ping6test.cpp

/**
 * ICMPv6 echo request (ping6) test
 */

#include <unistd.h>
#include <sys/socket.h>

#include <arpa/inet.h>
#include <netinet/icmp6.h>

#include <iostream>

int main()
{
    struct sockaddr_in6 whereto;
    whereto.sin6_family = AF_INET6;
    whereto.sin6_port = htons(0);
    inet_pton(AF_INET6, "2001:4860:4860::8888"/*Google Public DNS*/, &whereto.sin6_addr);

    auto sock = socket(AF_INET6, SOCK_RAW, IPPROTO_ICMPV6); // You need to be root to do this

    // https://tools.ietf.org/html/rfc4443
    unsigned char buf[sizeof(struct icmp6_hdr) + 8];
    auto icmph = (struct icmp6_hdr *)buf;
    icmph->icmp6_type = ICMP6_ECHO_REQUEST;
    icmph->icmp6_code = 0;
    icmph->icmp6_cksum = 0;
    icmph->icmp6_seq= 1;
    icmph->icmp6_id= 0;
    strcpy((char*)buf + sizeof(struct icmp6_hdr), "RUTHERE");

    auto n = sendto(sock, buf, sizeof(buf), 0/*flags*/, (struct sockaddr *)&whereto, sizeof(struct sockaddr_in6));
    std::cout << (int)n << " bytes sent" << std::endl;

    n = recvfrom(sock, buf, sizeof(buf), 0, NULL, NULL); // blocks until reply packet arrives(possibly forever)
    std::cout << (int)n << " bytes received. code=" << (int)buf[0] << std::endl;
    close(sock);
}