xref: /linux/net/ipv4/af_inet.c (revision ca853314e78b0a65c20b6a889a23c31f918d4aa2)
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/tcp.h>
103 #include <net/udp.h>
104 #include <net/udplite.h>
105 #include <net/ping.h>
106 #include <linux/skbuff.h>
107 #include <net/sock.h>
108 #include <net/raw.h>
109 #include <net/icmp.h>
110 #include <net/inet_common.h>
111 #include <net/ip_tunnels.h>
112 #include <net/xfrm.h>
113 #include <net/net_namespace.h>
114 #include <net/secure_seq.h>
115 #ifdef CONFIG_IP_MROUTE
116 #include <linux/mroute.h>
117 #endif
118 #include <net/l3mdev.h>
119 #include <net/compat.h>
120 
121 #include <trace/events/sock.h>
122 
123 /* The inetsw table contains everything that inet_create needs to
124  * build a new socket.
125  */
126 static struct list_head inetsw[SOCK_MAX];
127 static DEFINE_SPINLOCK(inetsw_lock);
128 
129 /* New destruction routine */
130 
131 void inet_sock_destruct(struct sock *sk)
132 {
133 	struct inet_sock *inet = inet_sk(sk);
134 
135 	__skb_queue_purge(&sk->sk_receive_queue);
136 	if (sk->sk_rx_skb_cache) {
137 		__kfree_skb(sk->sk_rx_skb_cache);
138 		sk->sk_rx_skb_cache = NULL;
139 	}
140 	__skb_queue_purge(&sk->sk_error_queue);
141 
142 	sk_mem_reclaim(sk);
143 
144 	if (sk->sk_type == SOCK_STREAM && sk->sk_state != TCP_CLOSE) {
145 		pr_err("Attempt to release TCP socket in state %d %p\n",
146 		       sk->sk_state, sk);
147 		return;
148 	}
149 	if (!sock_flag(sk, SOCK_DEAD)) {
150 		pr_err("Attempt to release alive inet socket %p\n", sk);
151 		return;
152 	}
153 
154 	WARN_ON(atomic_read(&sk->sk_rmem_alloc));
155 	WARN_ON(refcount_read(&sk->sk_wmem_alloc));
156 	WARN_ON(sk->sk_wmem_queued);
157 	WARN_ON(sk->sk_forward_alloc);
158 
159 	kfree(rcu_dereference_protected(inet->inet_opt, 1));
160 	dst_release(rcu_dereference_protected(sk->sk_dst_cache, 1));
161 	dst_release(sk->sk_rx_dst);
162 	sk_refcnt_debug_dec(sk);
163 }
164 EXPORT_SYMBOL(inet_sock_destruct);
165 
166 /*
167  *	The routines beyond this point handle the behaviour of an AF_INET
168  *	socket object. Mostly it punts to the subprotocols of IP to do
169  *	the work.
170  */
171 
172 /*
173  *	Automatically bind an unbound socket.
174  */
175 
176 static int inet_autobind(struct sock *sk)
177 {
178 	struct inet_sock *inet;
179 	/* We may need to bind the socket. */
180 	lock_sock(sk);
181 	inet = inet_sk(sk);
182 	if (!inet->inet_num) {
183 		if (sk->sk_prot->get_port(sk, 0)) {
184 			release_sock(sk);
185 			return -EAGAIN;
186 		}
187 		inet->inet_sport = htons(inet->inet_num);
188 	}
189 	release_sock(sk);
190 	return 0;
191 }
192 
193 /*
194  *	Move a socket into listening state.
195  */
196 int inet_listen(struct socket *sock, int backlog)
197 {
198 	struct sock *sk = sock->sk;
199 	unsigned char old_state;
200 	int err, tcp_fastopen;
201 
202 	lock_sock(sk);
203 
204 	err = -EINVAL;
205 	if (sock->state != SS_UNCONNECTED || sock->type != SOCK_STREAM)
206 		goto out;
207 
208 	old_state = sk->sk_state;
209 	if (!((1 << old_state) & (TCPF_CLOSE | TCPF_LISTEN)))
210 		goto out;
211 
212 	WRITE_ONCE(sk->sk_max_ack_backlog, backlog);
213 	/* Really, if the socket is already in listen state
214 	 * we can only allow the backlog to be adjusted.
215 	 */
216 	if (old_state != TCP_LISTEN) {
217 		/* Enable TFO w/o requiring TCP_FASTOPEN socket option.
218 		 * Note that only TCP sockets (SOCK_STREAM) will reach here.
219 		 * Also fastopen backlog may already been set via the option
220 		 * because the socket was in TCP_LISTEN state previously but
221 		 * was shutdown() rather than close().
222 		 */
223 		tcp_fastopen = sock_net(sk)->ipv4.sysctl_tcp_fastopen;
224 		if ((tcp_fastopen & TFO_SERVER_WO_SOCKOPT1) &&
225 		    (tcp_fastopen & TFO_SERVER_ENABLE) &&
226 		    !inet_csk(sk)->icsk_accept_queue.fastopenq.max_qlen) {
227 			fastopen_queue_tune(sk, backlog);
228 			tcp_fastopen_init_key_once(sock_net(sk));
229 		}
230 
231 		err = inet_csk_listen_start(sk, backlog);
232 		if (err)
233 			goto out;
234 		tcp_call_bpf(sk, BPF_SOCK_OPS_TCP_LISTEN_CB, 0, NULL);
235 	}
236 	err = 0;
237 
238 out:
239 	release_sock(sk);
240 	return err;
241 }
242 EXPORT_SYMBOL(inet_listen);
243 
244 /*
245  *	Create an inet socket.
246  */
247 
248 static int inet_create(struct net *net, struct socket *sock, int protocol,
249 		       int kern)
250 {
251 	struct sock *sk;
252 	struct inet_protosw *answer;
253 	struct inet_sock *inet;
254 	struct proto *answer_prot;
255 	unsigned char answer_flags;
256 	int try_loading_module = 0;
257 	int err;
258 
259 	if (protocol < 0 || protocol >= IPPROTO_MAX)
260 		return -EINVAL;
261 
262 	sock->state = SS_UNCONNECTED;
263 
264 	/* Look for the requested type/protocol pair. */
265 lookup_protocol:
266 	err = -ESOCKTNOSUPPORT;
267 	rcu_read_lock();
268 	list_for_each_entry_rcu(answer, &inetsw[sock->type], list) {
269 
270 		err = 0;
271 		/* Check the non-wild match. */
272 		if (protocol == answer->protocol) {
273 			if (protocol != IPPROTO_IP)
274 				break;
275 		} else {
276 			/* Check for the two wild cases. */
277 			if (IPPROTO_IP == protocol) {
278 				protocol = answer->protocol;
279 				break;
280 			}
281 			if (IPPROTO_IP == answer->protocol)
282 				break;
283 		}
284 		err = -EPROTONOSUPPORT;
285 	}
286 
287 	if (unlikely(err)) {
288 		if (try_loading_module < 2) {
289 			rcu_read_unlock();
290 			/*
291 			 * Be more specific, e.g. net-pf-2-proto-132-type-1
292 			 * (net-pf-PF_INET-proto-IPPROTO_SCTP-type-SOCK_STREAM)
293 			 */
294 			if (++try_loading_module == 1)
295 				request_module("net-pf-%d-proto-%d-type-%d",
296 					       PF_INET, protocol, sock->type);
297 			/*
298 			 * Fall back to generic, e.g. net-pf-2-proto-132
299 			 * (net-pf-PF_INET-proto-IPPROTO_SCTP)
300 			 */
301 			else
302 				request_module("net-pf-%d-proto-%d",
303 					       PF_INET, protocol);
304 			goto lookup_protocol;
305 		} else
306 			goto out_rcu_unlock;
307 	}
308 
309 	err = -EPERM;
310 	if (sock->type == SOCK_RAW && !kern &&
311 	    !ns_capable(net->user_ns, CAP_NET_RAW))
312 		goto out_rcu_unlock;
313 
314 	sock->ops = answer->ops;
315 	answer_prot = answer->prot;
316 	answer_flags = answer->flags;
317 	rcu_read_unlock();
318 
319 	WARN_ON(!answer_prot->slab);
320 
321 	err = -ENOBUFS;
322 	sk = sk_alloc(net, PF_INET, GFP_KERNEL, answer_prot, kern);
323 	if (!sk)
324 		goto out;
325 
326 	err = 0;
327 	if (INET_PROTOSW_REUSE & answer_flags)
328 		sk->sk_reuse = SK_CAN_REUSE;
329 
330 	inet = inet_sk(sk);
331 	inet->is_icsk = (INET_PROTOSW_ICSK & answer_flags) != 0;
332 
333 	inet->nodefrag = 0;
334 
335 	if (SOCK_RAW == sock->type) {
336 		inet->inet_num = protocol;
337 		if (IPPROTO_RAW == protocol)
338 			inet->hdrincl = 1;
339 	}
340 
341 	if (net->ipv4.sysctl_ip_no_pmtu_disc)
342 		inet->pmtudisc = IP_PMTUDISC_DONT;
343 	else
344 		inet->pmtudisc = IP_PMTUDISC_WANT;
345 
346 	inet->inet_id = 0;
347 
348 	sock_init_data(sock, sk);
349 
350 	sk->sk_destruct	   = inet_sock_destruct;
351 	sk->sk_protocol	   = protocol;
352 	sk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;
353 
354 	inet->uc_ttl	= -1;
355 	inet->mc_loop	= 1;
356 	inet->mc_ttl	= 1;
357 	inet->mc_all	= 1;
358 	inet->mc_index	= 0;
359 	inet->mc_list	= NULL;
360 	inet->rcv_tos	= 0;
361 
362 	sk_refcnt_debug_inc(sk);
363 
364 	if (inet->inet_num) {
365 		/* It assumes that any protocol which allows
366 		 * the user to assign a number at socket
367 		 * creation time automatically
368 		 * shares.
