xref: /openbmc/linux/net/ipv4/tcp_diag.c (revision 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2)
1 /*
2  * tcp_diag.c	Module for monitoring TCP sockets.
3  *
4  * Version:	$Id: tcp_diag.c,v 1.3 2002/02/01 22:01:04 davem Exp $
5  *
6  * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
7  *
8  *	This program is free software; you can redistribute it and/or
9  *      modify it under the terms of the GNU General Public License
10  *      as published by the Free Software Foundation; either version
11  *      2 of the License, or (at your option) any later version.
12  */
13 
14 #include <linux/config.h>
15 #include <linux/module.h>
16 #include <linux/types.h>
17 #include <linux/fcntl.h>
18 #include <linux/random.h>
19 #include <linux/cache.h>
20 #include <linux/init.h>
21 #include <linux/time.h>
22 
23 #include <net/icmp.h>
24 #include <net/tcp.h>
25 #include <net/ipv6.h>
26 #include <net/inet_common.h>
27 
28 #include <linux/inet.h>
29 #include <linux/stddef.h>
30 
31 #include <linux/tcp_diag.h>
32 
33 struct tcpdiag_entry
34 {
35 	u32 *saddr;
36 	u32 *daddr;
37 	u16 sport;
38 	u16 dport;
39 	u16 family;
40 	u16 userlocks;
41 };
42 
43 static struct sock *tcpnl;
44 
45 
46 #define TCPDIAG_PUT(skb, attrtype, attrlen) \
47 ({ int rtalen = RTA_LENGTH(attrlen);        \
48    struct rtattr *rta;                      \
49    if (skb_tailroom(skb) < RTA_ALIGN(rtalen)) goto nlmsg_failure; \
50    rta = (void*)__skb_put(skb, RTA_ALIGN(rtalen)); \
51    rta->rta_type = attrtype;                \
52    rta->rta_len = rtalen;                   \
53    RTA_DATA(rta); })
54 
55 static int tcpdiag_fill(struct sk_buff *skb, struct sock *sk,
56 			int ext, u32 pid, u32 seq, u16 nlmsg_flags)
57 {
58 	struct inet_sock *inet = inet_sk(sk);
59 	struct tcp_sock *tp = tcp_sk(sk);
60 	struct tcpdiagmsg *r;
61 	struct nlmsghdr  *nlh;
62 	struct tcp_info  *info = NULL;
63 	struct tcpdiag_meminfo  *minfo = NULL;
64 	struct tcpvegas_info *vinfo = NULL;
65 	unsigned char	 *b = skb->tail;
66 
67 	nlh = NLMSG_PUT(skb, pid, seq, TCPDIAG_GETSOCK, sizeof(*r));
68 	nlh->nlmsg_flags = nlmsg_flags;
69 	r = NLMSG_DATA(nlh);
70 	if (sk->sk_state != TCP_TIME_WAIT) {
71 		if (ext & (1<<(TCPDIAG_MEMINFO-1)))
72 			minfo = TCPDIAG_PUT(skb, TCPDIAG_MEMINFO, sizeof(*minfo));
73 		if (ext & (1<<(TCPDIAG_INFO-1)))
74 			info = TCPDIAG_PUT(skb, TCPDIAG_INFO, sizeof(*info));
75 
76 		if ((tcp_is_westwood(tp) || tcp_is_vegas(tp))
77 		    && (ext & (1<<(TCPDIAG_VEGASINFO-1))))
78 			vinfo = TCPDIAG_PUT(skb, TCPDIAG_VEGASINFO, sizeof(*vinfo));
79 	}
80 	r->tcpdiag_family = sk->sk_family;
81 	r->tcpdiag_state = sk->sk_state;
82 	r->tcpdiag_timer = 0;
83 	r->tcpdiag_retrans = 0;
84 
