---

yaml
---
r: 170464
b: refs/heads/master
c: f7734fd
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 51953d5bc43e468f24cc573a45cde1d32af129b8
+refs/heads/master: f7734fdf61ec6bb848e0bafc1fb8bad2c124bb50

trunk/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.

trunk/include/linux/ipv6.h

@@ -167,6 +167,7 @@ struct ipv6_devconf {
 #endif
 	__s32		disable_ipv6;
 	__s32		accept_dad;
+	__s32		force_tllao;
 	void		*sysctl;
 };
 

trunk/net/ipv6/addrconf.c

@@ -4352,6 +4352,14 @@ static struct addrconf_sysctl_table
 			.mode		=	0644,
 			.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 */
 		}

trunk/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);