dnsapi: Add option to set zone for nsupdate

Some DNS servers for which dns_nsupdate.sh is applicable (such
as dyn.com's 'Standard DNS' TSIG update mechanism), require that
the zone be set during the nsupdate transaction.  Therefore we
add a new environment variable NSUPDATE_ZONE which is used to
set the zone for the DNS TSIG transaction.

Signed-off-by: Daniel F. Dickinson <cshored@thecshore.com>

dnsapi/README.md

@@ -146,13 +146,17 @@ Finally, make the DNS server and update Key available to `acme.sh`
 export NSUPDATE_SERVER="dns.example.com"
 export NSUPDATE_KEY="/path/to/your/nsupdate.key"
 ```
+and optionally (depending on DNS server)
+```
+export NSUPDATE_ZONE="example.com"
+```
 
 Ok, let's issue a cert now:
 ```
 acme.sh --issue --dns dns_nsupdate -d example.com -d www.example.com
 ```
 
-The `NSUPDATE_SERVER` and `NSUPDATE_KEY` settings will be saved in `~/.acme.sh/account.conf` and will be reused when needed.
+The `NSUPDATE_SERVER`, `NSUPDATE_KEY`, and `NSUPDATE_ZONE` settings will be saved in `~/.acme.sh/account.conf` and will be reused when needed.
 
 
 ## 8. Use LuaDNS domain API

dnsapi/dns_nsupdate.sh

@@ -13,14 +13,24 @@ dns_nsupdate_add() {
   _saveaccountconf NSUPDATE_SERVER "${NSUPDATE_SERVER}"
   _saveaccountconf NSUPDATE_SERVER_PORT "${NSUPDATE_SERVER_PORT}"
   _saveaccountconf NSUPDATE_KEY "${NSUPDATE_KEY}"
+  _saveaccountconf NSUPDATE_ZONE "${NSUPDATE_ZONE}"
   _info "adding ${fulldomain}. 60 in txt \"${txtvalue}\""
   [ -n "$DEBUG" ] && [ "$DEBUG" -ge "$DEBUG_LEVEL_1" ] && nsdebug="-d"
   [ -n "$DEBUG" ] && [ "$DEBUG" -ge "$DEBUG_LEVEL_2" ] && nsdebug="-D"
-  nsupdate -k "${NSUPDATE_KEY}" $nsdebug <<EOF
+  if [ -z "${NSUPDATE_ZONE}" ]; then
+    nsupdate -k "${NSUPDATE_KEY}" $nsdebug <<EOF
 server ${NSUPDATE_SERVER}  ${NSUPDATE_SERVER_PORT} 
 update add ${fulldomain}. 60 in txt "${txtvalue}"
 send
 EOF
+  else
+    nsupdate -k "${NSUPDATE_KEY}" $nsdebug <<EOF
+server ${NSUPDATE_SERVER}  ${NSUPDATE_SERVER_PORT}
+zone ${NSUPDATE_ZONE}.
+update add ${fulldomain}. 60 in txt "${txtvalue}"
+send
+EOF
+  fi
   if [ $? -ne 0 ]; then
     _err "error updating domain"
     return 1
@@ -38,11 +48,20 @@ dns_nsupdate_rm() {
   _info "removing ${fulldomain}. txt"
   [ -n "$DEBUG" ] && [ "$DEBUG" -ge "$DEBUG_LEVEL_1" ] && nsdebug="-d"
   [ -n "$DEBUG" ] && [ "$DEBUG" -ge "$DEBUG_LEVEL_2" ] && nsdebug="-D"
-  nsupdate -k "${NSUPDATE_KEY}" $nsdebug <<EOF
+  if [ -z "${NSUPDATE_ZONE}" ]; then
+    nsupdate -k "${NSUPDATE_KEY}" $nsdebug <<EOF
 server ${NSUPDATE_SERVER}  ${NSUPDATE_SERVER_PORT} 
 update delete ${fulldomain}. txt
 send
 EOF
+  else
+    nsupdate -k "${NSUPDATE_KEY}" $nsdebug <<EOF
+server ${NSUPDATE_SERVER}  ${NSUPDATE_SERVER_PORT}
+zone ${NSUPDATE_ZONE}.
+update delete ${fulldomain}. txt
+send
+EOF
+  fi
   if [ $? -ne 0 ]; then
     _err "error updating domain"
     return 1