net/rxrpc/ar-accept.c

   1 /* incoming call handling
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/net.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/errqueue.h>
  16 #include <linux/udp.h>
  17 #include <linux/in.h>
  18 #include <linux/in6.h>
  19 #include <linux/icmp.h>
  20 #include <net/sock.h>
  21 #include <net/af_rxrpc.h>
  22 #include <net/ip.h>
  23 #include "ar-internal.h"
  24
  25 /*
  26  * generate a connection-level abort
  27  */
  28 static int rxrpc_busy(struct rxrpc_local *local, struct sockaddr_rxrpc *srx,
  29                       struct rxrpc_header *hdr)
  30 {
  31         struct msghdr msg;
  32         struct kvec iov[1];
  33         size_t len;
  34         int ret;
  35
  36         _enter("%d,,", local->debug_id);
  37
  38         msg.msg_name    = &srx->transport.sin;
  39         msg.msg_namelen = sizeof(srx->transport.sin);
  40         msg.msg_control = NULL;
  41         msg.msg_controllen = 0;
  42         msg.msg_flags   = 0;
  43
  44         hdr->seq        = 0;
  45         hdr->type       = RXRPC_PACKET_TYPE_BUSY;
  46         hdr->flags      = 0;
  47         hdr->userStatus = 0;
  48         hdr->_rsvd      = 0;
  49
  50         iov[0].iov_base = hdr;
  51         iov[0].iov_len  = sizeof(*hdr);
  52
  53         len = iov[0].iov_len;
  54
  55         hdr->serial = htonl(1);
  56         _proto("Tx BUSY %%%u", ntohl(hdr->serial));
  57
  58         ret = kernel_sendmsg(local->socket, &msg, iov, 1, len);
  59         if (ret < 0) {
  60                 _leave(" = -EAGAIN [sendmsg failed: %d]", ret);
  61                 return -EAGAIN;
  62         }
  63
  64         _leave(" = 0");
  65         return 0;
  66 }
  67
  68 /*
  69  * accept an incoming call that needs peer, transport and/or connection setting
  70  * up
  71  */
  72 static int rxrpc_accept_incoming_call(struct rxrpc_local *local,
  73                                       struct rxrpc_sock *rx,
  74                                       struct sk_buff *skb,
  75                                       struct sockaddr_rxrpc *srx)
  76 {
  77         struct rxrpc_connection *conn;
  78         struct rxrpc_transport *trans;
  79         struct rxrpc_skb_priv *sp, *nsp;
  80         struct rxrpc_peer *peer;
  81         struct rxrpc_call *call;
  82         struct sk_buff *notification;
  83         int ret;
  84
  85         _enter("");
  86
  87         sp = rxrpc_skb(skb);
  88
  89         /* get a notification message to send to the server app */
  90         notification = alloc_skb(0, GFP_NOFS);
  91         rxrpc_new_skb(notification);
  92         notification->mark = RXRPC_SKB_MARK_NEW_CALL;
  93
  94         peer = rxrpc_get_peer(srx, GFP_NOIO);
  95         if (IS_ERR(peer)) {
  96                 _debug("no peer");
  97                 ret = -EBUSY;
  98                 goto error;
  99         }
 100
 101         trans = rxrpc_get_transport(local, peer, GFP_NOIO);
 102         rxrpc_put_peer(peer);
 103         if (!trans) {
 104                 _debug("no trans");
 105                 ret = -EBUSY;
 106                 goto error;
 107         }
 108
 109         conn = rxrpc_incoming_connection(trans, &sp->hdr, GFP_NOIO);
 110         rxrpc_put_transport(trans);
 111         if (IS_ERR(conn)) {
 112                 _debug("no conn");
 113                 ret = PTR_ERR(conn);
 114                 goto error;
 115         }
 116
 117         call = rxrpc_incoming_call(rx, conn, &sp->hdr, GFP_NOIO);
 118         rxrpc_put_connection(conn);
 119         if (IS_ERR(call)) {
 120                 _debug("no call");
 121                 ret = PTR_ERR(call);
 122                 goto error;
 123         }
 124
 125         /* attach the call to the socket */
 126         read_lock_bh(&local->services_lock);
 127         if (rx->sk.sk_state == RXRPC_CLOSE)
 128                 goto invalid_service;
 129
 130         write_lock(&rx->call_lock);
 131         if (!test_and_set_bit(RXRPC_CALL_INIT_ACCEPT, &call->flags)) {
 132                 rxrpc_get_call(call);
 133
 134                 spin_lock(&call->conn->state_lock);
 135                 if (sp->hdr.securityIndex > 0 &&
 136                     call->conn->state == RXRPC_CONN_SERVER_UNSECURED) {
 137                         _debug("await conn sec");
 138                         list_add_tail(&call->accept_link, &rx->secureq);
 139                         call->conn->state = RXRPC_CONN_SERVER_CHALLENGING;
 140                         atomic_inc(&call->conn->usage);
