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_wire_header *whdr)
  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         whdr->type      = RXRPC_PACKET_TYPE_BUSY;
  40         whdr->serial    = htonl(1);
  41
  42         msg.msg_name    = &srx->transport.sin;
  43         msg.msg_namelen = sizeof(srx->transport.sin);
  44         msg.msg_control = NULL;
  45         msg.msg_controllen = 0;
  46         msg.msg_flags   = 0;
  47
  48         iov[0].iov_base = whdr;
  49         iov[0].iov_len  = sizeof(*whdr);
  50
  51         len = iov[0].iov_len;
  52
  53         _proto("Tx BUSY %%1");
  54
  55         ret = kernel_sendmsg(local->socket, &msg, iov, 1, len);
  56         if (ret < 0) {
  57                 _leave(" = -EAGAIN [sendmsg failed: %d]", ret);
  58                 return -EAGAIN;
  59         }
  60
  61         _leave(" = 0");
  62         return 0;
  63 }
  64
  65 /*
  66  * accept an incoming call that needs peer, transport and/or connection setting
  67  * up
  68  */
  69 static int rxrpc_accept_incoming_call(struct rxrpc_local *local,
  70                                       struct rxrpc_sock *rx,
  71                                       struct sk_buff *skb,
  72                                       struct sockaddr_rxrpc *srx)
  73 {
  74         struct rxrpc_connection *conn;
  75         struct rxrpc_transport *trans;
  76         struct rxrpc_skb_priv *sp, *nsp;
  77         struct rxrpc_peer *peer;
  78         struct rxrpc_call *call;
  79         struct sk_buff *notification;
  80         int ret;
  81
  82         _enter("");
  83
  84         sp = rxrpc_skb(skb);
  85
  86         /* get a notification message to send to the server app */
  87         notification = alloc_skb(0, GFP_NOFS);
  88         if (!notification) {
  89                 _debug("no memory");
  90                 ret = -ENOMEM;
  91                 goto error_nofree;
  92         }
  93         rxrpc_new_skb(notification);
  94         notification->mark = RXRPC_SKB_MARK_NEW_CALL;
  95
  96         peer = rxrpc_get_peer(srx, GFP_NOIO);
  97         if (IS_ERR(peer)) {
  98                 _debug("no peer");
  99                 ret = -EBUSY;
 100                 goto error;
 101         }
 102
 103         trans = rxrpc_get_transport(local, peer, GFP_NOIO);
 104         rxrpc_put_peer(peer);
 105         if (IS_ERR(trans)) {
 106                 _debug("no trans");
 107                 ret = -EBUSY;
 108                 goto error;
 109         }
 110
 111         conn = rxrpc_incoming_connection(trans, &sp->hdr);
 112         rxrpc_put_transport(trans);
 113         if (IS_ERR(conn)) {
 114                 _debug("no conn");
 115                 ret = PTR_ERR(conn);
 116                 goto error;
 117         }
 118
 119         call = rxrpc_incoming_call(rx, conn, &sp->hdr);
 120         rxrpc_put_connection(conn);
 121         if (IS_ERR(call)) {
 122                 _debug("no call");
 123                 ret = PTR_ERR(call);
 124                 goto error;
 125         }
 126
 127         /* attach the call to the socket */
 128         read_lock_bh(&local->services_lock);
 129         if (rx->sk.sk_state == RXRPC_CLOSE)
 130                 goto invalid_service;
 131
 132         write_lock(&rx->call_lock);
 133         if (!test_and_set_bit(RXRPC_CALL_INIT_ACCEPT, &call->flags)) {
 134                 rxrpc_get_call(call);
 135
 136                 spin_lock(&call->conn->state_lock);
 137                 if (sp->hdr.securityIndex > 0 &&
 138                     call->conn->state == RXRPC_CONN_SERVER_UNSECURED) {
 139                         _debug("await conn sec");
 140                         list_add_tail(&call->accept_link, &rx->secureq);
 141                         call->conn->state = RXRPC_CONN_SERVER_CHALLENGING;
 142                         atomic_inc(&call->conn->usage);
 143                         set_bit(RXRPC_CONN_CHALLENGE, &call->conn->events);
 144                         rxrpc_queue_conn(call->conn);
 145                 } else {
 146                         _debug("conn ready");
 147                         call->state = RXRPC_CALL_SERVER_ACCEPTING;
 148                         list_add_tail(&call->accept_link, &rx->acceptq);
 149                         rxrpc_get_call(call);
 150                         nsp = rxrpc_skb(notification);
 151                         nsp->call = call;
 152
 153                         ASSERTCMP(atomic_read(&call->usage), >=, 3);
