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Linux/net/ipv4/af_inet.c

  1 /*
  2  * INET         An implementation of the TCP/IP protocol suite for the LINUX
  3  *              operating system.  INET is implemented using the  BSD Socket
  4  *              interface as the means of communication with the user level.
  5  *
  6  *              PF_INET protocol family socket handler.
  7  *
  8  * Authors:     Ross Biro
  9  *              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
 10  *              Florian La Roche, <flla@stud.uni-sb.de>
 11  *              Alan Cox, <A.Cox@swansea.ac.uk>
 12  *
 13  * Changes (see also sock.c)
 14  *
 15  *              piggy,
 16  *              Karl Knutson    :       Socket protocol table
 17  *              A.N.Kuznetsov   :       Socket death error in accept().
 18  *              John Richardson :       Fix non blocking error in connect()
 19  *                                      so sockets that fail to connect
 20  *                                      don't return -EINPROGRESS.
 21  *              Alan Cox        :       Asynchronous I/O support
 22  *              Alan Cox        :       Keep correct socket pointer on sock
 23  *                                      structures
 24  *                                      when accept() ed
 25  *              Alan Cox        :       Semantics of SO_LINGER aren't state
 26  *                                      moved to close when you look carefully.
 27  *                                      With this fixed and the accept bug fixed
 28  *                                      some RPC stuff seems happier.
 29  *              Niibe Yutaka    :       4.4BSD style write async I/O
 30  *              Alan Cox,
 31  *              Tony Gale       :       Fixed reuse semantics.
 32  *              Alan Cox        :       bind() shouldn't abort existing but dead
 33  *                                      sockets. Stops FTP netin:.. I hope.
 34  *              Alan Cox        :       bind() works correctly for RAW sockets.
 35  *                                      Note that FreeBSD at least was broken
 36  *                                      in this respect so be careful with
 37  *                                      compatibility tests...
 38  *              Alan Cox        :       routing cache support
 39  *              Alan Cox        :       memzero the socket structure for
 40  *                                      compactness.
 41  *              Matt Day        :       nonblock connect error handler
 42  *              Alan Cox        :       Allow large numbers of pending sockets
 43  *                                      (eg for big web sites), but only if
 44  *                                      specifically application requested.
 45  *              Alan Cox        :       New buffering throughout IP. Used
 46  *                                      dumbly.
 47  *              Alan Cox        :       New buffering now used smartly.
 48  *              Alan Cox        :       BSD rather than common sense
 49  *                                      interpretation of listen.
 50  *              Germano Caronni :       Assorted small races.
 51  *              Alan Cox        :       sendmsg/recvmsg basic support.
 52  *              Alan Cox        :       Only sendmsg/recvmsg now supported.
 53  *              Alan Cox        :       Locked down bind (see security list).
 54  *              Alan Cox        :       Loosened bind a little.
 55  *              Mike McLagan    :       ADD/DEL DLCI Ioctls
 56  *      Willy Konynenberg       :       Transparent proxying support.
 57  *              David S. Miller :       New socket lookup architecture.
 58  *                                      Some other random speedups.
 59  *              Cyrus Durgin    :       Cleaned up file for kmod hacks.
 60  *              Andi Kleen      :       Fix inet_stream_connect TCP race.
 61  *
 62  *              This program is free software; you can redistribute it and/or
 63  *              modify it under the terms of the GNU General Public License
 64  *              as published by the Free Software Foundation; either version
 65  *              2 of the License, or (at your option) any later version.
 66  */
 67 
 68 #define pr_fmt(fmt) "IPv4: " fmt
 69 
 70 #include <linux/err.h>
 71 #include <linux/errno.h>
 72 #include <linux/types.h>
 73 #include <linux/socket.h>
 74 #include <linux/in.h>
 75 #include <linux/kernel.h>
 76 #include <linux/kmod.h>
 77 #include <linux/sched.h>
 78 #include <linux/timer.h>
 79 #include <linux/string.h>
 80 #include <linux/sockios.h>
 81 #include <linux/net.h>
 82 #include <linux/capability.h>
 83 #include <linux/fcntl.h>
 84 #include <linux/mm.h>
 85 #include <linux/interrupt.h>
 86 #include <linux/stat.h>
 87 #include <linux/init.h>
 88 #include <linux/poll.h>
 89 #include <linux/netfilter_ipv4.h>
 90 #include <linux/random.h>
 91 #include <linux/slab.h>
 92 
 93 #include <asm/uaccess.h>
 94 
 95 #include <linux/inet.h>
 96 #include <linux/igmp.h>
 97 #include <linux/inetdevice.h>
 98 #include <linux/netdevice.h>
 99 #include <net/checksum.h>
100 #include <net/ip.h>
101 #include <net/protocol.h>
102 #include <net/arp.h>
103 #include <net/route.h>
104 #include <net/ip_fib.h>
105 #include <net/inet_connection_sock.h>
106 #include <net/tcp.h>
107 #include <net/udp.h>
108 #include <net/udplite.h>
109 #include <net/ping.h>
110 #include <linux/skbuff.h>
111 #include <net/sock.h>
112 #include <net/raw.h>
113 #include <net/icmp.h>
114 #include <net/inet_common.h>
115 #include <net/ip_tunnels.h>
116 #include <net/xfrm.h>
117 #include <net/net_namespace.h>
118 #include <net/secure_seq.h>
119 #ifdef CONFIG_IP_MROUTE
120 #include <linux/mroute.h>
121 #endif
122 #include <net/l3mdev.h>
123 
124 
125 /* The inetsw table contains everything that inet_create needs to
126  * build a new socket.
127  */
128 static struct list_head inetsw[SOCK_MAX];
129 static DEFINE_SPINLOCK(inetsw_lock);
130 
131 /* New destruction routine */
132 
133 void inet_sock_destruct(struct sock *sk)
134 {
135         struct inet_sock *inet = inet_sk(sk);
136 
137         __skb_queue_purge(&sk->sk_receive_queue);
138         __skb_queue_purge(&sk->sk_error_queue);
139 
140         sk_mem_reclaim(sk);
141 
142         if (sk->sk_type == SOCK_STREAM && sk->sk_state != TCP_CLOSE) {
143                 pr_err("Attempt to release TCP socket in state %d %p\n",
144                        sk->sk_state, sk);
145                 return;
146         }
147         if (!sock_flag(sk, SOCK_DEAD)) {
148                 pr_err("Attempt to release alive inet socket %p\n", sk);
149                 return;
150         }
151 
152         WARN_ON(atomic_read(&sk->sk_rmem_alloc));
153         WARN_ON(atomic_read(&sk->sk_wmem_alloc));
154         WARN_ON(sk->sk_wmem_queued);
155         WARN_ON(sk->sk_forward_alloc);
156 
157         kfree(rcu_dereference_protected(inet->inet_opt, 1));
158         dst_release(rcu_dereference_check(sk->sk_dst_cache, 1));
159         dst_release(sk->sk_rx_dst);
160         sk_refcnt_debug_dec(sk);
161 }
162 EXPORT_SYMBOL(inet_sock_destruct);
163 
164 /*
165  *      The routines beyond this point handle the behaviour of an AF_INET
166  *      socket object. Mostly it punts to the subprotocols of IP to do
167  *      the work.
168  */
169 
170 /*
171  *      Automatically bind an unbound socket.
172  */
173 
174 static int inet_autobind(struct sock *sk)
175 {
176         struct inet_sock *inet;
177         /* We may need to bind the socket. */
178         lock_sock(sk);
179         inet = inet_sk(sk);
180         if (!inet->inet_num) {
181                 if (sk->sk_prot->get_port(sk, 0)) {
182                         release_sock(sk);
183                         return -EAGAIN;
184                 }
185                 inet->inet_sport = htons(inet->inet_num);
186         }
187         release_sock(sk);
188         return 0;
189 }
190 
191 /*
192  *      Move a socket into listening state.
193  */
194 int inet_listen(struct socket *sock, int backlog)
195 {
196         struct sock *sk = sock->sk;
197         unsigned char old_state;
198         int err;
199 
200         lock_sock(sk);
201 
202         err = -EINVAL;
203         if (sock->state != SS_UNCONNECTED || sock->type != SOCK_STREAM)
204                 goto out;
205 
206         old_state = sk->sk_state;
207         if (!((1 << old_state) & (TCPF_CLOSE | TCPF_LISTEN)))
208                 goto out;
209 
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                 if ((sysctl_tcp_fastopen & TFO_SERVER_WO_SOCKOPT1) &&
221                     (sysctl_tcp_fastopen & TFO_SERVER_ENABLE) &&
222                     !inet_csk(sk)->icsk_accept_queue.fastopenq.max_qlen) {
223                         fastopen_queue_tune(sk, backlog);
224                         tcp_fastopen_init_key_once(true);
225                 }
226 
227                 err = inet_csk_listen_start(sk, backlog);
228                 if (err)
229                         goto out;
230         }
231         sk->sk_max_ack_backlog = backlog;
232         err = 0;
233 
234 out:
235         release_sock(sk);
236         return err;
237 }
238 EXPORT_SYMBOL(inet_listen);
239 
240 /*
241  *      Create an inet socket.
