void check_packet_protocol(sr_router* router, struct ip* ip_header, byte* payload, uint16_t payload_len, interface_t* intf, byte* ip_packet) {
if(ip_header->ip_p == IP_PROTOCOL_ICMP) {
//icmp
printf(" ** ip_handle_packet(..) protocol: ICMP \n");
icmp_handle_packet(router, payload, payload_len, ip_header, intf);
} else if(ip_header->ip_p == IP_PROTOCOL_TCP) {
//tcp
printf(" ** ip_handle_packet(..) protocol: TCP \n");
sr_transport_input(ip_packet);
} else if(ip_header->ip_p == IP_PROTOCOL_UDP) {
//udp
printf(" ** ip_handle_packet(..) protocol: UDP \n");
//udp_handle_packet(payload, ip_header, intf);
printf(" ** ip_handle_packet(..) protocol: Error! Not supported. Dropping and sending ICMP response: port unreachable \n");
uint8_t code = ICMP_TYPE_CODE_DST_UNREACH_PORT;
icmp_type_dst_unreach_send(&code, ip_packet, (uint16_t*)&ip_header->ip_len, ip_header);
} else if(ip_header->ip_p == IP_PROTOCOL_OSPF) {
//ospf
printf(" ** ip_handle_packet(..) protocol: OSPF \n");
pwospf_handle_packet(payload,
payload_len,
ip_header,
intf,
router);
}else {
//otherwise
printf(" ** ip_handle_packet(..) protocol: Error! Not supported. Dropping and sending ICMP response \n");
uint8_t code = ICMP_TYPE_CODE_DST_UNREACH_PROTOCOL;
icmp_type_dst_unreach_send(&code, ip_packet, (uint16_t*)&ip_header->ip_len, ip_header);
}
}
int handle_ip_pkt(struct sr_instance* sr, uint8_t* Pkt, char* interface, unsigned int len, uint8_t srcMAC[]) {
//actually I have to pass in a uint8_t* packet not an sr_ip_pkt...
/*
Extract the IP header
Header actions:
1) check the IP checksum
-> discard if wrong
2) check if TTL expired
-> send ICMP type 11 (0)
3) check if it is our message
-> if yes jump to "OURS:"
Not Ours:
1) Find the next hop in rtable
2) Decrement TTL, recalculate Checksum
3) Assemble new packet
4) Send on correct interface
OURS:
1) Check type of packet
-> ICMP
-> UDP/TCP
ICMP:
1) Check type
2) respond as appropriate
UDP/TCP
1) Pass up the stack
*/
assert(Pkt);
assert(sr);
assert(interface);
//struct sr_router* subsystem = (struct sr_router*)sr_get_subsystem(sr);
struct sr_vns_if* myIntf = sr_get_interface(sr, interface);
uint32_t myIP = myIntf->ip;
struct ip* pktHdr = (struct ip*)Pkt;
uint8_t* payload = (uint8_t*)malloc_or_die(len - 20);
uint8_t* ptr = Pkt + 20;
memcpy(payload, ptr, len-20);
uint32_t originIP = pktHdr->ip_src.s_addr;
//first thing is to update ARP - no point wasiting useful information is there!
time_t now = time(NULL);
int checkArp;
checkArp = find_and_update(sr, originIP, srcMAC, now);
if(pktHdr->ip_hl != 5) {
//means there were IP options so unerachable (host or network?)
printf("@@@@@@@@@@@@@@@@@@@@@@@@@@ IP hdr length was %u. Should have been 5 (e.g. 20 bytes)\n", pktHdr->ip_hl);
uint8_t* data = (uint8_t*)malloc_or_die(28);
memcpy(data, Pkt, 28);
int tmp;
tmp = create_ICMP_pkt(sr, interface, originIP, 3, 1, 0, 0, data, 28);
return -3;
}
if(cksum((uint8_t*)pktHdr, 20)) {
printf("@@@@@@@@@@@@@@@@@@@@@@ CHECKSUM 0x%hx WAS INVALID SO WE WILL DROP THE PACKET\n", pktHdr->ip_sum);
return -2;
}
if(pktHdr->ip_ttl < 2) {
printf("@@@@@@@@@@@@@@@@@@@@@@ TTL has expired so we will send back an ICMP\n");
//get the data (IP hdr + 8 bytes of packet)
uint8_t* data = (uint8_t*)malloc_or_die(28);
memcpy(data, Pkt, 28);
int tmp;
tmp = create_ICMP_pkt(sr, interface, originIP, 11, 0, 0, 0, data, 28);
return -1;
}
if(check_my_interface(sr, (uint32_t)pktHdr->ip_dst.s_addr)) {
// printf("This is my packet so I will process it\n");
switch(pktHdr->ip_p) {
case IPPROTO_ICMP:
;
//printf("\nThis is an IP ICMP packet of length %d\n", len);
// printf("After removing the IP header we are left with %d bytes\n", datalen);
int datalen = len - sizeof(struct ip);
uint8_t* ICMP = (uint8_t*) malloc_or_die(datalen);
//ICMP = array_cpy(Pkt->payload, datalen);
memcpy(ICMP, payload, datalen);
int tmp;
tmp = process_ICMP_pkt(sr, interface, originIP, ICMP, datalen);
return tmp;
case IPPROTO_TCP:
printf("TCP packet sent up the stack\n");
sr_transport_input(Pkt);
return 1;
default:
return 0;
}
}
else {
//printf("********** Not my packet, so I will forward it\n");
return 3;
}
return 0;
}