369 		 */
370 		inet->inet_sport = htons(inet->inet_num);
371 		/* Add to protocol hash chains. */
372 		err = sk->sk_prot->hash(sk);
373 		if (err) {
374 			sk_common_release(sk);
375 			goto out;
376 		}
377 	}
378 
379 	if (sk->sk_prot->init) {
380 		err = sk->sk_prot->init(sk);
381 		if (err) {
382 			sk_common_release(sk);
383 			goto out;
384 		}
385 	}
386 
387 	if (!kern) {
388 		err = BPF_CGROUP_RUN_PROG_INET_SOCK(sk);
389 		if (err) {
390 			sk_common_release(sk);
391 			goto out;
392 		}
393 	}
394 out:
395 	return err;
396 out_rcu_unlock:
397 	rcu_read_unlock();
398 	goto out;
399 }
400 
401 
402 /*
403  *	The peer socket should always be NULL (or else). When we call this
404  *	function we are destroying the object and from then on nobody
405  *	should refer to it.
406  */
407 int inet_release(struct socket *sock)
408 {
409 	struct sock *sk = sock->sk;
410 
411 	if (sk) {
412 		long timeout;
413 
414 		if (!sk->sk_kern_sock)
415 			BPF_CGROUP_RUN_PROG_INET_SOCK_RELEASE(sk);
416 
417 		/* Applications forget to leave groups before exiting */
418 		ip_mc_drop_socket(sk);
419 
420 		/* If linger is set, we don't return until the close
421 		 * is complete.  Otherwise we return immediately. The
422 		 * actually closing is done the same either way.
423 		 *
424 		 * If the close is due to the process exiting, we never
425 		 * linger..
426 		 */
427 		timeout = 0;
428 		if (sock_flag(sk, SOCK_LINGER) &&
429 		    !(current->flags & PF_EXITING))
430 			timeout = sk->sk_lingertime;
431 		sk->sk_prot->close(sk, timeout);
432 		sock->sk = NULL;
433 	}
434 	return 0;
435 }
436 EXPORT_SYMBOL(inet_release);
437 
438 int inet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
439 {
440 	struct sock *sk = sock->sk;
441 	int err;
442 
443 	/* If the socket has its own bind function then use it. (RAW) */
444 	if (sk->sk_prot->bind) {
445 		return sk->sk_prot->bind(sk, uaddr, addr_len);
446 	}
447 	if (addr_len < sizeof(struct sockaddr_in))
448 		return -EINVAL;
449 
450 	/* BPF prog is run before any checks are done so that if the prog
451 	 * changes context in a wrong way it will be caught.
452 	 */
453 	err = BPF_CGROUP_RUN_PROG_INET4_BIND_LOCK(sk, uaddr);
454 	if (err)
455 		return err;
456 
457 	return __inet_bind(sk, uaddr, addr_len, BIND_WITH_LOCK);
458 }
459 EXPORT_SYMBOL(inet_bind);
460 
461 int __inet_bind(struct sock *sk, struct sockaddr *uaddr, int addr_len,
462 		u32 flags)
463 {
464 	struct sockaddr_in *addr = (struct sockaddr_in *)uaddr;
465 	struct inet_sock *inet = inet_sk(sk);
466 	struct net *net = sock_net(sk);
467 	unsigned short snum;
468 	int chk_addr_ret;
469 	u32 tb_id = RT_TABLE_LOCAL;
470 	int err;
471 
472 	if (addr->sin_family != AF_INET) {
473 		/* Compatibility games : accept AF_UNSPEC (mapped to AF_INET)
474 		 * only if s_addr is INADDR_ANY.
475 		 */
476 		err = -EAFNOSUPPORT;
477 		if (addr->sin_family != AF_UNSPEC ||
478 		    addr->sin_addr.s_addr != htonl(INADDR_ANY))
479 			goto out;
480 	}
481 
482 	tb_id = l3mdev_fib_table_by_index(net, sk->sk_bound_dev_if) ? : tb_id;
483 	chk_addr_ret = inet_addr_type_table(net, addr->sin_addr.s_addr, tb_id);
484 
485 	/* Not specified by any standard per-se, however it breaks too
486 	 * many applications when removed.  It is unfortunate since
487 	 * allowing applications to make a non-local bind solves
488 	 * several problems with systems using dynamic addressing.
489 	 * (ie. your servers still start up even if your ISDN link
490 	 *  is temporarily down)
491 	 */
492 	err = -EADDRNOTAVAIL;
493 	if (!inet_can_nonlocal_bind(net, inet) &&
494 	    addr->sin_addr.s_addr != htonl(INADDR_ANY) &&
495 	    chk_addr_ret != RTN_LOCAL &&
496 	    chk_addr_ret != RTN_MULTICAST &&
497 	    chk_addr_ret != RTN_BROADCAST)
498 		goto out;
499 
500 	snum = ntohs(addr->sin_port);
501 	err = -EACCES;
502 	if (snum && inet_port_requires_bind_service(net, snum) &&
503 	    !ns_capable(net->user_ns, CAP_NET_BIND_SERVICE))
504 		goto out;
505 
506 	/*      We keep a pair of addresses. rcv_saddr is the one
507 	 *      used by hash lookups, and saddr is used for transmit.
508 	 *
509 	 *      In the BSD API these are the same except where it
510 	 *      would be illegal to use them (multicast/broadcast) in
511 	 *      which case the sending device address is used.
512 	 */
513 	if (flags & BIND_WITH_LOCK)
514 		lock_sock(sk);
515 
516 	/* Check these errors (active socket, double bind). */
517 	err = -EINVAL;
518 	if (sk->sk_state != TCP_CLOSE || inet->inet_num)
519 		goto out_release_sock;
520 
521 	inet->inet_rcv_saddr = inet->inet_saddr = addr->sin_addr.s_addr;
522 	if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
523 		inet->inet_saddr = 0;  /* Use device */
524 
525 	/* Make sure we are allowed to bind here. */
526 	if (snum || !(inet->bind_address_no_port ||
527 		      (flags & BIND_FORCE_ADDRESS_NO_PORT))) {
528 		if (sk->sk_prot->get_port(sk, snum)) {
529 			inet->inet_saddr = inet->inet_rcv_saddr = 0;
530 			err = -EADDRINUSE;
531 			goto out_release_sock;
532 		}
533 		if (!(flags & BIND_FROM_BPF)) {
534 			err = BPF_CGROUP_RUN_PROG_INET4_POST_BIND(sk);
535 			if (err) {
536 				inet->inet_saddr = inet->inet_rcv_saddr = 0;
537 				goto out_release_sock;
538 			}
539 		}
540 	}
541 
542 	if (inet->inet_rcv_saddr)
543 		sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
544 	if (snum)
545 		sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
546 	inet->inet_sport = htons(inet->inet_num);
547 	inet->inet_daddr = 0;
548 	inet->inet_dport = 0;
549 	sk_dst_reset(sk);
550 	err = 0;
551 out_release_sock:
552 	if (flags & BIND_WITH_LOCK)
553 		release_sock(sk);
554 out:
555 	return err;
556 }
557 
558 int inet_dgram_connect(struct socket *sock, struct sockaddr *uaddr,
559 		       int addr_len, int flags)
560 {
561 	struct sock *sk = sock->sk;
562 	int err;
563 
564 	if (addr_len < sizeof(uaddr->sa_family))
565 		return -EINVAL;
566 	if (uaddr->sa_family == AF_UNSPEC)
567 		return sk->sk_prot->disconnect(sk, flags);
568 
569 	if (BPF_CGROUP_PRE_CONNECT_ENABLED(sk)) {
570 		err = sk->sk_prot->pre_connect(sk, uaddr, addr_len);
571 		if (err)
572 			return err;
573 	}
574 
575 	if (!inet_sk(sk)->inet_num && inet_autobind(sk))
576 		return -EAGAIN;
577 	return sk->sk_prot->connect(sk, uaddr, addr_len);
578 }
579 EXPORT_SYMBOL(inet_dgram_connect);
580 
581 static long inet_wait_for_connect(struct sock *sk, long timeo, int writebias)
582 {
583 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
584 
585 	add_wait_queue(sk_sleep(sk), &wait);
586 	sk->sk_write_pending += writebias;
587 
588 	/* Basic assumption: if someone sets sk->sk_err, he _must_
589 	 * change state of the socket from TCP_SYN_*.
590 	 * Connect() does not allow to get error notifications
591 	 * without closing the socket.
592 	 */
593 	while ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
594 		release_sock(sk);
595 		timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
596 		lock_sock(sk);
597 		if (signal_pending(current) || !timeo)
598 			break;
599 	}
600 	remove_wait_queue(sk_sleep(sk), &wait);
601 	sk->sk_write_pending -= writebias;
602 	return timeo;
603 }
604 
605 /*
606  *	Connect to a remote host. There is regrettably still a little
607  *	TCP 'magic' in here.
608  */
609 int __inet_stream_connect(struct socket *sock, struct sockaddr *uaddr,
610 			  int addr_len, int flags, int is_sendmsg)
611 {
612 	struct sock *sk = sock->sk;
613 	int err;
614 	long timeo;
615 
616 	/*
617 	 * uaddr can be NULL and addr_len can be 0 if:
618 	 * sk is a TCP fastopen active socket and
619 	 * TCP_FASTOPEN_CONNECT sockopt is set and
620 	 * we already have a valid cookie for this socket.
621 	 * In this case, user can call write() after connect().
622 	 * write() will invoke tcp_sendmsg_fastopen() which calls
623 	 * __inet_stream_connect().
