void tprint_nic(char* desc, CnetNICaddr addr) {
char str[17];
CNET_format_nicaddr(str, addr);
//printf("%s: %s\n", desc, str);
}
/*
* Handle arp packet
*/
int handle_arp_packet(ARP_PACKET *arp_packet)
{
bool addtoarptable = false;
char sourmac[18]; //source hardware address
const char *sourip = network_display_address(arp_packet->sour_ip);
CNET_format_nicaddr(sourmac, arp_packet->sour_mac);
printf("ARP packet source MAC: %s \n", sourmac);
//handle arp ethernet
if (arp_packet->htype == ETH_CODE){
if (arp_packet->hlen == LEN_NICADDR){
if (arp_packet->ptype == IP_CODE){
if (arp_packet->plen == IP_ADDRLEN){
int pos = 0;
pos = query_arp_table(arp_packet->sour_ip);
if (pos != -1){
printf("Update ARP table - source IP: %s \n", sourip);
update_arp_table(arp_packet->sour_mac, pos);
addtoarptable = true;
} else {
printf("Add source IP to ARP table: %s \n", sourip);
IPAddr sour_ip = arp_packet->sour_ip;
add_arp_table(sour_ip, arp_packet->sour_mac);
CHECK(network_unpause_destination(sour_ip));
}
if (arp_packet->dest_ip == network_local_address()){
if (!addtoarptable){
printf("Add source IP to ARP table: %s \n", sourip);
IPAddr sour_ip = arp_packet->sour_ip;
add_arp_table(sour_ip, arp_packet->sour_mac);
}
if (arp_packet->opcode == ARP_REQUEST_CODE){
CnetNICaddr nicAddress;
IPAddr ip1 = 0, ip2 = 0;
printf("ARP response IP: %s \n", sourip);
arp_packet->opcode = ARP_REPLY_CODE;
memcpy(nicAddress, arp_packet->sour_mac, sizeof(CnetNICaddr));
memcpy(arp_packet->sour_mac, linkinfo[1].nicaddr, sizeof(CnetNICaddr));
memcpy(arp_packet->dest_mac, nicAddress, sizeof(CnetNICaddr));
ip1 = arp_packet->sour_ip;
ip2 = network_local_address();
arp_packet->sour_ip = ip2;
arp_packet->dest_ip = ip1;
arp_request(arp_packet);
}
}
} else {
printf("IP address length error! (should be equal to 4) \n");
return -1;
}
} else {
printf("Ethernet protocol error! (should be IPv4) \n");
return -1;
}
} else {
printf("MAC address length error! (should be equal to 6) \n");
return -1;
}
} else {
printf("Hardware protocol error! (should be Ethernet) \n");
return -1;
}
return 0;
}
