net.dns: Add resolver:tohostname() and dns.tohostname()

diff --git a/net/dns.lua b/net/dns.lua
index c0875b5a589240e13c4ba554627b0d51d597815b..f3d802919b9ae7dbeee77c8f6e7867395c117092 100644 (file)
--- a/net/dns.lua
+++ b/net/dns.lua
@@ -939,6 +939,9 @@ function resolver:lookupex(handler, qname, qtype, qclass)    -- - - - - - - - -
        return self:peek(qname, qtype, qclass) or self:query(qname, qtype, qclass);
 end
 
+function resolver:tohostname(ip)
+       return dns.lookup(ip:gsub("(%d+)%.(%d+)%.(%d+)%.(%d+)", "%4.%3.%2.%1.in-addr.arpa."), "PTR");
+end
 
 --print ---------------------------------------------------------------- print
 
@@ -1014,6 +1017,10 @@ function dns.lookup(...)    -- - - - - - - - - - - - - - - - - - - - -  lookup
        return _resolver:lookup(...);
 end
 
+function dns.tohostname(...)
+       return _resolver:tohostname(...);
+end
+
 function dns.purge(...)    -- - - - - - - - - - - - - - - - - - - - - -  purge
        return _resolver:purge(...);
 end