有人愿意分享一些关于如何使用 LSP 进行数据包修改的见解吗?
我正在使用非 IFS 子类型,我可以看到(伪?)数据包如何首先进入 WSPRecv。但是我该如何修改它们呢?我的查询是关于一个导致 WSPRecv 被调用 3 次的 HTTP 响应 :((。我需要修改这个响应的几个部分,但由于它分为 3 个部分,因此很难相应地修改它。而且,也许在其他机器上或在不同条件下(例如高流量)只有一个 WSPRecv 调用,或者可能有 10 个调用。解决此问题的最佳方法是什么(请不要 NDIS :D),以及如何正确更改通过增加缓冲区(lpBuffers->buf)?
int WSPAPI
WSPRecv(
SOCKET s,
LPWSABUF lpBuffers,
DWORD dwBufferCount,
LPDWORD lpNumberOfBytesRecvd,
LPDWORD lpFlags,
LPWSAOVERLAPPED lpOverlapped,
LPWSAOVERLAPPED_COMPLETION_ROUTINE lpCompletionRoutine,
LPWSATHREADID lpThreadId,
LPINT lpErrno
)
{
LPWSAOVERLAPPEDPLUS ProviderOverlapped = NULL;
SOCK_INFO *SocketContext = NULL;
int ret = SOCKET_ERROR;
*lpErrno = NO_ERROR;
//
// Find our provider socket corresponding to this one
//
SocketContext = FindAndRefSocketContext(s, lpErrno);
if ( NULL == SocketContext )
{
dbgprint( "WSPRecv: FindAndRefSocketContext failed!" );
goto cleanup;
}
//
// Check for overlapped I/O
//
if ( NULL != lpOverlapped )
{
/*bla bla .. not interesting in my case*/
}
else
{
ASSERT( SocketContext->Provider->NextProcTable.lpWSPRecv );
SetBlockingProvider(SocketContext->Provider);
ret = SocketContext->Provider->NextProcTable.lpWSPRecv(
SocketContext->ProviderSocket,
lpBuffers,
dwBufferCount,
lpNumberOfBytesRecvd,
lpFlags,
lpOverlapped,
lpCompletionRoutine,
lpThreadId,
lpErrno);
SetBlockingProvider(NULL);
//is this the place to modify packet length and contents ?
if (strstr(lpBuffers->buf, "var mapObj = null;"))
{
int nLen = strlen(lpBuffers->buf) + 200;
/*CHAR *szNewBuf = new CHAR[];
CHAR *pIndex;
pIndex = strstr(lpBuffers->buf, "var mapObj = null;");
nLen = strlen(strncpy(szNewBuf, lpBuffers->buf, (pIndex - lpBuffers->buf) * sizeof (CHAR)));
nLen = strlen(strncpy(szNewBuf + nLen * sizeof(CHAR), "var com = null;\r\n", 17 * sizeof(CHAR)));
pIndex += 18 * sizeof(CHAR);
nLen = strlen(strncpy(szNewBuf + nLen * sizeof(CHAR), pIndex, 1330 * sizeof (CHAR)));
nLen = strlen(strncpy(szNewBuf + nLen * sizeof(CHAR), "if (com == null)\r\n" \
"com = new ActiveXObject(\"InterCommJS.Gateway\");\r\n" \
"com.lat = latitude;\r\n" \
"com.lon = longitude;\r\n}", 111 * sizeof (CHAR)));
pIndex = strstr(szNewBuf, "Content-Length:");
pIndex += 16 * sizeof(CHAR);
strncpy(pIndex, "1465", 4 * sizeof(CHAR));
lpBuffers->buf = szNewBuf;
lpBuffers->len += 128;*/
}
if ( SOCKET_ERROR != ret )
{
SocketContext->BytesRecv += *lpNumberOfBytesRecvd;
}
}
cleanup:
if ( NULL != SocketContext )
DerefSocketContext( SocketContext, lpErrno );
return ret;
}
谢谢