 154
 155                         _debug("notify");
 156                         spin_lock(&call->lock);
 157                         ret = rxrpc_queue_rcv_skb(call, notification, true,
 158                                                   false);
 159                         spin_unlock(&call->lock);
 160                         notification = NULL;
 161                         BUG_ON(ret < 0);
 162                 }
 163                 spin_unlock(&call->conn->state_lock);
 164
 165                 _debug("queued");
 166         }
 167         write_unlock(&rx->call_lock);
 168
 169         _debug("process");
 170         rxrpc_fast_process_packet(call, skb);
 171
 172         _debug("done");
 173         read_unlock_bh(&local->services_lock);
 174         rxrpc_free_skb(notification);
 175         rxrpc_put_call(call);
 176         _leave(" = 0");
 177         return 0;
 178
 179 invalid_service:
 180         _debug("invalid");
 181         read_unlock_bh(&local->services_lock);
 182
 183         read_lock_bh(&call->state_lock);
 184         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
 185             !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events)) {
 186                 rxrpc_get_call(call);
 187                 rxrpc_queue_call(call);
 188         }
 189         read_unlock_bh(&call->state_lock);
 190         rxrpc_put_call(call);
 191         ret = -ECONNREFUSED;
 192 error:
 193         rxrpc_free_skb(notification);
 194 error_nofree:
 195         _leave(" = %d", ret);
 196         return ret;
 197 }
 198
 199 /*
 200  * accept incoming calls that need peer, transport and/or connection setting up
 201  * - the packets we get are all incoming client DATA packets that have seq == 1
 202  */
 203 void rxrpc_accept_incoming_calls(struct work_struct *work)
 204 {
 205         struct rxrpc_local *local =
 206                 container_of(work, struct rxrpc_local, acceptor);
 207         struct rxrpc_skb_priv *sp;
 208         struct sockaddr_rxrpc srx;
 209         struct rxrpc_sock *rx;
 210         struct rxrpc_wire_header whdr;
 211         struct sk_buff *skb;
 212         int ret;
 213
 214         _enter("%d", local->debug_id);
 215
 216         read_lock_bh(&rxrpc_local_lock);
 217         if (atomic_read(&local->usage) > 0)
 218                 rxrpc_get_local(local);
 219         else
 220                 local = NULL;
 221         read_unlock_bh(&rxrpc_local_lock);
 222         if (!local) {
 223                 _leave(" [local dead]");
 224                 return;
 225         }
 226
 227 process_next_packet:
 228         skb = skb_dequeue(&local->accept_queue);
 229         if (!skb) {
 230                 rxrpc_put_local(local);
 231                 _leave("\n");
 232                 return;
 233         }
 234
 235         _net("incoming call skb %p", skb);
 236
 237         sp = rxrpc_skb(skb);
 238
 239         /* Set up a response packet header in case we need it */
 240         whdr.epoch      = htonl(sp->hdr.epoch);
 241         whdr.cid        = htonl(sp->hdr.cid);
 242         whdr.callNumber = htonl(sp->hdr.callNumber);
 243         whdr.seq        = htonl(sp->hdr.seq);
 244         whdr.serial     = 0;
 245         whdr.flags      = 0;
 246         whdr.type       = 0;
 247         whdr.userStatus = 0;
 248         whdr.securityIndex = sp->hdr.securityIndex;
 249         whdr._rsvd      = 0;
 250         whdr.serviceId  = htons(sp->hdr.serviceId);
 251
 252         /* determine the remote address */
 253         memset(&srx, 0, sizeof(srx));
 254         srx.srx_family = AF_RXRPC;
 255         srx.transport.family = local->srx.transport.family;
 256         srx.transport_type = local->srx.transport_type;
 257         switch (srx.transport.family) {
 258         case AF_INET:
 259                 srx.transport_len = sizeof(struct sockaddr_in);
 260                 srx.transport.sin.sin_port = udp_hdr(skb)->source;
 261                 srx.transport.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
 262                 break;
 263         default:
 264                 goto busy;
 265         }
 266
 267         /* get the socket providing the service */
 268         read_lock_bh(&local->services_lock);
 269         list_for_each_entry(rx, &local->services, listen_link) {
 270                 if (rx->srx.srx_service == sp->hdr.serviceId &&
 271                     rx->sk.sk_state != RXRPC_CLOSE)
