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