624 	 */
625 	if (uaddr) {
626 		if (addr_len < sizeof(uaddr->sa_family))
627 			return -EINVAL;
628 
629 		if (uaddr->sa_family == AF_UNSPEC) {
630 			err = sk->sk_prot->disconnect(sk, flags);
631 			sock->state = err ? SS_DISCONNECTING : SS_UNCONNECTED;
632 			goto out;
633 		}
634 	}
635 
636 	switch (sock->state) {
637 	default:
638 		err = -EINVAL;
639 		goto out;
640 	case SS_CONNECTED:
641 		err = -EISCONN;
642 		goto out;
643 	case SS_CONNECTING:
644 		if (inet_sk(sk)->defer_connect)
645 			err = is_sendmsg ? -EINPROGRESS : -EISCONN;
646 		else
647 			err = -EALREADY;
648 		/* Fall out of switch with err, set for this state */
649 		break;
650 	case SS_UNCONNECTED:
651 		err = -EISCONN;
652 		if (sk->sk_state != TCP_CLOSE)
653 			goto out;
654 
655 		if (BPF_CGROUP_PRE_CONNECT_ENABLED(sk)) {
656 			err = sk->sk_prot->pre_connect(sk, uaddr, addr_len);
657 			if (err)
658 				goto out;
659 		}
660 
661 		err = sk->sk_prot->connect(sk, uaddr, addr_len);
662 		if (err < 0)
663 			goto out;
664 
665 		sock->state = SS_CONNECTING;
666 
667 		if (!err && inet_sk(sk)->defer_connect)
668 			goto out;
669 
670 		/* Just entered SS_CONNECTING state; the only
671 		 * difference is that return value in non-blocking
672 		 * case is EINPROGRESS, rather than EALREADY.
673 		 */
674 		err = -EINPROGRESS;
675 		break;
676 	}
677 
678 	timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
679 
680 	if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
681 		int writebias = (sk->sk_protocol == IPPROTO_TCP) &&
682 				tcp_sk(sk)->fastopen_req &&
683 				tcp_sk(sk)->fastopen_req->data ? 1 : 0;
684 
685 		/* Error code is set above */
686 		if (!timeo || !inet_wait_for_connect(sk, timeo, writebias))
687 			goto out;
688 
689 		err = sock_intr_errno(timeo);
690 		if (signal_pending(current))
691 			goto out;
692 	}
693 
694 	/* Connection was closed by RST, timeout, ICMP error
695 	 * or another process disconnected us.
696 	 */
697 	if (sk->sk_state == TCP_CLOSE)
698 		goto sock_error;
699 
700 	/* sk->sk_err may be not zero now, if RECVERR was ordered by user
701 	 * and error was received after socket entered established state.
702 	 * Hence, it is handled normally after connect() return successfully.
703 	 */
704 
705 	sock->state = SS_CONNECTED;
706 	err = 0;
707 out:
708 	return err;
709 
710 sock_error:
711 	err = sock_error(sk) ? : -ECONNABORTED;
712 	sock->state = SS_UNCONNECTED;
713 	if (sk->sk_prot->disconnect(sk, flags))
714 		sock->state = SS_DISCONNECTING;
715 	goto out;
716 }
717 EXPORT_SYMBOL(__inet_stream_connect);
718 
719 int inet_stream_connect(struct socket *sock, struct sockaddr *uaddr,
720 			int addr_len, int flags)
721 {
722 	int err;
723 
724 	lock_sock(sock->sk);
725 	err = __inet_stream_connect(sock, uaddr, addr_len, flags, 0);
726 	release_sock(sock->sk);
727 	return err;
728 }
729 EXPORT_SYMBOL(inet_stream_connect);
730 
731 /*
732  *	Accept a pending connection. The TCP layer now gives BSD semantics.
733  */
734 
735 int inet_accept(struct socket *sock, struct socket *newsock, int flags,
736 		bool kern)
737 {
738 	struct sock *sk1 = sock->sk;
739 	int err = -EINVAL;
740 	struct sock *sk2 = sk1->sk_prot->accept(sk1, flags, &err, kern);
741 
742 	if (!sk2)
743 		goto do_err;
744 
745 	lock_sock(sk2);
746 
747 	sock_rps_record_flow(sk2);
748 	WARN_ON(!((1 << sk2->sk_state) &
749 		  (TCPF_ESTABLISHED | TCPF_SYN_RECV |
750 		  TCPF_CLOSE_WAIT | TCPF_CLOSE)));
751 
752 	sock_graft(sk2, newsock);
753 
754 	newsock->state = SS_CONNECTED;
755 	err = 0;
756 	release_sock(sk2);
757 do_err:
758 	return err;
759 }
760 EXPORT_SYMBOL(inet_accept);
761 
762 /*
763  *	This does both peername and sockname.
764  */
765 int inet_getname(struct socket *sock, struct sockaddr *uaddr,
766 		 int peer)
767 {
768 	struct sock *sk		= sock->sk;
769 	struct inet_sock *inet	= inet_sk(sk);
770 	DECLARE_SOCKADDR(struct sockaddr_in *, sin, uaddr);
771 
772 	sin->sin_family = AF_INET;
773 	if (peer) {
774 		if (!inet->inet_dport ||
775 		    (((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_SYN_SENT)) &&
776 		     peer == 1))
777 			return -ENOTCONN;
778 		sin->sin_port = inet->inet_dport;
779 		sin->sin_addr.s_addr = inet->inet_daddr;
780 	} else {
781 		__be32 addr = inet->inet_rcv_saddr;
782 		if (!addr)
783 			addr = inet->inet_saddr;
784 		sin->sin_port = inet->inet_sport;
785 		sin->sin_addr.s_addr = addr;
786 	}
787 	if (cgroup_bpf_enabled)
788 		BPF_CGROUP_RUN_SA_PROG_LOCK(sk, (struct sockaddr *)sin,
789 					    peer ? BPF_CGROUP_INET4_GETPEERNAME :
790 						   BPF_CGROUP_INET4_GETSOCKNAME,
791 					    NULL);
792 	memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
793 	return sizeof(*sin);
794 }
795 EXPORT_SYMBOL(inet_getname);
796 
797 int inet_send_prepare(struct sock *sk)
798 {
799 	sock_rps_record_flow(sk);
800 
801 	/* We may need to bind the socket. */
802 	if (!inet_sk(sk)->inet_num && !sk->sk_prot->no_autobind &&
803 	    inet_autobind(sk))
804 		return -EAGAIN;
805 
806 	return 0;
807 }
808 EXPORT_SYMBOL_GPL(inet_send_prepare);
809 
810 int inet_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
811 {
812 	struct sock *sk = sock->sk;
813 
814 	if (unlikely(inet_send_prepare(sk)))
815 		return -EAGAIN;
816 
817 	return INDIRECT_CALL_2(sk->sk_prot->sendmsg, tcp_sendmsg, udp_sendmsg,
818 			       sk, msg, size);
819 }
820 EXPORT_SYMBOL(inet_sendmsg);
821 
822 ssize_t inet_sendpage(struct socket *sock, struct page *page, int offset,
823 		      size_t size, int flags)
824 {
825 	struct sock *sk = sock->sk;
826 
827 	if (unlikely(inet_send_prepare(sk)))
828 		return -EAGAIN;
829 
830 	if (sk->sk_prot->sendpage)
831 		return sk->sk_prot->sendpage(sk, page, offset, size, flags);
832 	return sock_no_sendpage(sock, page, offset, size, flags);
833 }
834 EXPORT_SYMBOL(inet_sendpage);
835 
836 INDIRECT_CALLABLE_DECLARE(int udp_recvmsg(struct sock *, struct msghdr *,
837 					  size_t, int, int, int *));
838 int inet_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
839 		 int flags)
840 {
841 	struct sock *sk = sock->sk;
842 	int addr_len = 0;
843 	int err;
844 
845 	if (likely(!(flags & MSG_ERRQUEUE)))
846 		sock_rps_record_flow(sk);
847 
848 	err = INDIRECT_CALL_2(sk->sk_prot->recvmsg, tcp_recvmsg, udp_recvmsg,
849 			      sk, msg, size, flags & MSG_DONTWAIT,
850 			      flags & ~MSG_DONTWAIT, &addr_len);
851 	if (err >= 0)
852 		msg->msg_namelen = addr_len;
853 	return err;
854 }
855 EXPORT_SYMBOL(inet_recvmsg);
856 
857 int inet_shutdown(struct socket *sock, int how)
858 {
859 	struct sock *sk = sock->sk;
860 	int err = 0;
861 
862 	/* This should really check to make sure
863 	 * the socket is a TCP socket. (WHY AC...)
864 	 */
865 	how++; /* maps 0->1 has the advantage of making bit 1 rcvs and
866 		       1->2 bit 2 snds.
867 		       2->3 */
868 	if ((how & ~SHUTDOWN_MASK) || !how)	/* MAXINT->0 */
869 		return -EINVAL;
870 
871 	lock_sock(sk);
872 	if (sock->state == SS_CONNECTING) {
873 		if ((1 << sk->sk_state) &
874 		    (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE))
875 			sock->state = SS_DISCONNECTING;
876 		else
877 			sock->state = SS_CONNECTED;
878 	}
879 
880 	switch (sk->sk_state) {
881 	case TCP_CLOSE:
882 		err = -ENOTCONN;
883 		/* Hack to wake up other listeners, who can poll for
884 		   EPOLLHUP, even on eg. unconnected UDP sockets -- RR */
885 		fallthrough;
886 	default:
887 		sk->sk_shutdown |= how;
888 		if (sk->sk_prot->shutdown)
889 			sk->sk_prot->shutdown(sk, how);
890 		break;
891 
892 	/* Remaining two branches are temporary solution for missing
893 	 * close() in multithreaded environment. It is _not_ a good idea,
894 	 * but we have no choice until close() is repaired at VFS level.
