xref: /linux/net/ipv4/af_inet.c (revision 12871a0bd67dd4db4418e1daafcd46e9d329ef10)
1 /*
2  * INET		An implementation of the TCP/IP protocol suite for the LINUX
3  *		operating system.  INET is implemented using the  BSD Socket
4  *		interface as the means of communication with the user level.
5  *
6  *		PF_INET protocol family socket handler.
7  *
8  * Authors:	Ross Biro
9  *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10  *		Florian La Roche, <flla@stud.uni-sb.de>
11  *		Alan Cox, <A.Cox@swansea.ac.uk>
12  *
13  * Changes (see also sock.c)
14  *
15  *		piggy,
16  *		Karl Knutson	:	Socket protocol table
17  *		A.N.Kuznetsov	:	Socket death error in accept().
18  *		John Richardson :	Fix non blocking error in connect()
19  *					so sockets that fail to connect
20  *					don't return -EINPROGRESS.
21  *		Alan Cox	:	Asynchronous I/O support
22  *		Alan Cox	:	Keep correct socket pointer on sock
23  *					structures
24  *					when accept() ed
25  *		Alan Cox	:	Semantics of SO_LINGER aren't state
26  *					moved to close when you look carefully.
27  *					With this fixed and the accept bug fixed
28  *					some RPC stuff seems happier.
29  *		Niibe Yutaka	:	4.4BSD style write async I/O
30  *		Alan Cox,
31  *		Tony Gale 	:	Fixed reuse semantics.
32  *		Alan Cox	:	bind() shouldn't abort existing but dead
33  *					sockets. Stops FTP netin:.. I hope.
34  *		Alan Cox	:	bind() works correctly for RAW sockets.
35  *					Note that FreeBSD at least was broken
36  *					in this respect so be careful with
37  *					compatibility tests...
38  *		Alan Cox	:	routing cache support
39  *		Alan Cox	:	memzero the socket structure for
40  *					compactness.
41  *		Matt Day	:	nonblock connect error handler
42  *		Alan Cox	:	Allow large numbers of pending sockets
43  *					(eg for big web sites), but only if
44  *					specifically application requested.
45  *		Alan Cox	:	New buffering throughout IP. Used
46  *					dumbly.
47  *		Alan Cox	:	New buffering now used smartly.
48  *		Alan Cox	:	BSD rather than common sense
49  *					interpretation of listen.
50  *		Germano Caronni	:	Assorted small races.
51  *		Alan Cox	:	sendmsg/recvmsg basic support.
52  *		Alan Cox	:	Only sendmsg/recvmsg now supported.
53  *		Alan Cox	:	Locked down bind (see security list).
54  *		Alan Cox	:	Loosened bind a little.
55  *		Mike McLagan	:	ADD/DEL DLCI Ioctls
56  *	Willy Konynenberg	:	Transparent proxying support.
57  *		David S. Miller	:	New socket lookup architecture.
58  *					Some other random speedups.
59  *		Cyrus Durgin	:	Cleaned up file for kmod hacks.
60  *		Andi Kleen	:	Fix inet_stream_connect TCP race.
61  *
62  *		This program is free software; you can redistribute it and/or
63  *		modify it under the terms of the GNU General Public License
64  *		as published by the Free Software Foundation; either version
65  *		2 of the License, or (at your option) any later version.
66  */
67 
68 #include <linux/err.h>
69 #include <linux/errno.h>
70 #include <linux/types.h>
71 #include <linux/socket.h>
72 #include <linux/in.h>
73 #include <linux/kernel.h>
74 #include <linux/module.h>
75 #include <linux/sched.h>
76 #include <linux/timer.h>
77 #include <linux/string.h>
78 #include <linux/sockios.h>
79 #include <linux/net.h>
80 #include <linux/capability.h>
81 #include <linux/fcntl.h>
82 #include <linux/mm.h>
83 #include <linux/interrupt.h>
84 #include <linux/stat.h>
85 #include <linux/init.h>
86 #include <linux/poll.h>
87 #include <linux/netfilter_ipv4.h>
88 #include <linux/random.h>
89 #include <linux/slab.h>
90 
91 #include <asm/uaccess.h>
92 #include <asm/system.h>
93 
94 #include <linux/inet.h>
95 #include <linux/igmp.h>
96 #include <linux/inetdevice.h>
97 #include <linux/netdevice.h>
98 #include <net/checksum.h>
99 #include <net/ip.h>
100 #include <net/protocol.h>
101 #include <net/arp.h>
102 #include <net/route.h>
103 #include <net/ip_fib.h>
104 #include <net/inet_connection_sock.h>
105 #include <net/tcp.h>
106 #include <net/udp.h>
107 #include <net/udplite.h>
108 #include <net/ping.h>
109 #include <linux/skbuff.h>
110 #include <net/sock.h>
111 #include <net/raw.h>
112 #include <net/icmp.h>
113 #include <net/ipip.h>
114 #include <net/inet_common.h>
115 #include <net/xfrm.h>
116 #include <net/net_namespace.h>
117 #ifdef CONFIG_IP_MROUTE
118 #include <linux/mroute.h>
119 #endif
120 
121 
122 /* The inetsw table contains everything that inet_create needs to
123  * build a new socket.
124  */
125 static struct list_head inetsw[SOCK_MAX];
126 static DEFINE_SPINLOCK(inetsw_lock);
127 
128 struct ipv4_config ipv4_config;
129 EXPORT_SYMBOL(ipv4_config);
130 
131 /* New destruction routine */
132 
133 void inet_sock_destruct(struct sock *sk)
134 {
135 	struct inet_sock *inet = inet_sk(sk);
136 
137 	__skb_queue_purge(&sk->sk_receive_queue);
138 	__skb_queue_purge(&sk->sk_error_queue);
139 
140 	sk_mem_reclaim(sk);
141 
142 	if (sk->sk_type == SOCK_STREAM && sk->sk_state != TCP_CLOSE) {
143 		pr_err("Attempt to release TCP socket in state %d %p\n",
144 		       sk->sk_state, sk);
145 		return;
146 	}
147 	if (!sock_flag(sk, SOCK_DEAD)) {
148 		pr_err("Attempt to release alive inet socket %p\n", sk);
149 		return;
150 	}
151 
152 	WARN_ON(atomic_read(&sk->sk_rmem_alloc));
153 	WARN_ON(atomic_read(&sk->sk_wmem_alloc));
154 	WARN_ON(sk->sk_wmem_queued);
155 	WARN_ON(sk->sk_forward_alloc);
156 
157 	kfree(rcu_dereference_protected(inet->inet_opt, 1));
158 	dst_release(rcu_dereference_check(sk->sk_dst_cache, 1));
159 	sk_refcnt_debug_dec(sk);
160 }
161 EXPORT_SYMBOL(inet_sock_destruct);
162 
163 /*
164  *	The routines beyond this point handle the behaviour of an AF_INET
165  *	socket object. Mostly it punts to the subprotocols of IP to do
166  *	the work.
167  */
168 
169 /*
170  *	Automatically bind an unbound socket.
171  */
172 
173 static int inet_autobind(struct sock *sk)
174 {
175 	struct inet_sock *inet;
176 	/* We may need to bind the socket. */
177 	lock_sock(sk);
178 	inet = inet_sk(sk);
179 	if (!inet->inet_num) {
180 		if (sk->sk_prot->get_port(sk, 0)) {
181 			release_sock(sk);
182 			return -EAGAIN;
183 		}
184 		inet->inet_sport = htons(inet->inet_num);
185 	}
186 	release_sock(sk);
187 	return 0;
188 }
189 
190 /*
191  *	Move a socket into listening state.
192  */
193 int inet_listen(struct socket *sock, int backlog)
194 {
195 	struct sock *sk = sock->sk;
196 	unsigned char old_state;
197 	int err;
198 
199 	lock_sock(sk);
200 
201 	err = -EINVAL;
202 	if (sock->state != SS_UNCONNECTED || sock->type != SOCK_STREAM)
203 		goto out;
204 
205 	old_state = sk->sk_state;
206 	if (!((1 << old_state) & (TCPF_CLOSE | TCPF_LISTEN)))
207 		goto out;
208 
209 	/* Really, if the socket is already in listen state
210 	 * we can only allow the backlog to be adjusted.
