1/*
2 * This is a module which is used for logging packets.
3 */
4#include <linux/module.h>
5#include <linux/skbuff.h>
6#include <linux/ip.h>
7#include <linux/spinlock.h>
8#include <linux/icmpv6.h>
9#include <net/udp.h>
10#include <net/tcp.h>
11#include <net/ipv6.h>
12#include <linux/netfilter_ipv6/ip6_tables.h>
13
14MODULE_AUTHOR("Jan Rekorajski <baggins@pld.org.pl>");
15MODULE_DESCRIPTION("IP6 tables LOG target module");
16MODULE_LICENSE("GPL");
17
18struct in_device;
19#include <net/route.h>
20#include <linux/netfilter_ipv6/ip6t_LOG.h>
21
22#define DEBUGP(format, args...)
23
24#define NIP6(addr) \
25	ntohs((addr).s6_addr16[0]), \
26	ntohs((addr).s6_addr16[1]), \
27	ntohs((addr).s6_addr16[2]), \
28	ntohs((addr).s6_addr16[3]), \
29	ntohs((addr).s6_addr16[4]), \
30	ntohs((addr).s6_addr16[5]), \
31	ntohs((addr).s6_addr16[6]), \
32	ntohs((addr).s6_addr16[7])
33
34struct esphdr {
35	__u32   spi;
36};
37
38/* Use lock to serialize, so printks don't overlap */
39static spinlock_t log_lock = SPIN_LOCK_UNLOCKED;
40
41/* takes in current header and pointer to the header */
42/* if another header exists, sets hdrptr to the next header
43   and returns the new header value, else returns 0 */
44static u_int8_t ip6_nexthdr(u_int8_t currenthdr, u_int8_t **hdrptr)
45{
46	u_int8_t hdrlen, nexthdr = 0;
47
48	switch(currenthdr){
49		case IPPROTO_AH:
50		/* whoever decided to do the length of AUTH for ipv6
51		in 32bit units unlike other headers should be beaten...
52		repeatedly...with a large stick...no, an even LARGER
53		stick...no, you're still not thinking big enough */
54			nexthdr = **hdrptr;
55			hdrlen = *hdrptr[1] * 4 + 8;
56			*hdrptr = *hdrptr + hdrlen;
57			break;
58		/*stupid rfc2402 */
59		case IPPROTO_DSTOPTS:
60		case IPPROTO_ROUTING:
61		case IPPROTO_HOPOPTS:
62			nexthdr = **hdrptr;
63			hdrlen = *hdrptr[1] * 8 + 8;
64			*hdrptr = *hdrptr + hdrlen;
65			break;
66		case IPPROTO_FRAGMENT:
67			nexthdr = **hdrptr;
68			*hdrptr = *hdrptr + 8;
69			break;
70	}
71	return nexthdr;
72
73}
74
75/* One level of recursion won't kill us */
76static void dump_packet(const struct ip6t_log_info *info,
77			struct ipv6hdr *ipv6h, int recurse)
78{
79	u_int8_t currenthdr = ipv6h->nexthdr;
80	u_int8_t *hdrptr;
81	int fragment;
82
83	/* Max length: 88 "SRC=0000.0000.0000.0000.0000.0000.0000.0000 DST=0000.0000.0000.0000.0000.0000.0000.0000" */
84	printk("SRC=%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x ", NIP6(ipv6h->saddr));
85	printk("DST=%04x:%04x:%04x:%04x:%04x:%04x:%04x:%04x ", NIP6(ipv6h->daddr));
86
87	/* Max length: 44 "LEN=65535 TC=255 HOPLIMIT=255 FLOWLBL=FFFFF " */
88	printk("LEN=%u TC=%u HOPLIMIT=%u FLOWLBL=%u ",
89	       ntohs(ipv6h->payload_len) + sizeof(struct ipv6hdr),
90	       (ntohl(*(u_int32_t *)ipv6h) & 0x0ff00000) >> 20,
91	       ipv6h->hop_limit,
92	       (ntohl(*(u_int32_t *)ipv6h) & 0x000fffff));
93
94	fragment = 0;
95	hdrptr = (u_int8_t *)(ipv6h + 1);
96	while (currenthdr) {
97		if ((currenthdr == IPPROTO_TCP) ||
98		    (currenthdr == IPPROTO_UDP) ||
99		    (currenthdr == IPPROTO_ICMPV6))
100			break;
101		/* Max length: 48 "OPT (...) " */
102		printk("OPT ( ");
103		switch (currenthdr) {
104		case IPPROTO_FRAGMENT: {
105			struct frag_hdr *fhdr = (struct frag_hdr *)hdrptr;
106
107			/* Max length: 11 "FRAG:65535 " */
108			printk("FRAG:%u ", ntohs(fhdr->frag_off) & 0xFFF8);
109
110			/* Max length: 11 "INCOMPLETE " */
111			if (fhdr->frag_off & htons(0x0001))
112				printk("INCOMPLETE ");
113
114			printk("ID:%08x ", fhdr->identification);
115
116			if (ntohs(fhdr->frag_off) & 0xFFF8)
117				fragment = 1;
