->ihl
*4,
298 sizeof(_ahdr
), &_ahdr
);
300 printk("INCOMPLETE [%u bytes] ",
301 skb
->len
- iphoff
- ih
->ihl
*4);
305 /* Length: 15 "SPI=0xF1234567 " */
306 printk("SPI=0x%x ", ntohl(ah
->spi
));
310 struct ip_esp_hdr _esph
;
311 const struct ip_esp_hdr
*eh
;
313 /* Max length: 10 "PROTO=ESP " */
314 printk("PROTO=ESP ");
316 if (ntohs(ih
->frag_off
) & IP_OFFSET
)
319 /* Max length: 25 "INCOMPLETE [65535 bytes] " */
320 eh
= skb_header_pointer(skb
, iphoff
+ih
->ihl
*4,
321 sizeof(_esph
), &_esph
);
323 printk("INCOMPLETE [%u bytes] ",
324 skb
->len
- iphoff
- ih
->ihl
*4);
328 /* Length: 15 "SPI=0xF1234567 " */
329 printk("SPI=0x%x ", ntohl(eh
->spi
));
332 /* Max length: 10 "PROTO 255 " */
334 printk("PROTO=%u ", ih
->protocol
);
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_cred
->fsuid
,
343 skb
->sk
->sk_socket
->file
->f_cred
->fsgid
);
344 read_unlock_bh(&skb
->sk
->sk_callback_lock
);
347 /* Max length: 16 "MARK=0xFFFFFFFF " */
348 if (!iphoff
&& skb
->mark
)
349 printk("MARK=0x%x ", skb
->mark
);
351 /* Proto Max log string length */
352 /* IP: 40+46+6+11+127 = 230 */
353 /* TCP: 10+max(25,20+30+13+9+32+11+127) = 252 */
354 /* UDP: 10+max(25,20) = 35 */
355 /* UDPLITE: 14+max(25,20) = 39 */
356 /* ICMP: 11+max(25, 18+25+max(19,14,24+3+n+10,3+n+10)) = 91+n */
357 /* ESP: 10+max(25)+15 = 50 */
358 /* AH: 9+max(25)+15 = 49 */
361 /* (ICMP allows recursion one level deep) */
362 /* maxlen = IP + ICMP + IP + max(TCP,UDP,ICMP,unknown) */
363 /* maxlen = 230+ 91 + 230 + 252 = 803 */
366 static struct nf_loginfo default_loginfo
= {
367 .type
= NF_LOG_TYPE_LOG
,
371 .logflags
= NF_LOG_MASK
,
377 ipt_log_packet(u_int8_t 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
,
386 loginfo
= &default_loginfo
;
388 spin_lock_bh(&log_lock
);
389 printk("<%d>%sIN=%s OUT=%s ", loginfo
->u
.log
.level
,
392 out
? out
->name
: "");
393 #ifdef CONFIG_BRIDGE_NETFILTER
394 if (skb
->nf_bridge
) {
395 const struct net_device
*physindev
;
396 const struct net_device
*physoutdev
;
398 physindev
= skb
->nf_bridge
->physindev
;
399 if (physindev
&& in
!= physindev
)
400 printk("PHYSIN=%s ", physindev
->name
);
401 physoutdev
= skb
->nf_bridge
->physoutdev
;
402 if (physoutdev
&& out
!= physoutdev
)
403 printk("PHYSOUT=%s ", physoutdev
->name
);
408 /* MAC logging for input chain only. */
410 if (skb
->dev
&& skb
->dev
->hard_header_len
411 && skb
->mac_header
!= skb
->network_header
) {
413 const unsigned char *p
= skb_mac_header(skb
);
414 for (i
= 0; i
< skb
->dev
->hard_header_len
; i
++,p
++)
416 i
==skb
->dev
->hard_header_len
- 1
422 dump_packet(loginfo
, skb
, 0);
424 spin_unlock_bh(&log_lock
);
428 log_tg(struct sk_buff
*skb
, const struct xt_target_param
*par
)
430 const struct ipt_log_info
*loginfo
= par
->targinfo
;
431 struct nf_loginfo li
;
433 li
.type
= NF_LOG_TYPE_LOG
;
434 li
.u
.log
.level
= loginfo
->level
;
435 li
.u
.log
.logflags
= loginfo
->logflags
;
437 ipt_log_packet(NFPROTO_IPV4
, par
->hooknum
, skb
, par
->in
, par
->out
, &li
,
442 static bool log_tg_check(const struct xt_tgchk_param
*par
)
444 const struct ipt_log_info
*loginfo
= par
->targinfo
;
446 if (loginfo
->level
>= 8) {
447 pr_debug("LOG: level %u >= 8\n", loginfo
->level
);
450 if (loginfo
->prefix
[sizeof(loginfo
->prefix
)-1] != '\0') {
451 pr_debug("LOG: prefix term %i\n",
452 loginfo
->prefix
[sizeof(loginfo
->prefix
)-1]);
458 static struct xt_target log_tg_reg __read_mostly
= {
460 .family
= NFPROTO_IPV4
,
462 .targetsize
= sizeof(struct ipt_log_info
),
463 .checkentry
= log_tg_check
,
467 static struct nf_logger ipt_log_logger __read_mostly
= {
469 .logfn
= &ipt_log_packet
,
473 static int __init
log_tg_init(void)
477 ret
= xt_register_target(&log_tg_reg
);
480 nf_log_register(NFPROTO_IPV4
, &ipt_log_logger
);
484 static void __exit
log_tg_exit(void)
486 nf_log_unregister(&ipt_log_logger
);
487 xt_unregister_target(&log_tg_reg
);
490 module_init(log_tg_init
);
491 module_exit(log_tg_exit
);