85 	r->id.tcpdiag_if = sk->sk_bound_dev_if;
86 	r->id.tcpdiag_cookie[0] = (u32)(unsigned long)sk;
87 	r->id.tcpdiag_cookie[1] = (u32)(((unsigned long)sk >> 31) >> 1);
88 
89 	if (r->tcpdiag_state == TCP_TIME_WAIT) {
90 		struct tcp_tw_bucket *tw = (struct tcp_tw_bucket*)sk;
91 		long tmo = tw->tw_ttd - jiffies;
92 		if (tmo < 0)
93 			tmo = 0;
94 
95 		r->id.tcpdiag_sport = tw->tw_sport;
96 		r->id.tcpdiag_dport = tw->tw_dport;
97 		r->id.tcpdiag_src[0] = tw->tw_rcv_saddr;
98 		r->id.tcpdiag_dst[0] = tw->tw_daddr;
99 		r->tcpdiag_state = tw->tw_substate;
100 		r->tcpdiag_timer = 3;
101 		r->tcpdiag_expires = (tmo*1000+HZ-1)/HZ;
102 		r->tcpdiag_rqueue = 0;
103 		r->tcpdiag_wqueue = 0;
104 		r->tcpdiag_uid = 0;
105 		r->tcpdiag_inode = 0;
106 #ifdef CONFIG_IP_TCPDIAG_IPV6
107 		if (r->tcpdiag_family == AF_INET6) {
108 			ipv6_addr_copy((struct in6_addr *)r->id.tcpdiag_src,
109 				       &tw->tw_v6_rcv_saddr);
110 			ipv6_addr_copy((struct in6_addr *)r->id.tcpdiag_dst,
111 				       &tw->tw_v6_daddr);
112 		}
113 #endif
114 		nlh->nlmsg_len = skb->tail - b;
115 		return skb->len;
116 	}
117 
118 	r->id.tcpdiag_sport = inet->sport;
119 	r->id.tcpdiag_dport = inet->dport;
120 	r->id.tcpdiag_src[0] = inet->rcv_saddr;
121 	r->id.tcpdiag_dst[0] = inet->daddr;
122 
123 #ifdef CONFIG_IP_TCPDIAG_IPV6
124 	if (r->tcpdiag_family == AF_INET6) {
125 		struct ipv6_pinfo *np = inet6_sk(sk);
126 
127 		ipv6_addr_copy((struct in6_addr *)r->id.tcpdiag_src,
128 			       &np->rcv_saddr);
129 		ipv6_addr_copy((struct in6_addr *)r->id.tcpdiag_dst,
130 			       &np->daddr);
131 	}
132 #endif
133 
134 #define EXPIRES_IN_MS(tmo)  ((tmo-jiffies)*1000+HZ-1)/HZ
135 
136 	if (tp->pending == TCP_TIME_RETRANS) {
137 		r->tcpdiag_timer = 1;
138 		r->tcpdiag_retrans = tp->retransmits;
139 		r->tcpdiag_expires = EXPIRES_IN_MS(tp->timeout);
140 	} else if (tp->pending == TCP_TIME_PROBE0) {
141 		r->tcpdiag_timer = 4;
142 		r->tcpdiag_retrans = tp->probes_out;
143 		r->tcpdiag_expires = EXPIRES_IN_MS(tp->timeout);
144 	} else if (timer_pending(&sk->sk_timer)) {
145 		r->tcpdiag_timer = 2;
146 		r->tcpdiag_retrans = tp->probes_out;
147 		r->tcpdiag_expires = EXPIRES_IN_MS(sk->sk_timer.expires);
148 	} else {
149 		r->tcpdiag_timer = 0;
150 		r->tcpdiag_expires = 0;
151 	}
152 #undef EXPIRES_IN_MS
153 
154 	r->tcpdiag_rqueue = tp->rcv_nxt - tp->copied_seq;
155 	r->tcpdiag_wqueue = tp->write_seq - tp->snd_una;
156 	r->tcpdiag_uid = sock_i_uid(sk);
157 	r->tcpdiag_inode = sock_i_ino(sk);
158 
159 	if (minfo) {
160 		minfo->tcpdiag_rmem = atomic_read(&sk->sk_rmem_alloc);
161 		minfo->tcpdiag_wmem = sk->sk_wmem_queued;
162 		minfo->tcpdiag_fmem = sk->sk_forward_alloc;
163 		minfo->tcpdiag_tmem = atomic_read(&sk->sk_wmem_alloc);
