net/rxrpc/call_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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/module.h>
  15 #include <linux/net.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/errqueue.h>
  18 #include <linux/udp.h>
  19 #include <linux/in.h>
  20 #include <linux/in6.h>
  21 #include <linux/icmp.h>
  22 #include <linux/gfp.h>
  23 #include <net/sock.h>
  24 #include <net/af_rxrpc.h>
  25 #include <net/ip.h>
  26 #include "ar-internal.h"
  27
  28 /*
  29  * generate a connection-level abort
  30  */
  31 static int rxrpc_busy(struct rxrpc_local *local, struct sockaddr_rxrpc *srx,
  32                       struct rxrpc_wire_header *whdr)
  33 {
  34         struct msghdr msg;
  35         struct kvec iov[1];
  36         size_t len;
  37         int ret;
  38
  39         _enter("%d,,", local->debug_id);
  40
  41         whdr->type      = RXRPC_PACKET_TYPE_BUSY;
  42         whdr->serial    = htonl(1);
  43
  44         msg.msg_name    = &srx->transport.sin;
  45         msg.msg_namelen = sizeof(srx->transport.sin);
  46         msg.msg_control = NULL;
  47         msg.msg_controllen = 0;
  48         msg.msg_flags   = 0;
  49
  50         iov[0].iov_base = whdr;
  51         iov[0].iov_len  = sizeof(*whdr);
  52
  53         len = iov[0].iov_len;
  54
  55         _proto("Tx BUSY %%1");
  56
  57         ret = kernel_sendmsg(local->socket, &msg, iov, 1, len);
  58         if (ret < 0) {
  59                 _leave(" = -EAGAIN [sendmsg failed: %d]", ret);
  60                 return -EAGAIN;
  61         }
  62
  63         _leave(" = 0");
  64         return 0;
  65 }
  66
  67 /*
  68  * accept an incoming call that needs peer, transport and/or connection setting
  69  * up
  70  */
  71 static int rxrpc_accept_incoming_call(struct rxrpc_local *local,
  72                                       struct rxrpc_sock *rx,
  73                                       struct sk_buff *skb,
  74                                       struct sockaddr_rxrpc *srx)
  75 {
  76         struct rxrpc_connection *conn;
  77         struct rxrpc_transport *trans;
  78         struct rxrpc_skb_priv *sp, *nsp;
  79         struct rxrpc_peer *peer;
  80         struct rxrpc_call *call;
  81         struct sk_buff *notification;
  82         int ret;
  83
  84         _enter("");
  85
  86         sp = rxrpc_skb(skb);
  87
  88         /* get a notification message to send to the server app */
  89         notification = alloc_skb(0, GFP_NOFS);
  90         if (!notification) {
  91                 _debug("no memory");
  92                 ret = -ENOMEM;
  93                 goto error_nofree;
  94         }
  95         rxrpc_new_skb(notification);
  96         notification->mark = RXRPC_SKB_MARK_NEW_CALL;
  97
  98         peer = rxrpc_get_peer(srx, GFP_NOIO);
  99         if (IS_ERR(peer)) {
 100                 _debug("no peer");
 101                 ret = -EBUSY;
 102                 goto error;
 103         }
 104
 105         trans = rxrpc_get_transport(local, peer, GFP_NOIO);
 106         rxrpc_put_peer(peer);
 107         if (IS_ERR(trans)) {
 108                 _debug("no trans");
 109                 ret = -EBUSY;
 110                 goto error;
 111         }
 112
 113         conn = rxrpc_incoming_connection(trans, &sp->hdr);
 114         rxrpc_put_transport(trans);
 115         if (IS_ERR(conn)) {
 116                 _debug("no conn");
 117                 ret = PTR_ERR(conn);
 118                 goto error;
 119         }
 120
 121         call = rxrpc_incoming_call(rx, conn, &sp->hdr);
 122         rxrpc_put_connection(conn);
 123         if (IS_ERR(call)) {
 124                 _debug("no call");
 125                 ret = PTR_ERR(call);
 126                 goto error;
 127         }
 128
 129         /* attach the call to the socket */
 130         read_lock_bh(&local->services_lock);
 131         if (rx->sk.sk_state == RXRPC_CLOSE)
 132                 goto invalid_service;
 133
 134         write_lock(&rx->call_lock);
 135         if (!test_and_set_bit(RXRPC_CALL_INIT_ACCEPT, &call->flags)) {
 136                 rxrpc_get_call(call);
 137
 138                 spin_lock(&call->conn->state_lock);
 139                 if (sp->hdr.securityIndex > 0 &&
 140                     call->conn->state == RXRPC_CONN_SERVER_UNSECURED) {
 141                         _debug("await conn sec");
 142                         list_add_tail(&call->accept_link, &rx->secureq);
 143                         call->conn->state = RXRPC_CONN_SERVER_CHALLENGING;
 144                         atomic_inc(&call->conn->usage);
