151ec796a2
Currently, if the immutable algorithm like bsearch or radix_lockless receives rtable update notification, it schedules algorithm rebuild. This rebuild is executed by the callout after ~50 milliseconds. It is possible that a script adding an interface address and than route with the gateway bound to that address will fail. It can happen due to the fact that fib is not updated by the time the route addition request arrives. Fix this by allowing synchronous algorithm rebuilds based on certain conditions. By default, these conditions assume: 1) less than net.route.algo.fib_sync_limit=100 routes 2) routes without gateway. * Move algo instance build entirely under rib WLOCK. Rib lock is only used for control plane (except radix algo, but there are no rebuilds). * Add rib_walk_ext_locked() function to allow RIB iteration with rib lock already held. * Fix rare potential callout use-after-free for fds by binding fd callout to the relevant rib rmlock. In that case, callout_stop() under rib WLOCK guarantees no callout will be executed afterwards. MFC after: 3 days
386 lines
10 KiB
C
386 lines
10 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2020 Alexander V. Chernikov
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "opt_inet.h"
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#include "opt_inet6.h"
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#include "opt_route.h"
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#include <sys/param.h>
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#include <sys/jail.h>
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#include <sys/systm.h>
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#include <sys/malloc.h>
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#include <sys/mbuf.h>
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#include <sys/socket.h>
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#include <sys/sysctl.h>
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#include <sys/syslog.h>
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#include <sys/sysproto.h>
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#include <sys/proc.h>
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#include <sys/domain.h>
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#include <sys/kernel.h>
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#include <sys/lock.h>
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#include <sys/rmlock.h>
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#include <net/if.h>
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#include <net/if_var.h>
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#include <net/if_dl.h>
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#include <net/route.h>
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#include <net/route/route_ctl.h>
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#include <net/route/route_var.h>
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#include <net/route/nhop_utils.h>
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#include <net/route/nhop.h>
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#include <net/route/nhop_var.h>
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#ifdef INET
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#include <netinet/in_fib.h>
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#endif
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#ifdef INET6
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#include <netinet6/in6_fib.h>
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#endif
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#include <net/vnet.h>
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/*
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* RIB helper functions.
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*/
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void
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rib_walk_ext_locked(struct rib_head *rnh, rib_walktree_f_t *wa_f,
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rib_walk_hook_f_t *hook_f, void *arg)
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{
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if (hook_f != NULL)
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hook_f(rnh, RIB_WALK_HOOK_PRE, arg);
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rnh->rnh_walktree(&rnh->head, (walktree_f_t *)wa_f, arg);
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if (hook_f != NULL)
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hook_f(rnh, RIB_WALK_HOOK_POST, arg);
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}
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/*
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* Calls @wa_f with @arg for each entry in the table specified by
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* @af and @fibnum.
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*
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* @ss_t callback is called before and after the tree traversal
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* while holding table lock.
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*
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* Table is traversed under read lock unless @wlock is set.
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*/
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void
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rib_walk_ext_internal(struct rib_head *rnh, bool wlock, rib_walktree_f_t *wa_f,
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rib_walk_hook_f_t *hook_f, void *arg)
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{
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RIB_RLOCK_TRACKER;
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if (wlock)
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RIB_WLOCK(rnh);
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else
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RIB_RLOCK(rnh);
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rib_walk_ext_locked(rnh, wa_f, hook_f, arg);
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if (wlock)
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RIB_WUNLOCK(rnh);
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else
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RIB_RUNLOCK(rnh);
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}
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void
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rib_walk_ext(uint32_t fibnum, int family, bool wlock, rib_walktree_f_t *wa_f,
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rib_walk_hook_f_t *hook_f, void *arg)
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{
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struct rib_head *rnh;
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if ((rnh = rt_tables_get_rnh(fibnum, family)) != NULL)
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rib_walk_ext_internal(rnh, wlock, wa_f, hook_f, arg);
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}
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/*
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* Calls @wa_f with @arg for each entry in the table specified by
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* @af and @fibnum.
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*
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* Table is traversed under read lock unless @wlock is set.
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*/
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void
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rib_walk(uint32_t fibnum, int family, bool wlock, rib_walktree_f_t *wa_f,
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void *arg)
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{
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rib_walk_ext(fibnum, family, wlock, wa_f, NULL, arg);
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}
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/*
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* Iterates over all existing fibs in system calling
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* @hook_f function before/after traversing each fib.
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* Calls @wa_f function for each element in current fib.
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* If af is not AF_UNSPEC, iterates over fibs in particular
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* address family.
