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