[PATCH] wg-quick: Linux and FreeBSD: Add support to search domain in wg-quick

[Ricardo Fraile]

Hello,


This patch allows wg-quick to pass the search domain to resolvconf with 
the option 'DNSSearch=' as it already does with the 'DNS=' option. As an 
example:

[Interface]
...
DNSSearch = lan1.example.com, lan2.example.com
...

This was discussed previously a few times:

https://lists.zx2c4.com/pipermail/wireguard/2019-January/003811.html
https://lists.zx2c4.com/pipermail/wireguard/2018-May/002882.html
https://lists.zx2c4.com/pipermail/wireguard/2019-September/004578.html


Thanks,
Ricardo F.




diff --git a/src/man/wg-quick.8 b/src/man/wg-quick.8
index 6250adc..2094c30 100644
--- a/src/man/wg-quick.8
+++ b/src/man/wg-quick.8
@@ -1,4 +1,4 @@
-.TH WG-QUICK 8 "2016 January 1" ZX2C4 "WireGuard"
+.TH WG-QUICK 8 "2020 January 1" ZX2C4 "WireGuard"

  .SH NAME
  wg-quick - set up a WireGuard interface simply
@@ -82,6 +82,10 @@ DNS servers. May be specified multiple times. Upon 
bringing the interface up, th
  .BR resolvconf (8)
  are undesirable, the PostUp and PostDown keys below may be used 
instead.
  .IP \(bu
+DNSSearch \(em a comma-separated list of domain names to be set as the 
interface's
+search for hostname lookups. This options runs in conjunction with DNS 
and only if that is
+already set. Only available on Linux and FreeBSD.
+.IP \(bu
  MTU \(em if not specified, the MTU is automatically determined from the 
endpoint addresses
  or the system default route, which is usually a sane choice. However, 
to manually specify
  an MTU to override this automatic discovery, this value may be 
specified explicitly.
@@ -124,6 +128,8 @@ traffic:
  .br
      \fBDNS = 10.200.100.1\fP
  .br
+    \fBDNSSearch = loc1.example.com, loc2.example.com\fP
+.br
      PrivateKey = oK56DE9Ue9zK76rAc8pBl6opph+1v36lm7cXXsQKrQM=
  .br

@@ -141,7 +147,7 @@ traffic:

  The `Address` field is added here in order to set up the address for 
the interface. The `DNS` field
  indicates that a DNS server for the interface should be configured via
-.BR resolvconf (8).
+.BR resolvconf (8), the `DNSSerach` field set the search domains with 
it too.
  The peer's allowed IPs entry implies that this interface should be 
configured as the default gateway,
  which this script does.

diff --git a/src/wg-quick/freebsd.bash b/src/wg-quick/freebsd.bash
index c390dcc..a108323 100755
--- a/src/wg-quick/freebsd.bash
+++ b/src/wg-quick/freebsd.bash
@@ -16,6 +16,7 @@ INTERFACE=""
  ADDRESSES=( )
  MTU=""
  DNS=( )
+DNS_SEARCH=( )
  TABLE=""
  PRE_UP=( )
  POST_UP=( )
@@ -85,6 +86,7 @@ parse_options() {
  			Address) ADDRESSES+=( ${value//,/ } ); continue ;;
  			MTU) MTU="$value"; continue ;;
  			DNS) DNS+=( ${value//,/ } ); continue ;;
+			DNSSearch) DNS_SEARCH+=( ${value//,/ } ); continue ;;
  			Table) TABLE="$value"; continue ;;
  			PreUp) PRE_UP+=( "$value" ); continue ;;
  			PreDown) PRE_DOWN+=( "$value" ); continue ;;
@@ -297,7 +299,11 @@ monitor_daemon() {
  HAVE_SET_DNS=0
  set_dns() {
  	[[ ${#DNS[@]} -gt 0 ]] || return 0
-	printf 'nameserver %s\n' "${DNS[@]}" | cmd resolvconf -a "$INTERFACE" 
-x
+	if [[ -n $DNS_SEARCH ]]; then
+		(printf 'nameserver %s\n' "${DNS[@]}" && printf 'search %s\n' 
"$DNS_SEARCH") | cmd resolvconf -a "$INTERFACE" -x
+	else
+		printf 'nameserver %s\n' "${DNS[@]}" | cmd resolvconf -a "$INTERFACE" 
-x
+	fi
  	HAVE_SET_DNS=1
  }