242  */
243 
244 static int inet_create(struct net *net, struct socket *sock, int protocol,
245                        int kern)
246 {
247         struct sock *sk;
248         struct inet_protosw *answer;
249         struct inet_sock *inet;
250         struct proto *answer_prot;
251         unsigned char answer_flags;
252         int try_loading_module = 0;
253         int err;
254 
255         if (protocol < 0 || protocol >= IPPROTO_MAX)
256                 return -EINVAL;
257 
258         sock->state = SS_UNCONNECTED;
259 
260         /* Look for the requested type/protocol pair. */
261 lookup_protocol:
262         err = -ESOCKTNOSUPPORT;
263         rcu_read_lock();
264         list_for_each_entry_rcu(answer, &inetsw[sock->type], list) {
265 
266                 err = 0;
267                 /* Check the non-wild match. */
268                 if (protocol == answer->protocol) {
269                         if (protocol != IPPROTO_IP)
270                                 break;
271                 } else {
272                         /* Check for the two wild cases. */
273                         if (IPPROTO_IP == protocol) {
274                                 protocol = answer->protocol;
275                                 break;
276                         }
277                         if (IPPROTO_IP == answer->protocol)
278                                 break;
279                 }
280                 err = -EPROTONOSUPPORT;
281         }
282 
283         if (unlikely(err)) {
284                 if (try_loading_module < 2) {
285                         rcu_read_unlock();
286                         /*
287                          * Be more specific, e.g. net-pf-2-proto-132-type-1
288                          * (net-pf-PF_INET-proto-IPPROTO_SCTP-type-SOCK_STREAM)
289                          */
290                         if (++try_loading_module == 1)
291                                 request_module("net-pf-%d-proto-%d-type-%d",
292                                                PF_INET, protocol, sock->type);
293                         /*
294                          * Fall back to generic, e.g. net-pf-2-proto-132
295                          * (net-pf-PF_INET-proto-IPPROTO_SCTP)
296                          */
297                         else
298                                 request_module("net-pf-%d-proto-%d",
299                                                PF_INET, protocol);
300                         goto lookup_protocol;
301                 } else
302                         goto out_rcu_unlock;
303         }
304 
305         err = -EPERM;
306         if (sock->type == SOCK_RAW && !kern &&
307             !ns_capable(net->user_ns, CAP_NET_RAW))
308                 goto out_rcu_unlock;
309 
310         sock->ops = answer->ops;
311         answer_prot = answer->prot;
312         answer_flags = answer->flags;
313         rcu_read_unlock();
314 
315         WARN_ON(!answer_prot->slab);
316 
317         err = -ENOBUFS;
318         sk = sk_alloc(net, PF_INET, GFP_KERNEL, answer_prot, kern);
319         if (!sk)
320                 goto out;
321 
322         err = 0;
323         if (INET_PROTOSW_REUSE & answer_flags)
324                 sk->sk_reuse = SK_CAN_REUSE;
325 
326         inet = inet_sk(sk);
327         inet->is_icsk = (INET_PROTOSW_ICSK & answer_flags) != 0;
328 
329         inet->nodefrag = 0;
330 
331         if (SOCK_RAW == sock->type) {
332                 inet->inet_num = protocol;
333                 if (IPPROTO_RAW == protocol)
334                         inet->hdrincl = 1;
335         }
336 
337         if (net->ipv4.sysctl_ip_no_pmtu_disc)
338                 inet->pmtudisc = IP_PMTUDISC_DONT;
339         else
340                 inet->pmtudisc = IP_PMTUDISC_WANT;
341 
342         inet->inet_id = 0;
343 
344         sock_init_data(sock, sk);
345 
346         sk->sk_destruct    = inet_sock_destruct;
347         sk->sk_protocol    = protocol;
348         sk->sk_backlog_rcv = sk->sk_prot->backlog_rcv;
349 
350         inet->uc_ttl    = -1;
351         inet->mc_loop   = 1;
352         inet->mc_ttl    = 1;
353         inet->mc_all    = 1;
354         inet->mc_index  = 0;
355         inet->mc_list   = NULL;
356         inet->rcv_tos   = 0;
357 
358         sk_refcnt_debug_inc(sk);
359 
360         if (inet->inet_num) {
361                 /* It assumes that any protocol which allows
362                  * the user to assign a number at socket
363                  * creation time automatically
364                  * shares.
365                  */
366                 inet->inet_sport = htons(inet->inet_num);
367                 /* Add to protocol hash chains. */
368                 err = sk->sk_prot->hash(sk);
369                 if (err) {
370                         sk_common_release(sk);
371                         goto out;
372                 }
373         }
374 
375         if (sk->sk_prot->init) {
376                 err = sk->sk_prot->init(sk);
377                 if (err)
378                         sk_common_release(sk);
379         }
380 out:
381         return err;
382 out_rcu_unlock:
383         rcu_read_unlock();
384         goto out;
385 }
386 
387 
388 /*
389  *      The peer socket should always be NULL (or else). When we call this
390  *      function we are destroying the object and from then on nobody
391  *      should refer to it.
392  */
393 int inet_release(struct socket *sock)
394 {
395         struct sock *sk = sock->sk;
396 
397         if (sk) {
398                 long timeout;
399 
400                 /* Applications forget to leave groups before exiting */
401                 ip_mc_drop_socket(sk);
402 
403                 /* If linger is set, we don't return until the close
404                  * is complete.  Otherwise we return immediately. The
405                  * actually closing is done the same either way.
406                  *
407                  * If the close is due to the process exiting, we never
408                  * linger..
409                  */
410                 timeout = 0;
411                 if (sock_flag(sk, SOCK_LINGER) &&
412                     !(current->flags & PF_EXITING))
413                         timeout = sk->sk_lingertime;
414                 sock->sk = NULL;
415                 sk->sk_prot->close(sk, timeout);
416         }
417         return 0;
418 }
419 EXPORT_SYMBOL(inet_release);
420 
421 int inet_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len)
422 {
423         struct sockaddr_in *addr = (struct sockaddr_in *)uaddr;
424         struct sock *sk = sock->sk;
425         struct inet_sock *inet = inet_sk(sk);
426         struct net *net = sock_net(sk);
427         unsigned short snum;
428         int chk_addr_ret;
429         u32 tb_id = RT_TABLE_LOCAL;
430         int err;
431 
432         /* If the socket has its own bind function then use it. (RAW) */
433         if (sk->sk_prot->bind) {
434                 err = sk->sk_prot->bind(sk, uaddr, addr_len);
435                 goto out;
436         }
437         err = -EINVAL;
438         if (addr_len < sizeof(struct sockaddr_in))
439                 goto out;
440 
441         if (addr->sin_family != AF_INET) {
442                 /* Compatibility games : accept AF_UNSPEC (mapped to AF_INET)
443                  * only if s_addr is INADDR_ANY.
444                  */
445                 err = -EAFNOSUPPORT;
446                 if (addr->sin_family != AF_UNSPEC ||
447                     addr->sin_addr.s_addr != htonl(INADDR_ANY))
448                         goto out;
449         }
450 
451         tb_id = l3mdev_fib_table_by_index(net, sk->sk_bound_dev_if) ? : tb_id;
452         chk_addr_ret = inet_addr_type_table(net, addr->sin_addr.s_addr, tb_id);
453 
454         /* Not specified by any standard per-se, however it breaks too
455          * many applications when removed.  It is unfortunate since
456          * allowing applications to make a non-local bind solves
457          * several problems with systems using dynamic addressing.
458          * (ie. your servers still start up even if your ISDN link
459          *  is temporarily down)
460          */
461         err = -EADDRNOTAVAIL;
462         if (!net->ipv4.sysctl_ip_nonlocal_bind &&
463             !(inet->freebind || inet->transparent) &&
464             addr->sin_addr.s_addr != htonl(INADDR_ANY) &&
465             chk_addr_ret != RTN_LOCAL &&
466             chk_addr_ret != RTN_MULTICAST &&
467             chk_addr_ret != RTN_BROADCAST)
468                 goto out;
469 
470         snum = ntohs(addr->sin_port);
471         err = -EACCES;
472         if (snum && snum < PROT_SOCK &&
473             !ns_capable(net->user_ns, CAP_NET_BIND_SERVICE))
474                 goto out;
475 
476         /*      We keep a pair of addresses. rcv_saddr is the one
477          *      used by hash lookups, and saddr is used for transmit.
478          *
479          *      In the BSD API these are the same except where it
480          *      would be illegal to use them (multicast/broadcast) in
481          *      which case the sending device address is used.
