/* SPDX-License-Identifier: GPL-2.0 */

#include <errno.h>

#include <string.h>

#include <sys/types.h>

#include <netinet/in.h>

#include <linux/mpls.h>

#include "utils.h"

static const char *mpls_ntop1(const struct mpls_label *addr, char *buf, size_t buflen)

{

	size_t destlen = buflen;

	char *dest = buf;

	int count = 0;

	while (1) {

		uint32_t entry = ntohl(addr[count++].entry);

		uint32_t label = (entry & MPLS_LS_LABEL_MASK) >> MPLS_LS_LABEL_SHIFT;

		int len = snprintf(dest, destlen, "%u", label);

		if (len >= destlen)

			break;

		/* Is this the end? */

		if (entry & MPLS_LS_S_MASK)

			return buf;

		dest += len;

		destlen -= len;

		if (destlen) {

			*dest = '/';

			dest++;

			destlen--;

		}

	}

	errno = -E2BIG;

	return NULL;

}

const char *mpls_ntop(int af, const void *addr, char *buf, size_t buflen)

{

	switch(af) {

	case AF_MPLS:

		errno = 0;

		return mpls_ntop1((struct mpls_label *)addr, buf, buflen);

	default:

		errno = EAFNOSUPPORT;

	}

	return NULL;

}