895 	 */
896 	case TCP_LISTEN:
897 		if (!(how & RCV_SHUTDOWN))
898 			break;
899 		fallthrough;
900 	case TCP_SYN_SENT:
901 		err = sk->sk_prot->disconnect(sk, O_NONBLOCK);
902 		sock->state = err ? SS_DISCONNECTING : SS_UNCONNECTED;
903 		break;
904 	}
905 
906 	/* Wake up anyone sleeping in poll. */
907 	sk->sk_state_change(sk);
908 	release_sock(sk);
909 	return err;
910 }
911 EXPORT_SYMBOL(inet_shutdown);
912 
913 /*
914  *	ioctl() calls you can issue on an INET socket. Most of these are
915  *	device configuration and stuff and very rarely used. Some ioctls
916  *	pass on to the socket itself.
917  *
918  *	NOTE: I like the idea of a module for the config stuff. ie ifconfig
919  *	loads the devconfigure module does its configuring and unloads it.
920  *	There's a good 20K of config code hanging around the kernel.
921  */
922 
923 int inet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
924 {
925 	struct sock *sk = sock->sk;
926 	int err = 0;
927 	struct net *net = sock_net(sk);
928 	void __user *p = (void __user *)arg;
929 	struct ifreq ifr;
930 	struct rtentry rt;
931 
932 	switch (cmd) {
933 	case SIOCADDRT:
934 	case SIOCDELRT:
935 		if (copy_from_user(&rt, p, sizeof(struct rtentry)))
936 			return -EFAULT;
937 		err = ip_rt_ioctl(net, cmd, &rt);
938 		break;
939 	case SIOCRTMSG:
940 		err = -EINVAL;
941 		break;
942 	case SIOCDARP:
943 	case SIOCGARP:
944 	case SIOCSARP:
945 		err = arp_ioctl(net, cmd, (void __user *)arg);
946 		break;
947 	case SIOCGIFADDR:
948 	case SIOCGIFBRDADDR:
949 	case SIOCGIFNETMASK:
950 	case SIOCGIFDSTADDR:
951 	case SIOCGIFPFLAGS:
952 		if (copy_from_user(&ifr, p, sizeof(struct ifreq)))
953 			return -EFAULT;
954 		err = devinet_ioctl(net, cmd, &ifr);
955 		if (!err && copy_to_user(p, &ifr, sizeof(struct ifreq)))
956 			err = -EFAULT;
957 		break;
958 
959 	case SIOCSIFADDR:
960 	case SIOCSIFBRDADDR:
961 	case SIOCSIFNETMASK:
962 	case SIOCSIFDSTADDR:
963 	case SIOCSIFPFLAGS:
964 	case SIOCSIFFLAGS:
965 		if (copy_from_user(&ifr, p, sizeof(struct ifreq)))
966 			return -EFAULT;
967 		err = devinet_ioctl(net, cmd, &ifr);
968 		break;
969 	default:
970 		if (sk->sk_prot->ioctl)
971 			err = sk->sk_prot->ioctl(sk, cmd, arg);
972 		else
973 			err = -ENOIOCTLCMD;
974 		break;
975 	}
976 	return err;
977 }
978 EXPORT_SYMBOL(inet_ioctl);
979 
980 #ifdef CONFIG_COMPAT
981 static int inet_compat_routing_ioctl(struct sock *sk, unsigned int cmd,
982 		struct compat_rtentry __user *ur)
983 {
984 	compat_uptr_t rtdev;
985 	struct rtentry rt;
986 
987 	if (copy_from_user(&rt.rt_dst, &ur->rt_dst,
988 			3 * sizeof(struct sockaddr)) ||
989 	    get_user(rt.rt_flags, &ur->rt_flags) ||
990 	    get_user(rt.rt_metric, &ur->rt_metric) ||
991 	    get_user(rt.rt_mtu, &ur->rt_mtu) ||
992 	    get_user(rt.rt_window, &ur->rt_window) ||
993 	    get_user(rt.rt_irtt, &ur->rt_irtt) ||
994 	    get_user(rtdev, &ur->rt_dev))
995 		return -EFAULT;
996 
997 	rt.rt_dev = compat_ptr(rtdev);
998 	return ip_rt_ioctl(sock_net(sk), cmd, &rt);
999 }
1000 
1001 static int inet_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
1002 {
1003 	void __user *argp = compat_ptr(arg);
1004 	struct sock *sk = sock->sk;
1005 
1006 	switch (cmd) {
1007 	case SIOCADDRT:
1008 	case SIOCDELRT:
1009 		return inet_compat_routing_ioctl(sk, cmd, argp);
1010 	default:
1011 		if (!sk->sk_prot->compat_ioctl)
1012 			return -ENOIOCTLCMD;
1013 		return sk->sk_prot->compat_ioctl(sk, cmd, arg);
1014 	}
1015 }
1016 #endif /* CONFIG_COMPAT */
1017 
1018 const struct proto_ops inet_stream_ops = {
1019 	.family		   = PF_INET,
1020 	.flags		   = PROTO_CMSG_DATA_ONLY,
1021 	.owner		   = THIS_MODULE,
1022 	.release	   = inet_release,
1023 	.bind		   = inet_bind,
1024 	.connect	   = inet_stream_connect,
1025 	.socketpair	   = sock_no_socketpair,
1026 	.accept		   = inet_accept,
1027 	.getname	   = inet_getname,
1028 	.poll		   = tcp_poll,
1029 	.ioctl		   = inet_ioctl,
1030 	.gettstamp	   = sock_gettstamp,
1031 	.listen		   = inet_listen,
1032 	.shutdown	   = inet_shutdown,
1033 	.setsockopt	   = sock_common_setsockopt,
1034 	.getsockopt	   = sock_common_getsockopt,
1035 	.sendmsg	   = inet_sendmsg,
1036 	.recvmsg	   = inet_recvmsg,
1037 #ifdef CONFIG_MMU
1038 	.mmap		   = tcp_mmap,
1039 #endif
1040 	.sendpage	   = inet_sendpage,
1041 	.splice_read	   = tcp_splice_read,
1042 	.read_sock	   = tcp_read_sock,
1043 	.sendmsg_locked    = tcp_sendmsg_locked,
1044 	.sendpage_locked   = tcp_sendpage_locked,
1045 	.peek_len	   = tcp_peek_len,
1046 #ifdef CONFIG_COMPAT
1047 	.compat_ioctl	   = inet_compat_ioctl,
1048 #endif
1049 	.set_rcvlowat	   = tcp_set_rcvlowat,
1050 };
1051 EXPORT_SYMBOL(inet_stream_ops);
1052 
1053 const struct proto_ops inet_dgram_ops = {
1054 	.family		   = PF_INET,
1055 	.owner		   = THIS_MODULE,
1056 	.release	   = inet_release,
1057 	.bind		   = inet_bind,
1058 	.connect	   = inet_dgram_connect,
1059 	.socketpair	   = sock_no_socketpair,
1060 	.accept		   = sock_no_accept,
1061 	.getname	   = inet_getname,
1062 	.poll		   = udp_poll,
1063 	.ioctl		   = inet_ioctl,
1064 	.gettstamp	   = sock_gettstamp,
1065 	.listen		   = sock_no_listen,
1066 	.shutdown	   = inet_shutdown,
1067 	.setsockopt	   = sock_common_setsockopt,
1068 	.getsockopt	   = sock_common_getsockopt,
1069 	.sendmsg	   = inet_sendmsg,
1070 	.recvmsg	   = inet_recvmsg,
1071 	.mmap		   = sock_no_mmap,
1072 	.sendpage	   = inet_sendpage,
1073 	.set_peek_off	   = sk_set_peek_off,
1074 #ifdef CONFIG_COMPAT
1075 	.compat_ioctl	   = inet_compat_ioctl,
1076 #endif
1077 };
1078 EXPORT_SYMBOL(inet_dgram_ops);
1079 
1080 /*
1081  * For SOCK_RAW sockets; should be the same as inet_dgram_ops but without
1082  * udp_poll
1083  */
1084 static const struct proto_ops inet_sockraw_ops = {
1085 	.family		   = PF_INET,
1086 	.owner		   = THIS_MODULE,
1087 	.release	   = inet_release,
1088 	.bind		   = inet_bind,
1089 	.connect	   = inet_dgram_connect,
1090 	.socketpair	   = sock_no_socketpair,
1091 	.accept		   = sock_no_accept,
1092 	.getname	   = inet_getname,
1093 	.poll		   = datagram_poll,
1094 	.ioctl		   = inet_ioctl,
1095 	.gettstamp	   = sock_gettstamp,
1096 	.listen		   = sock_no_listen,
1097 	.shutdown	   = inet_shutdown,
1098 	.setsockopt	   = sock_common_setsockopt,
1099 	.getsockopt	   = sock_common_getsockopt,
1100 	.sendmsg	   = inet_sendmsg,
1101 	.recvmsg	   = inet_recvmsg,
1102 	.mmap		   = sock_no_mmap,
1103 	.sendpage	   = inet_sendpage,
1104 #ifdef CONFIG_COMPAT
1105 	.compat_ioctl	   = inet_compat_ioctl,
1106 #endif
1107 };
1108 
1109 static const struct net_proto_family inet_family_ops = {
1110 	.family = PF_INET,
1111 	.create = inet_create,
1112 	.owner	= THIS_MODULE,
1113 };
1114 
1115 /* Upon startup we insert all the elements in inetsw_array[] into
1116  * the linked list inetsw.