211 	 */
212 	if (old_state != TCP_LISTEN) {
213 		err = inet_csk_listen_start(sk, backlog);
214 		if (err)
215 			goto out;
216 	}
217 	sk->sk_max_ack_backlog = backlog;
218 	err = 0;
219 
220 out:
221 	release_sock(sk);
222 	return err;
223 }
224 EXPORT_SYMBOL(inet_listen);
225 
226 u32 inet_ehash_secret __read_mostly;
227 EXPORT_SYMBOL(inet_ehash_secret);
228 
229 /*
230  * inet_ehash_secret must be set exactly once
231  */
232 void build_ehash_secret(void)
233 {
234 	u32 rnd;
235 
236 	do {
237 		get_random_bytes(&rnd, sizeof(rnd));
238 	} while (rnd == 0);
239 
240 	cmpxchg(&inet_ehash_secret, 0, rnd);
241 }
242 EXPORT_SYMBOL(build_ehash_secret);
243 
244 static inline int inet_netns_ok(struct net *net, int protocol)
245 {
246 	int hash;
247 	const struct net_protocol *ipprot;
248 
249 	if (net_eq(net, &init_net))
250 		return 1;
251 
252 	hash = protocol & (MAX_INET_PROTOS - 1);
253 	ipprot = rcu_dereference(inet_protos[hash]);
254 
255 	if (ipprot == NULL)
256 		/* raw IP is OK */
257 		return 1;
258 	return ipprot->netns_ok;
259 }
260 
261 /*
262  *	Create an inet socket.
263  */
264 
265 static int inet_create(struct net *net, struct socket *sock, int protocol,
266 		       int kern)
267 {
268 	struct sock *sk;
269 	struct inet_protosw *answer;
270 	struct inet_sock *inet;
271 	struct proto *answer_prot;
272 	unsigned char answer_flags;
273 	char answer_no_check;
274 	int try_loading_module = 0;
275 	int err;
276 
277 	if (unlikely(!inet_ehash_secret))
278 		if (sock->type != SOCK_RAW && sock->type != SOCK_DGRAM)
279 			build_ehash_secret();
280 
281 	sock->state = SS_UNCONNECTED;
282 
283 	/* Look for the requested type/protocol pair. */
284 lookup_protocol:
285 	err = -ESOCKTNOSUPPORT;
286 	rcu_read_lock();
287 	list_for_each_entry_rcu(answer, &inetsw[sock->type], list) {
288 
289 		err = 0;
290 		/* Check the non-wild match. */
291 		if (protocol == answer->protocol) {
292 			if (protocol != IPPROTO_IP)
293 				break;
294 		} else {
295 			/* Check for the two wild cases. */
296 			if (IPPROTO_IP == protocol) {
297 				protocol = answer->protocol;
298 				break;
299 			}
300 			if (IPPROTO_IP == answer->protocol)
301 				break;
302 		}
303 		err = -EPROTONOSUPPORT;
304 	}
305 
306 	if (unlikely(err)) {
307 		if (try_loading_module < 2) {
308 			rcu_read_unlock();
309 			/*
310 			 * Be more specific, e.g. net-pf-2-proto-132-type-1
311 			 * (net-pf-PF_INET-proto-IPPROTO_SCTP-type-SOCK_STREAM)
312 			 */
313 			if (++try_loading_module == 1)
314 				request_module("net-pf-%d-proto-%d-type-%d",
315 					       PF_INET, protocol, sock->type);
316 			/*
317 			 * Fall back to generic, e.g. net-pf-2-proto-132
318 			 * (net-pf-PF_INET-proto-IPPROTO_SCTP)
319 			 */
320 			else
321 				request_module("net-pf-%d-proto-%d",
322 					       PF_INET, protocol);
323 			goto lookup_protocol;
324 		} else
325 			goto out_rcu_unlock;
326 	}
327 
328 	err = -EPERM;
329 	if (sock->type == SOCK_RAW && !kern && !capable(CAP_NET_RAW))
330 		goto out_rcu_unlock;
331 
332 	err = -EAFNOSUPPORT;
333 	if (!inet_netns_ok(net, protocol))
334 		goto out_rcu_unlock;
335 
336 	sock->ops = answer->ops;
337 	answer_prot = answer->prot;
338 	answer_no_check = answer->no_check;
339 	answer_flags = answer->flags;
340 	rcu_read_unlock();
341 
342 	WARN_ON(answer_prot->slab == NULL);
343 
344 	err = -ENOBUFS;
345 	sk = sk_alloc(net, PF_INET, GFP_KERNEL, answer_prot);
346 	if (sk == NULL)
347 		goto out;
348 
349 	err = 0;
350 	sk->sk_no_check = answer_no_check;
351 	if (INET_PROTOSW_REUSE & answer_flags)
352 		sk->sk_reuse = 1;
353 
354 	inet = inet_sk(sk);
355 	inet->is_icsk = (INET_PROTOSW_ICSK & answer_flags) != 0;
356 
357 	inet->nodefrag = 0;
358 
359 	if (SOCK_RAW == sock->type) {
360 		inet->inet_num = protocol;
361 		if (IPPROTO_RAW == protocol)
362 			inet->hdrincl = 1;
363 	}
364 
365 	if (ipv4_config.no_pmtu_disc)
366 		inet->pmtudisc = IP_PMTUDISC_DONT;
367 	else
368 		inet->pmtudisc = IP_PMTUDISC_WANT;
369 
370 	inet->inet_id = 0;
371 
372 	sock_init_data(sock, sk);
373 
374 	sk->sk_destruct	   = inet_sock_destruct;
375 	sk->sk_protocol	   = protocol;
376 	sk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;
377 
378 	inet->uc_ttl	= -1;
379 	inet->mc_loop	= 1;
380 	inet->mc_ttl	= 1;
381 	inet->mc_all	= 1;
382 	inet->mc_index	= 0;
383 	inet->mc_list	= NULL;
384 
385 	sk_refcnt_debug_inc(sk);
386 
387 	if (inet->inet_num) {
388 		/* It assumes that any protocol which allows
389 		 * the user to assign a number at socket
390 		 * creation time automatically
391 		 * shares.
392 		 */
393 		inet->inet_sport = htons(inet->inet_num);
394 		/* Add to protocol hash chains. */
395 		sk->sk_prot->hash(sk);
396 	}
397 
398 	if (sk->sk_prot->init) {
399 		err = sk->sk_prot->init(sk);
400 		if (err)
401 			sk_common_release(sk);
402 	}
403 out:
404 	return err;
405 out_rcu_unlock:
406 	rcu_read_unlock();
407 	goto out;
408 }
409 
410 
411 /*
412  *	The peer socket should always be NULL (or else). When we call this
413  *	function we are destroying the object and from then on nobody
414  *	should refer to it.
415  */
416 int inet_release(struct socket *sock)
417 {
418 	struct sock *sk = sock->sk;
419 
420 	if (sk) {
421 		long timeout;
422 
423 		sock_rps_reset_flow(sk);
424 
425 		/* Applications forget to leave groups before exiting */
426 		ip_mc_drop_socket(sk);
427 
428 		/* If linger is set, we don't return until the close
429 		 * is complete.  Otherwise we return immediately. The
430 		 * actually closing is done the same either way.
431 		 *
432 		 * If the close is due to the process exiting, we never
433 		 * linger..
434 		 */
435 		timeout = 0;
436 		if (sock_flag(sk, SOCK_LINGER) &&
437 		    !(current->flags & PF_EXITING))
438 			timeout = sk->sk_lingertime;
439 		sock->sk = NULL;
440 		sk->sk_prot->close(sk, timeout);
441 	}
442 	return 0;
443 }
444 EXPORT_SYMBOL(inet_release);
445 
446 /* It is off by default, see below. */
447 int sysctl_ip_nonlocal_bind __read_mostly;
448 EXPORT_SYMBOL(sysctl_ip_nonlocal_bind);
449 
450 int inet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
451 {
452 	struct sockaddr_in *addr = (struct sockaddr_in *)uaddr;
453 	struct sock *sk = sock->sk;
454 	struct inet_sock *inet = inet_sk(sk);
455 	unsigned short snum;
456 	int chk_addr_ret;
457 	int err;
458 
459 	/* If the socket has its own bind function then use it. (RAW) */
460 	if (sk->sk_prot->bind) {
461 		err = sk->sk_prot->bind(sk, uaddr, addr_len);
462 		goto out;
463 	}
464 	err = -EINVAL;
465 	if (addr_len < sizeof(struct sockaddr_in))
466 		goto out;
467 
468 	if (addr->sin_family != AF_INET)
469 		goto out;
470 
471 	chk_addr_ret = inet_addr_type(sock_net(sk), addr->sin_addr.s_addr);
472 
473 	/* Not specified by any standard per-se, however it breaks too
474 	 * many applications when removed.  It is unfortunate since
475 	 * allowing applications to make a non-local bind solves
476 	 * several problems with systems using dynamic addressing.
