xref: /linux/net/ipv4/af_inet.c (revision 3f0a50f345f78183f6e9b39c2f45ca5dcaa511ca)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * INET		An implementation of the TCP/IP protocol suite for the LINUX
4  *		operating system.  INET is implemented using the  BSD Socket
5  *		interface as the means of communication with the user level.
6  *
7  *		PF_INET protocol family socket handler.
8  *
9  * Authors:	Ross Biro
10  *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
11  *		Florian La Roche, <flla@stud.uni-sb.de>
12  *		Alan Cox, <A.Cox@swansea.ac.uk>
13  *
14  * Changes (see also sock.c)
15  *
16  *		piggy,
17  *		Karl Knutson	:	Socket protocol table
18  *		A.N.Kuznetsov	:	Socket death error in accept().
19  *		John Richardson :	Fix non blocking error in connect()
20  *					so sockets that fail to connect
21  *					don't return -EINPROGRESS.
22  *		Alan Cox	:	Asynchronous I/O support
23  *		Alan Cox	:	Keep correct socket pointer on sock
24  *					structures
25  *					when accept() ed
26  *		Alan Cox	:	Semantics of SO_LINGER aren't state
27  *					moved to close when you look carefully.
28  *					With this fixed and the accept bug fixed
29  *					some RPC stuff seems happier.
30  *		Niibe Yutaka	:	4.4BSD style write async I/O
31  *		Alan Cox,
32  *		Tony Gale 	:	Fixed reuse semantics.
33  *		Alan Cox	:	bind() shouldn't abort existing but dead
34  *					sockets. Stops FTP netin:.. I hope.
35  *		Alan Cox	:	bind() works correctly for RAW sockets.
36  *					Note that FreeBSD at least was broken
37  *					in this respect so be careful with
38  *					compatibility tests...
39  *		Alan Cox	:	routing cache support
40  *		Alan Cox	:	memzero the socket structure for
41  *					compactness.
42  *		Matt Day	:	nonblock connect error handler
43  *		Alan Cox	:	Allow large numbers of pending sockets
44  *					(eg for big web sites), but only if
45  *					specifically application requested.
46  *		Alan Cox	:	New buffering throughout IP. Used
47  *					dumbly.
48  *		Alan Cox	:	New buffering now used smartly.
49  *		Alan Cox	:	BSD rather than common sense
50  *					interpretation of listen.
51  *		Germano Caronni	:	Assorted small races.
52  *		Alan Cox	:	sendmsg/recvmsg basic support.
53  *		Alan Cox	:	Only sendmsg/recvmsg now supported.
54  *		Alan Cox	:	Locked down bind (see security list).
55  *		Alan Cox	:	Loosened bind a little.
56  *		Mike McLagan	:	ADD/DEL DLCI Ioctls
57  *	Willy Konynenberg	:	Transparent proxying support.
58  *		David S. Miller	:	New socket lookup architecture.
59  *					Some other random speedups.
60  *		Cyrus Durgin	:	Cleaned up file for kmod hacks.
61  *		Andi Kleen	:	Fix inet_stream_connect TCP race.
62  */
63 
64 #define pr_fmt(fmt) "IPv4: " fmt
65 
66 #include <linux/err.h>
67 #include <linux/errno.h>
68 #include <linux/types.h>
69 #include <linux/socket.h>
70 #include <linux/in.h>
71 #include <linux/kernel.h>
72 #include <linux/kmod.h>
73 #include <linux/sched.h>
74 #include <linux/timer.h>
75 #include <linux/string.h>
76 #include <linux/sockios.h>
77 #include <linux/net.h>
78 #include <linux/capability.h>
79 #include <linux/fcntl.h>
80 #include <linux/mm.h>
81 #include <linux/interrupt.h>
82 #include <linux/stat.h>
83 #include <linux/init.h>
84 #include <linux/poll.h>
85 #include <linux/netfilter_ipv4.h>
86 #include <linux/random.h>
87 #include <linux/slab.h>
88 
89 #include <linux/uaccess.h>
90 
91 #include <linux/inet.h>
92 #include <linux/igmp.h>
93 #include <linux/inetdevice.h>
94 #include <linux/netdevice.h>
95 #include <net/checksum.h>
96 #include <net/ip.h>
97 #include <net/protocol.h>
98 #include <net/arp.h>
99 #include <net/route.h>
100 #include <net/ip_fib.h>
101 #include <net/inet_connection_sock.h>
102 #include <net/gro.h>
103 #include <net/tcp.h>
104 #include <net/udp.h>
105 #include <net/udplite.h>
106 #include <net/ping.h>
107 #include <linux/skbuff.h>
108 #include <net/sock.h>
109 #include <net/raw.h>
110 #include <net/icmp.h>
111 #include <net/inet_common.h>
112 #include <net/ip_tunnels.h>
113 #include <net/xfrm.h>
114 #include <net/net_namespace.h>
115 #include <net/secure_seq.h>
116 #ifdef CONFIG_IP_MROUTE
117 #include <linux/mroute.h>
118 #endif
119 #include <net/l3mdev.h>
120 #include <net/compat.h>
121 
122 #include <trace/events/sock.h>
123 
124 /* The inetsw table contains everything that inet_create needs to
125  * build a new socket.
126  */
127 static struct list_head inetsw[SOCK_MAX];
128 static DEFINE_SPINLOCK(inetsw_lock);
129 
130 /* New destruction routine */
131 
132 void inet_sock_destruct(struct sock *sk)
133 {
134 	struct inet_sock *inet = inet_sk(sk);
135 
136 	__skb_queue_purge(&sk->sk_receive_queue);
137 	__skb_queue_purge(&sk->sk_error_queue);
138 
139 	sk_mem_reclaim_final(sk);
140 
141 	if (sk->sk_type == SOCK_STREAM && sk->sk_state != TCP_CLOSE) {
142 		pr_err("Attempt to release TCP socket in state %d %p\n",
143 		       sk->sk_state, sk);
144 		return;
145 	}
146 	if (!sock_flag(sk, SOCK_DEAD)) {
147 		pr_err("Attempt to release alive inet socket %p\n", sk);
148 		return;
149 	}
150 
151 	WARN_ON(atomic_read(&sk->sk_rmem_alloc));
152 	WARN_ON(refcount_read(&sk->sk_wmem_alloc));
153 	WARN_ON(sk->sk_wmem_queued);
154 	WARN_ON(sk_forward_alloc_get(sk));
155 
156 	kfree(rcu_dereference_protected(inet->inet_opt, 1));
157 	dst_release(rcu_dereference_protected(sk->sk_dst_cache, 1));
158 	dst_release(rcu_dereference_protected(sk->sk_rx_dst, 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, tcp_fastopen;
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 	WRITE_ONCE(sk->sk_max_ack_backlog, backlog);
210 	/* Really, if the socket is already in listen state
211 	 * we can only allow the backlog to be adjusted.
212 	 */
213 	if (old_state != TCP_LISTEN) {
214 		/* Enable TFO w/o requiring TCP_FASTOPEN socket option.
215 		 * Note that only TCP sockets (SOCK_STREAM) will reach here.
216 		 * Also fastopen backlog may already been set via the option
217 		 * because the socket was in TCP_LISTEN state previously but
218 		 * was shutdown() rather than close().
219 		 */
220 		tcp_fastopen = sock_net(sk)->ipv4.sysctl_tcp_fastopen;
221 		if ((tcp_fastopen & TFO_SERVER_WO_SOCKOPT1) &&
222 		    (tcp_fastopen & TFO_SERVER_ENABLE) &&
223 		    !inet_csk(sk)->icsk_accept_queue.fastopenq.max_qlen) {
224 			fastopen_queue_tune(sk, backlog);
225 			tcp_fastopen_init_key_once(sock_net(sk));
226 		}
227 
228 		err = inet_csk_listen_start(sk);
229 		if (err)
230 			goto out;
231 		tcp_call_bpf(sk, BPF_SOCK_OPS_TCP_LISTEN_CB, 0, NULL);
232 	}
233 	err = 0;
234 
235 out:
236 	release_sock(sk);
237 	return err;
238 }
239 EXPORT_SYMBOL(inet_listen);
240 
241 /*
242  *	Create an inet socket.
