tcp_hdr
th = tcp_hdr(skb);
struct tcphdr *tcp_hdr = NULL;
tcp_hdr = (struct tcphdr *)((char*)ip4_hdr + sizeof(struct ip));
tcp_hdr = (struct tcphdr *)((char*)ip6 + sizeof(struct ip6_hdr));
tcp_hdr->th_ack = htonl(cqe2->tcp_ack_num);
tcp_set_flags(tcp_hdr, tcp_get_flags(tcp_hdr) | TH_PUSH);
tcp_hdr->th_win = htons(cqe2->tcp_window);
tcp_hdr->th_sum = 0xffff;
p = (uint32_t *)((char*)tcp_hdr + sizeof(struct tcphdr) + 2);