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![Daniel Borkmann](/assets/img/avatar_default.png)
Be more precise in transport path selection and use ktime helpers instead of jiffies to compare and pick the better primary and secondary recently used transports. This also avoids any side-effects during a possible roll-over, and could lead to better path decision-making. Signed-off-by: Daniel Borkmann <dborkman@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
501 lines
13 KiB
C
501 lines
13 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) 2001-2002 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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* This abstraction represents an SCTP endpoint.
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*
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* The 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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* The 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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* Jon Grimm <jgrimm@austin.ibm.com>
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* Daisy Chang <daisyc@us.ibm.com>
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* Dajiang Zhang <dajiang.zhang@nokia.com>
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*/
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#include <linux/types.h>
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#include <linux/slab.h>
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#include <linux/in.h>
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#include <linux/random.h> /* get_random_bytes() */
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#include <linux/crypto.h>
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#include <net/sock.h>
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#include <net/ipv6.h>
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#include <net/sctp/sctp.h>
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#include <net/sctp/sm.h>
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/* Forward declarations for internal helpers. */
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static void sctp_endpoint_bh_rcv(struct work_struct *work);
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/*
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* Initialize the base fields of the endpoint structure.
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*/
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static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
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struct sock *sk,
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gfp_t gfp)
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{
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struct net *net = sock_net(sk);
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struct sctp_hmac_algo_param *auth_hmacs = NULL;
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struct sctp_chunks_param *auth_chunks = NULL;
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struct sctp_shared_key *null_key;
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int err;
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ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp);
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if (!ep->digest)
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return NULL;
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ep->auth_enable = net->sctp.auth_enable;
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if (ep->auth_enable) {
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/* Allocate space for HMACS and CHUNKS authentication
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* variables. There are arrays that we encode directly
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* into parameters to make the rest of the operations easier.
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*/
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auth_hmacs = kzalloc(sizeof(sctp_hmac_algo_param_t) +
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sizeof(__u16) * SCTP_AUTH_NUM_HMACS, gfp);
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if (!auth_hmacs)
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goto nomem;
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auth_chunks = kzalloc(sizeof(sctp_chunks_param_t) +
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SCTP_NUM_CHUNK_TYPES, gfp);
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if (!auth_chunks)
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goto nomem;
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/* Initialize the HMACS parameter.
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* SCTP-AUTH: Section 3.3
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* Every endpoint supporting SCTP chunk authentication MUST
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* support the HMAC based on the SHA-1 algorithm.
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*/
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auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO;
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auth_hmacs->param_hdr.length =
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htons(sizeof(sctp_paramhdr_t) + 2);
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auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1);
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/* Initialize the CHUNKS parameter */
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auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS;
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auth_chunks->param_hdr.length = htons(sizeof(sctp_paramhdr_t));
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/* If the Add-IP functionality is enabled, we must
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* authenticate, ASCONF and ASCONF-ACK chunks
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*/
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if (net->sctp.addip_enable) {
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auth_chunks->chunks[0] = SCTP_CID_ASCONF;
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auth_chunks->chunks[1] = SCTP_CID_ASCONF_ACK;
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auth_chunks->param_hdr.length =
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htons(sizeof(sctp_paramhdr_t) + 2);
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}
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}
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/* Initialize the base structure. */
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/* What type of endpoint are we? */
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ep->base.type = SCTP_EP_TYPE_SOCKET;
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/* Initialize the basic object fields. */
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atomic_set(&ep->base.refcnt, 1);
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ep->base.dead = false;
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/* Create an input queue. */
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sctp_inq_init(&ep->base.inqueue);
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/* Set its top-half handler */
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sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv);
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/* Initialize the bind addr area */
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sctp_bind_addr_init(&ep->base.bind_addr, 0);
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/* Remember who we are attached to. */
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ep->base.sk = sk;
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sock_hold(ep->base.sk);
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/* Create the lists of associations. */
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INIT_LIST_HEAD(&ep->asocs);
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/* Use SCTP specific send buffer space queues. */
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ep->sndbuf_policy = net->sctp.sndbuf_policy;
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sk->sk_data_ready = sctp_data_ready;
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sk->sk_write_space = sctp_write_space;
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sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
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/* Get the receive buffer policy for this endpoint */
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ep->rcvbuf_policy = net->sctp.rcvbuf_policy;
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/* Initialize the secret key used with cookie. */
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get_random_bytes(ep->secret_key, sizeof(ep->secret_key));
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/* SCTP-AUTH extensions*/
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INIT_LIST_HEAD(&ep->endpoint_shared_keys);
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null_key = sctp_auth_shkey_create(0, gfp);
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if (!null_key)
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goto nomem;
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list_add(&null_key->key_list, &ep->endpoint_shared_keys);
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/* Allocate and initialize transorms arrays for supported HMACs. */
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err = sctp_auth_init_hmacs(ep, gfp);
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if (err)
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goto nomem_hmacs;
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/* Add the null key to the endpoint shared keys list and
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* set the hmcas and chunks pointers.
