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-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 fbe427a..a0e134d 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 c662efa..ae74ede 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 1fd0a3d..bdcee69 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 f74e4e2..3507cfe 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);
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