1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /* SCTP kernel implementation
3 * Copyright (c) 1999-2000 Cisco, Inc.
4 * Copyright (c) 1999-2001 Motorola, Inc.
5 * Copyright (c) 2001-2002 International Business Machines, Corp.
6 * Copyright (c) 2001 Intel Corp.
7 * Copyright (c) 2001 Nokia, Inc.
8 * Copyright (c) 2001 La Monte H.P. Yarroll
10 * This file is part of the SCTP kernel implementation
12 * This abstraction represents an SCTP endpoint.
14 * Please send any bug reports or fixes you make to the
16 * lksctp developers <linux-sctp@vger.kernel.org>
18 * Written or modified by:
19 * La Monte H.P. Yarroll <piggy@acm.org>
20 * Karl Knutson <karl@athena.chicago.il.us>
21 * Jon Grimm <jgrimm@austin.ibm.com>
22 * Daisy Chang <daisyc@us.ibm.com>
23 * Dajiang Zhang <dajiang.zhang@nokia.com>
26 #include <linux/types.h>
27 #include <linux/slab.h>
29 #include <linux/random.h> /* get_random_bytes() */
32 #include <net/sctp/sctp.h>
33 #include <net/sctp/sm.h>
35 /* Forward declarations for internal helpers. */
36 static void sctp_endpoint_bh_rcv(struct work_struct *work);
39 * Initialize the base fields of the endpoint structure.
41 static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
45 struct net *net = sock_net(sk);
46 struct sctp_hmac_algo_param *auth_hmacs = NULL;
47 struct sctp_chunks_param *auth_chunks = NULL;
48 struct sctp_shared_key *null_key;
51 ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp);
55 ep->auth_enable = net->sctp.auth_enable;
56 if (ep->auth_enable) {
57 /* Allocate space for HMACS and CHUNKS authentication
58 * variables. There are arrays that we encode directly
59 * into parameters to make the rest of the operations easier.
61 auth_hmacs = kzalloc(struct_size(auth_hmacs, hmac_ids,
62 SCTP_AUTH_NUM_HMACS), gfp);
66 auth_chunks = kzalloc(sizeof(*auth_chunks) +
67 SCTP_NUM_CHUNK_TYPES, gfp);
71 /* Initialize the HMACS parameter.
72 * SCTP-AUTH: Section 3.3
73 * Every endpoint supporting SCTP chunk authentication MUST
74 * support the HMAC based on the SHA-1 algorithm.
76 auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO;
77 auth_hmacs->param_hdr.length =
78 htons(sizeof(struct sctp_paramhdr) + 2);
79 auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1);
81 /* Initialize the CHUNKS parameter */
82 auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS;
83 auth_chunks->param_hdr.length =
84 htons(sizeof(struct sctp_paramhdr));
86 /* If the Add-IP functionality is enabled, we must
87 * authenticate, ASCONF and ASCONF-ACK chunks
89 if (net->sctp.addip_enable) {
90 auth_chunks->chunks[0] = SCTP_CID_ASCONF;
91 auth_chunks->chunks[1] = SCTP_CID_ASCONF_ACK;
92 auth_chunks->param_hdr.length =
93 htons(sizeof(struct sctp_paramhdr) + 2);
96 /* Allocate and initialize transorms arrays for supported
99 err = sctp_auth_init_hmacs(ep, gfp);
104 /* Initialize the base structure. */
105 /* What type of endpoint are we? */
106 ep->base.type = SCTP_EP_TYPE_SOCKET;
108 /* Initialize the basic object fields. */
109 refcount_set(&ep->base.refcnt, 1);
110 ep->base.dead = false;
112 /* Create an input queue. */
113 sctp_inq_init(&ep->base.inqueue);
115 /* Set its top-half handler */
116 sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv);
118 /* Initialize the bind addr area */
119 sctp_bind_addr_init(&ep->base.bind_addr, 0);
121 /* Remember who we are attached to. */
123 sock_hold(ep->base.sk);
125 /* Create the lists of associations. */
126 INIT_LIST_HEAD(&ep->asocs);
128 /* Use SCTP specific send buffer space queues. */
129 ep->sndbuf_policy = net->sctp.sndbuf_policy;
131 sk->sk_data_ready = sctp_data_ready;
132 sk->sk_write_space = sctp_write_space;
133 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
135 /* Get the receive buffer policy for this endpoint */
136 ep->rcvbuf_policy = net->sctp.rcvbuf_policy;
138 /* Initialize the secret key used with cookie. */
139 get_random_bytes(ep->secret_key, sizeof(ep->secret_key));
141 /* SCTP-AUTH extensions*/
142 INIT_LIST_HEAD(&ep->endpoint_shared_keys);
143 null_key = sctp_auth_shkey_create(0, gfp);
147 list_add(&null_key->key_list, &ep->endpoint_shared_keys);
149 /* Add the null key to the endpoint shared keys list and
150 * set the hmcas and chunks pointers.
