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 <linux/gfp.h>
  21 #include <net/sock.h>
  22 #include <net/af_rxrpc.h>
  23 #include <net/ip.h>
  24 #include "ar-internal.h"
  25
  26 /*
  27  * generate a connection-level abort
  28  */
  29 static int rxrpc_busy(struct rxrpc_local *local, struct sockaddr_rxrpc *srx,
  30                       struct rxrpc_header *hdr)
  31 {
  32         struct msghdr msg;
  33         struct kvec iov[1];
  34         size_t len;
  35         int ret;
  36
  37         _enter("%d,,", local->debug_id);
  38
  39         msg.msg_name    = &srx->transport.sin;
  40         msg.msg_namelen = sizeof(srx->transport.sin);
  41         msg.msg_control = NULL;
  42         msg.msg_controllen = 0;
  43         msg.msg_flags   = 0;
  44
  45         hdr->seq        = 0;
  46         hdr->type       = RXRPC_PACKET_TYPE_BUSY;
  47         hdr->flags      = 0;
  48         hdr->userStatus = 0;
  49         hdr->_rsvd      = 0;
  50
  51         iov[0].iov_base = hdr;
  52         iov[0].iov_len  = sizeof(*hdr);
  53
  54         len = iov[0].iov_len;
  55
  56         hdr->serial = htonl(1);
  57         _proto("Tx BUSY %%%u", ntohl(hdr->serial));
  58
  59         ret = kernel_sendmsg(local->socket, &msg, iov, 1, len);
  60         if (ret < 0) {
  61                 _leave(" = -EAGAIN [sendmsg failed: %d]", ret);
  62                 return -EAGAIN;
  63         }
  64
  65         _leave(" = 0");
  66         return 0;
  67 }
  68
  69 /*
  70  * accept an incoming call that needs peer, transport and/or connection setting
  71  * up
  72  */
  73 static int rxrpc_accept_incoming_call(struct rxrpc_local *local,
  74                                       struct rxrpc_sock *rx,
  75                                       struct sk_buff *skb,
  76                                       struct sockaddr_rxrpc *srx)
  77 {
  78         struct rxrpc_connection *conn;
  79         struct rxrpc_transport *trans;
  80         struct rxrpc_skb_priv *sp, *nsp;
  81         struct rxrpc_peer *peer;
  82         struct rxrpc_call *call;
  83         struct sk_buff *notification;
  84         int ret;
  85
  86         _enter("");
  87
  88         sp = rxrpc_skb(skb);
  89
  90         /* get a notification message to send to the server app */
  91         notification = alloc_skb(0, GFP_NOFS);
  92         if (!notification) {
  93                 _debug("no memory");
  94                 ret = -ENOMEM;
  95                 goto error_nofree;
  96         }
  97         rxrpc_new_skb(notification);
  98         notification->mark = RXRPC_SKB_MARK_NEW_CALL;
  99
 100         peer = rxrpc_get_peer(srx, GFP_NOIO);
 101         if (IS_ERR(peer)) {
 102                 _debug("no peer");
 103                 ret = -EBUSY;
 104                 goto error;
 105         }
 106
 107         trans = rxrpc_get_transport(local, peer, GFP_NOIO);
 108         rxrpc_put_peer(peer);
 109         if (IS_ERR(trans)) {
 110                 _debug("no trans");
 111                 ret = -EBUSY;
 112                 goto error;
 113         }
 114
 115         conn = rxrpc_incoming_connection(trans, &sp->hdr, GFP_NOIO);
 116         rxrpc_put_transport(trans);
 117         if (IS_ERR(conn)) {
 118                 _debug("no conn");
 119                 ret = PTR_ERR(conn);
 120                 goto error;
 121         }
 122
 123         call = rxrpc_incoming_call(rx, conn, &sp->hdr, GFP_NOIO);
 124         rxrpc_put_connection(conn);
 125         if (IS_ERR(call)) {
 126                 _debug("no call");
 127                 ret = PTR_ERR(call);
 128                 goto error;
 129         }
 130
 131         /* attach the call to the socket */
 132         read_lock_bh(&local->services_lock);
 133         if (rx->sk.sk_state == RXRPC_CLOSE)
 134                 goto invalid_service;
 135
 136         write_lock(&rx->call_lock);
 137         if (!test_and_set_bit(RXRPC_CALL_INIT_ACCEPT, &call->flags)) {
 138                 rxrpc_get_call(call);
 139
 140                 spin_lock(&call->conn->state_lock);
 141                 if (sp->hdr.securityIndex > 0 &&
 142                     call->conn->state == RXRPC_CONN_SERVER_UNSECURED) {
 143                         _debug("await conn sec");
 144                         list_add_tail(&call->accept_link, &rx->secureq);
 145                         call->conn->state = RXRPC_CONN_SERVER_CHALLENGING;
 146                         atomic_inc(&call->conn->usage);