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*/
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void
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rib_foreach_table_walk(int family, bool wlock, rib_walktree_f_t *wa_f,
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rib_walk_hook_f_t *hook_f, void *arg)
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{
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for (uint32_t fibnum = 0; fibnum < rt_numfibs; fibnum++) {
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/* Do we want some specific family? */
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if (family != AF_UNSPEC) {
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rib_walk_ext(fibnum, family, wlock, wa_f, hook_f, arg);
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continue;
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}
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for (int i = 1; i <= AF_MAX; i++)
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rib_walk_ext(fibnum, i, wlock, wa_f, hook_f, arg);
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}
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}
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/*
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* Iterates over all existing fibs in system and deletes each element
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* for which @filter_f function returns non-zero value.
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* If @family is not AF_UNSPEC, iterates over fibs in particular
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* address family.
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*/
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void
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rib_foreach_table_walk_del(int family, rib_filter_f_t *filter_f, void *arg)
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{
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for (uint32_t fibnum = 0; fibnum < rt_numfibs; fibnum++) {
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/* Do we want some specific family? */
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if (family != AF_UNSPEC) {
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rib_walk_del(fibnum, family, filter_f, arg, 0);
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continue;
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}
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for (int i = 1; i <= AF_MAX; i++)
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rib_walk_del(fibnum, i, filter_f, arg, 0);
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}
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}
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/*
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* Wrapper for the control plane functions for performing af-agnostic
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* lookups.
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* @fibnum: fib to perform the lookup.
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* @dst: sockaddr with family and addr filled in. IPv6 addresses needs to be in
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* deembedded from.
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* @flags: fib(9) flags.
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* @flowid: flow id for path selection in multipath use case.
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*
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* Returns nhop_object or NULL.
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*
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* Requires NET_EPOCH.
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*
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*/
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struct nhop_object *
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rib_lookup(uint32_t fibnum, const struct sockaddr *dst, uint32_t flags,
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uint32_t flowid)
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{
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struct nhop_object *nh;
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nh = NULL;
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switch (dst->sa_family) {
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#ifdef INET
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case AF_INET:
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{
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const struct sockaddr_in *a = (const struct sockaddr_in *)dst;
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nh = fib4_lookup(fibnum, a->sin_addr, 0, flags, flowid);
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break;
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}
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#endif
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#ifdef INET6
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case AF_INET6:
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{
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const struct sockaddr_in6 *a = (const struct sockaddr_in6*)dst;
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nh = fib6_lookup(fibnum, &a->sin6_addr, a->sin6_scope_id,
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flags, flowid);
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break;
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}
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#endif
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}
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return (nh);
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}
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#ifdef ROUTE_MPATH
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static void
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decompose_change_notification(struct rib_cmd_info *rc, route_notification_t *cb,
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void *cbdata)
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{
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uint32_t num_old, num_new;
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uint32_t nh_idx_old, nh_idx_new;
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struct weightened_nhop *wn_old, *wn_new;
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struct weightened_nhop tmp = { NULL, 0 };
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uint32_t idx_old = 0, idx_new = 0;
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struct rib_cmd_info rc_del = { .rc_cmd = RTM_DELETE, .rc_rt = rc->rc_rt };
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struct rib_cmd_info rc_add = { .rc_cmd = RTM_ADD, .rc_rt = rc->rc_rt };
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if (NH_IS_NHGRP(rc->rc_nh_old)) {
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wn_old = nhgrp_get_nhops((struct nhgrp_object *)rc->rc_nh_old, &num_old);
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} else {
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tmp.nh = rc->rc_nh_old;
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tmp.weight = rc->rc_nh_weight;
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wn_old = &tmp;
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num_old = 1;
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}
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if (NH_IS_NHGRP(rc->rc_nh_new)) {
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wn_new = nhgrp_get_nhops((struct nhgrp_object *)rc->rc_nh_new, &num_new);
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} else {
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tmp.nh = rc->rc_nh_new;
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tmp.weight = rc->rc_nh_weight;
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wn_new = &tmp;
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num_new = 1;
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}
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/* Use the fact that each @wn array is sorted */
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/*
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* Want to convert into set of add and delete operations
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* [1] -> [1, 2] = A{2}
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* [2] -> [1, 2] = A{1}
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* [1, 2, 4]->[1, 3, 4] = A{2}, D{3}
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* [1, 2, 4]->[1, 4] = D{2}
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* [1, 2, 4] -> [3, 4] = D{1}, C{2,3} OR C{1,3}, D{2} OR D{1},D{2},A{3}
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* [1, 2] -> [3, 4] =
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*
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*/
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idx_old = 0;