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*/
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ep->auth_hmacs_list = auth_hmacs;
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ep->auth_chunk_list = auth_chunks;
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return ep;
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nomem_hmacs:
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sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
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nomem:
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/* Free all allocations */
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kfree(auth_hmacs);
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kfree(auth_chunks);
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kfree(ep->digest);
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return NULL;
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}
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/* Create a sctp_endpoint with all that boring stuff initialized.
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* Returns NULL if there isn't enough memory.
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*/
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struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
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{
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struct sctp_endpoint *ep;
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/* Build a local endpoint. */
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ep = kzalloc(sizeof(*ep), gfp);
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if (!ep)
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goto fail;
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if (!sctp_endpoint_init(ep, sk, gfp))
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goto fail_init;
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SCTP_DBG_OBJCNT_INC(ep);
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return ep;
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fail_init:
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kfree(ep);
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fail:
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return NULL;
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}
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/* Add an association to an endpoint. */
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void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
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struct sctp_association *asoc)
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{
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struct sock *sk = ep->base.sk;
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/* If this is a temporary association, don't bother
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* since we'll be removing it shortly and don't
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* want anyone to find it anyway.
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*/
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if (asoc->temp)
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return;
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/* Now just add it to our list of asocs */
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list_add_tail(&asoc->asocs, &ep->asocs);
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/* Increment the backlog value for a TCP-style listening socket. */
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if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
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sk->sk_ack_backlog++;
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}
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/* Free the endpoint structure. Delay cleanup until
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* all users have released their reference count on this structure.
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*/
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void sctp_endpoint_free(struct sctp_endpoint *ep)
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{
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ep->base.dead = true;
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ep->base.sk->sk_state = SCTP_SS_CLOSED;
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/* Unlink this endpoint, so we can't find it again! */
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sctp_unhash_endpoint(ep);
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sctp_endpoint_put(ep);
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}
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/* Final destructor for endpoint. */
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static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
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{
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struct sock *sk;
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if (unlikely(!ep->base.dead)) {
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WARN(1, "Attempt to destroy undead endpoint %p!\n", ep);
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return;
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}
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/* Free the digest buffer */
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kfree(ep->digest);
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/* SCTP-AUTH: Free up AUTH releated data such as shared keys
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* chunks and hmacs arrays that were allocated
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*/
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sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
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kfree(ep->auth_hmacs_list);
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kfree(ep->auth_chunk_list);
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/* AUTH - Free any allocated HMAC transform containers */
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sctp_auth_destroy_hmacs(ep->auth_hmacs);
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/* Cleanup. */
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sctp_inq_free(&ep->base.inqueue);
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sctp_bind_addr_free(&ep->base.bind_addr);
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memset(ep->secret_key, 0, sizeof(ep->secret_key));
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/* Give up our hold on the sock. */
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sk = ep->base.sk;
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if (sk != NULL) {
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/* Remove and free the port */
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if (sctp_sk(sk)->bind_hash)
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sctp_put_port(sk);
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sock_put(sk);
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}
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kfree(ep);
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SCTP_DBG_OBJCNT_DEC(ep);
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}
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/* Hold a reference to an endpoint. */
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void sctp_endpoint_hold(struct sctp_endpoint *ep)
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{
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atomic_inc(&ep->base.refcnt);
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}
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/* Release a reference to an endpoint and clean up if there are
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* no more references.
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*/
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void sctp_endpoint_put(struct sctp_endpoint *ep)
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{
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if (atomic_dec_and_test(&ep->base.refcnt))
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sctp_endpoint_destroy(ep);
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}
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/* Is this the endpoint we are looking for? */
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struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
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struct net *net,
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const union sctp_addr *laddr)
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{
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struct sctp_endpoint *retval = NULL;
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if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) &&
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net_eq(sock_net(ep->base.sk), net)) {
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if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
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sctp_sk(ep->base.sk)))
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retval = ep;
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}
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return retval;
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}
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/* Find the association that goes with this chunk.
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* We do a linear search of the associations for this endpoint.
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* We return the matching transport address too.
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*/
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static struct sctp_association *__sctp_endpoint_lookup_assoc(
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const struct sctp_endpoint *ep,
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const union sctp_addr *paddr,
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struct sctp_transport **transport)
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{
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struct sctp_association *asoc = NULL;
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struct sctp_association *tmp;
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struct sctp_transport *t = NULL;
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struct sctp_hashbucket *head;
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struct sctp_ep_common *epb;
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int hash;
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int rport;
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*transport = NULL;
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/* If the local port is not set, there can't be any associations
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* on this endpoint.