 272                         goto found_service;
 273         }
 274         read_unlock_bh(&local->services_lock);
 275         goto invalid_service;
 276
 277 found_service:
 278         _debug("found service %hd", rx->srx.srx_service);
 279         if (sk_acceptq_is_full(&rx->sk))
 280                 goto backlog_full;
 281         sk_acceptq_added(&rx->sk);
 282         sock_hold(&rx->sk);
 283         read_unlock_bh(&local->services_lock);
 284
 285         ret = rxrpc_accept_incoming_call(local, rx, skb, &srx);
 286         if (ret < 0)
 287                 sk_acceptq_removed(&rx->sk);
 288         sock_put(&rx->sk);
 289         switch (ret) {
 290         case -ECONNRESET: /* old calls are ignored */
 291         case -ECONNABORTED: /* aborted calls are reaborted or ignored */
 292         case 0:
 293                 goto process_next_packet;
 294         case -ECONNREFUSED:
 295                 goto invalid_service;
 296         case -EBUSY:
 297                 goto busy;
 298         case -EKEYREJECTED:
 299                 goto security_mismatch;
 300         default:
 301                 BUG();
 302         }
 303
 304 backlog_full:
 305         read_unlock_bh(&local->services_lock);
 306 busy:
 307         rxrpc_busy(local, &srx, &whdr);
 308         rxrpc_free_skb(skb);
 309         goto process_next_packet;
 310
 311 invalid_service:
 312         skb->priority = RX_INVALID_OPERATION;
 313         rxrpc_reject_packet(local, skb);
 314         goto process_next_packet;
 315
 316         /* can't change connection security type mid-flow */
 317 security_mismatch:
 318         skb->priority = RX_PROTOCOL_ERROR;
 319         rxrpc_reject_packet(local, skb);
 320         goto process_next_packet;
 321 }
 322
 323 /*
 324  * handle acceptance of a call by userspace
 325  * - assign the user call ID to the call at the front of the queue
 326  */
 327 struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
 328                                      unsigned long user_call_ID)
 329 {
 330         struct rxrpc_call *call;
 331         struct rb_node *parent, **pp;
 332         int ret;
 333
 334         _enter(",%lx", user_call_ID);
 335
 336         ASSERT(!irqs_disabled());
 337
 338         write_lock(&rx->call_lock);
 339
 340         ret = -ENODATA;
 341         if (list_empty(&rx->acceptq))
 342                 goto out;
 343
 344         /* check the user ID isn't already in use */
 345         ret = -EBADSLT;
 346         pp = &rx->calls.rb_node;
 347         parent = NULL;
 348         while (*pp) {
 349                 parent = *pp;
 350                 call = rb_entry(parent, struct rxrpc_call, sock_node);
 351
 352                 if (user_call_ID < call->user_call_ID)
 353                         pp = &(*pp)->rb_left;
 354                 else if (user_call_ID > call->user_call_ID)
 355                         pp = &(*pp)->rb_right;
 356                 else
 357                         goto out;
 358         }
 359
 360         /* dequeue the first call and check it's still valid */
 361         call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
 362         list_del_init(&call->accept_link);
 363         sk_acceptq_removed(&rx->sk);
 364
 365         write_lock_bh(&call->state_lock);
 366         switch (call->state) {
 367         case RXRPC_CALL_SERVER_ACCEPTING:
 368                 call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
 369                 break;
 370         case RXRPC_CALL_REMOTELY_ABORTED:
 371         case RXRPC_CALL_LOCALLY_ABORTED:
 372                 ret = -ECONNABORTED;
 373                 goto out_release;
 374         case RXRPC_CALL_NETWORK_ERROR:
 375                 ret = call->conn->error;
 376                 goto out_release;
 377         case RXRPC_CALL_DEAD:
 378                 ret = -ETIME;
 379                 goto out_discard;
 380         default:
 381                 BUG();
 382         }
 383
 384         /* formalise the acceptance */
 385         call->user_call_ID = user_call_ID;
 386         rb_link_node(&call->sock_node, parent, pp);
 387         rb_insert_color(&call->sock_node, &rx->calls);
 388         if (test_and_set_bit(RXRPC_CALL_HAS_USERID, &call->flags))
 389                 BUG();
 390         if (test_and_set_bit(RXRPC_CALL_EV_ACCEPTED, &call->events))
 391                 BUG();
 392         rxrpc_queue_call(call);
 393
 394         rxrpc_get_call(call);
 395         write_unlock_bh(&call->state_lock);