164 	}
165 
166 	if (info)
167 		tcp_get_info(sk, info);
168 
169 	if (vinfo) {
170 		if (tcp_is_vegas(tp)) {
171 			vinfo->tcpv_enabled = tp->vegas.doing_vegas_now;
172 			vinfo->tcpv_rttcnt = tp->vegas.cntRTT;
173 			vinfo->tcpv_rtt = jiffies_to_usecs(tp->vegas.baseRTT);
174 			vinfo->tcpv_minrtt = jiffies_to_usecs(tp->vegas.minRTT);
175 		} else {
176 			vinfo->tcpv_enabled = 0;
177 			vinfo->tcpv_rttcnt = 0;
178 			vinfo->tcpv_rtt = jiffies_to_usecs(tp->westwood.rtt);
179 			vinfo->tcpv_minrtt = jiffies_to_usecs(tp->westwood.rtt_min);
180 		}
181 	}
182 
183 	nlh->nlmsg_len = skb->tail - b;
184 	return skb->len;
185 
186 nlmsg_failure:
187 	skb_trim(skb, b - skb->data);
188 	return -1;
189 }
190 
191 extern struct sock *tcp_v4_lookup(u32 saddr, u16 sport, u32 daddr, u16 dport,
192 				  int dif);
193 #ifdef CONFIG_IP_TCPDIAG_IPV6
194 extern struct sock *tcp_v6_lookup(struct in6_addr *saddr, u16 sport,
195 				  struct in6_addr *daddr, u16 dport,
196 				  int dif);
197 #else
198 static inline struct sock *tcp_v6_lookup(struct in6_addr *saddr, u16 sport,
199 					 struct in6_addr *daddr, u16 dport,
200 					 int dif)
201 {
202 	return NULL;
203 }
204 #endif
205 
206 static int tcpdiag_get_exact(struct sk_buff *in_skb, const struct nlmsghdr *nlh)
207 {
208 	int err;
209 	struct sock *sk;
210 	struct tcpdiagreq *req = NLMSG_DATA(nlh);
211 	struct sk_buff *rep;
212 
213 	if (req->tcpdiag_family == AF_INET) {
214 		sk = tcp_v4_lookup(req->id.tcpdiag_dst[0], req->id.tcpdiag_dport,
215 				   req->id.tcpdiag_src[0], req->id.tcpdiag_sport,
216 				   req->id.tcpdiag_if);
217 	}
218 #ifdef CONFIG_IP_TCPDIAG_IPV6
219 	else if (req->tcpdiag_family == AF_INET6) {
220 		sk = tcp_v6_lookup((struct in6_addr*)req->id.tcpdiag_dst, req->id.tcpdiag_dport,
221 				   (struct in6_addr*)req->id.tcpdiag_src, req->id.tcpdiag_sport,
222 				   req->id.tcpdiag_if);
223 	}
224 #endif
225 	else {
226 		return -EINVAL;
227 	}
228 
229 	if (sk == NULL)
230 		return -ENOENT;
231 
232 	err = -ESTALE;
233 	if ((req->id.tcpdiag_cookie[0] != TCPDIAG_NOCOOKIE ||
234 	     req->id.tcpdiag_cookie[1] != TCPDIAG_NOCOOKIE) &&
235 	    ((u32)(unsigned long)sk != req->id.tcpdiag_cookie[0] ||
236 	     (u32)((((unsigned long)sk) >> 31) >> 1) != req->id.tcpdiag_cookie[1]))
237 		goto out;
238 
239 	err = -ENOMEM;
240 	rep = alloc_skb(NLMSG_SPACE(sizeof(struct tcpdiagmsg)+
241 				    sizeof(struct tcpdiag_meminfo)+
242 				    sizeof(struct tcp_info)+64), GFP_KERNEL);
243 	if (!rep)
244 		goto out;
245 
246 	if (tcpdiag_fill(rep, sk, req->tcpdiag_ext,
247 			 NETLINK_CB(in_skb).pid,
248 			 nlh->nlmsg_seq, 0) <= 0)
249 		BUG();
250 
251 	err = netlink_unicast(tcpnl, rep, NETLINK_CB(in_skb).pid, MSG_DONTWAIT);
