From 8718ac0c4bf17372e7daff6b93c57cca1001c12a Mon Sep 17 00:00:00 2001
From: Matthew <m@metaquanta.com>
Date: Tue, 30 Jun 2020 02:22:08 -0400
Subject: [PATCH 1/3] duckdns doesn't permit subdomains or underscores

---
 dnsapi/dns_duckdns.sh | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/dnsapi/dns_duckdns.sh b/dnsapi/dns_duckdns.sh
index 711b81ee..aa7911d3 100755
--- a/dnsapi/dns_duckdns.sh
+++ b/dnsapi/dns_duckdns.sh
@@ -91,13 +91,13 @@ dns_duckdns_rm() {
 
 ####################  Private functions below ##################################
 
-#fulldomain=_acme-challenge.domain.duckdns.org
+#fulldomain=acme-challenge-domain.duckdns.org
 #returns
-# _duckdns_domain=domain
+# _duckdns_domain=acme-challenge-domain
 _duckdns_get_domain() {
 
   # We'll extract the domain/username from full domain
-  _duckdns_domain="$(printf "%s" "$fulldomain" | _lower_case | _egrep_o '[.][^.][^.]*[.]duckdns.org' | cut -d . -f 2)"
+  _duckdns_domain="$(printf "%s" "$fulldomain" | _lower_case | sed  's/^\([a-z0-9-]*\)\.duckdns\.org/\1/')"
 
   if [ -z "$_duckdns_domain" ]; then
     _err "Error extracting the domain."

From 4539d236df65f8cc0592cfbe1f044141c251f270 Mon Sep 17 00:00:00 2001
From: Matthew <m@metaquanta.com>
Date: Tue, 30 Jun 2020 07:19:41 -0400
Subject: [PATCH 2/3] dns_duckdns.sh - correctly extract domain

$fulldomain could be just 'domain.duckdns.org' if provided with --domain-alias or '_acme-challenge.domain.duckdns.org' otherwise. In the latter case, '_acme-challenge' is thrown away. Correctly extract 'domain' in both cases.
---
 dnsapi/dns_duckdns.sh | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/dnsapi/dns_duckdns.sh b/dnsapi/dns_duckdns.sh
index aa7911d3..edfc48b0 100755
--- a/dnsapi/dns_duckdns.sh
+++ b/dnsapi/dns_duckdns.sh
@@ -91,13 +91,12 @@ dns_duckdns_rm() {
 
 ####################  Private functions below ##################################
 
-#fulldomain=acme-challenge-domain.duckdns.org
-#returns
-# _duckdns_domain=acme-challenge-domain
+# fulldomain may be 'domain.duckdns.org' (if using --domain-alias) or '_acme-challenge.domain.duckdns.org'
+# either way, return 'domain'. (duckdns does not allow further subdomains and restricts domains to [a-z0-9-].)
 _duckdns_get_domain() {
 
   # We'll extract the domain/username from full domain
-  _duckdns_domain="$(printf "%s" "$fulldomain" | _lower_case | sed  's/^\([a-z0-9-]*\)\.duckdns\.org/\1/')"
+  _duckdns_domain="$(printf "%s" "$fulldomain" | _lower_case | _egrep_o '^(_acme-challenge\.)?[a-z0-9-]*\.duckdns\.org' | sed -E 's/^(_acme-challenge\.)?([a-z0-9-]*)\.duckdns\.org/\2/')"
 
   if [ -z "$_duckdns_domain" ]; then
     _err "Error extracting the domain."

From 21718a69d39106b689faae151dbf7aeb259b5597 Mon Sep 17 00:00:00 2001
From: Matthew <m@metaquanta.com>
Date: Fri, 3 Jul 2020 07:48:38 -0400
Subject: [PATCH 3/3] Update dns_duckdns.sh

Don't depend on eregex in sed
---
 dnsapi/dns_duckdns.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dnsapi/dns_duckdns.sh b/dnsapi/dns_duckdns.sh
index edfc48b0..11b685c0 100755
--- a/dnsapi/dns_duckdns.sh
+++ b/dnsapi/dns_duckdns.sh
@@ -96,7 +96,7 @@ dns_duckdns_rm() {
 _duckdns_get_domain() {
 
   # We'll extract the domain/username from full domain
-  _duckdns_domain="$(printf "%s" "$fulldomain" | _lower_case | _egrep_o '^(_acme-challenge\.)?[a-z0-9-]*\.duckdns\.org' | sed -E 's/^(_acme-challenge\.)?([a-z0-9-]*)\.duckdns\.org/\2/')"
+  _duckdns_domain="$(printf "%s" "$fulldomain" | _lower_case | _egrep_o '^(_acme-challenge\.)?[a-z0-9-]*\.duckdns\.org' | sed 's/^\(_acme-challenge\.\)\?\([a-z0-9-]*\)\.duckdns\.org/\2/')"
 
   if [ -z "$_duckdns_domain" ]; then
     _err "Error extracting the domain."