 396         write_unlock(&rx->call_lock);
 397         _leave(" = %p{%d}", call, call->debug_id);
 398         return call;
 399
 400         /* if the call is already dying or dead, then we leave the socket's ref
 401          * on it to be released by rxrpc_dead_call_expired() as induced by
 402          * rxrpc_release_call() */
 403 out_release:
 404         _debug("release %p", call);
 405         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
 406             !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
 407                 rxrpc_queue_call(call);
 408 out_discard:
 409         write_unlock_bh(&call->state_lock);
 410         _debug("discard %p", call);
 411 out:
 412         write_unlock(&rx->call_lock);
 413         _leave(" = %d", ret);
 414         return ERR_PTR(ret);
 415 }
 416
 417 /*
 418  * Handle rejection of a call by userspace
 419  * - reject the call at the front of the queue
 420  */
 421 int rxrpc_reject_call(struct rxrpc_sock *rx)
 422 {
 423         struct rxrpc_call *call;
 424         int ret;
 425
 426         _enter("");
 427
 428         ASSERT(!irqs_disabled());
 429
 430         write_lock(&rx->call_lock);
 431
 432         ret = -ENODATA;
 433         if (list_empty(&rx->acceptq))
 434                 goto out;
 435
 436         /* dequeue the first call and check it's still valid */
 437         call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
 438         list_del_init(&call->accept_link);
 439         sk_acceptq_removed(&rx->sk);
 440
 441         write_lock_bh(&call->state_lock);
 442         switch (call->state) {
 443         case RXRPC_CALL_SERVER_ACCEPTING:
 444                 call->state = RXRPC_CALL_SERVER_BUSY;
 445                 if (test_and_set_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events))
 446                         rxrpc_queue_call(call);
 447                 ret = 0;
 448                 goto out_release;
 449         case RXRPC_CALL_REMOTELY_ABORTED:
 450         case RXRPC_CALL_LOCALLY_ABORTED:
 451                 ret = -ECONNABORTED;
 452                 goto out_release;
 453         case RXRPC_CALL_NETWORK_ERROR:
 454                 ret = call->conn->error;
 455                 goto out_release;
 456         case RXRPC_CALL_DEAD:
 457                 ret = -ETIME;
 458                 goto out_discard;
 459         default:
 460                 BUG();
 461         }
 462
 463         /* if the call is already dying or dead, then we leave the socket's ref
 464          * on it to be released by rxrpc_dead_call_expired() as induced by
 465          * rxrpc_release_call() */
 466 out_release:
 467         _debug("release %p", call);
 468         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
 469             !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
 470                 rxrpc_queue_call(call);
 471 out_discard:
 472         write_unlock_bh(&call->state_lock);
 473         _debug("discard %p", call);
 474 out:
 475         write_unlock(&rx->call_lock);
 476         _leave(" = %d", ret);
 477         return ret;
 478 }
 479
 480 /**
 481  * rxrpc_kernel_accept_call - Allow a kernel service to accept an incoming call
 482  * @sock: The socket on which the impending call is waiting
 483  * @user_call_ID: The tag to attach to the call
 484  *
 485  * Allow a kernel service to accept an incoming call, assuming the incoming
 486  * call is still valid.
 487  */
 488 struct rxrpc_call *rxrpc_kernel_accept_call(struct socket *sock,
 489                                             unsigned long user_call_ID)
 490 {
 491         struct rxrpc_call *call;
 492
 493         _enter(",%lx", user_call_ID);
 494         call = rxrpc_accept_call(rxrpc_sk(sock->sk), user_call_ID);
 495         _leave(" = %p", call);
 496         return call;
 497 }
 498 EXPORT_SYMBOL(rxrpc_kernel_accept_call);
 499
 500 /**
 501  * rxrpc_kernel_reject_call - Allow a kernel service to reject an incoming call
 502  * @sock: The socket on which the impending call is waiting
 503  *
 504  * Allow a kernel service to reject an incoming call with a BUSY message,
 505  * assuming the incoming call is still valid.
 506  */
 507 int rxrpc_kernel_reject_call(struct socket *sock)
 508 {
 509         int ret;
 510
 511         _enter("");
 512         ret = rxrpc_reject_call(rxrpc_sk(sock->sk));
 513         _leave(" = %d", ret);
 514         return ret;
 515 }
 516 EXPORT_SYMBOL(rxrpc_kernel_reject_call);