Дополнительный заголовок маршрутизации IPv6

#include "netinet/in.h"
#include <string.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <errno.h>
#include <stdio.h>

#define MAXPACKET   128000 

int main()
{
    // ===========================
    // Set the socket name
    struct sockaddr_in6 hop1;

    hop1.sin6_family = PF_INET6;
    hop1.sin6_flowinfo = 0;
    hop1.sin6_port = 0;
   
    // Set address
    inet_pton(AF_INET6, "2001:640:11:1::2", &hop1.sin6_addr);  
 
    // ===========================
    // Form the packet (main header and an optional routing header)
    u_char outpack[MAXPACKET];
    int i=0;   

    // protocol version (4 bits)
    // traffic class (8 bits)
    // 20 bits flow-ID
    outpack[i++] = 0x60;   
    outpack[i++] = 0x00;
    outpack[i++] = 0x00;   
    outpack[i++] = 0x00;

    // payload length
    outpack[i++] = 0x00;
    outpack[i++] = 0x28;

    // next header
    outpack[i++] = 0x2b;
    // hop limit
    outpack[i++] = 0xff;

    // source address
    outpack[i++] = 0x20;
    outpack[i++] = 0x01;

    outpack[i++] = 0x06;
    outpack[i++] = 0x40;

    outpack[i++] = 0x00;
    outpack[i++] = 0x11;

    outpack[i++] = 0x00;
    outpack[i++] = 0x01;

    outpack[i++] = 0x00;
    outpack[i++] = 0x00;

    outpack[i++] = 0x00;
    outpack[i++] = 0x00;

    outpack[i++] = 0x00;
    outpack[i++] = 0x00;

    outpack[i++] = 0x00;
    outpack[i++] = 0x01;

    // destination address
    outpack[i++] = 0x20;
    outpack[i++] = 0x01;

    outpack[i++] = 0x06;
    outpack[i++] = 0x40;

    outpack[i++] = 0x00;
    outpack[i++] = 0x11;

    outpack[i++] = 0x00;
    outpack[i++] = 0x02;

    outpack[i++] = 0x00;
    outpack[i++] = 0x00;

    outpack[i++] = 0x00;
    outpack[i++] = 0x00;

    outpack[i++] = 0x00;
    outpack[i++] = 0x00;

    outpack[i++] = 0x00;
    outpack[i++] = 0x02;
   
    //======================
    // optional header
    outpack[i++] = 0x3b;
    outpack[i++] = 0x04;//length of the Routing header
    outpack[i++] = 0x00;//Routing Type
    outpack[i++] = 0x02;//Segments Left

    outpack[i++] = 0x00;
    outpack[i++] = 0x00;
    outpack[i++] = 0x00;
    outpack[i++] = 0x00;

    // route address #1
    outpack[i++] = 0x20;
    outpack[i++] = 0x01;

    outpack[i++] = 0x06;
    outpack[i++] = 0x40;

    outpack[i++] = 0x00;
    outpack[i++] = 0x11;

    outpack[i++] = 0x00;
    outpack[i++] = 0x02;

    outpack[i++] = 0x00;
    outpack[i++] = 0x00;

    outpack[i++] = 0x00;
    outpack[i++] = 0x00;

    outpack[i++] = 0x00;
    outpack[i++] = 0x00;

    outpack[i++] = 0x00;
    outpack[i++] = 0x01;

    // route address #2
    outpack[i++] = 0x20;
    outpack[i++] = 0x01;

    outpack[i++] = 0x06;
    outpack[i++] = 0x40;

    outpack[i++] = 0x00;
    outpack[i++] = 0x11;

    outpack[i++] = 0x00;
    outpack[i++] = 0x02;

    outpack[i++] = 0x00;
    outpack[i++] = 0x00;

    outpack[i++] = 0x00;
    outpack[i++] = 0x00;

    outpack[i++] = 0x00;
    outpack[i++] = 0x00;

    outpack[i++] = 0x00;
    outpack[i++] = 0x02;

   
    struct iovec iov;
    iov.iov_len = i;
    iov.iov_base = outpack;

    // ===========================
    // Form header
    struct msghdr mhdr;
   
    memset(&mhdr, 0, sizeof(mhdr));

    mhdr.msg_name = (caddr_t) &hop1;
    mhdr.msg_namelen = sizeof(struct sockaddr_in6);
    mhdr.msg_iov = &iov;
    mhdr.msg_iovlen = 1;

    // create RAW socket
    int sock = socket(PF_INET6, SOCK_RAW, IPPROTO_RAW);
    if (sock < 0)
    {
        return 1;
    }

    // send IP-packet
    if (sendmsg(sock, &mhdr, 0) < 0)
    {
        return 1;
    }

    return 0;
}