 147                         set_bit(RXRPC_CONN_CHALLENGE, &call->conn->events);
 148                         rxrpc_queue_conn(call->conn);
 149                 } else {
 150                         _debug("conn ready");
 151                         call->state = RXRPC_CALL_SERVER_ACCEPTING;
 152                         list_add_tail(&call->accept_link, &rx->acceptq);
 153                         rxrpc_get_call(call);
 154                         nsp = rxrpc_skb(notification);
 155                         nsp->call = call;
 156
 157                         ASSERTCMP(atomic_read(&call->usage), >=, 3);
 158
 159                         _debug("notify");
 160                         spin_lock(&call->lock);
 161                         ret = rxrpc_queue_rcv_skb(call, notification, true,
 162                                                   false);
 163                         spin_unlock(&call->lock);
 164                         notification = NULL;
 165                         BUG_ON(ret < 0);
 166                 }
 167                 spin_unlock(&call->conn->state_lock);
 168
 169                 _debug("queued");
 170         }
 171         write_unlock(&rx->call_lock);
 172
 173         _debug("process");
 174         rxrpc_fast_process_packet(call, skb);
 175
 176         _debug("done");
 177         read_unlock_bh(&local->services_lock);
 178         rxrpc_free_skb(notification);
 179         rxrpc_put_call(call);
 180         _leave(" = 0");
 181         return 0;
 182
 183 invalid_service:
 184         _debug("invalid");
 185         read_unlock_bh(&local->services_lock);
 186
 187         read_lock_bh(&call->state_lock);
 188         if (!test_bit(RXRPC_CALL_RELEASE, &call->flags) &&
 189             !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events)) {
 190                 rxrpc_get_call(call);
 191                 rxrpc_queue_call(call);
 192         }
 193         read_unlock_bh(&call->state_lock);
 194         rxrpc_put_call(call);
 195         ret = -ECONNREFUSED;
 196 error:
 197         rxrpc_free_skb(notification);
 198 error_nofree:
 199         _leave(" = %d", ret);
 200         return ret;
 201 }
 202
 203 /*
 204  * accept incoming calls that need peer, transport and/or connection setting up
 205  * - the packets we get are all incoming client DATA packets that have seq == 1
 206  */
 207 void rxrpc_accept_incoming_calls(struct work_struct *work)
 208 {
 209         struct rxrpc_local *local =
 210                 container_of(work, struct rxrpc_local, acceptor);
 211         struct rxrpc_skb_priv *sp;
 212         struct sockaddr_rxrpc srx;
 213         struct rxrpc_sock *rx;
 214         struct sk_buff *skb;
 215         __be16 service_id;
 216         int ret;
 217
 218         _enter("%d", local->debug_id);
 219
 220         read_lock_bh(&rxrpc_local_lock);
 221         if (atomic_read(&local->usage) > 0)
 222                 rxrpc_get_local(local);
 223         else
 224                 local = NULL;
 225         read_unlock_bh(&rxrpc_local_lock);
 226         if (!local) {
 227                 _leave(" [local dead]");
 228                 return;
 229         }
 230
 231 process_next_packet:
 232         skb = skb_dequeue(&local->accept_queue);
 233         if (!skb) {
 234                 rxrpc_put_local(local);
 235                 _leave("\n");
 236                 return;
 237         }
 238
 239         _net("incoming call skb %p", skb);
 240
 241         sp = rxrpc_skb(skb);
 242
 243         /* determine the remote address */
 244         memset(&srx, 0, sizeof(srx));
 245         srx.srx_family = AF_RXRPC;
 246         srx.transport.family = local->srx.transport.family;
 247         srx.transport_type = local->srx.transport_type;
 248         switch (srx.transport.family) {
 249         case AF_INET:
 250                 srx.transport_len = sizeof(struct sockaddr_in);
 251                 srx.transport.sin.sin_port = udp_hdr(skb)->source;
 252                 srx.transport.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
 253                 break;
 254         default:
 255                 goto busy;
 256         }
 257
 258         /* get the socket providing the service */
 259         service_id = sp->hdr.serviceId;
 260         read_lock_bh(&local->services_lock);
 261         list_for_each_entry(rx, &local->services, listen_link) {
 262                 if (rx->service_id == service_id &&
 263                     rx->sk.sk_state != RXRPC_CLOSE)
