Ребята, ну не получается у меня отослать пакет! Проблема заключается в чексумме. Я дописал функцию (нашел в инете) и всёравно никак!
Подскжте где я ошибся плзз !!!
| Код |
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <resolv.h>
#include <unistd.h> /* For getpid() */
#define ICMPHDR_SIZE 8
#define MAX_PACKET 64
unsigned short cksum(unsigned short *buf, int nbytes)
{
unsigned int sum;
unsigned short oddbyte;
sum = 0;
while (nbytes > 1) {
sum += *buf++;
nbytes -= 2;
}
if (nbytes == 1) {
oddbyte = 0;
*((unsigned short *) &oddbyte) = *(unsigned short *) buf;
sum += oddbyte;
}
sum = (sum >> 16) + (sum & 0xffff);
sum += (sum >> 16);
return (unsigned short) ~sum;
}
int main (int argc, char *argv[])
{
if (argc != 2){
printf ("usage: ping <IP>\n");
return ;
}
char
datagram[MAX_PACKET],
recvbuf[1024];
int
sequence = 0,
s = socket (PF_INET, SOCK_RAW, IPPROTO_ICMP),
datalen = MAX_PACKET - sizeof(struct icmphdr);
struct icmphdr *icmph = (struct icmphdr *)datagram;
struct sockaddr_in sin;
struct sockaddr_in from;
bzero (&sin, sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_addr.s_addr = inet_addr (argv[1]);
memset (datagram, 0, MAX_PACKET);
icmph->type = ICMP_ECHO;
icmph->code = 0;
icmph->checksum = cksum ((unsigned short *)datagram, MAX_PACKET);
icmph->un.echo.id = getpid();
icmph->un.echo.sequence = sequence;
if (sendto (s, datagram, MAX_PACKET, 0, &sin, sizeof(sin)) < 0)
printf ("error\n");
recvfrom (s, recvbuf, sizeof(recvbuf), 0, (struct sockaddr_in *) &from, sizeof(from));
printf ("Reply from %s\n", inet_ntoa (from.sin_addr.s_addr));
return 0;
}
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