0

Similar to: Howto set the UDP source address on Windows It doesn't work for me. Unable to setup source port and get error:

I have created socket:

bool CUDPTransport::OpenConnection(void) {
    // Create UDP socket
    this->m_hSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if (this->m_hSocket == INVALID_SOCKET) {
        return false;
    }

    // Success
    return true;
}

and I am able to send by UDP transport:

bool CUDPTransport::SendMessage(const CString& sBuffer, const CSyslogOptions& oSyslogOptions) {
    // Convert using the local code page
    CT2A sASCII(sBuffer);

    // Create address
    struct sockaddr_in sin;
    memset(&sin, 0, sizeof(sin));
    sin.sin_family = AF_INET;
    sin.sin_port = htons(this->m_nPort);
    sin.sin_addr.s_addr = htonl(this->m_nCollectorIPv4);

    // Create buffer to send
    WSABUF oBuffer;
    oBuffer.buf = sASCII.m_psz;
    oBuffer.len = (int)strlen(sASCII.m_psz);

    // Declare
    char aControlData[WSA_CMSG_SPACE(sizeof(struct in_pktinfo))];
    memset(&aControlData, 0, sizeof(aControlData));

    // Create a message
    WSAMSG oMessage;
    memset(&oMessage, 0, sizeof(oMessage));
    oMessage.name = (struct sockaddr*)&sin;
    oMessage.namelen = sizeof(sin);
    oMessage.lpBuffers = &oBuffer;
    oMessage.dwBufferCount = 1;
    /* TODO: set source address
    oMessage.Control.buf = (char*)&aControlData;
    oMessage.Control.len = sizeof(aControlData);

    // Create messge header
    WSACMSGHDR* oHeader = WSA_CMSG_FIRSTHDR(&oMessage);
    // memset(oHeader, 0, WSA_CMSG_SPACE(sizeof(struct in_pktinfo)));
    oHeader->cmsg_level = IPPROTO_IP;
    oHeader->cmsg_type = IP_PKTINFO;
    oHeader->cmsg_len = WSA_CMSG_LEN(sizeof(struct in_pktinfo));
    struct in_pktinfo* pktinfo = (struct in_pktinfo*)WSA_CMSG_DATA(oHeader);
    pktinfo->ipi_addr.s_addr = htonl(oSyslogOptions.m_nSenderIPv4);
    */

    // Declare variable
    unsigned long nSentBytes = 0;

    // Send an initial buffer
    int nResult = WSASendMsg(this->m_hSocket, &oMessage, 0, &nSentBytes, NULL, NULL);
    if (nResult == SOCKET_ERROR) {
        int nErrorNo = this->getSocketLastOSErrorNo();
        CString sErrorMsg = this->getSocketLastOSErrorString(nErrorNo);
        closesocket(this->m_hSocket);
        return false;
    }
    return true;
}

When I wish to set up source IP address I uncomment working with control data

bool CUDPTransport::SendMessage(const CString& sBuffer, const CSyslogOptions& oSyslogOptions) {
    // Convert using the local code page
    CT2A sASCII(sBuffer);

    // Create address
    struct sockaddr_in sin;
    memset(&sin, 0, sizeof(sin));
    sin.sin_family = AF_INET;
    sin.sin_port = htons(this->m_nPort);
    sin.sin_addr.s_addr = htonl(this->m_nCollectorIPv4);

    // Create buffer to send
    WSABUF oBuffer;
    oBuffer.buf = sASCII.m_psz;
    oBuffer.len = (int)strlen(sASCII.m_psz);

    // Declare
    char aControlData[WSA_CMSG_SPACE(sizeof(struct in_pktinfo))];
    memset(&aControlData, 0, sizeof(aControlData));

    // Create a message
    WSAMSG oMessage;
    memset(&oMessage, 0, sizeof(oMessage));
    oMessage.name = (struct sockaddr*)&sin;
    oMessage.namelen = sizeof(sin);
    oMessage.lpBuffers = &oBuffer;
    oMessage.dwBufferCount = 1;
    oMessage.Control.buf = (char*)&aControlData;
    oMessage.Control.len = sizeof(aControlData);

    // Create messge header
    WSACMSGHDR* oHeader = WSA_CMSG_FIRSTHDR(&oMessage);
    // memset(oHeader, 0, WSA_CMSG_SPACE(sizeof(struct in_pktinfo)));
    oHeader->cmsg_level = IPPROTO_IP;
    oHeader->cmsg_type = IP_PKTINFO;
    oHeader->cmsg_len = WSA_CMSG_LEN(sizeof(struct in_pktinfo));
    struct in_pktinfo* pktinfo = (struct in_pktinfo*)WSA_CMSG_DATA(oHeader);
    pktinfo->ipi_addr.s_addr = htonl(oSyslogOptions.m_nSenderIPv4);

    // Declare variable
    unsigned long nSentBytes = 0;

    // Send an initial buffer
    int nResult = WSASendMsg(this->m_hSocket, &oMessage, 0, &nSentBytes, NULL, NULL);
    if (nResult == SOCKET_ERROR) {
        int nErrorNo = this->getSocketLastOSErrorNo();
        CString sErrorMsg = this->getSocketLastOSErrorString(nErrorNo);
        closesocket(this->m_hSocket);
        return false;
    }
    return true;
}

and get error with errno: 10022 and message: "An invalid argument was supplied". Does anybody can help me to understand the problem? Thanks!