477 	 * (ie. your servers still start up even if your ISDN link
478 	 *  is temporarily down)
479 	 */
480 	err = -EADDRNOTAVAIL;
481 	if (!sysctl_ip_nonlocal_bind &&
482 	    !(inet->freebind || inet->transparent) &&
483 	    addr->sin_addr.s_addr != htonl(INADDR_ANY) &&
484 	    chk_addr_ret != RTN_LOCAL &&
485 	    chk_addr_ret != RTN_MULTICAST &&
486 	    chk_addr_ret != RTN_BROADCAST)
487 		goto out;
488 
489 	snum = ntohs(addr->sin_port);
490 	err = -EACCES;
491 	if (snum && snum < PROT_SOCK && !capable(CAP_NET_BIND_SERVICE))
492 		goto out;
493 
494 	/*      We keep a pair of addresses. rcv_saddr is the one
495 	 *      used by hash lookups, and saddr is used for transmit.
496 	 *
497 	 *      In the BSD API these are the same except where it
498 	 *      would be illegal to use them (multicast/broadcast) in
499 	 *      which case the sending device address is used.
500 	 */
501 	lock_sock(sk);
502 
503 	/* Check these errors (active socket, double bind). */
504 	err = -EINVAL;
505 	if (sk->sk_state != TCP_CLOSE || inet->inet_num)
506 		goto out_release_sock;
507 
508 	inet->inet_rcv_saddr = inet->inet_saddr = addr->sin_addr.s_addr;
509 	if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
510 		inet->inet_saddr = 0;  /* Use device */
511 
512 	/* Make sure we are allowed to bind here. */
513 	if (sk->sk_prot->get_port(sk, snum)) {
514 		inet->inet_saddr = inet->inet_rcv_saddr = 0;
515 		err = -EADDRINUSE;
516 		goto out_release_sock;
517 	}
518 
519 	if (inet->inet_rcv_saddr)
520 		sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
521 	if (snum)
522 		sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
523 	inet->inet_sport = htons(inet->inet_num);
524 	inet->inet_daddr = 0;
525 	inet->inet_dport = 0;
526 	sk_dst_reset(sk);
527 	err = 0;
528 out_release_sock:
529 	release_sock(sk);
530 out:
531 	return err;
532 }
533 EXPORT_SYMBOL(inet_bind);
534 
535 int inet_dgram_connect(struct socket *sock, struct sockaddr * uaddr,
536 		       int addr_len, int flags)
537 {
538 	struct sock *sk = sock->sk;
539 
540 	if (addr_len < sizeof(uaddr->sa_family))
541 		return -EINVAL;
542 	if (uaddr->sa_family == AF_UNSPEC)
543 		return sk->sk_prot->disconnect(sk, flags);
544 
545 	if (!inet_sk(sk)->inet_num && inet_autobind(sk))
546 		return -EAGAIN;
547 	return sk->sk_prot->connect(sk, (struct sockaddr *)uaddr, addr_len);
548 }
549 EXPORT_SYMBOL(inet_dgram_connect);
550 
551 static long inet_wait_for_connect(struct sock *sk, long timeo)
552 {
553 	DEFINE_WAIT(wait);
554 
555 	prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
556 
557 	/* Basic assumption: if someone sets sk->sk_err, he _must_
558 	 * change state of the socket from TCP_SYN_*.
559 	 * Connect() does not allow to get error notifications
560 	 * without closing the socket.
561 	 */
562 	while ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
563 		release_sock(sk);
564 		timeo = schedule_timeout(timeo);
565 		lock_sock(sk);
566 		if (signal_pending(current) || !timeo)
567 			break;
568 		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
569 	}
570 	finish_wait(sk_sleep(sk), &wait);
571 	return timeo;
572 }
573 
574 /*
575  *	Connect to a remote host. There is regrettably still a little
576  *	TCP 'magic' in here.
577  */
578 int inet_stream_connect(struct socket *sock, struct sockaddr *uaddr,
579 			int addr_len, int flags)
580 {
581 	struct sock *sk = sock->sk;
582 	int err;
583 	long timeo;
584 
585 	if (addr_len < sizeof(uaddr->sa_family))
586 		return -EINVAL;
587 
588 	lock_sock(sk);
589 
590 	if (uaddr->sa_family == AF_UNSPEC) {
591 		err = sk->sk_prot->disconnect(sk, flags);
592 		sock->state = err ? SS_DISCONNECTING : SS_UNCONNECTED;
593 		goto out;
594 	}
595 
596 	switch (sock->state) {
597 	default:
598 		err = -EINVAL;
599 		goto out;
600 	case SS_CONNECTED:
601 		err = -EISCONN;
602 		goto out;
603 	case SS_CONNECTING:
604 		err = -EALREADY;
605 		/* Fall out of switch with err, set for this state */
606 		break;
607 	case SS_UNCONNECTED:
608 		err = -EISCONN;
609 		if (sk->sk_state != TCP_CLOSE)
610 			goto out;
611 
612 		err = sk->sk_prot->connect(sk, uaddr, addr_len);
613 		if (err < 0)
614 			goto out;
615 
616 		sock->state = SS_CONNECTING;
617 
618 		/* Just entered SS_CONNECTING state; the only
619 		 * difference is that return value in non-blocking
620 		 * case is EINPROGRESS, rather than EALREADY.
621 		 */
622 		err = -EINPROGRESS;
623 		break;
624 	}
625 
626 	timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
627 
628 	if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
629 		/* Error code is set above */
630 		if (!timeo || !inet_wait_for_connect(sk, timeo))
631 			goto out;
632 
633 		err = sock_intr_errno(timeo);
634 		if (signal_pending(current))
635 			goto out;
636 	}
637 
638 	/* Connection was closed by RST, timeout, ICMP error
639 	 * or another process disconnected us.
640 	 */
641 	if (sk->sk_state == TCP_CLOSE)
642 		goto sock_error;
643 
644 	/* sk->sk_err may be not zero now, if RECVERR was ordered by user
645 	 * and error was received after socket entered established state.
646 	 * Hence, it is handled normally after connect() return successfully.
647 	 */
648 
649 	sock->state = SS_CONNECTED;
650 	err = 0;
651 out:
652 	release_sock(sk);
653 	return err;
654 
655 sock_error:
656 	err = sock_error(sk) ? : -ECONNABORTED;
657 	sock->state = SS_UNCONNECTED;
658 	if (sk->sk_prot->disconnect(sk, flags))
659 		sock->state = SS_DISCONNECTING;
660 	goto out;
661 }
662 EXPORT_SYMBOL(inet_stream_connect);
663 
664 /*
665  *	Accept a pending connection. The TCP layer now gives BSD semantics.
666  */
667 
668 int inet_accept(struct socket *sock, struct socket *newsock, int flags)
669 {
670 	struct sock *sk1 = sock->sk;
671 	int err = -EINVAL;
672 	struct sock *sk2 = sk1->sk_prot->accept(sk1, flags, &err);
673 
674 	if (!sk2)
675 		goto do_err;
676 
677 	lock_sock(sk2);
678 
679 	WARN_ON(!((1 << sk2->sk_state) &
680 		  (TCPF_ESTABLISHED | TCPF_CLOSE_WAIT | TCPF_CLOSE)));
681 
682 	sock_graft(sk2, newsock);
683 
684 	newsock->state = SS_CONNECTED;
685 	err = 0;
686 	release_sock(sk2);
687 do_err:
688 	return err;
689 }
690 EXPORT_SYMBOL(inet_accept);
691 
692 
693 /*
694  *	This does both peername and sockname.
