![Xin Long](/assets/img/avatar_default.png)
__sctp_lookup_association() is only invoked by sctp_v4_err() and sctp_rcv(), both which run on the rx BH, and it has been protected by rcu_read_lock [see ip_local_deliver_finish() / ipv6_rcv()]. So we can move it to sctp_lookup_association, only let sctp_lookup_association use rcu_read_lock. Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1212 lines
32 KiB
C
1212 lines
32 KiB
C
/* SCTP kernel implementation
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* Copyright (c) 1999-2000 Cisco, Inc.
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* Copyright (c) 1999-2001 Motorola, Inc.
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* Copyright (c) 2001-2003 International Business Machines, Corp.
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* Copyright (c) 2001 Intel Corp.
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* Copyright (c) 2001 Nokia, Inc.
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* Copyright (c) 2001 La Monte H.P. Yarroll
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*
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* This file is part of the SCTP kernel implementation
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*
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* These functions handle all input from the IP layer into SCTP.
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*
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* This SCTP implementation is free software;
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* you can redistribute it and/or modify it under the terms of
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* the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This SCTP implementation is distributed in the hope that it
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* will be useful, but WITHOUT ANY WARRANTY; without even the implied
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* ************************
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* warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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* See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GNU CC; see the file COPYING. If not, see
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* <http://www.gnu.org/licenses/>.
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*
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* Please send any bug reports or fixes you make to the
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* email address(es):
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* lksctp developers <linux-sctp@vger.kernel.org>
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*
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* Written or modified by:
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* La Monte H.P. Yarroll <piggy@acm.org>
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* Karl Knutson <karl@athena.chicago.il.us>
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* Xingang Guo <xingang.guo@intel.com>
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* Jon Grimm <jgrimm@us.ibm.com>
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* Hui Huang <hui.huang@nokia.com>
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* Daisy Chang <daisyc@us.ibm.com>
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* Sridhar Samudrala <sri@us.ibm.com>
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* Ardelle Fan <ardelle.fan@intel.com>
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*/
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#include <linux/types.h>
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#include <linux/list.h> /* For struct list_head */
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#include <linux/socket.h>
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#include <linux/ip.h>
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#include <linux/time.h> /* For struct timeval */
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#include <linux/slab.h>
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#include <net/ip.h>
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#include <net/icmp.h>
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#include <net/snmp.h>
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#include <net/sock.h>
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#include <net/xfrm.h>
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#include <net/sctp/sctp.h>
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#include <net/sctp/sm.h>
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#include <net/sctp/checksum.h>
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#include <net/net_namespace.h>
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/* Forward declarations for internal helpers. */
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static int sctp_rcv_ootb(struct sk_buff *);
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static struct sctp_association *__sctp_rcv_lookup(struct net *net,
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struct sk_buff *skb,
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const union sctp_addr *paddr,
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const union sctp_addr *laddr,
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struct sctp_transport **transportp);
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static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net,
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const union sctp_addr *laddr);
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static struct sctp_association *__sctp_lookup_association(
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struct net *net,
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const union sctp_addr *local,
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const union sctp_addr *peer,
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struct sctp_transport **pt);
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static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb);
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/* Calculate the SCTP checksum of an SCTP packet. */
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static inline int sctp_rcv_checksum(struct net *net, struct sk_buff *skb)
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{
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struct sctphdr *sh = sctp_hdr(skb);
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__le32 cmp = sh->checksum;
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__le32 val = sctp_compute_cksum(skb, 0);
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if (val != cmp) {
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/* CRC failure, dump it. */
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SCTP_INC_STATS_BH(net, SCTP_MIB_CHECKSUMERRORS);
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return -1;
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}
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return 0;
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}
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struct sctp_input_cb {
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union {
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struct inet_skb_parm h4;
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#if IS_ENABLED(CONFIG_IPV6)
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struct inet6_skb_parm h6;
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#endif
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} header;
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struct sctp_chunk *chunk;
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};
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#define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0]))
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/*
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* This is the routine which IP calls when receiving an SCTP packet.
