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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (c) 2017 Petr Vorel <pvorel@suse.cz>
*/
#include <sys/socket.h>
#include <linux/rtnetlink.h>
#include <net/if.h>
#include <stdio.h>
#include <stdlib.h>
#define TST_NO_DEFAULT_MAIN
#include "tst_test.h"
#include "tst_net.h"
static char *iface;
static int prefix;
static void usage(const char *cmd)
{
fprintf(stderr, "USAGE:\n"
"%s IP_LHOST[/PREFIX]\n"
"%s -r IP_RHOST[/PREFIX]\n"
"%s -h\n\n"
"Set prefix and interface name for given IP.\n"
"Prefix and interface are found from kernel exported info (rtnetlink).\n\n"
"EXPORTED VARIABLES:\n"
"Export one of the following variables:\n"
"IPV4_LPREFIX: IPv4 prefix for IPV4_LNETWORK\n"
"IPV4_RPREFIX: IPv4 prefix for IPV4_RNETWORK\n"
"IPV6_LPREFIX: IPv6 prefix for IPV6_LNETWORK\n"
"IPV6_RPREFIX: IPv6 prefix for IPV6_RNETWORK\n"
"Export one of the following variables (if found):\n"
"LHOST_IFACES: iface name of the local host\n"
"RHOST_IFACES: iface name of the remote host\n\n"
"PARAMS:\n"
"-h this help\n"
"-r export remote environment variables\n",
cmd, cmd, cmd);
}
static int read_iface_prefix(const char *ip_str, int is_ipv6)
{
uint8_t family = is_ipv6 ? AF_INET6 : AF_INET;
char buf[16384];
unsigned int len;
struct {
struct nlmsghdr nlhdr;
struct ifaddrmsg addrmsg;
} msg;
struct nlmsghdr *retmsg;
int sock = SAFE_SOCKET(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
memset(&msg, 0, sizeof(msg));
msg.nlhdr.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
msg.nlhdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT;
msg.nlhdr.nlmsg_type = RTM_GETADDR;
msg.addrmsg.ifa_family = family;
SAFE_SEND(1, sock, &msg, msg.nlhdr.nlmsg_len, 0);
len = recv(sock, buf, sizeof(buf), 0);
retmsg = (struct nlmsghdr *)buf;
while NLMSG_OK(retmsg, len) {
char ifname[IFNAMSIZ];
struct ifaddrmsg *retaddr;
struct rtattr *retrta;
char pradd[128];
int attlen;
retaddr = (struct ifaddrmsg *)NLMSG_DATA(retmsg);
retrta = (struct rtattr *)IFA_RTA(retaddr);
attlen = IFA_PAYLOAD(retmsg);
while RTA_OK(retrta, attlen) {
if (retrta->rta_type == IFA_ADDRESS) {
inet_ntop(family, RTA_DATA(retrta), pradd,
sizeof(pradd));
if_indextoname(retaddr->ifa_index, ifname);
if (!strcmp(pradd, ip_str)) {
prefix = retaddr->ifa_prefixlen;
iface = strdup(ifname);
return 0;
}
}
retrta = RTA_NEXT(retrta, attlen);
}
retmsg = NLMSG_NEXT(retmsg, len);
}
return -1;
}
static void print_ivar(const char *name, unsigned int val)
{
printf("export %s=%d\n", name, val);
}
int main(int argc, char *argv[])
{
char *ip_str = NULL, *prefix_str = NULL;
int is_ipv6, is_rhost = 0;
struct in_addr ip;
struct in6_addr ip6;
int is_usage = argc > 1 && (!strcmp(argv[1], "-h") ||
!strcmp(argv[1], "--help"));
if (argc < 2 || is_usage) {
usage(argv[0]);
exit(is_usage ? EXIT_SUCCESS : EXIT_FAILURE);
}
if (!strcmp(argv[1], "-r"))
is_rhost = 1;
ip_str = argv[is_rhost ? 2 : 1];
is_ipv6 = !!strchr(ip_str, ':');
prefix_str = strchr(ip_str, '/');
if (prefix_str) {
prefix = get_prefix(ip_str, is_ipv6);
tst_res_comment(TINFO,
"IP address '%s' contains prefix %d, using it and don't search for iface.\n",
ip_str, prefix);
} else if (read_iface_prefix(ip_str, is_ipv6)) {
tst_res_comment(TINFO,
"prefix and interface not found for '%s'.\n", ip_str);
exit(EXIT_SUCCESS);
}
/* checks for validity of IP string */
if (is_ipv6)
get_in6_addr(ip_str, &ip6);
else
get_in_addr(ip_str, &ip);
print_svar_change(is_rhost ? "RHOST_IFACES" : "LHOST_IFACES", iface);
if (is_ipv6)
print_ivar(is_rhost ? "IPV6_RPREFIX" : "IPV6_LPREFIX", prefix);
else
print_ivar(is_rhost ? "IPV4_RPREFIX" : "IPV4_LPREFIX", prefix);
exit(EXIT_SUCCESS);
}