243  */
244 
245 static int inet_create(struct net *net, struct socket *sock, int protocol,
246 		       int kern)
247 {
248 	struct sock *sk;
249 	struct inet_protosw *answer;
250 	struct inet_sock *inet;
251 	struct proto *answer_prot;
252 	unsigned char answer_flags;
253 	int try_loading_module = 0;
254 	int err;
255 
256 	if (protocol < 0 || protocol >= IPPROTO_MAX)
257 		return -EINVAL;
258 
259 	sock->state = SS_UNCONNECTED;
260 
261 	/* Look for the requested type/protocol pair. */
262 lookup_protocol:
263 	err = -ESOCKTNOSUPPORT;
264 	rcu_read_lock();
265 	list_for_each_entry_rcu(answer, &inetsw[sock->type], list) {
266 
267 		err = 0;
268 		/* Check the non-wild match. */
269 		if (protocol == answer->protocol) {
270 			if (protocol != IPPROTO_IP)
271 				break;
272 		} else {
273 			/* Check for the two wild cases. */
274 			if (IPPROTO_IP == protocol) {
275 				protocol = answer->protocol;
276 				break;
277 			}
278 			if (IPPROTO_IP == answer->protocol)
279 				break;
280 		}
281 		err = -EPROTONOSUPPORT;
282 	}
283 
284 	if (unlikely(err)) {
285 		if (try_loading_module < 2) {
286 			rcu_read_unlock();
287 			/*
288 			 * Be more specific, e.g. net-pf-2-proto-132-type-1
289 			 * (net-pf-PF_INET-proto-IPPROTO_SCTP-type-SOCK_STREAM)
290 			 */
291 			if (++try_loading_module == 1)
292 				request_module("net-pf-%d-proto-%d-type-%d",
293 					       PF_INET, protocol, sock->type);
294 			/*
295 			 * Fall back to generic, e.g. net-pf-2-proto-132
296 			 * (net-pf-PF_INET-proto-IPPROTO_SCTP)
297 			 */
298 			else
299 				request_module("net-pf-%d-proto-%d",
300 					       PF_INET, protocol);
301 			goto lookup_protocol;
302 		} else
303 			goto out_rcu_unlock;
304 	}
305 
306 	err = -EPERM;
307 	if (sock->type == SOCK_RAW && !kern &&
308 	    !ns_capable(net->user_ns, CAP_NET_RAW))
309 		goto out_rcu_unlock;
310 
311 	sock->ops = answer->ops;
312 	answer_prot = answer->prot;
313 	answer_flags = answer->flags;
314 	rcu_read_unlock();
315 
316 	WARN_ON(!answer_prot->slab);
317 
318 	err = -ENOMEM;
319 	sk = sk_alloc(net, PF_INET, GFP_KERNEL, answer_prot, kern);
320 	if (!sk)
321 		goto out;
322 
323 	err = 0;
324 	if (INET_PROTOSW_REUSE & answer_flags)
325 		sk->sk_reuse = SK_CAN_REUSE;
326 
327 	inet = inet_sk(sk);
328 	inet->is_icsk = (INET_PROTOSW_ICSK & answer_flags) != 0;
329 
330 	inet->nodefrag = 0;
331 
332 	if (SOCK_RAW == sock->type) {
333 		inet->inet_num = protocol;
334 		if (IPPROTO_RAW == protocol)
335 			inet->hdrincl = 1;
336 	}
337 
338 	if (net->ipv4.sysctl_ip_no_pmtu_disc)
339 		inet->pmtudisc = IP_PMTUDISC_DONT;
340 	else
341 		inet->pmtudisc = IP_PMTUDISC_WANT;
342 
343 	inet->inet_id = 0;
344 
345 	sock_init_data(sock, sk);
346 
347 	sk->sk_destruct	   = inet_sock_destruct;
348 	sk->sk_protocol	   = protocol;
349 	sk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;
350 
351 	inet->uc_ttl	= -1;
352 	inet->mc_loop	= 1;
353 	inet->mc_ttl	= 1;
354 	inet->mc_all	= 1;
355 	inet->mc_index	= 0;
356 	inet->mc_list	= NULL;
357 	inet->rcv_tos	= 0;
358 
359 	sk_refcnt_debug_inc(sk);
360 
361 	if (inet->inet_num) {
362 		/* It assumes that any protocol which allows
363 		 * the user to assign a number at socket
364 		 * creation time automatically
365 		 * shares.
366 		 */
367 		inet->inet_sport = htons(inet->inet_num);
368 		/* Add to protocol hash chains. */
369 		err = sk->sk_prot->hash(sk);
370 		if (err) {
371 			sk_common_release(sk);
372 			goto out;
373 		}
374 	}
375 
376 	if (sk->sk_prot->init) {
377 		err = sk->sk_prot->init(sk);
378 		if (err) {
379 			sk_common_release(sk);
380 			goto out;
381 		}
382 	}
383 
384 	if (!kern) {
385 		err = BPF_CGROUP_RUN_PROG_INET_SOCK(sk);
386 		if (err) {
387 			sk_common_release(sk);
388 			goto out;
389 		}
390 	}
391 out:
392 	return err;
393 out_rcu_unlock:
394 	rcu_read_unlock();
395 	goto out;
396 }
397 
398 
399 /*
400  *	The peer socket should always be NULL (or else). When we call this
401  *	function we are destroying the object and from then on nobody
402  *	should refer to it.
403  */
404 int inet_release(struct socket *sock)
405 {
406 	struct sock *sk = sock->sk;
407 
408 	if (sk) {
409 		long timeout;
410 
411 		if (!sk->sk_kern_sock)
412 			BPF_CGROUP_RUN_PROG_INET_SOCK_RELEASE(sk);
413 
414 		/* Applications forget to leave groups before exiting */
415 		ip_mc_drop_socket(sk);
416 
417 		/* If linger is set, we don't return until the close
418 		 * is complete.  Otherwise we return immediately. The
419 		 * actually closing is done the same either way.
420 		 *
421 		 * If the close is due to the process exiting, we never
422 		 * linger..
423 		 */
424 		timeout = 0;
425 		if (sock_flag(sk, SOCK_LINGER) &&
426 		    !(current->flags & PF_EXITING))
427 			timeout = sk->sk_lingertime;
428 		sk->sk_prot->close(sk, timeout);
429 		sock->sk = NULL;
430 	}
431 	return 0;
432 }
433 EXPORT_SYMBOL(inet_release);
434 
435 int inet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
436 {
437 	struct sock *sk = sock->sk;
438 	u32 flags = BIND_WITH_LOCK;
439 	int err;
440 
441 	/* If the socket has its own bind function then use it. (RAW) */
442 	if (sk->sk_prot->bind) {
443 		return sk->sk_prot->bind(sk, uaddr, addr_len);
444 	}
445 	if (addr_len < sizeof(struct sockaddr_in))
446 		return -EINVAL;
447 
448 	/* BPF prog is run before any checks are done so that if the prog
449 	 * changes context in a wrong way it will be caught.
450 	 */
451 	err = BPF_CGROUP_RUN_PROG_INET_BIND_LOCK(sk, uaddr,
452 						 CGROUP_INET4_BIND, &flags);
453 	if (err)
454 		return err;
455 
456 	return __inet_bind(sk, uaddr, addr_len, flags);
457 }
458 EXPORT_SYMBOL(inet_bind);
459 
460 int __inet_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len,
461 		u32 flags)
462 {
463 	struct sockaddr_in *addr = (struct sockaddr_in *)uaddr;
464 	struct inet_sock *inet = inet_sk(sk);
465 	struct net *net = sock_net(sk);
466 	unsigned short snum;
467 	int chk_addr_ret;
468 	u32 tb_id = RT_TABLE_LOCAL;
469 	int err;
470 
471 	if (addr->sin_family != AF_INET) {
472 		/* Compatibility games : accept AF_UNSPEC (mapped to AF_INET)
473 		 * only if s_addr is INADDR_ANY.
474 		 */
475 		err = -EAFNOSUPPORT;
476 		if (addr->sin_family != AF_UNSPEC ||
477 		    addr->sin_addr.s_addr != htonl(INADDR_ANY))
478 			goto out;
479 	}
480 
481 	tb_id = l3mdev_fib_table_by_index(net, sk->sk_bound_dev_if) ? : tb_id;
482 	chk_addr_ret = inet_addr_type_table(net, addr->sin_addr.s_addr, tb_id);
483 
484 	/* Not specified by any standard per-se, however it breaks too
485 	 * many applications when removed.  It is unfortunate since
486 	 * allowing applications to make a non-local bind solves
487 	 * several problems with systems using dynamic addressing.
488 	 * (ie. your servers still start up even if your ISDN link
489 	 *  is temporarily down)
490 	 */
491 	err = -EADDRNOTAVAIL;
492 	if (!inet_addr_valid_or_nonlocal(net, inet, addr->sin_addr.s_addr,
493 	                                 chk_addr_ret))
494 		goto out;
495 
496 	snum = ntohs(addr->sin_port);
497 	err = -EACCES;
498 	if (!(flags & BIND_NO_CAP_NET_BIND_SERVICE) &&
499 	    snum && inet_port_requires_bind_service(net, snum) &&
500 	    !ns_capable(net->user_ns, CAP_NET_BIND_SERVICE))
501 		goto out;
502 
503 	/*      We keep a pair of addresses. rcv_saddr is the one
504 	 *      used by hash lookups, and saddr is used for transmit.
505 	 *
506 	 *      In the BSD API these are the same except where it
507 	 *      would be illegal to use them (multicast/broadcast) in
508 	 *      which case the sending device address is used.
509 	 */
510 	if (flags & BIND_WITH_LOCK)
511 		lock_sock(sk);
512 
513 	/* Check these errors (active socket, double bind). */
514 	err = -EINVAL;
515 	if (sk->sk_state != TCP_CLOSE || inet->inet_num)
516 		goto out_release_sock;
517 
518 	inet->inet_rcv_saddr = inet->inet_saddr = addr->sin_addr.s_addr;
519 	if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
520 		inet->inet_saddr = 0;  /* Use device */
521 
522 	/* Make sure we are allowed to bind here. */
523 	if (snum || !(inet->bind_address_no_port ||
524 		      (flags & BIND_FORCE_ADDRESS_NO_PORT))) {
525 		if (sk->sk_prot->get_port(sk, snum)) {
526 			inet->inet_saddr = inet->inet_rcv_saddr = 0;
527 			err = -EADDRINUSE;
528 			goto out_release_sock;
529 		}
530 		if (!(flags & BIND_FROM_BPF)) {
531 			err = BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk);
532 			if (err) {
533 				inet->inet_saddr = inet->inet_rcv_saddr = 0;
534 				if (sk->sk_prot->put_port)
535 					sk->sk_prot->put_port(sk);
536 				goto out_release_sock;
537 			}
538 		}
539 	}
540 
541 	if (inet->inet_rcv_saddr)
542 		sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
543 	if (snum)
544 		sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
545 	inet->inet_sport = htons(inet->inet_num);
546 	inet->inet_daddr = 0;
547 	inet->inet_dport = 0;
548 	sk_dst_reset(sk);
549 	err = 0;
550 out_release_sock:
551 	if (flags & BIND_WITH_LOCK)
552 		release_sock(sk);
553 out:
554 	return err;
555 }
556 
557 int inet_dgram_connect(struct socket *sock, struct sockaddr *uaddr,
558 		       int addr_len, int flags)
559 {
560 	struct sock *sk = sock->sk;
561 	int err;
562 
563 	if (addr_len < sizeof(uaddr->sa_family))
564 		return -EINVAL;
565 	if (uaddr->sa_family == AF_UNSPEC)
566 		return sk->sk_prot->disconnect(sk, flags);
567 
568 	if (BPF_CGROUP_PRE_CONNECT_ENABLED(sk)) {
569 		err = sk->sk_prot->pre_connect(sk, uaddr, addr_len);
570 		if (err)
571 			return err;
572 	}
573 
574 	if (data_race(!inet_sk(sk)->inet_num) && inet_autobind(sk))
575 		return -EAGAIN;
576 	return sk->sk_prot->connect(sk, uaddr, addr_len);
577 }
578 EXPORT_SYMBOL(inet_dgram_connect);
579 
580 static long inet_wait_for_connect(struct sock *sk, long timeo, int writebias)
581 {
582 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
583 
584 	add_wait_queue(sk_sleep(sk), &wait);
585 	sk->sk_write_pending += writebias;
586 
587 	/* Basic assumption: if someone sets sk->sk_err, he _must_
588 	 * change state of the socket from TCP_SYN_*.