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*/
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int sctp_rcv(struct sk_buff *skb)
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{
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struct sock *sk;
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struct sctp_association *asoc;
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struct sctp_endpoint *ep = NULL;
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struct sctp_ep_common *rcvr;
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struct sctp_transport *transport = NULL;
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struct sctp_chunk *chunk;
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struct sctphdr *sh;
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union sctp_addr src;
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union sctp_addr dest;
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int family;
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struct sctp_af *af;
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struct net *net = dev_net(skb->dev);
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if (skb->pkt_type != PACKET_HOST)
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goto discard_it;
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SCTP_INC_STATS_BH(net, SCTP_MIB_INSCTPPACKS);
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if (skb_linearize(skb))
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goto discard_it;
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sh = sctp_hdr(skb);
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/* Pull up the IP and SCTP headers. */
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__skb_pull(skb, skb_transport_offset(skb));
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if (skb->len < sizeof(struct sctphdr))
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goto discard_it;
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skb->csum_valid = 0; /* Previous value not applicable */
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if (skb_csum_unnecessary(skb))
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__skb_decr_checksum_unnecessary(skb);
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else if (!sctp_checksum_disable && sctp_rcv_checksum(net, skb) < 0)
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goto discard_it;
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skb->csum_valid = 1;
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skb_pull(skb, sizeof(struct sctphdr));
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/* Make sure we at least have chunk headers worth of data left. */
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if (skb->len < sizeof(struct sctp_chunkhdr))
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goto discard_it;
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family = ipver2af(ip_hdr(skb)->version);
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af = sctp_get_af_specific(family);
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if (unlikely(!af))
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goto discard_it;
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/* Initialize local addresses for lookups. */
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af->from_skb(&src, skb, 1);
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af->from_skb(&dest, skb, 0);
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/* If the packet is to or from a non-unicast address,
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* silently discard the packet.
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*
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* This is not clearly defined in the RFC except in section
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* 8.4 - OOTB handling. However, based on the book "Stream Control
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* Transmission Protocol" 2.1, "It is important to note that the
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* IP address of an SCTP transport address must be a routable
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* unicast address. In other words, IP multicast addresses and
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* IP broadcast addresses cannot be used in an SCTP transport
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* address."
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*/
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if (!af->addr_valid(&src, NULL, skb) ||
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!af->addr_valid(&dest, NULL, skb))
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goto discard_it;
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asoc = __sctp_rcv_lookup(net, skb, &src, &dest, &transport);
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if (!asoc)
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ep = __sctp_rcv_lookup_endpoint(net, &dest);
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/* Retrieve the common input handling substructure. */
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rcvr = asoc ? &asoc->base : &ep->base;
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sk = rcvr->sk;
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/*
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* If a frame arrives on an interface and the receiving socket is
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* bound to another interface, via SO_BINDTODEVICE, treat it as OOTB
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*/
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if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) {
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if (asoc) {
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sctp_association_put(asoc);
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asoc = NULL;
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} else {
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sctp_endpoint_put(ep);
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ep = NULL;
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}
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sk = net->sctp.ctl_sock;
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ep = sctp_sk(sk)->ep;
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sctp_endpoint_hold(ep);
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rcvr = &ep->base;
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}
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/*
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* RFC 2960, 8.4 - Handle "Out of the blue" Packets.
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* An SCTP packet is called an "out of the blue" (OOTB)
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* packet if it is correctly formed, i.e., passed the
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* receiver's checksum check, but the receiver is not
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* able to identify the association to which this
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* packet belongs.
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*/
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if (!asoc) {
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if (sctp_rcv_ootb(skb)) {
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SCTP_INC_STATS_BH(net, SCTP_MIB_OUTOFBLUES);
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goto discard_release;
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}
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}
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if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family))
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goto discard_release;
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nf_reset(skb);
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if (sk_filter(sk, skb))
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goto discard_release;
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/* Create an SCTP packet structure. */
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chunk = sctp_chunkify(skb, asoc, sk);
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if (!chunk)
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goto discard_release;
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SCTP_INPUT_CB(skb)->chunk = chunk;
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/* Remember what endpoint is to handle this packet. */
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chunk->rcvr = rcvr;
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/* Remember the SCTP header. */
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chunk->sctp_hdr = sh;
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/* Set the source and destination addresses of the incoming chunk. */
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sctp_init_addrs(chunk, &src, &dest);
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/* Remember where we came from. */
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chunk->transport = transport;
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/* Acquire access to the sock lock. Note: We are safe from other
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* bottom halves on this lock, but a user may be in the lock too,
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* so check if it is busy.
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*/
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bh_lock_sock(sk);
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if (sk != rcvr->sk) {
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/* Our cached sk is different from the rcvr->sk. This is
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* because migrate()/accept() may have moved the association
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* to a new socket and released all the sockets. So now we
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* are holding a lock on the old socket while the user may
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* be doing something with the new socket. Switch our veiw
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* of the current sk.