 141                         set_bit(RXRPC_CONN_CHALLENGE, &call->conn->events);
 142                         rxrpc_queue_conn(call->conn);
 143                 } else {
 144                         _debug("conn ready");
 145                         call->state = RXRPC_CALL_SERVER_ACCEPTING;
 146                         list_add_tail(&call->accept_link, &rx->acceptq);
 147                         rxrpc_get_call(call);
 148                         nsp = rxrpc_skb(notification);
 149                         nsp->call = call;
 150
 151                         ASSERTCMP(atomic_read(&call->usage), >=, 3);
 152
 153                         _debug("notify");
 154                         spin_lock(&call->lock);
 155                         ret = rxrpc_queue_rcv_skb(call, notification, true,
 156                                                   false);
 157                         spin_unlock(&call->lock);
 158                         notification = NULL;
 159 <<<<<<< HEAD:net/rxrpc/ar-accept.c
 160                         if (ret < 0)
 161                                 BUG();
 162 =======
 163                         BUG_ON(ret < 0);
 164 >>>>>>> 264e3e889d86e552b4191d69bb60f4f3b383135a:net/rxrpc/ar-accept.c
 165                 }
 166                 spin_unlock(&call->conn->state_lock);
 167
 168                 _debug("queued");
 169         }
 170         write_unlock(&rx->call_lock);
 171
 172         _debug("process");
 173         rxrpc_fast_process_packet(call, skb);
 174
 175         _debug("done");
 176         read_unlock_bh(&local->services_lock);
 177         rxrpc_free_skb(notification);
 178         rxrpc_put_call(call);
 179         _leave(" = 0");
 180         return 0;
 181
 182 invalid_service:
 183         _debug("invalid");
 184         read_unlock_bh(&local->services_lock);
 185
 186         read_lock_bh(&call->state_lock);
 187         if (!test_bit(RXRPC_CALL_RELEASE, &call->flags) &&
 188             !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events)) {
 189                 rxrpc_get_call(call);
 190                 rxrpc_queue_call(call);
 191         }
 192         read_unlock_bh(&call->state_lock);
 193         rxrpc_put_call(call);
 194         ret = -ECONNREFUSED;
 195 error:
 196         rxrpc_free_skb(notification);
 197         _leave(" = %d", ret);
 198         return ret;
 199 }
 200
 201 /*
 202  * accept incoming calls that need peer, transport and/or connection setting up
 203  * - the packets we get are all incoming client DATA packets that have seq == 1
 204  */
 205 void rxrpc_accept_incoming_calls(struct work_struct *work)
 206 {
 207         struct rxrpc_local *local =
 208                 container_of(work, struct rxrpc_local, acceptor);
 209         struct rxrpc_skb_priv *sp;
 210         struct sockaddr_rxrpc srx;
 211         struct rxrpc_sock *rx;
 212         struct sk_buff *skb;
 213         __be16 service_id;
 214         int ret;
 215
 216         _enter("%d", local->debug_id);
 217
 218         read_lock_bh(&rxrpc_local_lock);
 219         if (atomic_read(&local->usage) > 0)
 220                 rxrpc_get_local(local);
 221         else
 222                 local = NULL;
 223         read_unlock_bh(&rxrpc_local_lock);
 224         if (!local) {
 225                 _leave(" [local dead]");
 226                 return;
 227         }
 228
 229 process_next_packet:
 230         skb = skb_dequeue(&local->accept_queue);
 231         if (!skb) {
 232                 rxrpc_put_local(local);
 233                 _leave("\n");
 234                 return;
 235         }
 236
 237         _net("incoming call skb %p", skb);
 238
 239         sp = rxrpc_skb(skb);
 240
 241         /* determine the remote address */
 242         memset(&srx, 0, sizeof(srx));
 243         srx.srx_family = AF_RXRPC;
 244         srx.transport.family = local->srx.transport.family;
 245         srx.transport_type = local->srx.transport_type;
 246         switch (srx.transport.family) {
 247         case AF_INET:
 248                 srx.transport_len = sizeof(struct sockaddr_in);
 249                 srx.transport.sin.sin_port = udp_hdr(skb)->source;
 250                 srx.transport.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
 251                 break;
 252         default:
 253                 goto busy;
 254         }
 255
 256         /* get the socket providing the service */
 257         service_id = sp->hdr.serviceId;
 258         read_lock_bh(&local->services_lock);
 259         list_for_each_entry(rx, &local->services, listen_link) {
