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                         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);
 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);
 170                 rxrpc_queue_call(call);
 171         }
 172         read_unlock_bh(&call->state_lock);
 173         rxrpc_put_call(call);
 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         sp = rxrpc_skb(skb);
 206
 207         /* Set up a response packet header in case we need it */
 208         whdr.epoch      = htonl(sp->hdr.epoch);
 209         whdr.cid        = htonl(sp->hdr.cid);
 210         whdr.callNumber = htonl(sp->hdr.callNumber);
 211         whdr.seq        = htonl(sp->hdr.seq);
 212         whdr.serial     = 0;
 213         whdr.flags      = 0;
 214         whdr.type       = 0;
 215         whdr.userStatus = 0;
 216         whdr.securityIndex = sp->hdr.securityIndex;
 217         whdr._rsvd      = 0;
 218         whdr.serviceId  = htons(sp->hdr.serviceId);
 219
 220         if (rxrpc_extract_addr_from_skb(&srx, skb) < 0)
 221                 goto drop;
 222
 223         /* get the socket providing the service */
 224         read_lock_bh(&local->services_lock);
 225         list_for_each_entry(rx, &local->services, listen_link) {
 226                 if (rx->srx.srx_service == sp->hdr.serviceId &&
 227                     rx->sk.sk_state != RXRPC_CLOSE)
 228                         goto found_service;
 229         }
 230         read_unlock_bh(&local->services_lock);
 231         goto invalid_service;
 232
 233 found_service:
 234         _debug("found service %hd", rx->srx.srx_service);
 235         if (sk_acceptq_is_full(&rx->sk))
 236                 goto backlog_full;
 237         sk_acceptq_added(&rx->sk);
 238         sock_hold(&rx->sk);
 239         read_unlock_bh(&local->services_lock);
 240
 241         ret = rxrpc_accept_incoming_call(local, rx, skb, &srx);
 242         if (ret < 0)
 243                 sk_acceptq_removed(&rx->sk);
 244         sock_put(&rx->sk);
 245         switch (ret) {
 246         case -ECONNRESET: /* old calls are ignored */
 247         case -ECONNABORTED: /* aborted calls are reaborted or ignored */
 248         case 0:
 249                 return;
 250         case -ECONNREFUSED:
 251                 goto invalid_service;
 252         case -EBUSY:
 253                 goto busy;
 254         case -EKEYREJECTED:
 255                 goto security_mismatch;
 256         default:
 257                 BUG();
 258         }
 259
 260 backlog_full:
 261         read_unlock_bh(&local->services_lock);
 262 busy:
 263         rxrpc_busy(local, &srx, &whdr);
 264         rxrpc_free_skb(skb);
 265         return;
 266
 267 drop:
 268         rxrpc_free_skb(skb);
 269         return;
 270
 271 invalid_service:
 272         skb->priority = RX_INVALID_OPERATION;
 273         rxrpc_reject_packet(local, skb);
 274         return;
 275
 276         /* can't change connection security type mid-flow */
 277 security_mismatch:
 278         skb->priority = RX_PROTOCOL_ERROR;
 279         rxrpc_reject_packet(local, skb);
 280         return;
 281 }
 282
 283 /*
 284  * handle acceptance of a call by userspace
 285  * - assign the user call ID to the call at the front of the queue
 286  */
 287 struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
 288                                      unsigned long user_call_ID)
 289 {
 290         struct rxrpc_call *call;
 291         struct rb_node *parent, **pp;
 292         int ret;
 293
 294         _enter(",%lx", user_call_ID);
 295
 296         ASSERT(!irqs_disabled());
 297
 298         write_lock(&rx->call_lock);
 299
 300         ret = -ENODATA;
 301         if (list_empty(&rx->acceptq))
 302                 goto out;
 303
 304         /* check the user ID isn't already in use */
 305         ret = -EBADSLT;
 306         pp = &rx->calls.rb_node;
 307         parent = NULL;
 308         while (*pp) {
 309                 parent = *pp;
 310                 call = rb_entry(parent, struct rxrpc_call, sock_node);
 311
 312                 if (user_call_ID < call->user_call_ID)
 313                         pp = &(*pp)->rb_left;
 314                 else if (user_call_ID > call->user_call_ID)
 315                         pp = &(*pp)->rb_right;
 316                 else
 317                         goto out;
 318         }
 319
