/**
* DHCP: Sends DHCP-Release message. Releases occupied IP.
*/
void dhcp_send_release(void) {
uint32_t packetsize = sizeof(struct iphdr) +
sizeof(struct udphdr) + sizeof(struct btphdr);
struct btphdr *btph;
dhcp_options_t opt;
btph = (struct btphdr *) (ðer_packet[
sizeof(struct iphdr) + sizeof(struct udphdr)]);
memset(ether_packet, 0, packetsize);
btph -> op = 1;
btph -> htype = 1;
btph -> hlen = 6;
strcpy((char *) btph -> file, "");
memcpy(btph -> chaddr, get_mac_address(), 6);
btph -> ciaddr = htonl(dhcp_own_ip);
memset(&opt, 0, sizeof(dhcp_options_t));
opt.msg_type = DHCPRELEASE;
opt.server_ID = dhcp_server_ip;
opt.flag[DHCP_SERVER_ID] = 1;
dhcp_encode_options(btph -> vend, &opt);
fill_udphdr(ðer_packet[sizeof(struct iphdr)],
sizeof(struct btphdr) + sizeof(struct udphdr),
UDPPORT_BOOTPC, UDPPORT_BOOTPS);
fill_iphdr(ether_packet, sizeof(struct btphdr) +
sizeof(struct udphdr) + sizeof(struct iphdr), IPTYPE_UDP,
dhcp_own_ip, dhcp_server_ip);
send_ipv4(ether_packet, packetsize);
}
/**
* DNS: Sends a standard DNS-query (read request package) to a DNS-server.
* DNS-server respones with host IP or signals some error condition.
* Responses from the server are handled by handle_dns function.
*
* @param fd socket descriptor
* @param domain_name the domain name given as series of labels preceded
* with length(label) and terminated with 0
* <br>(e.g. "\3,w,w,w,\4,h,o,s,t,\3,o,r,g,\0")
* @see handle_dns
*/
static void
dns_send_query(int fd, int8_t * domain_name, uint8_t ip_version)
{
int qry_len = strlen((char *) domain_name) + 5;
int iphdr_len = (ip_version == 4) ? sizeof(struct iphdr) : sizeof(struct ip6hdr);
ip6_addr_t server_ipv6;
uint32_t packetsize = iphdr_len +
sizeof(struct udphdr) + sizeof(struct dnshdr) +
qry_len;
memset(ether_packet, 0, packetsize);
fill_dnshdr(ðer_packet[
iphdr_len + sizeof(struct udphdr)],
domain_name,
ip_version);
fill_udphdr(ðer_packet[iphdr_len],
sizeof(struct dnshdr) +
sizeof(struct udphdr) + qry_len,
UDPPORT_DNSC, UDPPORT_DNSS);
if (ip_version == 4) {
fill_iphdr(ether_packet,
sizeof(struct dnshdr) + sizeof(struct udphdr) +
iphdr_len + qry_len,
IPTYPE_UDP, 0, dns_server_ip);
} else {
memcpy(server_ipv6.addr, dns_server_ipv6, 16);
fill_ip6hdr(ether_packet,
sizeof(struct dnshdr) + sizeof(struct udphdr) + qry_len,
IPTYPE_UDP, get_ipv6_address(),
&server_ipv6);
}
send_ip(fd, ether_packet, packetsize);
}
char *fill_ppk_udpbigport(const struct probing_info *pi, int *size)
{
char *packet = new_packet(IPPROTO_UDP, pi->option, size);
fill_iphdr((struct iphdr *) packet, *size, *size, _pID, pi->ttl,
IPPROTO_UDP, pi->src, pi->dst);
fill_udphdr((struct udphdr *) (packet + sizeof(struct iphdr)),
*size - sizeof(struct iphdr), _SEQ, pi->dport,
*size - sizeof(struct iphdr), pi->src, pi->dst);
return packet;
}
/**
* DHCP: Sends DHCP-Request message. Asks for acknowledgment to occupy IP.
*/
static void
dhcp_send_request(void) {
uint32_t packetsize = sizeof(struct iphdr) +
sizeof(struct udphdr) + sizeof(struct btphdr);
struct btphdr *btph;
dhcp_options_t opt;
memset(ether_packet, 0, packetsize);
btph = (struct btphdr *) (ðer_packet[
sizeof(struct iphdr) + sizeof(struct udphdr)]);
btph -> op = 1;
btph -> htype = 1;
btph -> hlen = 6;
memcpy(btph -> chaddr, get_mac_address(), 6);
memset(&opt, 0, sizeof(dhcp_options_t));
opt.msg_type = DHCPREQUEST;
memcpy(&(opt.requested_IP), &dhcp_own_ip, 4);
opt.flag[DHCP_REQUESTED_IP] = 1;
memcpy(&(opt.server_ID), &dhcp_server_ip, 4);
opt.flag[DHCP_SERVER_ID] = 1;
opt.request_list[DHCP_MASK] = 1;
opt.request_list[DHCP_DNS] = 1;
opt.request_list[DHCP_ROUTER] = 1;
opt.request_list[DHCP_TFTP_SERVER] = 1;
opt.request_list[DHCP_BOOTFILE] = 1;
dhcp_encode_options(btph -> vend, &opt);
fill_udphdr(ðer_packet[sizeof(struct iphdr)],
sizeof(struct btphdr) + sizeof(struct udphdr),
UDPPORT_BOOTPC, UDPPORT_BOOTPS);
fill_iphdr(ether_packet, sizeof(struct btphdr) +
sizeof(struct udphdr) + sizeof(struct iphdr),
IPTYPE_UDP, 0, 0xFFFFFFFF);
send_ipv4(ether_packet, packetsize);
}
