I'm working with libpcap in C on linux (centos) and I'm following this guide I want to simply print out the entire packet in ascii and i'v managed to get it working by casting it a u_char* in the "my_callback" function. But I can't figure out how to get the length of the data. strstr didn't work. the header has a len member that you can access to get the size but I can't find anything similar for the *packet being passed. Any help is appreciated.