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*/
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bh_unlock_sock(sk);
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sk = rcvr->sk;
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bh_lock_sock(sk);
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}
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if (sock_owned_by_user(sk)) {
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if (sctp_add_backlog(sk, skb)) {
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bh_unlock_sock(sk);
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sctp_chunk_free(chunk);
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skb = NULL; /* sctp_chunk_free already freed the skb */
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goto discard_release;
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}
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SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_BACKLOG);
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} else {
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SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_SOFTIRQ);
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sctp_inq_push(&chunk->rcvr->inqueue, chunk);
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}
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bh_unlock_sock(sk);
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/* Release the asoc/ep ref we took in the lookup calls. */
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if (asoc)
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sctp_association_put(asoc);
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else
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sctp_endpoint_put(ep);
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return 0;
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discard_it:
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SCTP_INC_STATS_BH(net, SCTP_MIB_IN_PKT_DISCARDS);
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kfree_skb(skb);
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return 0;
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discard_release:
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/* Release the asoc/ep ref we took in the lookup calls. */
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if (asoc)
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sctp_association_put(asoc);
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else
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sctp_endpoint_put(ep);
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goto discard_it;
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}
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/* Process the backlog queue of the socket. Every skb on
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* the backlog holds a ref on an association or endpoint.
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* We hold this ref throughout the state machine to make
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* sure that the structure we need is still around.
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*/
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int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb)
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{
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struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
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struct sctp_inq *inqueue = &chunk->rcvr->inqueue;
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struct sctp_ep_common *rcvr = NULL;
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int backloged = 0;
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rcvr = chunk->rcvr;
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/* If the rcvr is dead then the association or endpoint
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* has been deleted and we can safely drop the chunk
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* and refs that we are holding.
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*/
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if (rcvr->dead) {
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sctp_chunk_free(chunk);
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goto done;
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}
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if (unlikely(rcvr->sk != sk)) {
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/* In this case, the association moved from one socket to
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* another. We are currently sitting on the backlog of the
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* old socket, so we need to move.
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* However, since we are here in the process context we
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* need to take make sure that the user doesn't own
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* the new socket when we process the packet.
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* If the new socket is user-owned, queue the chunk to the
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* backlog of the new socket without dropping any refs.
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* Otherwise, we can safely push the chunk on the inqueue.
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*/
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sk = rcvr->sk;
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bh_lock_sock(sk);
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if (sock_owned_by_user(sk)) {
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if (sk_add_backlog(sk, skb, sk->sk_rcvbuf))
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sctp_chunk_free(chunk);
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else
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backloged = 1;
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} else
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sctp_inq_push(inqueue, chunk);
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bh_unlock_sock(sk);
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/* If the chunk was backloged again, don't drop refs */
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if (backloged)
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return 0;
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} else {
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sctp_inq_push(inqueue, chunk);
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}
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done:
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/* Release the refs we took in sctp_add_backlog */
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if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
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sctp_association_put(sctp_assoc(rcvr));
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else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
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sctp_endpoint_put(sctp_ep(rcvr));
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else
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BUG();
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return 0;
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}
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static int sctp_add_backlog(struct sock *sk, struct sk_buff *skb)
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{
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struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk;
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struct sctp_ep_common *rcvr = chunk->rcvr;
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int ret;
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ret = sk_add_backlog(sk, skb, sk->sk_rcvbuf);
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if (!ret) {
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/* Hold the assoc/ep while hanging on the backlog queue.
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* This way, we know structures we need will not disappear
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* from us
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*/
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if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type)
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sctp_association_hold(sctp_assoc(rcvr));
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else if (SCTP_EP_TYPE_SOCKET == rcvr->type)
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sctp_endpoint_hold(sctp_ep(rcvr));
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else
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BUG();
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}
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return ret;
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}
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/* Handle icmp frag needed error. */
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void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc,
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struct sctp_transport *t, __u32 pmtu)
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{
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if (!t || (t->pathmtu <= pmtu))
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return;
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if (sock_owned_by_user(sk)) {
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asoc->pmtu_pending = 1;
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t->pmtu_pending = 1;
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return;
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}
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|
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if (t->param_flags & SPP_PMTUD_ENABLE) {
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/* Update transports view of the MTU */
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sctp_transport_update_pmtu(sk, t, pmtu);
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|
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/* Update association pmtu. */
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sctp_assoc_sync_pmtu(sk, asoc);
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}
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|
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/* Retransmit with the new pmtu setting.
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* Normally, if PMTU discovery is disabled, an ICMP Fragmentation
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* Needed will never be sent, but if a message was sent before
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* PMTU discovery was disabled that was larger than the PMTU, it
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* would not be fragmented, so it must be re-transmitted fragmented.
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*/
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sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD);
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}
|
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|
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void sctp_icmp_redirect(struct sock *sk, struct sctp_transport *t,
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struct sk_buff *skb)
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{
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struct dst_entry *dst;
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|
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if (!t)
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return;
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dst = sctp_transport_dst_check(t);
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if (dst)
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dst->ops->redirect(dst, sk, skb);
|
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}
|
|
|
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/*
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* SCTP Implementer's Guide, 2.37 ICMP handling procedures
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*
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* ICMP8) If the ICMP code is a "Unrecognized next header type encountered"
|
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* or a "Protocol Unreachable" treat this message as an abort
|
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* with the T bit set.
