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                         BUG_ON(ret < 0);
 160                 }
 161                 spin_unlock(&call->conn->state_lock);
 162
 163                 _debug("queued");
 164         }
 165         write_unlock(&rx->call_lock);
 166
 167         _debug("process");
 168         rxrpc_fast_process_packet(call, skb);
 169
 170         _debug("done");
 171         read_unlock_bh(&local->services_lock);
 172         rxrpc_free_skb(notification);
 173         rxrpc_put_call(call);
 174         _leave(" = 0");
 175         return 0;
 176
 177 invalid_service:
 178         _debug("invalid");
 179         read_unlock_bh(&local->services_lock);
 180
 181         read_lock_bh(&call->state_lock);
 182         if (!test_bit(RXRPC_CALL_RELEASE, &call->flags) &&
 183             !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events)) {
 184                 rxrpc_get_call(call);
 185                 rxrpc_queue_call(call);
 186         }
 187         read_unlock_bh(&call->state_lock);
 188         rxrpc_put_call(call);
 189         ret = -ECONNREFUSED;
 190 error:
 191         rxrpc_free_skb(notification);
 192         _leave(" = %d", ret);
 193         return ret;
 194 }
 195
 196 /*
 197  * accept incoming calls that need peer, transport and/or connection setting up
 198  * - the packets we get are all incoming client DATA packets that have seq == 1
 199  */
 200 void rxrpc_accept_incoming_calls(struct work_struct *work)
 201 {
 202         struct rxrpc_local *local =
 203                 container_of(work, struct rxrpc_local, acceptor);
 204         struct rxrpc_skb_priv *sp;
 205         struct sockaddr_rxrpc srx;
 206         struct rxrpc_sock *rx;
 207         struct sk_buff *skb;
 208         __be16 service_id;
 209         int ret;
 210
 211         _enter("%d", local->debug_id);
 212
 213         read_lock_bh(&rxrpc_local_lock);
 214         if (atomic_read(&local->usage) > 0)
 215                 rxrpc_get_local(local);
 216         else
 217                 local = NULL;
 218         read_unlock_bh(&rxrpc_local_lock);
 219         if (!local) {
 220                 _leave(" [local dead]");
 221                 return;
 222         }
 223
 224 process_next_packet:
 225         skb = skb_dequeue(&local->accept_queue);
 226         if (!skb) {
 227                 rxrpc_put_local(local);
 228                 _leave("\n");
 229                 return;
 230         }
 231
 232         _net("incoming call skb %p", skb);
 233
 234         sp = rxrpc_skb(skb);
 235
 236         /* determine the remote address */
 237         memset(&srx, 0, sizeof(srx));
 238         srx.srx_family = AF_RXRPC;
 239         srx.transport.family = local->srx.transport.family;
 240         srx.transport_type = local->srx.transport_type;
 241         switch (srx.transport.family) {
 242         case AF_INET:
 243                 srx.transport_len = sizeof(struct sockaddr_in);
 244                 srx.transport.sin.sin_port = udp_hdr(skb)->source;
 245                 srx.transport.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
 246                 break;
 247         default:
 248                 goto busy;
 249         }
 250
 251         /* get the socket providing the service */
 252         service_id = sp->hdr.serviceId;
 253         read_lock_bh(&local->services_lock);
 254         list_for_each_entry(rx, &local->services, listen_link) {
 255                 if (rx->service_id == service_id &&
 256                     rx->sk.sk_state != RXRPC_CLOSE)
 257                         goto found_service;
 258         }
 259         read_unlock_bh(&local->services_lock);
 260         goto invalid_service;
 261
 262 found_service:
 263         _debug("found service %hd", ntohs(rx->service_id));
 264         if (sk_acceptq_is_full(&rx->sk))
 265                 goto backlog_full;
 266         sk_acceptq_added(&rx->sk);
 267         sock_hold(&rx->sk);
 268         read_unlock_bh(&local->services_lock);
 269
 270         ret = rxrpc_accept_incoming_call(local, rx, skb, &srx);
 271         if (ret < 0)
 272                 sk_acceptq_removed(&rx->sk);