1117  */
1118 static struct inet_protosw inetsw_array[] =
1119 {
1120 	{
1121 		.type =       SOCK_STREAM,
1122 		.protocol =   IPPROTO_TCP,
1123 		.prot =       &tcp_prot,
1124 		.ops =        &inet_stream_ops,
1125 		.flags =      INET_PROTOSW_PERMANENT |
1126 			      INET_PROTOSW_ICSK,
1127 	},
1128 
1129 	{
1130 		.type =       SOCK_DGRAM,
1131 		.protocol =   IPPROTO_UDP,
1132 		.prot =       &udp_prot,
1133 		.ops =        &inet_dgram_ops,
1134 		.flags =      INET_PROTOSW_PERMANENT,
1135        },
1136 
1137        {
1138 		.type =       SOCK_DGRAM,
1139 		.protocol =   IPPROTO_ICMP,
1140 		.prot =       &ping_prot,
1141 		.ops =        &inet_sockraw_ops,
1142 		.flags =      INET_PROTOSW_REUSE,
1143        },
1144 
1145        {
1146 	       .type =       SOCK_RAW,
1147 	       .protocol =   IPPROTO_IP,	/* wild card */
1148 	       .prot =       &raw_prot,
1149 	       .ops =        &inet_sockraw_ops,
1150 	       .flags =      INET_PROTOSW_REUSE,
1151        }
1152 };
1153 
1154 #define INETSW_ARRAY_LEN ARRAY_SIZE(inetsw_array)
1155 
1156 void inet_register_protosw(struct inet_protosw *p)
1157 {
1158 	struct list_head *lh;
1159 	struct inet_protosw *answer;
1160 	int protocol = p->protocol;
1161 	struct list_head *last_perm;
1162 
1163 	spin_lock_bh(&inetsw_lock);
1164 
1165 	if (p->type >= SOCK_MAX)
1166 		goto out_illegal;
1167 
1168 	/* If we are trying to override a permanent protocol, bail. */
1169 	last_perm = &inetsw[p->type];
1170 	list_for_each(lh, &inetsw[p->type]) {
1171 		answer = list_entry(lh, struct inet_protosw, list);
1172 		/* Check only the non-wild match. */
1173 		if ((INET_PROTOSW_PERMANENT & answer->flags) == 0)
1174 			break;
1175 		if (protocol == answer->protocol)
1176 			goto out_permanent;
1177 		last_perm = lh;
1178 	}
1179 
1180 	/* Add the new entry after the last permanent entry if any, so that
1181 	 * the new entry does not override a permanent entry when matched with
1182 	 * a wild-card protocol. But it is allowed to override any existing
1183 	 * non-permanent entry.  This means that when we remove this entry, the
1184 	 * system automatically returns to the old behavior.
1185 	 */
1186 	list_add_rcu(&p->list, last_perm);
1187 out:
1188 	spin_unlock_bh(&inetsw_lock);
1189 
1190 	return;
1191 
1192 out_permanent:
1193 	pr_err("Attempt to override permanent protocol %d\n", protocol);
1194 	goto out;
1195 
1196 out_illegal:
1197 	pr_err("Ignoring attempt to register invalid socket type %d\n",
1198 	       p->type);
1199 	goto out;
1200 }
1201 EXPORT_SYMBOL(inet_register_protosw);
1202 
1203 void inet_unregister_protosw(struct inet_protosw *p)
1204 {
1205 	if (INET_PROTOSW_PERMANENT & p->flags) {
1206 		pr_err("Attempt to unregister permanent protocol %d\n",
1207 		       p->protocol);
1208 	} else {
1209 		spin_lock_bh(&inetsw_lock);
1210 		list_del_rcu(&p->list);
1211 		spin_unlock_bh(&inetsw_lock);
1212 
1213 		synchronize_net();
1214 	}
1215 }
1216 EXPORT_SYMBOL(inet_unregister_protosw);
1217 
1218 static int inet_sk_reselect_saddr(struct sock *sk)
1219 {
1220 	struct inet_sock *inet = inet_sk(sk);
1221 	__be32 old_saddr = inet->inet_saddr;
1222 	__be32 daddr = inet->inet_daddr;
1223 	struct flowi4 *fl4;
1224 	struct rtable *rt;
1225 	__be32 new_saddr;
1226 	struct ip_options_rcu *inet_opt;
1227 
1228 	inet_opt = rcu_dereference_protected(inet->inet_opt,
1229 					     lockdep_sock_is_held(sk));
1230 	if (inet_opt && inet_opt->opt.srr)
1231 		daddr = inet_opt->opt.faddr;
1232 
1233 	/* Query new route. */
1234 	fl4 = &inet->cork.fl.u.ip4;
1235 	rt = ip_route_connect(fl4, daddr, 0, RT_CONN_FLAGS(sk),
1236 			      sk->sk_bound_dev_if, sk->sk_protocol,
1237 			      inet->inet_sport, inet->inet_dport, sk);
1238 	if (IS_ERR(rt))
1239 		return PTR_ERR(rt);
1240 
1241 	sk_setup_caps(sk, &rt->dst);
1242 
1243 	new_saddr = fl4->saddr;
1244 
1245 	if (new_saddr == old_saddr)
1246 		return 0;
1247 
1248 	if (sock_net(sk)->ipv4.sysctl_ip_dynaddr > 1) {
1249 		pr_info("%s(): shifting inet->saddr from %pI4 to %pI4\n",
1250 			__func__, &old_saddr, &new_saddr);
1251 	}
1252 
1253 	inet->inet_saddr = inet->inet_rcv_saddr = new_saddr;
1254 
1255 	/*
1256 	 * XXX The only one ugly spot where we need to
1257 	 * XXX really change the sockets identity after
1258 	 * XXX it has entered the hashes. -DaveM
1259 	 *
1260 	 * Besides that, it does not check for connection
1261 	 * uniqueness. Wait for troubles.
1262 	 */
1263 	return __sk_prot_rehash(sk);
1264 }
1265 
1266 int inet_sk_rebuild_header(struct sock *sk)
1267 {
1268 	struct inet_sock *inet = inet_sk(sk);
1269 	struct rtable *rt = (struct rtable *)__sk_dst_check(sk, 0);
1270 	__be32 daddr;
1271 	struct ip_options_rcu *inet_opt;
1272 	struct flowi4 *fl4;
1273 	int err;
1274 
1275 	/* Route is OK, nothing to do. */
1276 	if (rt)
1277 		return 0;
1278 
1279 	/* Reroute. */
1280 	rcu_read_lock();
1281 	inet_opt = rcu_dereference(inet->inet_opt);
1282 	daddr = inet->inet_daddr;
1283 	if (inet_opt && inet_opt->opt.srr)
1284 		daddr = inet_opt->opt.faddr;
1285 	rcu_read_unlock();
1286 	fl4 = &inet->cork.fl.u.ip4;
1287 	rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr, inet->inet_saddr,
1288 				   inet->inet_dport, inet->inet_sport,
1289 				   sk->sk_protocol, RT_CONN_FLAGS(sk),
1290 				   sk->sk_bound_dev_if);
1291 	if (!IS_ERR(rt)) {
1292 		err = 0;
1293 		sk_setup_caps(sk, &rt->dst);
1294 	} else {
1295 		err = PTR_ERR(rt);
1296 
1297 		/* Routing failed... */
1298 		sk->sk_route_caps = 0;
1299 		/*
1300 		 * Other protocols have to map its equivalent state to TCP_SYN_SENT.
