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Arduino/libraries/Ethernet/src/Dhcp.cpp

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// DHCP Library v0.3 - April 25, 2009
// Author: Jordan Terrell - blog.jordanterrell.com
#include "utility/w5100.h"
#include <string.h>
#include <stdlib.h>
#include "Dhcp.h"
#include "Arduino.h"
#include "utility/util.h"
int DhcpClass::beginWithDHCP(uint8_t *mac, unsigned long timeout, unsigned long responseTimeout)
{
_dhcpLeaseTime=0;
_dhcpT1=0;
_dhcpT2=0;
_lastCheck=0;
_timeout = timeout;
_responseTimeout = responseTimeout;
// zero out _dhcpMacAddr
memset(_dhcpMacAddr, 0, 6);
reset_DHCP_lease();
memcpy((void*)_dhcpMacAddr, (void*)mac, 6);
_dhcp_state = STATE_DHCP_START;
return request_DHCP_lease();
}
void DhcpClass::reset_DHCP_lease(){
// zero out _dhcpSubnetMask, _dhcpGatewayIp, _dhcpLocalIp, _dhcpDhcpServerIp, _dhcpDnsServerIp
memset(_dhcpLocalIp, 0, 20);
}
//return:0 on error, 1 if request is sent and response is received
int DhcpClass::request_DHCP_lease(){
uint8_t messageType = 0;
// Pick an initial transaction ID
_dhcpTransactionId = random(1UL, 2000UL);
_dhcpInitialTransactionId = _dhcpTransactionId;
_dhcpUdpSocket.stop();
if (_dhcpUdpSocket.begin(DHCP_CLIENT_PORT) == 0)
{
// Couldn't get a socket
return 0;
}
presend_DHCP();
int result = 0;
unsigned long startTime = millis();
while(_dhcp_state != STATE_DHCP_LEASED)
{
if(_dhcp_state == STATE_DHCP_START)
{
_dhcpTransactionId++;
send_DHCP_MESSAGE(DHCP_DISCOVER, ((millis() - startTime) / 1000));
_dhcp_state = STATE_DHCP_DISCOVER;
}
else if(_dhcp_state == STATE_DHCP_REREQUEST){
_dhcpTransactionId++;
send_DHCP_MESSAGE(DHCP_REQUEST, ((millis() - startTime)/1000));
_dhcp_state = STATE_DHCP_REQUEST;
}
else if(_dhcp_state == STATE_DHCP_DISCOVER)
{
uint32_t respId;
messageType = parseDHCPResponse(_responseTimeout, respId);
if(messageType == DHCP_OFFER)
{
// We'll use the transaction ID that the offer came with,
// rather than the one we were up to
_dhcpTransactionId = respId;
send_DHCP_MESSAGE(DHCP_REQUEST, ((millis() - startTime) / 1000));
_dhcp_state = STATE_DHCP_REQUEST;
}
}
else if(_dhcp_state == STATE_DHCP_REQUEST)
{
uint32_t respId;
messageType = parseDHCPResponse(_responseTimeout, respId);
if(messageType == DHCP_ACK)
{
_dhcp_state = STATE_DHCP_LEASED;
result = 1;
//use default lease time if we didn't get it
if(_dhcpLeaseTime == 0){
_dhcpLeaseTime = DEFAULT_LEASE;
}
//calculate T1 & T2 if we didn't get it
if(_dhcpT1 == 0){
//T1 should be 50% of _dhcpLeaseTime
_dhcpT1 = _dhcpLeaseTime >> 1;
}
if(_dhcpT2 == 0){
//T2 should be 87.5% (7/8ths) of _dhcpLeaseTime
_dhcpT2 = _dhcpT1 << 1;
}
_renewInSec = _dhcpT1;
_rebindInSec = _dhcpT2;
}
else if(messageType == DHCP_NAK)
