From: Michael Tremer <michael.tremer@ipfire.org>
Date: Sat, 13 Oct 2012 18:39:27 +0000 (+0000)
Subject: dns: Adds a number of new functions.
X-Git-Tag: 006~19
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e5651e17d2a01e39a4e453a9a363496f00cf0f92;p=network.git

dns: Adds a number of new functions.

The configuration file layout is the same like for the
static routes.
DNS servers from DHCP are now taken into account and prioritized.
Duplicate entries are removed.
---

diff --git a/dhclient-script b/dhclient-script
index 789eee32..9325a21b 100644
--- a/dhclient-script
+++ b/dhclient-script
@@ -99,6 +99,7 @@ case "${reason}" in
 					routing_db_set ${interface} ipv4 active 1
 					routing_db_set ${interface} ipv4 domain-name "${new_domain_name}"
 					routing_db_set ${interface} ipv4 domain-name-servers "${new_domain_name_servers}"
+					routing_db_set ${interface} ipv4 domain-name-servers-priority "${DNS_SERVER_DYNAMIC_PRIORITY}"
 
 					# Update the routing tables.
 					routing_update ${interface} ipv4
diff --git a/functions.dns b/functions.dns
index 5f964ba5..66066376 100644
--- a/functions.dns
+++ b/functions.dns
@@ -36,6 +36,11 @@ NETWORK_CONFIG_FILE_PARAMS="${NETWORK_CONFIG_FILE_PARAMS} DNS_SEARCH_DOMAINS"
 DNS_ADVERTISE_SERVERS="true"
 
 DNS_SERVER_CONFIG_FILE="${NETWORK_CONFIG_DIR}/dns-servers"
+NETWORK_CONFIG_DNS_SERVER_PARAMS="server priority"
+
+# Set the default priority for DNS servers.
+DNS_SERVER_DEFAULT_PRIORITY="100"
+DNS_SERVER_DYNAMIC_PRIORITY="10"
 
 # Path to the configuration file of the DNS resolver.
 RESOLV_CONF="/etc/resolv.conf"
@@ -51,33 +56,56 @@ function dns_get_hostname() {
 	)
 }
 
-function __dns_server_println() {
-	local server=${1}
-	local priority=${2}
+function dns_server_list() {
+	[ -r "${DNS_SERVER_CONFIG_FILE}" ] || return ${EXIT_OK}
 
-	print "%-20s %s" "${server}" "${priority}"
-}
+	local line
+	local ${NETWORK_CONFIG_DNS_SERVER_PARAMS}
+
+	local format="%-20s %-8s"
+	print "${format}" "SERVER" "PRIORITY"
 
-function __dns_server_sort() {
-	sort -k2 -g | uniq
+	while read -r line; do
+		dns_server_parse_line ${line} || continue
+
+		print "${format}" "${server}" "${priority}"
+	done < ${DNS_SERVER_CONFIG_FILE}
+
+	return ${EXIT_OK}
 }
 
-function dns_server_list() {
+function dns_server_list_sorted() {
 	[ -r "${DNS_SERVER_CONFIG_FILE}" ] || return ${EXIT_OK}
 
-	local server priority
-	while read server priority; do
-		if [ -n "${server}" ] && [ -n "${priority}" ]; then
-			__dns_server_println "${server}" "${priority}"
-		fi
-	done < ${DNS_SERVER_CONFIG_FILE} | __dns_server_sort
-}
+	local servers=$(
+		# First get all servers from the configuration file.
+		while read -r line; do
+			dns_server_parse_line ${line} || continue
 
