/* Send a packet to a specific mac address and ip address by creating our own ip packet */
static void send_packet_to_client(struct dhcp_packet *dhcp_pkt, int force_broadcast)
{
const uint8_t *chaddr;
uint32_t ciaddr;
// Was:
//if (force_broadcast) { /* broadcast */ }
//else if (dhcp_pkt->ciaddr) { /* unicast to dhcp_pkt->ciaddr */ }
//else if (dhcp_pkt->flags & htons(BROADCAST_FLAG)) { /* broadcast */ }
//else { /* unicast to dhcp_pkt->yiaddr */ }
// But this is wrong: yiaddr is _our_ idea what client's IP is
// (for example, from lease file). Client may not know that,
// and may not have UDP socket listening on that IP!
// We should never unicast to dhcp_pkt->yiaddr!
// dhcp_pkt->ciaddr, OTOH, comes from client's request packet,
// and can be used.
if (force_broadcast
|| (dhcp_pkt->flags & htons(BROADCAST_FLAG))
|| dhcp_pkt->ciaddr == 0
) {
log1("Broadcasting packet to client");
ciaddr = INADDR_BROADCAST;
chaddr = MAC_BCAST_ADDR;
} else {
log1("Unicasting packet to client ciaddr");
ciaddr = dhcp_pkt->ciaddr;
chaddr = dhcp_pkt->chaddr;
}
udhcp_send_raw_packet(dhcp_pkt,
/*src*/ server_config.server_nip, SERVER_PORT,
/*dst*/ ciaddr, CLIENT_PORT, chaddr,
server_config.ifindex);
}
/* send a packet to a specific arp address and ip address by creating our own ip packet */
static int send_packet_to_client(struct dhcpMessage *payload, int force_broadcast)
{
const uint8_t *chaddr;
uint32_t ciaddr;
if (force_broadcast) {
DEBUG("broadcasting packet to client (NAK)");
ciaddr = INADDR_BROADCAST;
chaddr = MAC_BCAST_ADDR;
} else if (payload->ciaddr) {
DEBUG("unicasting packet to client ciaddr");
ciaddr = payload->ciaddr;
chaddr = payload->chaddr;
} else if (payload->flags & htons(BROADCAST_FLAG)) {
DEBUG("broadcasting packet to client (requested)");
ciaddr = INADDR_BROADCAST;
chaddr = MAC_BCAST_ADDR;
} else {
DEBUG("unicasting packet to client yiaddr");
ciaddr = payload->yiaddr;
chaddr = payload->chaddr;
}
return udhcp_send_raw_packet(payload,
/*src*/ server_config.server, SERVER_PORT,
/*dst*/ ciaddr, CLIENT_PORT, chaddr,
server_config.ifindex);
}
