void sr_print_if_list(struct sr_router* sr)
{
struct sr_if* if_walker = 0;
if(sr->if_list == 0)
{
printf(" Interface list empty \n");
return;
}
if_walker = sr->if_list;
sr_print_if(if_walker);
while(if_walker->next)
{
if_walker = if_walker->next;
sr_print_if(if_walker);
}
} /* -- sr_print_if_list -- */
void sr_print_if_list(struct sr_instance* sr)
{
struct sr_vns_if* if_walker = 0;
struct sr_router* sub = (struct sr_router*)sr_get_subsystem(sr);
if(sub->if_list == 0)
{
printf(" Interface list empty \n");
return;
}
if_walker = sub->if_list;
sr_print_if(if_walker);
while(if_walker->next)
{
if_walker = if_walker->next;
sr_print_if(if_walker);
}
} /* -- sr_print_if_list -- */
/*---------------------------------------------------------------------
* Method: process_arp_packet(struct sr_instance* sr,
uint8_t *packet_buffer,
unsigned int len,
char* interface)
* Scope: Global
*
* function to process the arp packet
*
*---------------------------------------------------------------------*/
int process_arp_packet(
struct sr_instance* sr,
uint8_t *packet_buffer,
unsigned int len,
char* interface) {
assert(sr);
assert(packet_buffer);
assert(interface);
int etherLen = sizeof(sr_ethernet_hdr_t); //ethernet header size
int ipLen = sizeof(sr_ip_hdr_t); //ip header length
int arpLen = sizeof(sr_arp_hdr_t); //arp header length
if (len < etherLen + arpLen) {
fprintf(stderr, "Error: ARP header - insufficient length\n");
return -1;
}
printf("ARP Packet Processing Initiated\n");
// print_hdr_arp(packet + sizeof(sr_ethernet_hdr_t));
// Create ARP Header and find interface
sr_arp_hdr_t* arp_header = (sr_arp_hdr_t*)(packet_buffer + etherLen);
struct sr_if* my_interface = sr_find_interface(sr, arp_header->ar_tip);
if (my_interface) {
printf("Found Interface: ");
sr_print_if(my_interface);
if (strcmp(my_interface->name, interface) == 0) {
printf("Interface name's match up\n");
unsigned short op_code = ntohs(arp_header->ar_op);
if (op_code == arp_op_reply) { // Process ARP Reply
printf("Processing ARP Reply\n");
// See if there's an ARP request in the queue.
struct sr_arpreq* req = sr_arpcache_insert(
&(sr->cache), arp_header->ar_sha, arp_header->ar_sip);
// Forward all packets waiting on req if req exists.
struct sr_packet* pckt = req ? req->packets : NULL;
for (; pckt != NULL; pckt = pckt->next) {
eth_frame_send_with_mac(
sr, pckt->buf, pckt->len, arp_header->ar_sha, pckt->iface);
}
} else if (op_code == arp_op_request) { // Process ARP Request
printf("Processing ARP Request\n");
// Set the target to the incoming ARP source.
memcpy(arp_header->ar_tha, arp_header->ar_sha, ETHER_ADDR_LEN);
arp_header->ar_tip = arp_header->ar_sip;
// Set the source to this interface.
memcpy(arp_header->ar_sha, my_interface->addr, ETHER_ADDR_LEN);
arp_header->ar_sip = my_interface->ip;
// Set ethernet frame MAC information
sr_ethernet_hdr_t* ethernet_hdr = (sr_ethernet_hdr_t*)(packet_buffer);
memcpy(ethernet_hdr->ether_dhost, arp_header->ar_tha, ETHER_ADDR_LEN);
memcpy(ethernet_hdr->ether_shost, arp_header->ar_sha, ETHER_ADDR_LEN);
// Send the packet back on it's way.
arp_header->ar_op = htons(arp_op_reply);
printf("Sending out ARP Reply\n");
sr_send_packet(sr, packet_buffer, len, interface);
} else {
fprintf(stderr, "ARP Op Code Unknown: (%d)\n", arp_header->ar_op);
return -1;
}
} else {
fprintf(stderr, "ARP interface names didn't match: %s, %s\n",
my_interface->name, interface);
return -1;
}
} else {
printf("ARP interface not found\n");
}
return 0;
}
