From 6f3f43d9304e2a9b9b62e1df32496c7609089fe1 Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Thu, 5 Feb 2015 05:43:57 -0600
Subject: [PATCH] IPv6:  Add a netmaks for the local link address

---
 include/nuttx/net/ip.h         | 9 +++++----
 net/devif/devif_initialize.c   | 9 +++++++--
 net/icmpv6/icmpv6_autoconfig.c | 6 +++++-
 3 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/include/nuttx/net/ip.h b/include/nuttx/net/ip.h
index 06aa7c9888..c46c7f00a0 100644
--- a/include/nuttx/net/ip.h
+++ b/include/nuttx/net/ip.h
@@ -220,16 +220,17 @@ extern "C"
 /* Well-known IP addresses */
 
 #ifdef CONFIG_NET_IPv4
-EXTERN const in_addr_t g_ipv4_alloneaddr;
-EXTERN const in_addr_t g_ipv4_allzeroaddr;
+EXTERN const in_addr_t g_ipv4_alloneaddr;       /* An address of all ones */
+EXTERN const in_addr_t g_ipv4_allzeroaddr;      /* An address of all zeroes */
 #endif
 
 #ifdef CONFIG_NET_IPv6
-EXTERN const net_ipv6addr_t g_ipv6_alloneaddr;
-EXTERN const net_ipv6addr_t g_ipv6_allzeroaddr;
+EXTERN const net_ipv6addr_t g_ipv6_alloneaddr;  /* An address of all ones */
+EXTERN const net_ipv6addr_t g_ipv6_allzeroaddr; /* An address of all zeroes */
 #ifdef CONFIG_NET_ICMPv6_AUTOCONF
 EXTERN const net_ipv6addr_t g_ipv6_allnodes;    /* All link local nodes */
 EXTERN const net_ipv6addr_t g_ipv6_allrouters;  /* All link local routers */
+EXTERN const net_ipv6addr_t g_ipv6_llnetmask;   /* Netmask for local link address */
 #endif
 #endif
 
diff --git a/net/devif/devif_initialize.c b/net/devif/devif_initialize.c
index 1f32e67f3a..ee332b2cfa 100644
--- a/net/devif/devif_initialize.c
+++ b/net/devif/devif_initialize.c
@@ -85,12 +85,12 @@ uint8_t g_reassembly_timer;
 
 #ifdef CONFIG_NET_IPv6
 
-const net_ipv6addr_t g_ipv6_alloneaddr =
+const net_ipv6addr_t g_ipv6_alloneaddr =  /* An address of all ones */
 {
   0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff, 0xffff
 };
 
-const net_ipv6addr_t g_ipv6_allzeroaddr =
+const net_ipv6addr_t g_ipv6_allzeroaddr = /* An address of all zeroes */
 {
   0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000, 0x0000
 };
@@ -112,6 +112,11 @@ const net_ipv6addr_t g_ipv6_allrouters =  /* All link local routers */
   HTONS(0x0002)
 };
 
+const net_ipv6addr_t g_ipv6_llnetmask =   /* Netmask for local link address */
+{
+  0xffff, 0xffff, 0xffff, 0xffff, 0x0000, 0x0000, 0x0000, 0x0000
+};
+
 #ifdef CONFIG_NET_ETHERNET
 
 /* IPv6 Multi-cast Ethernet addresses.  Formed from the 16-bit prefix:
diff --git a/net/icmpv6/icmpv6_autoconfig.c b/net/icmpv6/icmpv6_autoconfig.c
index 06d795bbe0..4854c094bb 100644
--- a/net/icmpv6/icmpv6_autoconfig.c
+++ b/net/icmpv6/icmpv6_autoconfig.c
@@ -515,8 +515,12 @@ int icmpv6_autoconfig(FAR struct net_driver_s *dev)
           netdev_ifdown(dev);
         }
 
+      /* Set a netmask for the local link address */
+
+      net_ipv6addr_copy(dev->d_ipv6netmask, g_ipv6_llnetmask);
+
       /* Leave the network up and return success (even though things did not
-       * work out quite the way we wanted.
+       * work out quite the way we wanted).
        */
 
       net_unlock(save);