// SPDX-License-Identifier: GPL-2.0-or-later /* SCTP kernel implementation * Copyright (c) 1999-2000 Cisco, Inc. * Copyright (c) 1999-2001 Motorola, Inc. * Copyright (c) 2001-2002 International Business Machines, Corp. * Copyright (c) 2001 Intel Corp. * Copyright (c) 2001 Nokia, Inc. * Copyright (c) 2001 La Monte H.P. Yarroll * * This file is part of the SCTP kernel implementation * * This abstraction represents an SCTP endpoint. * * Please send any bug reports or fixes you make to the * email address(es): * lksctp developers <linux-sctp@vger.kernel.org> * * Written or modified by: * La Monte H.P. Yarroll <piggy@acm.org> * Karl Knutson <karl@athena.chicago.il.us> * Jon Grimm <jgrimm@austin.ibm.com> * Daisy Chang <daisyc@us.ibm.com> * Dajiang Zhang <dajiang.zhang@nokia.com> */ #include <linux/types.h> #include <linux/slab.h> #include <linux/in.h> #include <linux/random.h> /* get_random_bytes() */ #include <net/sock.h> #include <net/ipv6.h> #include <net/sctp/sctp.h> #include <net/sctp/sm.h> /* Forward declarations for internal helpers. */ static void sctp_endpoint_bh_rcv(struct work_struct *work); /* * Initialize the base fields of the endpoint structure. */ static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep, struct sock *sk, gfp_t gfp) { struct net *net = sock_net(sk); struct sctp_shared_key *null_key; ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp); if (!ep->digest) return NULL; ep->asconf_enable = net->sctp.addip_enable; ep->auth_enable = net->sctp.auth_enable; if (ep->auth_enable) { if (sctp_auth_init(ep, gfp)) goto nomem; if (ep->asconf_enable) { sctp_auth_ep_add_chunkid(ep, SCTP_CID_ASCONF); sctp_auth_ep_add_chunkid(ep, SCTP_CID_ASCONF_ACK); } } /* Initialize the base structure. */ /* What type of endpoint are we? */ ep->base.type = SCTP_EP_TYPE_SOCKET; /* Initialize the basic object fields. */ refcount_set(&ep->base.refcnt, 1); ep->base.dead = false; /* Create an input queue. */ sctp_inq_init(&ep->base.inqueue); /* Set its top-half handler */ sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv); /* Initialize the bind addr area */ sctp_bind_addr_init(&ep->base.bind_addr, 0); /* Create the lists of associations. */ INIT_LIST_HEAD(&ep->asocs); /* Use SCTP specific send buffer space queues. */ ep->sndbuf_policy = net->sctp.sndbuf_policy; sk->sk_data_ready = sctp_data_ready; sk->sk_write_space = sctp_write_space; sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); /* Get the receive buffer policy for this endpoint */ ep->rcvbuf_policy = net->sctp.rcvbuf_policy; /* Initialize the secret key used with cookie. */ get_random_bytes(ep->secret_key, sizeof(ep->secret_key)); /* SCTP-AUTH extensions*/ INIT_LIST_HEAD(&ep->endpoint_shared_keys); null_key = sctp_auth_shkey_create(0, gfp); if (!null_key) goto nomem_shkey; list_add(&null_key->key_list, &ep->endpoint_shared_keys); /* Add the null key to the endpoint shared keys list and * set the hmcas and chunks pointers. */ ep->prsctp_enable = net->sctp.prsctp_enable; ep->reconf_enable = net->sctp.reconf_enable; ep->ecn_enable = net->sctp.ecn_enable; /* Remember who we are attached to. */ ep->base.sk = sk; ep->base.net = sock_net(sk); sock_hold(ep->base.sk); return ep; nomem_shkey: sctp_auth_free(ep); nomem: kfree(ep->digest); return NULL; } /* Create a sctp_endpoint with all that boring stuff initialized. * Returns NULL if there isn't enough memory. */ struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp) { struct sctp_endpoint *ep; /* Build a local endpoint. */ ep = kzalloc(sizeof(*ep), gfp); if (!ep) goto fail; if (!sctp_endpoint_init(ep, sk, gfp)) goto fail_init; SCTP_DBG_OBJCNT_INC(ep); return ep; fail_init: kfree(ep); fail: return NULL; } /* Add an association to an endpoint. */ void sctp_endpoint_add_asoc(struct sctp_endpoint *ep, struct sctp_association *asoc) { struct sock *sk = ep->base.sk; /* If this is a temporary association, don't bother * since we'll be removing it shortly and don't * want anyone to find it anyway. */ if (asoc->temp) return; /* Now just add it to our list of asocs */ list_add_tail(&asoc->asocs, &ep->asocs); /* Increment the backlog value for a TCP-style listening socket. */ if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING)) sk_acceptq_added(sk); } /* Free the endpoint structure. Delay cleanup until * all users have released their reference count on this structure. */ void sctp_endpoint_free(struct sctp_endpoint *ep) { ep->base.dead = true; inet_sk_set_state(ep->base.sk, SCTP_SS_CLOSED); /* Unlink this endpoint, so we can't find it again! */ sctp_unhash_endpoint(ep); sctp_endpoint_put(ep); } /* Final destructor for endpoint. */ static void sctp_endpoint_destroy_rcu(struct rcu_head *head) { struct sctp_endpoint *ep = container_of(head, struct sctp_endpoint, rcu); struct sock *sk = ep->base.sk; sctp_sk(sk)->ep = NULL; sock_put(sk); kfree(ep); SCTP_DBG_OBJCNT_DEC(ep); } static void sctp_endpoint_destroy(struct sctp_endpoint *ep) { struct sock *sk; if (unlikely(!ep->base.dead)) { WARN(1, "Attempt to destroy undead endpoint %p!