aboutsummaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorOctavian Purdila <opurdila@ixiacom.com>2009-10-02 11:39:15 +0000
committerDavid S. Miller <davem@davemloft.net>2009-10-07 01:10:45 -0700
commitf7734fdf61ec6bb848e0bafc1fb8bad2c124bb50 (patch)
treed2e5ab4c87f54982e3fd2898d37b2a5f8624c444
parent51953d5bc43e468f24cc573a45cde1d32af129b8 (diff)
make TLLAO option for NA packets configurable
On Friday 02 October 2009 20:53:51 you wrote: > This is good although I would have shortened the name. Ah, I knew I forgot something :) Here is v4. tavi >From 24d96d825b9fa832b22878cc6c990d5711968734 Mon Sep 17 00:00:00 2001 From: Octavian Purdila <opurdila@ixiacom.com> Date: Fri, 2 Oct 2009 00:51:15 +0300 Subject: [PATCH] ipv6: new sysctl for sending TLLAO with unicast NAs Neighbor advertisements responding to unicast neighbor solicitations did not include the target link-layer address option. This patch adds a new sysctl option (disabled by default) which controls whether this option should be sent even with unicast NAs. The need for this arose because certain routers expect the TLLAO in some situations even as a response to unicast NS packets. Moreover, RFC 2461 recommends sending this to avoid a race condition (section 4.4, Target link-layer address) Signed-off-by: Cosmin Ratiu <cratiu@ixiacom.com> Signed-off-by: Octavian Purdila <opurdila@ixiacom.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--Documentation/networking/ip-sysctl.txt18
-rw-r--r--include/linux/ipv6.h1
-rw-r--r--net/ipv6/addrconf.c8
-rw-r--r--net/ipv6/ndisc.c1
4 files changed, 28 insertions, 0 deletions
diff --git a/Documentation/networking/ip-sysctl.txt b/Documentation/networking/ip-sysctl.txt
index fbe427a6580c..a0e134dd2523 100644
--- a/Documentation/networking/ip-sysctl.txt
+++ b/Documentation/networking/ip-sysctl.txt
@@ -1086,6 +1086,24 @@ accept_dad - INTEGER
2: Enable DAD, and disable IPv6 operation if MAC-based duplicate
link-local address has been found.
+force_tllao - BOOLEAN
+ Enable sending the target link-layer address option even when
+ responding to a unicast neighbor solicitation.
+ Default: FALSE
+
+ Quoting from RFC 2461, section 4.4, Target link-layer address:
+
+ "The option MUST be included for multicast solicitations in order to
+ avoid infinite Neighbor Solicitation "recursion" when the peer node
+ does not have a cache entry to return a Neighbor Advertisements
+ message. When responding to unicast solicitations, the option can be
+ omitted since the sender of the solicitation has the correct link-
+ layer address; otherwise it would not have be able to send the unicast
+ solicitation in the first place. However, including the link-layer
+ address in this case adds little overhead and eliminates a potential
+ race condition where the sender deletes the cached link-layer address
+ prior to receiving a response to a previous solicitation."
+
icmp/*:
ratelimit - INTEGER
Limit the maximal rates for sending ICMPv6 packets.
diff --git a/include/linux/ipv6.h b/include/linux/ipv6.h
index c662efa68289..ae74ede1abe7 100644
--- a/include/linux/ipv6.h
+++ b/include/linux/ipv6.h
@@ -167,6 +167,7 @@ struct ipv6_devconf {
#endif
__s32 disable_ipv6;
__s32 accept_dad;
+ __s32 force_tllao;
void *sysctl;
};
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 1fd0a3d775d2..bdcee6981c60 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -4353,6 +4353,14 @@ static struct addrconf_sysctl_table
.proc_handler = proc_dointvec,
},
{
+ .ctl_name = CTL_UNNUMBERED,
+ .procname = "force_tllao",
+ .data = &ipv6_devconf.force_tllao,
+ .maxlen = sizeof(int),
+ .mode = 0644,
+ .proc_handler = proc_dointvec
+ },
+ {
.ctl_name = 0, /* sentinel */
}
},
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index f74e4e2cdd06..3507cfe1e7a2 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -598,6 +598,7 @@ static void ndisc_send_na(struct net_device *dev, struct neighbour *neigh,
icmp6h.icmp6_solicited = solicited;
icmp6h.icmp6_override = override;
+ inc_opt |= ifp->idev->cnf.force_tllao;
__ndisc_send(dev, neigh, daddr, src_addr,
&icmp6h, solicited_addr,
inc_opt ? ND_OPT_TARGET_LL_ADDR : 0);

Privacy Policy