-function dns_server_list_no_priority() {
-	local server priority
-	dns_server_list | while read server priority; do
-		echo "${server}"
-	done
+			print "%d %s" "${priority}" "${server}"
+		done < ${DNS_SERVER_CONFIG_FILE}
+
+		# Then get all dynamically assigned DNS servers.
+		dns_server_get_zone_name_servers
+	)
+
+	# Nothing to do if we have got no DNS servers.
+	isset servers || return ${EXIT_OK}
+
+	# Sort everything we have got.
+	servers=$(sort -g -k1 <<< "${servers}")
+
+	# Remove the priority bit.
+	local server server_list
+	while read -r priority server; do
+		list_append server_list "${server}"
+	done <<< "${servers}"
+
+	# Return the list but remove duplicate entries, keeping
+	# the first and removing all others.
+	list_unique ${server_list}
+
+	return ${EXIT_OK}
 }
 
 function dns_server_add() {
@@ -86,35 +114,103 @@ function dns_server_add() {
 
 	local priority=${2}
 	if ! isset priority; then
-		priority=20
+		priority="${DNS_SERVER_DEFAULT_PRIORITY}"
 	fi
 	assert isinteger priority
 
-	(
-		dns_server_list
-		__dns_server_println "${server}" "${priority}"
-	) | __dns_server_sort > ${DNS_SERVER_CONFIG_FILE}.new
+	# Add a new line to the configuration file.
+	print "server=\"%s\" priority=\"%d\"" "${server}" "${priority}" \
+		>> ${DNS_SERVER_CONFIG_FILE}
 
-	mv ${DNS_SERVER_CONFIG_FILE}{.new,}
+	return ${EXIT_OK}
+}
+
+function dns_server_exists() {
+	local entry=${1}
+	assert isset entry
+
+	[ -r "${DNS_SERVER_CONFIG_FILE}" ] || return ${EXIT_FALSE}
+
+	local line ${NETWORK_CONFIG_DNS_SERVER_PARAMS}
+	while read -r line; do
+		dns_server_parse_line ${line} || continue
+
+		[ "${entry}" = "${server}" ] && return ${EXIT_TRUE}
+	done < ${DNS_SERVER_CONFIG_FILE}
+
+	return ${EXIT_FALSE}
 }
 
 function dns_server_remove() {
-	local server=${1}
-	assert isset server
+	local entry=${1}
+	assert isset entry
 
-	local entry priority
-	local entries=$(dns_server_list)
+	# Check if the DNS server configuration file exists.
+	[ -r "${DNS_SERVER_CONFIG_FILE}" ] || return ${EXIT_ERROR}
 
-	while read entry priority; do
+	# Create a tempfile.
+	local tempfile=$(mktemp)
+
+	local line ${NETWORK_CONFIG_DNS_SERVER_PARAMS}
+	while read -r line; do
+		dns_server_parse_line ${line} || continue
+
+		# Skip the line with the server we are searching for.
 		[ "${entry}" = "${server}" ] && continue
-		__dns_server_println "${server}" "${priority}"
-	done <<< ${entries} | __dns_server_sort > ${DNS_SERVER_CONFIG_FILE}
+
+		# Re-add the old line.
+		print "${line}"
+	done < ${DNS_SERVER_CONFIG_FILE} > ${tempfile}
+
+	# Overwrite the old content without the entry that has just been removed.
+	fread "${tempfile}" > ${DNS_SERVER_CONFIG_FILE}
+
+	# Remove the temporary file.
+	rm -f ${tempfile}
+
+	return ${EXIT_OK}
 }
 
 function dns_server_flush() {
 	: > ${DNS_SERVER_CONFIG_FILE}
 }
 
+function dns_server_parse_line() {
+	local arg
+
+	for arg in ${NETWORK_CONFIG_DNS_SERVER_PARAMS}; do
+		assign "${arg}" ""
+	done
+
+	while read -r arg; do
+		case "${arg}" in
+			server=*)
+				server=$(cli_get_val ${arg})
+				;;
+			priority=*)
+				priority=$(cli_get_val ${arg})
+				;;
+		esac
+	done <<< "$(args $@)"
+
+	# The server address must be set.
+	isset server || return ${EXIT_ERROR}
+
+	# The server address must also be a valid IP address.
+	ip_is_valid ${server} || return ${EXIT_ERROR}
+
+	# If priority is set, it must be an integer number.
+	if isset priority; then
+		isinteger priority || return ${EXIT_ERROR}
+
+	# Otherwise assign the default priority.
+	else
+		priority=${DNS_SERVER_DEFAULT_PRIORITY}
+	fi
+
+	return ${EXIT_OK}
+}
+
 # Update resolv.conf(5) when initializing the network.
 init_register dns_generate_resolvconf
 
