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-rw-r--r--net/sctp/input.c913
1 files changed, 913 insertions, 0 deletions
diff --git a/net/sctp/input.c b/net/sctp/input.c
new file mode 100644
index 00000000000..b719a77d66b
--- /dev/null
+++ b/net/sctp/input.c
@@ -0,0 +1,913 @@
+/* SCTP kernel reference Implementation
+ * Copyright (c) 1999-2000 Cisco, Inc.
+ * Copyright (c) 1999-2001 Motorola, Inc.
+ * Copyright (c) 2001-2003 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 reference Implementation
+ *
+ * These functions handle all input from the IP layer into SCTP.
+ *
+ * The SCTP reference implementation is free software;
+ * you can redistribute it and/or modify it under the terms of
+ * the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * The SCTP reference implementation is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied
+ * ************************
+ * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GNU CC; see the file COPYING. If not, write to
+ * the Free Software Foundation, 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ * Please send any bug reports or fixes you make to the
+ * email address(es):
+ * lksctp developers <lksctp-developers@lists.sourceforge.net>
+ *
+ * Or submit a bug report through the following website:
+ * http://www.sf.net/projects/lksctp
+ *
+ * Written or modified by:
+ * La Monte H.P. Yarroll <piggy@acm.org>
+ * Karl Knutson <karl@athena.chicago.il.us>
+ * Xingang Guo <xingang.guo@intel.com>
+ * Jon Grimm <jgrimm@us.ibm.com>
+ * Hui Huang <hui.huang@nokia.com>
+ * Daisy Chang <daisyc@us.ibm.com>
+ * Sridhar Samudrala <sri@us.ibm.com>
+ * Ardelle Fan <ardelle.fan@intel.com>
+ *
+ * Any bugs reported given to us we will try to fix... any fixes shared will
+ * be incorporated into the next SCTP release.
+ */
+
+#include <linux/types.h>
+#include <linux/list.h> /* For struct list_head */
+#include <linux/socket.h>
+#include <linux/ip.h>
+#include <linux/time.h> /* For struct timeval */
+#include <net/ip.h>
+#include <net/icmp.h>
+#include <net/snmp.h>
+#include <net/sock.h>
+#include <net/xfrm.h>
+#include <net/sctp/sctp.h>
+#include <net/sctp/sm.h>
+
+/* Forward declarations for internal helpers. */
+static int sctp_rcv_ootb(struct sk_buff *);
+static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb,
+ const union sctp_addr *laddr,
+ const union sctp_addr *paddr,
+ struct sctp_transport **transportp);
+static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr);
+static struct sctp_association *__sctp_lookup_association(
+ const union sctp_addr *local,
+ const union sctp_addr *peer,
+ struct sctp_transport **pt);
+
+
+/* Calculate the SCTP checksum of an SCTP packet. */
+static inline int sctp_rcv_checksum(struct sk_buff *skb)
+{
+ struct sctphdr *sh;
+ __u32 cmp, val;
+ struct sk_buff *list = skb_shinfo(skb)->frag_list;
+
+ sh = (struct sctphdr *) skb->h.raw;
+ cmp = ntohl(sh->checksum);
+
+ val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb));
+
+ for (; list; list = list->next)
+ val = sctp_update_cksum((__u8 *)list->data, skb_headlen(list),
+ val);
+
+ val = sctp_end_cksum(val);
+
+ if (val != cmp) {
+ /* CRC failure, dump it. */
+ SCTP_INC_STATS_BH(SCTP_MIB_CHECKSUMERRORS);
+ return -1;
+ }
+ return 0;
+}
+
+/* The free routine for skbuffs that sctp receives */
+static void sctp_rfree(struct sk_buff *skb)
+{
+ atomic_sub(sizeof(struct sctp_chunk),&skb->sk->sk_rmem_alloc);
+ sock_rfree(skb);
+}
+
+/* The ownership wrapper routine to do receive buffer accounting */
+static void sctp_rcv_set_owner_r(struct sk_buff *skb, struct sock *sk)
+{
+ skb_set_owner_r(skb,sk);
+ skb->destructor = sctp_rfree;
+ atomic_add(sizeof(struct sctp_chunk),&sk->sk_rmem_alloc);
+}
+
+/*
+ * This is the routine which IP calls when receiving an SCTP packet.