482          */
483         lock_sock(sk);
484 
485         /* Check these errors (active socket, double bind). */
486         err = -EINVAL;
487         if (sk->sk_state != TCP_CLOSE || inet->inet_num)
488                 goto out_release_sock;
489 
490         inet->inet_rcv_saddr = inet->inet_saddr = addr->sin_addr.s_addr;
491         if (chk_addr_ret == RTN_MULTICAST || chk_addr_ret == RTN_BROADCAST)
492                 inet->inet_saddr = 0;  /* Use device */
493 
494         /* Make sure we are allowed to bind here. */
495         if ((snum || !inet->bind_address_no_port) &&
496             sk->sk_prot->get_port(sk, snum)) {
497                 inet->inet_saddr = inet->inet_rcv_saddr = 0;
498                 err = -EADDRINUSE;
499                 goto out_release_sock;
500         }
501 
502         if (inet->inet_rcv_saddr)
503                 sk->sk_userlocks |= SOCK_BINDADDR_LOCK;
504         if (snum)
505                 sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
506         inet->inet_sport = htons(inet->inet_num);
507         inet->inet_daddr = 0;
508         inet->inet_dport = 0;
509         sk_dst_reset(sk);
510         err = 0;
511 out_release_sock:
512         release_sock(sk);
513 out:
514         return err;
515 }
516 EXPORT_SYMBOL(inet_bind);
517 
518 int inet_dgram_connect(struct socket *sock, struct sockaddr *uaddr,
519                        int addr_len, int flags)
520 {
521         struct sock *sk = sock->sk;
522 
523         if (addr_len < sizeof(uaddr->sa_family))
524                 return -EINVAL;
525         if (uaddr->sa_family == AF_UNSPEC)
526                 return sk->sk_prot->disconnect(sk, flags);
527 
528         if (!inet_sk(sk)->inet_num && inet_autobind(sk))
529                 return -EAGAIN;
530         return sk->sk_prot->connect(sk, uaddr, addr_len);
531 }
532 EXPORT_SYMBOL(inet_dgram_connect);
533 
534 static long inet_wait_for_connect(struct sock *sk, long timeo, int writebias)
535 {
536         DEFINE_WAIT_FUNC(wait, woken_wake_function);
537 
538         add_wait_queue(sk_sleep(sk), &wait);
539         sk->sk_write_pending += writebias;
540 
541         /* Basic assumption: if someone sets sk->sk_err, he _must_
542          * change state of the socket from TCP_SYN_*.
543          * Connect() does not allow to get error notifications
544          * without closing the socket.
545          */
546         while ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
547                 release_sock(sk);
548                 timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
549                 lock_sock(sk);
550                 if (signal_pending(current) || !timeo)
551                         break;
552         }
553         remove_wait_queue(sk_sleep(sk), &wait);
554         sk->sk_write_pending -= writebias;
555         return timeo;
556 }
557 
558 /*
559  *      Connect to a remote host. There is regrettably still a little
560  *      TCP 'magic' in here.
561  */
562 int __inet_stream_connect(struct socket *sock, struct sockaddr *uaddr,
563                           int addr_len, int flags)
564 {
565         struct sock *sk = sock->sk;
566         int err;
567         long timeo;
568 
569         if (addr_len < sizeof(uaddr->sa_family))
570                 return -EINVAL;
571 
572         if (uaddr->sa_family == AF_UNSPEC) {
573                 err = sk->sk_prot->disconnect(sk, flags);
574                 sock->state = err ? SS_DISCONNECTING : SS_UNCONNECTED;
575                 goto out;
576         }
577 
578         switch (sock->state) {
579         default:
580                 err = -EINVAL;
581                 goto out;
582         case SS_CONNECTED:
583                 err = -EISCONN;
584                 goto out;
585         case SS_CONNECTING:
586                 err = -EALREADY;
587                 /* Fall out of switch with err, set for this state */
588                 break;
589         case SS_UNCONNECTED:
590                 err = -EISCONN;
591                 if (sk->sk_state != TCP_CLOSE)
592                         goto out;
593 
594                 err = sk->sk_prot->connect(sk, uaddr, addr_len);
595                 if (err < 0)
596                         goto out;
597 
598                 sock->state = SS_CONNECTING;
599 
600                 /* Just entered SS_CONNECTING state; the only
601                  * difference is that return value in non-blocking
602                  * case is EINPROGRESS, rather than EALREADY.
603                  */
604                 err = -EINPROGRESS;
605                 break;
606         }
607 
608         timeo = sock_sndtimeo(sk, flags & O_NONBLOCK);
609 
610         if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
611                 int writebias = (sk->sk_protocol == IPPROTO_TCP) &&
612                                 tcp_sk(sk)->fastopen_req &&
613                                 tcp_sk(sk)->fastopen_req->data ? 1 : 0;
614 
615                 /* Error code is set above */
616                 if (!timeo || !inet_wait_for_connect(sk, timeo, writebias))
617                         goto out;
618 
619                 err = sock_intr_errno(timeo);
620                 if (signal_pending(current))
621                         goto out;
622         }
623 
624         /* Connection was closed by RST, timeout, ICMP error
625          * or another process disconnected us.
626          */
627         if (sk->sk_state == TCP_CLOSE)
628                 goto sock_error;
629 
630         /* sk->sk_err may be not zero now, if RECVERR was ordered by user
631          * and error was received after socket entered established state.
632          * Hence, it is handled normally after connect() return successfully.
633          */
634 
635         sock->state = SS_CONNECTED;
636         err = 0;
637 out:
638         return err;
639 
640 sock_error:
641         err = sock_error(sk) ? : -ECONNABORTED;
642         sock->state = SS_UNCONNECTED;
643         if (sk->sk_prot->disconnect(sk, flags))
644                 sock->state = SS_DISCONNECTING;
645         goto out;
646 }
647 EXPORT_SYMBOL(__inet_stream_connect);
648 
649 int inet_stream_connect(struct socket *sock, struct sockaddr *uaddr,
650                         int addr_len, int flags)
651 {
652         int err;
653 
654         lock_sock(sock->sk);
655         err = __inet_stream_connect(sock, uaddr, addr_len, flags);
656         release_sock(sock->sk);
657         return err;
658 }
659 EXPORT_SYMBOL(inet_stream_connect);
660 
661 /*
662  *      Accept a pending connection. The TCP layer now gives BSD semantics.
663  */
664 
665 int inet_accept(struct socket *sock, struct socket *newsock, int flags)
666 {
667         struct sock *sk1 = sock->sk;
668         int err = -EINVAL;
669         struct sock *sk2 = sk1->sk_prot->accept(sk1, flags, &err);
670 
671         if (!sk2)
672                 goto do_err;
673 
674         lock_sock(sk2);
675 
676         sock_rps_record_flow(sk2);
677         WARN_ON(!((1 << sk2->sk_state) &
678                   (TCPF_ESTABLISHED | TCPF_SYN_RECV |
679                   TCPF_CLOSE_WAIT | TCPF_CLOSE)));
680 
681         sock_graft(sk2, newsock);
682 
683         newsock->state = SS_CONNECTED;
684         err = 0;
685         release_sock(sk2);
686 do_err:
687         return err;
688 }
689 EXPORT_SYMBOL(inet_accept);
690 
691 
692 /*
693  *      This does both peername and sockname.
694  */
695 int inet_getname(struct socket *sock, struct sockaddr *uaddr,
696                         int *uaddr_len, int peer)
697 {
698         struct sock *sk         = sock->sk;
699         struct inet_sock *inet  = inet_sk(sk);
700         DECLARE_SOCKADDR(struct sockaddr_in *, sin, uaddr);
701 
702         sin->sin_family = AF_INET;
703         if (peer) {
704                 if (!inet->inet_dport ||
705                     (((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_SYN_SENT)) &&
706                      peer == 1))
707                         return -ENOTCONN;
708                 sin->sin_port = inet->inet_dport;
709                 sin->sin_addr.s_addr = inet->inet_daddr;
710         } else {
711                 __be32 addr = inet->inet_rcv_saddr;
712                 if (!addr)
713                         addr = inet->inet_saddr;
714                 sin->sin_port = inet->inet_sport;
715                 sin->sin_addr.s_addr = addr;
716         }
717         memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
718         *uaddr_len = sizeof(*sin);
719         return 0;
720 }
721 EXPORT_SYMBOL(inet_getname);
722 
723 int inet_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
724 {
725         struct sock *sk = sock->sk;
726 
727         sock_rps_record_flow(sk);
728 
729         /* We may need to bind the socket. */
730         if (!inet_sk(sk)->inet_num && !sk->sk_prot->no_autobind &&
731             inet_autobind(sk))
732                 return -EAGAIN;
733 
734         return sk->sk_prot->sendmsg(sk, msg, size);
735 }
736 EXPORT_SYMBOL(inet_sendmsg);
737 
738 ssize_t inet_sendpage(struct socket *sock, struct page *page, int offset,
739                       size_t size, int flags)
740 {
741         struct sock *sk = sock->sk;
742 
743         sock_rps_record_flow(sk);
744 
745         /* We may need to bind the socket. */
746         if (!inet_sk(sk)->inet_num && !sk->sk_prot->no_autobind &&
747             inet_autobind(sk))
748                 return -EAGAIN;
749 
750         if (sk->sk_prot->sendpage)
751                 return sk->sk_prot->sendpage(sk, page, offset, size, flags);
752         return sock_no_sendpage(sock, page, offset, size, flags);
753 }
754 EXPORT_SYMBOL(inet_sendpage);
755 
756 int inet_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
757                  int flags)
758 {
759         struct sock *sk = sock->sk;
760         int addr_len = 0;
761         int err;
762 
763         sock_rps_record_flow(sk);
764 
765         err = sk->sk_prot->recvmsg(sk, msg, size, flags & MSG_DONTWAIT,
766                                    flags & ~MSG_DONTWAIT, &addr_len);
767         if (err >= 0)
768                 msg->msg_namelen = addr_len;
769         return err;
770 }
771 EXPORT_SYMBOL(inet_recvmsg);
772 
773 int inet_shutdown(struct socket *sock, int how)
774 {
775         struct sock *sk = sock->sk;
776         int err = 0;
777 
778         /* This should really check to make sure
779          * the socket is a TCP socket. (WHY AC...)
