add GetInnerPeerAddr (#33)

1 files changed, 24 insertions, 0 deletions

diff --git a/dhcpv6/dhcpv6relay.go b/dhcpv6/dhcpv6relay.go
index d7dc4b9..513d25a 100644
--- a/dhcpv6/dhcpv6relay.go
+++ b/dhcpv6/dhcpv6relay.go
@@ -143,3 +143,27 @@ func (d *DHCPv6Relay) GetInnerMessage() (DHCPv6, error) {
 		}
 	}
 }
+
+// GetInnerPeerAddr returns the peer address in the inner most relay info
+// header, this is typically the IP address of the client making the request.
+func (r *DHCPv6Relay) GetInnerPeerAddr() (net.IP, error) {
+	var (
+		p   DHCPv6
+		err error
+	)
+	p = r
+	hops := r.HopCount()
+	addr := r.PeerAddr()
+	for i := uint8(0); i < hops; i++ {
+		p, err = DecapsulateRelay(p)
+		if err != nil {
+			return nil, err
+		}
+		if p.IsRelay() {
+			addr = p.(*DHCPv6Relay).PeerAddr()
+		} else {
+			return nil, fmt.Errorf("Wrong Hop count")
+		}
+	}
+	return addr, nil
+}