Raw Socket Linux send/receive a packet

Question

Have some problems in receiving packets. I can receive and read incoming packets, but I think i do not get a handshake with any host. I only want to send a packet to a remot

Answer 1

ip = (struct iphdr*) buffer;
tcp = (struct tcphdr*) (buffer + sizeof(struct tcphdr)); //This is wrong

Here to get array index of tcp header in buffer, you need to add sizeof(struct iphdr) to buffer like mentioned below.

ip = (struct iphdr*) buffer;
tcp = (struct tcphdr*) (buffer + sizeof(struct iphdr)); //This is correct