tcpdump mailing list archives
Re: Packet captured with PCAP
From: "Mustafa Abu Sedera" <tifa_80 () hotmail com>
Date: Thu, 13 Mar 2003 15:55:21 +0000
I begin to work with pcap and I have some problem. I would only see packet contents on my screen. First I called pcap_loop like this... pcap_loop(handle,-1,traitement_pkt,NULL); /*My callback function is*/ void traitement_pkt(u_char *args, const struct pcap_pkthdr *header, const u_char *packet) { printf("Voici le paquet capture via pcap_loop\n%s\n",packet); }
I had the same problem in the beginning but then i concluded this:the packet is not stored as a NULL terminated string, it is stored as an array of chars. each char contains one byte of the received packet. the reason for this i think is that the packet may contain bytes with the value 0x00 which would be understood as a string termination although the packet contains more bytes after it. in your case probably the packet contained a 0x00 as the first byte so printf() thinks that it is an empty string.
any way, print the contents of packet like this: for(i=0; i<header->caplen; i++) {printf("%.2x ",packet[i]);//prints the char(byte) in hex format- //2 digits then space
if((i+1)%20==0)printf("\n");//every 20 bytes start a new line }
Another question, where can I see archives from Jan and Feb 2003? The following link stop at December 2002: http://www.tcpdump.org/lists/workers/
please tell me when you know where.by the way, i found a very good documentation about pcap library at the winpcap site(you can find it through tcpdump.org) . download the developer pack. this will contain any information you will EVER need about pcap.
good luck and if you need anything let me know _________________________________________________________________Tired of spam? Get advanced junk mail protection with MSN 8. http://join.msn.com/?page=features/junkmail
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Current thread:
- Packet captured with PCAP Marc-André Breton (Mar 12)
- Re: Packet captured with PCAP Jacky Buyck (Mar 13)
- <Possible follow-ups>
- RE: Packet captured with PCAP Allison, Jason (JALLISON) (Mar 12)
- Re: Packet captured with PCAP Mustafa Abu Sedera (Mar 13)