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*
|
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* This function sends an event to the state machine, which will abort the
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* association.
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*
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*/
|
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void sctp_icmp_proto_unreachable(struct sock *sk,
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struct sctp_association *asoc,
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struct sctp_transport *t)
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{
|
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if (sock_owned_by_user(sk)) {
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if (timer_pending(&t->proto_unreach_timer))
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return;
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else {
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if (!mod_timer(&t->proto_unreach_timer,
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jiffies + (HZ/20)))
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sctp_association_hold(asoc);
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}
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} else {
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struct net *net = sock_net(sk);
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|
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pr_debug("%s: unrecognized next header type "
|
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"encountered!\n", __func__);
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|
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if (del_timer(&t->proto_unreach_timer))
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sctp_association_put(asoc);
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|
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sctp_do_sm(net, SCTP_EVENT_T_OTHER,
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SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH),
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asoc->state, asoc->ep, asoc, t,
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GFP_ATOMIC);
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}
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}
|
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|
|
/* Common lookup code for icmp/icmpv6 error handler. */
|
|
struct sock *sctp_err_lookup(struct net *net, int family, struct sk_buff *skb,
|
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struct sctphdr *sctphdr,
|
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struct sctp_association **app,
|
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struct sctp_transport **tpp)
|
|
{
|
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union sctp_addr saddr;
|
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union sctp_addr daddr;
|
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struct sctp_af *af;
|
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struct sock *sk = NULL;
|
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struct sctp_association *asoc;
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struct sctp_transport *transport = NULL;
|
|
struct sctp_init_chunk *chunkhdr;
|
|
__u32 vtag = ntohl(sctphdr->vtag);
|
|
int len = skb->len - ((void *)sctphdr - (void *)skb->data);
|
|
|
|
*app = 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(net, &saddr, &daddr, &transport);
|
|
if (!asoc)
|
|
return NULL;
|
|
|
|
sk = asoc->base.sk;
|
|
|
|
/* RFC 4960, Appendix C. ICMP Handling
|
|
*
|
|
* ICMP6) An implementation MUST validate that the Verification Tag
|
|
* contained in the ICMP message matches the Verification Tag of
|
|
* the peer. If the Verification Tag is not 0 and does NOT
|
|
* match, discard the ICMP message. If it is 0 and the ICMP
|
|
* message contains enough bytes to verify that the chunk type is
|
|
* an INIT chunk and that the Initiate Tag matches the tag of the
|
|
* peer, continue with ICMP7. If the ICMP message is too short
|
|
* or the chunk type or the Initiate Tag does not match, silently
|
|
* discard the packet.
|
|
*/
|
|
if (vtag == 0) {
|
|
chunkhdr = (void *)sctphdr + sizeof(struct sctphdr);
|
|
if (len < sizeof(struct sctphdr) + sizeof(sctp_chunkhdr_t)
|
|
+ sizeof(__be32) ||
|
|
chunkhdr->chunk_hdr.type != SCTP_CID_INIT ||
|
|
ntohl(chunkhdr->init_hdr.init_tag) != asoc->c.my_vtag) {
|
|
goto out;
|
|
}
|
|
} else if (vtag != asoc->c.peer_vtag) {
|
|
goto out;
|
|
}
|
|
|
|
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(net, LINUX_MIB_LOCKDROPPEDICMPS);
|
|
|
|
*app = asoc;
|
|
*tpp = transport;
|
|
return sk;
|
|
|
|
out:
|
|
sctp_association_put(asoc);
|
|
return NULL;
|
|
}
|
|
|
|
/* Common cleanup code for icmp/icmpv6 error handler. */
|
|
void sctp_err_finish(struct sock *sk, struct sctp_association *asoc)
|
|
{
|
|
bh_unlock_sock(sk);
|
|
sctp_association_put(asoc);
|
|
}
|
|
|
|
/*
|
|
* 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)
|
|
{
|
|
const struct iphdr *iph = (const struct iphdr *)skb->data;
|
|
const int ihlen = iph->ihl * 4;
|
|
const int type = icmp_hdr(skb)->type;
|
|
const int code = icmp_hdr(skb)->code;
|
|
struct sock *sk;
|
|
struct sctp_association *asoc = NULL;
|
|
struct sctp_transport *transport;
|
|
struct inet_sock *inet;
|
|
__u16 saveip, savesctp;
|
|
int err;
|
|
struct net *net = dev_net(skb->dev);
|
|
|
|
/* Fix up skb to look at the embedded net header. */
|
|
saveip = skb->network_header;
|
|
savesctp = skb->transport_header;
|
|
skb_reset_network_header(skb);
|
|
skb_set_transport_header(skb, ihlen);
|
|
sk = sctp_err_lookup(net, AF_INET, skb, sctp_hdr(skb), &asoc, &transport);
|
|
/* Put back, the original values. */
|
|
skb->network_header = saveip;
|
|
skb->transport_header = savesctp;
|
|
if (!sk) {
|
|
ICMP_INC_STATS_BH(net, 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, 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;
|
|
case ICMP_REDIRECT:
|
|
sctp_icmp_redirect(sk, transport, skb);
|
|
/* Fall through to out_unlock. */
|
|
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, 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.
