tcp_diag.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * tcp_diag.c	Module for monitoring TCP transport protocols sockets.
  4 *
  5 * Authors:	Alexey Kuznetsov, <kuznet@ms2.inr.ac.ru>
  6 */
  7
  8#include <linux/module.h>
  9#include <linux/net.h>
 10#include <linux/sock_diag.h>
 11#include <linux/inet_diag.h>
 12
 13#include <linux/tcp.h>
 14
 15#include <net/inet_hashtables.h>
 16#include <net/inet6_hashtables.h>
 17#include <net/inet_timewait_sock.h>
 18#include <net/netlink.h>
 19#include <net/tcp.h>
 20
 21static void tcp_diag_get_info(struct sock *sk, struct inet_diag_msg *r,
 22			      void *_info)
 23{
 24	struct tcp_info *info = _info;
 25
 26	if (inet_sk_state_load(sk) == TCP_LISTEN) {
 27		r->idiag_rqueue = READ_ONCE(sk->sk_ack_backlog);
 28		r->idiag_wqueue = READ_ONCE(sk->sk_max_ack_backlog);
 29	} else if (sk->sk_type == SOCK_STREAM) {
 30		const struct tcp_sock *tp = tcp_sk(sk);
 31
 32		r->idiag_rqueue = max_t(int, READ_ONCE(tp->rcv_nxt) -
 33					     READ_ONCE(tp->copied_seq), 0);
 34		r->idiag_wqueue = READ_ONCE(tp->write_seq) - tp->snd_una;
 35	}
 36	if (info)
 37		tcp_get_info(sk, info);
 38}
 39
 40#ifdef CONFIG_TCP_MD5SIG
 41static void tcp_diag_md5sig_fill(struct tcp_diag_md5sig *info,
 42				 const struct tcp_md5sig_key *key)
 43{
 44	info->tcpm_family = key->family;
 45	info->tcpm_prefixlen = key->prefixlen;
 46	info->tcpm_keylen = key->keylen;
 47	memcpy(info->tcpm_key, key->key, key->keylen);
 48
 49	if (key->family == AF_INET)
 50		info->tcpm_addr[0] = key->addr.a4.s_addr;
 51	#if IS_ENABLED(CONFIG_IPV6)
 52	else if (key->family == AF_INET6)
 53		memcpy(&info->tcpm_addr, &key->addr.a6,
 54		       sizeof(info->tcpm_addr));
 55	#endif
 56}
 57
 58static int tcp_diag_put_md5sig(struct sk_buff *skb,
 59			       const struct tcp_md5sig_info *md5sig)
 60{
 61	const struct tcp_md5sig_key *key;
 62	struct tcp_diag_md5sig *info;
 63	struct nlattr *attr;
 64	int md5sig_count = 0;
 65
 66	hlist_for_each_entry_rcu(key, &md5sig->head, node)
 67		md5sig_count++;
 68	if (md5sig_count == 0)
 69		return 0;
 70
 71	attr = nla_reserve(skb, INET_DIAG_MD5SIG,
 72			   md5sig_count * sizeof(struct tcp_diag_md5sig));
 73	if (!attr)
 74		return -EMSGSIZE;
 75
 76	info = nla_data(attr);
 77	memset(info, 0, md5sig_count * sizeof(struct tcp_diag_md5sig));
 78	hlist_for_each_entry_rcu(key, &md5sig->head, node) {
 79		tcp_diag_md5sig_fill(info++, key);
 80		if (--md5sig_count == 0)
 81			break;
 82	}
 83
 84	return 0;
 85}
 86#endif
 87
 88static int tcp_diag_put_ulp(struct sk_buff *skb, struct sock *sk,
 89			    const struct tcp_ulp_ops *ulp_ops, bool net_admin)
 90{
 91	struct nlattr *nest;
 92	int err;
 93
 94	nest = nla_nest_start_noflag(skb, INET_DIAG_ULP_INFO);
 95	if (!nest)
 96		return -EMSGSIZE;
 97
 98	err = nla_put_string(skb, INET_ULP_INFO_NAME, ulp_ops->name);
 99	if (err)
100		goto nla_failure;
101
102	if (ulp_ops->get_info)
103		err = ulp_ops->get_info(sk, skb, net_admin);
104	if (err)
105		goto nla_failure;
106
107	nla_nest_end(skb, nest);
108	return 0;
109
110nla_failure:
111	nla_nest_cancel(skb, nest);
112	return err;
113}
114
115static int tcp_diag_get_aux(struct sock *sk, bool net_admin,
116			    struct sk_buff *skb)
117{
118	struct inet_connection_sock *icsk = inet_csk(sk);
119	const struct tcp_ulp_ops *ulp_ops;
120	int err = 0;
121
122#ifdef CONFIG_TCP_MD5SIG
123	if (net_admin) {
124		struct tcp_md5sig_info *md5sig;
125
126		rcu_read_lock();
127		md5sig = rcu_dereference(tcp_sk(sk)->md5sig_info);
128		if (md5sig)
129			err = tcp_diag_put_md5sig(skb, md5sig);
130		rcu_read_unlock();
131		if (err < 0)
132			return err;
133	}
134#endif
135
136	ulp_ops = icsk->icsk_ulp_ops;
137	if (ulp_ops) {
138		err = tcp_diag_put_ulp(skb, sk, ulp_ops, net_admin);
139		if (err < 0)
140			return err;
141	}
142
143	return 0;
144}
145
146static size_t tcp_diag_get_aux_size(struct sock *sk, bool net_admin)
147{
148	struct inet_connection_sock *icsk = inet_csk(sk);
149	size_t size = 0;
150
151#ifdef CONFIG_TCP_MD5SIG
152	if (net_admin && sk_fullsock(sk)) {
153		const struct tcp_md5sig_info *md5sig;
154		const struct tcp_md5sig_key *key;
155		size_t md5sig_count = 0;
156
157		rcu_read_lock();
158		md5sig = rcu_dereference(tcp_sk(sk)->md5sig_info);
159		if (md5sig) {
160			hlist_for_each_entry_rcu(key, &md5sig->head, node)
161				md5sig_count++;
162		}
163		rcu_read_unlock();
164		size += nla_total_size(md5sig_count *
165				       sizeof(struct tcp_diag_md5sig));
166	}
167#endif
168
169	if (sk_fullsock(sk)) {
170		const struct tcp_ulp_ops *ulp_ops;
171
172		ulp_ops = icsk->icsk_ulp_ops;
173		if (ulp_ops) {
174			size += nla_total_size(0) +
175				nla_total_size(TCP_ULP_NAME_MAX);
176			if (ulp_ops->get_info_size)
177				size += ulp_ops->get_info_size(sk, net_admin);
178		}
179	}
180
181	return size
182		+ nla_total_size(sizeof(struct tcp_info))
183		+ nla_total_size(sizeof(struct inet_diag_msg))
184		+ inet_diag_msg_attrs_size()
185		+ nla_total_size(sizeof(struct inet_diag_meminfo))
186		+ nla_total_size(SK_MEMINFO_VARS * sizeof(u32))
187		+ nla_total_size(TCP_CA_NAME_MAX)
188		+ nla_total_size(sizeof(struct tcpvegas_info))
189		+ 64;
190}
191
192static int tcp_twsk_diag_fill(struct sock *sk,
193			      struct sk_buff *skb,
194			      struct netlink_callback *cb,
195			      u16 nlmsg_flags, bool net_admin)
196{
197	struct inet_timewait_sock *tw = inet_twsk(sk);
198	struct inet_diag_msg *r;
199	struct nlmsghdr *nlh;
200	long tmo;
201
202	nlh = nlmsg_put(skb, NETLINK_CB(cb->skb).portid,
203			cb->nlh->nlmsg_seq, cb->nlh->nlmsg_type,
204			sizeof(*r), nlmsg_flags);
205	if (!nlh)
206		return -EMSGSIZE;
207
208	r = nlmsg_data(nlh);
209	DEBUG_NET_WARN_ON_ONCE(tw->tw_state != TCP_TIME_WAIT);
210
211	inet_diag_msg_common_fill(r, sk);
212	r->idiag_retrans      = 0;
213
214	r->idiag_state	      = READ_ONCE(tw->tw_substate);
215	r->idiag_timer	      = 3;
216	tmo = tw->tw_timer.expires - jiffies;
217	r->idiag_expires      = jiffies_delta_to_msecs(tmo);
218	r->idiag_rqueue	      = 0;
219	r->idiag_wqueue	      = 0;
220	r->idiag_uid	      = 0;
221	r->idiag_inode	      = 0;
222
223	if (net_admin && nla_put_u32(skb, INET_DIAG_MARK,