589 	 * Connect() does not allow to get error notifications
590 	 * without closing the socket.
591 	 */
592 	while ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
593 		release_sock(sk);
594 		timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
595 		lock_sock(sk);
596 		if (signal_pending(current) || !timeo)
597 			break;
598 	}
599 	remove_wait_queue(sk_sleep(sk), &wait);
600 	sk->sk_write_pending -= writebias;
601 	return timeo;
602 }
603 
604 /*
605  *	Connect to a remote host. There is regrettably still a little
606  *	TCP 'magic' in here.
607  */
608 int __inet_stream_connect(struct socket *sock, struct sockaddr *uaddr,
609 			  int addr_len, int flags, int is_sendmsg)
610 {
611 	struct sock *sk = sock->sk;
612 	int err;
613 	long timeo;
614 
615 	/*
616 	 * uaddr can be NULL and addr_len can be 0 if:
617 	 * sk is a TCP fastopen active socket and
618 	 * TCP_FASTOPEN_CONNECT sockopt is set and
619 	 * we already have a valid cookie for this socket.
620 	 * In this case, user can call write() after connect().
621 	 * write() will invoke tcp_sendmsg_fastopen() which calls
622 	 * __inet_stream_connect().
623 	 */
624 	if (uaddr) {
625 		if (addr_len < sizeof(uaddr->sa_family))
626 			return -EINVAL;
627 
628 		if (uaddr->sa_family == AF_UNSPEC) {
629 			err = sk->sk_prot->disconnect(sk, flags);
630 			sock->state = err ? SS_DISCONNECTING : SS_UNCONNECTED;
631 			goto out;
632 		}
633 	}
634 
635 	switch (sock->state) {
636 	default:
637 		err = -EINVAL;
638 		goto out;
639 	case SS_CONNECTED:
640 		err = -EISCONN;
641 		goto out;
642 	case SS_CONNECTING:
643 		if (inet_sk(sk)->defer_connect)
644 			err = is_sendmsg ? -EINPROGRESS : -EISCONN;
645 		else
646 			err = -EALREADY;
647 		/* Fall out of switch with err, set for this state */
648 		break;
649 	case SS_UNCONNECTED:
650 		err = -EISCONN;
651 		if (sk->sk_state != TCP_CLOSE)
652 			goto out;
653 
654 		if (BPF_CGROUP_PRE_CONNECT_ENABLED(sk)) {
655 			err = sk->sk_prot->pre_connect(sk, uaddr, addr_len);
656 			if (err)
657 				goto out;
658 		}
659 
660 		err = sk->sk_prot->connect(sk, uaddr, addr_len);
661 		if (err < 0)
662 			goto out;
663 
664 		sock->state = SS_CONNECTING;
665 
666 		if (!err && inet_sk(sk)->defer_connect)
667 			goto out;
668 
669 		/* Just entered SS_CONNECTING state; the only
670 		 * difference is that return value in non-blocking
671 		 * case is EINPROGRESS, rather than EALREADY.
672 		 */
673 		err = -EINPROGRESS;
674 		break;
675 	}
676 
677 	timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
678 
679 	if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
680 		int writebias = (sk->sk_protocol == IPPROTO_TCP) &&
681 				tcp_sk(sk)->fastopen_req &&
682 				tcp_sk(sk)->fastopen_req->data ? 1 : 0;
683 
684 		/* Error code is set above */
685 		if (!timeo || !inet_wait_for_connect(sk, timeo, writebias))
686 			goto out;
687 
688 		err = sock_intr_errno(timeo);
689 		if (signal_pending(current))
690 			goto out;
691 	}
692 
693 	/* Connection was closed by RST, timeout, ICMP error
694 	 * or another process disconnected us.
695 	 */
696 	if (sk->sk_state == TCP_CLOSE)
697 		goto sock_error;
698 
699 	/* sk->sk_err may be not zero now, if RECVERR was ordered by user
700 	 * and error was received after socket entered established state.
701 	 * Hence, it is handled normally after connect() return successfully.
702 	 */
703 
704 	sock->state = SS_CONNECTED;
705 	err = 0;
706 out:
707 	return err;
708 
709 sock_error:
710 	err = sock_error(sk) ? : -ECONNABORTED;
711 	sock->state = SS_UNCONNECTED;
712 	if (sk->sk_prot->disconnect(sk, flags))
713 		sock->state = SS_DISCONNECTING;
714 	goto out;
715 }
716 EXPORT_SYMBOL(__inet_stream_connect);
717 
718 int inet_stream_connect(struct socket *sock, struct sockaddr *uaddr,
719 			int addr_len, int flags)
720 {
721 	int err;
722 
723 	lock_sock(sock->sk);
724 	err = __inet_stream_connect(sock, uaddr, addr_len, flags, 0);
725 	release_sock(sock->sk);
726 	return err;
727 }
728 EXPORT_SYMBOL(inet_stream_connect);
729 
730 /*
731  *	Accept a pending connection. The TCP layer now gives BSD semantics.
732  */
733 
734 int inet_accept(struct socket *sock, struct socket *newsock, int flags,
735 		bool kern)
736 {
737 	struct sock *sk1 = sock->sk;
738 	int err = -EINVAL;
739 	struct sock *sk2 = sk1->sk_prot->accept(sk1, flags, &err, kern);
740 
741 	if (!sk2)
742 		goto do_err;
743 
744 	lock_sock(sk2);
745 
746 	sock_rps_record_flow(sk2);
747 	WARN_ON(!((1 << sk2->sk_state) &
748 		  (TCPF_ESTABLISHED | TCPF_SYN_RECV |
749 		  TCPF_CLOSE_WAIT | TCPF_CLOSE)));
750 
751 	sock_graft(sk2, newsock);
752 
753 	newsock->state = SS_CONNECTED;
754 	err = 0;
755 	release_sock(sk2);
756 do_err:
757 	return err;
758 }
759 EXPORT_SYMBOL(inet_accept);
760 
761 /*
762  *	This does both peername and sockname.
763  */
764 int inet_getname(struct socket *sock, struct sockaddr *uaddr,
765 		 int peer)
766 {
767 	struct sock *sk		= sock->sk;
768 	struct inet_sock *inet	= inet_sk(sk);
769 	DECLARE_SOCKADDR(struct sockaddr_in *, sin, uaddr);
770 
771 	sin->sin_family = AF_INET;
772 	lock_sock(sk);
773 	if (peer) {
774 		if (!inet->inet_dport ||
775 		    (((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_SYN_SENT)) &&
776 		     peer == 1)) {
777 			release_sock(sk);
778 			return -ENOTCONN;
779 		}
780 		sin->sin_port = inet->inet_dport;
781 		sin->sin_addr.s_addr = inet->inet_daddr;
782 		BPF_CGROUP_RUN_SA_PROG(sk, (struct sockaddr *)sin,
783 				       CGROUP_INET4_GETPEERNAME);
784 	} else {
785 		__be32 addr = inet->inet_rcv_saddr;
786 		if (!addr)
787 			addr = inet->inet_saddr;
788 		sin->sin_port = inet->inet_sport;
789 		sin->sin_addr.s_addr = addr;
790 		BPF_CGROUP_RUN_SA_PROG(sk, (struct sockaddr *)sin,
791 				       CGROUP_INET4_GETSOCKNAME);
792 	}
793 	release_sock(sk);
794 	memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
795 	return sizeof(*sin);
796 }
797 EXPORT_SYMBOL(inet_getname);
798 
799 int inet_send_prepare(struct sock *sk)
800 {
801 	sock_rps_record_flow(sk);
802 
803 	/* We may need to bind the socket. */
804 	if (data_race(!inet_sk(sk)->inet_num) && !sk->sk_prot->no_autobind &&
805 	    inet_autobind(sk))
806 		return -EAGAIN;
807 
808 	return 0;
809 }
810 EXPORT_SYMBOL_GPL(inet_send_prepare);
811 
812 int inet_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
813 {
814 	struct sock *sk = sock->sk;
815 
816 	if (unlikely(inet_send_prepare(sk)))
817 		return -EAGAIN;
818 
819 	return INDIRECT_CALL_2(sk->sk_prot->sendmsg, tcp_sendmsg, udp_sendmsg,
820 			       sk, msg, size);
821 }
822 EXPORT_SYMBOL(inet_sendmsg);
823 
824 ssize_t inet_sendpage(struct socket *sock, struct page *page, int offset,
825 		      size_t size, int flags)
826 {
827 	struct sock *sk = sock->sk;
828 
829 	if (unlikely(inet_send_prepare(sk)))
830 		return -EAGAIN;
831 
832 	if (sk->sk_prot->sendpage)
833 		return sk->sk_prot->sendpage(sk, page, offset, size, flags);
834 	return sock_no_sendpage(sock, page, offset, size, flags);
835 }
836 EXPORT_SYMBOL(inet_sendpage);
837 
838 INDIRECT_CALLABLE_DECLARE(int udp_recvmsg(struct sock *, struct msghdr *,
839 					  size_t, int, int, int *));
840 int inet_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
841 		 int flags)
842 {
843 	struct sock *sk = sock->sk;
844 	int addr_len = 0;
845 	int err;
846 
847 	if (likely(!(flags & MSG_ERRQUEUE)))
848 		sock_rps_record_flow(sk);
849 
850 	err = INDIRECT_CALL_2(sk->sk_prot->recvmsg, tcp_recvmsg, udp_recvmsg,
851 			      sk, msg, size, flags & MSG_DONTWAIT,
852 			      flags & ~MSG_DONTWAIT, &addr_len);
853 	if (err >= 0)
854 		msg->msg_namelen = addr_len;
855 	return err;
856 }
857 EXPORT_SYMBOL(inet_recvmsg);
858 
859 int inet_shutdown(struct socket *sock, int how)
860 {
861 	struct sock *sk = sock->sk;
862 	int err = 0;
863 
864 	/* This should really check to make sure
865 	 * the socket is a TCP socket. (WHY AC...)
