/** \file ipme.c
 * \brief functions to filter out IP addresses of the local machine
 */

#include <ipme.h>

#include <qdns.h>

#include <assert.h>
#include <ifaddrs.h> 
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h> 
#include <sys/types.h> 

/**
 * remove all IP addresses of the local machine from IP list
 *
 * @param ipl list of IP addresses
 * @returns cleaned list
 * @retval NULL all listed addresses are local ones
 *
 * The address structs that match the local machine are freed.
 *
 * If any errors are encountered while this function runs (e.g.
 * a function called runs out of memory) the original list will
 * be returned.
 */
struct ips *
filter_my_ips(struct ips *ipl)
{
	struct ifaddrs *ifap, *curi;
	struct ips *ret = ipl;

	if (getifaddrs(&ifap) != 0)
		return ipl;

	for (curi = ifap; curi != NULL; curi = curi->ifa_next) {
		struct ips *tmp;
		struct ips *prev = NULL;

		if (curi->ifa_addr == NULL)
			continue;

		switch (curi->ifa_addr->sa_family) {
		case AF_INET:
			break;
#ifndef IPV4ONLY
		case AF_INET6:
			break;
#endif /* IPV4ONLY */
		default:
			continue;
		}

		tmp = ret;
		while (tmp != NULL) {
			unsigned short s = 0;
			if (curi->ifa_addr->sa_family == AF_INET) {
				/* either configured as localhost or 127.0.0./8 or 0.0.0.0 */
				for (s = 0; s < tmp->count; s++) {
					if (!IN6_IS_ADDR_V4MAPPED(tmp->addr + s))
						continue;

					if (((tmp->addr[s].s6_addr32[3] != ((struct sockaddr_in *)curi->ifa_addr)->sin_addr.s_addr) &&
							(tmp->addr[s].s6_addr[12] != IN_LOOPBACKNET) && (tmp->addr[s].s6_addr32[3] != 0)))
						continue;

					break;
				}
#ifndef IPV4ONLY
			} else {
				for (s = 0; s < tmp->count; s++)
					if (IN6_ARE_ADDR_EQUAL(tmp->addr + s, &((struct sockaddr_in6 *)curi->ifa_addr)->sin6_addr))
						break;
#endif /* IPV4ONLY */
			}

			if (s == tmp->count) {
				prev = tmp;
				tmp = tmp->next;
				continue;
			}

			if (tmp->count == 1) {
				if (prev) {
					prev->next = tmp->next;
					tmp->next = NULL;
					freeips(tmp);
					tmp = prev->next;
				} else {
					/* the first result was deleted */
					if (ret == tmp)
						ret = ret->next;

					prev = tmp;
					tmp = tmp->next;
					prev->next = NULL;
					freeips(prev);
					prev = NULL;
				}
			} else {
				/* no need to move if the one to be deleted is the last entry anyway */
				struct in6_addr *n;
				tmp->count--;
				if (s != tmp->count)
					memmove(tmp->addr + s, tmp->addr + s + 1, sizeof(*tmp->addr) * (tmp->count - s));

				n = realloc(tmp->addr, sizeof(*tmp->addr) * tmp->count);
				/* if shrinking fails just keep the old pointer */
				if (n != NULL)
					tmp->addr = n;
			}
		}
	}

	freeifaddrs(ifap);

	return ret;
}