695  */
696 int inet_getname(struct socket *sock, struct sockaddr *uaddr,
697 			int *uaddr_len, int peer)
698 {
699 	struct sock *sk		= sock->sk;
700 	struct inet_sock *inet	= inet_sk(sk);
701 	DECLARE_SOCKADDR(struct sockaddr_in *, sin, uaddr);
702 
703 	sin->sin_family = AF_INET;
704 	if (peer) {
705 		if (!inet->inet_dport ||
706 		    (((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_SYN_SENT)) &&
707 		     peer == 1))
708 			return -ENOTCONN;
709 		sin->sin_port = inet->inet_dport;
710 		sin->sin_addr.s_addr = inet->inet_daddr;
711 	} else {
712 		__be32 addr = inet->inet_rcv_saddr;
713 		if (!addr)
714 			addr = inet->inet_saddr;
715 		sin->sin_port = inet->inet_sport;
716 		sin->sin_addr.s_addr = addr;
717 	}
718 	memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
719 	*uaddr_len = sizeof(*sin);
720 	return 0;
721 }
722 EXPORT_SYMBOL(inet_getname);
723 
724 int inet_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
725 		 size_t size)
726 {
727 	struct sock *sk = sock->sk;
728 
729 	sock_rps_record_flow(sk);
730 
731 	/* We may need to bind the socket. */
732 	if (!inet_sk(sk)->inet_num && !sk->sk_prot->no_autobind &&
733 	    inet_autobind(sk))
734 		return -EAGAIN;
735 
736 	return sk->sk_prot->sendmsg(iocb, sk, msg, size);
737 }
738 EXPORT_SYMBOL(inet_sendmsg);
739 
740 ssize_t inet_sendpage(struct socket *sock, struct page *page, int offset,
741 		      size_t size, int flags)
742 {
743 	struct sock *sk = sock->sk;
744 
745 	sock_rps_record_flow(sk);
746 
747 	/* We may need to bind the socket. */
748 	if (!inet_sk(sk)->inet_num && !sk->sk_prot->no_autobind &&
749 	    inet_autobind(sk))
750 		return -EAGAIN;
751 
752 	if (sk->sk_prot->sendpage)
753 		return sk->sk_prot->sendpage(sk, page, offset, size, flags);
754 	return sock_no_sendpage(sock, page, offset, size, flags);
755 }
756 EXPORT_SYMBOL(inet_sendpage);
757 
758 int inet_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
759 		 size_t size, int flags)
760 {
761 	struct sock *sk = sock->sk;
762 	int addr_len = 0;
763 	int err;
764 
765 	sock_rps_record_flow(sk);
766 
767 	err = sk->sk_prot->recvmsg(iocb, sk, msg, size, flags & MSG_DONTWAIT,
768 				   flags & ~MSG_DONTWAIT, &addr_len);
769 	if (err >= 0)
770 		msg->msg_namelen = addr_len;
771 	return err;
772 }
773 EXPORT_SYMBOL(inet_recvmsg);
774 
775 int inet_shutdown(struct socket *sock, int how)
776 {
777 	struct sock *sk = sock->sk;
778 	int err = 0;
779 
780 	/* This should really check to make sure
781 	 * the socket is a TCP socket. (WHY AC...)
782 	 */
783 	how++; /* maps 0->1 has the advantage of making bit 1 rcvs and
784 		       1->2 bit 2 snds.
785 		       2->3 */
786 	if ((how & ~SHUTDOWN_MASK) || !how)	/* MAXINT->0 */
787 		return -EINVAL;
788 
789 	lock_sock(sk);
790 	if (sock->state == SS_CONNECTING) {
791 		if ((1 << sk->sk_state) &
792 		    (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE))
793 			sock->state = SS_DISCONNECTING;
794 		else
795 			sock->state = SS_CONNECTED;
796 	}
797 
798 	switch (sk->sk_state) {
799 	case TCP_CLOSE:
800 		err = -ENOTCONN;
801 		/* Hack to wake up other listeners, who can poll for
802 		   POLLHUP, even on eg. unconnected UDP sockets -- RR */
803 	default:
804 		sk->sk_shutdown |= how;
805 		if (sk->sk_prot->shutdown)
806 			sk->sk_prot->shutdown(sk, how);
807 		break;
808 
809 	/* Remaining two branches are temporary solution for missing
810 	 * close() in multithreaded environment. It is _not_ a good idea,
811 	 * but we have no choice until close() is repaired at VFS level.
812 	 */
813 	case TCP_LISTEN:
814 		if (!(how & RCV_SHUTDOWN))
815 			break;
816 		/* Fall through */
817 	case TCP_SYN_SENT:
818 		err = sk->sk_prot->disconnect(sk, O_NONBLOCK);
819 		sock->state = err ? SS_DISCONNECTING : SS_UNCONNECTED;
820 		break;
821 	}
822 
823 	/* Wake up anyone sleeping in poll. */
824 	sk->sk_state_change(sk);
825 	release_sock(sk);
826 	return err;
827 }
828 EXPORT_SYMBOL(inet_shutdown);
829 
830 /*
831  *	ioctl() calls you can issue on an INET socket. Most of these are
832  *	device configuration and stuff and very rarely used. Some ioctls
833  *	pass on to the socket itself.
834  *
835  *	NOTE: I like the idea of a module for the config stuff. ie ifconfig
836  *	loads the devconfigure module does its configuring and unloads it.
837  *	There's a good 20K of config code hanging around the kernel.
838  */
839 
840 int inet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
841 {
842 	struct sock *sk = sock->sk;
843 	int err = 0;
844 	struct net *net = sock_net(sk);
845 
846 	switch (cmd) {
847 	case SIOCGSTAMP:
848 		err = sock_get_timestamp(sk, (struct timeval __user *)arg);
849 		break;
850 	case SIOCGSTAMPNS:
851 		err = sock_get_timestampns(sk, (struct timespec __user *)arg);
852 		break;
853 	case SIOCADDRT:
854 	case SIOCDELRT:
855 	case SIOCRTMSG:
856 		err = ip_rt_ioctl(net, cmd, (void __user *)arg);
857 		break;
858 	case SIOCDARP:
859 	case SIOCGARP:
860 	case SIOCSARP:
861 		err = arp_ioctl(net, cmd, (void __user *)arg);
862 		break;
863 	case SIOCGIFADDR:
864 	case SIOCSIFADDR:
865 	case SIOCGIFBRDADDR:
866 	case SIOCSIFBRDADDR:
867 	case SIOCGIFNETMASK:
868 	case SIOCSIFNETMASK:
869 	case SIOCGIFDSTADDR:
870 	case SIOCSIFDSTADDR:
871 	case SIOCSIFPFLAGS:
872 	case SIOCGIFPFLAGS:
873 	case SIOCSIFFLAGS:
874 		err = devinet_ioctl(net, cmd, (void __user *)arg);
875 		break;
876 	default:
877 		if (sk->sk_prot->ioctl)
878 			err = sk->sk_prot->ioctl(sk, cmd, arg);
879 		else
880 			err = -ENOIOCTLCMD;
881 		break;
882 	}
883 	return err;
884 }
885 EXPORT_SYMBOL(inet_ioctl);
886 
887 #ifdef CONFIG_COMPAT
888 int inet_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
889 {
890 	struct sock *sk = sock->sk;
891 	int err = -ENOIOCTLCMD;
892 
893 	if (sk->sk_prot->compat_ioctl)
894 		err = sk->sk_prot->compat_ioctl(sk, cmd, arg);
895 
896 	return err;
897 }
898 #endif
899 
900 const struct proto_ops inet_stream_ops = {
901 	.family		   = PF_INET,
902 	.owner		   = THIS_MODULE,
903 	.release	   = inet_release,
904 	.bind		   = inet_bind,
905 	.connect	   = inet_stream_connect,
906 	.socketpair	   = sock_no_socketpair,
907 	.accept		   = inet_accept,
908 	.getname	   = inet_getname,
909 	.poll		   = tcp_poll,
910 	.ioctl		   = inet_ioctl,
911 	.listen		   = inet_listen,
912 	.shutdown	   = inet_shutdown,
913 	.setsockopt	   = sock_common_setsockopt,
914 	.getsockopt	   = sock_common_getsockopt,
915 	.sendmsg	   = inet_sendmsg,
916 	.recvmsg	   = inet_recvmsg,
917 	.mmap		   = sock_no_mmap,
918 	.sendpage	   = inet_sendpage,
919 	.splice_read	   = tcp_splice_read,
920 #ifdef CONFIG_COMPAT
921 	.compat_setsockopt = compat_sock_common_setsockopt,
922 	.compat_getsockopt = compat_sock_common_getsockopt,
923 	.compat_ioctl	   = inet_compat_ioctl,
924 #endif
925 };
926 EXPORT_SYMBOL(inet_stream_ops);
927 
928 const struct proto_ops inet_dgram_ops = {
929 	.family		   = PF_INET,
930 	.owner		   = THIS_MODULE,
931 	.release	   = inet_release,
932 	.bind		   = inet_bind,
933 	.connect	   = inet_dgram_connect,
934 	.socketpair	   = sock_no_socketpair,
935 	.accept		   = sock_no_accept,
936 	.getname	   = inet_getname,
937 	.poll		   = udp_poll,
938 	.ioctl		   = inet_ioctl,
939 	.listen		   = sock_no_listen,
940 	.shutdown	   = inet_shutdown,
941 	.setsockopt	   = sock_common_setsockopt,
942 	.getsockopt	   = sock_common_getsockopt,
943 	.sendmsg	   = inet_sendmsg,
944 	.recvmsg	   = inet_recvmsg,
945 	.mmap		   = sock_no_mmap,
946 	.sendpage	   = inet_sendpage,
947 #ifdef CONFIG_COMPAT
948 	.compat_setsockopt = compat_sock_common_setsockopt,
949 	.compat_getsockopt = compat_sock_common_getsockopt,
950 	.compat_ioctl	   = inet_compat_ioctl,
951 #endif
952 };
953 EXPORT_SYMBOL(inet_dgram_ops);
954 
955 /*
956  * For SOCK_RAW sockets; should be the same as inet_dgram_ops but without
957  * udp_poll
958  */
959 static const struct proto_ops inet_sockraw_ops = {
960 	.family		   = PF_INET,
961 	.owner		   = THIS_MODULE,
962 	.release	   = inet_release,
963 	.bind		   = inet_bind,
964 	.connect	   = inet_dgram_connect,
965 	.socketpair	   = sock_no_socketpair,
966 	.accept		   = sock_no_accept,
967 	.getname	   = inet_getname,
968 	.poll		   = datagram_poll,
969 	.ioctl		   = inet_ioctl,
970 	.listen		   = sock_no_listen,
971 	.shutdown	   = inet_shutdown,
972 	.setsockopt	   = sock_common_setsockopt,
973 	.getsockopt	   = sock_common_getsockopt,
974 	.sendmsg	   = inet_sendmsg,
975 	.recvmsg	   = inet_recvmsg,
976 	.mmap		   = sock_no_mmap,
977 	.sendpage	   = inet_sendpage,
978 #ifdef CONFIG_COMPAT
979 	.compat_setsockopt = compat_sock_common_setsockopt,
980 	.compat_getsockopt = compat_sock_common_getsockopt,
981 	.compat_ioctl	   = inet_compat_ioctl,
982 #endif
983 };
984 
985 static const struct net_proto_family inet_family_ops = {
986 	.family = PF_INET,
987 	.create = inet_create,
988 	.owner	= THIS_MODULE,
989 };
990 
991 /* Upon startup we insert all the elements in inetsw_array[] into
992  * the linked list inetsw.