+ */
+int sctp_rcv(struct sk_buff *skb)
+{
+ struct sock *sk;
+ struct sctp_association *asoc;
+ struct sctp_endpoint *ep = NULL;
+ struct sctp_ep_common *rcvr;
+ struct sctp_transport *transport = NULL;
+ struct sctp_chunk *chunk;
+ struct sctphdr *sh;
+ union sctp_addr src;
+ union sctp_addr dest;
+ int family;
+ struct sctp_af *af;
+ int ret = 0;
+
+ if (skb->pkt_type!=PACKET_HOST)
+ goto discard_it;
+
+ SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS);
+
+ sh = (struct sctphdr *) skb->h.raw;
+
+ /* Pull up the IP and SCTP headers. */
+ __skb_pull(skb, skb->h.raw - skb->data);
+ if (skb->len < sizeof(struct sctphdr))
+ goto discard_it;
+ if (sctp_rcv_checksum(skb) < 0)
+ goto discard_it;
+
+ skb_pull(skb, sizeof(struct sctphdr));
+
+ /* Make sure we at least have chunk headers worth of data left. */
+ if (skb->len < sizeof(struct sctp_chunkhdr))
+ goto discard_it;
+
+ family = ipver2af(skb->nh.iph->version);
+ af = sctp_get_af_specific(family);
+ if (unlikely(!af))
+ goto discard_it;
+
+ /* Initialize local addresses for lookups. */
+ af->from_skb(&src, skb, 1);
+ af->from_skb(&dest, skb, 0);
+
+ /* If the packet is to or from a non-unicast address,
+ * silently discard the packet.
+ *
+ * This is not clearly defined in the RFC except in section
+ * 8.4 - OOTB handling. However, based on the book "Stream Control
+ * Transmission Protocol" 2.1, "It is important to note that the
+ * IP address of an SCTP transport address must be a routable
+ * unicast address. In other words, IP multicast addresses and
+ * IP broadcast addresses cannot be used in an SCTP transport
+ * address."
+ */
+ if (!af->addr_valid(&src, NULL) || !af->addr_valid(&dest, NULL))
+ goto discard_it;
+
+ asoc = __sctp_rcv_lookup(skb, &src, &dest, &transport);
+
+ /*
+ * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
+ * An SCTP packet is called an "out of the blue" (OOTB)
+ * packet if it is correctly formed, i.e., passed the
+ * receiver's checksum check, but the receiver is not
+ * able to identify the association to which this
+ * packet belongs.
+ */
+ if (!asoc) {
+ ep = __sctp_rcv_lookup_endpoint(&dest);
+ if (sctp_rcv_ootb(skb)) {
+ SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES);
+ goto discard_release;
+ }
+ }
+
+ /* Retrieve the common input handling substructure. */
+ rcvr = asoc ? &asoc->base : &ep->base;
+ sk = rcvr->sk;
+
+ if ((sk) && (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf)) {
+ goto discard_release;
+ }
+
+
+ /* SCTP seems to always need a timestamp right now (FIXME) */
+ if (skb->stamp.tv_sec == 0) {
+ do_gettimeofday(&skb->stamp);
+ sock_enable_timestamp(sk);
+ }
+
+ if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
+ goto discard_release;
+
+ ret = sk_filter(sk, skb, 1);
+ if (ret)
+ goto discard_release;
+
+ /* Create an SCTP packet structure. */
+ chunk = sctp_chunkify(skb, asoc, sk);
+ if (!chunk) {
+ ret = -ENOMEM;
+ goto discard_release;
+ }
+
+ sctp_rcv_set_owner_r(skb,sk);
+
+ /* Remember what endpoint is to handle this packet. */
+ chunk->rcvr = rcvr;
+
+ /* Remember the SCTP header. */
+ chunk->sctp_hdr = sh;
+
+ /* Set the source and destination addresses of the incoming chunk. */
+ sctp_init_addrs(chunk, &src, &dest);
+
+ /* Remember where we came from. */
+ chunk->transport = transport;
+
+ /* Acquire access to the sock lock. Note: We are safe from other
+ * bottom halves on this lock, but a user may be in the lock too,
+ * so check if it is busy.
