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Question: Problem in doing RAW SOCKET Programming

Forum: The Linux Kernel Hackers' Guide
Keywords: Client server program using Raw sockets.
Date: Wed, 30 Apr 1997 15:39:27 GMT
From: anjali sharma <>

I have to write a client server program using raw socket. I have written the code for client as well as server but when ever I run it my server hangs up. So I have to reboot the server. I think there is problem with my send and receive. I am sending the code for server. Hope you would be able to help me.

@@@@@@@@@@@@@@@@@@@@@@@ code @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

#include <stdio.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

#include <netinet/ip.h>
#include <netinet/ip_icmp.h>

u_short portbase = 0; long time();

#define qlen 6
#define protocol "raw"
#define FIX(x) htons(x)
#define FIX(x) (x)

main(int argc, char **argv)
    int msock, ssock;
    int alen;
    char buf[] = "asdfgh";
    char recv_buffer[20];
    struct servent *pse;
    struct protoent *ppe;
    struct sockaddr_in dst;
    struct hostent *hp;
    struct ip *ip = (struct ip *)buf;
    struct icmp *icmp = (struct icmp *)(ip +1);

    int s, type, dstL;
    int q, bind1, lis;
    int sockopt;
    int on = 1, address;
    int offset;
    int sendbuff;
    int n;
    bzero((char *)&dst, sizeof(dst));
    dst.sin_family = AF_INET;

    dst.sin_port = 6000;
    ppe = getprotobyname("raw");

    s = socket(AF_INET, SOCK_RAW, 0);
    printf("\n%d value of s in servsock",s);
    if (s < 0)
        printf("\nCann't creat socket");


    sockopt = setsockopt(s, 0, IP_HDRINCL, &on, sizeof(on));
    printf("\n%d value of sockopt", sockopt);
    if (sockopt < 0)

    if(( hp = gethostbyname(argv[1])) == NULL){
        if(ip->ip_dst.s_addr = inet_addr(argv[1]) == -1)
             printf("\nERROR: UNKNOWN HOST");
        bcopy(hp->h_addr_list[0], &ip->ip_dst.s_addr,                            hp->h_length);
    printf("\nSending to %s\n", inet_ntoa(ip->ip_dst));

    ip->ip_v = 4;
    ip->ip_hl = sizeof *ip >> 2;
    ip>ip_tos = 0;
    ip->ip_len = sizeof buf;
    ip->ip_id = htons(4321);
    ip->ip_off = 0;
    ip->ip_ttl = 255;
    ip->ip_p = 1;
    ip->ip_sum = 0;
    ip->ip_src.s_addr = 0;
    dst.sin_addr = ip->ip_dst;
    dst.sin_family = AF_INET;

    icmp->icmp_type = ICMP_ECHO;
    icmp->icmp_code = 0;
    sendbuff = sendto(s, buf, sizeof buf, 0, (struct sockaddr                          *) &dst, sizeof dst);
        if(sendbuff < 0)
                printf(" ERROR sending ");
        if ( sendbuff != sizeof buf)
                printf("ERROR packet size");
        printf("\n buf is %s value of send is %d ", buf, sendbuff);

        dstL = sizeof dst;
        n = recvfrom(s, recv_buffer, sizeof(recv_buffer), 0,
         (struct sockaddr *) &dst,&dstL);

printf("recv buffer is%s value of n is %d\n", recv_buffer,n); close(s); exit(0); } @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@