net/sctp/endpointola.c

   1 /* SCTP kernel reference Implementation
   2  * Copyright (c) 1999-2000 Cisco, Inc.
   3  * Copyright (c) 1999-2001 Motorola, Inc.
   4  * Copyright (c) 2001-2002 International Business Machines, Corp.
   5  * Copyright (c) 2001 Intel Corp.
   6  * Copyright (c) 2001 Nokia, Inc.
   7  * Copyright (c) 2001 La Monte H.P. Yarroll
   8  *
   9  * This file is part of the SCTP kernel reference Implementation
  10  *
  11  * This abstraction represents an SCTP endpoint.
  12  *
  13  * This file is part of the implementation of the add-IP extension,
  14  * based on <draft-ietf-tsvwg-addip-sctp-02.txt> June 29, 2001,
  15  * for the SCTP kernel reference Implementation.
  16  *
  17  * The SCTP reference implementation is free software;
  18  * you can redistribute it and/or modify it under the terms of
  19  * the GNU General Public License as published by
  20  * the Free Software Foundation; either version 2, or (at your option)
  21  * any later version.
  22  *
  23  * The SCTP reference implementation is distributed in the hope that it
  24  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
  25  *                 ************************
  26  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  27  * See the GNU General Public License for more details.
  28  *
  29  * You should have received a copy of the GNU General Public License
  30  * along with GNU CC; see the file COPYING.  If not, write to
  31  * the Free Software Foundation, 59 Temple Place - Suite 330,
  32  * Boston, MA 02111-1307, USA.
  33  *
  34  * Please send any bug reports or fixes you make to the
  35  * email address(es):
  36  *    lksctp developers <lksctp-developers@lists.sourceforge.net>
  37  *
  38  * Or submit a bug report through the following website:
  39  *    http://www.sf.net/projects/lksctp
  40  *
  41  * Written or modified by:
  42  *    La Monte H.P. Yarroll <piggy@acm.org>
  43  *    Karl Knutson <karl@athena.chicago.il.us>
  44  *    Jon Grimm <jgrimm@austin.ibm.com>
  45  *    Daisy Chang <daisyc@us.ibm.com>
  46  *    Dajiang Zhang <dajiang.zhang@nokia.com>
  47  *
  48  * Any bugs reported given to us we will try to fix... any fixes shared will
  49  * be incorporated into the next SCTP release.
  50  */
  51
  52 #include <linux/types.h>
  53 #include <linux/slab.h>
  54 #include <linux/in.h>
  55 #include <linux/random.h>       /* get_random_bytes() */
  56 #include <linux/crypto.h>
  57 #include <net/sock.h>
  58 #include <net/ipv6.h>
  59 #include <net/sctp/sctp.h>
  60 #include <net/sctp/sm.h>
  61
  62 /* Forward declarations for internal helpers. */
  63 static void sctp_endpoint_bh_rcv(struct work_struct *work);
  64
  65 /*
  66  * Initialize the base fields of the endpoint structure.
  67  */
  68 static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
  69                                                 struct sock *sk,
  70                                                 gfp_t gfp)
  71 {
  72         memset(ep, 0, sizeof(struct sctp_endpoint));
  73
  74         ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp);
  75         if (!ep->digest)
  76                 return NULL;
  77
  78         /* Initialize the base structure. */
  79         /* What type of endpoint are we?  */
  80         ep->base.type = SCTP_EP_TYPE_SOCKET;
  81
  82         /* Initialize the basic object fields. */
  83         atomic_set(&ep->base.refcnt, 1);
  84         ep->base.dead = 0;
  85         ep->base.malloced = 1;
  86
  87         /* Create an input queue.  */
  88         sctp_inq_init(&ep->base.inqueue);
  89
  90         /* Set its top-half handler */
  91         sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv);
  92
  93         /* Initialize the bind addr area */
  94         sctp_bind_addr_init(&ep->base.bind_addr, 0);
  95
  96         /* Remember who we are attached to.  */
  97         ep->base.sk = sk;
  98         sock_hold(ep->base.sk);
  99
 100         /* Create the lists of associations.  */
 101         INIT_LIST_HEAD(&ep->asocs);
 102
 103         /* Use SCTP specific send buffer space queues.  */
 104         ep->sndbuf_policy = sctp_sndbuf_policy;
 105         sk->sk_write_space = sctp_write_space;
 106         sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
 107
 108         /* Get the receive buffer policy for this endpoint */
 109         ep->rcvbuf_policy = sctp_rcvbuf_policy;
 110
 111         /* Initialize the secret key used with cookie. */
 112         get_random_bytes(&ep->secret_key[0], SCTP_SECRET_SIZE);
 113         ep->last_key = ep->current_key = 0;
 114         ep->key_changed_at = jiffies;
 115
 116         return ep;
 117 }
 118
 119 /* Create a sctp_endpoint with all that boring stuff initialized.