780          */
781         how++; /* maps 0->1 has the advantage of making bit 1 rcvs and
782                        1->2 bit 2 snds.
783                        2->3 */
784         if ((how & ~SHUTDOWN_MASK) || !how)     /* MAXINT->0 */
785                 return -EINVAL;
786 
787         lock_sock(sk);
788         if (sock->state == SS_CONNECTING) {
789                 if ((1 << sk->sk_state) &
790                     (TCPF_SYN_SENT | TCPF_SYN_RECV | TCPF_CLOSE))
791                         sock->state = SS_DISCONNECTING;
792                 else
793                         sock->state = SS_CONNECTED;
794         }
795 
796         switch (sk->sk_state) {
797         case TCP_CLOSE:
798                 err = -ENOTCONN;
799                 /* Hack to wake up other listeners, who can poll for
800                    POLLHUP, even on eg. unconnected UDP sockets -- RR */
801         default:
802                 sk->sk_shutdown |= how;
803                 if (sk->sk_prot->shutdown)
804                         sk->sk_prot->shutdown(sk, how);
805                 break;
806 
807         /* Remaining two branches are temporary solution for missing
808          * close() in multithreaded environment. It is _not_ a good idea,
809          * but we have no choice until close() is repaired at VFS level.
810          */
811         case TCP_LISTEN:
812                 if (!(how & RCV_SHUTDOWN))
813                         break;
814                 /* Fall through */
815         case TCP_SYN_SENT:
816                 err = sk->sk_prot->disconnect(sk, O_NONBLOCK);
817                 sock->state = err ? SS_DISCONNECTING : SS_UNCONNECTED;
818                 break;
819         }
820 
821         /* Wake up anyone sleeping in poll. */
822         sk->sk_state_change(sk);
823         release_sock(sk);
824         return err;
825 }
826 EXPORT_SYMBOL(inet_shutdown);
827 
828 /*
829  *      ioctl() calls you can issue on an INET socket. Most of these are
830  *      device configuration and stuff and very rarely used. Some ioctls
831  *      pass on to the socket itself.
832  *
833  *      NOTE: I like the idea of a module for the config stuff. ie ifconfig
834  *      loads the devconfigure module does its configuring and unloads it.
835  *      There's a good 20K of config code hanging around the kernel.
836  */
837 
838 int inet_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
839 {
840         struct sock *sk = sock->sk;
841         int err = 0;
842         struct net *net = sock_net(sk);
843 
844         switch (cmd) {
845         case SIOCGSTAMP:
846                 err = sock_get_timestamp(sk, (struct timeval __user *)arg);
847                 break;
848         case SIOCGSTAMPNS:
849                 err = sock_get_timestampns(sk, (struct timespec __user *)arg);
850                 break;
851         case SIOCADDRT:
852         case SIOCDELRT:
853         case SIOCRTMSG:
854                 err = ip_rt_ioctl(net, cmd, (void __user *)arg);
855                 break;
856         case SIOCDARP:
857         case SIOCGARP:
858         case SIOCSARP:
859                 err = arp_ioctl(net, cmd, (void __user *)arg);
860                 break;
861         case SIOCGIFADDR:
862         case SIOCSIFADDR:
863         case SIOCGIFBRDADDR:
864         case SIOCSIFBRDADDR:
865         case SIOCGIFNETMASK:
866         case SIOCSIFNETMASK:
867         case SIOCGIFDSTADDR:
868         case SIOCSIFDSTADDR:
869         case SIOCSIFPFLAGS:
870         case SIOCGIFPFLAGS:
871         case SIOCSIFFLAGS:
872                 err = devinet_ioctl(net, cmd, (void __user *)arg);
873                 break;
874         default:
875                 if (sk->sk_prot->ioctl)
876                         err = sk->sk_prot->ioctl(sk, cmd, arg);
877                 else
878                         err = -ENOIOCTLCMD;
879                 break;
880         }
881         return err;
882 }
883 EXPORT_SYMBOL(inet_ioctl);
884 
885 #ifdef CONFIG_COMPAT
886 static int inet_compat_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
887 {
888         struct sock *sk = sock->sk;
889         int err = -ENOIOCTLCMD;
890 
891         if (sk->sk_prot->compat_ioctl)
892                 err = sk->sk_prot->compat_ioctl(sk, cmd, arg);
893 
894         return err;
895 }
896 #endif
897 
898 const struct proto_ops inet_stream_ops = {
899         .family            = PF_INET,
900         .owner             = THIS_MODULE,
901         .release           = inet_release,
902         .bind              = inet_bind,
903         .connect           = inet_stream_connect,
904         .socketpair        = sock_no_socketpair,
905         .accept            = inet_accept,
906         .getname           = inet_getname,
907         .poll              = tcp_poll,
908         .ioctl             = inet_ioctl,
909         .listen            = inet_listen,
910         .shutdown          = inet_shutdown,
911         .setsockopt        = sock_common_setsockopt,
912         .getsockopt        = sock_common_getsockopt,
913         .sendmsg           = inet_sendmsg,
914         .recvmsg           = inet_recvmsg,
915         .mmap              = sock_no_mmap,
916         .sendpage          = inet_sendpage,
917         .splice_read       = tcp_splice_read,
918         .read_sock         = tcp_read_sock,
919         .peek_len          = tcp_peek_len,
920 #ifdef CONFIG_COMPAT
921         .compat_setsockopt = compat_sock_common_setsockopt,
922         .compat_getsockopt = compat_sock_common_getsockopt,
923         .compat_ioctl      = inet_compat_ioctl,
924 #endif
925 };
926 EXPORT_SYMBOL(inet_stream_ops);
927 
928 const struct proto_ops inet_dgram_ops = {
929         .family            = PF_INET,
930         .owner             = THIS_MODULE,
931         .release           = inet_release,
932         .bind              = inet_bind,
933         .connect           = inet_dgram_connect,
934         .socketpair        = sock_no_socketpair,
935         .accept            = sock_no_accept,
936         .getname           = inet_getname,
937         .poll              = udp_poll,
938         .ioctl             = inet_ioctl,
939         .listen            = sock_no_listen,
940         .shutdown          = inet_shutdown,
941         .setsockopt        = sock_common_setsockopt,
942         .getsockopt        = sock_common_getsockopt,
943         .sendmsg           = inet_sendmsg,
944         .recvmsg           = inet_recvmsg,
945         .mmap              = sock_no_mmap,
946         .sendpage          = inet_sendpage,
947         .set_peek_off      = sk_set_peek_off,
948 #ifdef CONFIG_COMPAT
949         .compat_setsockopt = compat_sock_common_setsockopt,
950         .compat_getsockopt = compat_sock_common_getsockopt,
951         .compat_ioctl      = inet_compat_ioctl,
952 #endif
953 };
954 EXPORT_SYMBOL(inet_dgram_ops);
955 
956 /*
957  * For SOCK_RAW sockets; should be the same as inet_dgram_ops but without
958  * udp_poll
959  */
960 static const struct proto_ops inet_sockraw_ops = {
961         .family            = PF_INET,
962         .owner             = THIS_MODULE,
963         .release           = inet_release,
964         .bind              = inet_bind,
965         .connect           = inet_dgram_connect,
966         .socketpair        = sock_no_socketpair,
967         .accept            = sock_no_accept,
968         .getname           = inet_getname,
969         .poll              = datagram_poll,
970         .ioctl             = inet_ioctl,
971         .listen            = sock_no_listen,
972         .shutdown          = inet_shutdown,
973         .setsockopt        = sock_common_setsockopt,
974         .getsockopt        = sock_common_getsockopt,
975         .sendmsg           = inet_sendmsg,
976         .recvmsg           = inet_recvmsg,
977         .mmap              = sock_no_mmap,
978         .sendpage          = inet_sendpage,
979 #ifdef CONFIG_COMPAT
980         .compat_setsockopt = compat_sock_common_setsockopt,
981         .compat_getsockopt = compat_sock_common_getsockopt,
982         .compat_ioctl      = inet_compat_ioctl,
983 #endif
984 };
985 
986 static const struct net_proto_family inet_family_ops = {
987         .family = PF_INET,
988         .create = inet_create,
989         .owner  = THIS_MODULE,
990 };
991 
992 /* Upon startup we insert all the elements in inetsw_array[] into
993  * the linked list inetsw.
