From c8702916e90e709172ad034f754a5bbeec1c0e88 Mon Sep 17 00:00:00 2001 From: glebius Date: Wed, 24 Oct 2012 09:53:34 +0000 Subject: [PATCH] Merge 240073 from head: Provide a sysctl switch that allows to install ARP entries with multicast bit set. FreeBSD refuses to install such entries since 9.0, and this broke installations running Microsoft NLB, which are violating standards. Tested by: Tarasov Oleg git-svn-id: svn://svn.freebsd.org/base/stable/9@241992 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f --- sys/netinet/if_ether.c | 8 +++++--- usr.sbin/arp/arp.4 | 11 +++++++++++ 2 files changed, 16 insertions(+), 3 deletions(-) diff --git a/sys/netinet/if_ether.c b/sys/netinet/if_ether.c index 62634ed4a..3042e4d39 100644 --- a/sys/netinet/if_ether.c +++ b/sys/netinet/if_ether.c @@ -481,6 +481,7 @@ arpintr(struct mbuf *m) static int log_arp_wrong_iface = 1; static int log_arp_movements = 1; static int log_arp_permanent_modify = 1; +static int allow_multicast = 0; SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_wrong_iface, CTLFLAG_RW, &log_arp_wrong_iface, 0, @@ -491,7 +492,8 @@ SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_movements, CTLFLAG_RW, SYSCTL_INT(_net_link_ether_inet, OID_AUTO, log_arp_permanent_modify, CTLFLAG_RW, &log_arp_permanent_modify, 0, "log arp replies from MACs different than the one in the permanent arp entry"); - +SYSCTL_INT(_net_link_ether_inet, OID_AUTO, allow_multicast, CTLFLAG_RW, + &allow_multicast, 0, "accept multicast addresses"); static void in_arpinput(struct mbuf *m) @@ -536,8 +538,8 @@ in_arpinput(struct mbuf *m) return; } - if (ETHER_IS_MULTICAST(ar_sha(ah))) { - log(LOG_NOTICE, "in_arp: %*D is multicast\n", + if (allow_multicast == 0 && ETHER_IS_MULTICAST(ar_sha(ah))) { + log(LOG_NOTICE, "arp: %*D is multicast\n", ifp->if_addrlen, (u_char *)ar_sha(ah), ":"); return; } diff --git a/usr.sbin/arp/arp.4 b/usr.sbin/arp/arp.4 index 5d4685040..eaad84ef0 100644 --- a/usr.sbin/arp/arp.4 +++ b/usr.sbin/arp/arp.4 @@ -120,6 +120,12 @@ of the .Xr sysctl 3 MIB. .Bl -tag -width "log_arp_permanent_modify" +.It Va allow_multicast +Should the kernel install ARP entries with multicast bit set in +the hardware address. +Installing such entries is RFC 1812 violation, but some prorietary +load balancing techniques require routers on network to do so. +Turned off by default. .It Va log_arp_movements Should the kernel log movements of IP addresses from one hardware address to an other. @@ -203,6 +209,11 @@ entry in the local ARP table. This error will only be logged if the sysctl .Va net.link.ether.inet.log_arp_permanent_modify is set to 1, which is the system's default behaviour. +.It "arp: %x:%x:%x:%x:%x:%x is multicast" +Kernel refused to install an entry with multicast hardware address. +If you really want such addresses being installed, set the sysctl +.Va net.link.ether.inet.allow_multicast +to a positive value. .El .Sh SEE ALSO .Xr inet 4 , -- 2.45.0