224				     tw->tw_mark)) {
225		nlmsg_cancel(skb, nlh);
226		return -EMSGSIZE;
227	}
228
229	nlmsg_end(skb, nlh);
230	return 0;
231}
232
233static int tcp_req_diag_fill(struct sock *sk, struct sk_buff *skb,
234			     struct netlink_callback *cb,
235			     u16 nlmsg_flags, bool net_admin)
236{
237	struct request_sock *reqsk = inet_reqsk(sk);
238	struct inet_diag_msg *r;
239	struct nlmsghdr *nlh;
240	long tmo;
241
242	nlh = nlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
243			cb->nlh->nlmsg_type, sizeof(*r), nlmsg_flags);
244	if (!nlh)
245		return -EMSGSIZE;
246
247	r = nlmsg_data(nlh);
248	inet_diag_msg_common_fill(r, sk);
249	r->idiag_state = TCP_SYN_RECV;
250	r->idiag_timer = 1;
251	r->idiag_retrans = READ_ONCE(reqsk->num_retrans);
252
253	BUILD_BUG_ON(offsetof(struct inet_request_sock, ir_cookie) !=
254		     offsetof(struct sock, sk_cookie));
255
256	tmo = READ_ONCE(inet_reqsk(sk)->rsk_timer.expires) - jiffies;
257	r->idiag_expires = jiffies_delta_to_msecs(tmo);
258	r->idiag_rqueue	= 0;
259	r->idiag_wqueue	= 0;
260	r->idiag_uid	= 0;
261	r->idiag_inode	= 0;
262
263	if (net_admin && nla_put_u32(skb, INET_DIAG_MARK,
264				     inet_rsk(reqsk)->ir_mark)) {
265		nlmsg_cancel(skb, nlh);
266		return -EMSGSIZE;
267	}
268
269	nlmsg_end(skb, nlh);
270	return 0;
271}
272
273static int sk_diag_fill(struct sock *sk, struct sk_buff *skb,
274			struct netlink_callback *cb,
275			const struct inet_diag_req_v2 *r,
276			u16 nlmsg_flags, bool net_admin)
277{
278	if (sk->sk_state == TCP_TIME_WAIT)
279		return tcp_twsk_diag_fill(sk, skb, cb, nlmsg_flags, net_admin);
280
281	if (sk->sk_state == TCP_NEW_SYN_RECV)
282		return tcp_req_diag_fill(sk, skb, cb, nlmsg_flags, net_admin);
283
284	return inet_sk_diag_fill(sk, inet_csk(sk), skb, cb, r, nlmsg_flags,
285				 net_admin);
286}
287
288static void twsk_build_assert(void)
289{
290	BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_family) !=
291		     offsetof(struct sock, sk_family));
292
293	BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_num) !=
294		     offsetof(struct inet_sock, inet_num));
295
296	BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_dport) !=
297		     offsetof(struct inet_sock, inet_dport));
298
299	BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_rcv_saddr) !=
300		     offsetof(struct inet_sock, inet_rcv_saddr));
301
302	BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_daddr) !=
303		     offsetof(struct inet_sock, inet_daddr));
304
305#if IS_ENABLED(CONFIG_IPV6)
306	BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_v6_rcv_saddr) !=
307		     offsetof(struct sock, sk_v6_rcv_saddr));
308
309	BUILD_BUG_ON(offsetof(struct inet_timewait_sock, tw_v6_daddr) !=
310		     offsetof(struct sock, sk_v6_daddr));
311#endif
312}
313
314static void tcp_diag_dump(struct sk_buff *skb, struct netlink_callback *cb,
315			  const struct inet_diag_req_v2 *r)
316{
317	bool net_admin = netlink_net_capable(cb->skb, CAP_NET_ADMIN);
318	struct inet_diag_dump_data *cb_data = cb->data;
319	struct net *net = sock_net(skb->sk);
320	u32 idiag_states = r->idiag_states;