866 	 */
867 	how++; /* maps 0->1 has the advantage of making bit 1 rcvs and
868 		       1->2 bit 2 snds.
869 		       2->3 */
870 	if ((how & ~SHUTDOWN_MASK) || !how)	/* MAXINT->0 */
871 		return -EINVAL;
872 
873 	lock_sock(sk);
874 	if (sock->state == SS_CONNECTING) {
875 		if ((1 << sk->sk_state) &
876 		    (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE))
877 			sock->state = SS_DISCONNECTING;
878 		else
879 			sock->state = SS_CONNECTED;
880 	}
881 
882 	switch (sk->sk_state) {
883 	case TCP_CLOSE:
884 		err = -ENOTCONN;
885 		/* Hack to wake up other listeners, who can poll for
886 		   EPOLLHUP, even on eg. unconnected UDP sockets -- RR */
887 		fallthrough;
888 	default:
889 		sk->sk_shutdown |= how;
890 		if (sk->sk_prot->shutdown)
891 			sk->sk_prot->shutdown(sk, how);
892 		break;
893 
894 	/* Remaining two branches are temporary solution for missing
895 	 * close() in multithreaded environment. It is _not_ a good idea,
896 	 * but we have no choice until close() is repaired at VFS level.
897 	 */
898 	case TCP_LISTEN:
899 		if (!(how & RCV_SHUTDOWN))
900 			break;
901 		fallthrough;
902 	case TCP_SYN_SENT:
903 		err = sk->sk_prot->disconnect(sk, O_NONBLOCK);
904 		sock->state = err ? SS_DISCONNECTING : SS_UNCONNECTED;
905 		break;
906 	}
907 
908 	/* Wake up anyone sleeping in poll. */
909 	sk->sk_state_change(sk);
910 	release_sock(sk);
911 	return err;
912 }
913 EXPORT_SYMBOL(inet_shutdown);
914 
915 /*
916  *	ioctl() calls you can issue on an INET socket. Most of these are
917  *	device configuration and stuff and very rarely used. Some ioctls
918  *	pass on to the socket itself.
919  *
920  *	NOTE: I like the idea of a module for the config stuff. ie ifconfig
921  *	loads the devconfigure module does its configuring and unloads it.
922  *	There's a good 20K of config code hanging around the kernel.
923  */
924 
925 int inet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
926 {
927 	struct sock *sk = sock->sk;
928 	int err = 0;
929 	struct net *net = sock_net(sk);
930 	void __user *p = (void __user *)arg;
931 	struct ifreq ifr;
932 	struct rtentry rt;
933 
934 	switch (cmd) {
935 	case SIOCADDRT:
936 	case SIOCDELRT:
937 		if (copy_from_user(&rt, p, sizeof(struct rtentry)))
938 			return -EFAULT;
939 		err = ip_rt_ioctl(net, cmd, &rt);
940 		break;
941 	case SIOCRTMSG:
942 		err = -EINVAL;
943 		break;
944 	case SIOCDARP:
945 	case SIOCGARP:
946 	case SIOCSARP:
947 		err = arp_ioctl(net, cmd, (void __user *)arg);
948 		break;
949 	case SIOCGIFADDR:
950 	case SIOCGIFBRDADDR:
951 	case SIOCGIFNETMASK:
952 	case SIOCGIFDSTADDR:
953 	case SIOCGIFPFLAGS:
954 		if (get_user_ifreq(&ifr, NULL, p))
955 			return -EFAULT;
956 		err = devinet_ioctl(net, cmd, &ifr);
957 		if (!err && put_user_ifreq(&ifr, p))
958 			err = -EFAULT;
959 		break;
960 
961 	case SIOCSIFADDR:
962 	case SIOCSIFBRDADDR:
963 	case SIOCSIFNETMASK:
964 	case SIOCSIFDSTADDR:
965 	case SIOCSIFPFLAGS:
966 	case SIOCSIFFLAGS:
967 		if (get_user_ifreq(&ifr, NULL, p))
968 			return -EFAULT;
969 		err = devinet_ioctl(net, cmd, &ifr);
970 		break;
971 	default:
972 		if (sk->sk_prot->ioctl)
973 			err = sk->sk_prot->ioctl(sk, cmd, arg);
974 		else
975 			err = -ENOIOCTLCMD;
976 		break;
977 	}
978 	return err;
979 }
980 EXPORT_SYMBOL(inet_ioctl);
981 
982 #ifdef CONFIG_COMPAT
983 static int inet_compat_routing_ioctl(struct sock *sk, unsigned int cmd,
984 		struct compat_rtentry __user *ur)
985 {
986 	compat_uptr_t rtdev;
987 	struct rtentry rt;
988 
989 	if (copy_from_user(&rt.rt_dst, &ur->rt_dst,
990 			3 * sizeof(struct sockaddr)) ||
991 	    get_user(rt.rt_flags, &ur->rt_flags) ||
992 	    get_user(rt.rt_metric, &ur->rt_metric) ||
993 	    get_user(rt.rt_mtu, &ur->rt_mtu) ||
994 	    get_user(rt.rt_window, &ur->rt_window) ||
995 	    get_user(rt.rt_irtt, &ur->rt_irtt) ||
996 	    get_user(rtdev, &ur->rt_dev))
997 		return -EFAULT;
998 
999 	rt.rt_dev = compat_ptr(rtdev);
1000 	return ip_rt_ioctl(sock_net(sk), cmd, &rt);
1001 }
1002 
1003 static int inet_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1004 {
1005 	void __user *argp = compat_ptr(arg);
1006 	struct sock *sk = sock->sk;
1007 
1008 	switch (cmd) {
1009 	case SIOCADDRT:
1010 	case SIOCDELRT:
1011 		return inet_compat_routing_ioctl(sk, cmd, argp);
1012 	default:
1013 		if (!sk->sk_prot->compat_ioctl)
1014 			return -ENOIOCTLCMD;
1015 		return sk->sk_prot->compat_ioctl(sk, cmd, arg);
1016 	}
1017 }
1018 #endif /* CONFIG_COMPAT */
1019 
1020 const struct proto_ops inet_stream_ops = {
1021 	.family		   = PF_INET,
1022 	.owner		   = THIS_MODULE,
1023 	.release	   = inet_release,
1024 	.bind		   = inet_bind,
1025 	.connect	   = inet_stream_connect,
1026 	.socketpair	   = sock_no_socketpair,
1027 	.accept		   = inet_accept,
1028 	.getname	   = inet_getname,
1029 	.poll		   = tcp_poll,
1030 	.ioctl		   = inet_ioctl,
1031 	.gettstamp	   = sock_gettstamp,
1032 	.listen		   = inet_listen,
1033 	.shutdown	   = inet_shutdown,
1034 	.setsockopt	   = sock_common_setsockopt,
1035 	.getsockopt	   = sock_common_getsockopt,
1036 	.sendmsg	   = inet_sendmsg,
1037 	.recvmsg	   = inet_recvmsg,
1038 #ifdef CONFIG_MMU
1039 	.mmap		   = tcp_mmap,
1040 #endif
1041 	.sendpage	   = inet_sendpage,
1042 	.splice_read	   = tcp_splice_read,
1043 	.read_sock	   = tcp_read_sock,
1044 	.sendmsg_locked    = tcp_sendmsg_locked,
1045 	.sendpage_locked   = tcp_sendpage_locked,
1046 	.peek_len	   = tcp_peek_len,
1047 #ifdef CONFIG_COMPAT
1048 	.compat_ioctl	   = inet_compat_ioctl,
1049 #endif
1050 	.set_rcvlowat	   = tcp_set_rcvlowat,
1051 };
1052 EXPORT_SYMBOL(inet_stream_ops);
1053 
1054 const struct proto_ops inet_dgram_ops = {
1055 	.family		   = PF_INET,
1056 	.owner		   = THIS_MODULE,
1057 	.release	   = inet_release,
1058 	.bind		   = inet_bind,
1059 	.connect	   = inet_dgram_connect,
1060 	.socketpair	   = sock_no_socketpair,
1061 	.accept		   = sock_no_accept,
1062 	.getname	   = inet_getname,
1063 	.poll		   = udp_poll,
1064 	.ioctl		   = inet_ioctl,
1065 	.gettstamp	   = sock_gettstamp,
1066 	.listen		   = sock_no_listen,
1067 	.shutdown	   = inet_shutdown,
1068 	.setsockopt	   = sock_common_setsockopt,
1069 	.getsockopt	   = sock_common_getsockopt,
1070 	.sendmsg	   = inet_sendmsg,
1071 	.read_sock	   = udp_read_sock,
1072 	.recvmsg	   = inet_recvmsg,
1073 	.mmap		   = sock_no_mmap,
1074 	.sendpage	   = inet_sendpage,
1075 	.set_peek_off	   = sk_set_peek_off,
1076 #ifdef CONFIG_COMPAT
1077 	.compat_ioctl	   = inet_compat_ioctl,
1078 #endif
1079 };
1080 EXPORT_SYMBOL(inet_dgram_ops);
1081 
1082 /*
1083  * For SOCK_RAW sockets; should be the same as inet_dgram_ops but without
1084  * udp_poll
1085  */
1086 static const struct proto_ops inet_sockraw_ops = {
1087 	.family		   = PF_INET,
1088 	.owner		   = THIS_MODULE,
1089 	.release	   = inet_release,
1090 	.bind		   = inet_bind,
1091 	.connect	   = inet_dgram_connect,
1092 	.socketpair	   = sock_no_socketpair,
1093 	.accept		   = sock_no_accept,
1094 	.getname	   = inet_getname,
1095 	.poll		   = datagram_poll,
1096 	.ioctl		   = inet_ioctl,
1097 	.gettstamp	   = sock_gettstamp,
1098 	.listen		   = sock_no_listen,
1099 	.shutdown	   = inet_shutdown,
1100 	.setsockopt	   = sock_common_setsockopt,
1101 	.getsockopt	   = sock_common_getsockopt,
1102 	.sendmsg	   = inet_sendmsg,
1103 	.recvmsg	   = inet_recvmsg,
1104 	.mmap		   = sock_no_mmap,
1105 	.sendpage	   = inet_sendpage,
1106 #ifdef CONFIG_COMPAT
1107 	.compat_ioctl	   = inet_compat_ioctl,
1108 #endif
1109 };
1110 
1111 static const struct net_proto_family inet_family_ops = {
1112 	.family = PF_INET,
1113 	.create = inet_create,
1114 	.owner	= THIS_MODULE,
1115 };
1116 
1117 /* Upon startup we insert all the elements in inetsw_array[] into
1118  * the linked list inetsw.