_dhcp_state = STATE_DHCP_START;
}
if(messageType == 255)
{
messageType = 0;
_dhcp_state = STATE_DHCP_START;
}
if(result != 1 && ((millis() - startTime) > _timeout))
break;
}
// We're done with the socket now
_dhcpUdpSocket.stop();
_dhcpTransactionId++;
return result;
}
void DhcpClass::presend_DHCP()
{
}
void DhcpClass::send_DHCP_MESSAGE(uint8_t messageType, uint16_t secondsElapsed)
{
uint8_t buffer[32];
memset(buffer, 0, 32);
IPAddress dest_addr( 255, 255, 255, 255 ); // Broadcast address
if (-1 == _dhcpUdpSocket.beginPacket(dest_addr, DHCP_SERVER_PORT))
{
// FIXME Need to return errors
return;
}
buffer[0] = DHCP_BOOTREQUEST; // op
buffer[1] = DHCP_HTYPE10MB; // htype
buffer[2] = DHCP_HLENETHERNET; // hlen
buffer[3] = DHCP_HOPS; // hops
// xid
unsigned long xid = htonl(_dhcpTransactionId);
memcpy(buffer + 4, &(xid), 4);
// 8, 9 - seconds elapsed
buffer[8] = ((secondsElapsed & 0xff00) >> 8);
buffer[9] = (secondsElapsed & 0x00ff);
// flags
unsigned short flags = htons(DHCP_FLAGSBROADCAST);
memcpy(buffer + 10, &(flags), 2);
// ciaddr: already zeroed
// yiaddr: already zeroed
// siaddr: already zeroed
// giaddr: already zeroed
//put data in W5100 transmit buffer
_dhcpUdpSocket.write(buffer, 28);
memset(buffer, 0, 32); // clear local buffer
memcpy(buffer, _dhcpMacAddr, 6); // chaddr
//put data in W5100 transmit buffer
_dhcpUdpSocket.write(buffer, 16);
memset(buffer, 0, 32); // clear local buffer
// leave zeroed out for sname && file
// put in W5100 transmit buffer x 6 (192 bytes)
for(int i = 0; i < 6; i++) {
_dhcpUdpSocket.write(buffer, 32);
}
// OPT - Magic Cookie
buffer[0] = (uint8_t)((MAGIC_COOKIE >> 24)& 0xFF);
buffer[1] = (uint8_t)((MAGIC_COOKIE >> 16)& 0xFF);
buffer[2] = (uint8_t)((MAGIC_COOKIE >> 8)& 0xFF);
buffer[3] = (uint8_t)(MAGIC_COOKIE& 0xFF);
// OPT - message type
buffer[4] = dhcpMessageType;
buffer[5] = 0x01;
buffer[6] = messageType; //DHCP_REQUEST;
// OPT - client identifier
buffer[7] = dhcpClientIdentifier;
buffer[8] = 0x07;
buffer[9] = 0x01;
memcpy(buffer + 10, _dhcpMacAddr, 6);
// OPT - host name
buffer[16] = hostName;
buffer[17] = strlen(HOST_NAME) + 6; // length of hostname + last 3 bytes of mac address
strcpy((char*)&(buffer[18]), HOST_NAME);
printByte((char*)&(buffer[24]), _dhcpMacAddr[3]);
printByte((char*)&(buffer[26]), _dhcpMacAddr[4]);
printByte((char*)&(buffer[28]), _dhcpMacAddr[5]);
//put data in W5100 transmit buffer
_dhcpUdpSocket.write(buffer, 30);
if(messageType == DHCP_REQUEST)
{
buffer[0] = dhcpRequestedIPaddr;
buffer[1] = 0x04;
buffer[2] = _dhcpLocalIp[0];
buffer[3] = _dhcpLocalIp[1];
buffer[4] = _dhcpLocalIp[2];
buffer[5] = _dhcpLocalIp[3];
buffer[6] = dhcpServerIdentifier;
buffer[7] = 0x04;
buffer[8] = _dhcpDhcpServerIp[0];
buffer[9] = _dhcpDhcpServerIp[1];
