struct LL_IP *DHCP_IPAllocate(int nDhcpType, struct in_addr *pPreviousAddr, const unsigned char *pMac, int nMacLen)
{
int Rc=1;
struct LL_IP *pCurIP;
ULONG dummy_mac[2];
int dummy_maclen = sizeof dummy_mac;
do
{
pCurIP = DHCP_IPAllocate2 (pPreviousAddr, pMac, nMacLen);
// 2010/09/27 Colin from Shangai points out that ICMP check should be done only for DISCOVER
if (pCurIP!=NULL && sSettings.bPing && nDhcpType==DHCPDISCOVER)
{
// frees the ARP cache and send an ARP request
ArpDeleteHost (pCurIP->dwIP);
SendARP(pCurIP->dwIP.s_addr, 0, dummy_mac, &dummy_maclen);
Rc = PingApi (&pCurIP->dwIP, DHCP_PINGTIMEOUT, NULL)==PINGAPI_TIMEOUT
&& PingApi (&pCurIP->dwIP, DHCP_PINGTIMEOUT, NULL)==PINGAPI_TIMEOUT
&& PingApi (&pCurIP->dwIP, DHCP_PINGTIMEOUT, NULL)==PINGAPI_TIMEOUT ;
if (!Rc)
{
LOG (2, "Suppress pingable address %s", inet_ntoa (pCurIP->dwIP));
DHCPReallocItem (pCurIP, pCurIP->dwIP.s_addr, FREE_DHCP_ADDRESS, 6);
SetRenewTime (pCurIP);
}
} // bPing Settings
}
while (pCurIP!=NULL && !Rc);
return pCurIP;
}
// Search in configuration file/registry by Mac Address
struct LL_IP *DHCPSearchByRegistry (const unsigned char *pMac, int nMacLen)
{
int Rc;
HKEY hKey;
char szIP[20];
DWORD dwSize;
if (nMacLen!=6) return NULL; // work only for Ethernet and Token Ring
szIP[0] = 0;
Rc = RegOpenKeyEx (HKEY_LOCAL_MACHINE, // Key handle at root level.
TFTPD32_DHCP_KEY, // Path name of child key.
0, // Reserved.
KEY_READ, // Requesting read access.
& hKey) == ERROR_SUCCESS; // Address of key to be returned.
if (Rc) READKEY (haddrtoa(pMac, nMacLen), szIP);
CloseHandle (hKey);
if (isdigit (szIP[0])) // entry has been found
return DHCPReallocItem (NULL, inet_addr (szIP), pMac, nMacLen);
return NULL;
} // DHCPSearchByRegistry
struct LL_IP *DHCP_IPAllocate2(struct in_addr *pPreviousAddr, const unsigned char *pMac, int nMacLen)
{
time_t tNow;
int Ark;
struct LL_IP *pCurIP /*, *pOldestIP*/;
#define TWO_MINUTES 120
//If true, the client has requested an IP address that we should try to honor
int useprev = (pPreviousAddr->s_addr != INADDR_ANY) && (AddrFitsPool(pPreviousAddr));
// search for the previously allocated mac address
if (nMacLen>=6) // Ethernet Mac address
{
// search if mac the mac address is already known
pCurIP = DHCPSearchByMacAddress (pMac, nMacLen);
if(pCurIP)
{
//We found the previous MAC record. If the address requested is invalid, use
//the address in the record. If it is valid, erase the record, since we should
//give the requested address
if(!useprev || (pPreviousAddr->s_addr == pCurIP->dwIP.s_addr))
{
LOG (12, "Reply with previously allocated : %s", inet_ntoa (pCurIP->dwIP));
SetAllocTime(pCurIP);
return pCurIP;
}
else //Remove the old address, and continue with the allocation logic
{
//Destroying the item takes care of the macaddr table as well.