\n", ep); return; } /* Free the digest buffer */ kfree(ep->digest); /* SCTP-AUTH: Free up AUTH releated data such as shared keys * chunks and hmacs arrays that were allocated */ sctp_auth_destroy_keys(&ep->endpoint_shared_keys); sctp_auth_free(ep); /* Cleanup. */ sctp_inq_free(&ep->base.inqueue); sctp_bind_addr_free(&ep->base.bind_addr); memset(ep->secret_key, 0, sizeof(ep->secret_key)); sk = ep->base.sk; /* Remove and free the port */ if (sctp_sk(sk)->bind_hash) sctp_put_port(sk); call_rcu(&ep->rcu, sctp_endpoint_destroy_rcu); } /* Hold a reference to an endpoint. */ int sctp_endpoint_hold(struct sctp_endpoint *ep) { return refcount_inc_not_zero(&ep->base.refcnt); } /* Release a reference to an endpoint and clean up if there are * no more references. */ void sctp_endpoint_put(struct sctp_endpoint *ep) { if (refcount_dec_and_test(&ep->base.refcnt)) sctp_endpoint_destroy(ep); } /* Is this the endpoint we are looking for? */ struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep, struct net *net, const union sctp_addr *laddr) { struct sctp_endpoint *retval = NULL; if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) && net_eq(ep->base.net, net)) { if (sctp_bind_addr_match(&ep->base.bind_addr, laddr, sctp_sk(ep->base.sk))) retval = ep; } return retval; } /* Find the association that goes with this chunk. * We lookup the transport from hashtable at first, then get association * through t->assoc. */ struct sctp_association *sctp_endpoint_lookup_assoc( const struct sctp_endpoint *ep, const union sctp_addr *paddr, struct sctp_transport **transport) { struct sctp_association *asoc = NULL; struct sctp_transport *t; *transport = NULL; /* If the local port is not set, there can't be any associations * on this endpoint. */ if (!ep->base.bind_addr.port) return NULL; rcu_read_lock(); t = sctp_epaddr_lookup_transport(ep, paddr); if (!t) goto out; *transport = t; asoc = t->asoc; out: rcu_read_unlock(); return asoc; } /* Look for any peeled off association from the endpoint that matches the * given peer address. */ bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep, const union sctp_addr *paddr) { struct sctp_sockaddr_entry *addr; struct net *net = ep->base.net; struct sctp_bind_addr *bp; bp = &ep->base.bind_addr; /* This function is called with the socket lock held, * so the address_list can not change. */ list_for_each_entry(addr, &bp->address_list, list) { if (sctp_has_association(net, &addr->a, paddr)) return true; } return false; } /* Do delayed input processing. This is scheduled by sctp_rcv(). * This may be called on BH or task time. */ static void sctp_endpoint_bh_rcv(struct work_struct *work) { struct sctp_endpoint *ep = container_of(work, struct sctp_endpoint, base.inqueue.immediate); struct sctp_association *asoc; struct sock *sk; struct net *net; struct sctp_transport *transport; struct sctp_chunk *chunk; struct sctp_inq *inqueue; union sctp_subtype subtype; enum sctp_state state; int error = 0; int first_time = 1; /* is this the first time through the loop */ if (ep->base.dead) return; asoc = NULL; inqueue = &ep->base.inqueue; sk = ep->base.sk; net = sock_net(sk); while (NULL != (chunk = sctp_inq_pop(inqueue))) { subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type); /* If the first chunk in the packet is AUTH, do special * processing specified in Section 6.3 of SCTP-AUTH spec */ if (first_time && (subtype.chunk == SCTP_CID_AUTH)) { struct sctp_chunkhdr *next_hdr; next_hdr = sctp_inq_peek(inqueue); if (!next_hdr) goto normal; /* If the next chunk is COOKIE-ECHO, skip the AUTH * chunk while saving a pointer to it so we can do * Authentication later (during cookie-echo * processing). */ if (next_hdr->type == SCTP_CID_COOKIE_ECHO) { chunk->auth_chunk = skb_clone(chunk->skb, GFP_ATOMIC); chunk->auth = 1; continue; } } normal: /* We might have grown an association since last we * looked, so try again. * * This happens when we've just processed our * COOKIE-ECHO chunk. */ if (NULL == chunk->asoc) { asoc = sctp_endpoint_lookup_assoc(ep, sctp_source(chunk), &transport); chunk->asoc = asoc; chunk->transport = transport; } state = asoc ? asoc->state : SCTP_STATE_CLOSED; if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth) continue; /* Remember where the last DATA chunk came from so we * know where to send the SACK. */ if (asoc && sctp_chunk_is_data(chunk)) asoc->peer.last_data_from = chunk->transport; else { SCTP_INC_STATS(ep->base.net, SCTP_MIB_INCTRLCHUNKS); if (asoc) asoc->stats.ictrlchunks++; } if (chunk->transport) chunk->transport->last_time_heard = ktime_get(); error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state, ep, asoc, chunk, GFP_ATOMIC); if (error && chunk) chunk->pdiscard = 1; /* Check to see if the endpoint is freed in response to * the incoming chunk. If so, get out of the while loop. */ if (!sctp_sk(sk)->ep) break; if (first_time) first_time = 0; } }