@@ -149,39 +245,35 @@ function dns_generate_resolvconf() {
 	search_domains=$(list_unique ${search_domains})
 
 	# Write search domains to file.
+	print "# Search domains" >> ${file}
 	for domainname in ${search_domains}; do
 		print "search ${domainname}"
 	done >> ${file}
 
+	print "\n# Nameservers" >> ${file}
+
 	# Add the local resolver as the first DNS server if enabled.
 	if enabled DNS_USE_LOCAL_RESOLVER; then
 		print "nameserver ::1" >> ${file}
 	fi
 
-	# First pull in zone name servers.
-	local server
-	for server in $(dns_get_zone_name_servers); do
-		print "nameserver ${server}"
-	done >> ${file}
-
-	# Dump all DNS servers (if any).
-	local priority
-	dns_server_list | while read server priority; do
+	# Dump all DNS servers.
+	for server in $(dns_server_list_sorted); do
 		print "nameserver ${server}"
 	done >> ${file}
 }
 
-function dns_get_zone_name_servers() {
-	local servers
-	local zone
+function dns_server_get_zone_name_servers() {
+	local priority proto server servers zone
+
 	for zone in $(zones_get_all); do
-		local proto
 		for proto in ${IP_SUPPORTED_PROTOCOLS}; do
-			servers=$(routing_db_get ${zone} ${proto} domain-name-servers)
+			priority=$(routing_db_get ${zone} ${proto} domain-name-servers-priority)
+			isset priority || priority="${DNS_SERVER_DYNAMIC_PRIORITY}"
 
-			local server
+			servers=$(routing_db_get ${zone} ${proto} domain-name-servers)
 			for server in ${servers}; do
-				print "${server}"
+				print "${priority} ${server}"
 			done
 		done
 	done
diff --git a/functions.radvd b/functions.radvd
index 804398e5..7970a54b 100644
--- a/functions.radvd
+++ b/functions.radvd
@@ -114,7 +114,7 @@ function __radvd_config_dns() {
 	# resolver.
 
 	local server servers
-	for server in $(dns_server_list_no_priority); do
+	for server in $(dns_server_list_sorted); do
 		# Filter out non IPv6 addresses.
 		ipv6_is_valid ${server} || continue
 
diff --git a/functions.util b/functions.util
index 68fac1b3..3a4751f4 100644
--- a/functions.util
+++ b/functions.util
@@ -89,12 +89,24 @@ function basename() {
 	echo "${1##*/}"
 }
 
+function format() {
+	local key=${1}
+	assert isset key
+
+	local format=${2}
+	assert isset format
+
+	shift 2
+
+	printf -v "${key}" "${format}" "$@"
+}
+
 function assign() {
 	local key=${1}
 	assert isset key
 	shift
 
-	printf -v "${key}" "%s" "$@"
+	format "${key}" "%s" "$@"
 }
 
 function fread() {
diff --git a/network b/network
index 61dfcdfa..00a4f76d 100755
--- a/network
+++ b/network
@@ -1055,15 +1055,24 @@ function cli_dns() {
 
 	case "${cmd}" in
 		list)
-			__dns_server_println "SERVER" "PRIORITY"
 			dns_server_list
 			exit ${EXIT_OK}
 			;;
 		add)
+			if dns_server_exists ${server}; then
+				error "DNS server '${server}' already exists!"
+				exit ${EXIT_ERROR}
+			fi
+
 			log INFO "Adding new DNS server: ${server}"
 			dns_server_add ${server} ${priority}
 			;;
 		remove)
+			if ! dns_server_exists ${server}; then
+				error "DNS server '${server}' does not exist!"
+				exit ${EXIT_ERROR}
+			fi
+
 			log INFO "Removing DNS server: ${server}"
 			dns_server_remove ${server} ${priority}
 			;;