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/internal/message_convert.go

@@ -0,0 +1,58 @@
+package internal
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"net/netip"
+
+	firewallManager "github.com/netbirdio/netbird/client/firewall/manager"
+	mgmProto "github.com/netbirdio/netbird/management/proto"
+)
+
+func convertToFirewallProtocol(protocol mgmProto.RuleProtocol) (firewallManager.Protocol, error) {
+	switch protocol {
+	case mgmProto.RuleProtocol_TCP:
+		return firewallManager.ProtocolTCP, nil
+	case mgmProto.RuleProtocol_UDP:
+		return firewallManager.ProtocolUDP, nil
+	case mgmProto.RuleProtocol_ICMP:
+		return firewallManager.ProtocolICMP, nil
+	case mgmProto.RuleProtocol_ALL:
+		return firewallManager.ProtocolALL, nil
+	default:
+		return "", fmt.Errorf("invalid protocol type: %s", protocol.String())
+	}
+}
+
+func convertPortInfo(portInfo *mgmProto.PortInfo) (*firewallManager.Port, error) {
+	if portInfo == nil {
+		return nil, errors.New("portInfo cannot be nil")
+	}
+
+	if portInfo.GetPort() != 0 {
+		return firewallManager.NewPort(int(portInfo.GetPort()))
+	}
+
+	if portInfo.GetRange() != nil {
+		return firewallManager.NewPort(int(portInfo.GetRange().Start), int(portInfo.GetRange().End))
+	}
+
+	return nil, fmt.Errorf("invalid portInfo: %v", portInfo)
+}
+
+func convertToIP(rawIP []byte) (netip.Addr, error) {
+	if rawIP == nil {
+		return netip.Addr{}, errors.New("input bytes cannot be nil")
+	}
+
+	if len(rawIP) != net.IPv4len && len(rawIP) != net.IPv6len {
+		return netip.Addr{}, fmt.Errorf("invalid IP length: %d", len(rawIP))
+	}
+
+	if len(rawIP) == net.IPv4len {
+		return netip.AddrFrom4([4]byte(rawIP)), nil
+	}
+
+	return netip.AddrFrom16([16]byte(rawIP)), nil
+}