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Cedar: DHCP server now assigns static IPv4 address, if present in user note

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This works for all VPN protocols.

In SessionMain(): for DHCPDISCOVER and DHCPREQUEST frames, write the static IP address (which is retrieved from the user notes) in the SIADDR field of DHCPHEADER.

In VirtualDhcpServer(): for DHCPDISCOVER and DHCPREQUEST frames, read the static IP address from the SIADDR field of DHCPHEADER and assign it to the client.
This commit is contained in:
PeTeeR
2020-10-12 04:56:30 +02:00
committed by Davide Beatrici
parent 1c4b257a1b
commit b890c7d813
6 changed files with 240 additions and 10 deletions
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52
src/Cedar/Virtual.c
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@ -9198,6 +9198,11 @@ PENDING_LIST_CLEANUP:
// Correspond to the DHCP REQUEST
UINT ServeDhcpRequest(VH *v, UCHAR *mac, UINT request_ip)
{
return ServeDhcpRequestEx(v, mac, request_ip, false);
}
UINT ServeDhcpRequestEx(VH *v, UCHAR *mac, UINT request_ip, bool is_static_ip)
{
UINT ret;
// Validate arguments
@ -9206,7 +9211,7 @@ UINT ServeDhcpRequest(VH *v, UCHAR *mac, UINT request_ip)
return 0;
}
ret = ServeDhcpDiscover(v, mac, request_ip);
ret = ServeDhcpDiscoverEx(v, mac, request_ip, is_static_ip);
if (ret != request_ip)
{
if (request_ip != 0)
@ -9309,6 +9314,34 @@ UINT ServeDhcpDiscover(VH *v, UCHAR *mac, UINT request_ip)
return ret;
}
UINT ServeDhcpDiscoverEx(VH *v, UCHAR *mac, UINT request_ip, bool is_static_ip)
{
if (is_static_ip == false)
{
return ServeDhcpDiscover(v, mac, request_ip );
}
if (v == NULL || mac == NULL || request_ip == 0)
{
return 0;
}
DHCP_LEASE *d = SearchDhcpLeaseByIp(v, request_ip);
if (d != NULL)
{
// The requested IP address is used already
return 0;
}
// For static IP, the requested IP address must NOT be within the range of the DHCP pool
if (Endian32(request_ip) < Endian32(v->DhcpIpStart) || Endian32(request_ip) > Endian32(v->DhcpIpEnd))
{
return request_ip;
}
return 0;
}
// Take an appropriate IP addresses that can be assigned newly
UINT GetFreeDhcpIpAddress(VH *v)
{
@ -9469,21 +9502,30 @@ void VirtualDhcpServer(VH *v, PKT *p)
if (dhcp->OpCode == 1 && (opt->Opcode == DHCP_DISCOVER || opt->Opcode == DHCP_REQUEST || opt->Opcode == DHCP_INFORM))
{
// Operate as the server
UINT ip = 0;
UINT ip = 0, ip_static = dhcp->ServerIP;
dhcp->ServerIP = 0;
if (opt->RequestedIp == 0)
{
opt->RequestedIp = p->L3.IPv4Header->SrcIP;
opt->RequestedIp = (ip_static ? ip_static : p->L3.IPv4Header->SrcIP);
}
if (opt->Opcode == DHCP_DISCOVER)
{
// Return an IP address that can be used
ip = ServeDhcpDiscover(v, p->MacAddressSrc, opt->RequestedIp);
ip = ServeDhcpDiscoverEx(v, p->MacAddressSrc, opt->RequestedIp, ip_static);
}
else if (opt->Opcode == DHCP_REQUEST)
{
// Determine the IP address
ip = ServeDhcpRequest(v, p->MacAddressSrc, opt->RequestedIp);
if (ip_static && opt->RequestedIp != ip_static)
{
// Don't allow opt->RequestedIp other than the IP written in user's note
ip = 0;
}
else
{
ip = ServeDhcpRequestEx(v, p->MacAddressSrc, opt->RequestedIp, ip_static);
}
}
if (ip != 0 || opt->Opcode == DHCP_INFORM)