 273         sock_put(&rx->sk);
 274         switch (ret) {
 275         case -ECONNRESET: /* old calls are ignored */
 276         case -ECONNABORTED: /* aborted calls are reaborted or ignored */
 277         case 0:
 278                 goto process_next_packet;
 279         case -ECONNREFUSED:
 280                 goto invalid_service;
 281         case -EBUSY:
 282                 goto busy;
 283         case -EKEYREJECTED:
 284                 goto security_mismatch;
 285         default:
 286                 BUG();
 287         }
 288
 289 backlog_full:
 290         read_unlock_bh(&local->services_lock);
 291 busy:
 292         rxrpc_busy(local, &srx, &sp->hdr);
 293         rxrpc_free_skb(skb);
 294         goto process_next_packet;
 295
 296 invalid_service:
 297         skb->priority = RX_INVALID_OPERATION;
 298         rxrpc_reject_packet(local, skb);
 299         goto process_next_packet;
 300
 301         /* can't change connection security type mid-flow */
 302 security_mismatch:
 303         skb->priority = RX_PROTOCOL_ERROR;
 304         rxrpc_reject_packet(local, skb);
 305         goto process_next_packet;
 306 }
 307
 308 /*
 309  * handle acceptance of a call by userspace
 310  * - assign the user call ID to the call at the front of the queue
 311  */
 312 struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
 313                                      unsigned long user_call_ID)
 314 {
 315         struct rxrpc_call *call;
 316         struct rb_node *parent, **pp;
 317         int ret;
 318
 319         _enter(",%lx", user_call_ID);
 320
 321         ASSERT(!irqs_disabled());
 322
 323         write_lock(&rx->call_lock);
 324
 325         ret = -ENODATA;
 326         if (list_empty(&rx->acceptq))
 327                 goto out;
 328
 329         /* check the user ID isn't already in use */
 330         ret = -EBADSLT;
 331         pp = &rx->calls.rb_node;
 332         parent = NULL;
 333         while (*pp) {
 334                 parent = *pp;
 335                 call = rb_entry(parent, struct rxrpc_call, sock_node);
 336
 337                 if (user_call_ID < call->user_call_ID)
 338                         pp = &(*pp)->rb_left;
 339                 else if (user_call_ID > call->user_call_ID)
 340                         pp = &(*pp)->rb_right;
 341                 else
 342                         goto out;
 343         }
 344
 345         /* dequeue the first call and check it's still valid */
 346         call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
 347         list_del_init(&call->accept_link);
 348         sk_acceptq_removed(&rx->sk);
 349
 350         write_lock_bh(&call->state_lock);
 351         switch (call->state) {
 352         case RXRPC_CALL_SERVER_ACCEPTING:
 353                 call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
 354                 break;
 355         case RXRPC_CALL_REMOTELY_ABORTED:
 356         case RXRPC_CALL_LOCALLY_ABORTED:
 357                 ret = -ECONNABORTED;
 358                 goto out_release;
 359         case RXRPC_CALL_NETWORK_ERROR:
 360                 ret = call->conn->error;
 361                 goto out_release;
 362         case RXRPC_CALL_DEAD:
 363                 ret = -ETIME;
 364                 goto out_discard;
 365         default:
 366                 BUG();
 367         }
 368
 369         /* formalise the acceptance */
 370         call->user_call_ID = user_call_ID;
 371         rb_link_node(&call->sock_node, parent, pp);
 372         rb_insert_color(&call->sock_node, &rx->calls);
 373         if (test_and_set_bit(RXRPC_CALL_HAS_USERID, &call->flags))
 374                 BUG();
 375         if (test_and_set_bit(RXRPC_CALL_ACCEPTED, &call->events))
 376                 BUG();
 377         rxrpc_queue_call(call);
 378
 379         rxrpc_get_call(call);
 380         write_unlock_bh(&call->state_lock);
 381         write_unlock(&rx->call_lock);
 382         _leave(" = %p{%d}", call, call->debug_id);
 383         return call;
 384
 385         /* if the call is already dying or dead, then we leave the socket's ref
 386          * on it to be released by rxrpc_dead_call_expired() as induced by