 320         /* dequeue the first call and check it's still valid */
 321         call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
 322         list_del_init(&call->accept_link);
 323         sk_acceptq_removed(&rx->sk);
 324
 325         write_lock_bh(&call->state_lock);
 326         switch (call->state) {
 327         case RXRPC_CALL_SERVER_ACCEPTING:
 328                 call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
 329                 break;
 330         case RXRPC_CALL_REMOTELY_ABORTED:
 331         case RXRPC_CALL_LOCALLY_ABORTED:
 332                 ret = -ECONNABORTED;
 333                 goto out_release;
 334         case RXRPC_CALL_NETWORK_ERROR:
 335                 ret = call->conn->error;
 336                 goto out_release;
 337         case RXRPC_CALL_DEAD:
 338                 ret = -ETIME;
 339                 goto out_discard;
 340         default:
 341                 BUG();
 342         }
 343
 344         /* formalise the acceptance */
 345         call->user_call_ID = user_call_ID;
 346         rb_link_node(&call->sock_node, parent, pp);
 347         rb_insert_color(&call->sock_node, &rx->calls);
 348         if (test_and_set_bit(RXRPC_CALL_HAS_USERID, &call->flags))
 349                 BUG();
 350         if (test_and_set_bit(RXRPC_CALL_EV_ACCEPTED, &call->events))
 351                 BUG();
 352         rxrpc_queue_call(call);
 353
 354         rxrpc_get_call(call);
 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
 401         write_lock_bh(&call->state_lock);
 402         switch (call->state) {
 403         case RXRPC_CALL_SERVER_ACCEPTING:
 404                 call->state = RXRPC_CALL_SERVER_BUSY;
 405                 if (test_and_set_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events))
 406                         rxrpc_queue_call(call);
 407                 ret = 0;
 408                 goto out_release;
 409         case RXRPC_CALL_REMOTELY_ABORTED:
 410         case RXRPC_CALL_LOCALLY_ABORTED:
 411                 ret = -ECONNABORTED;
 412                 goto out_release;
 413         case RXRPC_CALL_NETWORK_ERROR:
 414                 ret = call->conn->error;
 415                 goto out_release;
 416         case RXRPC_CALL_DEAD:
 417                 ret = -ETIME;
 418                 goto out_discard;
 419         default:
 420                 BUG();
 421         }
 422
 423         /* if the call is already dying or dead, then we leave the socket's ref
 424          * on it to be released by rxrpc_dead_call_expired() as induced by
 425          * rxrpc_release_call() */
 426 out_release:
 427         _debug("release %p", call);
 428         if (!test_bit(RXRPC_CALL_RELEASED, &call->flags) &&
 429             !test_and_set_bit(RXRPC_CALL_EV_RELEASE, &call->events))
 430                 rxrpc_queue_call(call);
 431 out_discard:
 432         write_unlock_bh(&call->state_lock);
 433         _debug("discard %p", call);
 434 out:
 435         write_unlock(&rx->call_lock);
 436         _leave(" = %d", ret);
 437         return ret;
 438 }
 439
 440 /**
 441  * rxrpc_kernel_accept_call - Allow a kernel service to accept an incoming call
 442  * @sock: The socket on which the impending call is waiting
 443  * @user_call_ID: The tag to attach to the call
 444  *
 445  * Allow a kernel service to accept an incoming call, assuming the incoming
 446  * call is still valid.
 447  */
 448 struct rxrpc_call *rxrpc_kernel_accept_call(struct socket *sock,
 449                                             unsigned long user_call_ID)
 450 {
 451         struct rxrpc_call *call;
 452
 453         _enter(",%lx", user_call_ID);
 454         call = rxrpc_accept_call(rxrpc_sk(sock->sk), user_call_ID);
 455         _leave(" = %p", call);
 456         return call;
 457 }
 458 EXPORT_SYMBOL(rxrpc_kernel_accept_call);
 459
 460 /**
 461  * rxrpc_kernel_reject_call - Allow a kernel service to reject an incoming call
 462  * @sock: The socket on which the impending call is waiting
 463  *
 464  * Allow a kernel service to reject an incoming call with a BUSY message,
 465  * assuming the incoming call is still valid.
 466  */
 467 int rxrpc_kernel_reject_call(struct socket *sock)
 468 {
 469         int ret;
 470
 471         _enter("");
 472         ret = rxrpc_reject_call(rxrpc_sk(sock->sk));
 473         _leave(" = %d", ret);
 474         return ret;
 475 }
 476 EXPORT_SYMBOL(rxrpc_kernel_reject_call);