datapath: remove 2005 route table for ipv4 only

This reverts commit 3ed62d5 partially and only removes ipv4 2005 route
table.

Fixes: #21954

Signed-off-by: Zhichuan Liang <gray.liang@isovalent.com>

bpf/init.sh

@@ -103,8 +103,7 @@ function move_local_rules()
 
 function setup_proxy_rules()
 {
-	# Any packet from an ingress proxy uses a separate routing table that routes
-	# the packet back to the cilium host device.
+	# TODO(brb): remove $PROXY_RT_TABLE -related code in v1.15
 	from_ingress_rulespec="fwmark 0xA00/0xF00 pref 10 lookup $PROXY_RT_TABLE"
 
 	# Any packet to an ingress or egress proxy uses a separate routing table
@@ -118,27 +117,16 @@ function setup_proxy_rules()
 			if [ -z "$(ip -4 rule list $to_proxy_rulespec)" ]; then
 				ip -4 rule add $to_proxy_rulespec
 			fi
-			if [ "$ENDPOINT_ROUTES" = "true" ]; then
-				if [ ! -z "$(ip -4 rule list $from_ingress_rulespec)" ]; then
-					ip -4 rule delete $from_ingress_rulespec
-				fi
-			else
-				if [ -z "$(ip -4 rule list $from_ingress_rulespec)" ]; then
-					ip -4 rule add $from_ingress_rulespec
-				fi
-			fi
+
+			ip -4 rule delete $from_ingress_rulespec || true
 		fi
 
 		# Traffic to the host proxy is local
 		ip route replace table $TO_PROXY_RT_TABLE local 0.0.0.0/0 dev lo
-		# Traffic from ingress proxy goes to Cilium address space via the cilium host device
-		if [ "$ENDPOINT_ROUTES" = "true" ]; then
-			ip route delete table $PROXY_RT_TABLE $IP4_HOST/32 dev $HOST_DEV1 2>/dev/null || true
-			ip route delete table $PROXY_RT_TABLE default via $IP4_HOST 2>/dev/null || true
-		else
-			ip route replace table $PROXY_RT_TABLE $IP4_HOST/32 dev $HOST_DEV1
-			ip route replace table $PROXY_RT_TABLE default via $IP4_HOST
-		fi
+
+		# The $PROXY_RT_TABLE is no longer in use, so delete it
+		ip route delete table $PROXY_RT_TABLE $IP4_HOST/32 dev $HOST_DEV1 2>/dev/null || true
+		ip route delete table $PROXY_RT_TABLE default via $IP4_HOST 2>/dev/null || true
 	else
 		ip -4 rule del $to_proxy_rulespec 2> /dev/null || true
 		ip -4 rule del $from_ingress_rulespec 2> /dev/null || true