118
119			break;
120		}
121		case IPPROTO_DSTOPTS:
122		case IPPROTO_ROUTING:
123		case IPPROTO_HOPOPTS:
124			break;
125		/* Max Length */
126		case IPPROTO_AH:
127		case IPPROTO_ESP:
128			if (info->logflags & IP6T_LOG_IPOPT) {
129				struct esphdr *esph = (struct esphdr *)hdrptr;
130				int esp = (currenthdr == IPPROTO_ESP);
131
132				/* Max length: 4 "ESP " */
133				printk("%s ",esp ? "ESP" : "AH");
134
135				/* Length: 15 "SPI=0xF1234567 " */
136				printk("SPI=0x%x ", ntohl(esph->spi) );
137				break;
138			}
139		default:
140			break;
141		}
142		printk(") ");
143		currenthdr = ip6_nexthdr(currenthdr, &hdrptr);
144	}
145
146	switch (currenthdr) {
147	case IPPROTO_TCP: {
148		struct tcphdr *tcph = (struct tcphdr *)hdrptr;
149
150		/* Max length: 10 "PROTO=TCP " */
151		printk("PROTO=TCP ");
152
153		if (fragment)
154			break;
155
156		/* Max length: 20 "SPT=65535 DPT=65535 " */
157		printk("SPT=%u DPT=%u ",
158		       ntohs(tcph->source), ntohs(tcph->dest));
159		/* Max length: 30 "SEQ=4294967295 ACK=4294967295 " */
160		if (info->logflags & IP6T_LOG_TCPSEQ)
161			printk("SEQ=%u ACK=%u ",
162			       ntohl(tcph->seq), ntohl(tcph->ack_seq));
163		/* Max length: 13 "WINDOW=65535 " */
164		printk("WINDOW=%u ", ntohs(tcph->window));
165		/* Max length: 9 "RES=0x3F " */
166		printk("RES=0x%02x ", (u_int8_t)(ntohl(tcp_flag_word(tcph) & TCP_RESERVED_BITS) >> 22));
167		/* Max length: 32 "CWR ECE URG ACK PSH RST SYN FIN " */
168		if (tcph->cwr)
169			printk("CWR ");
170		if (tcph->ece)
171			printk("ECE ");
172		if (tcph->urg)
173			printk("URG ");
174		if (tcph->ack)
175			printk("ACK ");
176		if (tcph->psh)
177			printk("PSH ");
178		if (tcph->rst)
179			printk("RST ");
180		if (tcph->syn)
181			printk("SYN ");
182		if (tcph->fin)
183			printk("FIN ");
184		/* Max length: 11 "URGP=65535 " */
185		printk("URGP=%u ", ntohs(tcph->urg_ptr));
186
187		if ((info->logflags & IP6T_LOG_TCPOPT)
188		    && tcph->doff * 4 != sizeof(struct tcphdr)) {
189			unsigned int i;
190
191			/* Max length: 127 "OPT (" 15*4*2chars ") " */
192			printk("OPT (");
193			for (i =sizeof(struct tcphdr); i < tcph->doff * 4; i++)
194				printk("%02X", ((u_int8_t *)tcph)[i]);
195			printk(") ");
196		}
197		break;
198	}
199	case IPPROTO_UDP: {
200		struct udphdr *udph = (struct udphdr *)hdrptr;
201
202		/* Max length: 10 "PROTO=UDP " */
203		printk("PROTO=UDP ");
204
205		if (fragment)
206			break;
207
208		/* Max length: 20 "SPT=65535 DPT=65535 " */
209		printk("SPT=%u DPT=%u LEN=%u ",
210		       ntohs(udph->source), ntohs(udph->dest),
211		       ntohs(udph->len));
212		break;
213	}
214	case IPPROTO_ICMPV6: {
215		struct icmp6hdr *icmp6h = (struct icmp6hdr *)hdrptr;
216
217		/* Max length: 13 "PROTO=ICMPv6 " */
218		printk("PROTO=ICMPv6 ");
219
220		if (fragment)
221			break;
222
223		/* Max length: 18 "TYPE=255 CODE=255 " */
224		printk("TYPE=%u CODE=%u ", icmp6h->icmp6_type, icmp6h->icmp6_code);
225
226		switch (icmp6h->icmp6_type) {
227		case ICMPV6_ECHO_REQUEST:
228		case ICMPV6_ECHO_REPLY:
229			/* Max length: 19 "ID=65535 SEQ=65535 " */
230			printk("ID=%u SEQ=%u ",
231				ntohs(icmp6h->icmp6_identifier),
232				ntohs(icmp6h->icmp6_sequence));
233			break;
234		case ICMPV6_MGM_QUERY:
235		case ICMPV6_MGM_REPORT:
236		case ICMPV6_MGM_REDUCTION:
237			break;
238
239		case ICMPV6_PARAMPROB:
240			/* Max length: 17 "POINTER=ffffffff " */
241			printk("POINTER=%08x ", ntohl(icmp6h->icmp6_pointer));
242			/* Fall through */
243		case ICMPV6_DEST_UNREACH:
244		case ICMPV6_PKT_TOOBIG:
245		case ICMPV6_TIME_EXCEED:
246			/* Max length: 3+maxlen */
