1 /*
2 * Copyright (c) 2017 Petr Vorel <pvorel@suse.cz>
3 *
4 * This program is free software: you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation, either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program. If not, see <http://www.gnu.org/licenses/>.
16 */
17
18 #include <sys/socket.h>
19 #include <linux/rtnetlink.h>
20 #include <net/if.h>
21 #include <stdio.h>
22 #include <stdlib.h>
23
24 #define TST_NO_DEFAULT_MAIN
25 #include "tst_test.h"
26
27 #include "tst_net.h"
28
29 static char *iface;
30 static int prefix;
31
usage(const char * cmd)32 static void usage(const char *cmd)
33 {
34 fprintf(stderr, "USAGE:\n"
35 "%s IP_LHOST[/PREFIX]\n"
36 "%s -r IP_RHOST[/PREFIX]\n"
37 "%s -h\n\n"
38 "Set prefix and interface name for given IP.\n"
39 "Prefix and interface are found from kernel exported info (rtnetlink).\n\n"
40 "EXPORTED VARIABLES:\n"
41 "Export one of the following variables:\n"
42 "IPV4_LPREFIX: IPv4 prefix for IPV4_LNETWORK\n"
43 "IPV4_RPREFIX: IPv4 prefix for IPV4_RNETWORK\n"
44 "IPV6_LPREFIX: IPv6 prefix for IPV6_LNETWORK\n"
45 "IPV6_RPREFIX: IPv6 prefix for IPV6_RNETWORK\n"
46 "Export one of the following variables (if found):\n"
47 "LHOST_IFACES: iface name of the local host\n"
48 "RHOST_IFACES: iface name of the remote host\n\n"
49 "PARAMS:\n"
50 "-h this help\n"
51 "-r export remote environment variables\n",
52 cmd, cmd, cmd);
53 }
54
read_iface_prefix(const char * ip_str,int is_ipv6)55 static int read_iface_prefix(const char *ip_str, int is_ipv6)
56 {
57 uint8_t family = is_ipv6 ? AF_INET6 : AF_INET;
58
59 char buf[16384];
60 unsigned int len;
61
62 struct {
63 struct nlmsghdr nlhdr;
64 struct ifaddrmsg addrmsg;
65 } msg;
66
67 struct nlmsghdr *retmsg;
68
69 int sock = SAFE_SOCKET(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
70
71 memset(&msg, 0, sizeof(msg));
72 msg.nlhdr.nlmsg_len = NLMSG_LENGTH(sizeof(struct ifaddrmsg));
73 msg.nlhdr.nlmsg_flags = NLM_F_REQUEST | NLM_F_ROOT;
74 msg.nlhdr.nlmsg_type = RTM_GETADDR;
75 msg.addrmsg.ifa_family = family;
76
77 SAFE_SEND(1, sock, &msg, msg.nlhdr.nlmsg_len, 0);
78 len = recv(sock, buf, sizeof(buf), 0);
79 retmsg = (struct nlmsghdr *)buf;
80
81 while NLMSG_OK(retmsg, len) {
82 char ifname[IFNAMSIZ];
83 struct ifaddrmsg *retaddr;
84 struct rtattr *retrta;
85 char pradd[128];
86 int attlen;
87
88 retaddr = (struct ifaddrmsg *)NLMSG_DATA(retmsg);
89 retrta = (struct rtattr *)IFA_RTA(retaddr);
90 attlen = IFA_PAYLOAD(retmsg);
91
92 while RTA_OK(retrta, attlen) {
93 if (retrta->rta_type == IFA_ADDRESS) {
94 inet_ntop(family, RTA_DATA(retrta), pradd,
95 sizeof(pradd));
96
97 if_indextoname(retaddr->ifa_index, ifname);
98
99 if (!strcmp(pradd, ip_str)) {
100 prefix = retaddr->ifa_prefixlen;
101 iface = strdup(ifname);
102 return 0;
103 }
104 }
105 retrta = RTA_NEXT(retrta, attlen);
106 }
107 retmsg = NLMSG_NEXT(retmsg, len);
108 }
109
110 return -1;
111 }
112
print_ivar(const char * name,unsigned int val)113 static void print_ivar(const char *name, unsigned int val)
114 {
115 printf("export %s=%d\n", name, val);
116 }
117
main(int argc,char * argv[])118 int main(int argc, char *argv[])
119 {
120 char *ip_str = NULL, *prefix_str = NULL;
121 int is_ipv6, is_rhost = 0;
122 struct in_addr ip;
123 struct in6_addr ip6;
124
125 int is_usage = argc > 1 && (!strcmp(argv[1], "-h") ||
126 !strcmp(argv[1], "--help"));
127 if (argc < 2 || is_usage) {
128 usage(argv[0]);
129 exit(is_usage ? EXIT_SUCCESS : EXIT_FAILURE);
130 }
131 if (!strcmp(argv[1], "-r"))
132 is_rhost = 1;
133
134 ip_str = argv[is_rhost ? 2 : 1];
135 is_ipv6 = !!strchr(ip_str, ':');
136
137 prefix_str = strchr(ip_str, '/');
138 if (prefix_str) {
139 prefix = get_prefix(ip_str, is_ipv6);
140 tst_res_comment(TINFO,
141 "IP address '%s' contains prefix %d, using it and don't search for iface.\n",
142 ip_str, prefix);
143 } else if (read_iface_prefix(ip_str, is_ipv6)) {
144 tst_res_comment(TINFO,
145 "prefix and interface not found for '%s'.\n", ip_str);
146 exit(EXIT_SUCCESS);
147 }
148
149 /* checks for validity of IP string */
150 if (is_ipv6)
151 get_in6_addr(ip_str, &ip6);
152 else
153 get_in_addr(ip_str, &ip);
154
155 print_svar_change(is_rhost ? "RHOST_IFACES" : "LHOST_IFACES", iface);
156 if (is_ipv6)
157 print_ivar(is_rhost ? "IPV6_RPREFIX" : "IPV6_LPREFIX", prefix);
158 else
159 print_ivar(is_rhost ? "IPV4_RPREFIX" : "IPV4_LPREFIX", prefix);
160
161 exit(EXIT_SUCCESS);
162 }
163