993  */
994 static struct inet_protosw inetsw_array[] =
995 {
996 	{
997 		.type =       SOCK_STREAM,
998 		.protocol =   IPPROTO_TCP,
999 		.prot =       &tcp_prot,
1000 		.ops =        &inet_stream_ops,
1001 		.no_check =   0,
1002 		.flags =      INET_PROTOSW_PERMANENT |
1003 			      INET_PROTOSW_ICSK,
1004 	},
1005 
1006 	{
1007 		.type =       SOCK_DGRAM,
1008 		.protocol =   IPPROTO_UDP,
1009 		.prot =       &udp_prot,
1010 		.ops =        &inet_dgram_ops,
1011 		.no_check =   UDP_CSUM_DEFAULT,
1012 		.flags =      INET_PROTOSW_PERMANENT,
1013        },
1014 
1015        {
1016 		.type =       SOCK_DGRAM,
1017 		.protocol =   IPPROTO_ICMP,
1018 		.prot =       &ping_prot,
1019 		.ops =        &inet_dgram_ops,
1020 		.no_check =   UDP_CSUM_DEFAULT,
1021 		.flags =      INET_PROTOSW_REUSE,
1022        },
1023 
1024        {
1025 	       .type =       SOCK_RAW,
1026 	       .protocol =   IPPROTO_IP,	/* wild card */
1027 	       .prot =       &raw_prot,
1028 	       .ops =        &inet_sockraw_ops,
1029 	       .no_check =   UDP_CSUM_DEFAULT,
1030 	       .flags =      INET_PROTOSW_REUSE,
1031        }
1032 };
1033 
1034 #define INETSW_ARRAY_LEN ARRAY_SIZE(inetsw_array)
1035 
1036 void inet_register_protosw(struct inet_protosw *p)
1037 {
1038 	struct list_head *lh;
1039 	struct inet_protosw *answer;
1040 	int protocol = p->protocol;
1041 	struct list_head *last_perm;
1042 
1043 	spin_lock_bh(&inetsw_lock);
1044 
1045 	if (p->type >= SOCK_MAX)
1046 		goto out_illegal;
1047 
1048 	/* If we are trying to override a permanent protocol, bail. */
1049 	answer = NULL;
1050 	last_perm = &inetsw[p->type];
1051 	list_for_each(lh, &inetsw[p->type]) {
1052 		answer = list_entry(lh, struct inet_protosw, list);
1053 
1054 		/* Check only the non-wild match. */
1055 		if (INET_PROTOSW_PERMANENT & answer->flags) {
1056 			if (protocol == answer->protocol)
1057 				break;
1058 			last_perm = lh;
1059 		}
1060 
1061 		answer = NULL;
1062 	}
1063 	if (answer)
1064 		goto out_permanent;
1065 
1066 	/* Add the new entry after the last permanent entry if any, so that
1067 	 * the new entry does not override a permanent entry when matched with
1068 	 * a wild-card protocol. But it is allowed to override any existing
1069 	 * non-permanent entry.  This means that when we remove this entry, the
1070 	 * system automatically returns to the old behavior.
1071 	 */
1072 	list_add_rcu(&p->list, last_perm);
1073 out:
1074 	spin_unlock_bh(&inetsw_lock);
1075 
1076 	return;
1077 
1078 out_permanent:
1079 	printk(KERN_ERR "Attempt to override permanent protocol %d.\n",
1080 	       protocol);
1081 	goto out;
1082 
1083 out_illegal:
1084 	printk(KERN_ERR
1085 	       "Ignoring attempt to register invalid socket type %d.\n",
1086 	       p->type);
1087 	goto out;
1088 }
1089 EXPORT_SYMBOL(inet_register_protosw);
1090 
1091 void inet_unregister_protosw(struct inet_protosw *p)
1092 {
1093 	if (INET_PROTOSW_PERMANENT & p->flags) {
1094 		printk(KERN_ERR
1095 		       "Attempt to unregister permanent protocol %d.\n",
1096 		       p->protocol);
1097 	} else {
1098 		spin_lock_bh(&inetsw_lock);
1099 		list_del_rcu(&p->list);
1100 		spin_unlock_bh(&inetsw_lock);
1101 
1102 		synchronize_net();
1103 	}
1104 }
1105 EXPORT_SYMBOL(inet_unregister_protosw);
1106 
1107 /*
1108  *      Shall we try to damage output packets if routing dev changes?
1109  */
1110 
1111 int sysctl_ip_dynaddr __read_mostly;
1112 
1113 static int inet_sk_reselect_saddr(struct sock *sk)
1114 {
1115 	struct inet_sock *inet = inet_sk(sk);
1116 	__be32 old_saddr = inet->inet_saddr;
1117 	__be32 daddr = inet->inet_daddr;
1118 	struct flowi4 *fl4;
1119 	struct rtable *rt;
1120 	__be32 new_saddr;
1121 	struct ip_options_rcu *inet_opt;
1122 
1123 	inet_opt = rcu_dereference_protected(inet->inet_opt,
1124 					     sock_owned_by_user(sk));
1125 	if (inet_opt && inet_opt->opt.srr)
1126 		daddr = inet_opt->opt.faddr;
1127 
1128 	/* Query new route. */
1129 	fl4 = &inet->cork.fl.u.ip4;
1130 	rt = ip_route_connect(fl4, daddr, 0, RT_CONN_FLAGS(sk),
1131 			      sk->sk_bound_dev_if, sk->sk_protocol,
1132 			      inet->inet_sport, inet->inet_dport, sk, false);
1133 	if (IS_ERR(rt))
1134 		return PTR_ERR(rt);
1135 
1136 	sk_setup_caps(sk, &rt->dst);
1137 
1138 	new_saddr = fl4->saddr;
1139 
1140 	if (new_saddr == old_saddr)
1141 		return 0;
1142 
1143 	if (sysctl_ip_dynaddr > 1) {
1144 		printk(KERN_INFO "%s(): shifting inet->saddr from %pI4 to %pI4\n",
1145 		       __func__, &old_saddr, &new_saddr);
1146 	}
1147 
1148 	inet->inet_saddr = inet->inet_rcv_saddr = new_saddr;
1149 
1150 	/*
1151 	 * XXX The only one ugly spot where we need to
1152 	 * XXX really change the sockets identity after
1153 	 * XXX it has entered the hashes. -DaveM
1154 	 *
1155 	 * Besides that, it does not check for connection
1156 	 * uniqueness. Wait for troubles.