 145                         set_bit(RXRPC_CONN_CHALLENGE, &call->conn->events);
 146                         rxrpc_queue_conn(call->conn);
 147                 } else {
 148                         _debug("conn ready");
 149                         call->state = RXRPC_CALL_SERVER_ACCEPTING;
 150                         list_add_tail(&call->accept_link, &rx->acceptq);
 151                         rxrpc_get_call(call);
 152                         nsp = rxrpc_skb(notification);
 153                         nsp->call = call;
 154
 155                         ASSERTCMP(atomic_read(&call->usage), >=, 3);
 156
 157                         _debug("notify");
 158                         spin_lock(&call->lock);
 159                         ret = rxrpc_queue_rcv_skb(call, notification, true,
 160                                                   false);
 161                         spin_unlock(&call->lock);
 162                         notification = NULL;
 163                         BUG_ON(ret < 0);
 164                 }
 165                 spin_unlock(&call->conn->state_lock);
 166
 167                 _debug("queued");
 168         }
 169         write_unlock(&rx->call_lock);
 170
 171         _debug("process");
 172         rxrpc_fast_process_packet(call, skb);
 173
 174         _debug("done");
 175         read_unlock_bh(&local->services_lock);
 176         rxrpc_free_skb(notification);
 177         rxrpc_put_call(call);
 178         _leave(" = 0");
 179         return 0;
 180
 181 invalid_service:
 182         _debug("invalid");
 183         read_unlock_bh(&local->services_lock);
 184
 185         read_lock_bh(&call->state_lock);
 186         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
 187             !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events)) {
 188                 rxrpc_get_call(call);
 189                 rxrpc_queue_call(call);
 190         }
 191         read_unlock_bh(&call->state_lock);
 192         rxrpc_put_call(call);
 193         ret = -ECONNREFUSED;
 194 error:
 195         rxrpc_free_skb(notification);
 196 error_nofree:
 197         _leave(" = %d", ret);
 198         return ret;
 199 }
 200
 201 /*
 202  * accept incoming calls that need peer, transport and/or connection setting up
 203  * - the packets we get are all incoming client DATA packets that have seq == 1
 204  */
 205 void rxrpc_accept_incoming_calls(struct work_struct *work)
 206 {
 207         struct rxrpc_local *local =
 208                 container_of(work, struct rxrpc_local, acceptor);
 209         struct rxrpc_skb_priv *sp;
 210         struct sockaddr_rxrpc srx;
 211         struct rxrpc_sock *rx;
 212         struct rxrpc_wire_header whdr;
 213         struct sk_buff *skb;
 214         int ret;
 215
 216         _enter("%d", local->debug_id);
 217
 218         read_lock_bh(&rxrpc_local_lock);
 219         if (atomic_read(&local->usage) > 0)
 220                 rxrpc_get_local(local);
 221         else
 222                 local = NULL;
 223         read_unlock_bh(&rxrpc_local_lock);
 224         if (!local) {
 225                 _leave(" [local dead]");
 226                 return;
 227         }
 228
 229 process_next_packet:
 230         skb = skb_dequeue(&local->accept_queue);
 231         if (!skb) {
 232                 rxrpc_put_local(local);
 233                 _leave("\n");
 234                 return;
 235         }
 236
 237         _net("incoming call skb %p", skb);
 238
 239         sp = rxrpc_skb(skb);
 240
 241         /* Set up a response packet header in case we need it */
 242         whdr.epoch      = htonl(sp->hdr.epoch);
 243         whdr.cid        = htonl(sp->hdr.cid);
 244         whdr.callNumber = htonl(sp->hdr.callNumber);
 245         whdr.seq        = htonl(sp->hdr.seq);
 246         whdr.serial     = 0;
 247         whdr.flags      = 0;
 248         whdr.type       = 0;
 249         whdr.userStatus = 0;
 250         whdr.securityIndex = sp->hdr.securityIndex;
 251         whdr._rsvd      = 0;
 252         whdr.serviceId  = htons(sp->hdr.serviceId);
 253
 254         /* determine the remote address */
 255         memset(&srx, 0, sizeof(srx));
 256         srx.srx_family = AF_RXRPC;
 257         srx.transport.family = local->srx.transport.family;
 258         srx.transport_type = local->srx.transport_type;
 259         switch (srx.transport.family) {
 260         case AF_INET:
 261                 srx.transport_len = sizeof(struct sockaddr_in);
 262                 srx.transport.sin.sin_port = udp_hdr(skb)->source;
 263                 srx.transport.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
 264                 break;
 265         default:
