Dos libpcap free memory ifself?

Question

My program use libpcap like this:

while pcaket = pcap_next() {

...

(modify the pcaket and do checksum)

...

pcap_sendpacket(pcaket) 

}

Recently, I found there is a memory leak in my program...

My question is: Will the libpcap free the pcaket after pcap_next? or I have to do the free work myself ?

Answer 1

Will the libpcap free the pcaket after pcap_next?

The packet is contained in a buffer internal to libpcap (attached to the pcap_t); a new buffer is not allocated for each packet, so the buffer isn't freed after pcap_next(), it's freed after the pcap_t is closed. You do not have to free it yourself.

(This also means that the packet data from a particular call to pcap_next() or pcap_next_ex() is not guaranteed to remain valid after the next call to pcap_next() or pcap_next_ex() - or pcap_loop() or pcap_dispatch(); it might be overwritten with data from the next packet or the next batch of packets.)