+ */
+ sctp_bh_lock_sock(sk);
+
+ if (sock_owned_by_user(sk))
+ sk_add_backlog(sk, (struct sk_buff *) chunk);
+ else
+ sctp_backlog_rcv(sk, (struct sk_buff *) chunk);
+
+ /* Release the sock and any reference counts we took in the
+ * lookup calls.
+ */
+ sctp_bh_unlock_sock(sk);
+ if (asoc)
+ sctp_association_put(asoc);
+ else
+ sctp_endpoint_put(ep);
+ sock_put(sk);
+ return ret;
+
+discard_it:
+ kfree_skb(skb);
+ return ret;
+
+discard_release:
+ /* Release any structures we may be holding. */
+ if (asoc) {
+ sock_put(asoc->base.sk);
+ sctp_association_put(asoc);
+ } else {
+ sock_put(ep->base.sk);
+ sctp_endpoint_put(ep);
+ }
+
+ goto discard_it;
+}
+
+/* Handle second half of inbound skb processing. If the sock was busy,
+ * we may have need to delay processing until later when the sock is
+ * released (on the backlog). If not busy, we call this routine
+ * directly from the bottom half.
+ */
+int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
+{
+ struct sctp_chunk *chunk;
+ struct sctp_inq *inqueue;
+
+ /* One day chunk will live inside the skb, but for
+ * now this works.
+ */
+ chunk = (struct sctp_chunk *) skb;
+ inqueue = &chunk->rcvr->inqueue;
+
+ sctp_inq_push(inqueue, chunk);
+ return 0;
+}
+
+/* Handle icmp frag needed error. */
+void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
+ struct sctp_transport *t, __u32 pmtu)
+{
+ if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) {
+ printk(KERN_WARNING "%s: Reported pmtu %d too low, "
+ "using default minimum of %d\n", __FUNCTION__, pmtu,
+ SCTP_DEFAULT_MINSEGMENT);
+ pmtu = SCTP_DEFAULT_MINSEGMENT;
+ }
+
+ if (!sock_owned_by_user(sk) && t && (t->pmtu != pmtu)) {
+ t->pmtu = pmtu;
+ sctp_assoc_sync_pmtu(asoc);
+ sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD);
+ }
+}
+
+/*
+ * SCTP Implementer's Guide, 2.37 ICMP handling procedures
+ *
+ * ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
+ * or a "Protocol Unreachable" treat this message as an abort
+ * with the T bit set.
+ *
+ * This function sends an event to the state machine, which will abort the
+ * association.
+ *
+ */
+void sctp_icmp_proto_unreachable(struct sock *sk,
+ struct sctp_endpoint *ep,
+ struct sctp_association *asoc,
+ struct sctp_transport *t)
+{
+ SCTP_DEBUG_PRINTK("%s\n", __FUNCTION__);
+
+ sctp_do_sm(SCTP_EVENT_T_OTHER,
+ SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
+ asoc->state, asoc->ep, asoc, NULL,
+ GFP_ATOMIC);
+
+}
+
+/* Common lookup code for icmp/icmpv6 error handler. */
+struct sock *sctp_err_lookup(int family, struct sk_buff *skb,
+ struct sctphdr *sctphdr,
+ struct sctp_endpoint **epp,
+ struct sctp_association **app,
+ struct sctp_transport **tpp)
+{
+ union sctp_addr saddr;
+ union sctp_addr daddr;
+ struct sctp_af *af;
+ struct sock *sk = NULL;
+ struct sctp_endpoint *ep = NULL;
+ struct sctp_association *asoc = NULL;
+ struct sctp_transport *transport = NULL;
+
+ *app = NULL; *epp = NULL; *tpp = NULL;
+
+ af = sctp_get_af_specific(family);
+ if (unlikely(!af)) {
+ return NULL;
+ }
+
+ /* Initialize local addresses for lookups. */
+ af->from_skb(&saddr, skb, 1);
+ af->from_skb(&daddr, skb, 0);
+
+ /* Look for an association that matches the incoming ICMP error
+ * packet.
+ */
+ asoc = __sctp_lookup_association(&saddr, &daddr, &transport);
+ if (!asoc) {
+ /* If there is no matching association, see if it matches any
+ * endpoint. This may happen for an ICMP error generated in
+ * response to an INIT_ACK.
