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/sched.h>
  54 #include <linux/slab.h>
  55 #include <linux/in.h>
  56 #include <linux/random.h>       /* get_random_bytes() */
  57 #include <linux/crypto.h>
  58 #include <net/sock.h>
  59 #include <net/ipv6.h>
  60 #include <net/sctp/sctp.h>
  61 #include <net/sctp/sm.h>
  62
  63 /* Forward declarations for internal helpers. */
  64 static void sctp_endpoint_bh_rcv(struct sctp_endpoint *ep);
  65
  66 /*
  67  * Initialize the base fields of the endpoint structure.
  68  */
  69 static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
  70                                                 struct sock *sk,
  71                                                 gfp_t gfp)
  72 {
  73         memset(ep, 0, sizeof(struct sctp_endpoint));
  74
  75         ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp);
  76         if (!ep->digest)
  77                 return NULL;
  78
  79         /* Initialize the base structure. */
  80         /* What type of endpoint are we?  */
  81         ep->base.type = SCTP_EP_TYPE_SOCKET;
  82
  83         /* Initialize the basic object fields. */
  84         atomic_set(&ep->base.refcnt, 1);
  85         ep->base.dead = 0;
  86         ep->base.malloced = 1;
  87
  88         /* Create an input queue.  */
  89         sctp_inq_init(&ep->base.inqueue);
  90
  91         /* Set its top-half handler */
  92         sctp_inq_set_th_handler(&ep->base.inqueue,
  93                                 (void (*)(void *))sctp_endpoint_bh_rcv, ep);
  94
  95         /* Initialize the bind addr area */
  96         sctp_bind_addr_init(&ep->base.bind_addr, 0);
  97         rwlock_init(&ep->base.addr_lock);
  98
  99         /* Remember who we are attached to.  */
 100         ep->base.sk = sk;
 101         sock_hold(ep->base.sk);
 102
 103         /* Create the lists of associations.  */
 104         INIT_LIST_HEAD(&ep->asocs);
 105
 106         /* Use SCTP specific send buffer space queues.  */
 107         ep->sndbuf_policy = sctp_sndbuf_policy;
 108         sk->sk_write_space = sctp_write_space;
 109         sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
 110
 111         /* Get the receive buffer policy for this endpoint */
 112         ep->rcvbuf_policy = sctp_rcvbuf_policy;
 113
 114         /* Initialize the secret key used with cookie. */
 115         get_random_bytes(&ep->secret_key[0], SCTP_SECRET_SIZE);
 116         ep->last_key = ep->current_key = 0;
 117         ep->key_changed_at = jiffies;
 118
 119         return ep;
 120 }
 121
 122 /* Create a sctp_endpoint with all that boring stuff initialized.
 123  * Returns NULL if there isn't enough memory.
 124  */
 125 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
 126 {
 127         struct sctp_endpoint *ep;
 128
 129         /* Build a local endpoint. */
 130         ep = t_new(struct sctp_endpoint, gfp);
 131         if (!ep)
 132                 goto fail;
 133         if (!sctp_endpoint_init(ep, sk, gfp))
 134                 goto fail_init;
 135         ep->base.malloced = 1;
 136         SCTP_DBG_OBJCNT_INC(ep);
 137         return ep;
 138
 139 fail_init:
 140         kfree(ep);
 141 fail:
 142         return NULL;
 143 }
 144
 145 /* Add an association to an endpoint.  */
 146 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
 147                             struct sctp_association *asoc)
 148 {
 149         struct sock *sk = ep->base.sk;
 150
 151         /* If this is a temporary association, don't bother
 152          * since we'll be removing it shortly and don't
 153          * want anyone to find it anyway.
 154          */
 155         if (asoc->temp)
 156                 return;
 157
 158         /* Now just add it to our list of asocs */
 159         list_add_tail(&asoc->asocs, &ep->asocs);
 160
 161         /* Increment the backlog value for a TCP-style listening socket. */
 162         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
 163                 sk->sk_ack_backlog++;
 164 }
 165
 166 /* Free the endpoint structure.  Delay cleanup until
 167  * all users have released their reference count on this structure.
