ip/ipprefix.c

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
 * Copyright (C)2005 USAGI/WIDE Project
 *
 *
 * based on ip.c, iproute.c
 *
 * Authors:
 *	Masahide NAKAMURA @USAGI
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/icmp6.h>

#include "utils.h"
#include "ip_common.h"

/* prefix flags; see kernel's net/ipv6/addrconf.c and include/net/if_inet6.h */
#define IF_PREFIX_ONLINK	0x01
#define IF_PREFIX_AUTOCONF	0x02

int print_prefix(struct nlmsghdr *n, void *arg)
{
	FILE *fp = (FILE *)arg;
	struct prefixmsg *prefix = NLMSG_DATA(n);
	int len = n->nlmsg_len;
	struct rtattr *tb[RTA_MAX+1];
	int family = preferred_family;

	if (n->nlmsg_type != RTM_NEWPREFIX) {
		fprintf(stderr, "Not a prefix: %08x %08x %08x\n",
			n->nlmsg_len, n->nlmsg_type, n->nlmsg_flags);
		return 0;
	}

	len -= NLMSG_LENGTH(sizeof(*prefix));
	if (len < 0) {
		fprintf(stderr, "BUG: wrong nlmsg len %d\n", len);
		return -1;
	}

	if (family == AF_UNSPEC)
		family = AF_INET6;
	if (family != AF_INET6)
		return 0;

	if (prefix->prefix_family != AF_INET6) {
		fprintf(stderr, "incorrect protocol family: %d\n", prefix->prefix_family);
		return 0;
	}
	if (prefix->prefix_type != ND_OPT_PREFIX_INFORMATION) {
		fprintf(stderr, "wrong ND type %d\n", prefix->prefix_type);
		return 0;
	}

	parse_rtattr(tb, RTA_MAX, RTM_RTA(prefix), len);

	if (tb[PREFIX_ADDRESS]) {
		fprintf(fp, "prefix %s/%u",
			rt_addr_n2a_rta(family, tb[PREFIX_ADDRESS]),
			prefix->prefix_len);
	}
	fprintf(fp, "dev %s ", ll_index_to_name(prefix->prefix_ifindex));

	if (prefix->prefix_flags & IF_PREFIX_ONLINK)
		fprintf(fp, "onlink ");
	if (prefix->prefix_flags & IF_PREFIX_AUTOCONF)
		fprintf(fp, "autoconf ");

	if (tb[PREFIX_CACHEINFO]) {
		const struct prefix_cacheinfo *pc
			 = RTA_DATA(tb[PREFIX_CACHEINFO]);

		fprintf(fp, "valid %u ", pc->valid_time);
		fprintf(fp, "preferred %u ", pc->preferred_time);
	}

	fprintf(fp, "\n");
	fflush(fp);

	return 0;
}