svn commit: r312439 - stable/11/sys/netinet
Gleb Smirnoff
glebius at FreeBSD.org
Thu Jan 19 23:57:03 UTC 2017
Josh,
did you notice my reply to the original commit?!
On Thu, Jan 19, 2017 at 11:38:31PM +0000, Josh Paetzel wrote:
J> Author: jpaetzel
J> Date: Thu Jan 19 23:38:31 2017
J> New Revision: 312439
J> URL: https://svnweb.freebsd.org/changeset/base/312439
J>
J> Log:
J> MFC 310847 310864
J>
J> Harden CARP against network loops.
J>
J> If there is a loop in the network a CARP that is in MASTER state will see it's
J> own broadcasts, which will then cause it to assume BACKUP state. When it
J> assumes BACKUP it will stop sending advertisements. In that state it will no
J> longer see advertisements and will assume MASTER...
J>
J> We can't catch all the cases where we are seeing our own CARP broadcast, but
J> we can catch the obvious case.
J>
J> Unbreak ip_carp with WITHOUT_INET6 enabled by conditionalizing all IPv6
J> structs under the INET6 #ifdef. Similarly (even though it doesn't seem
J> to affect the build), conditionalize all IPv4 structs under the INET
J> #ifdef
J>
J> This also unbreaks the LINT-NOINET6 tinderbox target on amd64; I have not
J> verified other MACHINE/TARGET pairs (e.g. armv6/arm).
J>
J> Submitted by: torek
J> Obtained from: FreeNAS
J> Pointyhat fix: ngie
J>
J> Modified:
J> stable/11/sys/netinet/ip_carp.c
J> Directory Properties:
J> stable/11/ (props changed)
J>
J> Modified: stable/11/sys/netinet/ip_carp.c
J> ==============================================================================
J> --- stable/11/sys/netinet/ip_carp.c Thu Jan 19 22:07:21 2017 (r312438)
J> +++ stable/11/sys/netinet/ip_carp.c Thu Jan 19 23:38:31 2017 (r312439)
J> @@ -581,27 +581,96 @@ carp6_input(struct mbuf **mp, int *offp,
J> }
J> #endif /* INET6 */
J>
J> +/*
J> + * This routine should not be necessary at all, but some switches
J> + * (VMWare ESX vswitches) can echo our own packets back at us,
J> + * and we must ignore them or they will cause us to drop out of
J> + * MASTER mode.
J> + *
J> + * We cannot catch all cases of network loops. Instead, what we
J> + * do here is catch any packet that arrives with a carp header
J> + * with a VHID of 0, that comes from an address that is our own.
J> + * These packets are by definition "from us" (even if they are from
J> + * a misconfigured host that is pretending to be us).
J> + *
J> + * The VHID test is outside this mini-function.
J> + */
J> +static int
J> +carp_source_is_self(struct mbuf *m, struct ifaddr *ifa, sa_family_t af)
J> +{
J> +#ifdef INET
J> + struct ip *ip4;
J> + struct in_addr in4;
J> +#endif
J> +#ifdef INET6
J> + struct ip6_hdr *ip6;
J> + struct in6_addr in6;
J> +#endif
J> +
J> + switch (af) {
J> +#ifdef INET
J> + case AF_INET:
J> + ip4 = mtod(m, struct ip *);
J> + in4 = ifatoia(ifa)->ia_addr.sin_addr;
J> + return (in4.s_addr == ip4->ip_src.s_addr);
J> +#endif
J> +#ifdef INET6
J> + case AF_INET6:
J> + ip6 = mtod(m, struct ip6_hdr *);
J> + in6 = ifatoia6(ifa)->ia_addr.sin6_addr;
J> + return (memcmp(&in6, &ip6->ip6_src, sizeof(in6)) == 0);
J> +#endif
J> + default:
J> + break;
J> + }
J> + return (0);
J> +}
J> +
J> static void
J> carp_input_c(struct mbuf *m, struct carp_header *ch, sa_family_t af)
J> {
J> struct ifnet *ifp = m->m_pkthdr.rcvif;
J> - struct ifaddr *ifa;
J> + struct ifaddr *ifa, *match;
J> struct carp_softc *sc;
J> uint64_t tmp_counter;
J> struct timeval sc_tv, ch_tv;
J> + int error;
J>
J> - /* verify that the VHID is valid on the receiving interface */
J> + /*
J> + * Verify that the VHID is valid on the receiving interface.