1157 	 */
1158 	__sk_prot_rehash(sk);
1159 	return 0;
1160 }
1161 
1162 int inet_sk_rebuild_header(struct sock *sk)
1163 {
1164 	struct inet_sock *inet = inet_sk(sk);
1165 	struct rtable *rt = (struct rtable *)__sk_dst_check(sk, 0);
1166 	__be32 daddr;
1167 	struct ip_options_rcu *inet_opt;
1168 	struct flowi4 *fl4;
1169 	int err;
1170 
1171 	/* Route is OK, nothing to do. */
1172 	if (rt)
1173 		return 0;
1174 
1175 	/* Reroute. */
1176 	rcu_read_lock();
1177 	inet_opt = rcu_dereference(inet->inet_opt);
1178 	daddr = inet->inet_daddr;
1179 	if (inet_opt && inet_opt->opt.srr)
1180 		daddr = inet_opt->opt.faddr;
1181 	rcu_read_unlock();
1182 	fl4 = &inet->cork.fl.u.ip4;
1183 	rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr, inet->inet_saddr,
1184 				   inet->inet_dport, inet->inet_sport,
1185 				   sk->sk_protocol, RT_CONN_FLAGS(sk),
1186 				   sk->sk_bound_dev_if);
1187 	if (!IS_ERR(rt)) {
1188 		err = 0;
1189 		sk_setup_caps(sk, &rt->dst);
1190 	} else {
1191 		err = PTR_ERR(rt);
1192 
1193 		/* Routing failed... */
1194 		sk->sk_route_caps = 0;
1195 		/*
1196 		 * Other protocols have to map its equivalent state to TCP_SYN_SENT.
1197 		 * DCCP maps its DCCP_REQUESTING state to TCP_SYN_SENT. -acme
1198 		 */
1199 		if (!sysctl_ip_dynaddr ||
1200 		    sk->sk_state != TCP_SYN_SENT ||
1201 		    (sk->sk_userlocks & SOCK_BINDADDR_LOCK) ||
1202 		    (err = inet_sk_reselect_saddr(sk)) != 0)
1203 			sk->sk_err_soft = -err;
1204 	}
1205 
1206 	return err;
1207 }
1208 EXPORT_SYMBOL(inet_sk_rebuild_header);
1209 
1210 static int inet_gso_send_check(struct sk_buff *skb)
1211 {
1212 	const struct iphdr *iph;
1213 	const struct net_protocol *ops;
1214 	int proto;
1215 	int ihl;
1216 	int err = -EINVAL;
1217 
1218 	if (unlikely(!pskb_may_pull(skb, sizeof(*iph))))
1219 		goto out;
1220 
1221 	iph = ip_hdr(skb);
1222 	ihl = iph->ihl * 4;
1223 	if (ihl < sizeof(*iph))
1224 		goto out;
1225 
1226 	if (unlikely(!pskb_may_pull(skb, ihl)))
1227 		goto out;
1228 
1229 	__skb_pull(skb, ihl);
1230 	skb_reset_transport_header(skb);
1231 	iph = ip_hdr(skb);
1232 	proto = iph->protocol & (MAX_INET_PROTOS - 1);
1233 	err = -EPROTONOSUPPORT;
1234 
1235 	rcu_read_lock();
1236 	ops = rcu_dereference(inet_protos[proto]);
1237 	if (likely(ops && ops->gso_send_check))
1238 		err = ops->gso_send_check(skb);
1239 	rcu_read_unlock();
1240 
1241 out:
1242 	return err;
1243 }
1244 
1245 static struct sk_buff *inet_gso_segment(struct sk_buff *skb, u32 features)
1246 {
1247 	struct sk_buff *segs = ERR_PTR(-EINVAL);
1248 	struct iphdr *iph;
1249 	const struct net_protocol *ops;
1250 	int proto;
1251 	int ihl;
1252 	int id;
1253 	unsigned int offset = 0;
1254 
1255 	if (!(features & NETIF_F_V4_CSUM))
1256 		features &= ~NETIF_F_SG;
1257 
1258 	if (unlikely(skb_shinfo(skb)->gso_type &
1259 		     ~(SKB_GSO_TCPV4 |
1260 		       SKB_GSO_UDP |
1261 		       SKB_GSO_DODGY |
1262 		       SKB_GSO_TCP_ECN |
1263 		       0)))
1264 		goto out;
1265 
1266 	if (unlikely(!pskb_may_pull(skb, sizeof(*iph))))
1267 		goto out;
1268 
1269 	iph = ip_hdr(skb);
1270 	ihl = iph->ihl * 4;
1271 	if (ihl < sizeof(*iph))
1272 		goto out;
1273 
1274 	if (unlikely(!pskb_may_pull(skb, ihl)))
1275 		goto out;
1276 
1277 	__skb_pull(skb, ihl);
1278 	skb_reset_transport_header(skb);
1279 	iph = ip_hdr(skb);
1280 	id = ntohs(iph->id);
1281 	proto = iph->protocol & (MAX_INET_PROTOS - 1);
1282 	segs = ERR_PTR(-EPROTONOSUPPORT);
1283 
1284 	rcu_read_lock();
1285 	ops = rcu_dereference(inet_protos[proto]);
1286 	if (likely(ops && ops->gso_segment))
1287 		segs = ops->gso_segment(skb, features);
1288 	rcu_read_unlock();
1289 
1290 	if (!segs || IS_ERR(segs))
1291 		goto out;
1292 
1293 	skb = segs;
1294 	do {
1295 		iph = ip_hdr(skb);
1296 		if (proto == IPPROTO_UDP) {
1297 			iph->id = htons(id);
1298 			iph->frag_off = htons(offset >> 3);
1299 			if (skb->next != NULL)
1300 				iph->frag_off |= htons(IP_MF);
1301 			offset += (skb->len - skb->mac_len - iph->ihl * 4);
1302 		} else
1303 			iph->id = htons(id++);
1304 		iph->tot_len = htons(skb->len - skb->mac_len);
1305 		iph->check = 0;
1306 		iph->check = ip_fast_csum(skb_network_header(skb), iph->ihl);
1307 	} while ((skb = skb->next));
1308 
1309 out:
1310 	return segs;
1311 }
1312 
1313 static struct sk_buff **inet_gro_receive(struct sk_buff **head,
1314 					 struct sk_buff *skb)
1315 {
1316 	const struct net_protocol *ops;
1317 	struct sk_buff **pp = NULL;
1318 	struct sk_buff *p;
1319 	const struct iphdr *iph;
1320 	unsigned int hlen;
1321 	unsigned int off;
1322 	unsigned int id;
1323 	int flush = 1;
1324 	int proto;
1325 
1326 	off = skb_gro_offset(skb);
1327 	hlen = off + sizeof(*iph);
1328 	iph = skb_gro_header_fast(skb, off);
1329 	if (skb_gro_header_hard(skb, hlen)) {
1330 		iph = skb_gro_header_slow(skb, hlen, off);
1331 		if (unlikely(!iph))
1332 			goto out;
1333 	}
1334 
1335 	proto = iph->protocol & (MAX_INET_PROTOS - 1);
1336 
1337 	rcu_read_lock();
1338 	ops = rcu_dereference(inet_protos[proto]);
1339 	if (!ops || !ops->gro_receive)
1340 		goto out_unlock;
1341 
1342 	if (*(u8 *)iph != 0x45)
1343 		goto out_unlock;
1344 
1345 	if (unlikely(ip_fast_csum((u8 *)iph, iph->ihl)))
1346 		goto out_unlock;
1347 
1348 	id = ntohl(*(__be32 *)&iph->id);
1349 	flush = (u16)((ntohl(*(__be32 *)iph) ^ skb_gro_len(skb)) | (id ^ IP_DF));
1350 	id >>= 16;
1351 
1352 	for (p = *head; p; p = p->next) {
1353 		struct iphdr *iph2;
1354 
1355 		if (!NAPI_GRO_CB(p)->same_flow)
1356 			continue;
1357 
1358 		iph2 = ip_hdr(p);
1359 
1360 		if ((iph->protocol ^ iph2->protocol) |
1361 		    (iph->tos ^ iph2->tos) |
1362 		    ((__force u32)iph->saddr ^ (__force u32)iph2->saddr) |
1363 		    ((__force u32)iph->daddr ^ (__force u32)iph2->daddr)) {
1364 			NAPI_GRO_CB(p)->same_flow = 0;
1365 			continue;
1366 		}
1367 
1368 		/* All fields must match except length and checksum. */
1369 		NAPI_GRO_CB(p)->flush |=
1370 			(iph->ttl ^ iph2->ttl) |
1371 			((u16)(ntohs(iph2->id) + NAPI_GRO_CB(p)->count) ^ id);
1372 
1373 		NAPI_GRO_CB(p)->flush |= flush;
1374 	}
1375 
1376 	NAPI_GRO_CB(skb)->flush |= flush;
1377 	skb_gro_pull(skb, sizeof(*iph));
1378 	skb_set_transport_header(skb, skb_gro_offset(skb));
1379 
1380 	pp = ops->gro_receive(head, skb);
1381 
1382 out_unlock:
1383 	rcu_read_unlock();
1384 
1385 out:
1386 	NAPI_GRO_CB(skb)->flush |= flush;
1387 
1388 	return pp;
1389 }
1390 
1391 static int inet_gro_complete(struct sk_buff *skb)
1392 {
1393 	const struct net_protocol *ops;
1394 	struct iphdr *iph = ip_hdr(skb);
1395 	int proto = iph->protocol & (MAX_INET_PROTOS - 1);
1396 	int err = -ENOSYS;
1397 	__be16 newlen = htons(skb->len - skb_network_offset(skb));
1398 
1399 	csum_replace2(&iph->check, iph->tot_len, newlen);
1400 	iph->tot_len = newlen;
1401 
1402 	rcu_read_lock();
1403 	ops = rcu_dereference(inet_protos[proto]);
1404 	if (WARN_ON(!ops || !ops->gro_complete))
1405 		goto out_unlock;
1406 
1407 	err = ops->gro_complete(skb);
1408 
1409 out_unlock:
1410 	rcu_read_unlock();
1411 
1412 	return err;
1413 }
1414 
1415 int inet_ctl_sock_create(struct sock **sk, unsigned short family,
1416 			 unsigned short type, unsigned char protocol,
1417 			 struct net *net)
1418 {
1419 	struct socket *sock;
1420 	int rc = sock_create_kern(family, type, protocol, &sock);
1421 
1422 	if (rc == 0) {
1423 		*sk = sock->sk;
1424 		(*sk)->sk_allocation = GFP_ATOMIC;
1425 		/*
1426 		 * Unhash it so that IP input processing does not even see it,
1427 		 * we do not wish this socket to see incoming packets.
