1 files changed, 7 insertions, 0 deletions

diff --git a/networking/udhcp/dhcpd.c b/networking/udhcp/dhcpd.c
index b67dfc3bc..0f5edb75c 100644
--- a/networking/udhcp/dhcpd.c
+++ b/networking/udhcp/dhcpd.c
@@ -614,6 +614,10 @@ static void send_packet_to_relay(struct dhcp_packet *dhcp_pkt)
         udhcp_send_kernel_packet(dhcp_pkt,
                         server_data.server_nip, SERVER_PORT,
                         dhcp_pkt->gateway_nip, SERVER_PORT,
+        /* Yes, relay agents receive (and send) all their packets on SERVER_PORT,
+         * even those which are clients' requests and would normally
+         * (i.e. without relay) use CLIENT_PORT. See RFC 1542.
+         */
                         server_data.interface);
 }
 
@@ -1025,6 +1029,9 @@ int udhcpd_main(int argc UNUSED_PARAM, char **argv)
                  * socket read inside this call is restarted on caught signals.
                  */
                 bytes = udhcp_recv_kernel_packet(&packet, server_socket);
+//NB: we do not check source port here. Should we?
+//It should be CLIENT_PORT for clients,
+//or SERVER_PORT for relay agents (in which case giaddr must be != 0.0.0.0)
                 if (bytes < 0) {
                         /* bytes can also be -2 ("bad packet data") */
                         if (bytes == -1 && errno != EINTR) {