int dns_init_perthread(void* buf, macaddr_t *src,
macaddr_t *gw, UNUSED port_h_t dst_port,
UNUSED void **arg_ptr)
{
memset(buf, 0, MAX_PACKET_SIZE);
struct ether_header *eth_header = (struct ether_header *) buf;
make_eth_header(eth_header, src, gw);
struct ip *ip_header = (struct ip*)(ð_header[1]);
uint16_t len = htons(sizeof(struct ip) + sizeof(struct udphdr) +
dns_packet_len);
make_ip_header(ip_header, IPPROTO_UDP, len);
struct udphdr *udp_header = (struct udphdr*)(&ip_header[1]);
len = sizeof(struct udphdr) + dns_packet_len;
make_udp_header(udp_header, zconf.target_port, len);
char* payload = (char*)(&udp_header[1]);
module_dns.packet_length = sizeof(struct ether_header) + sizeof(struct ip)
+ sizeof(struct udphdr) + dns_packet_len;
assert(module_dns.packet_length <= MAX_PACKET_SIZE);
memcpy(payload, dns_packet, dns_packet_len);
return EXIT_SUCCESS;
}
void ip_handle_packet( sr_router* router,
byte* ip_packet,
interface_t* intf ) {
printf(" ** ip_handle_packet(..) called \n");
// construct ip header
struct ip* ip_header = make_ip_header(ip_packet);
byte* ip_header_raw = (byte*) malloc_or_die(ip_header->ip_hl * 4);
memcpy(ip_header_raw, ip_packet, ip_header->ip_hl * 4);
// check if ip header is correct
bool ret = check_ip_header(ip_header, ip_header_raw);
if(ret == TRUE) {
printf(" ** ip_handle_packet(..) header sanity checks passed\n");
// display ip header
printf(" ** ip_handle_packet(..) packet contents \n");
display_ip_header(ip_header);
// get payload
uint16_t payload_len = ip_header->ip_len - (ip_header->ip_hl * 4);
printf(" ** ip_handle_packet(..) Payload size %u bytes \n", payload_len);
byte* payload = (byte*) malloc_or_die(payload_len);
memcpy(payload, ip_packet + (ip_header->ip_hl * 4), payload_len);
//free(ip_header_raw);
// check destination
printf(" ** ip_handle_packet(..) checking packet destination \n");
// check if spf broadcast packet
char* all_spf_routers = ALL_SPF_ROUTERS_IP;
if(check_packet_destination(ip_header->ip_dst, router) == TRUE || ip_header->ip_dst.s_addr == make_ip_addr(all_spf_routers)) {
printf(" ** ip_handle_packet(..) yes I'm the destination \n");
// check if ttl expired
/* if(ip_header->ip_ttl == 1) {
printf(" ** ip_handle_packet(..) ttl expired, sending ICMP ttl error message \n");
uint8_t code = ICMP_TYPE_CODE_TTL_TRANSIT;
icmp_type_ttl_send(&code, payload, (uint8_t*)&ip_header->ip_len, ip_header);
} else*/ {
// check protocol
printf(" ** ip_handle_packet(..) checking protocol \n");
check_packet_protocol(router, ip_header, payload, payload_len, intf, ip_packet);
}
} else {
printf(" ** ip_handle_packet(..) no I'm not the destination, send to ip lookup \n");
ip_header->ip_len = htons((ip_header->ip_len));
ip_header->ip_off = htons((ip_header->ip_off));
ip_header->ip_id = htons((ip_header->ip_id));
ip_header->ip_sum = htons((ip_header->ip_sum));
ip_look_up_reply(ip_packet, ip_header, intf);
}
}
else
printf(" ** ip_handle_packet(..) header sanity checks failed\n");
//free(ip_packet);
//free(ip_header);
//free(ip_header_raw);
}
int synscan_init_perthread(void* buf, macaddr_t *src,
macaddr_t *gw, port_h_t dst_port)
{
memset(buf, 0, MAX_PACKET_SIZE);
struct ether_header *eth_header = (struct ether_header *) buf;
make_eth_header(eth_header, src, gw);
struct ip *ip_header = (struct ip*)(ð_header[1]);
uint16_t len = htons(sizeof(struct ip) + sizeof(struct tcphdr));
make_ip_header(ip_header, IPPROTO_TCP, len);
struct tcphdr *tcp_header = (struct tcphdr*)(&ip_header[1]);
make_tcp_header(tcp_header, dst_port);
return EXIT_SUCCESS;
}