 120  * Returns NULL if there isn't enough memory.
 121  */
 122 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
 123 {
 124         struct sctp_endpoint *ep;
 125
 126         /* Build a local endpoint. */
 127         ep = t_new(struct sctp_endpoint, gfp);
 128         if (!ep)
 129                 goto fail;
 130         if (!sctp_endpoint_init(ep, sk, gfp))
 131                 goto fail_init;
 132         ep->base.malloced = 1;
 133         SCTP_DBG_OBJCNT_INC(ep);
 134         return ep;
 135
 136 fail_init:
 137         kfree(ep);
 138 fail:
 139         return NULL;
 140 }
 141
 142 /* Add an association to an endpoint.  */
 143 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
 144                             struct sctp_association *asoc)
 145 {
 146         struct sock *sk = ep->base.sk;
 147
 148         /* If this is a temporary association, don't bother
 149          * since we'll be removing it shortly and don't
 150          * want anyone to find it anyway.
 151          */
 152         if (asoc->temp)
 153                 return;
 154
 155         /* Now just add it to our list of asocs */
 156         list_add_tail(&asoc->asocs, &ep->asocs);
 157
 158         /* Increment the backlog value for a TCP-style listening socket. */
 159         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
 160                 sk->sk_ack_backlog++;
 161 }
 162
 163 /* Free the endpoint structure.  Delay cleanup until
 164  * all users have released their reference count on this structure.
 165  */
 166 void sctp_endpoint_free(struct sctp_endpoint *ep)
 167 {
 168         ep->base.dead = 1;
 169
 170         ep->base.sk->sk_state = SCTP_SS_CLOSED;
 171
 172         /* Unlink this endpoint, so we can't find it again! */
 173         sctp_unhash_endpoint(ep);
 174
 175         sctp_endpoint_put(ep);
 176 }
 177
 178 /* Final destructor for endpoint.  */
 179 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
 180 {
 181         SCTP_ASSERT(ep->base.dead, "Endpoint is not dead", return);
 182
 183         /* Free up the HMAC transform. */
 184         crypto_free_hash(sctp_sk(ep->base.sk)->hmac);
 185
 186         /* Free the digest buffer */
 187         kfree(ep->digest);
 188
 189         /* Cleanup. */
 190         sctp_inq_free(&ep->base.inqueue);
 191         sctp_bind_addr_free(&ep->base.bind_addr);
 192
 193         /* Remove and free the port */
 194         if (sctp_sk(ep->base.sk)->bind_hash)
 195                 sctp_put_port(ep->base.sk);
 196
 197         /* Give up our hold on the sock. */
 198         if (ep->base.sk)
 199                 sock_put(ep->base.sk);
 200
 201         /* Finally, free up our memory. */
 202         if (ep->base.malloced) {
 203                 kfree(ep);
 204                 SCTP_DBG_OBJCNT_DEC(ep);
 205         }
 206 }
 207
 208 /* Hold a reference to an endpoint. */
 209 void sctp_endpoint_hold(struct sctp_endpoint *ep)
 210 {
 211         atomic_inc(&ep->base.refcnt);
 212 }
 213
 214 /* Release a reference to an endpoint and clean up if there are
 215  * no more references.
 216  */
 217 void sctp_endpoint_put(struct sctp_endpoint *ep)
 218 {
 219         if (atomic_dec_and_test(&ep->base.refcnt))
 220                 sctp_endpoint_destroy(ep);
 221 }
 222
 223 /* Is this the endpoint we are looking for?  */
 224 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
 225                                                const union sctp_addr *laddr)
 226 {
 227         struct sctp_endpoint *retval = NULL;
 228
 229         if (htons(ep->base.bind_addr.port) == laddr->v4.sin_port) {
 230                 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
 231                                          sctp_sk(ep->base.sk)))
 232                         retval = ep;
 233         }
 234
 235         return retval;
 236 }
 237
 238 /* Find the association that goes with this chunk.
 239  * We do a linear search of the associations for this endpoint.
 240  * We return the matching transport address too.