|
|
*/
|
|
static int sctp_rcv_ootb(struct sk_buff *skb)
|
|
{
|
|
sctp_chunkhdr_t *ch;
|
|
__u8 *ch_end;
|
|
|
|
ch = (sctp_chunkhdr_t *) skb->data;
|
|
|
|
/* Scan through all the chunks in the packet. */
|
|
do {
|
|
/* Break out if chunk length is less then minimal. */
|
|
if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
|
|
break;
|
|
|
|
ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
|
|
if (ch_end > skb_tail_pointer(skb))
|
|
break;
|
|
|
|
/* 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 4460, 2.11.2
|
|
* This will discard packets with INIT chunk bundled as
|
|
* subsequent chunks in the packet. When INIT is first,
|
|
* the normal INIT processing will discard the chunk.
|
|
*/
|
|
if (SCTP_CID_INIT == ch->type && (void *)ch != skb->data)
|
|
goto discard;
|
|
|
|
ch = (sctp_chunkhdr_t *) ch_end;
|
|
} while (ch_end < skb_tail_pointer(skb));
|
|
|
|
return 0;
|
|
|
|
discard:
|
|
return 1;
|
|
}
|
|
|
|
/* Insert endpoint into the hash table. */
|
|
static void __sctp_hash_endpoint(struct sctp_endpoint *ep)
|
|
{
|
|
struct net *net = sock_net(ep->base.sk);
|
|
struct sctp_ep_common *epb;
|
|
struct sctp_hashbucket *head;
|
|
|
|
epb = &ep->base;
|
|
|
|
epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port);
|
|
head = &sctp_ep_hashtable[epb->hashent];
|
|
|
|
write_lock(&head->lock);
|
|
hlist_add_head(&epb->node, &head->chain);
|
|
write_unlock(&head->lock);
|
|
}
|
|
|
|
/* Add an endpoint to the hash. Local BH-safe. */
|
|
void sctp_hash_endpoint(struct sctp_endpoint *ep)
|
|
{
|
|
local_bh_disable();
|
|
__sctp_hash_endpoint(ep);
|
|
local_bh_enable();
|
|
}
|
|
|
|
/* Remove endpoint from the hash table. */
|
|
static void __sctp_unhash_endpoint(struct sctp_endpoint *ep)
|
|
{
|
|
struct net *net = sock_net(ep->base.sk);
|
|
struct sctp_hashbucket *head;
|
|
struct sctp_ep_common *epb;
|
|
|
|
epb = &ep->base;
|
|
|
|
epb->hashent = sctp_ep_hashfn(net, epb->bind_addr.port);
|
|
|
|
head = &sctp_ep_hashtable[epb->hashent];
|
|
|
|
write_lock(&head->lock);
|
|
hlist_del_init(&epb->node);
|
|
write_unlock(&head->lock);
|
|
}
|
|
|
|
/* Remove endpoint from the hash. Local BH-safe. */
|
|
void sctp_unhash_endpoint(struct sctp_endpoint *ep)
|
|
{
|
|
local_bh_disable();
|
|
__sctp_unhash_endpoint(ep);
|
|
local_bh_enable();
|
|
}
|
|
|
|
/* Look up an endpoint. */
|
|
static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(struct net *net,
|
|
const union sctp_addr *laddr)
|
|
{
|
|
struct sctp_hashbucket *head;
|
|
struct sctp_ep_common *epb;
|
|
struct sctp_endpoint *ep;
|
|
int hash;
|
|
|
|
hash = sctp_ep_hashfn(net, ntohs(laddr->v4.sin_port));
|
|
head = &sctp_ep_hashtable[hash];
|
|
read_lock(&head->lock);
|
|
sctp_for_each_hentry(epb, &head->chain) {
|
|
ep = sctp_ep(epb);
|
|
if (sctp_endpoint_is_match(ep, net, laddr))
|
|
goto hit;
|
|
}
|
|
|
|
ep = sctp_sk(net->sctp.ctl_sock)->ep;
|
|
|
|
hit:
|
|
sctp_endpoint_hold(ep);
|
|
read_unlock(&head->lock);
|
|
return ep;
|
|
}
|
|
|
|
/* rhashtable for transport */
|
|
struct sctp_hash_cmp_arg {
|
|
const struct sctp_endpoint *ep;
|
|
const union sctp_addr *laddr;
|
|
const union sctp_addr *paddr;