1119  */
1120 static struct inet_protosw inetsw_array[] =
1121 {
1122 	{
1123 		.type =       SOCK_STREAM,
1124 		.protocol =   IPPROTO_TCP,
1125 		.prot =       &tcp_prot,
1126 		.ops =        &inet_stream_ops,
1127 		.flags =      INET_PROTOSW_PERMANENT |
1128 			      INET_PROTOSW_ICSK,
1129 	},
1130 
1131 	{
1132 		.type =       SOCK_DGRAM,
1133 		.protocol =   IPPROTO_UDP,
1134 		.prot =       &udp_prot,
1135 		.ops =        &inet_dgram_ops,
1136 		.flags =      INET_PROTOSW_PERMANENT,
1137        },
1138 
1139        {
1140 		.type =       SOCK_DGRAM,
1141 		.protocol =   IPPROTO_ICMP,
1142 		.prot =       &ping_prot,
1143 		.ops =        &inet_sockraw_ops,
1144 		.flags =      INET_PROTOSW_REUSE,
1145        },
1146 
1147        {
1148 	       .type =       SOCK_RAW,
1149 	       .protocol =   IPPROTO_IP,	/* wild card */
1150 	       .prot =       &raw_prot,
1151 	       .ops =        &inet_sockraw_ops,
1152 	       .flags =      INET_PROTOSW_REUSE,
1153        }
1154 };
1155 
1156 #define INETSW_ARRAY_LEN ARRAY_SIZE(inetsw_array)
1157 
1158 void inet_register_protosw(struct inet_protosw *p)
1159 {
1160 	struct list_head *lh;
1161 	struct inet_protosw *answer;
1162 	int protocol = p->protocol;
1163 	struct list_head *last_perm;
1164 
1165 	spin_lock_bh(&inetsw_lock);
1166 
1167 	if (p->type >= SOCK_MAX)
1168 		goto out_illegal;
1169 
1170 	/* If we are trying to override a permanent protocol, bail. */
1171 	last_perm = &inetsw[p->type];
1172 	list_for_each(lh, &inetsw[p->type]) {
1173 		answer = list_entry(lh, struct inet_protosw, list);
1174 		/* Check only the non-wild match. */
1175 		if ((INET_PROTOSW_PERMANENT & answer->flags) == 0)
1176 			break;
1177 		if (protocol == answer->protocol)
1178 			goto out_permanent;
1179 		last_perm = lh;
1180 	}
1181 
1182 	/* Add the new entry after the last permanent entry if any, so that
1183 	 * the new entry does not override a permanent entry when matched with
1184 	 * a wild-card protocol. But it is allowed to override any existing
1185 	 * non-permanent entry.  This means that when we remove this entry, the
1186 	 * system automatically returns to the old behavior.
1187 	 */
1188 	list_add_rcu(&p->list, last_perm);
1189 out:
1190 	spin_unlock_bh(&inetsw_lock);
1191 
1192 	return;
1193 
1194 out_permanent:
1195 	pr_err("Attempt to override permanent protocol %d\n", protocol);
1196 	goto out;
1197 
1198 out_illegal:
1199 	pr_err("Ignoring attempt to register invalid socket type %d\n",
1200 	       p->type);
1201 	goto out;
1202 }
1203 EXPORT_SYMBOL(inet_register_protosw);
1204 
1205 void inet_unregister_protosw(struct inet_protosw *p)
1206 {
1207 	if (INET_PROTOSW_PERMANENT & p->flags) {
1208 		pr_err("Attempt to unregister permanent protocol %d\n",
1209 		       p->protocol);
1210 	} else {
1211 		spin_lock_bh(&inetsw_lock);
1212 		list_del_rcu(&p->list);
1213 		spin_unlock_bh(&inetsw_lock);
1214 
1215 		synchronize_net();
1216 	}
1217 }
1218 EXPORT_SYMBOL(inet_unregister_protosw);
1219 
1220 static int inet_sk_reselect_saddr(struct sock *sk)
1221 {
1222 	struct inet_sock *inet = inet_sk(sk);
1223 	__be32 old_saddr = inet->inet_saddr;
1224 	__be32 daddr = inet->inet_daddr;
1225 	struct flowi4 *fl4;
1226 	struct rtable *rt;
1227 	__be32 new_saddr;
1228 	struct ip_options_rcu *inet_opt;
1229 
1230 	inet_opt = rcu_dereference_protected(inet->inet_opt,
1231 					     lockdep_sock_is_held(sk));
1232 	if (inet_opt && inet_opt->opt.srr)
1233 		daddr = inet_opt->opt.faddr;
1234 
1235 	/* Query new route. */
1236 	fl4 = &inet->cork.fl.u.ip4;
1237 	rt = ip_route_connect(fl4, daddr, 0, RT_CONN_FLAGS(sk),
1238 			      sk->sk_bound_dev_if, sk->sk_protocol,
1239 			      inet->inet_sport, inet->inet_dport, sk);
1240 	if (IS_ERR(rt))
1241 		return PTR_ERR(rt);
1242 
1243 	sk_setup_caps(sk, &rt->dst);
1244 
1245 	new_saddr = fl4->saddr;
1246 
1247 	if (new_saddr == old_saddr)
1248 		return 0;
1249 
1250 	if (sock_net(sk)->ipv4.sysctl_ip_dynaddr > 1) {
1251 		pr_info("%s(): shifting inet->saddr from %pI4 to %pI4\n",
1252 			__func__, &old_saddr, &new_saddr);
1253 	}
1254 
1255 	inet->inet_saddr = inet->inet_rcv_saddr = new_saddr;
1256 
1257 	/*
1258 	 * XXX The only one ugly spot where we need to
1259 	 * XXX really change the sockets identity after
1260 	 * XXX it has entered the hashes. -DaveM
1261 	 *
1262 	 * Besides that, it does not check for connection
1263 	 * uniqueness. Wait for troubles.
1264 	 */
1265 	return __sk_prot_rehash(sk);
1266 }
1267 
1268 int inet_sk_rebuild_header(struct sock *sk)
1269 {
1270 	struct inet_sock *inet = inet_sk(sk);
1271 	struct rtable *rt = (struct rtable *)__sk_dst_check(sk, 0);
1272 	__be32 daddr;
1273 	struct ip_options_rcu *inet_opt;
1274 	struct flowi4 *fl4;
1275 	int err;
1276 
1277 	/* Route is OK, nothing to do. */
1278 	if (rt)
1279 		return 0;
1280 
1281 	/* Reroute. */
1282 	rcu_read_lock();
1283 	inet_opt = rcu_dereference(inet->inet_opt);
1284 	daddr = inet->inet_daddr;
1285 	if (inet_opt && inet_opt->opt.srr)
1286 		daddr = inet_opt->opt.faddr;
1287 	rcu_read_unlock();
1288 	fl4 = &inet->cork.fl.u.ip4;
1289 	rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr, inet->inet_saddr,
1290 				   inet->inet_dport, inet->inet_sport,
1291 				   sk->sk_protocol, RT_CONN_FLAGS(sk),
1292 				   sk->sk_bound_dev_if);
1293 	if (!IS_ERR(rt)) {
1294 		err = 0;
1295 		sk_setup_caps(sk, &rt->dst);
1296 	} else {
1297 		err = PTR_ERR(rt);
1298 
1299 		/* Routing failed... */
1300 		sk->sk_route_caps = 0;
1301 		/*
1302 		 * Other protocols have to map its equivalent state to TCP_SYN_SENT.