 266                 goto busy;
 267         }
 268
 269         /* get the socket providing the service */
 270         read_lock_bh(&local->services_lock);
 271         list_for_each_entry(rx, &local->services, listen_link) {
 272                 if (rx->srx.srx_service == sp->hdr.serviceId &&
 273                     rx->sk.sk_state != RXRPC_CLOSE)
 274                         goto found_service;
 275         }
 276         read_unlock_bh(&local->services_lock);
 277         goto invalid_service;
 278
 279 found_service:
 280         _debug("found service %hd", rx->srx.srx_service);
 281         if (sk_acceptq_is_full(&rx->sk))
 282                 goto backlog_full;
 283         sk_acceptq_added(&rx->sk);
 284         sock_hold(&rx->sk);
 285         read_unlock_bh(&local->services_lock);
 286
 287         ret = rxrpc_accept_incoming_call(local, rx, skb, &srx);
 288         if (ret < 0)
 289                 sk_acceptq_removed(&rx->sk);
 290         sock_put(&rx->sk);
 291         switch (ret) {
 292         case -ECONNRESET: /* old calls are ignored */
 293         case -ECONNABORTED: /* aborted calls are reaborted or ignored */
 294         case 0:
 295                 goto process_next_packet;
 296         case -ECONNREFUSED:
 297                 goto invalid_service;
 298         case -EBUSY:
 299                 goto busy;
 300         case -EKEYREJECTED:
 301                 goto security_mismatch;
 302         default:
 303                 BUG();
 304         }
 305
 306 backlog_full:
 307         read_unlock_bh(&local->services_lock);
 308 busy:
 309         rxrpc_busy(local, &srx, &whdr);
 310         rxrpc_free_skb(skb);
 311         goto process_next_packet;
 312
 313 invalid_service:
 314         skb->priority = RX_INVALID_OPERATION;
 315         rxrpc_reject_packet(local, skb);
 316         goto process_next_packet;
 317
 318         /* can't change connection security type mid-flow */
 319 security_mismatch:
 320         skb->priority = RX_PROTOCOL_ERROR;
 321         rxrpc_reject_packet(local, skb);
 322         goto process_next_packet;
 323 }
 324
 325 /*
 326  * handle acceptance of a call by userspace
 327  * - assign the user call ID to the call at the front of the queue
 328  */
 329 struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
 330                                      unsigned long user_call_ID)
 331 {
 332         struct rxrpc_call *call;
 333         struct rb_node *parent, **pp;
 334         int ret;
 335
 336         _enter(",%lx", user_call_ID);
 337
 338         ASSERT(!irqs_disabled());
 339
 340         write_lock(&rx->call_lock);
 341
 342         ret = -ENODATA;
 343         if (list_empty(&rx->acceptq))
 344                 goto out;
 345
 346         /* check the user ID isn't already in use */
 347         ret = -EBADSLT;
 348         pp = &rx->calls.rb_node;
 349         parent = NULL;
 350         while (*pp) {
 351                 parent = *pp;
 352                 call = rb_entry(parent, struct rxrpc_call, sock_node);
 353
 354                 if (user_call_ID < call->user_call_ID)
 355                         pp = &(*pp)->rb_left;
 356                 else if (user_call_ID > call->user_call_ID)
 357                         pp = &(*pp)->rb_right;
 358                 else
 359                         goto out;
 360         }
 361
 362         /* dequeue the first call and check it's still valid */
 363         call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
 364         list_del_init(&call->accept_link);
 365         sk_acceptq_removed(&rx->sk);
 366
 367         write_lock_bh(&call->state_lock);
 368         switch (call->state) {
 369         case RXRPC_CALL_SERVER_ACCEPTING:
 370                 call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
 371                 break;
 372         case RXRPC_CALL_REMOTELY_ABORTED:
 373         case RXRPC_CALL_LOCALLY_ABORTED:
 374                 ret = -ECONNABORTED;
 375                 goto out_release;
 376         case RXRPC_CALL_NETWORK_ERROR:
 377                 ret = call->conn->error;
 378                 goto out_release;
 379         case RXRPC_CALL_DEAD:
 380                 ret = -ETIME;
 381                 goto out_discard;
 382         default:
 383                 BUG();
 384         }
 385
 386         /* formalise the acceptance */
 387         call->user_call_ID = user_call_ID;
 388         rb_link_node(&call->sock_node, parent, pp);
 389         rb_insert_color(&call->sock_node, &rx->calls);
 390         if (test_and_set_bit(RXRPC_CALL_HAS_USERID, &call->flags))
 391                 BUG();
 392         if (test_and_set_bit(RXRPC_CALL_EV_ACCEPTED, &call->events))
