пытаюсь отправить пакет через raw socket
вот типа пакет, но я не могу понять куда писать данные для отправки?
данные это payload

  iph->ip_hl = 5;
  iph->ip_v = 4;
  iph->ip_tos = 0;
  iph->ip_len = sizeof (struct ip) + sizeof (struct tcphdr);
  iph->ip_id = htonl (54321);    /* the value doesn't matter here */
  iph->ip_off = 0;
  iph->ip_ttl = 255;
  iph->ip_p = 6;
  iph->ip_sum = 0;        /* set it to 0 before computing the actual checksum later */
  iph->ip_src.s_addr = inet_addr ("1.2.3.4");/* SYN's can be blindly spoofed */
  iph->ip_dst.s_addr = sin.sin_addr.s_addr;
  tcph->th_sport = htons (1234);    /* arbitrary port */
  tcph->th_dport = htons (P);
  tcph->th_seq = random ();/* in a SYN packet, the sequence is a random */
  tcph->th_ack = 0;/* number, and the ack sequence is 0 in the 1st packet */
  tcph->th_x2 = 0;
  tcph->th_off = 0;        /* first and only tcp segment */
  tcph->th_flags = TH_SYN;    /* initial connection request */
  tcph->th_win = htonl (65535);    /* maximum allowed window size */
  tcph->th_sum = 0;/* if you set a checksum to zero, your kernel's IP stack
              should fill in the correct checksum during transmission */
  tcph->th_urp = 0;