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         rwlock_init(&ep->base.addr_lock);
  96
  97         /* Remember who we are attached to.  */
  98         ep->base.sk = sk;
  99         sock_hold(ep->base.sk);
 100
 101         /* Create the lists of associations.  */
 102         INIT_LIST_HEAD(&ep->asocs);
 103
 104         /* Use SCTP specific send buffer space queues.  */
 105         ep->sndbuf_policy = sctp_sndbuf_policy;
 106         sk->sk_write_space = sctp_write_space;
 107         sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
 108
 109         /* Get the receive buffer policy for this endpoint */
 110         ep->rcvbuf_policy = sctp_rcvbuf_policy;
 111
 112         /* Initialize the secret key used with cookie. */
 113         get_random_bytes(&ep->secret_key[0], SCTP_SECRET_SIZE);
 114         ep->last_key = ep->current_key = 0;
 115         ep->key_changed_at = jiffies;
 116
 117         return ep;
 118 }
 119
 120 /* Create a sctp_endpoint with all that boring stuff initialized.
 121  * Returns NULL if there isn't enough memory.
 122  */
 123 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
 124 {
 125         struct sctp_endpoint *ep;
 126
 127         /* Build a local endpoint. */
 128         ep = t_new(struct sctp_endpoint, gfp);
 129         if (!ep)
 130                 goto fail;
 131         if (!sctp_endpoint_init(ep, sk, gfp))
 132                 goto fail_init;
 133         ep->base.malloced = 1;
 134         SCTP_DBG_OBJCNT_INC(ep);
 135         return ep;
 136
 137 fail_init:
 138         kfree(ep);
 139 fail:
 140         return NULL;
 141 }
 142
 143 /* Add an association to an endpoint.  */
 144 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
 145                             struct sctp_association *asoc)
 146 {
 147         struct sock *sk = ep->base.sk;
 148
 149         /* If this is a temporary association, don't bother
 150          * since we'll be removing it shortly and don't
 151          * want anyone to find it anyway.
 152          */
 153         if (asoc->temp)
 154                 return;
 155
 156         /* Now just add it to our list of asocs */
 157         list_add_tail(&asoc->asocs, &ep->asocs);
 158
 159         /* Increment the backlog value for a TCP-style listening socket. */
 160         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
 161                 sk->sk_ack_backlog++;
 162 }
 163
 164 /* Free the endpoint structure.  Delay cleanup until
 165  * all users have released their reference count on this structure.
 166  */
 167 void sctp_endpoint_free(struct sctp_endpoint *ep)
 168 {
 169         ep->base.dead = 1;
 170
 171         ep->base.sk->sk_state = SCTP_SS_CLOSED;
 172
 173         /* Unlink this endpoint, so we can't find it again! */
 174         sctp_unhash_endpoint(ep);
 175
 176         sctp_endpoint_put(ep);
 177 }
 178
 179 /* Final destructor for endpoint.  */
 180 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
 181 {
 182         SCTP_ASSERT(ep->base.dead, "Endpoint is not dead", return);
 183
 184         /* Free up the HMAC transform. */
 185         crypto_free_hash(sctp_sk(ep->base.sk)->hmac);
 186
 187         /* Free the digest buffer */
 188         kfree(ep->digest);
 189
 190         /* Cleanup. */
 191         sctp_inq_free(&ep->base.inqueue);
 192         sctp_bind_addr_free(&ep->base.bind_addr);
 193
 194         /* Remove and free the port */
 195         if (sctp_sk(ep->base.sk)->bind_hash)
 196                 sctp_put_port(ep->base.sk);
 197
 198         /* Give up our hold on the sock. */
 199         if (ep->base.sk)
 200                 sock_put(ep->base.sk);
 201
 202         /* Finally, free up our memory. */
 203         if (ep->base.malloced) {
 204                 kfree(ep);
 205                 SCTP_DBG_OBJCNT_DEC(ep);
 206         }
 207 }
 208
 209 /* Hold a reference to an endpoint. */
 210 void sctp_endpoint_hold(struct sctp_endpoint *ep)
 211 {
 212         atomic_inc(&ep->base.refcnt);
 213 }
 214
 215 /* Release a reference to an endpoint and clean up if there are
 216  * no more references.
 217  */
 218 void sctp_endpoint_put(struct sctp_endpoint *ep)
 219 {
 220         if (atomic_dec_and_test(&ep->base.refcnt))
 221                 sctp_endpoint_destroy(ep);
 222 }
 223
 224 /* Is this the endpoint we are looking for?  */
 225 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
 226                                                const union sctp_addr *laddr)
 227 {
 228         struct sctp_endpoint *retval;
 229
 230         sctp_read_lock(&ep->base.addr_lock);
 231         if (htons(ep->base.bind_addr.port) == laddr->v4.sin_port) {
 232                 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
 233                                          sctp_sk(ep->base.sk))) {
 234                         retval = ep;
 235                         goto out;
 236                 }
 237         }
 238
 239         retval = NULL;
 240
 241 out:
 242         sctp_read_unlock(&ep->base.addr_lock);
 243         return retval;
 244 }
 245
 246 /* Find the association that goes with this chunk.