1303 		 * DCCP maps its DCCP_REQUESTING state to TCP_SYN_SENT. -acme
1304 		 */
1305 		if (!sock_net(sk)->ipv4.sysctl_ip_dynaddr ||
1306 		    sk->sk_state != TCP_SYN_SENT ||
1307 		    (sk->sk_userlocks & SOCK_BINDADDR_LOCK) ||
1308 		    (err = inet_sk_reselect_saddr(sk)) != 0)
1309 			sk->sk_err_soft = -err;
1310 	}
1311 
1312 	return err;
1313 }
1314 EXPORT_SYMBOL(inet_sk_rebuild_header);
1315 
1316 void inet_sk_set_state(struct sock *sk, int state)
1317 {
1318 	trace_inet_sock_set_state(sk, sk->sk_state, state);
1319 	sk->sk_state = state;
1320 }
1321 EXPORT_SYMBOL(inet_sk_set_state);
1322 
1323 void inet_sk_state_store(struct sock *sk, int newstate)
1324 {
1325 	trace_inet_sock_set_state(sk, sk->sk_state, newstate);
1326 	smp_store_release(&sk->sk_state, newstate);
1327 }
1328 
1329 struct sk_buff *inet_gso_segment(struct sk_buff *skb,
1330 				 netdev_features_t features)
1331 {
1332 	bool udpfrag = false, fixedid = false, gso_partial, encap;
1333 	struct sk_buff *segs = ERR_PTR(-EINVAL);
1334 	const struct net_offload *ops;
1335 	unsigned int offset = 0;
1336 	struct iphdr *iph;
1337 	int proto, tot_len;
1338 	int nhoff;
1339 	int ihl;
1340 	int id;
1341 
1342 	skb_reset_network_header(skb);
1343 	nhoff = skb_network_header(skb) - skb_mac_header(skb);
1344 	if (unlikely(!pskb_may_pull(skb, sizeof(*iph))))
1345 		goto out;
1346 
1347 	iph = ip_hdr(skb);
1348 	ihl = iph->ihl * 4;
1349 	if (ihl < sizeof(*iph))
1350 		goto out;
1351 
1352 	id = ntohs(iph->id);
1353 	proto = iph->protocol;
1354 
1355 	/* Warning: after this point, iph might be no longer valid */
1356 	if (unlikely(!pskb_may_pull(skb, ihl)))
1357 		goto out;
1358 	__skb_pull(skb, ihl);
1359 
1360 	encap = SKB_GSO_CB(skb)->encap_level > 0;
1361 	if (encap)
1362 		features &= skb->dev->hw_enc_features;
1363 	SKB_GSO_CB(skb)->encap_level += ihl;
1364 
1365 	skb_reset_transport_header(skb);
1366 
1367 	segs = ERR_PTR(-EPROTONOSUPPORT);
1368 
1369 	if (!skb->encapsulation || encap) {
1370 		udpfrag = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
1371 		fixedid = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TCP_FIXEDID);
1372 
1373 		/* fixed ID is invalid if DF bit is not set */
1374 		if (fixedid && !(ip_hdr(skb)->frag_off & htons(IP_DF)))
1375 			goto out;
1376 	}
1377 
1378 	ops = rcu_dereference(inet_offloads[proto]);
1379 	if (likely(ops && ops->callbacks.gso_segment)) {
1380 		segs = ops->callbacks.gso_segment(skb, features);
1381 		if (!segs)
1382 			skb->network_header = skb_mac_header(skb) + nhoff - skb->head;
1383 	}
1384 
1385 	if (IS_ERR_OR_NULL(segs))
1386 		goto out;
1387 
1388 	gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
1389 
1390 	skb = segs;
1391 	do {
1392 		iph = (struct iphdr *)(skb_mac_header(skb) + nhoff);
1393 		if (udpfrag) {
1394 			iph->frag_off = htons(offset >> 3);
1395 			if (skb->next)
1396 				iph->frag_off |= htons(IP_MF);
1397 			offset += skb->len - nhoff - ihl;
1398 			tot_len = skb->len - nhoff;
1399 		} else if (skb_is_gso(skb)) {
1400 			if (!fixedid) {
1401 				iph->id = htons(id);
1402 				id += skb_shinfo(skb)->gso_segs;
1403 			}
1404 
1405 			if (gso_partial)
1406 				tot_len = skb_shinfo(skb)->gso_size +
1407 					  SKB_GSO_CB(skb)->data_offset +
1408 					  skb->head - (unsigned char *)iph;
1409 			else
1410 				tot_len = skb->len - nhoff;
1411 		} else {
1412 			if (!fixedid)
1413 				iph->id = htons(id++);
1414 			tot_len = skb->len - nhoff;
1415 		}
1416 		iph->tot_len = htons(tot_len);
1417 		ip_send_check(iph);
1418 		if (encap)
1419 			skb_reset_inner_headers(skb);
1420 		skb->network_header = (u8 *)iph - skb->head;
1421 		skb_reset_mac_len(skb);
1422 	} while ((skb = skb->next));
1423 
1424 out:
1425 	return segs;
1426 }
1427 
1428 static struct sk_buff *ipip_gso_segment(struct sk_buff *skb,
1429 					netdev_features_t features)
1430 {
1431 	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4))
1432 		return ERR_PTR(-EINVAL);
1433 
1434 	return inet_gso_segment(skb, features);
1435 }
1436 
1437 struct sk_buff *inet_gro_receive(struct list_head *head, struct sk_buff *skb)
1438 {
1439 	const struct net_offload *ops;
1440 	struct sk_buff *pp = NULL;
1441 	const struct iphdr *iph;
1442 	struct sk_buff *p;
1443 	unsigned int hlen;
1444 	unsigned int off;
1445 	unsigned int id;
1446 	int flush = 1;
1447 	int proto;
1448 
1449 	off = skb_gro_offset(skb);
1450 	hlen = off + sizeof(*iph);
1451 	iph = skb_gro_header_fast(skb, off);
1452 	if (skb_gro_header_hard(skb, hlen)) {
1453 		iph = skb_gro_header_slow(skb, hlen, off);
1454 		if (unlikely(!iph))
1455 			goto out;
1456 	}
1457 
1458 	proto = iph->protocol;
1459 
1460 	ops = rcu_dereference(inet_offloads[proto]);
1461 	if (!ops || !ops->callbacks.gro_receive)
1462 		goto out;
1463 
1464 	if (*(u8 *)iph != 0x45)
1465 		goto out;
1466 
1467 	if (ip_is_fragment(iph))
1468 		goto out;
1469 
1470 	if (unlikely(ip_fast_csum((u8 *)iph, 5)))
1471 		goto out;
1472 
1473 	id = ntohl(*(__be32 *)&iph->id);
1474 	flush = (u16)((ntohl(*(__be32 *)iph) ^ skb_gro_len(skb)) | (id & ~IP_DF));
1475 	id >>= 16;
1476 
1477 	list_for_each_entry(p, head, list) {
1478 		struct iphdr *iph2;
1479 		u16 flush_id;
1480 
1481 		if (!NAPI_GRO_CB(p)->same_flow)
1482 			continue;
1483 
1484 		iph2 = (struct iphdr *)(p->data + off);
1485 		/* The above works because, with the exception of the top
1486 		 * (inner most) layer, we only aggregate pkts with the same
1487 		 * hdr length so all the hdrs we'll need to verify will start
1488 		 * at the same offset.
1489 		 */
1490 		if ((iph->protocol ^ iph2->protocol) |
1491 		    ((__force u32)iph->saddr ^ (__force u32)iph2->saddr) |
1492 		    ((__force u32)iph->daddr ^ (__force u32)iph2->daddr)) {
1493 			NAPI_GRO_CB(p)->same_flow = 0;
1494 			continue;
1495 		}
1496 
1497 		/* All fields must match except length and checksum. */
1498 		NAPI_GRO_CB(p)->flush |=
1499 			(iph->ttl ^ iph2->ttl) |
1500 			(iph->tos ^ iph2->tos) |
1501 			((iph->frag_off ^ iph2->frag_off) & htons(IP_DF));
1502 
1503 		NAPI_GRO_CB(p)->flush |= flush;
1504 
1505 		/* We need to store of the IP ID check to be included later
1506 		 * when we can verify that this packet does in fact belong
1507 		 * to a given flow.
1508 		 */
1509 		flush_id = (u16)(id - ntohs(iph2->id));
1510 
1511 		/* This bit of code makes it much easier for us to identify
1512 		 * the cases where we are doing atomic vs non-atomic IP ID
1513 		 * checks.  Specifically an atomic check can return IP ID
1514 		 * values 0 - 0xFFFF, while a non-atomic check can only
1515 		 * return 0 or 0xFFFF.
1516 		 */
1517 		if (!NAPI_GRO_CB(p)->is_atomic ||
1518 		    !(iph->frag_off & htons(IP_DF))) {
1519 			flush_id ^= NAPI_GRO_CB(p)->count;
1520 			flush_id = flush_id ? 0xFFFF : 0;
1521 		}
1522 
1523 		/* If the previous IP ID value was based on an atomic
1524 		 * datagram we can overwrite the value and ignore it.
1525 		 */
1526 		if (NAPI_GRO_CB(skb)->is_atomic)
1527 			NAPI_GRO_CB(p)->flush_id = flush_id;
1528 		else
1529 			NAPI_GRO_CB(p)->flush_id |= flush_id;
1530 	}
1531 
1532 	NAPI_GRO_CB(skb)->is_atomic = !!(iph->frag_off & htons(IP_DF));
1533 	NAPI_GRO_CB(skb)->flush |= flush;
1534 	skb_set_network_header(skb, off);
1535 	/* The above will be needed by the transport layer if there is one
1536 	 * immediately following this IP hdr.
1537 	 */
1538 
1539 	/* Note : No need to call skb_gro_postpull_rcsum() here,
1540 	 * as we already checked checksum over ipv4 header was 0
1541 	 */
1542 	skb_gro_pull(skb, sizeof(*iph));
1543 	skb_set_transport_header(skb, skb_gro_offset(skb));
1544 
1545 	pp = indirect_call_gro_receive(tcp4_gro_receive, udp4_gro_receive,
1546 				       ops->callbacks.gro_receive, head, skb);
1547 
1548 out:
1549 	skb_gro_flush_final(skb, pp, flush);
1550 
1551 	return pp;
1552 }
1553 
1554 static struct sk_buff *ipip_gro_receive(struct list_head *head,
1555 					struct sk_buff *skb)
1556 {
1557 	if (NAPI_GRO_CB(skb)->encap_mark) {
1558 		NAPI_GRO_CB(skb)->flush = 1;
1559 		return NULL;
1560 	}
1561 
1562 	NAPI_GRO_CB(skb)->encap_mark = 1;
1563 
1564 	return inet_gro_receive(head, skb);
1565 }
1566 
1567 #define SECONDS_PER_DAY	86400
1568 
1569 /* inet_current_timestamp - Return IP network timestamp
1570  *
1571  * Return milliseconds since midnight in network byte order.