+ */
+ ep = __sctp_rcv_lookup_endpoint(&daddr);
+ if (!ep) {
+ return NULL;
+ }
+ }
+
+ if (asoc) {
+ sk = asoc->base.sk;
+
+ if (ntohl(sctphdr->vtag) != asoc->c.peer_vtag) {
+ ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
+ goto out;
+ }
+ } else
+ sk = ep->base.sk;
+
+ sctp_bh_lock_sock(sk);
+
+ /* If too many ICMPs get dropped on busy
+ * servers this needs to be solved differently.
+ */
+ if (sock_owned_by_user(sk))
+ NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS);
+
+ *epp = ep;
+ *app = asoc;
+ *tpp = transport;
+ return sk;
+
+out:
+ sock_put(sk);
+ if (asoc)
+ sctp_association_put(asoc);
+ if (ep)
+ sctp_endpoint_put(ep);
+ return NULL;
+}
+
+/* Common cleanup code for icmp/icmpv6 error handler. */
+void sctp_err_finish(struct sock *sk, struct sctp_endpoint *ep,
+ struct sctp_association *asoc)
+{
+ sctp_bh_unlock_sock(sk);
+ sock_put(sk);
+ if (asoc)
+ sctp_association_put(asoc);
+ if (ep)
+ sctp_endpoint_put(ep);
+}
+
+/*
+ * This routine is called by the ICMP module when it gets some
+ * sort of error condition. If err < 0 then the socket should
+ * be closed and the error returned to the user. If err > 0
+ * it's just the icmp type << 8 | icmp code. After adjustment
+ * header points to the first 8 bytes of the sctp header. We need
+ * to find the appropriate port.
+ *
+ * The locking strategy used here is very "optimistic". When
+ * someone else accesses the socket the ICMP is just dropped
+ * and for some paths there is no check at all.
+ * A more general error queue to queue errors for later handling
+ * is probably better.
+ *
+ */
+void sctp_v4_err(struct sk_buff *skb, __u32 info)
+{
+ struct iphdr *iph = (struct iphdr *)skb->data;
+ struct sctphdr *sh = (struct sctphdr *)(skb->data + (iph->ihl <<2));
+ int type = skb->h.icmph->type;
+ int code = skb->h.icmph->code;
+ struct sock *sk;
+ struct sctp_endpoint *ep;
+ struct sctp_association *asoc;
+ struct sctp_transport *transport;
+ struct inet_sock *inet;
+ char *saveip, *savesctp;
+ int err;
+
+ if (skb->len < ((iph->ihl << 2) + 8)) {
+ ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
+ return;
+ }
+
+ /* Fix up skb to look at the embedded net header. */
+ saveip = skb->nh.raw;
+ savesctp = skb->h.raw;
+ skb->nh.iph = iph;
+ skb->h.raw = (char *)sh;
+ sk = sctp_err_lookup(AF_INET, skb, sh, &ep, &asoc, &transport);
+ /* Put back, the original pointers. */
+ skb->nh.raw = saveip;
+ skb->h.raw = savesctp;
+ if (!sk) {
+ ICMP_INC_STATS_BH(ICMP_MIB_INERRORS);
+ return;
+ }
+ /* Warning: The sock lock is held. Remember to call
+ * sctp_err_finish!
+ */
+
+ switch (type) {
+ case ICMP_PARAMETERPROB:
+ err = EPROTO;
+ break;
+ case ICMP_DEST_UNREACH:
+ if (code > NR_ICMP_UNREACH)
+ goto out_unlock;
+
+ /* PMTU discovery (RFC1191) */
+ if (ICMP_FRAG_NEEDED == code) {
+ sctp_icmp_frag_needed(sk, asoc, transport, info);
+ goto out_unlock;
+ }
+ else {
+ if (ICMP_PROT_UNREACH == code) {
+ sctp_icmp_proto_unreachable(sk, ep, asoc,
+ transport);
+ goto out_unlock;
+ }
+ }
+ err = icmp_err_convert[code].errno;
+ break;
+ case ICMP_TIME_EXCEEDED:
+ /* Ignore any time exceeded errors due to fragment reassembly
+ * timeouts.
