/*
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* Copyright (c) 2017 Petr Vorel <pvorel@suse.cz>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <sys/socket.h>
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#include <linux/rtnetlink.h>
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#include <net/if.h>
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#include <stdio.h>
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#include <stdlib.h>
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#define TST_NO_DEFAULT_MAIN
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#include "tst_test.h"
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#include "tst_net.h"
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static char *iface;
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static int prefix;
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static void usage(const char *cmd)
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{
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fprintf(stderr, "USAGE:\n"
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"%s IP_LHOST[/PREFIX]\n"
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"%s -r IP_RHOST[/PREFIX]\n"
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"%s -h\n\n"
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"Set prefix and interface name for given IP.\n"
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"Prefix and interface are found from kernel exported info (rtnetlink).\n\n"
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"EXPORTED VARIABLES:\n"
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"Export one of the following variables:\n"
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"IPV4_LPREFIX: IPv4 prefix for IPV4_LNETWORK\n"
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"IPV4_RPREFIX: IPv4 prefix for IPV4_RNETWORK\n"
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"IPV6_LPREFIX: IPv6 prefix for IPV6_LNETWORK\n"
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"IPV6_RPREFIX: IPv6 prefix for IPV6_RNETWORK\n"
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"Export one of the following variables (if found):\n"
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"LHOST_IFACES: iface name of the local host\n"
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"RHOST_IFACES: iface name of the remote host\n\n"
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"PARAMS:\n"
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"-h this help\n"
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"-r export remote environment variables\n",
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cmd, cmd, cmd);
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}
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static int read_iface_prefix(const char *ip_str, int is_ipv6)
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{
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uint8_t family = is_ipv6 ? AF_INET6 : AF_INET;
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char buf[16384];
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unsigned int len;
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struct {
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struct nlmsghdr nlhdr;
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struct ifaddrmsg addrmsg;
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} msg;
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struct nlmsghdr *retmsg;
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int sock = SAFE_SOCKET(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
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memset(&msg, 0, sizeof(msg));
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msg.nlhdr.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
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msg.nlhdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT;
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msg.nlhdr.nlmsg_type = RTM_GETADDR;
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msg.addrmsg.ifa_family = family;
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SAFE_SEND(1, sock, &msg, msg.nlhdr.nlmsg_len, 0);
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len = recv(sock, buf, sizeof(buf), 0);
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retmsg = (struct nlmsghdr *)buf;
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while NLMSG_OK(retmsg, len) {
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char ifname[IFNAMSIZ];
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struct ifaddrmsg *retaddr;
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struct rtattr *retrta;
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char pradd[128];
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int attlen;
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retaddr = (struct ifaddrmsg *)NLMSG_DATA(retmsg);
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retrta = (struct rtattr *)IFA_RTA(retaddr);
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attlen = IFA_PAYLOAD(retmsg);
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while RTA_OK(retrta, attlen) {
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if (retrta->rta_type == IFA_ADDRESS) {
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inet_ntop(family, RTA_DATA(retrta), pradd,
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sizeof(pradd));
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if_indextoname(retaddr->ifa_index, ifname);
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if (!strcmp(pradd, ip_str)) {
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prefix = retaddr->ifa_prefixlen;
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iface = strdup(ifname);
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return 0;
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}
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}
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retrta = RTA_NEXT(retrta, attlen);
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}
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retmsg = NLMSG_NEXT(retmsg, len);
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}
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return -1;
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}
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static void print_ivar(const char *name, unsigned int val)
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{
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printf("export %s=%d\n", name, val);
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}
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int main(int argc, char *argv[])
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{
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char *ip_str = NULL, *prefix_str = NULL;
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int is_ipv6, is_rhost = 0;
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struct in_addr ip;
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struct in6_addr ip6;
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int is_usage = argc > 1 && (!strcmp(argv[1], "-h") ||
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!strcmp(argv[1], "--help"));
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if (argc < 2 || is_usage) {
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usage(argv[0]);
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exit(is_usage ? EXIT_SUCCESS : EXIT_FAILURE);
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}
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if (!strcmp(argv[1], "-r"))
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is_rhost = 1;
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ip_str = argv[is_rhost ? 2 : 1];
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is_ipv6 = !!strchr(ip_str, ':');
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prefix_str = strchr(ip_str, '/');
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if (prefix_str) {
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prefix = get_prefix(ip_str, is_ipv6);
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tst_res_comment(TINFO,
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"IP address '%s' contains prefix %d, using it and don't search for iface.\n",
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ip_str, prefix);
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} else if (read_iface_prefix(ip_str, is_ipv6)) {
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tst_res_comment(TINFO,
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"prefix and interface not found for '%s'.\n", ip_str);
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exit(EXIT_SUCCESS);
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}
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/* checks for validity of IP string */
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if (is_ipv6)
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get_in6_addr(ip_str, &ip6);
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else
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get_in_addr(ip_str, &ip);
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print_svar_change(is_rhost ? "RHOST_IFACES" : "LHOST_IFACES", iface);
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if (is_ipv6)
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print_ivar(is_rhost ? "IPV6_RPREFIX" : "IPV6_LPREFIX", prefix);
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else
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print_ivar(is_rhost ? "IPV4_RPREFIX" : "IPV4_LPREFIX", prefix);
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exit(EXIT_SUCCESS);
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}
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