DHCPDestroyItem (pCurIP);
pCurIP = NULL;
}
} // mac address found
} // mac address not valid
// search if requested address can be granted
if(useprev)
{
// is the address already allocated but not renewed (or expired)
BOOL wasexpired=FALSE;
pCurIP = DHCPSearchByIP (pPreviousAddr, &wasexpired);
if (pCurIP!=NULL)
{
//Only allocate if it's to the same address, or the lease expired,
//otherwise reset for the real allocation
if(wasexpired || (0 == memcmp(pCurIP->sMacAddr, pMac, nMacLen)))
{
LOG (5, "Request for %s granted", inet_ntoa (pCurIP->dwIP));
pCurIP = DHCPReallocItem (pCurIP, pPreviousAddr->s_addr, pMac, nMacLen);
return pCurIP ;
}
else
pCurIP = NULL;
}
else //Address not allocated before, just grant it
{
pCurIP = DHCPReallocItem (NULL, pPreviousAddr->s_addr, pMac, nMacLen);
LOG (12, "Reply with requested address : %s", inet_ntoa (pCurIP->dwIP));
return pCurIP;
} //
} // Requested address asked
// A new IP address should be allocated :
// First check if the pool is large enough in order to allocate a new address
if (sParamDHCP.nPoolSize>0 && nAllocatedIP < sParamDHCP.nPoolSize)
{
// search for an "hole" in the struct or take last elem + 1
// if an item was allocated and the first item is the first in pool
//Don't allocate ip addresses ending in 0 or 255
if (nAllocatedIP>0 && tFirstIP[0]->dwIP.s_addr == sParamDHCP.dwAddr.s_addr)
{
for ( Ark=1 ;
Ark<nAllocatedIP
&& ntohl (tFirstIP[Ark]->dwIP.s_addr) == AddrInc(tFirstIP[Ark-1]->dwIP);
Ark ++ );
pCurIP = DHCPReallocItem (NULL, htonl (AddrInc(tFirstIP[Ark-1]->dwIP)), pMac, nMacLen);
}
else pCurIP = DHCPReallocItem (NULL, sParamDHCP.dwAddr.s_addr, pMac, nMacLen);
// New address : ntohl (tFirstIP[Ark]->dwIP.s_addr) + 1
// it is OK if Ark has reach nAllocatedIP
LOG (12, "Reply with new : %s", inet_ntoa (pCurIP->dwIP));
return pCurIP;
} // new allocation
// no free address, have to reuse an "old" one
// try addresses which have not been acknowledged (tAllocated+2 minutes),
// or that have expired
//
time (&tNow);
for (Ark=0 ; Ark<nAllocatedIP; Ark++)
{
pCurIP = tFirstIP[Ark];
if ( pCurIP->tAllocated+TWO_MINUTES < tNow
&& ((pCurIP->tRenewed==0) || (tNow > pCurIP->tRenewed + (sParamDHCP.nLease * 60))))
{
pCurIP = DHCPReallocItem (pCurIP, pCurIP->dwIP.s_addr, pMac, nMacLen);
LOG (12, "Reply with reuse : %s", inet_ntoa (pCurIP->dwIP));
return pCurIP;
}
} // reuse an unacknowledged address
/* Since we are replacing holes, unacked, and expired addresses, all addresses are currently used
// search for the oldest one (use tAllocated and tRenewed)
for (Ark=0, pOldestIP=NULL ; Ark<nAllocatedIP; Ark++)
{
pCurIP = tFirstIP[Ark];
if ( pCurIP->tRenewed!=0
&& pCurIP->tRenewed < (unsigned) (pOldestIP==NULL ? 0xFFFFFFFF : pOldestIP->tRenewed )
&& PingApi (&pCurIP->dwIP, DHCP_PINGTIMEOUT, NULL)==PINGAPI_TIMEOUT
&& PingApi (&pCurIP->dwIP, DHCP_PINGTIMEOUT, NULL)==PINGAPI_TIMEOUT
&& PingApi (&pCurIP->dwIP, DHCP_PINGTIMEOUT, NULL)==PINGAPI_TIMEOUT
) pOldestIP=pCurIP;
} // search for oldest item in pOldestIP
if (pOldestIP != NULL)
{
pCurIP = DHCPReallocItem (pOldestIP, pOldestIP->dwIP.s_addr, pMac, nMacLen);
LOG (12, "Reply with reuse : %s", inet_ntoa (pCurIP->dwIP));
return pCurIP; // can be NULL
}
*/
return NULL;
} // DHCP_IPAllocate2