AnnAgf
  • 31
  • 2
  • [WSASendMsg](https://learn.microsoft.com/en-us/windows/win32/api/winsock2/nf-winsock2-wsasendmsg): *"The socket descriptor in the s parameter must be opened with the socket type set to SOCK_DGRAM or SOCK_RAW."* Is that what you're doing? – IInspectable Aug 04 '20 at 12:46
  • yes, "this->m_hSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP)". SOCK_DGRAM – AnnAgf Aug 04 '20 at 13:01

1 Answers1

0

-1.Error resolved by bind:

bool CUDPTransport::OpenConnection(void) {
    // Create UDP socket
    this->m_hSocket = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if (this->m_hSocket == INVALID_SOCKET) {
        return false;
    }

    // Create source address (2130706433 =  127.0.0.1)
    struct sockaddr_in sin;
    memset(&sin, 0, sizeof(sin));
    sin.sin_family = AF_INET;
    sin.sin_port = 0;
    sin.sin_addr.s_addr = htonl(2130706433);

    // Bind socker
    int nResult = bind(this->m_hSocket, (struct sockaddr*)&sin, sizeof(sin));
    if (nResult == SOCKET_ERROR) {
        int nErrorNo = this->getSocketLastOSErrorNo();
        CString sErrorMsg = this->getSocketLastOSErrorString(nErrorNo);
        closesocket(this->m_hSocket);
        return false;
    }


    // Success
    return true;
}

-2.Send method is working fine.

bool CUDPTransport::SendMessage(const CString& sBuffer, const CSyslogOptions& oSyslogOptions) {

    // Convert using the local code page
    CT2A sASCII(sBuffer);

    // Create address
    struct sockaddr_in sin;
    memset(&sin, 0, sizeof(sin));
    sin.sin_family = AF_INET;
    sin.sin_port = htons(this->m_nPort);
    sin.sin_addr.s_addr = htonl(this->m_nCollectorIPv4);

    // Create buffer to send
    WSABUF oBuffer;
    oBuffer.buf = sASCII.m_psz;
    oBuffer.len = (int)strlen(sASCII.m_psz);

    // Declare
    char aControlData[WSA_CMSG_SPACE(sizeof(struct in_pktinfo))];
    memset(&aControlData, 0, sizeof(aControlData));

    // Create a message
    WSAMSG oMessage;
    memset(&oMessage, 0, sizeof(oMessage));
    oMessage.name = (struct sockaddr*)&sin;
    oMessage.namelen = sizeof(sin);
    oMessage.lpBuffers = &oBuffer;
    oMessage.dwBufferCount = 1;
    oMessage.Control.buf = (char*)&aControlData;
    oMessage.Control.len = sizeof(aControlData);

    // Create message header
    WSACMSGHDR* oHeader = WSA_CMSG_FIRSTHDR(&oMessage);
    memset(oHeader, 0, WSA_CMSG_SPACE(sizeof(struct in_pktinfo)));
    oHeader->cmsg_level = IPPROTO_IP;
    oHeader->cmsg_type = IP_PKTINFO;
    oHeader->cmsg_len = WSA_CMSG_LEN(sizeof(struct in_pktinfo));
    struct in_pktinfo* pktinfo = (struct in_pktinfo*)WSA_CMSG_DATA(oHeader);
    pktinfo->ipi_addr.s_addr = htonl(oSyslogOptions.m_nSenderIPv4);

    // Declare variable
    unsigned long nSentBytes = 0;

    // Send an initial buffer
    int nResult = WSASendMsg(this->m_hSocket, &oMessage, 0, &nSentBytes, NULL, NULL);
    if (nResult == SOCKET_ERROR) {
        int nErrorNo = this->getSocketLastOSErrorNo();
        CString sErrorMsg = this->getSocketLastOSErrorString(nErrorNo);
        closesocket(this->m_hSocket);
        return false;
    }
    return true;
}

-3.But source ip address is not changed due to https://security.stackexchange.com/questions/184001/is-ip-spoofing-possible-in-windows-desktop-with-user-privileges

AnnAgf
  • 31
  • 2