void sr_handlepacket(struct sr_instance* sr,
uint8_t * packet/* lent */,
unsigned int len,
char* interface/* lent */)
{
/* REQUIRES */
assert(sr);
assert(packet);
assert(interface);
printf("*** -> Received packet of length %d \n",len);
if (ethertype(packet) == ethertype_arp) { /* ARP packet */
struct sr_arp_hdr *arpHeader = (struct sr_arp_hdr *) (packet + sizeof(struct sr_ethernet_hdr));
if (is_broadcast_mac(packet) || we_are_dest(sr, arpHeader->ar_tip)) {
/* Process only broadcasted packets or packets meant for me */
processArp(sr, packet, len, interface);
}
} else if (ethertype(packet) == ethertype_ip) { /* IP packet */
struct sr_ip_hdr *ipHeader = (struct sr_ip_hdr *) (packet + sizeof(struct sr_ethernet_hdr));
/* Ignore invalid packets */
if (!is_sane_ip_packet(packet, len)) {
return;
}
/* If NAT is enabled, do an address translation */
if (sr->natEnable) {
int failed = sr_nat_translate_packet(sr, packet, len, interface);
if (failed) {
/* packet could not be translated. Drop it */
return;
}
}
if (we_are_dest(sr, ipHeader->ip_dst)) {
/* We are destination */
processIP(sr, packet, len, interface);
} else {
/* We are not destination. Forward it. */
processForward(sr, packet, len, interface);
}
}
}
uint8_t is_multi_broadcast_mac(const uint8_t *mac)
{
return (is_broadcast_mac(mac) ||
is_ipv4_multicast_mac(mac) ||
is_ipv6_multicast_mac(mac));
}