buffer[10] = _dhcpDhcpServerIp[2];
buffer[11] = _dhcpDhcpServerIp[3];
//put data in W5100 transmit buffer
_dhcpUdpSocket.write(buffer, 12);
}
buffer[0] = dhcpParamRequest;
buffer[1] = 0x06;
buffer[2] = subnetMask;
buffer[3] = routersOnSubnet;
buffer[4] = dns;
buffer[5] = domainName;
buffer[6] = dhcpT1value;
buffer[7] = dhcpT2value;
buffer[8] = endOption;
//put data in W5100 transmit buffer
_dhcpUdpSocket.write(buffer, 9);
_dhcpUdpSocket.endPacket();
}
uint8_t DhcpClass::parseDHCPResponse(unsigned long responseTimeout, uint32_t& transactionId)
{
uint8_t type = 0;
uint8_t opt_len = 0;
unsigned long startTime = millis();
while(_dhcpUdpSocket.parsePacket() <= 0)
{
if((millis() - startTime) > responseTimeout)
{
return 255;
}
delay(50);
}
// start reading in the packet
RIP_MSG_FIXED fixedMsg;
_dhcpUdpSocket.read((uint8_t*)&fixedMsg, sizeof(RIP_MSG_FIXED));
if(fixedMsg.op == DHCP_BOOTREPLY && _dhcpUdpSocket.remotePort() == DHCP_SERVER_PORT)
{
transactionId = ntohl(fixedMsg.xid);
if(memcmp(fixedMsg.chaddr, _dhcpMacAddr, 6) != 0 || (transactionId < _dhcpInitialTransactionId) || (transactionId > _dhcpTransactionId))
{
// Need to read the rest of the packet here regardless
_dhcpUdpSocket.flush();
return 0;
}
memcpy(_dhcpLocalIp, fixedMsg.yiaddr, 4);
// Skip to the option part
// Doing this a byte at a time so we don't have to put a big buffer
// on the stack (as we don't have lots of memory lying around)
for (int i =0; i < (240 - (int)sizeof(RIP_MSG_FIXED)); i++)
{
_dhcpUdpSocket.read(); // we don't care about the returned byte
}
while (_dhcpUdpSocket.available() > 0)
{
switch (_dhcpUdpSocket.read())
{
case endOption :
break;
case padOption :
break;
case dhcpMessageType :
opt_len = _dhcpUdpSocket.read();
type = _dhcpUdpSocket.read();
break;
case subnetMask :
opt_len = _dhcpUdpSocket.read();
_dhcpUdpSocket.read(_dhcpSubnetMask, 4);
break;
case routersOnSubnet :
opt_len = _dhcpUdpSocket.read();
_dhcpUdpSocket.read(_dhcpGatewayIp, 4);
for (int i = 0; i < opt_len-4; i++)
{
_dhcpUdpSocket.read();
}
break;
case dns :
opt_len = _dhcpUdpSocket.read();
_dhcpUdpSocket.read(_dhcpDnsServerIp, 4);
for (int i = 0; i < opt_len-4; i++)
{
_dhcpUdpSocket.read();
}
break;
case dhcpServerIdentifier :
opt_len = _dhcpUdpSocket.read();
if( *((uint32_t*)_dhcpDhcpServerIp) == 0 ||
IPAddress(_dhcpDhcpServerIp) == _dhcpUdpSocket.remoteIP() )
{
_dhcpUdpSocket.read(_dhcpDhcpServerIp, sizeof(_dhcpDhcpServerIp));
}
else
{
// Skip over the rest of this option
while (opt_len--)
{
_dhcpUdpSocket.read();
}
}
break;
case dhcpT1value :
opt_len = _dhcpUdpSocket.read();
_dhcpUdpSocket.read((uint8_t*)&_dhcpT1, sizeof(_dhcpT1));
_dhcpT1 = ntohl(_dhcpT1);
break;
case dhcpT2value :
opt_len = _dhcpUdpSocket.read();
