send_v4.c

unix网络编程卷1：套接口API的全书源码

#include	"ping.h"

void
send_v4(void)
{
	int			len;
	struct icmp	*icmp;

	icmp = (struct icmp *) sendbuf;
	icmp->icmp_type = ICMP_ECHO;
	icmp->icmp_code = 0;
	icmp->icmp_id = pid;
	icmp->icmp_seq = nsent++;
	memset(icmp->icmp_data, 0xa5, datalen);	/* fill with pattern */
	Gettimeofday((struct timeval *) icmp->icmp_data, NULL);

	len = 8 + datalen;		/* checksum ICMP header and data */
	icmp->icmp_cksum = 0;
	icmp->icmp_cksum = in_cksum((u_short *) icmp, len);

	Sendto(sockfd, sendbuf, len, 0, pr->sasend, pr->salen);
}