|
|
const struct net *net;
|
|
};
|
|
|
|
static inline int sctp_hash_cmp(struct rhashtable_compare_arg *arg,
|
|
const void *ptr)
|
|
{
|
|
const struct sctp_hash_cmp_arg *x = arg->key;
|
|
const struct sctp_transport *t = ptr;
|
|
struct sctp_association *asoc = t->asoc;
|
|
const struct net *net = x->net;
|
|
|
|
if (!sctp_cmp_addr_exact(&t->ipaddr, x->paddr))
|
|
return 1;
|
|
if (!net_eq(sock_net(asoc->base.sk), net))
|
|
return 1;
|
|
if (x->ep) {
|
|
if (x->ep != asoc->ep)
|
|
return 1;
|
|
} else {
|
|
if (x->laddr->v4.sin_port != htons(asoc->base.bind_addr.port))
|
|
return 1;
|
|
if (!sctp_bind_addr_match(&asoc->base.bind_addr,
|
|
x->laddr, sctp_sk(asoc->base.sk)))
|
|
return 1;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static inline u32 sctp_hash_obj(const void *data, u32 len, u32 seed)
|
|
{
|
|
const struct sctp_transport *t = data;
|
|
const union sctp_addr *paddr = &t->ipaddr;
|
|
const struct net *net = sock_net(t->asoc->base.sk);
|
|
u16 lport = htons(t->asoc->base.bind_addr.port);
|
|
u32 addr;
|
|
|
|
if (paddr->sa.sa_family == AF_INET6)
|
|
addr = jhash(&paddr->v6.sin6_addr, 16, seed);
|
|
else
|
|
addr = paddr->v4.sin_addr.s_addr;
|
|
|
|
return jhash_3words(addr, ((__u32)paddr->v4.sin_port) << 16 |
|
|
(__force __u32)lport, net_hash_mix(net), seed);
|
|
}
|
|
|
|
static inline u32 sctp_hash_key(const void *data, u32 len, u32 seed)
|
|
{
|
|
const struct sctp_hash_cmp_arg *x = data;
|
|
const union sctp_addr *paddr = x->paddr;
|
|
const struct net *net = x->net;
|
|
u16 lport;
|
|
u32 addr;
|
|
|
|
lport = x->ep ? htons(x->ep->base.bind_addr.port) :
|
|
x->laddr->v4.sin_port;
|
|
if (paddr->sa.sa_family == AF_INET6)
|
|
addr = jhash(&paddr->v6.sin6_addr, 16, seed);
|
|
else
|
|
addr = paddr->v4.sin_addr.s_addr;
|
|
|
|
return jhash_3words(addr, ((__u32)paddr->v4.sin_port) << 16 |
|
|
(__force __u32)lport, net_hash_mix(net), seed);
|
|
}
|
|
|
|
static const struct rhashtable_params sctp_hash_params = {
|
|
.head_offset = offsetof(struct sctp_transport, node),
|
|
.hashfn = sctp_hash_key,
|
|
.obj_hashfn = sctp_hash_obj,
|
|
.obj_cmpfn = sctp_hash_cmp,
|
|
.automatic_shrinking = true,
|
|
};
|
|
|
|
int sctp_transport_hashtable_init(void)
|
|
{
|
|
return rhashtable_init(&sctp_transport_hashtable, &sctp_hash_params);
|
|
}
|
|
|
|
void sctp_transport_hashtable_destroy(void)
|
|
{
|
|
rhashtable_destroy(&sctp_transport_hashtable);
|
|
}
|
|
|
|
void sctp_hash_transport(struct sctp_transport *t)
|
|
{
|
|
struct sctp_hash_cmp_arg arg;
|
|
|
|
if (t->asoc->temp)
|
|
return;
|
|
|
|
arg.ep = t->asoc->ep;
|
|
arg.paddr = &t->ipaddr;
|
|
arg.net = sock_net(t->asoc->base.sk);
|
|
|
|
reinsert:
|
|
if (rhashtable_lookup_insert_key(&sctp_transport_hashtable, &arg,
|
|
&t->node, sctp_hash_params) == -EBUSY)
|
|
goto reinsert;
|
|
}
|
|
|
|
void sctp_unhash_transport(struct sctp_transport *t)
|
|
{
|
|
if (t->asoc->temp)
|
|
return;
|
|
|
|
rhashtable_remove_fast(&sctp_transport_hashtable, &t->node,
|
|
sctp_hash_params);
|
|
}
|
|
|
|
struct sctp_transport *sctp_addrs_lookup_transport(
|
|
struct net *net,
|
|
const union sctp_addr *laddr,
|
|
const union sctp_addr *paddr)
