[Winpcap-users] sniffing multiple interfaces

[Vasanth Neel]

Hello Everyone,

I had a requirement to sniff multiple interfaces to rtp pckets. Our
application is stable when we sniff single interface but when i try to
sniff multiple interface from single or multiple thread each opens the
pcap_t devices seperately and uses pcap_next_ex to read the packets i got
packet loss in large amount. i have tried to set the timeot to different
levels like from 1 to 500 nothing seems to work.. here is the code sample
that process the the multiple interfaces,

while(IsRunning())
 {

  pcap_pkthdr* header;
  const u_char* pkt_data;
  bool bProcess = true;
  if(pcap_next_ex(m_hPcap1,&header,&pkt_data) >= 0)
  {
    ETHERNETHEADER* pEthernetHeader = (ETHERNETHEADER *) pkt_data;
    IPHEADER* pIpHeader = (IPHEADER*)((char*)pEthernetHeader +
sizeof(ETHERNETHEADER));
    u_char* ipPacketEnd = (u_char*)pIpHeader + ntohs(pIpHeader->ip_len);
    PacketSize = (ipPacketEnd - pkt_data)+100; // winpcap padding

    u_char* pPacket = (u_char*) malloc(PacketSize);
    memcpy(pPacket,pkt_data,PacketSize);
    m_SafeQueue.Enqueue(pPacket);
  }
  if(pcap_next_ex(m_hPcap2,&header,&pkt_data) >= 0)
  {
    ETHERNETHEADER* pEthernetHeader = (ETHERNETHEADER *) pkt_data;
    IPHEADER* pIpHeader = (IPHEADER*)((char*)pEthernetHeader +
sizeof(ETHERNETHEADER));
    u_char* ipPacketEnd = (u_char*)pIpHeader + ntohs(pIpHeader->ip_len);
    PacketSize = (ipPacketEnd - pkt_data)+100; // winpcap padding

    u_char* pPacket = (u_char*) malloc(PacketSize);
    memcpy(pPacket,pkt_data,PacketSize);
    m_SafeQueue.Enqueue(pPacket);
  }
}


What i am doing wrong in this? also i have seems some suggestion to use
waitformultipleevents but i am not sure how to do that. any suggestions
appreciated.
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