 260                 if (rx->service_id == service_id &&
 261                     rx->sk.sk_state != RXRPC_CLOSE)
 262                         goto found_service;
 263         }
 264         read_unlock_bh(&local->services_lock);
 265         goto invalid_service;
 266
 267 found_service:
 268         _debug("found service %hd", ntohs(rx->service_id));
 269         if (sk_acceptq_is_full(&rx->sk))
 270                 goto backlog_full;
 271         sk_acceptq_added(&rx->sk);
 272         sock_hold(&rx->sk);
 273         read_unlock_bh(&local->services_lock);
 274
 275         ret = rxrpc_accept_incoming_call(local, rx, skb, &srx);
 276         if (ret < 0)
 277                 sk_acceptq_removed(&rx->sk);
 278         sock_put(&rx->sk);
 279         switch (ret) {
 280         case -ECONNRESET: /* old calls are ignored */
 281         case -ECONNABORTED: /* aborted calls are reaborted or ignored */
 282         case 0:
 283                 goto process_next_packet;
 284         case -ECONNREFUSED:
 285                 goto invalid_service;
 286         case -EBUSY:
 287                 goto busy;
 288         case -EKEYREJECTED:
 289                 goto security_mismatch;
 290         default:
 291                 BUG();
 292         }
 293
 294 backlog_full:
 295         read_unlock_bh(&local->services_lock);
 296 busy:
 297         rxrpc_busy(local, &srx, &sp->hdr);
 298         rxrpc_free_skb(skb);
 299         goto process_next_packet;
 300
 301 invalid_service:
 302         skb->priority = RX_INVALID_OPERATION;
 303         rxrpc_reject_packet(local, skb);
 304         goto process_next_packet;
 305
 306         /* can't change connection security type mid-flow */
 307 security_mismatch:
 308         skb->priority = RX_PROTOCOL_ERROR;
 309         rxrpc_reject_packet(local, skb);
 310         goto process_next_packet;
 311 }
 312
 313 /*
 314  * handle acceptance of a call by userspace
 315  * - assign the user call ID to the call at the front of the queue
 316  */
 317 struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
 318                                      unsigned long user_call_ID)
 319 {
 320         struct rxrpc_call *call;
 321         struct rb_node *parent, **pp;
 322         int ret;
 323
 324         _enter(",%lx", user_call_ID);
 325
 326         ASSERT(!irqs_disabled());
 327
 328         write_lock(&rx->call_lock);
 329
 330         ret = -ENODATA;
 331         if (list_empty(&rx->acceptq))
 332                 goto out;
 333
 334         /* check the user ID isn't already in use */
 335         ret = -EBADSLT;
 336         pp = &rx->calls.rb_node;
 337         parent = NULL;
 338         while (*pp) {
 339                 parent = *pp;
 340                 call = rb_entry(parent, struct rxrpc_call, sock_node);
 341
 342                 if (user_call_ID < call->user_call_ID)
 343                         pp = &(*pp)->rb_left;
 344                 else if (user_call_ID > call->user_call_ID)
 345                         pp = &(*pp)->rb_right;
 346                 else
 347                         goto out;
 348         }
 349
 350         /* dequeue the first call and check it's still valid */
 351         call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
 352         list_del_init(&call->accept_link);
 353         sk_acceptq_removed(&rx->sk);
 354
 355         write_lock_bh(&call->state_lock);
 356         switch (call->state) {
 357         case RXRPC_CALL_SERVER_ACCEPTING:
 358                 call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
 359                 break;
 360         case RXRPC_CALL_REMOTELY_ABORTED:
 361         case RXRPC_CALL_LOCALLY_ABORTED:
 362                 ret = -ECONNABORTED;
 363                 goto out_release;
 364         case RXRPC_CALL_NETWORK_ERROR:
 365                 ret = call->conn->error;
 366                 goto out_release;
 367         case RXRPC_CALL_DEAD:
 368                 ret = -ETIME;
 369                 goto out_discard;
 370         default:
 371                 BUG();
 372         }
 373
 374         /* formalise the acceptance */
 375         call->user_call_ID = user_call_ID;
 376         rb_link_node(&call->sock_node, parent, pp);
 377         rb_insert_color(&call->sock_node, &rx->calls);
 378         if (test_and_set_bit(RXRPC_CALL_HAS_USERID, &call->flags))
 379                 BUG();
 380         if (test_and_set_bit(RXRPC_CALL_ACCEPTED, &call->events))
 381                 BUG();
 382         rxrpc_queue_call(call);
 383