1301 		 * DCCP maps its DCCP_REQUESTING state to TCP_SYN_SENT. -acme
1302 		 */
1303 		if (!sock_net(sk)->ipv4.sysctl_ip_dynaddr ||
1304 		    sk->sk_state != TCP_SYN_SENT ||
1305 		    (sk->sk_userlocks & SOCK_BINDADDR_LOCK) ||
1306 		    (err = inet_sk_reselect_saddr(sk)) != 0)
1307 			sk->sk_err_soft = -err;
1308 	}
1309 
1310 	return err;
1311 }
1312 EXPORT_SYMBOL(inet_sk_rebuild_header);
1313 
1314 void inet_sk_set_state(struct sock *sk, int state)
1315 {
1316 	trace_inet_sock_set_state(sk, sk->sk_state, state);
1317 	sk->sk_state = state;
1318 }
1319 EXPORT_SYMBOL(inet_sk_set_state);
1320 
1321 void inet_sk_state_store(struct sock *sk, int newstate)
1322 {
1323 	trace_inet_sock_set_state(sk, sk->sk_state, newstate);
1324 	smp_store_release(&sk->sk_state, newstate);
1325 }
1326 
1327 struct sk_buff *inet_gso_segment(struct sk_buff *skb,
1328 				 netdev_features_t features)
1329 {
1330 	bool udpfrag = false, fixedid = false, gso_partial, encap;
1331 	struct sk_buff *segs = ERR_PTR(-EINVAL);
1332 	const struct net_offload *ops;
1333 	unsigned int offset = 0;
1334 	struct iphdr *iph;
1335 	int proto, tot_len;
1336 	int nhoff;
1337 	int ihl;
1338 	int id;
1339 
1340 	skb_reset_network_header(skb);
1341 	nhoff = skb_network_header(skb) - skb_mac_header(skb);
1342 	if (unlikely(!pskb_may_pull(skb, sizeof(*iph))))
1343 		goto out;
1344 
1345 	iph = ip_hdr(skb);
1346 	ihl = iph->ihl * 4;
1347 	if (ihl < sizeof(*iph))
1348 		goto out;
1349 
1350 	id = ntohs(iph->id);
1351 	proto = iph->protocol;
1352 
1353 	/* Warning: after this point, iph might be no longer valid */
1354 	if (unlikely(!pskb_may_pull(skb, ihl)))
1355 		goto out;
1356 	__skb_pull(skb, ihl);
1357 
1358 	encap = SKB_GSO_CB(skb)->encap_level > 0;
1359 	if (encap)
1360 		features &= skb->dev->hw_enc_features;
1361 	SKB_GSO_CB(skb)->encap_level += ihl;
1362 
1363 	skb_reset_transport_header(skb);
1364 
1365 	segs = ERR_PTR(-EPROTONOSUPPORT);
1366 
1367 	if (!skb->encapsulation || encap) {
1368 		udpfrag = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
1369 		fixedid = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TCP_FIXEDID);
1370 
1371 		/* fixed ID is invalid if DF bit is not set */
1372 		if (fixedid && !(ip_hdr(skb)->frag_off & htons(IP_DF)))
1373 			goto out;
1374 	}
1375 
1376 	ops = rcu_dereference(inet_offloads[proto]);
1377 	if (likely(ops && ops->callbacks.gso_segment))
1378 		segs = ops->callbacks.gso_segment(skb, features);
1379 
1380 	if (IS_ERR_OR_NULL(segs))
1381 		goto out;
1382 
1383 	gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
1384 
1385 	skb = segs;
1386 	do {
1387 		iph = (struct iphdr *)(skb_mac_header(skb) + nhoff);
1388 		if (udpfrag) {
1389 			iph->frag_off = htons(offset >> 3);
1390 			if (skb->next)
1391 				iph->frag_off |= htons(IP_MF);
1392 			offset += skb->len - nhoff - ihl;
1393 			tot_len = skb->len - nhoff;
1394 		} else if (skb_is_gso(skb)) {
1395 			if (!fixedid) {
1396 				iph->id = htons(id);
1397 				id += skb_shinfo(skb)->gso_segs;
1398 			}
1399 
1400 			if (gso_partial)
1401 				tot_len = skb_shinfo(skb)->gso_size +
1402 					  SKB_GSO_CB(skb)->data_offset +
1403 					  skb->head - (unsigned char *)iph;
1404 			else
1405 				tot_len = skb->len - nhoff;
1406 		} else {
1407 			if (!fixedid)
1408 				iph->id = htons(id++);
1409 			tot_len = skb->len - nhoff;
1410 		}
1411 		iph->tot_len = htons(tot_len);
1412 		ip_send_check(iph);
1413 		if (encap)
1414 			skb_reset_inner_headers(skb);
1415 		skb->network_header = (u8 *)iph - skb->head;
1416 		skb_reset_mac_len(skb);
1417 	} while ((skb = skb->next));
1418 
1419 out:
1420 	return segs;
1421 }
1422 EXPORT_SYMBOL(inet_gso_segment);
1423 
1424 static struct sk_buff *ipip_gso_segment(struct sk_buff *skb,
1425 					netdev_features_t features)
1426 {
1427 	if (!(skb_shinfo(skb)->gso_type & SKB_GSO_IPXIP4))
1428 		return ERR_PTR(-EINVAL);
1429 
1430 	return inet_gso_segment(skb, features);
1431 }
1432 
1433 struct sk_buff *inet_gro_receive(struct list_head *head, struct sk_buff *skb)
1434 {
1435 	const struct net_offload *ops;
1436 	struct sk_buff *pp = NULL;
1437 	const struct iphdr *iph;
1438 	struct sk_buff *p;
1439 	unsigned int hlen;
1440 	unsigned int off;
1441 	unsigned int id;
1442 	int flush = 1;
1443 	int proto;
1444 
1445 	off = skb_gro_offset(skb);
1446 	hlen = off + sizeof(*iph);
1447 	iph = skb_gro_header_fast(skb, off);
1448 	if (skb_gro_header_hard(skb, hlen)) {
1449 		iph = skb_gro_header_slow(skb, hlen, off);
1450 		if (unlikely(!iph))
1451 			goto out;
1452 	}
1453 
1454 	proto = iph->protocol;
1455 
1456 	rcu_read_lock();
1457 	ops = rcu_dereference(inet_offloads[proto]);
1458 	if (!ops || !ops->callbacks.gro_receive)
1459 		goto out_unlock;
1460 
1461 	if (*(u8 *)iph != 0x45)
1462 		goto out_unlock;
1463 
1464 	if (ip_is_fragment(iph))
1465 		goto out_unlock;
1466 
1467 	if (unlikely(ip_fast_csum((u8 *)iph, 5)))
1468 		goto out_unlock;
1469 
1470 	id = ntohl(*(__be32 *)&iph->id);
1471 	flush = (u16)((ntohl(*(__be32 *)iph) ^ skb_gro_len(skb)) | (id & ~IP_DF));
1472 	id >>= 16;
1473 
1474 	list_for_each_entry(p, head, list) {
1475 		struct iphdr *iph2;
1476 		u16 flush_id;
1477 
1478 		if (!NAPI_GRO_CB(p)->same_flow)
1479 			continue;
1480 
1481 		iph2 = (struct iphdr *)(p->data + off);
1482 		/* The above works because, with the exception of the top
1483 		 * (inner most) layer, we only aggregate pkts with the same
1484 		 * hdr length so all the hdrs we'll need to verify will start
1485 		 * at the same offset.
1486 		 */
1487 		if ((iph->protocol ^ iph2->protocol) |
1488 		    ((__force u32)iph->saddr ^ (__force u32)iph2->saddr) |
1489 		    ((__force u32)iph->daddr ^ (__force u32)iph2->daddr)) {
1490 			NAPI_GRO_CB(p)->same_flow = 0;
1491 			continue;
1492 		}
1493 
1494 		/* All fields must match except length and checksum. */
1495 		NAPI_GRO_CB(p)->flush |=
1496 			(iph->ttl ^ iph2->ttl) |
1497 			(iph->tos ^ iph2->tos) |
1498 			((iph->frag_off ^ iph2->frag_off) & htons(IP_DF));
1499 
1500 		NAPI_GRO_CB(p)->flush |= flush;
1501 
1502 		/* We need to store of the IP ID check to be included later
1503 		 * when we can verify that this packet does in fact belong
1504 		 * to a given flow.
1505 		 */
1506 		flush_id = (u16)(id - ntohs(iph2->id));
1507 
1508 		/* This bit of code makes it much easier for us to identify
1509 		 * the cases where we are doing atomic vs non-atomic IP ID
1510 		 * checks.  Specifically an atomic check can return IP ID
1511 		 * values 0 - 0xFFFF, while a non-atomic check can only
1512 		 * return 0 or 0xFFFF.
1513 		 */
1514 		if (!NAPI_GRO_CB(p)->is_atomic ||
1515 		    !(iph->frag_off & htons(IP_DF))) {
1516 			flush_id ^= NAPI_GRO_CB(p)->count;
1517 			flush_id = flush_id ? 0xFFFF : 0;
1518 		}
1519 
1520 		/* If the previous IP ID value was based on an atomic
1521 		 * datagram we can overwrite the value and ignore it.
1522 		 */
1523 		if (NAPI_GRO_CB(skb)->is_atomic)
1524 			NAPI_GRO_CB(p)->flush_id = flush_id;
1525 		else
1526 			NAPI_GRO_CB(p)->flush_id |= flush_id;
1527 	}
1528 
1529 	NAPI_GRO_CB(skb)->is_atomic = !!(iph->frag_off & htons(IP_DF));
1530 	NAPI_GRO_CB(skb)->flush |= flush;
1531 	skb_set_network_header(skb, off);
1532 	/* The above will be needed by the transport layer if there is one
1533 	 * immediately following this IP hdr.
1534 	 */
1535 
1536 	/* Note : No need to call skb_gro_postpull_rcsum() here,
1537 	 * as we already checked checksum over ipv4 header was 0
1538 	 */
1539 	skb_gro_pull(skb, sizeof(*iph));
1540 	skb_set_transport_header(skb, skb_gro_offset(skb));
1541 
1542 	pp = indirect_call_gro_receive(tcp4_gro_receive, udp4_gro_receive,
1543 				       ops->callbacks.gro_receive, head, skb);
1544 
1545 out_unlock:
1546 	rcu_read_unlock();
1547 
1548 out:
1549 	skb_gro_flush_final(skb, pp, flush);
1550 
1551 	return pp;
1552 }
1553 EXPORT_SYMBOL(inet_gro_receive);
1554 
1555 static struct sk_buff *ipip_gro_receive(struct list_head *head,
1556 					struct sk_buff *skb)
1557 {
1558 	if (NAPI_GRO_CB(skb)->encap_mark) {
1559 		NAPI_GRO_CB(skb)->flush = 1;
1560 		return NULL;
1561 	}
1562 
1563 	NAPI_GRO_CB(skb)->encap_mark = 1;
1564 
1565 	return inet_gro_receive(head, skb);
1566 }
1567 
1568 #define SECONDS_PER_DAY	86400
1569 
1570 /* inet_current_timestamp - Return IP network timestamp
1571  *
1572  * Return milliseconds since midnight in network byte order.
