//----------------------------------------------------------------------------
//Init of DHCP client port
void dhcp_init (void)
{
DHCP_DEBUG("\r\nIP %1i.%1i.%1i.%1i\r\n", myip[0] , myip[1] , myip[2] , myip[3]);
//Port in Anwendungstabelle eintragen für eingehende DHCP Daten!
add_udp_app (DHCP_CLIENT_PORT, (void(*)(unsigned char))dhcp_get);
dhcp_state = DHCP_STATE_IDLE;
(*((unsigned long*)&myip[0])) = IP(0,0,0,0);
(*((unsigned long*)&dhcp_offer_ip[0])) = IP(10,42,23,99);
return;
}
//----------------------------------------------------------------------------
// Configure this client by DHCP
unsigned char dhcp (void)
{
unsigned char timeout_cnt;
timeout_cnt = 0;
if ( (dhcp_state == DHCP_STATE_FINISHED ) &&
(dhcp_lease < 600) )
{
dhcp_state = DHCP_STATE_SEND_REQUEST;
}
do
{
if ( timeout_cnt > 3 )
{
dhcp_state = DHCP_STATE_ERR;
DHCP_DEBUG("DHCP timeout\r\n");
return (1);
}
switch (dhcp_state)
{
case DHCP_STATE_IDLE:
dhcp_message(DHCPDISCOVER);
gp_timer = 5;
break;
case DHCP_STATE_DISCOVER_SENT:
if (gp_timer == 0)
{
dhcp_state = DHCP_STATE_IDLE;
timeout_cnt++;
}
break;
case DHCP_STATE_OFFER_RCVD:
timeout_cnt = 0;
dhcp_state = DHCP_STATE_SEND_REQUEST;
break;
case DHCP_STATE_SEND_REQUEST:
gp_timer = 5;
dhcp_message(DHCPREQUEST);
break;
case DHCP_STATE_REQUEST_SENT:
if (gp_timer == 0)
{
dhcp_state = DHCP_STATE_SEND_REQUEST;
timeout_cnt++;
}
break;
case DHCP_STATE_ACK_RCVD:
DHCP_DEBUG("LEASE %2x%2x%2x%2x\r\n", cache.lease[0],cache.lease[1],cache.lease[2],cache.lease[3]);
dhcp_lease = (unsigned long)cache.lease[0] << 24 | (unsigned long)cache.lease[1] << 16 | (unsigned long)cache.lease[2] << 8 |(unsigned long)cache.lease[3];
(*((unsigned long*)&netmask[0])) = (*((unsigned long*)&cache.netmask[0]));
(*((unsigned long*)&router_ip[0])) = (*((unsigned long*)&cache.router_ip[0]));
#if USE_DNS
(*((unsigned long*)&dns_server_ip[0])) = (*((unsigned long*)&cache.dns1_ip[0]));
#endif
dhcp_state = DHCP_STATE_FINISHED;
break;
case DHCP_STATE_NAK_RCVD:
dhcp_state = DHCP_STATE_IDLE;
break;
}
eth_get_data();
}
while ( dhcp_state != DHCP_STATE_FINISHED );
return(0);
}
//----------------------------------------------------------------------------
//Wertet message vom DHCP Server aus
// DHCP packets: 20 Bytes IP Header, 8 Bytes UDP_Header,
// DHCP fixed fields 236 Bytes, min 312 Bytes options -> 576 Bytes min.
void dhcp_get (void)
{
struct dhcp_msg *msg;
struct IP_Header *ip;
unsigned char *p;
unsigned int i;
ip = (struct IP_Header *)ð_buffer[IP_OFFSET];
if ( htons(ip->IP_Pktlen) > MTU_SIZE )
{
DHCP_DEBUG("DHCP too big, discarded\r\n");
return;
}
p = &cache.type; //clear the cache
for (i=0; i<sizeof(cache); i++)
{
p[i] = 0;
}
// set pointer of DHCP message to beginning of UDP data
msg = (struct dhcp_msg *)ð_buffer[UDP_DATA_START];
//check the id
if ( (msg->xid[0] != MYMAC6) ||
(msg->xid[1] != MYMAC5) ||
(msg->xid[2] != MYMAC4) ||
(msg->xid[3] != MYMAC3) )
{
DHCP_DEBUG("Wrong DHCP ID, discarded\r\n");
return;
}
dhcp_parse_options(&msg->options[0], &cache, (htons(ip->IP_Pktlen)-264) );
// check if file field or sname field are overloaded (option 52)
switch (cache.ovld)
{
case 0: // no overload, do nothing
break;
case 1: // the file field contains options
dhcp_parse_options(&msg->file[0], &cache, 128);
break;
case 2: // the sname field contains options
dhcp_parse_options(&msg->sname[0], &cache, 64);
break;
case 3: // the file and the sname field contain options
dhcp_parse_options(&msg->file[0], &cache, 128);
dhcp_parse_options(&msg->sname[0], &cache, 64);
break;
default: // must not occur
DHCP_DEBUG("Option 52 Error\r\n");
break;
}
switch (cache.type)
{
case DHCPOFFER:
// this will be our IP address
(*((unsigned long*)&myip[0])) = (*((unsigned long*)&msg->yiaddr[0]));
DHCP_DEBUG("** DHCP OFFER RECVD! **\r\n");
dhcp_state = DHCP_STATE_OFFER_RCVD;
break;
case DHCPACK:
DHCP_DEBUG("** DHCP ACK RECVD! **\r\n");
dhcp_state = DHCP_STATE_ACK_RCVD;
break;
