gre: add different per-protocol prefixes to GRE-TAP IPv4/6 tunnel interfaces.

This commit modifies the /lib/netifd/proto/gre.sh script so that, when
GRE-TAP tunnels are created, either IPv4 or IPv6, the prefix before the chosen
interface name contains the "tap" substring, to differentiate them from non-TAP
GRE tunnels.

Right now, both GRE and GRE-TAP tunnel (either IPv4 or IPv6) interfaces defined
in /etc/config/network are named equally ("gre-"+$ifname or "grev6"+$ifname)
upon creation. For instance, the following tunnels:

        config interface 'tuna'
                option peeraddr '172.30.22.1'
                option proto 'gre'

        config interface 'tunb'
                option peeraddr '192.168.233.4'
                option proto 'gretap'

        config interface 'tunc'
                option peer6addr 'fdc5:7c9e:e93d:45af::1'
                option proto 'grev6'

        config interface 'tund'
                option peer6addr 'fdc0:6071:1348:31ff::2'
                option proto 'grev6tap'

are named, respectively, "gre-tuna", "gre-tunb", "grev6-tunc" and "grev6-tund".

The current change makes that each GRE tunnel interface of the four different
types available (gre, gretap, grev6 and grev6tap) gets a different prefix.
Therefore, the abovementioned tunnels will be named, respectively:
"gre4-tuna", "gre4t-tunb", "gre6-tunc" and "gre6t-tund".

This is coherent with other types of virtual interfaces (i.e. PPP, PPPoE, PPPoA)
where the whole protocol name is used. For instance, a PPPoA interface named
"p1" and a PPPoE interface named "p2" will respectively appear as "pppoa-p1"
and "pppoe-p2", not as "ppp-p1" and "ppp-p2").

Since Linux interfaces names are limited to 15 characters, these prefixes leave,
for the worst case (TAP tunnels), 9 characters for the actual name.

Signed-off-by: Roger Pueyo Centelles <[email protected]>

package/network/config/gre/Makefile

@@ -9,7 +9,7 @@ include $(TOPDIR)/rules.mk
 
 PKG_NAME:=gre
 PKG_VERSION:=1
-PKG_RELEASE:=5
+PKG_RELEASE:=6
 PKG_LICENSE:=GPL-2.0
 
 include $(INCLUDE_DIR)/package.mk

package/network/config/gre/files/gre.sh

@@ -84,7 +84,14 @@ gre_setup() {
 
 	[ -z "$df" ] && df="1"
 
-	gre_generic_setup $cfg $mode $ipaddr $peeraddr "gre-$cfg"
+	case "$mode" in
+		gretapip)
+			gre_generic_setup $cfg $mode $ipaddr $peeraddr "gre4t-$cfg"
+			;;
+		*)
+			gre_generic_setup $cfg $mode $ipaddr $peeraddr "gre4-$cfg"
+			;;
+	esac
 }
 
 proto_gre_setup() {
@@ -102,7 +109,7 @@ proto_gretap_setup() {
 	gre_setup $cfg "gretapip"
 
 	json_init
-	json_add_string name "gre-$cfg"
+	json_add_string name "gre4t-$cfg"
 	json_add_boolean link-ext 0
 	json_close_object
 
@@ -155,7 +162,14 @@ grev6_setup() {
 		fi
 	}
 
-	gre_generic_setup $cfg $mode $ip6addr $peer6addr "grev6-$cfg"
+	case "$mode" in
+		gretapip6)
+			gre_generic_setup $cfg $mode $ip6addr $peer6addr "gre6t-$cfg"
+			;;
+		*)
+			gre_generic_setup $cfg $mode $ip6addr $peer6addr "gre6-$cfg"
+			;;
+	esac
 }
 
 proto_grev6_setup() {
@@ -173,7 +187,7 @@ proto_grev6tap_setup() {
 	grev6_setup $cfg "gretapip6"
 
 	json_init
-	json_add_string name "grev6-$cfg"
+	json_add_string name "gre6t-$cfg"
 	json_add_boolean link-ext 0
 	json_close_object
 
@@ -203,7 +217,7 @@ proto_gre_teardown() {
 proto_gretap_teardown() {
 	local cfg="$1"
 
-	gretap_generic_teardown "gre-$cfg"
+	gretap_generic_teardown "gre4t-$cfg"
 }
 
 proto_grev6_teardown() {
@@ -213,7 +227,7 @@ proto_grev6_teardown() {
 proto_grev6tap_teardown() {
 	local cfg="$1"
 
-	gretap_generic_teardown "grev6-$cfg"
+	gretap_generic_teardown "gre6t-$cfg"
 }
 
 gre_generic_init_config() {