Feature/port forwarding client ingress (#3242)

Client-side forward handling

Co-authored-by: Viktor Liu <17948409+lixmal@users.noreply.github.com>

---------

Co-authored-by: Viktor Liu <17948409+lixmal@users.noreply.github.com>

client/server/forwardingrules.go

@@ -0,0 +1,54 @@
+package server
+
+import (
+	"context"
+
+	firewall "github.com/netbirdio/netbird/client/firewall/manager"
+	"github.com/netbirdio/netbird/client/proto"
+)
+
+func (s *Server) ForwardingRules(context.Context, *proto.EmptyRequest) (*proto.ForwardingRulesResponse, error) {
+	s.mutex.Lock()
+	defer s.mutex.Unlock()
+
+	rules := s.statusRecorder.ForwardingRules()
+	responseRules := make([]*proto.ForwardingRule, 0, len(rules))
+	for _, rule := range rules {
+		respRule := &proto.ForwardingRule{
+			Protocol:           string(rule.Protocol),
+			DestinationPort:    portToProto(rule.DestinationPort),
+			TranslatedAddress:  rule.TranslatedAddress.String(),
+			TranslatedHostname: s.hostNameByTranslateAddress(rule.TranslatedAddress.String()),
+			TranslatedPort:     portToProto(rule.TranslatedPort),
+		}
+		responseRules = append(responseRules, respRule)
+
+	}
+
+	return &proto.ForwardingRulesResponse{Rules: responseRules}, nil
+}
+
+func (s *Server) hostNameByTranslateAddress(ip string) string {
+	hostName, ok := s.statusRecorder.PeerByIP(ip)
+	if !ok {
+		return ip
+	}
+
+	return hostName
+}
+
+func portToProto(port firewall.Port) *proto.PortInfo {
+	var portInfo proto.PortInfo
+
+	if !port.IsRange {
+		portInfo.PortSelection = &proto.PortInfo_Port{Port: uint32(port.Values[0])}
+	} else {
+		portInfo.PortSelection = &proto.PortInfo_Range_{
+			Range: &proto.PortInfo_Range{
+				Start: uint32(port.Values[0]),
+				End:   uint32(port.Values[1]),
+			},
+		}
+	}
+	return &portInfo
+}