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*/
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if (!ep->base.bind_addr.port)
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goto out;
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rport = ntohs(paddr->v4.sin_port);
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hash = sctp_assoc_hashfn(sock_net(ep->base.sk), ep->base.bind_addr.port,
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rport);
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head = &sctp_assoc_hashtable[hash];
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read_lock(&head->lock);
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sctp_for_each_hentry(epb, &head->chain) {
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tmp = sctp_assoc(epb);
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if (tmp->ep != ep || rport != tmp->peer.port)
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continue;
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t = sctp_assoc_lookup_paddr(tmp, paddr);
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if (t) {
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asoc = tmp;
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*transport = t;
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break;
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}
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}
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read_unlock(&head->lock);
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out:
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return asoc;
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}
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/* Lookup association on an endpoint based on a peer address. BH-safe. */
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struct sctp_association *sctp_endpoint_lookup_assoc(
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const struct sctp_endpoint *ep,
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const union sctp_addr *paddr,
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struct sctp_transport **transport)
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{
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struct sctp_association *asoc;
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local_bh_disable();
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asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport);
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local_bh_enable();
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return asoc;
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}
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/* Look for any peeled off association from the endpoint that matches the
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* given peer address.
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*/
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int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
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const union sctp_addr *paddr)
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{
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struct sctp_sockaddr_entry *addr;
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struct sctp_bind_addr *bp;
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struct net *net = sock_net(ep->base.sk);
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bp = &ep->base.bind_addr;
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/* This function is called with the socket lock held,
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* so the address_list can not change.
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*/
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list_for_each_entry(addr, &bp->address_list, list) {
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if (sctp_has_association(net, &addr->a, paddr))
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return 1;
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}
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return 0;
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}
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/* Do delayed input processing. This is scheduled by sctp_rcv().
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* This may be called on BH or task time.
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*/
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static void sctp_endpoint_bh_rcv(struct work_struct *work)
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{
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struct sctp_endpoint *ep =
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container_of(work, struct sctp_endpoint,
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base.inqueue.immediate);
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struct sctp_association *asoc;
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struct sock *sk;
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struct net *net;
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struct sctp_transport *transport;
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struct sctp_chunk *chunk;
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struct sctp_inq *inqueue;
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sctp_subtype_t subtype;
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sctp_state_t state;
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int error = 0;
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int first_time = 1; /* is this the first time through the loop */
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if (ep->base.dead)
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return;
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asoc = NULL;
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inqueue = &ep->base.inqueue;
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sk = ep->base.sk;
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net = sock_net(sk);
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while (NULL != (chunk = sctp_inq_pop(inqueue))) {
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subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
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/* If the first chunk in the packet is AUTH, do special
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* processing specified in Section 6.3 of SCTP-AUTH spec
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*/
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if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
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struct sctp_chunkhdr *next_hdr;
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next_hdr = sctp_inq_peek(inqueue);
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if (!next_hdr)
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goto normal;
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/* If the next chunk is COOKIE-ECHO, skip the AUTH
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* chunk while saving a pointer to it so we can do
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* Authentication later (during cookie-echo
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* processing).
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*/
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if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
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chunk->auth_chunk = skb_clone(chunk->skb,
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GFP_ATOMIC);
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chunk->auth = 1;
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continue;
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}
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}
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normal:
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/* We might have grown an association since last we
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* looked, so try again.
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*
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* This happens when we've just processed our
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* COOKIE-ECHO chunk.
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*/
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if (NULL == chunk->asoc) {
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asoc = sctp_endpoint_lookup_assoc(ep,
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sctp_source(chunk),
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&transport);
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chunk->asoc = asoc;
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chunk->transport = transport;
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}
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state = asoc ? asoc->state : SCTP_STATE_CLOSED;
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if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
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continue;
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/* Remember where the last DATA chunk came from so we
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* know where to send the SACK.
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*/
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if (asoc && sctp_chunk_is_data(chunk))
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asoc->peer.last_data_from = chunk->transport;
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else {
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SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
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if (asoc)
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asoc->stats.ictrlchunks++;
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}
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if (chunk->transport)
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chunk->transport->last_time_heard = ktime_get();
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error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
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ep, asoc, chunk, GFP_ATOMIC);
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if (error && chunk)
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chunk->pdiscard = 1;
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/* Check to see if the endpoint is freed in response to
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* the incoming chunk. If so, get out of the while loop.
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*/
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if (!sctp_sk(sk)->ep)
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break;
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if (first_time)
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first_time = 0;
|
|
}
|
|
}
|