321	struct inet_hashinfo *hashinfo;
322	int i, num, s_i, s_num;
323	struct sock *sk;
324
325	hashinfo = net->ipv4.tcp_death_row.hashinfo;
326	if (idiag_states & TCPF_SYN_RECV)
327		idiag_states |= TCPF_NEW_SYN_RECV;
328	s_i = cb->args[1];
329	s_num = num = cb->args[2];
330
331	if (cb->args[0] == 0) {
332		if (!(idiag_states & TCPF_LISTEN) || r->id.idiag_dport)
333			goto skip_listen_ht;
334
335		for (i = s_i; i <= hashinfo->lhash2_mask; i++) {
336			struct inet_listen_hashbucket *ilb;
337			struct hlist_nulls_node *node;
338
339			num = 0;
340			ilb = &hashinfo->lhash2[i];
341
342			if (hlist_nulls_empty(&ilb->nulls_head)) {
343				s_num = 0;
344				continue;
345			}
346			spin_lock(&ilb->lock);
347			sk_nulls_for_each(sk, node, &ilb->nulls_head) {
348				struct inet_sock *inet = inet_sk(sk);
349
350				if (!net_eq(sock_net(sk), net))
351					continue;
352
353				if (num < s_num) {
354					num++;
355					continue;
356				}
357
358				if (r->sdiag_family != AF_UNSPEC &&
359				    sk->sk_family != r->sdiag_family)
360					goto next_listen;
361
362				if (r->id.idiag_sport != inet->inet_sport &&
363				    r->id.idiag_sport)
364					goto next_listen;
365
366				if (!inet_diag_bc_sk(cb_data, sk))
367					goto next_listen;
368
369				if (inet_sk_diag_fill(sk, inet_csk(sk), skb,
370						      cb, r, NLM_F_MULTI,
371						      net_admin) < 0) {
372					spin_unlock(&ilb->lock);
373					goto done;
374				}
375
376next_listen:
377				++num;
378			}
379			spin_unlock(&ilb->lock);
380
381			s_num = 0;
382		}
383skip_listen_ht:
384		cb->args[0] = 1;
385		s_i = num = s_num = 0;
386	}
387
388/* Process a maximum of SKARR_SZ sockets at a time when walking hash buckets
389 * with bh disabled.
390 */
391#define SKARR_SZ 16
392
393	/* Dump bound but inactive (not listening, connecting, etc.) sockets */
394	if (cb->args[0] == 1) {
395		if (!(idiag_states & TCPF_BOUND_INACTIVE))
396			goto skip_bind_ht;
397
398		for (i = s_i; i < hashinfo->bhash_size; i++) {
399			struct inet_bind_hashbucket *ibb;
400			struct inet_bind2_bucket *tb2;
401			struct sock *sk_arr[SKARR_SZ];
402			int num_arr[SKARR_SZ];
403			int idx, accum, res;
404
405resume_bind_walk:
406			num = 0;
407			accum = 0;
408			ibb = &hashinfo->bhash2[i];
409
410			if (hlist_empty(&ibb->chain)) {
411				s_num = 0;
412				continue;
413			}
414			spin_lock_bh(&ibb->lock);
415			inet_bind_bucket_for_each(tb2, &ibb->chain) {
416				if (!net_eq(ib2_net(tb2), net))
417					continue;
418
419				sk_for_each_bound(sk, &tb2->owners) {
420					struct inet_sock *inet = inet_sk(sk);
421
422					if (num < s_num)
423						goto next_bind;
424
425					if (sk->sk_state != TCP_CLOSE ||
426					    !inet->inet_num)
427						goto next_bind;
428
429					if (r->sdiag_family != AF_UNSPEC &&
430					    r->sdiag_family != sk->sk_family)
431						goto next_bind;
432
433					if (!inet_diag_bc_sk(cb_data, sk))
434						goto next_bind;
435
436					sock_hold(sk);
437					num_arr[accum] = num;
438					sk_arr[accum] = sk;
439					if (++accum == SKARR_SZ)
440						goto pause_bind_walk;
