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