252 	if (err > 0)
253 		err = 0;
254 
255 out:
256 	if (sk) {
257 		if (sk->sk_state == TCP_TIME_WAIT)
258 			tcp_tw_put((struct tcp_tw_bucket*)sk);
259 		else
260 			sock_put(sk);
261 	}
262 	return err;
263 }
264 
265 static int bitstring_match(const u32 *a1, const u32 *a2, int bits)
266 {
267 	int words = bits >> 5;
268 
269 	bits &= 0x1f;
270 
271 	if (words) {
272 		if (memcmp(a1, a2, words << 2))
273 			return 0;
274 	}
275 	if (bits) {
276 		__u32 w1, w2;
277 		__u32 mask;
278 
279 		w1 = a1[words];
280 		w2 = a2[words];
281 
282 		mask = htonl((0xffffffff) << (32 - bits));
283 
284 		if ((w1 ^ w2) & mask)
285 			return 0;
286 	}
287 
288 	return 1;
289 }
290 
291 
292 static int tcpdiag_bc_run(const void *bc, int len,
293 			  const struct tcpdiag_entry *entry)
294 {
295 	while (len > 0) {
296 		int yes = 1;
297 		const struct tcpdiag_bc_op *op = bc;
298 
299 		switch (op->code) {
300 		case TCPDIAG_BC_NOP:
301 			break;
302 		case TCPDIAG_BC_JMP:
303 			yes = 0;
304 			break;
305 		case TCPDIAG_BC_S_GE:
306 			yes = entry->sport >= op[1].no;
307 			break;
308 		case TCPDIAG_BC_S_LE:
309 			yes = entry->dport <= op[1].no;
310 			break;
311 		case TCPDIAG_BC_D_GE:
312 			yes = entry->dport >= op[1].no;
313 			break;
314 		case TCPDIAG_BC_D_LE:
315 			yes = entry->dport <= op[1].no;
316 			break;
317 		case TCPDIAG_BC_AUTO:
318 			yes = !(entry->userlocks & SOCK_BINDPORT_LOCK);
319 			break;
320 		case TCPDIAG_BC_S_COND:
321 		case TCPDIAG_BC_D_COND:
322 		{
323 			struct tcpdiag_hostcond *cond = (struct tcpdiag_hostcond*)(op+1);
324 			u32 *addr;
325 
326 			if (cond->port != -1 &&
327 			    cond->port != (op->code == TCPDIAG_BC_S_COND ?
328 					     entry->sport : entry->dport)) {
329 				yes = 0;
330 				break;
331 			}
332 
333 			if (cond->prefix_len == 0)
334 				break;
335 
336 			if (op->code == TCPDIAG_BC_S_COND)
337 				addr = entry->saddr;
338 			else
339 				addr = entry->daddr;
340 
341 			if (bitstring_match(addr, cond->addr, cond->prefix_len))
342 				break;
343 			if (entry->family == AF_INET6 &&
344 			    cond->family == AF_INET) {
345 				if (addr[0] == 0 && addr[1] == 0 &&
346 				    addr[2] == htonl(0xffff) &&
347 				    bitstring_match(addr+3, cond->addr, cond->prefix_len))
348 					break;
349 			}
350 			yes = 0;
351 			break;
352 		}
353 		}
354 
355 		if (yes) {
356 			len -= op->yes;
357 			bc += op->yes;
358 		} else {
359 			len -= op->no;
360 			bc += op->no;
361 		}
362 	}
363 	return (len == 0);
364 }
365 
366 static int valid_cc(const void *bc, int len, int cc)
367 {
368 	while (len >= 0) {
369 		const struct tcpdiag_bc_op *op = bc;
370 
371 		if (cc > len)
372 			return 0;
373 		if (cc == len)