 384         rxrpc_get_call(call);
 385         write_unlock_bh(&call->state_lock);
 386         write_unlock(&rx->call_lock);
 387         _leave(" = %p{%d}", call, call->debug_id);
 388         return call;
 389
 390         /* if the call is already dying or dead, then we leave the socket's ref
 391          * on it to be released by rxrpc_dead_call_expired() as induced by
 392          * rxrpc_release_call() */
 393 out_release:
 394         _debug("release %p", call);
 395         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
 396             !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
 397                 rxrpc_queue_call(call);
 398 out_discard:
 399         write_unlock_bh(&call->state_lock);
 400         _debug("discard %p", call);
 401 out:
 402         write_unlock(&rx->call_lock);
 403         _leave(" = %d", ret);
 404         return ERR_PTR(ret);
 405 }
 406
 407 /*
 408  * handle rejectance of a call by userspace
 409  * - reject the call at the front of the queue
 410  */
 411 int rxrpc_reject_call(struct rxrpc_sock *rx)
 412 {
 413         struct rxrpc_call *call;
 414         int ret;
 415
 416         _enter("");
 417
 418         ASSERT(!irqs_disabled());
 419
 420         write_lock(&rx->call_lock);
 421
 422         ret = -ENODATA;
 423         if (list_empty(&rx->acceptq))
 424                 goto out;
 425
 426         /* dequeue the first call and check it's still valid */
 427         call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
 428         list_del_init(&call->accept_link);
 429         sk_acceptq_removed(&rx->sk);
 430
 431         write_lock_bh(&call->state_lock);
 432         switch (call->state) {
 433         case RXRPC_CALL_SERVER_ACCEPTING:
 434                 call->state = RXRPC_CALL_SERVER_BUSY;
 435                 if (test_and_set_bit(RXRPC_CALL_REJECT_BUSY, &call->events))
 436                         rxrpc_queue_call(call);
 437                 ret = 0;
 438                 goto out_release;
 439         case RXRPC_CALL_REMOTELY_ABORTED:
 440         case RXRPC_CALL_LOCALLY_ABORTED:
 441                 ret = -ECONNABORTED;
 442                 goto out_release;
 443         case RXRPC_CALL_NETWORK_ERROR:
 444                 ret = call->conn->error;
 445                 goto out_release;
 446         case RXRPC_CALL_DEAD:
 447                 ret = -ETIME;
 448                 goto out_discard;
 449         default:
 450                 BUG();
 451         }
 452
 453         /* if the call is already dying or dead, then we leave the socket's ref
 454          * on it to be released by rxrpc_dead_call_expired() as induced by
 455          * rxrpc_release_call() */
 456 out_release:
 457         _debug("release %p", call);
 458         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
 459             !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
 460                 rxrpc_queue_call(call);
 461 out_discard:
 462         write_unlock_bh(&call->state_lock);
 463         _debug("discard %p", call);
 464 out:
 465         write_unlock(&rx->call_lock);
 466         _leave(" = %d", ret);
 467         return ret;
 468 }
 469
 470 /**
 471  * rxrpc_kernel_accept_call - Allow a kernel service to accept an incoming call
 472  * @sock: The socket on which the impending call is waiting
 473  * @user_call_ID: The tag to attach to the call
 474  *
 475  * Allow a kernel service to accept an incoming call, assuming the incoming
 476  * call is still valid.
 477  */
 478 struct rxrpc_call *rxrpc_kernel_accept_call(struct socket *sock,
 479                                             unsigned long user_call_ID)
 480 {
 481         struct rxrpc_call *call;
 482
 483         _enter(",%lx", user_call_ID);
 484         call = rxrpc_accept_call(rxrpc_sk(sock->sk), user_call_ID);
 485         _leave(" = %p", call);
 486         return call;
 487 }
 488
 489 EXPORT_SYMBOL(rxrpc_kernel_accept_call);
 490
 491 /**
 492  * rxrpc_kernel_reject_call - Allow a kernel service to reject an incoming call
 493  * @sock: The socket on which the impending call is waiting
 494  *
 495  * Allow a kernel service to reject an incoming call with a BUSY message,
 496  * assuming the incoming call is still valid.
 497  */
 498 int rxrpc_kernel_reject_call(struct socket *sock)
 499 {
 500         int ret;
 501
 502         _enter("");
 503         ret = rxrpc_reject_call(rxrpc_sk(sock->sk));
 504         _leave(" = %d", ret);
 505         return ret;
 506 }
 507
 508 EXPORT_SYMBOL(rxrpc_kernel_reject_call);