_dhcpUdpSocket.read((uint8_t*)&_dhcpT2, sizeof(_dhcpT2));
_dhcpT2 = ntohl(_dhcpT2);
break;
case dhcpIPaddrLeaseTime :
opt_len = _dhcpUdpSocket.read();
_dhcpUdpSocket.read((uint8_t*)&_dhcpLeaseTime, sizeof(_dhcpLeaseTime));
_dhcpLeaseTime = ntohl(_dhcpLeaseTime);
_renewInSec = _dhcpLeaseTime;
break;
default :
opt_len = _dhcpUdpSocket.read();
// Skip over the rest of this option
while (opt_len--)
{
_dhcpUdpSocket.read();
}
break;
}
}
}
// Need to skip to end of the packet regardless here
_dhcpUdpSocket.flush();
return type;
}
/*
returns:
0/DHCP_CHECK_NONE: nothing happened
1/DHCP_CHECK_RENEW_FAIL: renew failed
2/DHCP_CHECK_RENEW_OK: renew success
3/DHCP_CHECK_REBIND_FAIL: rebind fail
4/DHCP_CHECK_REBIND_OK: rebind success
*/
int DhcpClass::checkLease(){
//this uses a signed / unsigned trick to deal with millis overflow
unsigned long now = millis();
signed long snow = (long)now;
int rc=DHCP_CHECK_NONE;
if (_lastCheck != 0){
signed long factor;
//calc how many ms past the timeout we are
factor = snow - (long)_secTimeout;
//if on or passed the timeout, reduce the counters
if ( factor >= 0 ){
//next timeout should be now plus 1000 ms minus parts of second in factor
_secTimeout = snow + 1000 - factor % 1000;
//how many seconds late are we, minimum 1
factor = factor / 1000 +1;
//reduce the counters by that mouch
//if we can assume that the cycle time (factor) is fairly constant
//and if the remainder is less than cycle time * 2
//do it early instead of late
if(_renewInSec < factor*2 )
_renewInSec = 0;
else
_renewInSec -= factor;
if(_rebindInSec < factor*2 )
_rebindInSec = 0;
else
_rebindInSec -= factor;
}
//if we have a lease but should renew, do it
if (_dhcp_state == STATE_DHCP_LEASED && _renewInSec <=0){
_dhcp_state = STATE_DHCP_REREQUEST;
rc = 1 + request_DHCP_lease();
}
//if we have a lease or is renewing but should bind, do it
if( (_dhcp_state == STATE_DHCP_LEASED || _dhcp_state == STATE_DHCP_START) && _rebindInSec <=0){
//this should basically restart completely
_dhcp_state = STATE_DHCP_START;
reset_DHCP_lease();
rc = 3 + request_DHCP_lease();
}
}
else{
_secTimeout = snow + 1000;
}
_lastCheck = now;
return rc;
}
IPAddress DhcpClass::getLocalIp()
{
return IPAddress(_dhcpLocalIp);
}
IPAddress DhcpClass::getSubnetMask()
{
return IPAddress(_dhcpSubnetMask);
}
IPAddress DhcpClass::getGatewayIp()
{
return IPAddress(_dhcpGatewayIp);
}
IPAddress DhcpClass::getDhcpServerIp()
{
return IPAddress(_dhcpDhcpServerIp);
}
IPAddress DhcpClass::getDnsServerIp()
{
return IPAddress(_dhcpDnsServerIp);
}
void DhcpClass::printByte(char * buf, uint8_t n ) {
char *str = &buf[1];
buf[0]='0';
do {
unsigned long m = n;
n /= 16;
char c = m - 16 * n;
*str-- = c < 10 ? c + '0' : c + 'A' - 10;
} while(n);
}