152 ep->auth_hmacs_list = auth_hmacs;
153 ep->auth_chunk_list = auth_chunks;
154 ep->prsctp_enable = net->sctp.prsctp_enable;
155 ep->reconf_enable = net->sctp.reconf_enable;
160 sctp_auth_destroy_hmacs(ep->auth_hmacs);
162 /* Free all allocations */
170 /* Create a sctp_endpoint with all that boring stuff initialized.
171 * Returns NULL if there isn't enough memory.
173 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
175 struct sctp_endpoint *ep;
177 /* Build a local endpoint. */
178 ep = kzalloc(sizeof(*ep), gfp);
182 if (!sctp_endpoint_init(ep, sk, gfp))
185 SCTP_DBG_OBJCNT_INC(ep);
194 /* Add an association to an endpoint. */
195 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
196 struct sctp_association *asoc)
198 struct sock *sk = ep->base.sk;
200 /* If this is a temporary association, don't bother
201 * since we'll be removing it shortly and don't
202 * want anyone to find it anyway.
207 /* Now just add it to our list of asocs */
208 list_add_tail(&asoc->asocs, &ep->asocs);
210 /* Increment the backlog value for a TCP-style listening socket. */
211 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
212 sk->sk_ack_backlog++;
215 /* Free the endpoint structure. Delay cleanup until
216 * all users have released their reference count on this structure.
218 void sctp_endpoint_free(struct sctp_endpoint *ep)
220 ep->base.dead = true;
222 inet_sk_set_state(ep->base.sk, SCTP_SS_CLOSED);
224 /* Unlink this endpoint, so we can't find it again! */
225 sctp_unhash_endpoint(ep);
227 sctp_endpoint_put(ep);
230 /* Final destructor for endpoint. */
231 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
235 if (unlikely(!ep->base.dead)) {
236 WARN(1, "Attempt to destroy undead endpoint %p!\n", ep);
240 /* Free the digest buffer */
243 /* SCTP-AUTH: Free up AUTH releated data such as shared keys
244 * chunks and hmacs arrays that were allocated
246 sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
247 kfree(ep->auth_hmacs_list);
248 kfree(ep->auth_chunk_list);
250 /* AUTH - Free any allocated HMAC transform containers */
251 sctp_auth_destroy_hmacs(ep->auth_hmacs);
254 sctp_inq_free(&ep->base.inqueue);
255 sctp_bind_addr_free(&ep->base.bind_addr);
257 memset(ep->secret_key, 0, sizeof(ep->secret_key));
260 /* Remove and free the port */
261 if (sctp_sk(sk)->bind_hash)
264 sctp_sk(sk)->ep = NULL;
265 /* Give up our hold on the sock */
269 SCTP_DBG_OBJCNT_DEC(ep);
272 /* Hold a reference to an endpoint. */
273 void sctp_endpoint_hold(struct sctp_endpoint *ep)
275 refcount_inc(&ep->base.refcnt);
278 /* Release a reference to an endpoint and clean up if there are
279 * no more references.