|
|
{
|
|
struct sctp_hash_cmp_arg arg = {
|
|
.ep = NULL,
|
|
.laddr = laddr,
|
|
.paddr = paddr,
|
|
.net = net,
|
|
};
|
|
|
|
return rhashtable_lookup_fast(&sctp_transport_hashtable, &arg,
|
|
sctp_hash_params);
|
|
}
|
|
|
|
struct sctp_transport *sctp_epaddr_lookup_transport(
|
|
const struct sctp_endpoint *ep,
|
|
const union sctp_addr *paddr)
|
|
{
|
|
struct net *net = sock_net(ep->base.sk);
|
|
struct sctp_hash_cmp_arg arg = {
|
|
.ep = ep,
|
|
.paddr = paddr,
|
|
.net = net,
|
|
};
|
|
|
|
return rhashtable_lookup_fast(&sctp_transport_hashtable, &arg,
|
|
sctp_hash_params);
|
|
}
|
|
|
|
/* Look up an association. */
|
|
static struct sctp_association *__sctp_lookup_association(
|
|
struct net *net,
|
|
const union sctp_addr *local,
|
|
const union sctp_addr *peer,
|
|
struct sctp_transport **pt)
|
|
{
|
|
struct sctp_transport *t;
|
|
struct sctp_association *asoc = NULL;
|
|
|
|
t = sctp_addrs_lookup_transport(net, local, peer);
|
|
if (!t || !sctp_transport_hold(t))
|
|
goto out;
|
|
|
|
asoc = t->asoc;
|
|
sctp_association_hold(asoc);
|
|
*pt = t;
|
|
|
|
sctp_transport_put(t);
|
|
|
|
out:
|
|
return asoc;
|
|
}
|
|
|
|
/* Look up an association. protected by RCU read lock */
|
|
static
|
|
struct sctp_association *sctp_lookup_association(struct net *net,
|
|
const union sctp_addr *laddr,
|
|
const union sctp_addr *paddr,
|
|
struct sctp_transport **transportp)
|
|
{
|
|
struct sctp_association *asoc;
|
|
|
|
rcu_read_lock();
|
|
asoc = __sctp_lookup_association(net, laddr, paddr, transportp);
|
|
rcu_read_unlock();
|
|
|
|
return asoc;
|
|
}
|
|
|
|
/* Is there an association matching the given local and peer addresses? */
|
|
int sctp_has_association(struct net *net,
|
|
const union sctp_addr *laddr,
|
|
const union sctp_addr *paddr)
|
|
{
|
|
struct sctp_association *asoc;
|
|
struct sctp_transport *transport;
|
|
|
|
if ((asoc = sctp_lookup_association(net, laddr, paddr, &transport))) {
|
|
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 net *net,
|
|
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 = sctp_hdr(skb);
|
|
union sctp_params params;
|
|
sctp_init_chunk_t *init;
|
|
struct sctp_transport *transport;
|
|
struct sctp_af *af;
|
|
|
|
/*
|
|
* 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, sh->source, 0);
|
|
|
|
asoc = __sctp_lookup_association(net, laddr, paddr, &transport);
|
|
if (asoc)
|
|
return asoc;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
/* ADD-IP, Section 5.2
|
|
* When an endpoint receives an ASCONF Chunk from the remote peer
|
|
* special procedures may be needed to identify the association the
|
|
* ASCONF Chunk is associated with. To properly find the association
|
|
* the following procedures SHOULD be followed:
|
|
*
|
|
* D2) If the association is not found, use the address found in the
|
|
* Address Parameter TLV combined with the port number found in the
|
|
* SCTP common header. If found proceed to rule D4.
|
|
*
|
|
* D2-ext) If more than one ASCONF Chunks are packed together, use the
|
|
* address found in the ASCONF Address Parameter TLV of each of the
|
|
* subsequent ASCONF Chunks. If found, proceed to rule D4.
