proc_v6.c

来自「unix网络编程第一卷socket编程书上的全部源代码」· C语言 代码 · 共 50 行

#include	"ping.h"

void
proc_v6(char *ptr, ssize_t len, struct msghdr *msg, struct timeval* tvrecv)
{
#ifdef	IPV6
	double				rtt;
	struct icmp6_hdr	*icmp6;
	struct timeval		*tvsend;
	struct cmsghdr		*cmsg;
	int					hlim;

	icmp6 = (struct icmp6_hdr *) ptr;
	if (len < 8)
		return;				/* malformed packet */

	if (icmp6->icmp6_type == ICMP6_ECHO_REPLY) {
		if (icmp6->icmp6_id != pid)
			return;			/* not a response to our ECHO_REQUEST */
		if (len < 16)
			return;			/* not enough data to use */

		tvsend = (struct timeval *) (icmp6 + 1);
		tv_sub(tvrecv, tvsend);
		rtt = tvrecv->tv_sec * 1000.0 + tvrecv->tv_usec / 1000.0;

		hlim = -1;
		for (cmsg = CMSG_FIRSTHDR(msg); cmsg != NULL; cmsg = CMSG_NXTHDR(msg, cmsg)) {
			if (cmsg->cmsg_level == IPPROTO_IPV6 &&
				cmsg->cmsg_type == IPV6_HOPLIMIT) {
				hlim = *(u_int32_t *)CMSG_DATA(cmsg);
				break;
			}
		}
		printf("%d bytes from %s: seq=%u, hlim=",
				len, Sock_ntop_host(pr->sarecv, pr->salen),
				icmp6->icmp6_seq);
		if (hlim == -1)
			printf("???");	/* ancillary data missing */
		else
			printf("%d", hlim);
		printf(", rtt=%.3f ms\n", rtt);
	} else if (verbose) {
		printf("  %d bytes from %s: type = %d, code = %d\n",
				len, Sock_ntop_host(pr->sarecv, pr->salen),
				icmp6->icmp6_type, icmp6->icmp6_code);
	}
#endif	/* IPV6 */
}