case DHCPNAK:
DHCP_DEBUG("** DHCP NAK RECVD! **\r\n");
dhcp_state = DHCP_STATE_NAK_RCVD;
break;
}
}
//----------------------------------------------------------------------------
//read all the options
//pointer to the variables and size from options to packet end
void dhcp_parse_options (unsigned char *msg, struct dhcp_cache *c, unsigned int size)
{
unsigned int ix;
ix = 0;
do
{
switch (msg[ix])
{
case 0: //Padding
ix++;
break;
case 1: //Netmask
ix++;
if ( msg[ix] == 4 )
{
ix++;
get4bytes(&msg[ix], &c->netmask[0]);
ix += 4;
}
else
{
ix += (msg[ix]+1);
}
break;
case 3: //router (gateway IP)
ix++;
if ( msg[ix] == 4 )
{
ix++;
get4bytes(&msg[ix], &c->router_ip[0]);
ix += 4;
}
else
{
ix += (msg[ix]+1);
}
break;
case 6: //dns len = n * 4
ix++;
if ( msg[ix] == 4 )
{
ix++;
get4bytes(&msg[ix], &c->dns1_ip[0]);
ix += 4;
}
else
if ( msg[ix] == 8 )
{
ix++;
get4bytes(&msg[ix], &c->dns1_ip[0]);
ix += 4;
get4bytes(&msg[ix], &c->dns2_ip[0]);
ix += 4;
}
else
{
ix += (msg[ix]+1);
}
break;
case 51: //lease time
ix++;
if ( msg[ix] == 4 )
{
ix++;
get4bytes(&msg[ix], &c->lease[0]);
ix += 4;
}
else
{
ix += msg[ix]+1;
}
break;
case 52: //Options overload
ix++;
if ( msg[ix] == 1 ) //size == 1
{
ix++;
c->ovld = msg[ix];
ix++;
}
else
{
ix += (msg[ix]+1);
}
break;
case 53: //DHCP Type
ix++;
if ( msg[ix] == 1 ) //size == 1
{
ix++;
c->type = msg[ix];
ix++;
}
else
{
ix += (msg[ix]+1);
}
break;
case 54: //Server identifier
ix++;
if ( msg[ix] == 4 )
{
ix++;
get4bytes(&msg[ix], &c->serv_id[0]);
ix += 4;
}
else
{
ix += msg[ix]+1;
}
break;
case 99: //Magic cookie
ix += 4;
break;
case 0xff: //end option
break;
default:
DHCP_DEBUG("Unknown Option: %2x\r\n", msg[ix]);
ix++;
ix += (msg[ix]+1);
break;
}
}
while ( (msg[ix] != 0xff) && (ix < size) );
}
//----------------------------------------------------------------------------
//Sendet DHCP messages an Broadcast
void dhcp_message (unsigned char type)
{
struct dhcp_msg *msg;
unsigned char *options;
for (unsigned int i=0; i < sizeof (struct dhcp_msg); i++) //clear eth_buffer to 0
{
eth_buffer[UDP_DATA_START+i] = 0;
}
msg = (struct dhcp_msg *)ð_buffer[UDP_DATA_START];
msg->op = 1; // BOOTREQUEST
msg->htype = 1; // Ethernet
msg->hlen = 6; // Ethernet MAC
msg->xid[0] = MYMAC6; //use the MAC as the ID to be unique in the LAN
msg->xid[1] = MYMAC5;
msg->xid[2] = MYMAC4;
msg->xid[3] = MYMAC3;
msg->flags = HTONS(0x8000);
msg->chaddr[0] = MYMAC1;
msg->chaddr[1] = MYMAC2;
msg->chaddr[2] = MYMAC3;
msg->chaddr[3] = MYMAC4;
msg->chaddr[4] = MYMAC5;
msg->chaddr[5] = MYMAC6;
options = &msg->options[0]; //options
*options++ = 99; //magic cookie
*options++ = 130;
*options++ = 83;
*options++ = 99;
*options++ = 53; // Option 53: DHCP message type DHCP Discover
*options++ = 1; // len = 1
*options++ = type; // 1 = DHCP Discover
*options++ = 55; // Option 55: parameter request list
*options++ = 3; // len = 3
*options++ = 1; // netmask
*options++ = 3; // router
*options++ = 6; // dns
*options++ = 50; // Option 54: requested IP
*options++ = 4; // len = 4
*options++ = myip[0];
*options++ = myip[1];
*options++ = myip[2];
*options++ = myip[3];
switch (type)
{
case DHCPDISCOVER:
dhcp_state = DHCP_STATE_DISCOVER_SENT;
DHCP_DEBUG("DISCOVER sent\r\n");
break;
case DHCPREQUEST:
*options++ = 54; // Option 54: server ID
*options++ = 4; // len = 4
*options++ = cache.serv_id[0];
*options++ = cache.serv_id[1];
*options++ = cache.serv_id[2];
*options++ = cache.serv_id[3];
dhcp_state = DHCP_STATE_REQUEST_SENT;
DHCP_DEBUG("REQUEST sent\r\n");
break;
default:
DHCP_DEBUG("Wrong DHCP msg type\r\n");
break;
}
*options++ = 12; // Option 12: host name
*options++ = 8; // len = 8
*options++ = 'M';
*options++ = 'i';
*options++ = 'n';
*options++ = 'i';
*options++ = '-';
*options++ = 'A';
*options++ = 'V';
*options++ = 'R';
*options = 0xff; //end option
create_new_udp_packet(sizeof (struct dhcp_msg),DHCP_CLIENT_PORT,DHCP_SERVER_PORT,(unsigned long)0xffffffff);
}
