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         rxrpc_release_call(rx, call);
 167         rxrpc_put_call(call, rxrpc_call_put);
 168         ret = -ECONNREFUSED;
 169 error:
 170         rxrpc_free_skb(notification);
 171 error_nofree:
 172         _leave(" = %d", ret);
 173         return ret;
 174 }
 175
 176 /*
 177  * accept incoming calls that need peer, transport and/or connection setting up
 178  * - the packets we get are all incoming client DATA packets that have seq == 1
 179  */
 180 void rxrpc_accept_incoming_calls(struct rxrpc_local *local)
 181 {
 182         struct rxrpc_skb_priv *sp;
 183         struct sockaddr_rxrpc srx;
 184         struct rxrpc_sock *rx;
 185         struct rxrpc_wire_header whdr;
 186         struct sk_buff *skb;
 187         int ret;
 188
 189         _enter("%d", local->debug_id);
 190
 191         skb = skb_dequeue(&local->accept_queue);
 192         if (!skb) {
 193                 _leave("\n");
 194                 return;
 195         }
 196
 197         _net("incoming call skb %p", skb);
 198
 199         rxrpc_see_skb(skb);
 200         sp = rxrpc_skb(skb);
 201
 202         /* Set up a response packet header in case we need it */
 203         whdr.epoch      = htonl(sp->hdr.epoch);
 204         whdr.cid        = htonl(sp->hdr.cid);
 205         whdr.callNumber = htonl(sp->hdr.callNumber);
 206         whdr.seq        = htonl(sp->hdr.seq);
 207         whdr.serial     = 0;
 208         whdr.flags      = 0;
 209         whdr.type       = 0;
 210         whdr.userStatus = 0;
 211         whdr.securityIndex = sp->hdr.securityIndex;
 212         whdr._rsvd      = 0;
 213         whdr.serviceId  = htons(sp->hdr.serviceId);
 214
 215         if (rxrpc_extract_addr_from_skb(&srx, skb) < 0)
 216                 goto drop;
 217
 218         /* get the socket providing the service */
 219         read_lock_bh(&local->services_lock);
 220         hlist_for_each_entry(rx, &local->services, listen_link) {
 221                 if (rx->srx.srx_service == sp->hdr.serviceId &&
 222                     rx->sk.sk_state != RXRPC_CLOSE)
 223                         goto found_service;
 224         }
 225         read_unlock_bh(&local->services_lock);
 226         goto invalid_service;
 227
 228 found_service:
 229         _debug("found service %hd", rx->srx.srx_service);
 230         if (sk_acceptq_is_full(&rx->sk))
 231                 goto backlog_full;
 232         sk_acceptq_added(&rx->sk);
 233         read_unlock_bh(&local->services_lock);
 234
 235         ret = rxrpc_accept_incoming_call(local, rx, skb, &srx);
 236         if (ret < 0)
 237                 sk_acceptq_removed(&rx->sk);
 238         switch (ret) {
 239         case -ECONNRESET: /* old calls are ignored */
 240         case -ECONNABORTED: /* aborted calls are reaborted or ignored */
 241         case 0:
 242                 return;
 243         case -ECONNREFUSED:
 244                 goto invalid_service;
 245         case -EBUSY:
 246                 goto busy;
 247         case -EKEYREJECTED:
 248                 goto security_mismatch;
 249         default:
 250                 BUG();
 251         }
 252
 253 backlog_full:
 254         read_unlock_bh(&local->services_lock);
 255 busy:
 256         rxrpc_busy(local, &srx, &whdr);
 257         rxrpc_free_skb(skb);
 258         return;
 259
 260 drop:
 261         rxrpc_free_skb(skb);
 262         return;
 263
 264 invalid_service:
 265         skb->priority = RX_INVALID_OPERATION;
 266         rxrpc_reject_packet(local, skb);
 267         return;
 268
 269         /* can't change connection security type mid-flow */
 270 security_mismatch:
 271         skb->priority = RX_PROTOCOL_ERROR;
 272         rxrpc_reject_packet(local, skb);
 273         return;
 274 }
 275
 276 /*
 277  * handle acceptance of a call by userspace
 278  * - assign the user call ID to the call at the front of the queue
 279  */
 280 struct rxrpc_call *rxrpc_accept_call(struct rxrpc_sock *rx,
 281                                      unsigned long user_call_ID,
 282                                      rxrpc_notify_rx_t notify_rx)
 283 {
 284         struct rxrpc_call *call;
 285         struct rb_node *parent, **pp;
 286         int ret;
 287
 288         _enter(",%lx", user_call_ID);
 289
 290         ASSERT(!irqs_disabled());
 291
 292         write_lock(&rx->call_lock);
 293
 294         ret = -ENODATA;
 295         if (list_empty(&rx->acceptq))
 296                 goto out;
 297
 298         /* check the user ID isn't already in use */
 299         ret = -EBADSLT;
 300         pp = &rx->calls.rb_node;
 301         parent = NULL;
 302         while (*pp) {
 303                 parent = *pp;
 304                 call = rb_entry(parent, struct rxrpc_call, sock_node);
 305
 306                 if (user_call_ID < call->user_call_ID)
 307                         pp = &(*pp)->rb_left;
 308                 else if (user_call_ID > call->user_call_ID)
 309                         pp = &(*pp)->rb_right;
 310                 else
 311                         goto out;
 312         }
 313