1428 		 */
1429 		(*sk)->sk_prot->unhash(*sk);
1430 
1431 		sk_change_net(*sk, net);
1432 	}
1433 	return rc;
1434 }
1435 EXPORT_SYMBOL_GPL(inet_ctl_sock_create);
1436 
1437 unsigned long snmp_fold_field(void __percpu *mib[], int offt)
1438 {
1439 	unsigned long res = 0;
1440 	int i;
1441 
1442 	for_each_possible_cpu(i) {
1443 		res += *(((unsigned long *) per_cpu_ptr(mib[0], i)) + offt);
1444 		res += *(((unsigned long *) per_cpu_ptr(mib[1], i)) + offt);
1445 	}
1446 	return res;
1447 }
1448 EXPORT_SYMBOL_GPL(snmp_fold_field);
1449 
1450 #if BITS_PER_LONG==32
1451 
1452 u64 snmp_fold_field64(void __percpu *mib[], int offt, size_t syncp_offset)
1453 {
1454 	u64 res = 0;
1455 	int cpu;
1456 
1457 	for_each_possible_cpu(cpu) {
1458 		void *bhptr, *userptr;
1459 		struct u64_stats_sync *syncp;
1460 		u64 v_bh, v_user;
1461 		unsigned int start;
1462 
1463 		/* first mib used by softirq context, we must use _bh() accessors */
1464 		bhptr = per_cpu_ptr(SNMP_STAT_BHPTR(mib), cpu);
1465 		syncp = (struct u64_stats_sync *)(bhptr + syncp_offset);
1466 		do {
1467 			start = u64_stats_fetch_begin_bh(syncp);
1468 			v_bh = *(((u64 *) bhptr) + offt);
1469 		} while (u64_stats_fetch_retry_bh(syncp, start));
1470 
1471 		/* second mib used in USER context */
1472 		userptr = per_cpu_ptr(SNMP_STAT_USRPTR(mib), cpu);
1473 		syncp = (struct u64_stats_sync *)(userptr + syncp_offset);
1474 		do {
1475 			start = u64_stats_fetch_begin(syncp);
1476 			v_user = *(((u64 *) userptr) + offt);
1477 		} while (u64_stats_fetch_retry(syncp, start));
1478 
1479 		res += v_bh + v_user;
1480 	}
1481 	return res;
1482 }
1483 EXPORT_SYMBOL_GPL(snmp_fold_field64);
1484 #endif
1485 
1486 int snmp_mib_init(void __percpu *ptr[2], size_t mibsize, size_t align)
1487 {
1488 	BUG_ON(ptr == NULL);
1489 	ptr[0] = __alloc_percpu(mibsize, align);
1490 	if (!ptr[0])
1491 		goto err0;
1492 	ptr[1] = __alloc_percpu(mibsize, align);
1493 	if (!ptr[1])
1494 		goto err1;
1495 	return 0;
1496 err1:
1497 	free_percpu(ptr[0]);
1498 	ptr[0] = NULL;
1499 err0:
1500 	return -ENOMEM;
1501 }
1502 EXPORT_SYMBOL_GPL(snmp_mib_init);
1503 
1504 void snmp_mib_free(void __percpu *ptr[2])
1505 {
1506 	BUG_ON(ptr == NULL);
1507 	free_percpu(ptr[0]);
1508 	free_percpu(ptr[1]);
1509 	ptr[0] = ptr[1] = NULL;
1510 }
1511 EXPORT_SYMBOL_GPL(snmp_mib_free);
1512 
1513 #ifdef CONFIG_IP_MULTICAST
1514 static const struct net_protocol igmp_protocol = {
1515 	.handler =	igmp_rcv,
1516 	.netns_ok =	1,
1517 };
1518 #endif
1519 
1520 static const struct net_protocol tcp_protocol = {
1521 	.handler =	tcp_v4_rcv,
1522 	.err_handler =	tcp_v4_err,
1523 	.gso_send_check = tcp_v4_gso_send_check,
1524 	.gso_segment =	tcp_tso_segment,
1525 	.gro_receive =	tcp4_gro_receive,
1526 	.gro_complete =	tcp4_gro_complete,
1527 	.no_policy =	1,
1528 	.netns_ok =	1,
1529 };
1530 
1531 static const struct net_protocol udp_protocol = {
1532 	.handler =	udp_rcv,
1533 	.err_handler =	udp_err,
1534 	.gso_send_check = udp4_ufo_send_check,
1535 	.gso_segment = udp4_ufo_fragment,
1536 	.no_policy =	1,
1537 	.netns_ok =	1,
1538 };
1539 
1540 static const struct net_protocol icmp_protocol = {
1541 	.handler =	icmp_rcv,
1542 	.err_handler =	ping_err,
1543 	.no_policy =	1,
1544 	.netns_ok =	1,
1545 };
1546 
1547 static __net_init int ipv4_mib_init_net(struct net *net)
1548 {
1549 	if (snmp_mib_init((void __percpu **)net->mib.tcp_statistics,
1550 			  sizeof(struct tcp_mib),
1551 			  __alignof__(struct tcp_mib)) < 0)
1552 		goto err_tcp_mib;
1553 	if (snmp_mib_init((void __percpu **)net->mib.ip_statistics,
1554 			  sizeof(struct ipstats_mib),
1555 			  __alignof__(struct ipstats_mib)) < 0)
1556 		goto err_ip_mib;
1557 	if (snmp_mib_init((void __percpu **)net->mib.net_statistics,
1558 			  sizeof(struct linux_mib),
1559 			  __alignof__(struct linux_mib)) < 0)
1560 		goto err_net_mib;
1561 	if (snmp_mib_init((void __percpu **)net->mib.udp_statistics,
1562 			  sizeof(struct udp_mib),
1563 			  __alignof__(struct udp_mib)) < 0)
1564 		goto err_udp_mib;
1565 	if (snmp_mib_init((void __percpu **)net->mib.udplite_statistics,
1566 			  sizeof(struct udp_mib),
1567 			  __alignof__(struct udp_mib)) < 0)
1568 		goto err_udplite_mib;
1569 	if (snmp_mib_init((void __percpu **)net->mib.icmp_statistics,
1570 			  sizeof(struct icmp_mib),
1571 			  __alignof__(struct icmp_mib)) < 0)
1572 		goto err_icmp_mib;
1573 	if (snmp_mib_init((void __percpu **)net->mib.icmpmsg_statistics,
1574 			  sizeof(struct icmpmsg_mib),
1575 			  __alignof__(struct icmpmsg_mib)) < 0)
1576 		goto err_icmpmsg_mib;
1577 
1578 	tcp_mib_init(net);
1579 	return 0;
1580 
1581 err_icmpmsg_mib:
1582 	snmp_mib_free((void __percpu **)net->mib.icmp_statistics);
1583 err_icmp_mib:
1584 	snmp_mib_free((void __percpu **)net->mib.udplite_statistics);
1585 err_udplite_mib:
1586 	snmp_mib_free((void __percpu **)net->mib.udp_statistics);
1587 err_udp_mib:
1588 	snmp_mib_free((void __percpu **)net->mib.net_statistics);
1589 err_net_mib:
1590 	snmp_mib_free((void __percpu **)net->mib.ip_statistics);
1591 err_ip_mib:
1592 	snmp_mib_free((void __percpu **)net->mib.tcp_statistics);
1593 err_tcp_mib:
1594 	return -ENOMEM;
1595 }
1596 
1597 static __net_exit void ipv4_mib_exit_net(struct net *net)
1598 {
