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