get_ifi_info.c

unix下的route源程序

#include	"unpifi.h"
#include	"unproute.h"

/* include get_ifi_info1 */
struct ifi_info *
get_ifi_info(int family, int doaliases)
{
	int 				flags;
	char				*buf, *next, *lim;
	size_t				len;
	struct if_msghdr	*ifm;
	struct ifa_msghdr	*ifam;
	struct sockaddr		*sa, *rti_info[RTAX_MAX];
	struct sockaddr_dl	*sdl;
	struct ifi_info		*ifi, *ifisave, *ifihead, **ifipnext;

	buf = Net_rt_iflist(family, 0, &len);

	ifihead = NULL;
	ifipnext = &ifihead;

	lim = buf + len;
	for (next = buf; next < lim; next += ifm->ifm_msglen) {
		ifm = (struct if_msghdr *) next;
		if (ifm->ifm_type == RTM_IFINFO) {
			if ( ((flags = ifm->ifm_flags) & IFF_UP) == 0)
				continue;	/* ignore if interface not up */

			sa = (struct sockaddr *) (ifm + 1);
			get_rtaddrs(ifm->ifm_addrs, sa, rti_info);
			if ( (sa = rti_info[RTAX_IFP]) != NULL) {
				ifi = Calloc(1, sizeof(struct ifi_info));
				*ifipnext = ifi;			/* prev points to this new one */
				ifipnext = &ifi->ifi_next;	/* ptr to next one goes here */

				ifi->ifi_flags = flags;
				if (sa->sa_family == AF_LINK) {
					sdl = (struct sockaddr_dl *) sa;
					ifi->ifi_index = sdl->sdl_index;
					if (sdl->sdl_nlen > 0)
						snprintf(ifi->ifi_name, IFI_NAME, "%*s",
								 sdl->sdl_nlen, &sdl->sdl_data[0]);
					else
						snprintf(ifi->ifi_name, IFI_NAME, "index %d",
								 sdl->sdl_index);

					if ( (ifi->ifi_hlen = sdl->sdl_alen) > 0)
						memcpy(ifi->ifi_haddr, LLADDR(sdl),
							   min(IFI_HADDR, sdl->sdl_alen));
				}
			}
/* end get_ifi_info1 */

/* include get_ifi_info3 */
		} else if (ifm->ifm_type == RTM_NEWADDR) {
			if (ifi->ifi_addr) {	/* already have an IP addr for i/f */
				if (doaliases == 0)
					continue;

					/* 4we have a new IP addr for existing interface */
				ifisave = ifi;
				ifi = Calloc(1, sizeof(struct ifi_info));
				*ifipnext = ifi;			/* prev points to this new one */
				ifipnext = &ifi->ifi_next;	/* ptr to next one goes here */
				ifi->ifi_flags = ifisave->ifi_flags;
				ifi->ifi_index = ifisave->ifi_index;
				ifi->ifi_hlen = ifisave->ifi_hlen;
				memcpy(ifi->ifi_name, ifisave->ifi_name, IFI_NAME);
				memcpy(ifi->ifi_haddr, ifisave->ifi_haddr, IFI_HADDR);
			}

			ifam = (struct ifa_msghdr *) next;
			sa = (struct sockaddr *) (ifam + 1);
			get_rtaddrs(ifam->ifam_addrs, sa, rti_info);

			if ( (sa = rti_info[RTAX_IFA]) != NULL) {
				ifi->ifi_addr = Calloc(1, sa->sa_len);
				memcpy(ifi->ifi_addr, sa, sa->sa_len);
			}

			if ((flags & IFF_BROADCAST) &&
				(sa = rti_info[RTAX_BRD]) != NULL) {
				ifi->ifi_brdaddr = Calloc(1, sa->sa_len);
				memcpy(ifi->ifi_brdaddr, sa, sa->sa_len);
			}

			if ((flags & IFF_POINTOPOINT) &&
				(sa = rti_info[RTAX_BRD]) != NULL) {
				ifi->ifi_dstaddr = Calloc(1, sa->sa_len);
				memcpy(ifi->ifi_dstaddr, sa, sa->sa_len);
			}

		} else
			err_quit("unexpected message type %d", ifm->ifm_type);
	}
	/* "ifihead" points to the first structure in the linked list */
	return(ifihead);	/* ptr to first structure in linked list */
}
/* end get_ifi_info3 */

void
free_ifi_info(struct ifi_info *ifihead)
{
	struct ifi_info	*ifi, *ifinext;

	for (ifi = ifihead; ifi != NULL; ifi = ifinext) {
		if (ifi->ifi_addr != NULL)
			free(ifi->ifi_addr);
		if (ifi->ifi_brdaddr != NULL)
			free(ifi->ifi_brdaddr);
		if (ifi->ifi_dstaddr != NULL)
			free(ifi->ifi_dstaddr);
		ifinext = ifi->ifi_next;		/* can't fetch ifi_next after free() */
		free(ifi);					/* the ifi_info{} itself */
	}
}

struct ifi_info *
Get_ifi_info(int family, int doaliases)
{
	struct ifi_info	*ifi;

	if ( (ifi = get_ifi_info(family, doaliases)) == NULL)
		err_quit("get_ifi_info error");
	return(ifi);
}