 387          * rxrpc_release_call() */
 388 out_release:
 389         _debug("release %p", call);
 390         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
 391             !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
 392                 rxrpc_queue_call(call);
 393 out_discard:
 394         write_unlock_bh(&call->state_lock);
 395         _debug("discard %p", call);
 396 out:
 397         write_unlock(&rx->call_lock);
 398         _leave(" = %d", ret);
 399         return ERR_PTR(ret);
 400 }
 401
 402 /*
 403  * handle rejectance of a call by userspace
 404  * - reject the call at the front of the queue
 405  */
 406 int rxrpc_reject_call(struct rxrpc_sock *rx)
 407 {
 408         struct rxrpc_call *call;
 409         int ret;
 410
 411         _enter("");
 412
 413         ASSERT(!irqs_disabled());
 414
 415         write_lock(&rx->call_lock);
 416
 417         ret = -ENODATA;
 418         if (list_empty(&rx->acceptq))
 419                 goto out;
 420
 421         /* dequeue the first call and check it's still valid */
 422         call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
 423         list_del_init(&call->accept_link);
 424         sk_acceptq_removed(&rx->sk);
 425
 426         write_lock_bh(&call->state_lock);
 427         switch (call->state) {
 428         case RXRPC_CALL_SERVER_ACCEPTING:
 429                 call->state = RXRPC_CALL_SERVER_BUSY;
 430                 if (test_and_set_bit(RXRPC_CALL_REJECT_BUSY, &call->events))
 431                         rxrpc_queue_call(call);
 432                 ret = 0;
 433                 goto out_release;
 434         case RXRPC_CALL_REMOTELY_ABORTED:
 435         case RXRPC_CALL_LOCALLY_ABORTED:
 436                 ret = -ECONNABORTED;
 437                 goto out_release;
 438         case RXRPC_CALL_NETWORK_ERROR:
 439                 ret = call->conn->error;
 440                 goto out_release;
 441         case RXRPC_CALL_DEAD:
 442                 ret = -ETIME;
 443                 goto out_discard;
 444         default:
 445                 BUG();
 446         }
 447
 448         /* if the call is already dying or dead, then we leave the socket's ref
 449          * on it to be released by rxrpc_dead_call_expired() as induced by
 450          * rxrpc_release_call() */
 451 out_release:
 452         _debug("release %p", call);
 453         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
 454             !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
 455                 rxrpc_queue_call(call);
 456 out_discard:
 457         write_unlock_bh(&call->state_lock);
 458         _debug("discard %p", call);
 459 out:
 460         write_unlock(&rx->call_lock);
 461         _leave(" = %d", ret);
 462         return ret;
 463 }
 464
 465 /**
 466  * rxrpc_kernel_accept_call - Allow a kernel service to accept an incoming call
 467  * @sock: The socket on which the impending call is waiting
 468  * @user_call_ID: The tag to attach to the call
 469  *
 470  * Allow a kernel service to accept an incoming call, assuming the incoming
 471  * call is still valid.
 472  */
 473 struct rxrpc_call *rxrpc_kernel_accept_call(struct socket *sock,
 474                                             unsigned long user_call_ID)
 475 {
 476         struct rxrpc_call *call;
 477
 478         _enter(",%lx", user_call_ID);
 479         call = rxrpc_accept_call(rxrpc_sk(sock->sk), user_call_ID);
 480         _leave(" = %p", call);
 481         return call;
 482 }
 483
 484 EXPORT_SYMBOL(rxrpc_kernel_accept_call);
 485
 486 /**
 487  * rxrpc_kernel_reject_call - Allow a kernel service to reject an incoming call
 488  * @sock: The socket on which the impending call is waiting
 489  *
 490  * Allow a kernel service to reject an incoming call with a BUSY message,
 491  * assuming the incoming call is still valid.
 492  */
 493 int rxrpc_kernel_reject_call(struct socket *sock)
 494 {
 495         int ret;
 496
 497         _enter("");
 498         ret = rxrpc_reject_call(rxrpc_sk(sock->sk));
 499         _leave(" = %d", ret);
 500         return ret;
 501 }
 502
 503 EXPORT_SYMBOL(rxrpc_kernel_reject_call);