441next_bind:
442					num++;
443				}
444			}
445pause_bind_walk:
446			spin_unlock_bh(&ibb->lock);
447
448			res = 0;
449			for (idx = 0; idx < accum; idx++) {
450				if (res >= 0) {
451					res = inet_sk_diag_fill(sk_arr[idx],
452								NULL, skb, cb,
453								r, NLM_F_MULTI,
454								net_admin);
455					if (res < 0)
456						num = num_arr[idx];
457				}
458				sock_put(sk_arr[idx]);
459			}
460			if (res < 0)
461				goto done;
462
463			cond_resched();
464
465			if (accum == SKARR_SZ) {
466				s_num = num + 1;
467				goto resume_bind_walk;
468			}
469
470			s_num = 0;
471		}
472skip_bind_ht:
473		cb->args[0] = 2;
474		s_i = num = s_num = 0;
475	}
476
477	if (!(idiag_states & ~TCPF_LISTEN))
478		goto out;
479
480	for (i = s_i; i <= hashinfo->ehash_mask; i++) {
481		struct inet_ehash_bucket *head = &hashinfo->ehash[i];
482		spinlock_t *lock = inet_ehash_lockp(hashinfo, i);
483		struct hlist_nulls_node *node;
484		struct sock *sk_arr[SKARR_SZ];
485		int num_arr[SKARR_SZ];
486		int idx, accum, res;
487
488		if (hlist_nulls_empty(&head->chain))
489			continue;
490
491		if (i > s_i)
492			s_num = 0;
493
494next_chunk:
495		num = 0;
496		accum = 0;
497		spin_lock_bh(lock);
498		sk_nulls_for_each(sk, node, &head->chain) {
499			int state;
500
501			if (!net_eq(sock_net(sk), net))
502				continue;
503			if (num < s_num)
504				goto next_normal;
505			state = (sk->sk_state == TCP_TIME_WAIT) ?
506				READ_ONCE(inet_twsk(sk)->tw_substate) : sk->sk_state;
507			if (!(idiag_states & (1 << state)))
508				goto next_normal;
509			if (r->sdiag_family != AF_UNSPEC &&
510			    sk->sk_family != r->sdiag_family)
511				goto next_normal;
512			if (r->id.idiag_sport != htons(READ_ONCE(sk->sk_num)) &&
513			    r->id.idiag_sport)
514				goto next_normal;
515			if (r->id.idiag_dport != sk->sk_dport &&
516			    r->id.idiag_dport)
517				goto next_normal;
518			twsk_build_assert();
519
520			if (!inet_diag_bc_sk(cb_data, sk))
521				goto next_normal;
522
523			if (!refcount_inc_not_zero(&sk->sk_refcnt))
524				goto next_normal;
525
526			num_arr[accum] = num;
527			sk_arr[accum] = sk;
528			if (++accum == SKARR_SZ)
529				break;
530next_normal:
531			++num;
532		}
533		spin_unlock_bh(lock);
534
535		res = 0;
536		for (idx = 0; idx < accum; idx++) {
537			if (res >= 0) {
538				res = sk_diag_fill(sk_arr[idx], skb, cb, r,
539						   NLM_F_MULTI, net_admin);
540				if (res < 0)
541					num = num_arr[idx];
542			}
543			sock_gen_put(sk_arr[idx]);
544		}
545		if (res < 0)
546			break;
547
548		cond_resched();
549
550		if (accum == SKARR_SZ) {
551			s_num = num + 1;
552			goto next_chunk;
553		}
554	}
555
556done:
557	cb->args[1] = i;
558	cb->args[2] = num;
559out:
560	;
561}
562
563static struct sock *tcp_diag_find_one_icsk(struct net *net,
564					   const struct inet_diag_req_v2 *req)
565{
566	struct sock *sk;
567
568	rcu_read_lock();
569	if (req->sdiag_family == AF_INET) {
570		sk = inet_lookup(net, NULL, 0, req->id.idiag_dst[0],
571				 req->id.idiag_dport, req->id.idiag_src[0],
572				 req->id.idiag_sport, req->id.idiag_if);