|
|
*/
|
|
static struct sctp_association *__sctp_rcv_asconf_lookup(
|
|
struct net *net,
|
|
sctp_chunkhdr_t *ch,
|
|
const union sctp_addr *laddr,
|
|
__be16 peer_port,
|
|
struct sctp_transport **transportp)
|
|
{
|
|
sctp_addip_chunk_t *asconf = (struct sctp_addip_chunk *)ch;
|
|
struct sctp_af *af;
|
|
union sctp_addr_param *param;
|
|
union sctp_addr paddr;
|
|
|
|
/* Skip over the ADDIP header and find the Address parameter */
|
|
param = (union sctp_addr_param *)(asconf + 1);
|
|
|
|
af = sctp_get_af_specific(param_type2af(param->p.type));
|
|
if (unlikely(!af))
|
|
return NULL;
|
|
|
|
af->from_addr_param(&paddr, param, peer_port, 0);
|
|
|
|
return __sctp_lookup_association(net, laddr, &paddr, transportp);
|
|
}
|
|
|
|
|
|
/* SCTP-AUTH, Section 6.3:
|
|
* If the receiver does not find a STCB for a packet containing an AUTH
|
|
* chunk as the first chunk and not a COOKIE-ECHO chunk as the second
|
|
* chunk, it MUST use the chunks after the AUTH chunk to look up an existing
|
|
* association.
|
|
*
|
|
* This means that any chunks that can help us identify the association need
|
|
* to be looked at to find this association.
|
|
*/
|
|
static struct sctp_association *__sctp_rcv_walk_lookup(struct net *net,
|
|
struct sk_buff *skb,
|
|
const union sctp_addr *laddr,
|
|
struct sctp_transport **transportp)
|
|
{
|
|
struct sctp_association *asoc = NULL;
|
|
sctp_chunkhdr_t *ch;
|
|
int have_auth = 0;
|
|
unsigned int chunk_num = 1;
|
|
__u8 *ch_end;
|
|
|
|
/* Walk through the chunks looking for AUTH or ASCONF chunks
|
|
* to help us find the association.
|
|
*/
|
|
ch = (sctp_chunkhdr_t *) skb->data;
|
|
do {
|
|
/* Break out if chunk length is less then minimal. */
|
|
if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t))
|
|
break;
|
|
|
|
ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length));
|
|
if (ch_end > skb_tail_pointer(skb))
|
|
break;
|
|
|
|
switch (ch->type) {
|
|
case SCTP_CID_AUTH:
|
|
have_auth = chunk_num;
|
|
break;
|
|
|
|
case SCTP_CID_COOKIE_ECHO:
|
|
/* If a packet arrives containing an AUTH chunk as
|
|
* a first chunk, a COOKIE-ECHO chunk as the second
|
|
* chunk, and possibly more chunks after them, and
|
|
* the receiver does not have an STCB for that
|
|
* packet, then authentication is based on
|
|
* the contents of the COOKIE- ECHO chunk.
|
|
*/
|
|
if (have_auth == 1 && chunk_num == 2)
|
|
return NULL;
|
|
break;
|
|
|
|
case SCTP_CID_ASCONF:
|
|
if (have_auth || net->sctp.addip_noauth)
|
|
asoc = __sctp_rcv_asconf_lookup(
|
|
net, ch, laddr,
|
|
sctp_hdr(skb)->source,
|
|
transportp);
|
|
default:
|
|
break;
|
|
}
|
|
|
|
if (asoc)
|
|
break;
|
|
|
|
ch = (sctp_chunkhdr_t *) ch_end;
|
|
chunk_num++;
|
|
} while (ch_end < skb_tail_pointer(skb));
|
|
|
|
return asoc;
|
|
}
|
|
|
|
/*
|
|
* There are circumstances when we need to look inside the SCTP packet
|
|
* for information to help us find the association. Examples
|
|
* include looking inside of INIT/INIT-ACK chunks or after the AUTH
|
|
* chunks.
|
|
*/
|
|
static struct sctp_association *__sctp_rcv_lookup_harder(struct net *net,
|
|
struct sk_buff *skb,
|
|
const union sctp_addr *laddr,
|
|
struct sctp_transport **transportp)
|
|
{
|
|
sctp_chunkhdr_t *ch;
|
|
|
|
ch = (sctp_chunkhdr_t *) skb->data;
|
|
|
|
/* 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;
|
|
|
|
/* If this is INIT/INIT-ACK look inside the chunk too. */
|
|
if (ch->type == SCTP_CID_INIT || ch->type == SCTP_CID_INIT_ACK)
|
|
return __sctp_rcv_init_lookup(net, skb, laddr, transportp);
|
|
|
|
return __sctp_rcv_walk_lookup(net, skb, laddr, transportp);
|
|
}
|
|
|
|
/* Lookup an association for an inbound skb. */
|
|
static struct sctp_association *__sctp_rcv_lookup(struct net *net,
|
|
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(net, 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_lookup_harder(net, skb, laddr, transportp);
|
|
|
|
return asoc;
|
|
}
|