 264                         goto found_service;
 265         }
 266         read_unlock_bh(&local->services_lock);
 267         goto invalid_service;
 268
 269 found_service:
 270         _debug("found service %hd", ntohs(rx->service_id));
 271         if (sk_acceptq_is_full(&rx->sk))
 272                 goto backlog_full;
 273         sk_acceptq_added(&rx->sk);
 274         sock_hold(&rx->sk);
 275         read_unlock_bh(&local->services_lock);
 276
 277         ret = rxrpc_accept_incoming_call(local, rx, skb, &srx);
 278         if (ret < 0)
 279                 sk_acceptq_removed(&rx->sk);
 280         sock_put(&rx->sk);
 281         switch (ret) {
 282         case -ECONNRESET: /* old calls are ignored */
 283         case -ECONNABORTED: /* aborted calls are reaborted or ignored */
 284         case 0:
 285                 goto process_next_packet;
 286         case -ECONNREFUSED:
 287                 goto invalid_service;
 288         case -EBUSY:
 289                 goto busy;
 290         case -EKEYREJECTED:
 291                 goto security_mismatch;
 292         default:
 293                 BUG();
 294         }
 295
 296 backlog_full:
 297         read_unlock_bh(&local->services_lock);
 298 busy:
 299         rxrpc_busy(local, &srx, &sp->hdr);
 300         rxrpc_free_skb(skb);
 301         goto process_next_packet;
 302
 303 invalid_service:
 304         skb->priority = RX_INVALID_OPERATION;
 305         rxrpc_reject_packet(local, skb);
 306         goto process_next_packet;
 307
 308         /* can't change connection security type mid-flow */
 309 security_mismatch:
 310         skb->priority = RX_PROTOCOL_ERROR;
 311         rxrpc_reject_packet(local, skb);
 312         goto process_next_packet;
 313 }
 314
 315 /*
 316  * handle acceptance of a call by userspace
 317  * - assign the user call ID to the call at the front of the queue
 318  */
 319 struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
 320                                      unsigned long user_call_ID)
 321 {
 322         struct rxrpc_call *call;
 323         struct rb_node *parent, **pp;
 324         int ret;
 325
 326         _enter(",%lx", user_call_ID);
 327
 328         ASSERT(!irqs_disabled());
 329
 330         write_lock(&rx->call_lock);
 331
 332         ret = -ENODATA;
 333         if (list_empty(&rx->acceptq))
 334                 goto out;
 335
 336         /* check the user ID isn't already in use */
 337         ret = -EBADSLT;
 338         pp = &rx->calls.rb_node;
 339         parent = NULL;
 340         while (*pp) {
 341                 parent = *pp;
 342                 call = rb_entry(parent, struct rxrpc_call, sock_node);
 343
 344                 if (user_call_ID < call->user_call_ID)
 345                         pp = &(*pp)->rb_left;
 346                 else if (user_call_ID > call->user_call_ID)
 347                         pp = &(*pp)->rb_right;
 348                 else
 349                         goto out;
 350         }
 351
 352         /* dequeue the first call and check it's still valid */
 353         call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
 354         list_del_init(&call->accept_link);
 355         sk_acceptq_removed(&rx->sk);
 356
 357         write_lock_bh(&call->state_lock);
 358         switch (call->state) {
 359         case RXRPC_CALL_SERVER_ACCEPTING:
 360                 call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
 361                 break;
 362         case RXRPC_CALL_REMOTELY_ABORTED:
 363         case RXRPC_CALL_LOCALLY_ABORTED:
 364                 ret = -ECONNABORTED;
 365                 goto out_release;
 366         case RXRPC_CALL_NETWORK_ERROR:
 367                 ret = call->conn->error;
 368                 goto out_release;
 369         case RXRPC_CALL_DEAD:
 370                 ret = -ETIME;
 371                 goto out_discard;
 372         default:
 373                 BUG();
 374         }
 375
 376         /* formalise the acceptance */
 377         call->user_call_ID = user_call_ID;
 378         rb_link_node(&call->sock_node, parent, pp);
 379         rb_insert_color(&call->sock_node, &rx->calls);
 380         if (test_and_set_bit(RXRPC_CALL_HAS_USERID, &call->flags))
 381                 BUG();
 382         if (test_and_set_bit(RXRPC_CALL_ACCEPTED, &call->events))
 383                 BUG();
 384         rxrpc_queue_call(call);
 385
 386         rxrpc_get_call(call);
