Add support for copying relay options

Signed-off-by: kevin <kworm@missouri-telecom.com>

2 files changed, 13 insertions, 0 deletions

diff --git a/dhcpv4/dhcpv4.go b/dhcpv4/dhcpv4.go
index f85fe2e..d3890c5 100644
--- a/dhcpv4/dhcpv4.go
+++ b/dhcpv4/dhcpv4.go
@@ -262,6 +262,7 @@ func NewReplyFromRequest(request *DHCPv4, modifiers ...Modifier) (*DHCPv4, error
 	return New(PrependModifiers(modifiers,
 		WithReply(request),
 		WithGatewayIP(request.GatewayIPAddr),
+		WithRelayOptions(request),
 	)...)
 }
 
diff --git a/dhcpv4/modifiers.go b/dhcpv4/modifiers.go
index 16d1d57..168b178 100644
--- a/dhcpv4/modifiers.go
+++ b/dhcpv4/modifiers.go
@@ -43,6 +43,18 @@ func WithGatewayIP(ip net.IP) Modifier {
 	}
 }
 
+//WithRelayOptions copies the relay options from the request to the reply
+func WithRelayOptions(request *DHCPv4) Modifier {
+	return func(d *DHCPv4) {
+		// If request has Relay Agent Info copy it to the reply
+		if request.Options.Has(OptionRelayAgentInformation) {
+			relayopt := request.Options.Get(OptionRelayAgentInformation)
+			opt := OptGeneric(OptionRelayAgentInformation, relayopt)
+			d.Options.Update(opt)
+		}
+	}
+}
+
 // WithReply fills in opcode, hwtype, xid, clienthwaddr, flags, and gateway ip
 // addr from the given packet.
 func WithReply(request *DHCPv4) Modifier {