994  */
995 static struct inet_protosw inetsw_array[] =
996 {
997         {
998                 .type =       SOCK_STREAM,
999                 .protocol =   IPPROTO_TCP,
1000                 .prot =       &tcp_prot,
1001                 .ops =        &inet_stream_ops,
1002                 .flags =      INET_PROTOSW_PERMANENT |
1003                               INET_PROTOSW_ICSK,
1004         },
1005 
1006         {
1007                 .type =       SOCK_DGRAM,
1008                 .protocol =   IPPROTO_UDP,
1009                 .prot =       &udp_prot,
1010                 .ops =        &inet_dgram_ops,
1011                 .flags =      INET_PROTOSW_PERMANENT,
1012        },
1013 
1014        {
1015                 .type =       SOCK_DGRAM,
1016                 .protocol =   IPPROTO_ICMP,
1017                 .prot =       &ping_prot,
1018                 .ops =        &inet_dgram_ops,
1019                 .flags =      INET_PROTOSW_REUSE,
1020        },
1021 
1022        {
1023                .type =       SOCK_RAW,
1024                .protocol =   IPPROTO_IP,        /* wild card */
1025                .prot =       &raw_prot,
1026                .ops =        &inet_sockraw_ops,
1027                .flags =      INET_PROTOSW_REUSE,
1028        }
1029 };
1030 
1031 #define INETSW_ARRAY_LEN ARRAY_SIZE(inetsw_array)
1032 
1033 void inet_register_protosw(struct inet_protosw *p)
1034 {
1035         struct list_head *lh;
1036         struct inet_protosw *answer;
1037         int protocol = p->protocol;
1038         struct list_head *last_perm;
1039 
1040         spin_lock_bh(&inetsw_lock);
1041 
1042         if (p->type >= SOCK_MAX)
1043                 goto out_illegal;
1044 
1045         /* If we are trying to override a permanent protocol, bail. */
1046         last_perm = &inetsw[p->type];
1047         list_for_each(lh, &inetsw[p->type]) {
1048                 answer = list_entry(lh, struct inet_protosw, list);
1049                 /* Check only the non-wild match. */
1050                 if ((INET_PROTOSW_PERMANENT & answer->flags) == 0)
1051                         break;
1052                 if (protocol == answer->protocol)
1053                         goto out_permanent;
1054                 last_perm = lh;
1055         }
1056 
1057         /* Add the new entry after the last permanent entry if any, so that
1058          * the new entry does not override a permanent entry when matched with
1059          * a wild-card protocol. But it is allowed to override any existing
1060          * non-permanent entry.  This means that when we remove this entry, the
1061          * system automatically returns to the old behavior.
1062          */
1063         list_add_rcu(&p->list, last_perm);
1064 out:
1065         spin_unlock_bh(&inetsw_lock);
1066 
1067         return;
1068 
1069 out_permanent:
1070         pr_err("Attempt to override permanent protocol %d\n", protocol);
1071         goto out;
1072 
1073 out_illegal:
1074         pr_err("Ignoring attempt to register invalid socket type %d\n",
1075                p->type);
1076         goto out;
1077 }
1078 EXPORT_SYMBOL(inet_register_protosw);
1079 
1080 void inet_unregister_protosw(struct inet_protosw *p)
1081 {
1082         if (INET_PROTOSW_PERMANENT & p->flags) {
1083                 pr_err("Attempt to unregister permanent protocol %d\n",
1084                        p->protocol);
1085         } else {
1086                 spin_lock_bh(&inetsw_lock);
1087                 list_del_rcu(&p->list);
1088                 spin_unlock_bh(&inetsw_lock);
1089 
1090                 synchronize_net();
1091         }
1092 }
1093 EXPORT_SYMBOL(inet_unregister_protosw);
1094 
1095 static int inet_sk_reselect_saddr(struct sock *sk)
1096 {
1097         struct inet_sock *inet = inet_sk(sk);
1098         __be32 old_saddr = inet->inet_saddr;
1099         __be32 daddr = inet->inet_daddr;
1100         struct flowi4 *fl4;
1101         struct rtable *rt;
1102         __be32 new_saddr;
1103         struct ip_options_rcu *inet_opt;
1104 
1105         inet_opt = rcu_dereference_protected(inet->inet_opt,
1106                                              lockdep_sock_is_held(sk));
1107         if (inet_opt && inet_opt->opt.srr)
1108                 daddr = inet_opt->opt.faddr;
1109 
1110         /* Query new route. */
1111         fl4 = &inet->cork.fl.u.ip4;
1112         rt = ip_route_connect(fl4, daddr, 0, RT_CONN_FLAGS(sk),
1113                               sk->sk_bound_dev_if, sk->sk_protocol,
1114                               inet->inet_sport, inet->inet_dport, sk);
1115         if (IS_ERR(rt))
1116                 return PTR_ERR(rt);
1117 
1118         sk_setup_caps(sk, &rt->dst);
1119 
1120         new_saddr = fl4->saddr;
1121 
1122         if (new_saddr == old_saddr)
1123                 return 0;
1124 
1125         if (sock_net(sk)->ipv4.sysctl_ip_dynaddr > 1) {
1126                 pr_info("%s(): shifting inet->saddr from %pI4 to %pI4\n",
1127                         __func__, &old_saddr, &new_saddr);
1128         }
1129 
1130         inet->inet_saddr = inet->inet_rcv_saddr = new_saddr;
1131 
1132         /*
1133          * XXX The only one ugly spot where we need to
1134          * XXX really change the sockets identity after
1135          * XXX it has entered the hashes. -DaveM
1136          *
1137          * Besides that, it does not check for connection
1138          * uniqueness. Wait for troubles.
1139          */
1140         return __sk_prot_rehash(sk);
1141 }
1142 
1143 int inet_sk_rebuild_header(struct sock *sk)
1144 {
1145         struct inet_sock *inet = inet_sk(sk);
1146         struct rtable *rt = (struct rtable *)__sk_dst_check(sk, 0);
1147         __be32 daddr;
1148         struct ip_options_rcu *inet_opt;
1149         struct flowi4 *fl4;
1150         int err;
1151 
1152         /* Route is OK, nothing to do. */
1153         if (rt)
1154                 return 0;
1155 
1156         /* Reroute. */
1157         rcu_read_lock();
1158         inet_opt = rcu_dereference(inet->inet_opt);
1159         daddr = inet->inet_daddr;
1160         if (inet_opt && inet_opt->opt.srr)
1161                 daddr = inet_opt->opt.faddr;
1162         rcu_read_unlock();
1163         fl4 = &inet->cork.fl.u.ip4;
1164         rt = ip_route_output_ports(sock_net(sk), fl4, sk, daddr, inet->inet_saddr,
1165                                    inet->inet_dport, inet->inet_sport,
1166                                    sk->sk_protocol, RT_CONN_FLAGS(sk),
1167                                    sk->sk_bound_dev_if);
1168         if (!IS_ERR(rt)) {
1169                 err = 0;
1170                 sk_setup_caps(sk, &rt->dst);
1171         } else {
1172                 err = PTR_ERR(rt);
1173 
1174                 /* Routing failed... */
1175                 sk->sk_route_caps = 0;
1176                 /*
1177                  * Other protocols have to map its equivalent state to TCP_SYN_SENT.