 387         write_unlock_bh(&call->state_lock);
 388         write_unlock(&rx->call_lock);
 389         _leave(" = %p{%d}", call, call->debug_id);
 390         return call;
 391
 392         /* if the call is already dying or dead, then we leave the socket's ref
 393          * on it to be released by rxrpc_dead_call_expired() as induced by
 394          * rxrpc_release_call() */
 395 out_release:
 396         _debug("release %p", call);
 397         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
 398             !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
 399                 rxrpc_queue_call(call);
 400 out_discard:
 401         write_unlock_bh(&call->state_lock);
 402         _debug("discard %p", call);
 403 out:
 404         write_unlock(&rx->call_lock);
 405         _leave(" = %d", ret);
 406         return ERR_PTR(ret);
 407 }
 408
 409 /*
 410  * handle rejectance of a call by userspace
 411  * - reject the call at the front of the queue
 412  */
 413 int rxrpc_reject_call(struct rxrpc_sock *rx)
 414 {
 415         struct rxrpc_call *call;
 416         int ret;
 417
 418         _enter("");
 419
 420         ASSERT(!irqs_disabled());
 421
 422         write_lock(&rx->call_lock);
 423
 424         ret = -ENODATA;
 425         if (list_empty(&rx->acceptq))
 426                 goto out;
 427
 428         /* dequeue the first call and check it's still valid */
 429         call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
 430         list_del_init(&call->accept_link);
 431         sk_acceptq_removed(&rx->sk);
 432
 433         write_lock_bh(&call->state_lock);
 434         switch (call->state) {
 435         case RXRPC_CALL_SERVER_ACCEPTING:
 436                 call->state = RXRPC_CALL_SERVER_BUSY;
 437                 if (test_and_set_bit(RXRPC_CALL_REJECT_BUSY, &call->events))
 438                         rxrpc_queue_call(call);
 439                 ret = 0;
 440                 goto out_release;
 441         case RXRPC_CALL_REMOTELY_ABORTED:
 442         case RXRPC_CALL_LOCALLY_ABORTED:
 443                 ret = -ECONNABORTED;
 444                 goto out_release;
 445         case RXRPC_CALL_NETWORK_ERROR:
 446                 ret = call->conn->error;
 447                 goto out_release;
 448         case RXRPC_CALL_DEAD:
 449                 ret = -ETIME;
 450                 goto out_discard;
 451         default:
 452                 BUG();
 453         }
 454
 455         /* if the call is already dying or dead, then we leave the socket's ref
 456          * on it to be released by rxrpc_dead_call_expired() as induced by
 457          * rxrpc_release_call() */
 458 out_release:
 459         _debug("release %p", call);
 460         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
 461             !test_and_set_bit(RXRPC_CALL_RELEASE, &call->events))
 462                 rxrpc_queue_call(call);
 463 out_discard:
 464         write_unlock_bh(&call->state_lock);
 465         _debug("discard %p", call);
 466 out:
 467         write_unlock(&rx->call_lock);
 468         _leave(" = %d", ret);
 469         return ret;
 470 }
 471
 472 /**
 473  * rxrpc_kernel_accept_call - Allow a kernel service to accept an incoming call
 474  * @sock: The socket on which the impending call is waiting
 475  * @user_call_ID: The tag to attach to the call
 476  *
 477  * Allow a kernel service to accept an incoming call, assuming the incoming
 478  * call is still valid.
 479  */
 480 struct rxrpc_call *rxrpc_kernel_accept_call(struct socket *sock,
 481                                             unsigned long user_call_ID)
 482 {
 483         struct rxrpc_call *call;
 484
 485         _enter(",%lx", user_call_ID);
 486         call = rxrpc_accept_call(rxrpc_sk(sock->sk), user_call_ID);
 487         _leave(" = %p", call);
 488         return call;
 489 }
 490
 491 EXPORT_SYMBOL(rxrpc_kernel_accept_call);
 492
 493 /**
 494  * rxrpc_kernel_reject_call - Allow a kernel service to reject an incoming call
 495  * @sock: The socket on which the impending call is waiting
 496  *
 497  * Allow a kernel service to reject an incoming call with a BUSY message,
 498  * assuming the incoming call is still valid.
 499  */
 500 int rxrpc_kernel_reject_call(struct socket *sock)
 501 {
 502         int ret;
 503
 504         _enter("");
 505         ret = rxrpc_reject_call(rxrpc_sk(sock->sk));
 506         _leave(" = %d", ret);
 507         return ret;
 508 }
 509
 510 EXPORT_SYMBOL(rxrpc_kernel_reject_call);