+ */
+ if (ICMP_EXC_FRAGTIME == code)
+ goto out_unlock;
+
+ err = EHOSTUNREACH;
+ break;
+ default:
+ goto out_unlock;
+ }
+
+ inet = inet_sk(sk);
+ if (!sock_owned_by_user(sk) && inet->recverr) {
+ sk->sk_err = err;
+ sk->sk_error_report(sk);
+ } else { /* Only an error on timeout */
+ sk->sk_err_soft = err;
+ }
+
+out_unlock:
+ sctp_err_finish(sk, ep, asoc);
+}
+
+/*
+ * RFC 2960, 8.4 - Handle "Out of the blue" Packets.
+ *
+ * This function scans all the chunks in the OOTB packet to determine if
+ * the packet should be discarded right away. If a response might be needed
+ * for this packet, or, if further processing is possible, the packet will
+ * be queued to a proper inqueue for the next phase of handling.
+ *
+ * Output:
+ * Return 0 - If further processing is needed.
+ * Return 1 - If the packet can be discarded right away.
+ */
+int sctp_rcv_ootb(struct sk_buff *skb)
+{
+ sctp_chunkhdr_t *ch;
+ __u8 *ch_end;
+ sctp_errhdr_t *err;
+
+ ch = (sctp_chunkhdr_t *) skb->data;
+ ch_end = ((__u8 *) ch) + WORD_ROUND(ntohs(ch->length));
+
+ /* Scan through all the chunks in the packet. */
+ while (ch_end > (__u8 *)ch && ch_end < skb->tail) {
+
+ /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the
+ * receiver MUST silently discard the OOTB packet and take no
+ * further action.
+ */
+ if (SCTP_CID_ABORT == ch->type)
+ goto discard;
+
+ /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE
+ * chunk, the receiver should silently discard the packet
+ * and take no further action.
+ */
+ if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type)
+ goto discard;
+
+ /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR
+ * or a COOKIE ACK the SCTP Packet should be silently
+ * discarded.
+ */
+ if (SCTP_CID_COOKIE_ACK == ch->type)
+ goto discard;
+
+ if (SCTP_CID_ERROR == ch->type) {
+ sctp_walk_errors(err, ch) {
+ if (SCTP_ERROR_STALE_COOKIE == err->cause)
+ goto discard;
+ }
+ }
+
+ ch = (sctp_chunkhdr_t *) ch_end;
+ ch_end = ((__u8 *) ch) + WORD_ROUND(ntohs(ch->length));
+ }
+
+ return 0;
+
+discard:
+ return 1;
+}
+
+/* Insert endpoint into the hash table. */
+static void __sctp_hash_endpoint(struct sctp_endpoint *ep)
+{
+ struct sctp_ep_common **epp;
+ struct sctp_ep_common *epb;
+ struct sctp_hashbucket *head;
+
+ epb = &ep->base;
+
+ epb->hashent = sctp_ep_hashfn(epb->bind_addr.port);
+ head = &sctp_ep_hashtable[epb->hashent];
+
+ sctp_write_lock(&head->lock);
+ epp = &head->chain;
+ epb->next = *epp;
+ if (epb->next)
+ (*epp)->pprev = &epb->next;
+ *epp = epb;
+ epb->pprev = epp;
+ sctp_write_unlock(&head->lock);
+}
+
+/* Add an endpoint to the hash. Local BH-safe. */
+void sctp_hash_endpoint(struct sctp_endpoint *ep)
+{
+ sctp_local_bh_disable();
+ __sctp_hash_endpoint(ep);
+ sctp_local_bh_enable();
+}
+
+/* Remove endpoint from the hash table. */
+static void __sctp_unhash_endpoint(struct sctp_endpoint *ep)
+{
+ struct sctp_hashbucket *head;
+ struct sctp_ep_common *epb;
+
+ epb = &ep->base;
+
+ epb->hashent = sctp_ep_hashfn(epb->bind_addr.port);
+
+ head = &sctp_ep_hashtable[epb->hashent];
+
+ sctp_write_lock(&head->lock);
+
+ if (epb->pprev) {
+ if (epb->next)
+ epb->next->pprev = epb->pprev;
+ *epb->pprev = epb->next;
+ epb->pprev = NULL;
+ }
+
+ sctp_write_unlock(&head->lock);
+}
+
+/* Remove endpoint from the hash. Local BH-safe. */
+void sctp_unhash_endpoint(struct sctp_endpoint *ep)
+{
+ sctp_local_bh_disable();
+ __sctp_unhash_endpoint(ep);
+ sctp_local_bh_enable();
+}
+
+/* Look up an endpoint. */
+static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr)
+{
+ struct sctp_hashbucket *head;
+ struct sctp_ep_common *epb;
+ struct sctp_endpoint *ep;
+ int hash;
+
+ hash = sctp_ep_hashfn(laddr->v4.sin_port);