1573  */
1574 __be32 inet_current_timestamp(void)
1575 {
1576 	u32 secs;
1577 	u32 msecs;
1578 	struct timespec64 ts;
1579 
1580 	ktime_get_real_ts64(&ts);
1581 
1582 	/* Get secs since midnight. */
1583 	(void)div_u64_rem(ts.tv_sec, SECONDS_PER_DAY, &secs);
1584 	/* Convert to msecs. */
1585 	msecs = secs * MSEC_PER_SEC;
1586 	/* Convert nsec to msec. */
1587 	msecs += (u32)ts.tv_nsec / NSEC_PER_MSEC;
1588 
1589 	/* Convert to network byte order. */
1590 	return htonl(msecs);
1591 }
1592 EXPORT_SYMBOL(inet_current_timestamp);
1593 
1594 int inet_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
1595 {
1596 	if (sk->sk_family == AF_INET)
1597 		return ip_recv_error(sk, msg, len, addr_len);
1598 #if IS_ENABLED(CONFIG_IPV6)
1599 	if (sk->sk_family == AF_INET6)
1600 		return pingv6_ops.ipv6_recv_error(sk, msg, len, addr_len);
1601 #endif
1602 	return -EINVAL;
1603 }
1604 
1605 int inet_gro_complete(struct sk_buff *skb, int nhoff)
1606 {
1607 	__be16 newlen = htons(skb->len - nhoff);
1608 	struct iphdr *iph = (struct iphdr *)(skb->data + nhoff);
1609 	const struct net_offload *ops;
1610 	int proto = iph->protocol;
1611 	int err = -ENOSYS;
1612 
1613 	if (skb->encapsulation) {
1614 		skb_set_inner_protocol(skb, cpu_to_be16(ETH_P_IP));
1615 		skb_set_inner_network_header(skb, nhoff);
1616 	}
1617 
1618 	csum_replace2(&iph->check, iph->tot_len, newlen);
1619 	iph->tot_len = newlen;
1620 
1621 	rcu_read_lock();
1622 	ops = rcu_dereference(inet_offloads[proto]);
1623 	if (WARN_ON(!ops || !ops->callbacks.gro_complete))
1624 		goto out_unlock;
1625 
1626 	/* Only need to add sizeof(*iph) to get to the next hdr below
1627 	 * because any hdr with option will have been flushed in
1628 	 * inet_gro_receive().
1629 	 */
1630 	err = INDIRECT_CALL_2(ops->callbacks.gro_complete,
1631 			      tcp4_gro_complete, udp4_gro_complete,
1632 			      skb, nhoff + sizeof(*iph));
1633 
1634 out_unlock:
1635 	rcu_read_unlock();
1636 
1637 	return err;
1638 }
1639 EXPORT_SYMBOL(inet_gro_complete);
1640 
1641 static int ipip_gro_complete(struct sk_buff *skb, int nhoff)
1642 {
1643 	skb->encapsulation = 1;
1644 	skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
1645 	return inet_gro_complete(skb, nhoff);
1646 }
1647 
1648 int inet_ctl_sock_create(struct sock **sk, unsigned short family,
1649 			 unsigned short type, unsigned char protocol,
1650 			 struct net *net)
1651 {
1652 	struct socket *sock;
1653 	int rc = sock_create_kern(net, family, type, protocol, &sock);
1654 
1655 	if (rc == 0) {
1656 		*sk = sock->sk;
1657 		(*sk)->sk_allocation = GFP_ATOMIC;
1658 		/*
1659 		 * Unhash it so that IP input processing does not even see it,
1660 		 * we do not wish this socket to see incoming packets.
1661 		 */
1662 		(*sk)->sk_prot->unhash(*sk);
1663 	}
1664 	return rc;
1665 }
1666 EXPORT_SYMBOL_GPL(inet_ctl_sock_create);
1667 
1668 u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offt)
1669 {
1670 	return  *(((unsigned long *)per_cpu_ptr(mib, cpu)) + offt);
1671 }
1672 EXPORT_SYMBOL_GPL(snmp_get_cpu_field);
1673 
1674 unsigned long snmp_fold_field(void __percpu *mib, int offt)
1675 {
1676 	unsigned long res = 0;
1677 	int i;
1678 
1679 	for_each_possible_cpu(i)
1680 		res += snmp_get_cpu_field(mib, i, offt);
1681 	return res;
1682 }
1683 EXPORT_SYMBOL_GPL(snmp_fold_field);
1684 
1685 #if BITS_PER_LONG==32
1686 
1687 u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offt,
1688 			 size_t syncp_offset)
1689 {
1690 	void *bhptr;
1691 	struct u64_stats_sync *syncp;
1692 	u64 v;
1693 	unsigned int start;
1694 
1695 	bhptr = per_cpu_ptr(mib, cpu);
1696 	syncp = (struct u64_stats_sync *)(bhptr + syncp_offset);
1697 	do {
1698 		start = u64_stats_fetch_begin_irq(syncp);
1699 		v = *(((u64 *)bhptr) + offt);
1700 	} while (u64_stats_fetch_retry_irq(syncp, start));
1701 
1702 	return v;
1703 }
1704 EXPORT_SYMBOL_GPL(snmp_get_cpu_field64);
1705 
1706 u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_offset)
1707 {
1708 	u64 res = 0;
1709 	int cpu;
1710 
1711 	for_each_possible_cpu(cpu) {
1712 		res += snmp_get_cpu_field64(mib, cpu, offt, syncp_offset);
1713 	}
1714 	return res;
1715 }
1716 EXPORT_SYMBOL_GPL(snmp_fold_field64);
1717 #endif
1718 
1719 #ifdef CONFIG_IP_MULTICAST
1720 static const struct net_protocol igmp_protocol = {
1721 	.handler =	igmp_rcv,
1722 	.netns_ok =	1,
1723 };
1724 #endif
1725 
1726 /* thinking of making this const? Don't.
1727  * early_demux can change based on sysctl.
1728  */
1729 static struct net_protocol tcp_protocol = {
1730 	.early_demux	=	tcp_v4_early_demux,
1731 	.early_demux_handler =  tcp_v4_early_demux,
1732 	.handler	=	tcp_v4_rcv,
1733 	.err_handler	=	tcp_v4_err,
1734 	.no_policy	=	1,
1735 	.netns_ok	=	1,
1736 	.icmp_strict_tag_validation = 1,
1737 };
1738 
1739 /* thinking of making this const? Don't.
1740  * early_demux can change based on sysctl.
1741  */
1742 static struct net_protocol udp_protocol = {
1743 	.early_demux =	udp_v4_early_demux,
1744 	.early_demux_handler =	udp_v4_early_demux,
1745 	.handler =	udp_rcv,
1746 	.err_handler =	udp_err,
1747 	.no_policy =	1,
1748 	.netns_ok =	1,
1749 };
1750 
1751 static const struct net_protocol icmp_protocol = {
1752 	.handler =	icmp_rcv,
1753 	.err_handler =	icmp_err,
1754 	.no_policy =	1,
1755 	.netns_ok =	1,
1756 };
1757 
1758 static __net_init int ipv4_mib_init_net(struct net *net)
1759 {
1760 	int i;
1761 
1762 	net->mib.tcp_statistics = alloc_percpu(struct tcp_mib);
1763 	if (!net->mib.tcp_statistics)
1764 		goto err_tcp_mib;
1765 	net->mib.ip_statistics = alloc_percpu(struct ipstats_mib);
1766 	if (!net->mib.ip_statistics)
1767 		goto err_ip_mib;
1768 
1769 	for_each_possible_cpu(i) {
1770 		struct ipstats_mib *af_inet_stats;
1771 		af_inet_stats = per_cpu_ptr(net->mib.ip_statistics, i);
1772 		u64_stats_init(&af_inet_stats->syncp);
1773 	}
1774 
1775 	net->mib.net_statistics = alloc_percpu(struct linux_mib);
1776 	if (!net->mib.net_statistics)
1777 		goto err_net_mib;
1778 	net->mib.udp_statistics = alloc_percpu(struct udp_mib);
1779 	if (!net->mib.udp_statistics)
1780 		goto err_udp_mib;
1781 	net->mib.udplite_statistics = alloc_percpu(struct udp_mib);
1782 	if (!net->mib.udplite_statistics)
1783 		goto err_udplite_mib;
1784 	net->mib.icmp_statistics = alloc_percpu(struct icmp_mib);
1785 	if (!net->mib.icmp_statistics)
1786 		goto err_icmp_mib;
1787 	net->mib.icmpmsg_statistics = kzalloc(sizeof(struct icmpmsg_mib),
1788 					      GFP_KERNEL);
1789 	if (!net->mib.icmpmsg_statistics)
1790 		goto err_icmpmsg_mib;
1791 
1792 	tcp_mib_init(net);
1793 	return 0;
1794 
1795 err_icmpmsg_mib:
1796 	free_percpu(net->mib.icmp_statistics);
1797 err_icmp_mib:
1798 	free_percpu(net->mib.udplite_statistics);
1799 err_udplite_mib:
1800 	free_percpu(net->mib.udp_statistics);
1801 err_udp_mib:
1802 	free_percpu(net->mib.net_statistics);
1803 err_net_mib:
1804 	free_percpu(net->mib.ip_statistics);
1805 err_ip_mib:
1806 	free_percpu(net->mib.tcp_statistics);
1807 err_tcp_mib:
1808 	return -ENOMEM;
1809 }
1810 
1811 static __net_exit void ipv4_mib_exit_net(struct net *net)
1812 {
1813 	kfree(net->mib.icmpmsg_statistics);
1814 	free_percpu(net->mib.icmp_statistics);
1815 	free_percpu(net->mib.udplite_statistics);
1816 	free_percpu(net->mib.udp_statistics);
1817 	free_percpu(net->mib.net_statistics);
1818 	free_percpu(net->mib.ip_statistics);
1819 	free_percpu(net->mib.tcp_statistics);
1820 #ifdef CONFIG_MPTCP
1821 	/* allocated on demand, see mptcp_init_sock() */
1822 	free_percpu(net->mib.mptcp_statistics);
1823 #endif
1824 }
1825 
1826 static __net_initdata struct pernet_operations ipv4_mib_ops = {
1827 	.init = ipv4_mib_init_net,
1828 	.exit = ipv4_mib_exit_net,
1829 };
1830 
1831 static int __init init_ipv4_mibs(void)
1832 {
1833 	return register_pernet_subsys(&ipv4_mib_ops);
1834 }
1835 
1836 static __net_init int inet_init_net(struct net *net)
1837 {
1838 	/*
1839 	 * Set defaults for local port range
1840 	 */
1841 	seqlock_init(&net->ipv4.ip_local_ports.lock);
1842 	net->ipv4.ip_local_ports.range[0] =  32768;
1843 	net->ipv4.ip_local_ports.range[1] =  60999;
1844 
1845 	seqlock_init(&net->ipv4.ping_group_range.lock);
1846 	/*
1847 	 * Sane defaults - nobody may create ping sockets.
