uint8_t dhcp_get_ip()
{
uint8_t sockid = SOCKET_INVALID;
// First get a socket
sockid = udp_open(DHCP_CLIENT_PORT);
if (sockid == SOCKET_INVALID)
return 1;
dhcp_send_packet(sockid, DHCP_DISCOVER);
if (dhcp_read_packet(sockid) != DHCP_OFFER)
return 2;
dhcp_send_packet(sockid, DHCP_REQUEST);
if (dhcp_read_packet(sockid) != DHCP_ACK)
return 3;
// Finally close the socket
udp_close(sockid);
return 0;
}
int dhcp_request(uip_ipaddr_t *next_ip, uip_ipaddr_t *server_ip,
const char **bootfile)
{
DhcpPacket out, in;
uint8_t byte;
uint8_t *options;
int remaining;
uint8_t requested[] = { DhcpTagSubnetMask, DhcpTagDefaultRouter };
assert(DhcpMaxPacketSize >= DhcpMinPacketSize);
uint16_t max_size = htonw(DhcpMaxPacketSize);
uint8_t client_id[1 + sizeof(uip_ethaddr)];
client_id[0] = DhcpEthernet;
memcpy(client_id + 1, &uip_ethaddr, sizeof(uip_ethaddr));
// Set up the UDP connection.
uip_ipaddr_t addr;
uip_ipaddr(&addr, 255,255,255,255);
struct uip_udp_conn *conn = uip_udp_new(&addr, htonw(DhcpServerPort));
if (!conn) {
printf("Failed to set up UDP connection.\n");
return 1;
}
uip_udp_bind(conn, htonw(DhcpClientPort));
// Send a DHCP discover packet.
dhcp_prep_packet(&out, rand());
options = out.options;
remaining = sizeof(out.options);
byte = DhcpDiscover;
dhcp_add_option(&options, DhcpTagMessageType, &byte, sizeof(byte),
&remaining);
dhcp_add_option(&options, DhcpTagClientIdentifier, client_id,
sizeof(client_id), &remaining);
dhcp_add_option(&options, DhcpTagParameterRequestList, requested,
sizeof(requested), &remaining);
dhcp_add_option(&options, DhcpTagMaximumDhcpMessageSize,
&max_size, sizeof(max_size), &remaining);
dhcp_add_option(&options, DhcpTagEndOfList, NULL, 0, &remaining);
dhcp_send_packet(conn, "DHCP discover", &out, &in);
// Extract the DHCP server id.
uint32_t server_id;
if (dhcp_process_options(&in, OptionOverloadNone, &dhcp_get_server,
&server_id)) {
printf("Failed to extract server id.\n");
return 1;
}
// We got an offer. Request it.
dhcp_state = DhcpRequesting;
dhcp_prep_packet(&out, rand());
options = out.options;
remaining = sizeof(out.options);
byte = DhcpRequest;
dhcp_add_option(&options, DhcpTagMessageType, &byte, sizeof(byte),
&remaining);
dhcp_add_option(&options, DhcpTagClientIdentifier, client_id,
sizeof(client_id), &remaining);
dhcp_add_option(&options, DhcpTagRequestedIpAddress, &in.your_ip,
sizeof(in.your_ip), &remaining);
dhcp_add_option(&options, DhcpTagParameterRequestList, requested,
sizeof(requested), &remaining);
dhcp_add_option(&options, DhcpTagMaximumDhcpMessageSize,
&max_size, sizeof(max_size), &remaining);
dhcp_add_option(&options, DhcpTagServerIdentifier,
&server_id, sizeof(server_id), &remaining);
dhcp_add_option(&options, DhcpTagEndOfList, NULL, 0, &remaining);
dhcp_send_packet(conn, "DHCP request", &out, &in);
DhcpMessageType type;
if (dhcp_process_options(&in, OptionOverloadNone, &dhcp_get_type,
&type)) {
printf("Failed to extract message type.\n");
dhcp_state = DhcpInit;
return 1;
}
if (type == DhcpNak) {
printf("DHCP request nak-ed by the server.\n");
dhcp_state = DhcpInit;
return 1;
}
// The server acked, completing the transaction.
dhcp_state = DhcpBound;
uip_udp_remove(conn);
// Apply the settings.
if (dhcp_process_options(&in, OptionOverloadNone,
&dhcp_apply_options, NULL)) {
dhcp_state = DhcpInit;
return 1;
}
int bootfile_size = sizeof(in.bootfile_name) + 1;
char *file = xmalloc(bootfile_size);
file[bootfile_size - 1] = 0;
memcpy(file, in.bootfile_name, sizeof(in.bootfile_name));
*bootfile = file;
uip_ipaddr(next_ip, in.server_ip >> 0, in.server_ip >> 8,
in.server_ip >> 16, in.server_ip >> 24);
uip_ipaddr(server_ip, server_id >> 0, server_id >> 8,
server_id >> 16, server_id >> 24);
uip_ipaddr_t my_ip;
uip_ipaddr(&my_ip, in.your_ip >> 0, in.your_ip >> 8,
in.your_ip >> 16, in.your_ip >> 24);
uip_sethostaddr(&my_ip);
return 0;
}