374 			return 1;
375 		if (op->yes < 4)
376 			return 0;
377 		len -= op->yes;
378 		bc  += op->yes;
379 	}
380 	return 0;
381 }
382 
383 static int tcpdiag_bc_audit(const void *bytecode, int bytecode_len)
384 {
385 	const unsigned char *bc = bytecode;
386 	int  len = bytecode_len;
387 
388 	while (len > 0) {
389 		struct tcpdiag_bc_op *op = (struct tcpdiag_bc_op*)bc;
390 
391 //printk("BC: %d %d %d {%d} / %d\n", op->code, op->yes, op->no, op[1].no, len);
392 		switch (op->code) {
393 		case TCPDIAG_BC_AUTO:
394 		case TCPDIAG_BC_S_COND:
395 		case TCPDIAG_BC_D_COND:
396 		case TCPDIAG_BC_S_GE:
397 		case TCPDIAG_BC_S_LE:
398 		case TCPDIAG_BC_D_GE:
399 		case TCPDIAG_BC_D_LE:
400 			if (op->yes < 4 || op->yes > len+4)
401 				return -EINVAL;
402 		case TCPDIAG_BC_JMP:
403 			if (op->no < 4 || op->no > len+4)
404 				return -EINVAL;
405 			if (op->no < len &&
406 			    !valid_cc(bytecode, bytecode_len, len-op->no))
407 				return -EINVAL;
408 			break;
409 		case TCPDIAG_BC_NOP:
410 			if (op->yes < 4 || op->yes > len+4)
411 				return -EINVAL;
412 			break;
413 		default:
414 			return -EINVAL;
415 		}
416 		bc += op->yes;
417 		len -= op->yes;
418 	}
419 	return len == 0 ? 0 : -EINVAL;
420 }
421 
422 static int tcpdiag_dump_sock(struct sk_buff *skb, struct sock *sk,
423 			     struct netlink_callback *cb)
424 {
425 	struct tcpdiagreq *r = NLMSG_DATA(cb->nlh);
426 
427 	if (cb->nlh->nlmsg_len > 4 + NLMSG_SPACE(sizeof(*r))) {
428 		struct tcpdiag_entry entry;
429 		struct rtattr *bc = (struct rtattr *)(r + 1);
430 		struct inet_sock *inet = inet_sk(sk);
431 
432 		entry.family = sk->sk_family;
433 #ifdef CONFIG_IP_TCPDIAG_IPV6
434 		if (entry.family == AF_INET6) {
435 			struct ipv6_pinfo *np = inet6_sk(sk);
436 
437 			entry.saddr = np->rcv_saddr.s6_addr32;
438 			entry.daddr = np->daddr.s6_addr32;
439 		} else
440 #endif
441 		{
442 			entry.saddr = &inet->rcv_saddr;
443 			entry.daddr = &inet->daddr;
444 		}
445 		entry.sport = inet->num;
446 		entry.dport = ntohs(inet->dport);
447 		entry.userlocks = sk->sk_userlocks;
448 
449 		if (!tcpdiag_bc_run(RTA_DATA(bc), RTA_PAYLOAD(bc), &entry))
450 			return 0;
451 	}
452 
453 	return tcpdiag_fill(skb, sk, r->tcpdiag_ext, NETLINK_CB(cb->skb).pid,
454 			    cb->nlh->nlmsg_seq, NLM_F_MULTI);
455 }
456 
457 static int tcpdiag_fill_req(struct sk_buff *skb, struct sock *sk,
458 			    struct open_request *req,
459 			    u32 pid, u32 seq)
460 {
461 	struct inet_sock *inet = inet_sk(sk);
462 	unsigned char *b = skb->tail;
463 	struct tcpdiagmsg *r;
464 	struct nlmsghdr *nlh;
465 	long tmo;
466 
467 	nlh = NLMSG_PUT(skb, pid, seq, TCPDIAG_GETSOCK, sizeof(*r));
468 	nlh->nlmsg_flags = NLM_F_MULTI;
469 	r = NLMSG_DATA(nlh);