J> + *
J> + * There should be just one match. If there are none
J> + * the VHID is not valid and we drop the packet. If
J> + * there are multiple VHID matches, take just the first
J> + * one, for compatibility with previous code. While we're
J> + * scanning, check for obvious loops in the network topology
J> + * (these should never happen, and as noted above, we may
J> + * miss real loops; this is just a double-check).
J> + */
J> IF_ADDR_RLOCK(ifp);
J> - IFNET_FOREACH_IFA(ifp, ifa)
J> - if (ifa->ifa_addr->sa_family == af &&
J> - ifa->ifa_carp->sc_vhid == ch->carp_vhid) {
J> - ifa_ref(ifa);
J> - break;
J> - }
J> + error = 0;
J> + match = NULL;
J> + IFNET_FOREACH_IFA(ifp, ifa) {
J> + if (match == NULL && ifa->ifa_carp != NULL &&
J> + ifa->ifa_addr->sa_family == af &&
J> + ifa->ifa_carp->sc_vhid == ch->carp_vhid)
J> + match = ifa;
J> + if (ch->carp_vhid == 0 && carp_source_is_self(m, ifa, af))
J> + error = ELOOP;
J> + }
J> + ifa = error ? NULL : match;
J> + if (ifa != NULL)
J> + ifa_ref(ifa);
J> IF_ADDR_RUNLOCK(ifp);
J>
J> if (ifa == NULL) {
J> - CARPSTATS_INC(carps_badvhid);
J> + if (error == ELOOP) {
J> + CARP_DEBUG("dropping looped packet on interface %s\n",
J> + ifp->if_xname);
J> + CARPSTATS_INC(carps_badif); /* ??? */
J> + } else {
J> + CARPSTATS_INC(carps_badvhid);
J> + }
J> m_freem(m);
J> return;
J> }
J> @@ -787,12 +856,41 @@ carp_send_ad_error(struct carp_softc *sc
J> }
J> }
J>
J> +/*
J> + * Pick the best ifaddr on the given ifp for sending CARP
J> + * advertisements.
J> + *
J> + * "Best" here is defined by ifa_preferred(). This function is much
J> + * much like ifaof_ifpforaddr() except that we just use ifa_preferred().
J> + *
J> + * (This could be simplified to return the actual address, except that
J> + * it has a different format in AF_INET and AF_INET6.)
J> + */
J> +static struct ifaddr *
J> +carp_best_ifa(int af, struct ifnet *ifp)
J> +{
J> + struct ifaddr *ifa, *best;
J> +
J> + if (af >= AF_MAX)
J> + return (NULL);
J> + best = NULL;
J> + IF_ADDR_RLOCK(ifp);
J> + TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
J> + if (ifa->ifa_addr->sa_family == af &&
J> + (best == NULL || ifa_preferred(best, ifa)))
J> + best = ifa;
J> + }
J> + IF_ADDR_RUNLOCK(ifp);
J> + if (best != NULL)
J> + ifa_ref(best);
J> + return (best);
J> +}
J> +
J> static void
J> carp_send_ad_locked(struct carp_softc *sc)
J> {
J> struct carp_header ch;
J> struct timeval tv;
J> - struct sockaddr sa;
J> struct ifaddr *ifa;
J> struct carp_header *ch_ptr;
J> struct mbuf *m;
J> @@ -841,9 +939,7 @@ carp_send_ad_locked(struct carp_softc *s
J> ip->ip_sum = 0;
J> ip_fillid(ip);
J>
J> - bzero(&sa, sizeof(sa));
J> - sa.sa_family = AF_INET;
J> - ifa = ifaof_ifpforaddr(&sa, sc->sc_carpdev);
J> + ifa = carp_best_ifa(AF_INET, sc->sc_carpdev);
J> if (ifa != NULL) {
J> ip->ip_src.s_addr =
J> ifatoia(ifa)->ia_addr.sin_addr.s_addr;
J> @@ -887,11 +983,9 @@ carp_send_ad_locked(struct carp_softc *s
J> ip6->ip6_vfc |= IPV6_VERSION;
J> ip6->ip6_hlim = CARP_DFLTTL;
J> ip6->ip6_nxt = IPPROTO_CARP;
J> - bzero(&sa, sizeof(sa));
J>
J> /* set the source address */
J> - sa.sa_family = AF_INET6;
J> - ifa = ifaof_ifpforaddr(&sa, sc->sc_carpdev);
J> + ifa = carp_best_ifa(AF_INET6, sc->sc_carpdev);
J> if (ifa != NULL) {
J> bcopy(IFA_IN6(ifa), &ip6->ip6_src,
J> sizeof(struct in6_addr));
J> _______________________________________________
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--
Totus tuus, Glebius.
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