 314         /* dequeue the first call and check it's still valid */
 315         call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
 316         list_del_init(&call->accept_link);
 317         sk_acceptq_removed(&rx->sk);
 318         rxrpc_see_call(call);
 319
 320         write_lock_bh(&call->state_lock);
 321         switch (call->state) {
 322         case RXRPC_CALL_SERVER_ACCEPTING:
 323                 call->state = RXRPC_CALL_SERVER_RECV_REQUEST;
 324                 break;
 325         case RXRPC_CALL_COMPLETE:
 326                 ret = call->error;
 327                 goto out_release;
 328         default:
 329                 BUG();
 330         }
 331
 332         /* formalise the acceptance */
 333         rxrpc_get_call(call, rxrpc_call_got_userid);
 334         call->notify_rx = notify_rx;
 335         call->user_call_ID = user_call_ID;
 336         rb_link_node(&call->sock_node, parent, pp);
 337         rb_insert_color(&call->sock_node, &rx->calls);
 338         if (test_and_set_bit(RXRPC_CALL_HAS_USERID, &call->flags))
 339                 BUG();
 340         if (test_and_set_bit(RXRPC_CALL_EV_ACCEPTED, &call->events))
 341                 BUG();
 342
 343         write_unlock_bh(&call->state_lock);
 344         write_unlock(&rx->call_lock);
 345         rxrpc_queue_call(call);
 346         _leave(" = %p{%d}", call, call->debug_id);
 347         return call;
 348
 349 out_release:
 350         write_unlock_bh(&call->state_lock);
 351         write_unlock(&rx->call_lock);
 352         _debug("release %p", call);
 353         rxrpc_release_call(rx, call);
 354         _leave(" = %d", ret);
 355         return ERR_PTR(ret);
 356 out:
 357         write_unlock(&rx->call_lock);
 358         _leave(" = %d", ret);
 359         return ERR_PTR(ret);
 360 }
 361
 362 /*
 363  * Handle rejection of a call by userspace
 364  * - reject the call at the front of the queue
 365  */
 366 int rxrpc_reject_call(struct rxrpc_sock *rx)
 367 {
 368         struct rxrpc_call *call;
 369         int ret;
 370
 371         _enter("");
 372
 373         ASSERT(!irqs_disabled());
 374
 375         write_lock(&rx->call_lock);
 376
 377         ret = -ENODATA;
 378         if (list_empty(&rx->acceptq)) {
 379                 write_unlock(&rx->call_lock);
 380                 _leave(" = -ENODATA");
 381                 return -ENODATA;
 382         }
 383
 384         /* dequeue the first call and check it's still valid */
 385         call = list_entry(rx->acceptq.next, struct rxrpc_call, accept_link);
 386         list_del_init(&call->accept_link);
 387         sk_acceptq_removed(&rx->sk);
 388         rxrpc_see_call(call);
 389
 390         write_lock_bh(&call->state_lock);
 391         switch (call->state) {
 392         case RXRPC_CALL_SERVER_ACCEPTING:
 393                 __rxrpc_set_call_completion(call, RXRPC_CALL_SERVER_BUSY,
 394                                             0, ECONNABORTED);
 395                 if (test_and_set_bit(RXRPC_CALL_EV_REJECT_BUSY, &call->events))
 396                         rxrpc_queue_call(call);
 397                 ret = 0;
 398                 break;
 399         case RXRPC_CALL_COMPLETE:
 400                 ret = call->error;
 401                 break;
 402         default:
 403                 BUG();
 404         }
 405
 406         write_unlock_bh(&call->state_lock);
 407         write_unlock(&rx->call_lock);
 408         rxrpc_release_call(rx, call);
 409         _leave(" = %d", ret);
 410         return ret;
 411 }
 412
 413 /**
 414  * rxrpc_kernel_accept_call - Allow a kernel service to accept an incoming call
 415  * @sock: The socket on which the impending call is waiting
 416  * @user_call_ID: The tag to attach to the call
 417  * @notify_rx: Where to send notifications instead of socket queue
 418  *
 419  * Allow a kernel service to accept an incoming call, assuming the incoming
 420  * call is still valid.  The caller should immediately trigger their own
 421  * notification as there must be data waiting.
 422  */
 423 struct rxrpc_call *rxrpc_kernel_accept_call(struct socket *sock,
 424                                             unsigned long user_call_ID,
 425                                             rxrpc_notify_rx_t notify_rx)
 426 {
 427         struct rxrpc_call *call;
 428
 429         _enter(",%lx", user_call_ID);
 430         call = rxrpc_accept_call(rxrpc_sk(sock->sk), user_call_ID, notify_rx);
 431         _leave(" = %p", call);
 432         return call;
 433 }
 434 EXPORT_SYMBOL(rxrpc_kernel_accept_call);
 435
 436 /**
 437  * rxrpc_kernel_reject_call - Allow a kernel service to reject an incoming call
 438  * @sock: The socket on which the impending call is waiting
 439  *
 440  * Allow a kernel service to reject an incoming call with a BUSY message,
 441  * assuming the incoming call is still valid.
 442  */
 443 int rxrpc_kernel_reject_call(struct socket *sock)
 444 {
 445         int ret;
 446
 447         _enter("");
 448         ret = rxrpc_reject_call(rxrpc_sk(sock->sk));
 449         _leave(" = %d", ret);
 450         return ret;
 451 }
 452 EXPORT_SYMBOL(rxrpc_kernel_reject_call);