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