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_lookup_peer(local, srx, GFP_NOIO);
  99         if (!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 rxrpc_local *local)
 206 {
 207         struct rxrpc_skb_priv *sp;
 208         struct sockaddr_rxrpc srx;
 209         struct rxrpc_sock *rx;
 210         struct rxrpc_wire_header whdr;
 211         struct sk_buff *skb;
 212         int ret;
 213
 214         _enter("%d", local->debug_id);
 215
 216         skb = skb_dequeue(&local->accept_queue);
 217         if (!skb) {
 218                 _leave("\n");
 219                 return;
 220         }
 221
 222         _net("incoming call skb %p", skb);
 223
 224         sp = rxrpc_skb(skb);
 225
 226         /* Set up a response packet header in case we need it */
 227         whdr.epoch      = htonl(sp->hdr.epoch);
 228         whdr.cid        = htonl(sp->hdr.cid);
 229         whdr.callNumber = htonl(sp->hdr.callNumber);
 230         whdr.seq        = htonl(sp->hdr.seq);
 231         whdr.serial     = 0;
 232         whdr.flags      = 0;
 233         whdr.type       = 0;
 234         whdr.userStatus = 0;
 235         whdr.securityIndex = sp->hdr.securityIndex;
 236         whdr._rsvd      = 0;
 237         whdr.serviceId  = htons(sp->hdr.serviceId);
 238
 239         /* determine the remote address */
 240         memset(&srx, 0, sizeof(srx));
 241         srx.srx_family = AF_RXRPC;
 242         srx.transport.family = local->srx.transport.family;
 243         srx.transport_type = local->srx.transport_type;
 244         switch (srx.transport.family) {
 245         case AF_INET:
 246                 srx.transport_len = sizeof(struct sockaddr_in);
 247                 srx.transport.sin.sin_port = udp_hdr(skb)->source;
 248                 srx.transport.sin.sin_addr.s_addr = ip_hdr(skb)->saddr;
 249                 break;
 250         default:
 251                 goto busy;
 252         }
 253
 254         /* get the socket providing the service */
 255         read_lock_bh(&local->services_lock);
 256         list_for_each_entry(rx, &local->services, listen_link) {
 257                 if (rx->srx.srx_service == sp->hdr.serviceId &&
 258                     rx->sk.sk_state != RXRPC_CLOSE)
 259                         goto found_service;
 260         }
 261         read_unlock_bh(&local->services_lock);
 262         goto invalid_service;
 263
 264 found_service:
 265         _debug("found service %hd", rx->srx.srx_service);
 266         if (sk_acceptq_is_full(&rx->sk))
 267                 goto backlog_full;
 268         sk_acceptq_added(&rx->sk);
 269         sock_hold(&rx->sk);
 270         read_unlock_bh(&local->services_lock);
 271
 272         ret = rxrpc_accept_incoming_call(local, rx, skb, &srx);
 273         if (ret < 0)
 274                 sk_acceptq_removed(&rx->sk);
 275         sock_put(&rx->sk);
 276         switch (ret) {
 277         case -ECONNRESET: /* old calls are ignored */
 278         case -ECONNABORTED: /* aborted calls are reaborted or ignored */
 279         case 0:
 280                 return;
 281         case -ECONNREFUSED:
 282                 goto invalid_service;
 283         case -EBUSY:
 284                 goto busy;
 285         case -EKEYREJECTED:
 286                 goto security_mismatch;
 287         default:
 288                 BUG();
 289         }
 290
 291 backlog_full:
 292         read_unlock_bh(&local->services_lock);
 293 busy:
 294         rxrpc_busy(local, &srx, &whdr);
 295         rxrpc_free_skb(skb);
 296         return;
 297
 298 invalid_service:
 299         skb->priority = RX_INVALID_OPERATION;
 300         rxrpc_reject_packet(local, skb);
 301         return;
 302
 303         /* can't change connection security type mid-flow */
 304 security_mismatch:
 305         skb->priority = RX_PROTOCOL_ERROR;
 306         rxrpc_reject_packet(local, skb);
 307         return;
 308 }
 309
 310 /*
 311  * handle acceptance of a call by userspace
 312  * - assign the user call ID to the call at the front of the queue
 313  */
 314 struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
 315                                      unsigned long user_call_ID)
 316 {
 317         struct rxrpc_call *call;
 318         struct rb_node *parent, **pp;
 319         int ret;
 320
 321         _enter(",%lx", user_call_ID);
 322
 323         ASSERT(!irqs_disabled());
 324
 325         write_lock(&rx->call_lock);
 326
 327         ret = -ENODATA;
 328         if (list_empty(&rx->acceptq))
 329                 goto out;
 330
 331         /* check the user ID isn't already in use */
 332         ret = -EBADSLT;
 333         pp = &rx->calls.rb_node;
 334         parent = NULL;
 335         while (*pp) {
 336                 parent = *pp;
 337                 call = rb_entry(parent, struct rxrpc_call, sock_node);
 338
 339                 if (user_call_ID < call->user_call_ID)
 340                         pp = &(*pp)->rb_left;
 341                 else if (user_call_ID > call->user_call_ID)
 342                         pp = &(*pp)->rb_right;
 343                 else
 344                         goto out;
 345         }
 346
 347         /* dequeue the first call and check it's still valid */
 348         call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
 349         list_del_init(&call->accept_link);
 350         sk_acceptq_removed(&rx->sk);
 351
 352         write_lock_bh(&call->state_lock);
 353         switch (call->state) {
 354         case RXRPC_CALL_SERVER_ACCEPTING:
 355                 call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
 356                 break;
 357         case RXRPC_CALL_REMOTELY_ABORTED:
 358         case RXRPC_CALL_LOCALLY_ABORTED:
 359                 ret = -ECONNABORTED;
 360                 goto out_release;
 361         case RXRPC_CALL_NETWORK_ERROR:
 362                 ret = call->conn->error;
 363                 goto out_release;
 364         case RXRPC_CALL_DEAD:
 365                 ret = -ETIME;
 366                 goto out_discard;
 367         default:
 368                 BUG();
 369         }
 370
 371         /* formalise the acceptance */
 372         call->user_call_ID = user_call_ID;
 373         rb_link_node(&call->sock_node, parent, pp);
 374         rb_insert_color(&call->sock_node, &rx->calls);
 375         if (test_and_set_bit(RXRPC_CALL_HAS_USERID, &call->flags))
 376                 BUG();
 377         if (test_and_set_bit(RXRPC_CALL_EV_ACCEPTED, &call->events))
 378                 BUG();
 379         rxrpc_queue_call(call);
 380
 381         rxrpc_get_call(call);
 382         write_unlock_bh(&call->state_lock);
 383         write_unlock(&rx->call_lock);
 384         _leave(" = %p{%d}", call, call->debug_id);
 385         return call;
 386
 387         /* if the call is already dying or dead, then we leave the socket's ref
 388          * on it to be released by rxrpc_dead_call_expired() as induced by
 389          * rxrpc_release_call() */
 390 out_release:
 391         _debug("release %p", call);
 392         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
 393             !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
 394                 rxrpc_queue_call(call);
 395 out_discard:
 396         write_unlock_bh(&call->state_lock);
 397         _debug("discard %p", call);
 398 out:
 399         write_unlock(&rx->call_lock);
 400         _leave(" = %d", ret);
 401         return ERR_PTR(ret);
 402 }
 403
 404 /*
 405  * Handle rejection of a call by userspace
 406  * - reject the call at the front of the queue
 407  */
 408 int rxrpc_reject_call(struct rxrpc_sock *rx)
 409 {
 410         struct rxrpc_call *call;
 411         int ret;
 412
 413         _enter("");
 414
 415         ASSERT(!irqs_disabled());
 416
 417         write_lock(&rx->call_lock);
 418
 419         ret = -ENODATA;
 420         if (list_empty(&rx->acceptq))
 421                 goto out;
 422
 423         /* dequeue the first call and check it's still valid */
 424         call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
 425         list_del_init(&call->accept_link);
 426         sk_acceptq_removed(&rx->sk);
 427
 428         write_lock_bh(&call->state_lock);
 429         switch (call->state) {
 430         case RXRPC_CALL_SERVER_ACCEPTING:
 431                 call->state = RXRPC_CALL_SERVER_BUSY;
 432                 if (test_and_set_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events))
 433                         rxrpc_queue_call(call);
 434                 ret = 0;
 435                 goto out_release;
 436         case RXRPC_CALL_REMOTELY_ABORTED:
 437         case RXRPC_CALL_LOCALLY_ABORTED:
 438                 ret = -ECONNABORTED;
 439                 goto out_release;
 440         case RXRPC_CALL_NETWORK_ERROR:
 441                 ret = call->conn->error;
 442                 goto out_release;
 443         case RXRPC_CALL_DEAD:
 444                 ret = -ETIME;
 445                 goto out_discard;
 446         default:
 447                 BUG();
 448         }
 449
 450         /* if the call is already dying or dead, then we leave the socket's ref
 451          * on it to be released by rxrpc_dead_call_expired() as induced by
 452          * rxrpc_release_call() */
 453 out_release:
 454         _debug("release %p", call);
 455         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
 456             !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
 457                 rxrpc_queue_call(call);
 458 out_discard:
 459         write_unlock_bh(&call->state_lock);
 460         _debug("discard %p", call);
 461 out:
 462         write_unlock(&rx->call_lock);
 463         _leave(" = %d", ret);
 464         return ret;
 465 }
 466
 467 /**
 468  * rxrpc_kernel_accept_call - Allow a kernel service to accept an incoming call
 469  * @sock: The socket on which the impending call is waiting
 470  * @user_call_ID: The tag to attach to the call
 471  *
 472  * Allow a kernel service to accept an incoming call, assuming the incoming
 473  * call is still valid.
 474  */
 475 struct rxrpc_call *rxrpc_kernel_accept_call(struct socket *sock,
 476                                             unsigned long user_call_ID)
 477 {
 478         struct rxrpc_call *call;
 479
 480         _enter(",%lx", user_call_ID);
 481         call = rxrpc_accept_call(rxrpc_sk(sock->sk), user_call_ID);
 482         _leave(" = %p", call);
 483         return call;
 484 }
 485 EXPORT_SYMBOL(rxrpc_kernel_accept_call);
 486
 487 /**
 488  * rxrpc_kernel_reject_call - Allow a kernel service to reject an incoming call
 489  * @sock: The socket on which the impending call is waiting
 490  *
 491  * Allow a kernel service to reject an incoming call with a BUSY message,
 492  * assuming the incoming call is still valid.
 493  */
 494 int rxrpc_kernel_reject_call(struct socket *sock)
 495 {
 496         int ret;
 497
 498         _enter("");
 499         ret = rxrpc_reject_call(rxrpc_sk(sock->sk));
 500         _leave(" = %d", ret);
 501         return ret;
 502 }
 503 EXPORT_SYMBOL(rxrpc_kernel_reject_call);