56 lines
1.9 KiB
C
56 lines
1.9 KiB
C
/* Benjamin DELPY `gentilkiwi`
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http://blog.gentilkiwi.com
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benjamin@gentilkiwi.com
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Licence : https://creativecommons.org/licenses/by/4.0/
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*/
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#include "kdhcp.h"
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HMODULE kdhcp_nextLibrary = NULL;
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LPDHCP_NEWPKT kdhcp_nextLibraryCalloutNewPkt = NULL;
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BOOL APIENTRY DllMain(HMODULE hModule, DWORD ul_reason_for_call, LPVOID lpReserved)
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{
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if((ul_reason_for_call == DLL_PROCESS_DETACH) && kdhcp_nextLibrary)
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FreeLibrary(kdhcp_nextLibrary);
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return TRUE;
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}
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DWORD CALLBACK kdhcp_DhcpServerCalloutEntry(IN LPWSTR ChainDlls, IN DWORD CalloutVersion, IN OUT LPDHCP_CALLOUT_TABLE CalloutTbl)
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{
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LPDHCP_ENTRY_POINT_FUNC nextEntry;
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RtlZeroMemory(CalloutTbl, sizeof(DHCP_CALLOUT_TABLE));
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if(ChainDlls)
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if(kdhcp_nextLibrary = LoadLibrary(ChainDlls))
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if(nextEntry = (LPDHCP_ENTRY_POINT_FUNC) GetProcAddress(kdhcp_nextLibrary, DHCP_CALLOUT_ENTRY_POINT))
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nextEntry(ChainDlls + lstrlenW(ChainDlls) + 1, CalloutVersion, CalloutTbl);
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if(CalloutTbl->DhcpNewPktHook)
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kdhcp_nextLibraryCalloutNewPkt = CalloutTbl->DhcpNewPktHook;
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CalloutTbl->DhcpNewPktHook = kdhcp_DhcpNewPktHook;
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return ERROR_SUCCESS;
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}
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const BYTE macToBlack[][MAC_ADDRESS_SIZE] = {
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{0x00, 0x0c, 0x29, 0x00, 0x00, 0x00},
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{0x00, 0x50, 0x56, 0x00, 0x00, 0x00}
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};
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DWORD CALLBACK kdhcp_DhcpNewPktHook(IN OUT LPBYTE *Packet, IN OUT DWORD *PacketSize, IN DWORD IpAddress, IN LPVOID Reserved, IN OUT LPVOID *PktContext, OUT LPBOOL ProcessIt)
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{
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DWORD status = ERROR_SUCCESS, m;
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*ProcessIt = TRUE;
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for(m = 0; m < ARRAYSIZE(macToBlack); m++)
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{
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if(RtlEqualMemory(*Packet + MAC_SOURCE_ADDRESS_OFFSET, macToBlack[m], MAC_ADDRESS_SIZE / 2)) // just the start of the address
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{
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*ProcessIt = FALSE;
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status = DHCP_DROP_INVALID;
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break;
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}
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}
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if(kdhcp_nextLibraryCalloutNewPkt && *ProcessIt)
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status = kdhcp_nextLibraryCalloutNewPkt(Packet, PacketSize, IpAddress, Reserved, PktContext, ProcessIt);
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return status;
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} |