470 
471 	r->tcpdiag_family = sk->sk_family;
472 	r->tcpdiag_state = TCP_SYN_RECV;
473 	r->tcpdiag_timer = 1;
474 	r->tcpdiag_retrans = req->retrans;
475 
476 	r->id.tcpdiag_if = sk->sk_bound_dev_if;
477 	r->id.tcpdiag_cookie[0] = (u32)(unsigned long)req;
478 	r->id.tcpdiag_cookie[1] = (u32)(((unsigned long)req >> 31) >> 1);
479 
480 	tmo = req->expires - jiffies;
481 	if (tmo < 0)
482 		tmo = 0;
483 
484 	r->id.tcpdiag_sport = inet->sport;
485 	r->id.tcpdiag_dport = req->rmt_port;
486 	r->id.tcpdiag_src[0] = req->af.v4_req.loc_addr;
487 	r->id.tcpdiag_dst[0] = req->af.v4_req.rmt_addr;
488 	r->tcpdiag_expires = jiffies_to_msecs(tmo),
489 	r->tcpdiag_rqueue = 0;
490 	r->tcpdiag_wqueue = 0;
491 	r->tcpdiag_uid = sock_i_uid(sk);
492 	r->tcpdiag_inode = 0;
493 #ifdef CONFIG_IP_TCPDIAG_IPV6
494 	if (r->tcpdiag_family == AF_INET6) {
495 		ipv6_addr_copy((struct in6_addr *)r->id.tcpdiag_src,
496 			       &req->af.v6_req.loc_addr);
497 		ipv6_addr_copy((struct in6_addr *)r->id.tcpdiag_dst,
498 			       &req->af.v6_req.rmt_addr);
499 	}
500 #endif
501 	nlh->nlmsg_len = skb->tail - b;
502 
503 	return skb->len;
504 
505 nlmsg_failure:
506 	skb_trim(skb, b - skb->data);
507 	return -1;
508 }
509 
510 static int tcpdiag_dump_reqs(struct sk_buff *skb, struct sock *sk,
511 			     struct netlink_callback *cb)
512 {
513 	struct tcpdiag_entry entry;
514 	struct tcpdiagreq *r = NLMSG_DATA(cb->nlh);
515 	struct tcp_sock *tp = tcp_sk(sk);
516 	struct tcp_listen_opt *lopt;
517 	struct rtattr *bc = NULL;
518 	struct inet_sock *inet = inet_sk(sk);
519 	int j, s_j;
520 	int reqnum, s_reqnum;
521 	int err = 0;
522 
523 	s_j = cb->args[3];
524 	s_reqnum = cb->args[4];
525 
526 	if (s_j > 0)
527 		s_j--;
528 
529 	entry.family = sk->sk_family;
530 
531 	read_lock_bh(&tp->syn_wait_lock);
532 
533 	lopt = tp->listen_opt;
534 	if (!lopt || !lopt->qlen)
535 		goto out;
536 
537 	if (cb->nlh->nlmsg_len > 4 + NLMSG_SPACE(sizeof(*r))) {
538 		bc = (struct rtattr *)(r + 1);
539 		entry.sport = inet->num;
540 		entry.userlocks = sk->sk_userlocks;
541 	}
542 
543 	for (j = s_j; j < TCP_SYNQ_HSIZE; j++) {
544 		struct open_request *req, *head = lopt->syn_table[j];
545 
546 		reqnum = 0;
547 		for (req = head; req; reqnum++, req = req->dl_next) {
548 			if (reqnum < s_reqnum)
549 				continue;
550 			if (r->id.tcpdiag_dport != req->rmt_port &&
551 			    r->id.tcpdiag_dport)
552 				continue;
553 
554 			if (bc) {
555 				entry.saddr =
556 #ifdef CONFIG_IP_TCPDIAG_IPV6
557 					(entry.family == AF_INET6) ?
558 					req->af.v6_req.loc_addr.s6_addr32 :
559 #endif
560 					&req->af.v4_req.loc_addr;
561 				entry.daddr =
562 #ifdef CONFIG_IP_TCPDIAG_IPV6
563 					(entry.family == AF_INET6) ?