1599 	snmp_mib_free((void __percpu **)net->mib.icmpmsg_statistics);
1600 	snmp_mib_free((void __percpu **)net->mib.icmp_statistics);
1601 	snmp_mib_free((void __percpu **)net->mib.udplite_statistics);
1602 	snmp_mib_free((void __percpu **)net->mib.udp_statistics);
1603 	snmp_mib_free((void __percpu **)net->mib.net_statistics);
1604 	snmp_mib_free((void __percpu **)net->mib.ip_statistics);
1605 	snmp_mib_free((void __percpu **)net->mib.tcp_statistics);
1606 }
1607 
1608 static __net_initdata struct pernet_operations ipv4_mib_ops = {
1609 	.init = ipv4_mib_init_net,
1610 	.exit = ipv4_mib_exit_net,
1611 };
1612 
1613 static int __init init_ipv4_mibs(void)
1614 {
1615 	return register_pernet_subsys(&ipv4_mib_ops);
1616 }
1617 
1618 static int ipv4_proc_init(void);
1619 
1620 /*
1621  *	IP protocol layer initialiser
1622  */
1623 
1624 static struct packet_type ip_packet_type __read_mostly = {
1625 	.type = cpu_to_be16(ETH_P_IP),
1626 	.func = ip_rcv,
1627 	.gso_send_check = inet_gso_send_check,
1628 	.gso_segment = inet_gso_segment,
1629 	.gro_receive = inet_gro_receive,
1630 	.gro_complete = inet_gro_complete,
1631 };
1632 
1633 static int __init inet_init(void)
1634 {
1635 	struct sk_buff *dummy_skb;
1636 	struct inet_protosw *q;
1637 	struct list_head *r;
1638 	int rc = -EINVAL;
1639 
1640 	BUILD_BUG_ON(sizeof(struct inet_skb_parm) > sizeof(dummy_skb->cb));
1641 
1642 	sysctl_local_reserved_ports = kzalloc(65536 / 8, GFP_KERNEL);
1643 	if (!sysctl_local_reserved_ports)
1644 		goto out;
1645 
1646 	rc = proto_register(&tcp_prot, 1);
1647 	if (rc)
1648 		goto out_free_reserved_ports;
1649 
1650 	rc = proto_register(&udp_prot, 1);
1651 	if (rc)
1652 		goto out_unregister_tcp_proto;
1653 
1654 	rc = proto_register(&raw_prot, 1);
1655 	if (rc)
1656 		goto out_unregister_udp_proto;
1657 
1658 	rc = proto_register(&ping_prot, 1);
1659 	if (rc)
1660 		goto out_unregister_raw_proto;
1661 
1662 	/*
1663 	 *	Tell SOCKET that we are alive...
1664 	 */
1665 
1666 	(void)sock_register(&inet_family_ops);
1667 
1668 #ifdef CONFIG_SYSCTL
1669 	ip_static_sysctl_init();
1670 #endif
1671 
1672 	/*
1673 	 *	Add all the base protocols.
1674 	 */
1675 
1676 	if (inet_add_protocol(&icmp_protocol, IPPROTO_ICMP) < 0)
1677 		printk(KERN_CRIT "inet_init: Cannot add ICMP protocol\n");
1678 	if (inet_add_protocol(&udp_protocol, IPPROTO_UDP) < 0)
1679 		printk(KERN_CRIT "inet_init: Cannot add UDP protocol\n");
1680 	if (inet_add_protocol(&tcp_protocol, IPPROTO_TCP) < 0)
1681 		printk(KERN_CRIT "inet_init: Cannot add TCP protocol\n");
1682 #ifdef CONFIG_IP_MULTICAST
1683 	if (inet_add_protocol(&igmp_protocol, IPPROTO_IGMP) < 0)
1684 		printk(KERN_CRIT "inet_init: Cannot add IGMP protocol\n");
1685 #endif
1686 
1687 	/* Register the socket-side information for inet_create. */
1688 	for (r = &inetsw[0]; r < &inetsw[SOCK_MAX]; ++r)
1689 		INIT_LIST_HEAD(r);
1690 
1691 	for (q = inetsw_array; q < &inetsw_array[INETSW_ARRAY_LEN]; ++q)
1692 		inet_register_protosw(q);
1693 
1694 	/*
1695 	 *	Set the ARP module up
1696 	 */
1697 
1698 	arp_init();
1699 
1700 	/*
1701 	 *	Set the IP module up
1702 	 */
1703 
1704 	ip_init();
1705 
1706 	tcp_v4_init();
1707 
1708 	/* Setup TCP slab cache for open requests. */
1709 	tcp_init();
1710 
1711 	/* Setup UDP memory threshold */
1712 	udp_init();
1713 
1714 	/* Add UDP-Lite (RFC 3828) */
1715 	udplite4_register();
1716 
1717 	ping_init();
1718 
1719 	/*
1720 	 *	Set the ICMP layer up
1721 	 */
1722 
1723 	if (icmp_init() < 0)
1724 		panic("Failed to create the ICMP control socket.\n");
1725 
1726 	/*
1727 	 *	Initialise the multicast router
1728 	 */
1729 #if defined(CONFIG_IP_MROUTE)
1730 	if (ip_mr_init())
1731 		printk(KERN_CRIT "inet_init: Cannot init ipv4 mroute\n");
1732 #endif
1733 	/*
1734 	 *	Initialise per-cpu ipv4 mibs
1735 	 */
1736 
1737 	if (init_ipv4_mibs())
1738 		printk(KERN_CRIT "inet_init: Cannot init ipv4 mibs\n");
1739 
1740 	ipv4_proc_init();
1741 
1742 	ipfrag_init();
1743 
1744 	dev_add_pack(&ip_packet_type);
1745 
1746 	rc = 0;
1747 out:
1748 	return rc;
1749 out_unregister_raw_proto:
1750 	proto_unregister(&raw_prot);
1751 out_unregister_udp_proto:
1752 	proto_unregister(&udp_prot);
1753 out_unregister_tcp_proto:
1754 	proto_unregister(&tcp_prot);
1755 out_free_reserved_ports:
1756 	kfree(sysctl_local_reserved_ports);
1757 	goto out;
1758 }
1759 
1760 fs_initcall(inet_init);
1761 
1762 /* ------------------------------------------------------------------------ */
1763 
1764 #ifdef CONFIG_PROC_FS
1765 static int __init ipv4_proc_init(void)
1766 {
1767 	int rc = 0;
1768 
1769 	if (raw_proc_init())
1770 		goto out_raw;
1771 	if (tcp4_proc_init())
1772 		goto out_tcp;
1773 	if (udp4_proc_init())
1774 		goto out_udp;
1775 	if (ping_proc_init())
1776 		goto out_ping;
1777 	if (ip_misc_proc_init())
1778 		goto out_misc;
1779 out:
1780 	return rc;
1781 out_misc:
1782 	ping_proc_exit();
1783 out_ping:
1784 	udp4_proc_exit();
1785 out_udp:
1786 	tcp4_proc_exit();
1787 out_tcp:
1788 	raw_proc_exit();
1789 out_raw:
1790 	rc = -ENOMEM;
1791 	goto out;
1792 }
1793 
1794 #else /* CONFIG_PROC_FS */
1795 static int __init ipv4_proc_init(void)
1796 {
1797 	return 0;
1798 }
1799 #endif /* CONFIG_PROC_FS */
1800 
1801 MODULE_ALIAS_NETPROTO(PF_INET);
1802 
1803