1178                  * DCCP maps its DCCP_REQUESTING state to TCP_SYN_SENT. -acme
1179                  */
1180                 if (!sock_net(sk)->ipv4.sysctl_ip_dynaddr ||
1181                     sk->sk_state != TCP_SYN_SENT ||
1182                     (sk->sk_userlocks & SOCK_BINDADDR_LOCK) ||
1183                     (err = inet_sk_reselect_saddr(sk)) != 0)
1184                         sk->sk_err_soft = -err;
1185         }
1186 
1187         return err;
1188 }
1189 EXPORT_SYMBOL(inet_sk_rebuild_header);
1190 
1191 struct sk_buff *inet_gso_segment(struct sk_buff *skb,
1192                                  netdev_features_t features)
1193 {
1194         bool udpfrag = false, fixedid = false, gso_partial, encap;
1195         struct sk_buff *segs = ERR_PTR(-EINVAL);
1196         const struct net_offload *ops;
1197         unsigned int offset = 0;
1198         struct iphdr *iph;
1199         int proto, tot_len;
1200         int nhoff;
1201         int ihl;
1202         int id;
1203 
1204         skb_reset_network_header(skb);
1205         nhoff = skb_network_header(skb) - skb_mac_header(skb);
1206         if (unlikely(!pskb_may_pull(skb, sizeof(*iph))))
1207                 goto out;
1208 
1209         iph = ip_hdr(skb);
1210         ihl = iph->ihl * 4;
1211         if (ihl < sizeof(*iph))
1212                 goto out;
1213 
1214         id = ntohs(iph->id);
1215         proto = iph->protocol;
1216 
1217         /* Warning: after this point, iph might be no longer valid */
1218         if (unlikely(!pskb_may_pull(skb, ihl)))
1219                 goto out;
1220         __skb_pull(skb, ihl);
1221 
1222         encap = SKB_GSO_CB(skb)->encap_level > 0;
1223         if (encap)
1224                 features &= skb->dev->hw_enc_features;
1225         SKB_GSO_CB(skb)->encap_level += ihl;
1226 
1227         skb_reset_transport_header(skb);
1228 
1229         segs = ERR_PTR(-EPROTONOSUPPORT);
1230 
1231         if (!skb->encapsulation || encap) {
1232                 udpfrag = !!(skb_shinfo(skb)->gso_type & SKB_GSO_UDP);
1233                 fixedid = !!(skb_shinfo(skb)->gso_type & SKB_GSO_TCP_FIXEDID);
1234 
1235                 /* fixed ID is invalid if DF bit is not set */
1236                 if (fixedid && !(ip_hdr(skb)->frag_off & htons(IP_DF)))
1237                         goto out;
1238         }
1239 
1240         ops = rcu_dereference(inet_offloads[proto]);
1241         if (likely(ops && ops->callbacks.gso_segment))
1242                 segs = ops->callbacks.gso_segment(skb, features);
1243 
1244         if (IS_ERR_OR_NULL(segs))
1245                 goto out;
1246 
1247         gso_partial = !!(skb_shinfo(segs)->gso_type & SKB_GSO_PARTIAL);
1248 
1249         skb = segs;
1250         do {
1251                 iph = (struct iphdr *)(skb_mac_header(skb) + nhoff);
1252                 if (udpfrag) {
1253                         iph->frag_off = htons(offset >> 3);
1254                         if (skb->next)
1255                                 iph->frag_off |= htons(IP_MF);
1256                         offset += skb->len - nhoff - ihl;
1257                         tot_len = skb->len - nhoff;
1258                 } else if (skb_is_gso(skb)) {
1259                         if (!fixedid) {
1260                                 iph->id = htons(id);
1261                                 id += skb_shinfo(skb)->gso_segs;
1262                         }
1263 
1264                         if (gso_partial)
1265                                 tot_len = skb_shinfo(skb)->gso_size +
1266                                           SKB_GSO_CB(skb)->data_offset +
1267                                           skb->head - (unsigned char *)iph;
1268                         else
1269                                 tot_len = skb->len - nhoff;
1270                 } else {
1271                         if (!fixedid)
1272                                 iph->id = htons(id++);
1273                         tot_len = skb->len - nhoff;
1274                 }
1275                 iph->tot_len = htons(tot_len);
1276                 ip_send_check(iph);
1277                 if (encap)
1278                         skb_reset_inner_headers(skb);
1279                 skb->network_header = (u8 *)iph - skb->head;
1280         } while ((skb = skb->next));
1281 
1282 out:
1283         return segs;
1284 }
1285 EXPORT_SYMBOL(inet_gso_segment);
1286 
1287 struct sk_buff **inet_gro_receive(struct sk_buff **head, struct sk_buff *skb)
1288 {
1289         const struct net_offload *ops;
1290         struct sk_buff **pp = NULL;
1291         struct sk_buff *p;
1292         const struct iphdr *iph;
1293         unsigned int hlen;
1294         unsigned int off;
1295         unsigned int id;
1296         int flush = 1;
1297         int proto;
1298 
1299         off = skb_gro_offset(skb);
1300         hlen = off + sizeof(*iph);
1301         iph = skb_gro_header_fast(skb, off);
1302         if (skb_gro_header_hard(skb, hlen)) {
1303                 iph = skb_gro_header_slow(skb, hlen, off);
1304                 if (unlikely(!iph))
1305                         goto out;
1306         }
1307 
1308         proto = iph->protocol;
1309 
1310         rcu_read_lock();
1311         ops = rcu_dereference(inet_offloads[proto]);
1312         if (!ops || !ops->callbacks.gro_receive)
1313                 goto out_unlock;
1314 
1315         if (*(u8 *)iph != 0x45)
1316                 goto out_unlock;
1317 
1318         if (unlikely(ip_fast_csum((u8 *)iph, 5)))
1319                 goto out_unlock;
1320 
1321         id = ntohl(*(__be32 *)&iph->id);
1322         flush = (u16)((ntohl(*(__be32 *)iph) ^ skb_gro_len(skb)) | (id & ~IP_DF));
1323         id >>= 16;
1324 
1325         for (p = *head; p; p = p->next) {
1326                 struct iphdr *iph2;
1327                 u16 flush_id;
1328 
1329                 if (!NAPI_GRO_CB(p)->same_flow)
1330                         continue;
1331 
1332                 iph2 = (struct iphdr *)(p->data + off);
1333                 /* The above works because, with the exception of the top
1334                  * (inner most) layer, we only aggregate pkts with the same
1335                  * hdr length so all the hdrs we'll need to verify will start
1336                  * at the same offset.
1337                  */
1338                 if ((iph->protocol ^ iph2->protocol) |
1339                     ((__force u32)iph->saddr ^ (__force u32)iph2->saddr) |
1340                     ((__force u32)iph->daddr ^ (__force u32)iph2->daddr)) {
1341                         NAPI_GRO_CB(p)->same_flow = 0;
1342                         continue;
1343                 }
1344 
1345                 /* All fields must match except length and checksum. */
1346                 NAPI_GRO_CB(p)->flush |=
1347                         (iph->ttl ^ iph2->ttl) |
1348                         (iph->tos ^ iph2->tos) |
1349                         ((iph->frag_off ^ iph2->frag_off) & htons(IP_DF));
1350 
1351                 NAPI_GRO_CB(p)->flush |= flush;
1352 
1353                 /* We need to store of the IP ID check to be included later
1354                  * when we can verify that this packet does in fact belong
1355                  * to a given flow.
1356                  */
1357                 flush_id = (u16)(id - ntohs(iph2->id));
1358 
1359                 /* This bit of code makes it much easier for us to identify
1360                  * the cases where we are doing atomic vs non-atomic IP ID
1361                  * checks.  Specifically an atomic check can return IP ID
1362                  * values 0 - 0xFFFF, while a non-atomic check can only
1363                  * return 0 or 0xFFFF.
1364                  */
1365                 if (!NAPI_GRO_CB(p)->is_atomic ||
1366                     !(iph->frag_off & htons(IP_DF))) {
1367                         flush_id ^= NAPI_GRO_CB(p)->count;
1368                         flush_id = flush_id ? 0xFFFF : 0;
1369                 }
1370 
1371                 /* If the previous IP ID value was based on an atomic
1372                  * datagram we can overwrite the value and ignore it.
1373                  */
1374                 if (NAPI_GRO_CB(skb)->is_atomic)
1375                         NAPI_GRO_CB(p)->flush_id = flush_id;
1376                 else
1377                         NAPI_GRO_CB(p)->flush_id |= flush_id;
1378         }
1379 
1380         NAPI_GRO_CB(skb)->is_atomic = !!(iph->frag_off & htons(IP_DF));
1381         NAPI_GRO_CB(skb)->flush |= flush;
1382         skb_set_network_header(skb, off);
1383         /* The above will be needed by the transport layer if there is one
1384          * immediately following this IP hdr.
1385          */
1386 
1387         /* Note : No need to call skb_gro_postpull_rcsum() here,
1388          * as we already checked checksum over ipv4 header was 0
1389          */
1390         skb_gro_pull(skb, sizeof(*iph));
1391         skb_set_transport_header(skb, skb_gro_offset(skb));
1392 
1393         pp = call_gro_receive(ops->callbacks.gro_receive, head, skb);
1394 
1395 out_unlock:
1396         rcu_read_unlock();
1397 
1398 out:
1399         NAPI_GRO_CB(skb)->flush |= flush;
1400 
1401         return pp;
1402 }
1403 EXPORT_SYMBOL(inet_gro_receive);
1404 
1405 static struct sk_buff **ipip_gro_receive(struct sk_buff **head,
1406                                          struct sk_buff *skb)
1407 {
1408         if (NAPI_GRO_CB(skb)->encap_mark) {
1409                 NAPI_GRO_CB(skb)->flush = 1;
1410                 return NULL;
1411         }
1412 
1413         NAPI_GRO_CB(skb)->encap_mark = 1;
1414 
1415         return inet_gro_receive(head, skb);
1416 }
1417 
1418 #define SECONDS_PER_DAY 86400
1419 
1420 /* inet_current_timestamp - Return IP network timestamp
1421  *
1422  * Return milliseconds since midnight in network byte order.
