* Fixes a bug causing the same DNS ECS option table to be useable only once

because of a side effect on the address family member.

* Allows the ECS address family to be supplied either as string or integer.

nselib/dns.lua

@@ -307,7 +307,7 @@ end
 -- * <code>id</code>: numeric value to use for the DNS transaction id
 -- * <code>nsid</code>: If true, queries the server for the nameserver identifier (RFC 5001)
 -- * <code>subnet</code>: table, if set perform a edns-client-subnet lookup. The table should contain the fields:
---                        <code>family</code> - string can be either inet or inet6
+--                        <code>family</code> - IPv4: "inet" or 1 (default), IPv6: "inet6" or 2
 --                        <code>address</code> - string containing the originating subnet IP address
 --                        <code>mask</code> - number containing the number of subnet bits
 -- @return <code>true</code> if a dns response was received and contained an answer of the requested type,
@@ -360,9 +360,6 @@ function query(dname, options)
   if ( options.nsid ) then
     addNSID(pkt, dnssec)
   elseif ( options.subnet ) then
-    local family = { ["inet"] = 1, ["inet6"] = 2 }
-    assert( family[options.subnet.family], "Unsupported subnet family")
-    options.subnet.family = family[options.subnet.family]
     addClientSubnet(pkt, dnssec, options.subnet )
   elseif ( dnssec.DO ) then
     addOPT(pkt, {DO = true})
@@ -1402,13 +1399,18 @@ end
 -- @param pkt Table representing DNS packet.
 -- @param Z Table of Z flags. Only DO is supported.
 -- @param client_subnet table containing the following fields
---        <code>family</code>  - 1 IPv4, 2 - IPv6
+--        <code>family</code>  - IPv4: "inet" or 1 (default), IPv6: "inet6" or 2
 --        <code>mask</code>    - byte containing the length of the subnet mask
 --        <code>address</code> - string containing the IP address
 function addClientSubnet(pkt,Z,subnet)
+  local family = subnet.family or 1
+  if type(family) == "string" then
+    family = ({inet=1,inet6=2})[family]
+  end
+  assert(family == 1 or family == 2, "Unsupported subnet family")
   local code = 8 -- https://www.iana.org/assignments/dns-parameters/dns-parameters.xhtml#dns-parameters-11
   local scope_mask = 0 -- In requests, it MUST be set to 0 see draft
-  local data = bin.pack(">SCCA",subnet.family or 1,subnet.mask,scope_mask,ipOps.ip_to_str(subnet.address))
+  local data = bin.pack(">SCCA",family,subnet.mask,scope_mask,ipOps.ip_to_str(subnet.address))
   local opt = bin.pack(">SS",code, #data) .. data
   addOPT(pkt,Z,opt)
 end