MSS Option & TTL Filter

[Martin Defeche <martin.defeche () gmail com>]

Hello,

I am developping a sniffer which its goal is to gather information about MSS
and TTL, so I put a filer (tcp[tcpflags] & tcp-syn != 0) to catch only SYN
or SYN ACK TCP packet.

My problem is that I do not get all the packets (I compared with wireshark)
and I do not understand why ! I have been searching since two days without
any solutions ...

I use the pcap_next function because I have to maintain a MySQL connection
that could not fit with a pcap function with a callback.

I purified my code to let you see only the sniffer part (very small). It's
using pthread because I use two concurrent sniffer (IPv4 + IPv6 --> IPv6 is
not present in the program).

Please can you help me :)

To compile : g++ --pedantic -Wall -O3 -g -W -pthread -I/usr/include
sniffer.cpp -lpcap
To run         : ./a.out <IPv4 interface name>

Thanks in advance

Attachment: sniffer.cpp
Description:

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