247			if (recurse) {
248				printk("[");
249				dump_packet(info, (struct ipv6hdr *)(icmp6h + 1), 0);
250				printk("] ");
251			}
252
253			/* Max length: 10 "MTU=65535 " */
254			if (icmp6h->icmp6_type == ICMPV6_PKT_TOOBIG)
255				printk("MTU=%u ", ntohl(icmp6h->icmp6_mtu));
256		}
257		break;
258	}
259	/* Max length: 10 "PROTO 255 " */
260	default:
261		printk("PROTO=%u ", currenthdr);
262	}
263}
264
265static unsigned int
266ip6t_log_target(struct sk_buff **pskb,
267		unsigned int hooknum,
268		const struct net_device *in,
269		const struct net_device *out,
270		const void *targinfo,
271		void *userinfo)
272{
273	struct ipv6hdr *ipv6h = (*pskb)->nh.ipv6h;
274	const struct ip6t_log_info *loginfo = targinfo;
275	char level_string[4] = "< >";
276
277	level_string[1] = '0' + (loginfo->level % 8);
278	spin_lock_bh(&log_lock);
279	printk(level_string);
280	printk("%sIN=%s OUT=%s ",
281		loginfo->prefix,
282		in ? in->name : "",
283		out ? out->name : "");
284	if (in && !out) {
285		/* MAC logging for input chain only. */
286		printk("MAC=");
287		if ((*pskb)->dev && (*pskb)->dev->hard_header_len && (*pskb)->mac.raw != (void*)ipv6h) {
288			if ((*pskb)->dev->type != ARPHRD_SIT){
289			  int i;
290			  unsigned char *p = (*pskb)->mac.raw;
291			  for (i = 0; i < (*pskb)->dev->hard_header_len; i++,p++)
292				printk("%02x%c", *p,
293			       		i==(*pskb)->dev->hard_header_len - 1
294			       		? ' ':':');
295			} else {
296			  int i;
297			  unsigned char *p = (*pskb)->mac.raw;
298			  if ( p - (ETH_ALEN*2+2) > (*pskb)->head ){
299			    p -= (ETH_ALEN+2);
300			    for (i = 0; i < (ETH_ALEN); i++,p++)
301				printk("%02x%s", *p,
302					i == ETH_ALEN-1 ? "->" : ":");
303			    p -= (ETH_ALEN*2);
304			    for (i = 0; i < (ETH_ALEN); i++,p++)
305				printk("%02x%c", *p,
306					i == ETH_ALEN-1 ? ' ' : ':');
307			  }
308
309			  if (((*pskb)->dev->addr_len == 4) &&
310			      (*pskb)->dev->hard_header_len > 20){
311			    printk("TUNNEL=");
312			    p = (*pskb)->mac.raw + 12;
313			    for (i = 0; i < 4; i++,p++)
314				printk("%3d%s", *p,
315					i == 3 ? "->" : ".");
316			    for (i = 0; i < 4; i++,p++)
317				printk("%3d%c", *p,
318					i == 3 ? ' ' : '.');
319			  }
320			}
321		} else
322			printk(" ");
323	}
324
325	dump_packet(loginfo, ipv6h, 1);
326	printk("\n");
327	spin_unlock_bh(&log_lock);
328
329	return IP6T_CONTINUE;
330}
331
332static int ip6t_log_checkentry(const char *tablename,
333			       const struct ip6t_entry *e,
334			       void *targinfo,
335			       unsigned int targinfosize,
336			       unsigned int hook_mask)
337{
338	const struct ip6t_log_info *loginfo = targinfo;
339
340	if (targinfosize != IP6T_ALIGN(sizeof(struct ip6t_log_info))) {
341		DEBUGP("LOG: targinfosize %u != %u\n",
342		       targinfosize, IP6T_ALIGN(sizeof(struct ip6t_log_info)));
343		return 0;
344	}
345
346	if (loginfo->level >= 8) {
347		DEBUGP("LOG: level %u >= 8\n", loginfo->level);
348		return 0;
349	}
350
351	if (loginfo->prefix[sizeof(loginfo->prefix)-1] != '\0') {
352		DEBUGP("LOG: prefix term %i\n",
353		       loginfo->prefix[sizeof(loginfo->prefix)-1]);
354		return 0;
355	}
356
357	return 1;
358}
359
360static struct ip6t_target ip6t_log_reg
361= { { NULL, NULL }, "LOG", ip6t_log_target, ip6t_log_checkentry, NULL,
362    THIS_MODULE };
363
364static int __init init(void)
365{
366	if (ip6t_register_target(&ip6t_log_reg))
367		return -EINVAL;
368
369	return 0;
370}
371
372static void __exit fini(void)
373{
374	ip6t_unregister_target(&ip6t_log_reg);
375}
376
377module_init(init);
378module_exit(fini);
379