From c7b0826da54841af55180d86393c2437fe26a12c Mon Sep 17 00:00:00 2001
From: Philippe Pittoli <karchnu@karchnu.fr>
Date: Mon, 18 Mar 2024 02:30:39 +0100
Subject: [PATCH] SRV: fixes a long standing neglect of SRV RRs.

---
 src/storage/zone.cr | 38 +++++++++++++++++++++++++++-----------
 1 file changed, 27 insertions(+), 11 deletions(-)

diff --git a/src/storage/zone.cr b/src/storage/zone.cr
index bcc7532..e7618ed 100644
--- a/src/storage/zone.cr
+++ b/src/storage/zone.cr
@@ -1,5 +1,22 @@
 require "ipaddress"
 
+# Domains cannot be parsed using regexes.
+# Yet, that will be good enough for now.
+def label_pattern
+	/(?:[0-9A-Za-z][0-9A-Za-z-]{0,62})/
+end
+
+def subdomain_pattern
+	/\b(?:[0-9A-Za-z][0-9A-Za-z-]{0,62})(?:\.(?:[0-9A-Za-z][0-9A-Za-z-]{0,62}))*\b/
+end
+
+# /^(((?!-))(xn--|_{1,1})?[a-z0-9-]{0,61}[a-z0-9]{1,1}\.)*
+#   ((xn--)?[a-z0-9][a-z0-9\-]{0,60}[a-z0-9]|(xn--)?[a-z0-9]{1,60})
+#   \.[a-z]{2,}\.?$/
+def hostname_pattern
+	/\b(?:[0-9A-Za-z][0-9A-Za-z-]{0,62})(?:\.(?:[0-9A-Za-z][0-9A-Za-z-]{0,62}))*(\.?|\b)/
+end
+
 # Store a DNS zone.
 #
 # Several common resource record types are accepted: SOA PTR A AAAA TXT CNAME NS MX SRV.
@@ -567,10 +584,8 @@ class DNSManager::Storage::Zone
 			end
 
 			# MX target can either be a subdomain or a FQDN.
-			unless Zone.is_subdomain_valid? @target
-				unless Zone.is_domain_valid? @target
-					errors << "MX invalid target (domain): #{@target}"
-				end
+			unless (Zone.is_subdomain_valid? @target || Zone.is_domain_valid? @target)
+				errors << "MX invalid target (domain or subdomain): #{@target}"
 			end
 
 			errors
@@ -589,15 +604,15 @@ class DNSManager::Storage::Zone
 		def get_errors : Array(Error)
 			errors = [] of Error
 
-			# SRV name should be created from scratch, client should send an empty name.
-			# WON'T FIX: name verification.
+			# SRV name represents the service name.
 
 			if @ttl < Zone.ttl_limit_min
 				errors << "SRV invalid ttl: #{@ttl}, shouldn't be less than #{Zone.ttl_limit_min}"
 			end
 
+			# SRV target can either be a subdomain or a FQDN.
 			unless Zone.is_domain_valid? @target
-				errors << "SRV invalid target (domain): #{@target}"
+				errors << "SRV invalid target domain: #{@target}"
 			end
 
 			errors
@@ -605,7 +620,7 @@ class DNSManager::Storage::Zone
 
 		def to_s(io : IO)
 			io << "(#{ "%4d" % @rrid }) "
-			io << "#{ "%30s" % @name} "
+			io << "_#{@name.downcase}._#{@protocol.downcase} "
 			io << "#{ "%6d" % @ttl} SRV "
 			io << "#{ "%3d" % @priority} "
 			io << "#{ "%3d" % @weight} "
@@ -614,7 +629,8 @@ class DNSManager::Storage::Zone
 		end
 
 		def to_bind9(io : IO)
-			io << "#{@name} #{@ttl} IN SRV #{@priority} #{@weight} #{@port} #{@target}\n"
+			io << "_#{@name.downcase}._#{@protocol.downcase} "
+			io << "#{@ttl} IN SRV #{@priority} #{@weight} #{@port} #{@target}\n"
 		end
 	end
 
@@ -703,7 +719,7 @@ class DNSManager::Storage::Zone
 
 	# This regex only is "good enough for now".
 	def self.is_domain_valid?(domain) : Bool
-		if domain =~ /^(((?!-))(xn--|_{1,1})?[a-z0-9-]{0,61}[a-z0-9]{1,1}\.)*((xn--)?[a-z0-9][a-z0-9\-]{0,60}[a-z0-9]|(xn--)?[a-z0-9]{1,60})\.[a-z]{2,}\.?$/
+		if domain =~ hostname_pattern
 			true
 		else
 			false
@@ -715,7 +731,7 @@ class DNSManager::Storage::Zone
 
 	# This regex only is "good enough for now".
 	def self.is_subdomain_valid?(subdomain) : Bool
-		if subdomain =~ /^(((?!-))(xn--|_{1,1})?[a-z0-9-]{0,61}[a-z0-9]{1,1}\.)*(xn--)?[a-z0-9][a-z0-9\-]{0,60}[a-z0-9]*[a-z]+|[a-z]+|[a-z][a-z0-9]+[a-z]+$/
+		if subdomain =~ subdomain_pattern
 			true
 		else
 			false