1848 	 * Boot scripts should set this to distro-specific group.
1849 	 */
1850 	net->ipv4.ping_group_range.range[0] = make_kgid(&init_user_ns, 1);
1851 	net->ipv4.ping_group_range.range[1] = make_kgid(&init_user_ns, 0);
1852 
1853 	/* Default values for sysctl-controlled parameters.
1854 	 * We set them here, in case sysctl is not compiled.
1855 	 */
1856 	net->ipv4.sysctl_ip_default_ttl = IPDEFTTL;
1857 	net->ipv4.sysctl_ip_fwd_update_priority = 1;
1858 	net->ipv4.sysctl_ip_dynaddr = 0;
1859 	net->ipv4.sysctl_ip_early_demux = 1;
1860 	net->ipv4.sysctl_udp_early_demux = 1;
1861 	net->ipv4.sysctl_tcp_early_demux = 1;
1862 	net->ipv4.sysctl_nexthop_compat_mode = 1;
1863 #ifdef CONFIG_SYSCTL
1864 	net->ipv4.sysctl_ip_prot_sock = PROT_SOCK;
1865 #endif
1866 
1867 	/* Some igmp sysctl, whose values are always used */
1868 	net->ipv4.sysctl_igmp_max_memberships = 20;
1869 	net->ipv4.sysctl_igmp_max_msf = 10;
1870 	/* IGMP reports for link-local multicast groups are enabled by default */
1871 	net->ipv4.sysctl_igmp_llm_reports = 1;
1872 	net->ipv4.sysctl_igmp_qrv = 2;
1873 
1874 	return 0;
1875 }
1876 
1877 static __net_initdata struct pernet_operations af_inet_ops = {
1878 	.init = inet_init_net,
1879 };
1880 
1881 static int __init init_inet_pernet_ops(void)
1882 {
1883 	return register_pernet_subsys(&af_inet_ops);
1884 }
1885 
1886 static int ipv4_proc_init(void);
1887 
1888 /*
1889  *	IP protocol layer initialiser
1890  */
1891 
1892 static struct packet_offload ip_packet_offload __read_mostly = {
1893 	.type = cpu_to_be16(ETH_P_IP),
1894 	.callbacks = {
1895 		.gso_segment = inet_gso_segment,
1896 		.gro_receive = inet_gro_receive,
1897 		.gro_complete = inet_gro_complete,
1898 	},
1899 };
1900 
1901 static const struct net_offload ipip_offload = {
1902 	.callbacks = {
1903 		.gso_segment	= ipip_gso_segment,
1904 		.gro_receive	= ipip_gro_receive,
1905 		.gro_complete	= ipip_gro_complete,
1906 	},
1907 };
1908 
1909 static int __init ipip_offload_init(void)
1910 {
1911 	return inet_add_offload(&ipip_offload, IPPROTO_IPIP);
1912 }
1913 
1914 static int __init ipv4_offload_init(void)
1915 {
1916 	/*
1917 	 * Add offloads
1918 	 */
1919 	if (udpv4_offload_init() < 0)
1920 		pr_crit("%s: Cannot add UDP protocol offload\n", __func__);
1921 	if (tcpv4_offload_init() < 0)
1922 		pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
1923 	if (ipip_offload_init() < 0)
1924 		pr_crit("%s: Cannot add IPIP protocol offload\n", __func__);
1925 
1926 	dev_add_offload(&ip_packet_offload);
1927 	return 0;
1928 }
1929 
1930 fs_initcall(ipv4_offload_init);
1931 
1932 static struct packet_type ip_packet_type __read_mostly = {
1933 	.type = cpu_to_be16(ETH_P_IP),
1934 	.func = ip_rcv,
1935 	.list_func = ip_list_rcv,
1936 };
1937 
1938 static int __init inet_init(void)
1939 {
1940 	struct inet_protosw *q;
1941 	struct list_head *r;
1942 	int rc;
1943 
1944 	sock_skb_cb_check_size(sizeof(struct inet_skb_parm));
1945 
1946 	rc = proto_register(&tcp_prot, 1);
1947 	if (rc)
1948 		goto out;
1949 
1950 	rc = proto_register(&udp_prot, 1);
1951 	if (rc)
1952 		goto out_unregister_tcp_proto;
1953 
1954 	rc = proto_register(&raw_prot, 1);
1955 	if (rc)
1956 		goto out_unregister_udp_proto;
1957 
1958 	rc = proto_register(&ping_prot, 1);
1959 	if (rc)
1960 		goto out_unregister_raw_proto;
1961 
1962 	/*
1963 	 *	Tell SOCKET that we are alive...
1964 	 */
1965 
1966 	(void)sock_register(&inet_family_ops);
1967 
1968 #ifdef CONFIG_SYSCTL
1969 	ip_static_sysctl_init();
1970 #endif
1971 
1972 	/*
1973 	 *	Add all the base protocols.
1974 	 */
1975 
1976 	if (inet_add_protocol(&icmp_protocol, IPPROTO_ICMP) < 0)
1977 		pr_crit("%s: Cannot add ICMP protocol\n", __func__);
1978 	if (inet_add_protocol(&udp_protocol, IPPROTO_UDP) < 0)
1979 		pr_crit("%s: Cannot add UDP protocol\n", __func__);
1980 	if (inet_add_protocol(&tcp_protocol, IPPROTO_TCP) < 0)
1981 		pr_crit("%s: Cannot add TCP protocol\n", __func__);
1982 #ifdef CONFIG_IP_MULTICAST
1983 	if (inet_add_protocol(&igmp_protocol, IPPROTO_IGMP) < 0)
1984 		pr_crit("%s: Cannot add IGMP protocol\n", __func__);
1985 #endif
1986 
1987 	/* Register the socket-side information for inet_create. */
1988 	for (r = &inetsw[0]; r < &inetsw[SOCK_MAX]; ++r)
1989 		INIT_LIST_HEAD(r);
1990 
1991 	for (q = inetsw_array; q < &inetsw_array[INETSW_ARRAY_LEN]; ++q)
1992 		inet_register_protosw(q);
1993 
1994 	/*
1995 	 *	Set the ARP module up
1996 	 */
1997 
1998 	arp_init();
1999 
2000 	/*
2001 	 *	Set the IP module up
2002 	 */
2003 
2004 	ip_init();
2005 
2006 	/* Setup TCP slab cache for open requests. */
2007 	tcp_init();
2008 
2009 	/* Setup UDP memory threshold */
2010 	udp_init();
2011 
2012 	/* Add UDP-Lite (RFC 3828) */
2013 	udplite4_register();
2014 
2015 	raw_init();
2016 
2017 	ping_init();
2018 
2019 	/*
2020 	 *	Set the ICMP layer up
2021 	 */
2022 
2023 	if (icmp_init() < 0)
2024 		panic("Failed to create the ICMP control socket.\n");
2025 
2026 	/*
2027 	 *	Initialise the multicast router
2028 	 */
2029 #if defined(CONFIG_IP_MROUTE)
2030 	if (ip_mr_init())
2031 		pr_crit("%s: Cannot init ipv4 mroute\n", __func__);
2032 #endif
2033 
2034 	if (init_inet_pernet_ops())
2035 		pr_crit("%s: Cannot init ipv4 inet pernet ops\n", __func__);
2036 	/*
2037 	 *	Initialise per-cpu ipv4 mibs
2038 	 */
2039 
2040 	if (init_ipv4_mibs())
2041 		pr_crit("%s: Cannot init ipv4 mibs\n", __func__);
2042 
2043 	ipv4_proc_init();
2044 
2045 	ipfrag_init();
2046 
2047 	dev_add_pack(&ip_packet_type);
2048 
2049 	ip_tunnel_core_init();
2050 
2051 	rc = 0;
2052 out:
2053 	return rc;
2054 out_unregister_raw_proto:
2055 	proto_unregister(&raw_prot);
2056 out_unregister_udp_proto:
2057 	proto_unregister(&udp_prot);
2058 out_unregister_tcp_proto:
2059 	proto_unregister(&tcp_prot);
2060 	goto out;
2061 }
2062 
2063 fs_initcall(inet_init);
2064 
2065 /* ------------------------------------------------------------------------ */
2066 
2067 #ifdef CONFIG_PROC_FS
2068 static int __init ipv4_proc_init(void)
2069 {
2070 	int rc = 0;
2071 
2072 	if (raw_proc_init())
2073 		goto out_raw;
2074 	if (tcp4_proc_init())
2075 		goto out_tcp;
2076 	if (udp4_proc_init())
2077 		goto out_udp;
2078 	if (ping_proc_init())
2079 		goto out_ping;
2080 	if (ip_misc_proc_init())
2081 		goto out_misc;
2082 out:
2083 	return rc;
2084 out_misc:
2085 	ping_proc_exit();
2086 out_ping:
2087 	udp4_proc_exit();
2088 out_udp:
2089 	tcp4_proc_exit();
2090 out_tcp:
2091 	raw_proc_exit();
2092 out_raw:
2093 	rc = -ENOMEM;
2094 	goto out;
2095 }
2096 
2097 #else /* CONFIG_PROC_FS */
2098 static int __init ipv4_proc_init(void)
2099 {
2100 	return 0;
2101 }
2102 #endif /* CONFIG_PROC_FS */
2103