 247  * We do a linear search of the associations for this endpoint.
 248  * We return the matching transport address too.
 249  */
 250 static struct sctp_association *__sctp_endpoint_lookup_assoc(
 251         const struct sctp_endpoint *ep,
 252         const union sctp_addr *paddr,
 253         struct sctp_transport **transport)
 254 {
 255         int rport;
 256         struct sctp_association *asoc;
 257         struct list_head *pos;
 258
 259         rport = ntohs(paddr->v4.sin_port);
 260
 261         list_for_each(pos, &ep->asocs) {
 262                 asoc = list_entry(pos, struct sctp_association, asocs);
 263                 if (rport == asoc->peer.port) {
 264                         sctp_read_lock(&asoc->base.addr_lock);
 265                         *transport = sctp_assoc_lookup_paddr(asoc, paddr);
 266                         sctp_read_unlock(&asoc->base.addr_lock);
 267
 268                         if (*transport)
 269                                 return asoc;
 270                 }
 271         }
 272
 273         *transport = NULL;
 274         return NULL;
 275 }
 276
 277 /* Lookup association on an endpoint based on a peer address.  BH-safe.  */
 278 struct sctp_association *sctp_endpoint_lookup_assoc(
 279         const struct sctp_endpoint *ep,
 280         const union sctp_addr *paddr,
 281         struct sctp_transport **transport)
 282 {
 283         struct sctp_association *asoc;
 284
 285         sctp_local_bh_disable();
 286         asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport);
 287         sctp_local_bh_enable();
 288
 289         return asoc;
 290 }
 291
 292 /* Look for any peeled off association from the endpoint that matches the
 293  * given peer address.
 294  */
 295 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
 296                                 const union sctp_addr *paddr)
 297 {
 298         struct list_head *pos;
 299         struct sctp_sockaddr_entry *addr;
 300         struct sctp_bind_addr *bp;
 301
 302         sctp_read_lock(&ep->base.addr_lock);
 303         bp = &ep->base.bind_addr;
 304         list_for_each(pos, &bp->address_list) {
 305                 addr = list_entry(pos, struct sctp_sockaddr_entry, list);
 306                 if (sctp_has_association(&addr->a, paddr)) {
 307                         sctp_read_unlock(&ep->base.addr_lock);
 308                         return 1;
 309                 }
 310         }
 311         sctp_read_unlock(&ep->base.addr_lock);
 312
 313         return 0;
 314 }
 315
 316 /* Do delayed input processing.  This is scheduled by sctp_rcv().
 317  * This may be called on BH or task time.
 318  */
 319 static void sctp_endpoint_bh_rcv(struct work_struct *work)
 320 {
 321         struct sctp_endpoint *ep =
 322                 container_of(work, struct sctp_endpoint,
 323                              base.inqueue.immediate);
 324         struct sctp_association *asoc;
 325         struct sock *sk;
 326         struct sctp_transport *transport;
 327         struct sctp_chunk *chunk;
 328         struct sctp_inq *inqueue;
 329         sctp_subtype_t subtype;
 330         sctp_state_t state;
 331         int error = 0;
 332
 333         if (ep->base.dead)
 334                 return;
 335
 336         asoc = NULL;
 337         inqueue = &ep->base.inqueue;
 338         sk = ep->base.sk;
 339
 340         while (NULL != (chunk = sctp_inq_pop(inqueue))) {
 341                 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
 342
 343                 /* We might have grown an association since last we
 344                  * looked, so try again.
 345                  *
 346                  * This happens when we've just processed our
 347                  * COOKIE-ECHO chunk.
 348                  */
 349                 if (NULL == chunk->asoc) {
 350                         asoc = sctp_endpoint_lookup_assoc(ep,
 351                                                           sctp_source(chunk),
 352                                                           &transport);
 353                         chunk->asoc = asoc;
 354                         chunk->transport = transport;
 355                 }
 356
 357                 state = asoc ? asoc->state : SCTP_STATE_CLOSED;
 358
 359                 /* Remember where the last DATA chunk came from so we
 360                  * know where to send the SACK.
 361                  */
 362                 if (asoc && sctp_chunk_is_data(chunk))
 363                         asoc->peer.last_data_from = chunk->transport;
 364                 else
 365                         SCTP_INC_STATS(SCTP_MIB_INCTRLCHUNKS);
 366
 367                 if (chunk->transport)
 368                         chunk->transport->last_time_heard = jiffies;
 369
 370                 error = sctp_do_sm(SCTP_EVENT_T_CHUNK, subtype, state,
 371                                    ep, asoc, chunk, GFP_ATOMIC);
 372
 373                 if (error && chunk)
 374                         chunk->pdiscard = 1;
 375
 376                 /* Check to see if the endpoint is freed in response to
 377                  * the incoming chunk. If so, get out of the while loop.
 378                  */
 379                 if (!sctp_sk(sk)->ep)
 380                         break;
 381         }
 382 }