1572  */
1573 __be32 inet_current_timestamp(void)
1574 {
1575 	u32 secs;
1576 	u32 msecs;
1577 	struct timespec64 ts;
1578 
1579 	ktime_get_real_ts64(&ts);
1580 
1581 	/* Get secs since midnight. */
1582 	(void)div_u64_rem(ts.tv_sec, SECONDS_PER_DAY, &secs);
1583 	/* Convert to msecs. */
1584 	msecs = secs * MSEC_PER_SEC;
1585 	/* Convert nsec to msec. */
1586 	msecs += (u32)ts.tv_nsec / NSEC_PER_MSEC;
1587 
1588 	/* Convert to network byte order. */
1589 	return htonl(msecs);
1590 }
1591 EXPORT_SYMBOL(inet_current_timestamp);
1592 
1593 int inet_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
1594 {
1595 	if (sk->sk_family == AF_INET)
1596 		return ip_recv_error(sk, msg, len, addr_len);
1597 #if IS_ENABLED(CONFIG_IPV6)
1598 	if (sk->sk_family == AF_INET6)
1599 		return pingv6_ops.ipv6_recv_error(sk, msg, len, addr_len);
1600 #endif
1601 	return -EINVAL;
1602 }
1603 
1604 int inet_gro_complete(struct sk_buff *skb, int nhoff)
1605 {
1606 	__be16 newlen = htons(skb->len - nhoff);
1607 	struct iphdr *iph = (struct iphdr *)(skb->data + nhoff);
1608 	const struct net_offload *ops;
1609 	int proto = iph->protocol;
1610 	int err = -ENOSYS;
1611 
1612 	if (skb->encapsulation) {
1613 		skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IP));
1614 		skb_set_inner_network_header(skb, nhoff);
1615 	}
1616 
1617 	csum_replace2(&iph->check, iph->tot_len, newlen);
1618 	iph->tot_len = newlen;
1619 
1620 	ops = rcu_dereference(inet_offloads[proto]);
1621 	if (WARN_ON(!ops || !ops->callbacks.gro_complete))
1622 		goto out;
1623 
1624 	/* Only need to add sizeof(*iph) to get to the next hdr below
1625 	 * because any hdr with option will have been flushed in
1626 	 * inet_gro_receive().
1627 	 */
1628 	err = INDIRECT_CALL_2(ops->callbacks.gro_complete,
1629 			      tcp4_gro_complete, udp4_gro_complete,
1630 			      skb, nhoff + sizeof(*iph));
1631 
1632 out:
1633 	return err;
1634 }
1635 
1636 static int ipip_gro_complete(struct sk_buff *skb, int nhoff)
1637 {
1638 	skb->encapsulation = 1;
1639 	skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
1640 	return inet_gro_complete(skb, nhoff);
1641 }
1642 
1643 int inet_ctl_sock_create(struct sock **sk, unsigned short family,
1644 			 unsigned short type, unsigned char protocol,
1645 			 struct net *net)
1646 {
1647 	struct socket *sock;
1648 	int rc = sock_create_kern(net, family, type, protocol, &sock);
1649 
1650 	if (rc == 0) {
1651 		*sk = sock->sk;
1652 		(*sk)->sk_allocation = GFP_ATOMIC;
1653 		/*
1654 		 * Unhash it so that IP input processing does not even see it,
1655 		 * we do not wish this socket to see incoming packets.
1656 		 */
1657 		(*sk)->sk_prot->unhash(*sk);
1658 	}
1659 	return rc;
1660 }
1661 EXPORT_SYMBOL_GPL(inet_ctl_sock_create);
1662 
1663 unsigned long snmp_fold_field(void __percpu *mib, int offt)
1664 {
1665 	unsigned long res = 0;
1666 	int i;
1667 
1668 	for_each_possible_cpu(i)
1669 		res += snmp_get_cpu_field(mib, i, offt);
1670 	return res;
1671 }
1672 EXPORT_SYMBOL_GPL(snmp_fold_field);
1673 
1674 #if BITS_PER_LONG==32
1675 
1676 u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offt,
1677 			 size_t syncp_offset)
1678 {
1679 	void *bhptr;
1680 	struct u64_stats_sync *syncp;
1681 	u64 v;
1682 	unsigned int start;
1683 
1684 	bhptr = per_cpu_ptr(mib, cpu);
1685 	syncp = (struct u64_stats_sync *)(bhptr + syncp_offset);
1686 	do {
1687 		start = u64_stats_fetch_begin_irq(syncp);
1688 		v = *(((u64 *)bhptr) + offt);
1689 	} while (u64_stats_fetch_retry_irq(syncp, start));
1690 
1691 	return v;
1692 }
1693 EXPORT_SYMBOL_GPL(snmp_get_cpu_field64);
1694 
1695 u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_offset)
1696 {
1697 	u64 res = 0;
1698 	int cpu;
1699 
1700 	for_each_possible_cpu(cpu) {
1701 		res += snmp_get_cpu_field64(mib, cpu, offt, syncp_offset);
1702 	}
1703 	return res;
1704 }
1705 EXPORT_SYMBOL_GPL(snmp_fold_field64);
1706 #endif
1707 
1708 #ifdef CONFIG_IP_MULTICAST
1709 static const struct net_protocol igmp_protocol = {
1710 	.handler =	igmp_rcv,
1711 };
1712 #endif
1713 
1714 /* thinking of making this const? Don't.
1715  * early_demux can change based on sysctl.
1716  */
1717 static struct net_protocol tcp_protocol = {
1718 	.early_demux	=	tcp_v4_early_demux,
1719 	.early_demux_handler =  tcp_v4_early_demux,
1720 	.handler	=	tcp_v4_rcv,
1721 	.err_handler	=	tcp_v4_err,
1722 	.no_policy	=	1,
1723 	.icmp_strict_tag_validation = 1,
1724 };
1725 
1726 /* thinking of making this const? Don't.
1727  * early_demux can change based on sysctl.
1728  */
1729 static struct net_protocol udp_protocol = {
1730 	.early_demux =	udp_v4_early_demux,
1731 	.early_demux_handler =	udp_v4_early_demux,
1732 	.handler =	udp_rcv,
1733 	.err_handler =	udp_err,
1734 	.no_policy =	1,
1735 };
1736 
1737 static const struct net_protocol icmp_protocol = {
1738 	.handler =	icmp_rcv,
1739 	.err_handler =	icmp_err,
1740 	.no_policy =	1,
1741 };
1742 
1743 static __net_init int ipv4_mib_init_net(struct net *net)
1744 {
1745 	int i;
1746 
1747 	net->mib.tcp_statistics = alloc_percpu(struct tcp_mib);
1748 	if (!net->mib.tcp_statistics)
1749 		goto err_tcp_mib;
1750 	net->mib.ip_statistics = alloc_percpu(struct ipstats_mib);
1751 	if (!net->mib.ip_statistics)
1752 		goto err_ip_mib;
1753 
1754 	for_each_possible_cpu(i) {
1755 		struct ipstats_mib *af_inet_stats;
1756 		af_inet_stats = per_cpu_ptr(net->mib.ip_statistics, i);
1757 		u64_stats_init(&af_inet_stats->syncp);
1758 	}
1759 
1760 	net->mib.net_statistics = alloc_percpu(struct linux_mib);
1761 	if (!net->mib.net_statistics)
1762 		goto err_net_mib;
1763 	net->mib.udp_statistics = alloc_percpu(struct udp_mib);
1764 	if (!net->mib.udp_statistics)
1765 		goto err_udp_mib;
1766 	net->mib.udplite_statistics = alloc_percpu(struct udp_mib);
1767 	if (!net->mib.udplite_statistics)
1768 		goto err_udplite_mib;
1769 	net->mib.icmp_statistics = alloc_percpu(struct icmp_mib);
1770 	if (!net->mib.icmp_statistics)
1771 		goto err_icmp_mib;
1772 	net->mib.icmpmsg_statistics = kzalloc(sizeof(struct icmpmsg_mib),
1773 					      GFP_KERNEL);
1774 	if (!net->mib.icmpmsg_statistics)
1775 		goto err_icmpmsg_mib;
1776 
1777 	tcp_mib_init(net);
1778 	return 0;
1779 
1780 err_icmpmsg_mib:
1781 	free_percpu(net->mib.icmp_statistics);
1782 err_icmp_mib:
1783 	free_percpu(net->mib.udplite_statistics);
1784 err_udplite_mib:
1785 	free_percpu(net->mib.udp_statistics);
1786 err_udp_mib:
1787 	free_percpu(net->mib.net_statistics);
1788 err_net_mib:
1789 	free_percpu(net->mib.ip_statistics);
1790 err_ip_mib:
1791 	free_percpu(net->mib.tcp_statistics);
1792 err_tcp_mib:
1793 	return -ENOMEM;
1794 }
1795 
1796 static __net_exit void ipv4_mib_exit_net(struct net *net)
1797 {
1798 	kfree(net->mib.icmpmsg_statistics);
1799 	free_percpu(net->mib.icmp_statistics);
1800 	free_percpu(net->mib.udplite_statistics);
1801 	free_percpu(net->mib.udp_statistics);
1802 	free_percpu(net->mib.net_statistics);
1803 	free_percpu(net->mib.ip_statistics);
1804 	free_percpu(net->mib.tcp_statistics);
1805 #ifdef CONFIG_MPTCP
1806 	/* allocated on demand, see mptcp_init_sock() */
1807 	free_percpu(net->mib.mptcp_statistics);
1808 #endif
1809 }
1810 
1811 static __net_initdata struct pernet_operations ipv4_mib_ops = {
1812 	.init = ipv4_mib_init_net,
1813 	.exit = ipv4_mib_exit_net,
1814 };
1815 
1816 static int __init init_ipv4_mibs(void)
1817 {
1818 	return register_pernet_subsys(&ipv4_mib_ops);
1819 }
1820 
1821 static __net_init int inet_init_net(struct net *net)
1822 {
1823 	/*
1824 	 * Set defaults for local port range
1825 	 */
1826 	seqlock_init(&net->ipv4.ip_local_ports.lock);
1827 	net->ipv4.ip_local_ports.range[0] =  32768;
1828 	net->ipv4.ip_local_ports.range[1] =  60999;
1829 
1830 	seqlock_init(&net->ipv4.ping_group_range.lock);
1831 	/*
1832 	 * Sane defaults - nobody may create ping sockets.