 168  */
 169 void sctp_endpoint_free(struct sctp_endpoint *ep)
 170 {
 171         ep->base.dead = 1;
 172
 173         ep->base.sk->sk_state = SCTP_SS_CLOSED;
 174
 175         /* Unlink this endpoint, so we can't find it again! */
 176         sctp_unhash_endpoint(ep);
 177
 178         sctp_endpoint_put(ep);
 179 }
 180
 181 /* Final destructor for endpoint.  */
 182 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
 183 {
 184         SCTP_ASSERT(ep->base.dead, "Endpoint is not dead", return);
 185
 186         /* Free up the HMAC transform. */
 187         crypto_free_hash(sctp_sk(ep->base.sk)->hmac);
 188
 189         /* Free the digest buffer */
 190         kfree(ep->digest);
 191
 192         /* Cleanup. */
 193         sctp_inq_free(&ep->base.inqueue);
 194         sctp_bind_addr_free(&ep->base.bind_addr);
 195
 196         /* Remove and free the port */
 197         if (sctp_sk(ep->base.sk)->bind_hash)
 198                 sctp_put_port(ep->base.sk);
 199
 200         /* Give up our hold on the sock. */
 201         if (ep->base.sk)
 202                 sock_put(ep->base.sk);
 203
 204         /* Finally, free up our memory. */
 205         if (ep->base.malloced) {
 206                 kfree(ep);
 207                 SCTP_DBG_OBJCNT_DEC(ep);
 208         }
 209 }
 210
 211 /* Hold a reference to an endpoint. */
 212 void sctp_endpoint_hold(struct sctp_endpoint *ep)
 213 {
 214         atomic_inc(&ep->base.refcnt);
 215 }
 216
 217 /* Release a reference to an endpoint and clean up if there are
 218  * no more references.
 219  */
 220 void sctp_endpoint_put(struct sctp_endpoint *ep)
 221 {
 222         if (atomic_dec_and_test(&ep->base.refcnt))
 223                 sctp_endpoint_destroy(ep);
 224 }
 225
 226 /* Is this the endpoint we are looking for?  */
 227 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
 228                                                const union sctp_addr *laddr)
 229 {
 230         struct sctp_endpoint *retval;
 231
 232         sctp_read_lock(&ep->base.addr_lock);
 233         if (htons(ep->base.bind_addr.port) == laddr->v4.sin_port) {
 234                 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
 235                                          sctp_sk(ep->base.sk))) {
 236                         retval = ep;
 237                         goto out;
 238                 }
 239         }
 240
 241         retval = NULL;
 242
 243 out:
 244         sctp_read_unlock(&ep->base.addr_lock);
 245         return retval;
 246 }
 247
 248 /* Find the association that goes with this chunk.
 249  * We do a linear search of the associations for this endpoint.
 250  * We return the matching transport address too.
 251  */
 252 static struct sctp_association *__sctp_endpoint_lookup_assoc(
 253         const struct sctp_endpoint *ep,
 254         const union sctp_addr *paddr,
 255         struct sctp_transport **transport)
 256 {
 257         int rport;
 258         struct sctp_association *asoc;
 259         struct list_head *pos;
 260         union sctp_addr tmp;
 261         flip_to_n(&tmp, paddr);
 262
 263         rport = paddr->v4.sin_port;
 264
 265         list_for_each(pos, &ep->asocs) {
 266                 asoc = list_entry(pos, struct sctp_association, asocs);
 267                 if (rport == asoc->peer.port) {
 268                         sctp_read_lock(&asoc->base.addr_lock);
 269                         *transport = sctp_assoc_lookup_paddr(asoc, &tmp);
 270                         sctp_read_unlock(&asoc->base.addr_lock);
 271
 272                         if (*transport)
 273                                 return asoc;
 274                 }
 275         }
 276
 277         *transport = NULL;
 278         return NULL;
 279 }
 280
 281 /* Lookup association on an endpoint based on a peer address.  BH-safe.  */
 282 struct sctp_association *sctp_endpoint_lookup_assoc(
 283         const struct sctp_endpoint *ep,
 284         const union sctp_addr *paddr,
 285         struct sctp_transport **transport)
 286 {
 287         struct sctp_association *asoc;
 288
 289         sctp_local_bh_disable();
 290         asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport);
 291         sctp_local_bh_enable();
 292
 293         return asoc;
 294 }
 295
 296 /* Look for any peeled off association from the endpoint that matches the
 297  * given peer address.