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while ((idx_old < num_old) && (idx_new < num_new)) {
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nh_idx_old = wn_old[idx_old].nh->nh_priv->nh_idx;
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nh_idx_new = wn_new[idx_new].nh->nh_priv->nh_idx;
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if (nh_idx_old == nh_idx_new) {
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if (wn_old[idx_old].weight != wn_new[idx_new].weight) {
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/* Update weight by providing del/add notifications */
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rc_del.rc_nh_old = wn_old[idx_old].nh;
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rc_del.rc_nh_weight = wn_old[idx_old].weight;
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cb(&rc_del, cbdata);
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rc_add.rc_nh_new = wn_new[idx_new].nh;
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rc_add.rc_nh_weight = wn_new[idx_new].weight;
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cb(&rc_add, cbdata);
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}
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idx_old++;
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idx_new++;
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} else if (nh_idx_old < nh_idx_new) {
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/*
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* [1, ~2~, 4], [1, ~3~, 4]
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* [1, ~2~, 5], [1, ~3~, 4]
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* [1, ~2~], [1, ~3~, 4]
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*/
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if ((idx_old + 1 >= num_old) ||
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(wn_old[idx_old + 1].nh->nh_priv->nh_idx > nh_idx_new)) {
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/* Add new unless the next old item is still <= new */
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rc_add.rc_nh_new = wn_new[idx_new].nh;
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rc_add.rc_nh_weight = wn_new[idx_new].weight;
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cb(&rc_add, cbdata);
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idx_new++;
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}
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/* In any case, delete current old */
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rc_del.rc_nh_old = wn_old[idx_old].nh;
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rc_del.rc_nh_weight = wn_old[idx_old].weight;
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cb(&rc_del, cbdata);
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idx_old++;
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} else {
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/*
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* nh_idx_old > nh_idx_new
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*
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* [1, ~3~, 4], [1, ~2~, 4]
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* [1, ~3~, 5], [1, ~2~, 4]
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* [1, ~3~, 4], [1, ~2~]
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*/
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if ((idx_new + 1 >= num_new) ||
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(wn_new[idx_new + 1].nh->nh_priv->nh_idx > nh_idx_old)) {
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/* No next item or next item is > current one */
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rc_add.rc_nh_new = wn_new[idx_new].nh;
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rc_add.rc_nh_weight = wn_new[idx_new].weight;
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cb(&rc_add, cbdata);
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idx_new++;
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}
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/* In any case, delete current old */
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rc_del.rc_nh_old = wn_old[idx_old].nh;
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rc_del.rc_nh_weight = wn_old[idx_old].weight;
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cb(&rc_del, cbdata);
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idx_old++;
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}
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}
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while (idx_old < num_old) {
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rc_del.rc_nh_old = wn_old[idx_old].nh;
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rc_del.rc_nh_weight = wn_old[idx_old].weight;
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cb(&rc_del, cbdata);
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idx_old++;
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}
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while (idx_new < num_new) {
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rc_add.rc_nh_new = wn_new[idx_new].nh;
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rc_add.rc_nh_weight = wn_new[idx_new].weight;
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cb(&rc_add, cbdata);
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idx_new++;
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}
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}
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/*
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* Decompose multipath cmd info @rc into a list of add/del/change
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* single-path operations, calling @cb callback for each operation.
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* Assumes at least one of the nexthops in @rc is multipath.
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*/
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void
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rib_decompose_notification(struct rib_cmd_info *rc, route_notification_t *cb,
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void *cbdata)
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{
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struct weightened_nhop *wn;
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uint32_t num_nhops;
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struct rib_cmd_info rc_new;
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rc_new = *rc;
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DPRINTF("cb=%p cmd=%d nh_old=%p nh_new=%p",
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cb, rc->cmd, rc->nh_old, rc->nh_new);
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switch (rc->rc_cmd) {
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case RTM_ADD:
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if (!NH_IS_NHGRP(rc->rc_nh_new))
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return;
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wn = nhgrp_get_nhops((struct nhgrp_object *)rc->rc_nh_new, &num_nhops);
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for (uint32_t i = 0; i < num_nhops; i++) {
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rc_new.rc_nh_new = wn[i].nh;
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rc_new.rc_nh_weight = wn[i].weight;
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cb(&rc_new, cbdata);
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}
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break;
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case RTM_DELETE:
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if (!NH_IS_NHGRP(rc->rc_nh_old))
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return;
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wn = nhgrp_get_nhops((struct nhgrp_object *)rc->rc_nh_old, &num_nhops);
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for (uint32_t i = 0; i < num_nhops; i++) {
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rc_new.rc_nh_old = wn[i].nh;
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rc_new.rc_nh_weight = wn[i].weight;
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cb(&rc_new, cbdata);
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}
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break;
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case RTM_CHANGE:
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if (!NH_IS_NHGRP(rc->rc_nh_old) && !NH_IS_NHGRP(rc->rc_nh_new))
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return;
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decompose_change_notification(rc, cb, cbdata);
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break;
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}
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}
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#endif
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