Hello all, I face a strange problem of libpcap.

On my WRT54GL with openwrt RC6, I can run "tcpdump ether src aa:bb:cc:dd:ee:ff" successfully, the tcpdump grabs packets from the source aa:bb:cc:dd:ee:ff , no matter what the type of packet is.  Then when I run a self-design program which use libpcap to do the same job, i.e. set the filter with "ether src aa:bb:cc:dd:ee:ff", the program cannot work probably. For the ICMP (ping) packets, the program can only the grab first 6 packets, after that it can't grab any ICMP packet anymore. For the TCP packets, it can only grab part of the packet, some packets is missed.

Anyone knows what I should do? (I attached the simplified code of my program)

Thanks a lot.

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#define MONITOR "prism0"
#include<stdio.h>
#include<stdlib.h>
#include <pcap.h>

int main(){
    pcap_t *hIf;
    struct bpf_program filter;   
    char filter_str[]="ether src AA:BB:CC:DD:EE:FF\0";
    const unsigned char *packet;
    struct pcap_pkthdr header;
    char pcapErrBuf[PCAP_ERRBUF_SIZE];                    
    int count = 0;
   
    hIf = pcap_open_live(MONITOR, BUFSIZ, 1, 0, pcapErrBuf);
    if (!hIf){       
            return 0;
    }
    if ( pcap_compile(hIf, &filter, filter_str, 0, 0) == -1 ){       
        return 0;
    }
    if ( pcap_setfilter(hIf, &filter) == -1){       
        return 0;
    }           
    while (count < 10) {       
        int read = 0;       
        packet = pcap_next(hIf, &header);                                                     
            if ( packet ){
                printf("Count = %d\n",++count);                                                  
            }       
        }               
        pcap_close(hIf);
}