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