+ head = &sctp_ep_hashtable[hash];
+ read_lock(&head->lock);
+ for (epb = head->chain; epb; epb = epb->next) {
+ ep = sctp_ep(epb);
+ if (sctp_endpoint_is_match(ep, laddr))
+ goto hit;
+ }
+
+ ep = sctp_sk((sctp_get_ctl_sock()))->ep;
+ epb = &ep->base;
+
+hit:
+ sctp_endpoint_hold(ep);
+ sock_hold(epb->sk);
+ read_unlock(&head->lock);
+ return ep;
+}
+
+/* Insert association into the hash table. */
+static void __sctp_hash_established(struct sctp_association *asoc)
+{
+ struct sctp_ep_common **epp;
+ struct sctp_ep_common *epb;
+ struct sctp_hashbucket *head;
+
+ epb = &asoc->base;
+
+ /* Calculate which chain this entry will belong to. */
+ epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, asoc->peer.port);
+
+ head = &sctp_assoc_hashtable[epb->hashent];
+
+ sctp_write_lock(&head->lock);
+ epp = &head->chain;
+ epb->next = *epp;
+ if (epb->next)
+ (*epp)->pprev = &epb->next;
+ *epp = epb;
+ epb->pprev = epp;
+ sctp_write_unlock(&head->lock);
+}
+
+/* Add an association to the hash. Local BH-safe. */
+void sctp_hash_established(struct sctp_association *asoc)
+{
+ sctp_local_bh_disable();
+ __sctp_hash_established(asoc);
+ sctp_local_bh_enable();
+}
+
+/* Remove association from the hash table. */
+static void __sctp_unhash_established(struct sctp_association *asoc)
+{
+ struct sctp_hashbucket *head;
+ struct sctp_ep_common *epb;
+
+ epb = &asoc->base;
+
+ epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port,
+ asoc->peer.port);
+
+ head = &sctp_assoc_hashtable[epb->hashent];
+
+ sctp_write_lock(&head->lock);
+
+ if (epb->pprev) {
+ if (epb->next)
+ epb->next->pprev = epb->pprev;
+ *epb->pprev = epb->next;
+ epb->pprev = NULL;
+ }
+
+ sctp_write_unlock(&head->lock);
+}
+
+/* Remove association from the hash table. Local BH-safe. */
+void sctp_unhash_established(struct sctp_association *asoc)
+{
+ sctp_local_bh_disable();
+ __sctp_unhash_established(asoc);
+ sctp_local_bh_enable();
+}
+
+/* Look up an association. */
+static struct sctp_association *__sctp_lookup_association(
+ const union sctp_addr *local,
+ const union sctp_addr *peer,
+ struct sctp_transport **pt)
+{
+ struct sctp_hashbucket *head;
+ struct sctp_ep_common *epb;
+ struct sctp_association *asoc;
+ struct sctp_transport *transport;
+ int hash;
+
+ /* Optimize here for direct hit, only listening connections can
+ * have wildcards anyways.
+ */
+ hash = sctp_assoc_hashfn(local->v4.sin_port, peer->v4.sin_port);
+ head = &sctp_assoc_hashtable[hash];
+ read_lock(&head->lock);
+ for (epb = head->chain; epb; epb = epb->next) {
+ asoc = sctp_assoc(epb);
+ transport = sctp_assoc_is_match(asoc, local, peer);
+ if (transport)
+ goto hit;
+ }
+
+ read_unlock(&head->lock);
+
+ return NULL;
+
+hit:
+ *pt = transport;
+ sctp_association_hold(asoc);
+ sock_hold(epb->sk);
+ read_unlock(&head->lock);
+ return asoc;
+}
+
+/* Look up an association. BH-safe. */
+SCTP_STATIC
+struct sctp_association *sctp_lookup_association(const union sctp_addr *laddr,
+ const union sctp_addr *paddr,
+ struct sctp_transport **transportp)
+{
+ struct sctp_association *asoc;
+
+ sctp_local_bh_disable();
+ asoc = __sctp_lookup_association(laddr, paddr, transportp);
+ sctp_local_bh_enable();
+
+ return asoc;
+}
+
+/* Is there an association matching the given local and peer addresses? */
+int sctp_has_association(const union sctp_addr *laddr,
+ const union sctp_addr *paddr)
+{
+ struct sctp_association *asoc;
+ struct sctp_transport *transport;
+
+ if ((asoc = sctp_lookup_association(laddr, paddr, &transport))) {
+ sock_put(asoc->base.sk);
+ sctp_association_put(asoc);
+ return 1;
+ }
+
+ return 0;
+}
+
+/*
+ * SCTP Implementors Guide, 2.18 Handling of address
+ * parameters within the INIT or INIT-ACK.