1423  */
1424 __be32 inet_current_timestamp(void)
1425 {
1426         u32 secs;
1427         u32 msecs;
1428         struct timespec64 ts;
1429 
1430         ktime_get_real_ts64(&ts);
1431 
1432         /* Get secs since midnight. */
1433         (void)div_u64_rem(ts.tv_sec, SECONDS_PER_DAY, &secs);
1434         /* Convert to msecs. */
1435         msecs = secs * MSEC_PER_SEC;
1436         /* Convert nsec to msec. */
1437         msecs += (u32)ts.tv_nsec / NSEC_PER_MSEC;
1438 
1439         /* Convert to network byte order. */
1440         return htonl(msecs);
1441 }
1442 EXPORT_SYMBOL(inet_current_timestamp);
1443 
1444 int inet_recv_error(struct sock *sk, struct msghdr *msg, int len, int *addr_len)
1445 {
1446         if (sk->sk_family == AF_INET)
1447                 return ip_recv_error(sk, msg, len, addr_len);
1448 #if IS_ENABLED(CONFIG_IPV6)
1449         if (sk->sk_family == AF_INET6)
1450                 return pingv6_ops.ipv6_recv_error(sk, msg, len, addr_len);
1451 #endif
1452         return -EINVAL;
1453 }
1454 
1455 int inet_gro_complete(struct sk_buff *skb, int nhoff)
1456 {
1457         __be16 newlen = htons(skb->len - nhoff);
1458         struct iphdr *iph = (struct iphdr *)(skb->data + nhoff);
1459         const struct net_offload *ops;
1460         int proto = iph->protocol;
1461         int err = -ENOSYS;
1462 
1463         if (skb->encapsulation)
1464                 skb_set_inner_network_header(skb, nhoff);
1465 
1466         csum_replace2(&iph->check, iph->tot_len, newlen);
1467         iph->tot_len = newlen;
1468 
1469         rcu_read_lock();
1470         ops = rcu_dereference(inet_offloads[proto]);
1471         if (WARN_ON(!ops || !ops->callbacks.gro_complete))
1472                 goto out_unlock;
1473 
1474         /* Only need to add sizeof(*iph) to get to the next hdr below
1475          * because any hdr with option will have been flushed in
1476          * inet_gro_receive().
1477          */
1478         err = ops->callbacks.gro_complete(skb, nhoff + sizeof(*iph));
1479 
1480 out_unlock:
1481         rcu_read_unlock();
1482 
1483         return err;
1484 }
1485 EXPORT_SYMBOL(inet_gro_complete);
1486 
1487 static int ipip_gro_complete(struct sk_buff *skb, int nhoff)
1488 {
1489         skb->encapsulation = 1;
1490         skb_shinfo(skb)->gso_type |= SKB_GSO_IPXIP4;
1491         return inet_gro_complete(skb, nhoff);
1492 }
1493 
1494 int inet_ctl_sock_create(struct sock **sk, unsigned short family,
1495                          unsigned short type, unsigned char protocol,
1496                          struct net *net)
1497 {
1498         struct socket *sock;
1499         int rc = sock_create_kern(net, family, type, protocol, &sock);
1500 
1501         if (rc == 0) {
1502                 *sk = sock->sk;
1503                 (*sk)->sk_allocation = GFP_ATOMIC;
1504                 /*
1505                  * Unhash it so that IP input processing does not even see it,
1506                  * we do not wish this socket to see incoming packets.
1507                  */
1508                 (*sk)->sk_prot->unhash(*sk);
1509         }
1510         return rc;
1511 }
1512 EXPORT_SYMBOL_GPL(inet_ctl_sock_create);
1513 
1514 u64 snmp_get_cpu_field(void __percpu *mib, int cpu, int offt)
1515 {
1516         return  *(((unsigned long *)per_cpu_ptr(mib, cpu)) + offt);
1517 }
1518 EXPORT_SYMBOL_GPL(snmp_get_cpu_field);
1519 
1520 unsigned long snmp_fold_field(void __percpu *mib, int offt)
1521 {
1522         unsigned long res = 0;
1523         int i;
1524 
1525         for_each_possible_cpu(i)
1526                 res += snmp_get_cpu_field(mib, i, offt);
1527         return res;
1528 }
1529 EXPORT_SYMBOL_GPL(snmp_fold_field);
1530 
1531 #if BITS_PER_LONG==32
1532 
1533 u64 snmp_get_cpu_field64(void __percpu *mib, int cpu, int offt,
1534                          size_t syncp_offset)
1535 {
1536         void *bhptr;
1537         struct u64_stats_sync *syncp;
1538         u64 v;
1539         unsigned int start;
1540 
1541         bhptr = per_cpu_ptr(mib, cpu);
1542         syncp = (struct u64_stats_sync *)(bhptr + syncp_offset);
1543         do {
1544                 start = u64_stats_fetch_begin_irq(syncp);
1545                 v = *(((u64 *)bhptr) + offt);
1546         } while (u64_stats_fetch_retry_irq(syncp, start));
1547 
1548         return v;
1549 }
1550 EXPORT_SYMBOL_GPL(snmp_get_cpu_field64);
1551 
1552 u64 snmp_fold_field64(void __percpu *mib, int offt, size_t syncp_offset)
1553 {
1554         u64 res = 0;
1555         int cpu;
1556 
1557         for_each_possible_cpu(cpu) {
1558                 res += snmp_get_cpu_field64(mib, cpu, offt, syncp_offset);
1559         }
1560         return res;
1561 }
1562 EXPORT_SYMBOL_GPL(snmp_fold_field64);
1563 #endif
1564 
1565 #ifdef CONFIG_IP_MULTICAST
1566 static const struct net_protocol igmp_protocol = {
1567         .handler =      igmp_rcv,
1568         .netns_ok =     1,
1569 };
1570 #endif
1571 
1572 static const struct net_protocol tcp_protocol = {
1573         .early_demux    =       tcp_v4_early_demux,
1574         .handler        =       tcp_v4_rcv,
1575         .err_handler    =       tcp_v4_err,
1576         .no_policy      =       1,
1577         .netns_ok       =       1,
1578         .icmp_strict_tag_validation = 1,
1579 };
1580 
1581 static const struct net_protocol udp_protocol = {
1582         .early_demux =  udp_v4_early_demux,
1583         .handler =      udp_rcv,
1584         .err_handler =  udp_err,
1585         .no_policy =    1,
1586         .netns_ok =     1,
1587 };
1588 
1589 static const struct net_protocol icmp_protocol = {
1590         .handler =      icmp_rcv,
1591         .err_handler =  icmp_err,
1592         .no_policy =    1,
1593         .netns_ok =     1,
1594 };
1595 
1596 static __net_init int ipv4_mib_init_net(struct net *net)
1597 {
1598         int i;
1599 
1600         net->mib.tcp_statistics = alloc_percpu(struct tcp_mib);
1601         if (!net->mib.tcp_statistics)
1602                 goto err_tcp_mib;
1603         net->mib.ip_statistics = alloc_percpu(struct ipstats_mib);
1604         if (!net->mib.ip_statistics)
1605                 goto err_ip_mib;
1606 
1607         for_each_possible_cpu(i) {
1608                 struct ipstats_mib *af_inet_stats;
1609                 af_inet_stats = per_cpu_ptr(net->mib.ip_statistics, i);
1610                 u64_stats_init(&af_inet_stats->syncp);
1611         }
1612 
1613         net->mib.net_statistics = alloc_percpu(struct linux_mib);
1614         if (!net->mib.net_statistics)
1615                 goto err_net_mib;
1616         net->mib.udp_statistics = alloc_percpu(struct udp_mib);
1617         if (!net->mib.udp_statistics)
1618                 goto err_udp_mib;
1619         net->mib.udplite_statistics = alloc_percpu(struct udp_mib);
1620         if (!net->mib.udplite_statistics)
1621                 goto err_udplite_mib;
1622         net->mib.icmp_statistics = alloc_percpu(struct icmp_mib);
1623         if (!net->mib.icmp_statistics)
1624                 goto err_icmp_mib;
1625         net->mib.icmpmsg_statistics = kzalloc(sizeof(struct icmpmsg_mib),
1626                                               GFP_KERNEL);
1627         if (!net->mib.icmpmsg_statistics)
1628                 goto err_icmpmsg_mib;
1629 
1630         tcp_mib_init(net);
1631         return 0;
1632 
1633 err_icmpmsg_mib:
1634         free_percpu(net->mib.icmp_statistics);
1635 err_icmp_mib:
1636         free_percpu(net->mib.udplite_statistics);
1637 err_udplite_mib:
1638         free_percpu(net->mib.udp_statistics);
1639 err_udp_mib:
1640         free_percpu(net->mib.net_statistics);
1641 err_net_mib:
1642         free_percpu(net->mib.ip_statistics);
1643 err_ip_mib:
1644         free_percpu(net->mib.tcp_statistics);
1645 err_tcp_mib:
1646         return -ENOMEM;
1647 }
1648 
1649 static __net_exit void ipv4_mib_exit_net(struct net *net)
1650 {
1651         kfree(net->mib.icmpmsg_statistics);
1652         free_percpu(net->mib.icmp_statistics);
1653         free_percpu(net->mib.udplite_statistics);
1654         free_percpu(net->mib.udp_statistics);
1655         free_percpu(net->mib.net_statistics);
1656         free_percpu(net->mib.ip_statistics);
1657         free_percpu(net->mib.tcp_statistics);
1658 }
1659 
1660 static __net_initdata struct pernet_operations ipv4_mib_ops = {
1661         .init = ipv4_mib_init_net,
1662         .exit = ipv4_mib_exit_net,
1663 };
1664 
1665 static int __init init_ipv4_mibs(void)
1666 {
1667         return register_pernet_subsys(&ipv4_mib_ops);
1668 }
1669 
1670 static __net_init int inet_init_net(struct net *net)
1671 {
1672         /*
1673          * Set defaults for local port range
1674          */
1675         seqlock_init(&net->ipv4.ip_local_ports.lock);
1676         net->ipv4.ip_local_ports.range[0] =  32768;
1677         net->ipv4.ip_local_ports.range[1] =  60999;
1678 
1679         seqlock_init(&net->ipv4.ping_group_range.lock);
1680         /*
1681          * Sane defaults - nobody may create ping sockets.