564 					req->af.v6_req.rmt_addr.s6_addr32 :
565 #endif
566 					&req->af.v4_req.rmt_addr;
567 				entry.dport = ntohs(req->rmt_port);
568 
569 				if (!tcpdiag_bc_run(RTA_DATA(bc),
570 						    RTA_PAYLOAD(bc), &entry))
571 					continue;
572 			}
573 
574 			err = tcpdiag_fill_req(skb, sk, req,
575 					       NETLINK_CB(cb->skb).pid,
576 					       cb->nlh->nlmsg_seq);
577 			if (err < 0) {
578 				cb->args[3] = j + 1;
579 				cb->args[4] = reqnum;
580 				goto out;
581 			}
582 		}
583 
584 		s_reqnum = 0;
585 	}
586 
587 out:
588 	read_unlock_bh(&tp->syn_wait_lock);
589 
590 	return err;
591 }
592 
593 static int tcpdiag_dump(struct sk_buff *skb, struct netlink_callback *cb)
594 {
595 	int i, num;
596 	int s_i, s_num;
597 	struct tcpdiagreq *r = NLMSG_DATA(cb->nlh);
598 
599 	s_i = cb->args[1];
600 	s_num = num = cb->args[2];
601 
602 	if (cb->args[0] == 0) {
603 		if (!(r->tcpdiag_states&(TCPF_LISTEN|TCPF_SYN_RECV)))
604 			goto skip_listen_ht;
605 		tcp_listen_lock();
606 		for (i = s_i; i < TCP_LHTABLE_SIZE; i++) {
607 			struct sock *sk;
608 			struct hlist_node *node;
609 
610 			num = 0;
611 			sk_for_each(sk, node, &tcp_listening_hash[i]) {
612 				struct inet_sock *inet = inet_sk(sk);
613 
614 				if (num < s_num) {
615 					num++;
616 					continue;
617 				}
618 
619 				if (r->id.tcpdiag_sport != inet->sport &&
620 				    r->id.tcpdiag_sport)
621 					goto next_listen;
622 
623 				if (!(r->tcpdiag_states&TCPF_LISTEN) ||
624 				    r->id.tcpdiag_dport ||
625 				    cb->args[3] > 0)
626 					goto syn_recv;
627 
628 				if (tcpdiag_dump_sock(skb, sk, cb) < 0) {
629 					tcp_listen_unlock();
630 					goto done;
631 				}
632 
633 syn_recv:
634 				if (!(r->tcpdiag_states&TCPF_SYN_RECV))
635 					goto next_listen;
636 
637 				if (tcpdiag_dump_reqs(skb, sk, cb) < 0) {
638 					tcp_listen_unlock();
639 					goto done;
640 				}
641 
642 next_listen:
643 				cb->args[3] = 0;
644 				cb->args[4] = 0;
645 				++num;
646 			}
647 
648 			s_num = 0;
649 			cb->args[3] = 0;
650 			cb->args[4] = 0;
651 		}
652 		tcp_listen_unlock();
653 skip_listen_ht:
654 		cb->args[0] = 1;
655 		s_i = num = s_num = 0;
656 	}
657 
658 	if (!(r->tcpdiag_states&~(TCPF_LISTEN|TCPF_SYN_RECV)))
659 		return skb->len;
660 
661 	for (i = s_i; i < tcp_ehash_size; i++) {
662 		struct tcp_ehash_bucket *head = &tcp_ehash[i];
663 		struct sock *sk;
664 		struct hlist_node *node;
665 
666 		if (i > s_i)
667 			s_num = 0;
668 
669 		read_lock_bh(&head->lock);
670 
671 		num = 0;
672 		sk_for_each(sk, node, &head->chain) {
673 			struct inet_sock *inet = inet_sk(sk);
674 
675 			if (num < s_num)
676 				goto next_normal;
677 			if (!(r->tcpdiag_states & (1 << sk->sk_state)))
678 				goto next_normal;
679 			if (r->id.tcpdiag_sport != inet->sport &&
680 			    r->id.tcpdiag_sport)
681 				goto next_normal;
682 			if (r->id.tcpdiag_dport != inet->dport && r->id.tcpdiag_dport)
683 				goto next_normal;
684 			if (tcpdiag_dump_sock(skb, sk, cb) < 0) {
