sock_ntop.c

Unix网络编程 基于Socket的网络编程

#include	"unp.h"

#ifdef	HAVE_SOCKADDR_DL_STRUCT
# include	<net/if_dl.h>
#endif

/* include sock_ntop */
char *
sock_ntop(const struct sockaddr *sa, socklen_t salen)
{
    char		portstr[7];
    static char str[128];		/* Unix domain is largest */

	switch (sa->sa_family) {
	case AF_INET: {
		struct sockaddr_in	*sin = (struct sockaddr_in *) sa;

		if (inet_ntop(AF_INET, &sin->sin_addr, str, sizeof(str)) == NULL)
			return(NULL);
		if (ntohs(sin->sin_port) != 0) {
			snprintf(portstr, sizeof(portstr), ".%d", ntohs(sin->sin_port));
			strcat(str, portstr);
		}
		return(str);
	}
/* end sock_ntop */

#ifdef	IPV6
	case AF_INET6: {
		struct sockaddr_in6	*sin6 = (struct sockaddr_in6 *) sa;

		if (inet_ntop(AF_INET6, &sin6->sin6_addr, str, sizeof(str)) == NULL)
			return(NULL);
		if (ntohs(sin6->sin6_port) != 0) {
			snprintf(portstr, sizeof(portstr), ".%d", ntohs(sin6->sin6_port));
			strcat(str, portstr);
		}
		return(str);
	}
#endif

#ifdef	AF_UNIX
	case AF_UNIX: {
		struct sockaddr_un	*unp = (struct sockaddr_un *) sa;

			/* OK to have no pathname bound to the socket: happens on
			   every connect() unless client calls bind() first. */
		if (unp->sun_path[0] == 0)
			strcpy(str, "(no pathname bound)");
		else
			snprintf(str, sizeof(str), "%s", unp->sun_path);
		return(str);
	}
#endif

#ifdef	HAVE_SOCKADDR_DL_STRUCT
	case AF_LINK: {
		struct sockaddr_dl	*sdl = (struct sockaddr_dl *) sa;

		if (sdl->sdl_nlen > 0)
			snprintf(str, sizeof(str), "%*s",
					 sdl->sdl_nlen, &sdl->sdl_data[0]);
		else
			snprintf(str, sizeof(str), "AF_LINK, index=%d", sdl->sdl_index);
		return(str);
	}
#endif
	default:
		snprintf(str, sizeof(str), "sock_ntop: unknown AF_xxx: %d, len %d",
				 sa->sa_family, salen);
		return(str);
	}
    return (NULL);
}

char *
Sock_ntop(const struct sockaddr *sa, socklen_t salen)
{
	char	*ptr;

	if ( (ptr = sock_ntop(sa, salen)) == NULL)
		err_sys("sock_ntop error");	/* inet_ntop() sets errno */
	return(ptr);
}