@@ -342,8 +348,9 @@ save_config() {
  	{ read -r _; while read -r _ _ _ address _; do
  		new_config+="Address = $address"$'\n'
  	done } < <(netstat -I "$INTERFACE" -n -W -f inet6)
-	while read -r address; do
-		[[ $address =~ ^nameserver\ ([a-zA-Z0-9_=+:%.-]+)$ ]] && 
new_config+="DNS = ${BASH_REMATCH[1]}"$'\n'
+	while read -r line; do
+		[[ $line =~ ^nameserver\ ([a-zA-Z0-9_=+:%.-]+)$ ]] && 
new_config+="DNS = ${BASH_REMATCH[1]}"$'\n'
+		[[ $line =~ ^search\ (.+)$ ]] && new_config+="DNSSearch = 
${BASH_REMATCH[1]/ /, }"$'\n'
  	done < <(resolvconf -l "$INTERFACE" 2>/dev/null)
  	[[ -n $MTU ]] && new_config+="MTU = $MTU"$'\n'
  	[[ -n $TABLE ]] && new_config+="Table = $TABLE"$'\n'
@@ -395,6 +402,7 @@ cmd_usage() {
  	  - Address: may be specified one or more times and contains one or 
more
  	    IP addresses (with an optional CIDR mask) to be set for the 
interface.
  	  - DNS: an optional DNS server to use while the device is up.
+	  - DNSSearch: Search list for host-name lookup to use while the 
device is up.
  	  - MTU: an optional MTU for the interface; if unspecified, 
auto-calculated.
  	  - Table: an optional routing table to which routes will be added; if
  	    unspecified or \`auto', the default table is used. If \`off', no 
routes
diff --git a/src/wg-quick/linux.bash b/src/wg-quick/linux.bash
index 7c2c002..1715354 100755
--- a/src/wg-quick/linux.bash
+++ b/src/wg-quick/linux.bash
@@ -16,6 +16,7 @@ INTERFACE=""
  ADDRESSES=( )
  MTU=""
  DNS=( )
+DNS_SEARCH=( )
  TABLE=""
  PRE_UP=( )
  POST_UP=( )
@@ -57,6 +58,7 @@ parse_options() {
  			Address) ADDRESSES+=( ${value//,/ } ); continue ;;
  			MTU) MTU="$value"; continue ;;
  			DNS) DNS+=( ${value//,/ } ); continue ;;
+			DNSSearch) DNS_SEARCH=${value//,/}; continue ;;
  			Table) TABLE="$value"; continue ;;
  			PreUp) PRE_UP+=( "$value" ); continue ;;
  			PreDown) PRE_DOWN+=( "$value" ); continue ;;
@@ -150,7 +152,11 @@ resolvconf_iface_prefix() {
  HAVE_SET_DNS=0
  set_dns() {
  	[[ ${#DNS[@]} -gt 0 ]] || return 0
-	printf 'nameserver %s\n' "${DNS[@]}" | cmd resolvconf -a 
"$(resolvconf_iface_prefix)$INTERFACE" -m 0 -x
+	if [[ -n $DNS_SEARCH ]]; then
+		(printf 'nameserver %s\n' "${DNS[@]}" && printf 'search %s\n' 
"$DNS_SEARCH") | cmd resolvconf -a 
"$(resolvconf_iface_prefix)$INTERFACE" -m 0 -x
+	else
+		printf 'nameserver %s\n' "${DNS[@]}" | cmd resolvconf -a 
"$(resolvconf_iface_prefix)$INTERFACE" -m 0 -x
+	fi
  	HAVE_SET_DNS=1
  }

@@ -253,8 +259,9 @@ save_config() {
  	for address in ${BASH_REMATCH[1]}; do
  		new_config+="Address = $address"$'\n'
  	done
-	while read -r address; do
-		[[ $address =~ ^nameserver\ ([a-zA-Z0-9_=+:%.-]+)$ ]] && 
new_config+="DNS = ${BASH_REMATCH[1]}"$'\n'
+	while read -r line; do
+		[[ $line =~ ^nameserver\ ([a-zA-Z0-9_=+:%.-]+)$ ]] && 
new_config+="DNS = ${BASH_REMATCH[1]}"$'\n'
+		[[ $line =~ ^search\ (.+)$ ]] && new_config+="DNSSearch = 
${BASH_REMATCH[1]/ /, }"$'\n'
  	done < <(resolvconf -l "$(resolvconf_iface_prefix)$INTERFACE" 
2>/dev/null || cat 
"/etc/resolvconf/run/interface/$(resolvconf_iface_prefix)$INTERFACE" 
2>/dev/null)
  	[[ -n $MTU && $(ip link show dev "$INTERFACE") =~ mtu\ ([0-9]+) ]] && 
new_config+="MTU = ${BASH_REMATCH[1]}"$'\n'
  	[[ -n $TABLE ]] && new_config+="Table = $TABLE"$'\n'
@@ -304,6 +311,7 @@ cmd_usage() {
  	  - Address: may be specified one or more times and contains one or 
more
  	    IP addresses (with an optional CIDR mask) to be set for the 
interface.
  	  - DNS: an optional DNS server to use while the device is up.
+	  - DNSSearch: Search list for host-name lookup to use while the 
device is up.
  	  - MTU: an optional MTU for the interface; if unspecified, 
auto-calculated.
  	  - Table: an optional routing table to which routes will be added; if
  	    unspecified or \`auto', the default table is used. If \`off', no 
routes