685 				read_unlock_bh(&head->lock);
686 				goto done;
687 			}
688 next_normal:
689 			++num;
690 		}
691 
692 		if (r->tcpdiag_states&TCPF_TIME_WAIT) {
693 			sk_for_each(sk, node,
694 				    &tcp_ehash[i + tcp_ehash_size].chain) {
695 				struct inet_sock *inet = inet_sk(sk);
696 
697 				if (num < s_num)
698 					goto next_dying;
699 				if (r->id.tcpdiag_sport != inet->sport &&
700 				    r->id.tcpdiag_sport)
701 					goto next_dying;
702 				if (r->id.tcpdiag_dport != inet->dport &&
703 				    r->id.tcpdiag_dport)
704 					goto next_dying;
705 				if (tcpdiag_dump_sock(skb, sk, cb) < 0) {
706 					read_unlock_bh(&head->lock);
707 					goto done;
708 				}
709 next_dying:
710 				++num;
711 			}
712 		}
713 		read_unlock_bh(&head->lock);
714 	}
715 
716 done:
717 	cb->args[1] = i;
718 	cb->args[2] = num;
719 	return skb->len;
720 }
721 
722 static int tcpdiag_dump_done(struct netlink_callback *cb)
723 {
724 	return 0;
725 }
726 
727 
728 static __inline__ int
729 tcpdiag_rcv_msg(struct sk_buff *skb, struct nlmsghdr *nlh)
730 {
731 	if (!(nlh->nlmsg_flags&NLM_F_REQUEST))
732 		return 0;
733 
734 	if (nlh->nlmsg_type != TCPDIAG_GETSOCK)
735 		goto err_inval;
736 
737 	if (NLMSG_LENGTH(sizeof(struct tcpdiagreq)) > skb->len)
738 		goto err_inval;
739 
740 	if (nlh->nlmsg_flags&NLM_F_DUMP) {
741 		if (nlh->nlmsg_len > 4 + NLMSG_SPACE(sizeof(struct tcpdiagreq))) {
742 			struct rtattr *rta = (struct rtattr*)(NLMSG_DATA(nlh) + sizeof(struct tcpdiagreq));
743 			if (rta->rta_type != TCPDIAG_REQ_BYTECODE ||
744 			    rta->rta_len < 8 ||
745 			    rta->rta_len > nlh->nlmsg_len - NLMSG_SPACE(sizeof(struct tcpdiagreq)))
746 				goto err_inval;
747 			if (tcpdiag_bc_audit(RTA_DATA(rta), RTA_PAYLOAD(rta)))
748 				goto err_inval;
749 		}
750 		return netlink_dump_start(tcpnl, skb, nlh,
751 					  tcpdiag_dump,
752 					  tcpdiag_dump_done);
753 	} else {
754 		return tcpdiag_get_exact(skb, nlh);
755 	}
756 
757 err_inval:
758 	return -EINVAL;
759 }
760 
761 
762 static inline void tcpdiag_rcv_skb(struct sk_buff *skb)
763 {
764 	int err;
765 	struct nlmsghdr * nlh;
766 
767 	if (skb->len >= NLMSG_SPACE(0)) {
768 		nlh = (struct nlmsghdr *)skb->data;
769 		if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len)
770 			return;
771 		err = tcpdiag_rcv_msg(skb, nlh);
772 		if (err || nlh->nlmsg_flags & NLM_F_ACK)
773 			netlink_ack(skb, nlh, err);
774 	}
775 }
776 
777 static void tcpdiag_rcv(struct sock *sk, int len)
778 {
779 	struct sk_buff *skb;
780 
781 	while ((skb = skb_dequeue(&sk->sk_receive_queue)) != NULL) {
782 		tcpdiag_rcv_skb(skb);
783 		kfree_skb(skb);
784 	}
785 }
786 
787 static int __init tcpdiag_init(void)
788 {
789 	tcpnl = netlink_kernel_create(NETLINK_TCPDIAG, tcpdiag_rcv);
790 	if (tcpnl == NULL)
791 		return -ENOMEM;
792 	return 0;
793 }
794 
795 static void __exit tcpdiag_exit(void)
796 {
797 	sock_release(tcpnl->sk_socket);
798 }
799 
800 module_init(tcpdiag_init);
801 module_exit(tcpdiag_exit);
802 MODULE_LICENSE("GPL");
803