+ *
+ * D) When searching for a matching TCB upon reception of an INIT
+ * or INIT-ACK chunk the receiver SHOULD use not only the
+ * source address of the packet (containing the INIT or
+ * INIT-ACK) but the receiver SHOULD also use all valid
+ * address parameters contained within the chunk.
+ *
+ * 2.18.3 Solution description
+ *
+ * This new text clearly specifies to an implementor the need
+ * to look within the INIT or INIT-ACK. Any implementation that
+ * does not do this, may not be able to establish associations
+ * in certain circumstances.
+ *
+ */
+static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb,
+ const union sctp_addr *laddr, struct sctp_transport **transportp)
+{
+ struct sctp_association *asoc;
+ union sctp_addr addr;
+ union sctp_addr *paddr = &addr;
+ struct sctphdr *sh = (struct sctphdr *) skb->h.raw;
+ sctp_chunkhdr_t *ch;
+ union sctp_params params;
+ sctp_init_chunk_t *init;
+ struct sctp_transport *transport;
+ struct sctp_af *af;
+
+ ch = (sctp_chunkhdr_t *) skb->data;
+
+ /* If this is INIT/INIT-ACK look inside the chunk too. */
+ switch (ch->type) {
+ case SCTP_CID_INIT:
+ case SCTP_CID_INIT_ACK:
+ break;
+ default:
+ return NULL;
+ }
+
+ /* The code below will attempt to walk the chunk and extract
+ * parameter information. Before we do that, we need to verify
+ * that the chunk length doesn't cause overflow. Otherwise, we'll
+ * walk off the end.
+ */
+ if (WORD_ROUND(ntohs(ch->length)) > skb->len)
+ return NULL;
+
+ /*
+ * This code will NOT touch anything inside the chunk--it is
+ * strictly READ-ONLY.
+ *
+ * RFC 2960 3 SCTP packet Format
+ *
+ * Multiple chunks can be bundled into one SCTP packet up to
+ * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN
+ * COMPLETE chunks. These chunks MUST NOT be bundled with any
+ * other chunk in a packet. See Section 6.10 for more details
+ * on chunk bundling.
+ */
+
+ /* Find the start of the TLVs and the end of the chunk. This is
+ * the region we search for address parameters.
+ */
+ init = (sctp_init_chunk_t *)skb->data;
+
+ /* Walk the parameters looking for embedded addresses. */
+ sctp_walk_params(params, init, init_hdr.params) {
+
+ /* Note: Ignoring hostname addresses. */
+ af = sctp_get_af_specific(param_type2af(params.p->type));
+ if (!af)
+ continue;
+
+ af->from_addr_param(paddr, params.addr, ntohs(sh->source), 0);
+
+ asoc = __sctp_lookup_association(laddr, paddr, &transport);
+ if (asoc)
+ return asoc;
+ }
+
+ return NULL;
+}
+
+/* Lookup an association for an inbound skb. */
+static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb,
+ const union sctp_addr *paddr,
+ const union sctp_addr *laddr,
+ struct sctp_transport **transportp)
+{
+ struct sctp_association *asoc;
+
+ asoc = __sctp_lookup_association(laddr, paddr, transportp);
+
+ /* Further lookup for INIT/INIT-ACK packets.
+ * SCTP Implementors Guide, 2.18 Handling of address
+ * parameters within the INIT or INIT-ACK.
+ */
+ if (!asoc)
+ asoc = __sctp_rcv_init_lookup(skb, laddr, transportp);
+
+ return asoc;
+}
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-11-29 16:24:20 +0000