 241  */
 242 static struct sctp_association *__sctp_endpoint_lookup_assoc(
 243         const struct sctp_endpoint *ep,
 244         const union sctp_addr *paddr,
 245         struct sctp_transport **transport)
 246 {
 247         int rport;
 248         struct sctp_association *asoc;
 249         struct list_head *pos;
 250
 251         rport = ntohs(paddr->v4.sin_port);
 252
 253         list_for_each(pos, &ep->asocs) {
 254                 asoc = list_entry(pos, struct sctp_association, asocs);
 255                 if (rport == asoc->peer.port) {
 256                         *transport = sctp_assoc_lookup_paddr(asoc, paddr);
 257
 258                         if (*transport)
 259                                 return asoc;
 260                 }
 261         }
 262
 263         *transport = NULL;
 264         return NULL;
 265 }
 266
 267 /* Lookup association on an endpoint based on a peer address.  BH-safe.  */
 268 struct sctp_association *sctp_endpoint_lookup_assoc(
 269         const struct sctp_endpoint *ep,
 270         const union sctp_addr *paddr,
 271         struct sctp_transport **transport)
 272 {
 273         struct sctp_association *asoc;
 274
 275         sctp_local_bh_disable();
 276         asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport);
 277         sctp_local_bh_enable();
 278
 279         return asoc;
 280 }
 281
 282 /* Look for any peeled off association from the endpoint that matches the
 283  * given peer address.
 284  */
 285 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
 286                                 const union sctp_addr *paddr)
 287 {
 288         struct sctp_sockaddr_entry *addr;
 289         struct sctp_bind_addr *bp;
 290
 291         bp = &ep->base.bind_addr;
 292         /* This function is called with the socket lock held,
 293          * so the address_list can not change.
 294          */
 295         list_for_each_entry(addr, &bp->address_list, list) {
 296                 if (sctp_has_association(&addr->a, paddr))
 297                         return 1;
 298         }
 299
 300         return 0;
 301 }
 302
 303 /* Do delayed input processing.  This is scheduled by sctp_rcv().
 304  * This may be called on BH or task time.
 305  */
 306 static void sctp_endpoint_bh_rcv(struct work_struct *work)
 307 {
 308         struct sctp_endpoint *ep =
 309                 container_of(work, struct sctp_endpoint,
 310                              base.inqueue.immediate);
 311         struct sctp_association *asoc;
 312         struct sock *sk;
 313         struct sctp_transport *transport;
 314         struct sctp_chunk *chunk;
 315         struct sctp_inq *inqueue;
 316         sctp_subtype_t subtype;
 317         sctp_state_t state;
 318         int error = 0;
 319
 320         if (ep->base.dead)
 321                 return;
 322
 323         asoc = NULL;
 324         inqueue = &ep->base.inqueue;
 325         sk = ep->base.sk;
 326
 327         while (NULL != (chunk = sctp_inq_pop(inqueue))) {
 328                 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
 329
 330                 /* We might have grown an association since last we
 331                  * looked, so try again.
 332                  *
 333                  * This happens when we've just processed our
 334                  * COOKIE-ECHO chunk.
 335                  */
 336                 if (NULL == chunk->asoc) {
 337                         asoc = sctp_endpoint_lookup_assoc(ep,
 338                                                           sctp_source(chunk),
 339                                                           &transport);
 340                         chunk->asoc = asoc;
 341                         chunk->transport = transport;
 342                 }
 343
 344                 state = asoc ? asoc->state : SCTP_STATE_CLOSED;
 345
 346                 /* Remember where the last DATA chunk came from so we
 347                  * know where to send the SACK.
 348                  */
 349                 if (asoc && sctp_chunk_is_data(chunk))
 350                         asoc->peer.last_data_from = chunk->transport;
 351                 else
 352                         SCTP_INC_STATS(SCTP_MIB_INCTRLCHUNKS);
 353
 354                 if (chunk->transport)
 355                         chunk->transport->last_time_heard = jiffies;
 356
 357                 error = sctp_do_sm(SCTP_EVENT_T_CHUNK, subtype, state,
 358                                    ep, asoc, chunk, GFP_ATOMIC);
 359
 360                 if (error && chunk)
 361                         chunk->pdiscard = 1;
 362
 363                 /* Check to see if the endpoint is freed in response to
 364                  * the incoming chunk. If so, get out of the while loop.
 365                  */
 366                 if (!sctp_sk(sk)->ep)
 367                         break;
 368         }
 369 }