573#if IS_ENABLED(CONFIG_IPV6)
574	} else if (req->sdiag_family == AF_INET6) {
575		if (ipv6_addr_v4mapped((struct in6_addr *)req->id.idiag_dst) &&
576		    ipv6_addr_v4mapped((struct in6_addr *)req->id.idiag_src))
577			sk = inet_lookup(net, NULL, 0, req->id.idiag_dst[3],
578					 req->id.idiag_dport, req->id.idiag_src[3],
579					 req->id.idiag_sport, req->id.idiag_if);
580		else
581			sk = inet6_lookup(net, NULL, 0,
582					  (struct in6_addr *)req->id.idiag_dst,
583					  req->id.idiag_dport,
584					  (struct in6_addr *)req->id.idiag_src,
585					  req->id.idiag_sport,
586					  req->id.idiag_if);
587#endif
588	} else {
589		rcu_read_unlock();
590		return ERR_PTR(-EINVAL);
591	}
592	rcu_read_unlock();
593	if (!sk)
594		return ERR_PTR(-ENOENT);
595
596	if (sock_diag_check_cookie(sk, req->id.idiag_cookie)) {
597		sock_gen_put(sk);
598		return ERR_PTR(-ENOENT);
599	}
600
601	return sk;
602}
603
604static int tcp_diag_dump_one(struct netlink_callback *cb,
605			     const struct inet_diag_req_v2 *req)
606{
607	struct sk_buff *in_skb = cb->skb;
608	struct sk_buff *rep;
609	struct sock *sk;
610	struct net *net;
611	bool net_admin;
612	int err;
613
614	net = sock_net(in_skb->sk);
615	sk = tcp_diag_find_one_icsk(net, req);
616	if (IS_ERR(sk))
617		return PTR_ERR(sk);
618
619	net_admin = netlink_net_capable(in_skb, CAP_NET_ADMIN);
620	rep = nlmsg_new(tcp_diag_get_aux_size(sk, net_admin), GFP_KERNEL);
621	if (!rep) {
622		err = -ENOMEM;
623		goto out;
624	}
625
626	err = sk_diag_fill(sk, rep, cb, req, 0, net_admin);
627	if (err < 0) {
628		WARN_ON(err == -EMSGSIZE);
629		nlmsg_free(rep);
630		goto out;
631	}
632	err = nlmsg_unicast(net->diag_nlsk, rep, NETLINK_CB(in_skb).portid);
633
634out:
635	if (sk)
636		sock_gen_put(sk);
637
638	return err;
639}
640
641#ifdef CONFIG_INET_DIAG_DESTROY
642static int tcp_diag_destroy(struct sk_buff *in_skb,
643			    const struct inet_diag_req_v2 *req)
644{
645	struct net *net = sock_net(in_skb->sk);
646	struct sock *sk;
647	int err;
648
649	sk = tcp_diag_find_one_icsk(net, req);
650	if (IS_ERR(sk))
651		return PTR_ERR(sk);
652
653	err = sock_diag_destroy(sk, ECONNABORTED);
654
655	sock_gen_put(sk);
656
657	return err;
658}
659#endif
660
661static const struct inet_diag_handler tcp_diag_handler = {
662	.owner			= THIS_MODULE,
663	.dump			= tcp_diag_dump,
664	.dump_one		= tcp_diag_dump_one,
665	.idiag_get_info		= tcp_diag_get_info,
666	.idiag_get_aux		= tcp_diag_get_aux,
667	.idiag_type		= IPPROTO_TCP,
668	.idiag_info_size	= sizeof(struct tcp_info),
669#ifdef CONFIG_INET_DIAG_DESTROY
670	.destroy		= tcp_diag_destroy,
671#endif
672};
673
674static int __init tcp_diag_init(void)
675{
676	return inet_diag_register(&tcp_diag_handler);
677}
678
679static void __exit tcp_diag_exit(void)
680{
681	inet_diag_unregister(&tcp_diag_handler);
682}
683
684module_init(tcp_diag_init);
685module_exit(tcp_diag_exit);
686MODULE_LICENSE("GPL");
687MODULE_DESCRIPTION("TCP socket monitoring via SOCK_DIAG");
688MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_NETLINK, NETLINK_SOCK_DIAG, 2-6 /* AF_INET - IPPROTO_TCP */);