1682          * Boot scripts should set this to distro-specific group.
1683          */
1684         net->ipv4.ping_group_range.range[0] = make_kgid(&init_user_ns, 1);
1685         net->ipv4.ping_group_range.range[1] = make_kgid(&init_user_ns, 0);
1686 
1687         /* Default values for sysctl-controlled parameters.
1688          * We set them here, in case sysctl is not compiled.
1689          */
1690         net->ipv4.sysctl_ip_default_ttl = IPDEFTTL;
1691         net->ipv4.sysctl_ip_dynaddr = 0;
1692         net->ipv4.sysctl_ip_early_demux = 1;
1693 
1694         return 0;
1695 }
1696 
1697 static __net_exit void inet_exit_net(struct net *net)
1698 {
1699 }
1700 
1701 static __net_initdata struct pernet_operations af_inet_ops = {
1702         .init = inet_init_net,
1703         .exit = inet_exit_net,
1704 };
1705 
1706 static int __init init_inet_pernet_ops(void)
1707 {
1708         return register_pernet_subsys(&af_inet_ops);
1709 }
1710 
1711 static int ipv4_proc_init(void);
1712 
1713 /*
1714  *      IP protocol layer initialiser
1715  */
1716 
1717 static struct packet_offload ip_packet_offload __read_mostly = {
1718         .type = cpu_to_be16(ETH_P_IP),
1719         .callbacks = {
1720                 .gso_segment = inet_gso_segment,
1721                 .gro_receive = inet_gro_receive,
1722                 .gro_complete = inet_gro_complete,
1723         },
1724 };
1725 
1726 static const struct net_offload ipip_offload = {
1727         .callbacks = {
1728                 .gso_segment    = inet_gso_segment,
1729                 .gro_receive    = ipip_gro_receive,
1730                 .gro_complete   = ipip_gro_complete,
1731         },
1732 };
1733 
1734 static int __init ipv4_offload_init(void)
1735 {
1736         /*
1737          * Add offloads
1738          */
1739         if (udpv4_offload_init() < 0)
1740                 pr_crit("%s: Cannot add UDP protocol offload\n", __func__);
1741         if (tcpv4_offload_init() < 0)
1742                 pr_crit("%s: Cannot add TCP protocol offload\n", __func__);
1743 
1744         dev_add_offload(&ip_packet_offload);
1745         inet_add_offload(&ipip_offload, IPPROTO_IPIP);
1746         return 0;
1747 }
1748 
1749 fs_initcall(ipv4_offload_init);
1750 
1751 static struct packet_type ip_packet_type __read_mostly = {
1752         .type = cpu_to_be16(ETH_P_IP),
1753         .func = ip_rcv,
1754 };
1755 
1756 static int __init inet_init(void)
1757 {
1758         struct inet_protosw *q;
1759         struct list_head *r;
1760         int rc = -EINVAL;
1761 
1762         sock_skb_cb_check_size(sizeof(struct inet_skb_parm));
1763 
1764         rc = proto_register(&tcp_prot, 1);
1765         if (rc)
1766                 goto out;
1767 
1768         rc = proto_register(&udp_prot, 1);
1769         if (rc)
1770                 goto out_unregister_tcp_proto;
1771 
1772         rc = proto_register(&raw_prot, 1);
1773         if (rc)
1774                 goto out_unregister_udp_proto;
1775 
1776         rc = proto_register(&ping_prot, 1);
1777         if (rc)
1778                 goto out_unregister_raw_proto;
1779 
1780         /*
1781          *      Tell SOCKET that we are alive...
1782          */
1783 
1784         (void)sock_register(&inet_family_ops);
1785 
1786 #ifdef CONFIG_SYSCTL
1787         ip_static_sysctl_init();
1788 #endif
1789 
1790         /*
1791          *      Add all the base protocols.
1792          */
1793 
1794         if (inet_add_protocol(&icmp_protocol, IPPROTO_ICMP) < 0)
1795                 pr_crit("%s: Cannot add ICMP protocol\n", __func__);
1796         if (inet_add_protocol(&udp_protocol, IPPROTO_UDP) < 0)
1797                 pr_crit("%s: Cannot add UDP protocol\n", __func__);
1798         if (inet_add_protocol(&tcp_protocol, IPPROTO_TCP) < 0)
1799                 pr_crit("%s: Cannot add TCP protocol\n", __func__);
1800 #ifdef CONFIG_IP_MULTICAST
1801         if (inet_add_protocol(&igmp_protocol, IPPROTO_IGMP) < 0)
1802                 pr_crit("%s: Cannot add IGMP protocol\n", __func__);
1803 #endif
1804 
1805         /* Register the socket-side information for inet_create. */
1806         for (r = &inetsw[0]; r < &inetsw[SOCK_MAX]; ++r)
1807                 INIT_LIST_HEAD(r);
1808 
1809         for (q = inetsw_array; q < &inetsw_array[INETSW_ARRAY_LEN]; ++q)
1810                 inet_register_protosw(q);
1811 
1812         /*
1813          *      Set the ARP module up
1814          */
1815 
1816         arp_init();
1817 
1818         /*
1819          *      Set the IP module up
1820          */
1821 
1822         ip_init();
1823 
1824         tcp_v4_init();
1825 
1826         /* Setup TCP slab cache for open requests. */
1827         tcp_init();
1828 
1829         /* Setup UDP memory threshold */
1830         udp_init();
1831 
1832         /* Add UDP-Lite (RFC 3828) */
1833         udplite4_register();
1834 
1835         ping_init();
1836 
1837         /*
1838          *      Set the ICMP layer up
1839          */
1840 
1841         if (icmp_init() < 0)
1842                 panic("Failed to create the ICMP control socket.\n");
1843 
1844         /*
1845          *      Initialise the multicast router
1846          */
1847 #if defined(CONFIG_IP_MROUTE)
1848         if (ip_mr_init())
1849                 pr_crit("%s: Cannot init ipv4 mroute\n", __func__);
1850 #endif
1851 
1852         if (init_inet_pernet_ops())
1853                 pr_crit("%s: Cannot init ipv4 inet pernet ops\n", __func__);
1854         /*
1855          *      Initialise per-cpu ipv4 mibs
1856          */
1857 
1858         if (init_ipv4_mibs())
1859                 pr_crit("%s: Cannot init ipv4 mibs\n", __func__);
1860 
1861         ipv4_proc_init();
1862 
1863         ipfrag_init();
1864 
1865         dev_add_pack(&ip_packet_type);
1866 
1867         ip_tunnel_core_init();
1868 
1869         rc = 0;
1870 out:
1871         return rc;
1872 out_unregister_raw_proto:
1873         proto_unregister(&raw_prot);
1874 out_unregister_udp_proto:
1875         proto_unregister(&udp_prot);
1876 out_unregister_tcp_proto:
1877         proto_unregister(&tcp_prot);
1878         goto out;
1879 }
1880 
1881 fs_initcall(inet_init);
1882 
1883 /* ------------------------------------------------------------------------ */
1884 
1885 #ifdef CONFIG_PROC_FS
1886 static int __init ipv4_proc_init(void)
1887 {
1888         int rc = 0;
1889 
1890         if (raw_proc_init())
1891                 goto out_raw;
1892         if (tcp4_proc_init())
1893                 goto out_tcp;
1894         if (udp4_proc_init())
1895                 goto out_udp;
1896         if (ping_proc_init())
1897                 goto out_ping;
1898         if (ip_misc_proc_init())
1899                 goto out_misc;
1900 out:
1901         return rc;
1902 out_misc:
1903         ping_proc_exit();
1904 out_ping:
1905         udp4_proc_exit();
1906 out_udp:
1907         tcp4_proc_exit();
1908 out_tcp:
1909         raw_proc_exit();
1910 out_raw:
1911         rc = -ENOMEM;
1912         goto out;
1913 }
1914 
1915 #else /* CONFIG_PROC_FS */
1916 static int __init ipv4_proc_init(void)
1917 {
1918         return 0;
1919 }
1920 #endif /* CONFIG_PROC_FS */
1921 

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