Add reverse DNS (ip to name) resolution

Change-Id: Ic531d820b1846ff7363e5c396ac0b1176e87b401
Signed-off-by: Dave Barach <dave@barachs.net>
diff --git a/src/vnet/dns/dns.api b/src/vnet/dns/dns.api
index 5557445..f188b05 100644
--- a/src/vnet/dns/dns.api
+++ b/src/vnet/dns/dns.api
@@ -52,9 +52,19 @@
 define dns_resolve_name {
     u32 client_index;
     u32 context;
-    u8 name[128];
+    u8 name[256];
  };
 
+/** \brief DNS name resolution reply
+
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+    @param retval - return value, 0 => success
+    @param ip4_set - indicates that the ip4 address is valid
+    @param ip6_set - indicates that the ip6 address is valid
+    @param ip4_address - the ip4 name resolution reply
+    @param ip6_address - the ip6 name resolution reply
+*/
 define dns_resolve_name_reply {
     u32 context;
     i32 retval;
@@ -64,3 +74,30 @@
     u8 ip6_address[16];
 };
 
+/** \brief DNS IP -> name resolution request
+
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+    @param is_ip6 - set if the reverse-DNS request is an ip6 address
+    @param address - the address to map to a name
+*/
+define dns_resolve_ip {
+    u32 client_index;
+    u32 context;
+    u8 is_ip6;
+    u8 address[16];
+ };
+
+/** \brief DNS ip->name resolution reply
+
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+    @param retval - return value, 0 => success
+    @param name - canonical name for the indicated IP address
+*/
+define dns_resolve_ip_reply {
+    u32 context;
+    i32 retval;
+    u8 name[256];
+};
+