 298  */
 299 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
 300                                 const union sctp_addr *paddr)
 301 {
 302         struct list_head *pos;
 303         struct sctp_sockaddr_entry *addr;
 304         struct sctp_bind_addr *bp;
 305
 306         sctp_read_lock(&ep->base.addr_lock);
 307         bp = &ep->base.bind_addr;
 308         list_for_each(pos, &bp->address_list) {
 309                 addr = list_entry(pos, struct sctp_sockaddr_entry, list);
 310                 if (sctp_has_association(&addr->a_h, paddr)) {
 311                         sctp_read_unlock(&ep->base.addr_lock);
 312                         return 1;
 313                 }
 314         }
 315         sctp_read_unlock(&ep->base.addr_lock);
 316
 317         return 0;
 318 }
 319
 320 /* Do delayed input processing.  This is scheduled by sctp_rcv().
 321  * This may be called on BH or task time.
 322  */
 323 static void sctp_endpoint_bh_rcv(struct sctp_endpoint *ep)
 324 {
 325         struct sctp_association *asoc;
 326         struct sock *sk;
 327         struct sctp_transport *transport;
 328         struct sctp_chunk *chunk;
 329         struct sctp_inq *inqueue;
 330         sctp_subtype_t subtype;
 331         sctp_state_t state;
 332         int error = 0;
 333
 334         if (ep->base.dead)
 335                 return;
 336
 337         asoc = NULL;
 338         inqueue = &ep->base.inqueue;
 339         sk = ep->base.sk;
 340
 341         while (NULL != (chunk = sctp_inq_pop(inqueue))) {
 342                 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
 343
 344                 /* We might have grown an association since last we
 345                  * looked, so try again.
 346                  *
 347                  * This happens when we've just processed our
 348                  * COOKIE-ECHO chunk.
 349                  */
 350                 if (NULL == chunk->asoc) {
 351                         asoc = sctp_endpoint_lookup_assoc(ep,
 352                                                           sctp_source(chunk),
 353                                                           &transport);
 354                         chunk->asoc = asoc;
 355                         chunk->transport = transport;
 356                 }
 357
 358                 state = asoc ? asoc->state : SCTP_STATE_CLOSED;
 359
 360                 /* Remember where the last DATA chunk came from so we
 361                  * know where to send the SACK.
 362                  */
 363                 if (asoc && sctp_chunk_is_data(chunk))
 364                         asoc->peer.last_data_from = chunk->transport;
 365                 else
 366                         SCTP_INC_STATS(SCTP_MIB_INCTRLCHUNKS);
 367
 368                 if (chunk->transport)
 369                         chunk->transport->last_time_heard = jiffies;
 370
 371                 error = sctp_do_sm(SCTP_EVENT_T_CHUNK, subtype, state,
 372                                    ep, asoc, chunk, GFP_ATOMIC);
 373
 374                 if (error && chunk)
 375                         chunk->pdiscard = 1;
 376
 377                 /* Check to see if the endpoint is freed in response to
 378                  * the incoming chunk. If so, get out of the while loop.
 379                  */
 380                 if (!sctp_sk(sk)->ep)
 381                         break;
 382         }
 383 }