1833 	 * Boot scripts should set this to distro-specific group.
1834 	 */
1835 	net->ipv4.ping_group_range.range[0] = make_kgid(&init_user_ns, 1);
1836 	net->ipv4.ping_group_range.range[1] = make_kgid(&init_user_ns, 0);
1837 
1838 	/* Default values for sysctl-controlled parameters.
1839 	 * We set them here, in case sysctl is not compiled.
1840 	 */
1841 	net->ipv4.sysctl_ip_default_ttl = IPDEFTTL;
1842 	net->ipv4.sysctl_ip_fwd_update_priority = 1;
1843 	net->ipv4.sysctl_ip_dynaddr = 0;
1844 	net->ipv4.sysctl_ip_early_demux = 1;
1845 	net->ipv4.sysctl_udp_early_demux = 1;
1846 	net->ipv4.sysctl_tcp_early_demux = 1;
1847 	net->ipv4.sysctl_nexthop_compat_mode = 1;
1848 #ifdef CONFIG_SYSCTL
1849 	net->ipv4.sysctl_ip_prot_sock = PROT_SOCK;
1850 #endif
1851 
1852 	/* Some igmp sysctl, whose values are always used */
1853 	net->ipv4.sysctl_igmp_max_memberships = 20;
1854 	net->ipv4.sysctl_igmp_max_msf = 10;
1855 	/* IGMP reports for link-local multicast groups are enabled by default */
1856 	net->ipv4.sysctl_igmp_llm_reports = 1;
1857 	net->ipv4.sysctl_igmp_qrv = 2;
1858 
1859 	net->ipv4.sysctl_fib_notify_on_flag_change = 0;
1860 
1861 	return 0;
1862 }
1863 
1864 static __net_initdata struct pernet_operations af_inet_ops = {
1865 	.init = inet_init_net,
1866 };
1867 
1868 static int __init init_inet_pernet_ops(void)
1869 {
1870 	return register_pernet_subsys(&af_inet_ops);
1871 }
1872 
1873 static int ipv4_proc_init(void);
1874 
1875 /*
1876  *	IP protocol layer initialiser
1877  */
1878 
1879 static struct packet_offload ip_packet_offload __read_mostly = {
1880 	.type = cpu_to_be16(ETH_P_IP),
1881 	.callbacks = {
1882 		.gso_segment = inet_gso_segment,
1883 		.gro_receive = inet_gro_receive,
1884 		.gro_complete = inet_gro_complete,
1885 	},
1886 };
1887 
1888 static const struct net_offload ipip_offload = {
1889 	.callbacks = {
1890 		.gso_segment	= ipip_gso_segment,
1891 		.gro_receive	= ipip_gro_receive,
1892 		.gro_complete	= ipip_gro_complete,
1893 	},
1894 };
1895 
1896 static int __init ipip_offload_init(void)
1897 {
1898 	return inet_add_offload(&ipip_offload, IPPROTO_IPIP);
1899 }
1900 
1901 static int __init ipv4_offload_init(void)
1902 {
1903 	/*
1904 	 * Add offloads
1905 	 */
1906 	if (udpv4_offload_init() < 0)
1907 		pr_crit("%s: Cannot add UDP protocol offload\n", __func__);
1908 	if (tcpv4_offload_init() < 0)
1909 		pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
1910 	if (ipip_offload_init() < 0)
1911 		pr_crit("%s: Cannot add IPIP protocol offload\n", __func__);
1912 
1913 	dev_add_offload(&ip_packet_offload);
1914 	return 0;
1915 }
1916 
1917 fs_initcall(ipv4_offload_init);
1918 
1919 static struct packet_type ip_packet_type __read_mostly = {
1920 	.type = cpu_to_be16(ETH_P_IP),
1921 	.func = ip_rcv,
1922 	.list_func = ip_list_rcv,
1923 };
1924 
1925 static int __init inet_init(void)
1926 {
1927 	struct inet_protosw *q;
1928 	struct list_head *r;
1929 	int rc;
1930 
1931 	sock_skb_cb_check_size(sizeof(struct inet_skb_parm));
1932 
1933 	rc = proto_register(&tcp_prot, 1);
1934 	if (rc)
1935 		goto out;
1936 
1937 	rc = proto_register(&udp_prot, 1);
1938 	if (rc)
1939 		goto out_unregister_tcp_proto;
1940 
1941 	rc = proto_register(&raw_prot, 1);
1942 	if (rc)
1943 		goto out_unregister_udp_proto;
1944 
1945 	rc = proto_register(&ping_prot, 1);
1946 	if (rc)
1947 		goto out_unregister_raw_proto;
1948 
1949 	/*
1950 	 *	Tell SOCKET that we are alive...
1951 	 */
1952 
1953 	(void)sock_register(&inet_family_ops);
1954 
1955 #ifdef CONFIG_SYSCTL
1956 	ip_static_sysctl_init();
1957 #endif
1958 
1959 	/*
1960 	 *	Add all the base protocols.
1961 	 */
1962 
1963 	if (inet_add_protocol(&icmp_protocol, IPPROTO_ICMP) < 0)
1964 		pr_crit("%s: Cannot add ICMP protocol\n", __func__);
1965 	if (inet_add_protocol(&udp_protocol, IPPROTO_UDP) < 0)
1966 		pr_crit("%s: Cannot add UDP protocol\n", __func__);
1967 	if (inet_add_protocol(&tcp_protocol, IPPROTO_TCP) < 0)
1968 		pr_crit("%s: Cannot add TCP protocol\n", __func__);
1969 #ifdef CONFIG_IP_MULTICAST
1970 	if (inet_add_protocol(&igmp_protocol, IPPROTO_IGMP) < 0)
1971 		pr_crit("%s: Cannot add IGMP protocol\n", __func__);
1972 #endif
1973 
1974 	/* Register the socket-side information for inet_create. */
1975 	for (r = &inetsw[0]; r < &inetsw[SOCK_MAX]; ++r)
1976 		INIT_LIST_HEAD(r);
1977 
1978 	for (q = inetsw_array; q < &inetsw_array[INETSW_ARRAY_LEN]; ++q)
1979 		inet_register_protosw(q);
1980 
1981 	/*
1982 	 *	Set the ARP module up
1983 	 */
1984 
1985 	arp_init();
1986 
1987 	/*
1988 	 *	Set the IP module up
1989 	 */
1990 
1991 	ip_init();
1992 
1993 	/* Initialise per-cpu ipv4 mibs */
1994 	if (init_ipv4_mibs())
1995 		panic("%s: Cannot init ipv4 mibs\n", __func__);
1996 
1997 	/* Setup TCP slab cache for open requests. */
1998 	tcp_init();
1999 
2000 	/* Setup UDP memory threshold */
2001 	udp_init();
2002 
2003 	/* Add UDP-Lite (RFC 3828) */
2004 	udplite4_register();
2005 
2006 	raw_init();
2007 
2008 	ping_init();
2009 
2010 	/*
2011 	 *	Set the ICMP layer up
2012 	 */
2013 
2014 	if (icmp_init() < 0)
2015 		panic("Failed to create the ICMP control socket.\n");
2016 
2017 	/*
2018 	 *	Initialise the multicast router
2019 	 */
2020 #if defined(CONFIG_IP_MROUTE)
2021 	if (ip_mr_init())
2022 		pr_crit("%s: Cannot init ipv4 mroute\n", __func__);
2023 #endif
2024 
2025 	if (init_inet_pernet_ops())
2026 		pr_crit("%s: Cannot init ipv4 inet pernet ops\n", __func__);
2027 
2028 	ipv4_proc_init();
2029 
2030 	ipfrag_init();
2031 
2032 	dev_add_pack(&ip_packet_type);
2033 
2034 	ip_tunnel_core_init();
2035 
2036 	rc = 0;
2037 out:
2038 	return rc;
2039 out_unregister_raw_proto:
2040 	proto_unregister(&raw_prot);
2041 out_unregister_udp_proto:
2042 	proto_unregister(&udp_prot);
2043 out_unregister_tcp_proto:
2044 	proto_unregister(&tcp_prot);
2045 	goto out;
2046 }
2047 
2048 fs_initcall(inet_init);
2049 
2050 /* ------------------------------------------------------------------------ */
2051 
2052 #ifdef CONFIG_PROC_FS
2053 static int __init ipv4_proc_init(void)
2054 {
2055 	int rc = 0;
2056 
2057 	if (raw_proc_init())
2058 		goto out_raw;
2059 	if (tcp4_proc_init())
2060 		goto out_tcp;
2061 	if (udp4_proc_init())
2062 		goto out_udp;
2063 	if (ping_proc_init())
2064 		goto out_ping;
2065 	if (ip_misc_proc_init())
2066 		goto out_misc;
2067 out:
2068 	return rc;
2069 out_misc:
2070 	ping_proc_exit();
2071 out_ping:
2072 	udp4_proc_exit();
2073 out_udp:
2074 	tcp4_proc_exit();
2075 out_tcp:
2076 	raw_proc_exit();
2077 out_raw:
2078 	rc = -ENOMEM;
2079 	goto out;
2080 }
2081 
2082 #else /* CONFIG_PROC_FS */
2083 static int __init ipv4_proc_init(void)
2084 {
2085 	return 0;
2086 }
2087 #endif /* CONFIG_PROC_FS */
2088