281 void sctp_endpoint_put(struct sctp_endpoint *ep)
283 if (refcount_dec_and_test(&ep->base.refcnt))
284 sctp_endpoint_destroy(ep);
287 /* Is this the endpoint we are looking for? */
288 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
290 const union sctp_addr *laddr)
292 struct sctp_endpoint *retval = NULL;
294 if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) &&
295 net_eq(sock_net(ep->base.sk), net)) {
296 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
297 sctp_sk(ep->base.sk)))
304 /* Find the association that goes with this chunk.
305 * We lookup the transport from hashtable at first, then get association
308 struct sctp_association *sctp_endpoint_lookup_assoc(
309 const struct sctp_endpoint *ep,
310 const union sctp_addr *paddr,
311 struct sctp_transport **transport)
313 struct sctp_association *asoc = NULL;
314 struct sctp_transport *t;
318 /* If the local port is not set, there can't be any associations
321 if (!ep->base.bind_addr.port)
325 t = sctp_epaddr_lookup_transport(ep, paddr);
336 /* Look for any peeled off association from the endpoint that matches the
337 * given peer address.
339 bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
340 const union sctp_addr *paddr)
342 struct sctp_sockaddr_entry *addr;
343 struct sctp_bind_addr *bp;
344 struct net *net = sock_net(ep->base.sk);
346 bp = &ep->base.bind_addr;
347 /* This function is called with the socket lock held,
348 * so the address_list can not change.
350 list_for_each_entry(addr, &bp->address_list, list) {
351 if (sctp_has_association(net, &addr->a, paddr))
358 /* Do delayed input processing. This is scheduled by sctp_rcv().
359 * This may be called on BH or task time.
361 static void sctp_endpoint_bh_rcv(struct work_struct *work)
363 struct sctp_endpoint *ep =
364 container_of(work, struct sctp_endpoint,
365 base.inqueue.immediate);
366 struct sctp_association *asoc;
369 struct sctp_transport *transport;
370 struct sctp_chunk *chunk;
371 struct sctp_inq *inqueue;
372 union sctp_subtype subtype;
373 enum sctp_state state;
375 int first_time = 1; /* is this the first time through the loop */
381 inqueue = &ep->base.inqueue;
385 while (NULL != (chunk = sctp_inq_pop(inqueue))) {
386 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
388 /* If the first chunk in the packet is AUTH, do special
389 * processing specified in Section 6.3 of SCTP-AUTH spec
391 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
392 struct sctp_chunkhdr *next_hdr;
394 next_hdr = sctp_inq_peek(inqueue);
398 /* If the next chunk is COOKIE-ECHO, skip the AUTH
399 * chunk while saving a pointer to it so we can do
400 * Authentication later (during cookie-echo
403 if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
404 chunk->auth_chunk = skb_clone(chunk->skb,
411 /* We might have grown an association since last we
412 * looked, so try again.
414 * This happens when we've just processed our
417 if (NULL == chunk->asoc) {
418 asoc = sctp_endpoint_lookup_assoc(ep,
422 chunk->transport = transport;
425 state = asoc ? asoc->state : SCTP_STATE_CLOSED;
426 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
429 /* Remember where the last DATA chunk came from so we
430 * know where to send the SACK.
432 if (asoc && sctp_chunk_is_data(chunk))
433 asoc->peer.last_data_from = chunk->transport;
435 SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
437 asoc->stats.ictrlchunks++;
440 if (chunk->transport)
441 chunk->transport->last_time_heard = ktime_get();
443 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
444 ep, asoc, chunk, GFP_ATOMIC);
449 /* Check to see if the endpoint is freed in response to
450 * the incoming chunk. If so, get out of the while loop.
452 if (!sctp_sk(sk)->ep)