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POerror running a simple libpcap example
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  1. POerror running a simple libpcap example
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    copied!<p>I am trying to compile a simple libpcap example, </p> <pre><code>#include&lt;stdio.h&gt; #include&lt;pcap.h&gt; int main(int argc, char *argv[]) { char *dev; char errbuf[PCAP_ERRBUF_SIZE]; struct bpf_program fp; char filter_exp[] = "port 23"; bpf_u_int32 mask; bpf_u_int32 net; dev = pcap_lookupdev(errbuf); if (dev == NULL ) { fprintf(stderr, "couldn't find default device: %s\n", errbuf); return (2); } printf("Device: %s\n", dev); //LOOKUP NETMASK and IP if (pcap_lookupnet(dev, &amp;net, &amp;mask, errbuf) == -1) { fprintf(stderr, "can't get netmask for device %s\n", dev); net = 0; mask = 0; } printf("lookup\n"); pcap_t *handle; printf("handle defined\n"); handle = pcap_open_live(dev, BUFSIZ, 1, 1000, errbuf); printf("opened\n"); if (handle = NULL ) { fprintf(stderr, "Couldn't open device %s: %s\n", dev, errbuf); return (2); } printf("pcap_open\n"); if ((pcap_compile(handle, &amp;fp, filter_exp, 1, net)) == -1) { printf("compile error block entered\n"); fprintf(stderr, "Couldn't parse filter %s: %s\n", filter_exp, pcap_geterr(handle)); return (2); } printf("compiled\n"); if (pcap_setfilter(handle, &amp;fp) == -1) { fprintf(stderr, "couldn't install filter %s: %s\n", filter_exp, pcap_geterr(handle)); return (2); } printf("after filter\n"); return (0); } </code></pre> <p>It compiles without error, but when I try to run it, I'm getting segmentation fault message or if I try to run it with root permission, I don't get the message but the program stops after printing </p> <pre><code>Device: eth0 lookup handle defined opened pcap_open </code></pre> <p>Can you please help me with this, I'm confused as to why this error happens. Thanks in advance.</p>
 

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