 393                 BUG();
 394         rxrpc_queue_call(call);
 395
 396         rxrpc_get_call(call);
 397         write_unlock_bh(&call->state_lock);
 398         write_unlock(&rx->call_lock);
 399         _leave(" = %p{%d}", call, call->debug_id);
 400         return call;
 401
 402         /* if the call is already dying or dead, then we leave the socket's ref
 403          * on it to be released by rxrpc_dead_call_expired() as induced by
 404          * rxrpc_release_call() */
 405 out_release:
 406         _debug("release %p", call);
 407         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
 408             !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
 409                 rxrpc_queue_call(call);
 410 out_discard:
 411         write_unlock_bh(&call->state_lock);
 412         _debug("discard %p", call);
 413 out:
 414         write_unlock(&rx->call_lock);
 415         _leave(" = %d", ret);
 416         return ERR_PTR(ret);
 417 }
 418
 419 /*
 420  * Handle rejection of a call by userspace
 421  * - reject the call at the front of the queue
 422  */
 423 int rxrpc_reject_call(struct rxrpc_sock *rx)
 424 {
 425         struct rxrpc_call *call;
 426         int ret;
 427
 428         _enter("");
 429
 430         ASSERT(!irqs_disabled());
 431
 432         write_lock(&rx->call_lock);
 433
 434         ret = -ENODATA;
 435         if (list_empty(&rx->acceptq))
 436                 goto out;
 437
 438         /* dequeue the first call and check it's still valid */
 439         call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
 440         list_del_init(&call->accept_link);
 441         sk_acceptq_removed(&rx->sk);
 442
 443         write_lock_bh(&call->state_lock);
 444         switch (call->state) {
 445         case RXRPC_CALL_SERVER_ACCEPTING:
 446                 call->state = RXRPC_CALL_SERVER_BUSY;
 447                 if (test_and_set_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events))
 448                         rxrpc_queue_call(call);
 449                 ret = 0;
 450                 goto out_release;
 451         case RXRPC_CALL_REMOTELY_ABORTED:
 452         case RXRPC_CALL_LOCALLY_ABORTED:
 453                 ret = -ECONNABORTED;
 454                 goto out_release;
 455         case RXRPC_CALL_NETWORK_ERROR:
 456                 ret = call->conn->error;
 457                 goto out_release;
 458         case RXRPC_CALL_DEAD:
 459                 ret = -ETIME;
 460                 goto out_discard;
 461         default:
 462                 BUG();
 463         }
 464
 465         /* if the call is already dying or dead, then we leave the socket's ref
 466          * on it to be released by rxrpc_dead_call_expired() as induced by
 467          * rxrpc_release_call() */
 468 out_release:
 469         _debug("release %p", call);
 470         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
 471             !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
 472                 rxrpc_queue_call(call);
 473 out_discard:
 474         write_unlock_bh(&call->state_lock);
 475         _debug("discard %p", call);
 476 out:
 477         write_unlock(&rx->call_lock);
 478         _leave(" = %d", ret);
 479         return ret;
 480 }
 481
 482 /**
 483  * rxrpc_kernel_accept_call - Allow a kernel service to accept an incoming call
 484  * @sock: The socket on which the impending call is waiting
 485  * @user_call_ID: The tag to attach to the call
 486  *
 487  * Allow a kernel service to accept an incoming call, assuming the incoming
 488  * call is still valid.
 489  */
 490 struct rxrpc_call *rxrpc_kernel_accept_call(struct socket *sock,
 491                                             unsigned long user_call_ID)
 492 {
 493         struct rxrpc_call *call;
 494
 495         _enter(",%lx", user_call_ID);
 496         call = rxrpc_accept_call(rxrpc_sk(sock->sk), user_call_ID);
 497         _leave(" = %p", call);
 498         return call;
 499 }
 500 EXPORT_SYMBOL(rxrpc_kernel_accept_call);
 501
 502 /**
 503  * rxrpc_kernel_reject_call - Allow a kernel service to reject an incoming call
 504  * @sock: The socket on which the impending call is waiting
 505  *
 506  * Allow a kernel service to reject an incoming call with a BUSY message,
 507  * assuming the incoming call is still valid.
 508  */
 509 int rxrpc_kernel_reject_call(struct socket *sock)
 510 {
 511         int ret;
 512
 513         _enter("");
 514         ret = rxrpc_reject_call(rxrpc_sk(sock->sk));
 515         _leave(" = %d", ret);
 516         return ret;
 517 }
 518 EXPORT_SYMBOL(rxrpc_kernel_reject_call);