1/* Copyright (C) 1997-2016 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
8
9 The GNU C Library 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 GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <http://www.gnu.org/licenses/>. */
17
18#include <alloca.h>
19#include <errno.h>
20#include <string.h>
21#include <stdio.h>
22#include <stdlib.h>
23#include <unistd.h>
24#include <net/if.h>
25#include <sys/socket.h>
26#include <sys/ioctl.h>
27#include <libc-lock.h>
28#include <not-cancel.h>
29
30#include "netlinkaccess.h"
31
32
33unsigned int
34__if_nametoindex (const char *ifname)
35{
36#ifndef SIOCGIFINDEX
37 __set_errno (ENOSYS);
38 return 0;
39#else
40 struct ifreq ifr;
41 int fd = __opensock ();
42
43 if (fd < 0)
44 return 0;
45
46 strncpy (ifr.ifr_name, ifname, sizeof (ifr.ifr_name));
47 if (__ioctl (fd, SIOCGIFINDEX, &ifr) < 0)
48 {
49 int saved_errno = errno;
50 close_not_cancel_no_status (fd);
51 if (saved_errno == EINVAL)
52 __set_errno (ENOSYS);
53 return 0;
54 }
55 close_not_cancel_no_status (fd);
56 return ifr.ifr_ifindex;
57#endif
58}
59libc_hidden_def (__if_nametoindex)
60weak_alias (__if_nametoindex, if_nametoindex)
61libc_hidden_weak (if_nametoindex)
62
63
64void
65__if_freenameindex (struct if_nameindex *ifn)
66{
67 struct if_nameindex *ptr = ifn;
68 while (ptr->if_name || ptr->if_index)
69 {
70 free (ptr->if_name);
71 ++ptr;
72 }
73 free (ifn);
74}
75libc_hidden_def (__if_freenameindex)
76weak_alias (__if_freenameindex, if_freenameindex)
77libc_hidden_weak (if_freenameindex)
78
79
80static struct if_nameindex *
81if_nameindex_netlink (void)
82{
83 struct netlink_handle nh = { 0, 0, 0, NULL, NULL };
84 struct if_nameindex *idx = NULL;
85
86 if (__netlink_open (&nh) < 0)
87 return NULL;
88
89
90 /* Tell the kernel that we wish to get a list of all
91 active interfaces. Collect all data for every interface. */
92 if (__netlink_request (&nh, RTM_GETLINK) < 0)
93 goto exit_free;
94
95 /* Count the interfaces. */
96 unsigned int nifs = 0;
97 for (struct netlink_res *nlp = nh.nlm_list; nlp; nlp = nlp->next)
98 {
99 struct nlmsghdr *nlh;
100 size_t size = nlp->size;
101
102 if (nlp->nlh == NULL)
103 continue;
104
105 /* Walk through all entries we got from the kernel and look, which
106 message type they contain. */
107 for (nlh = nlp->nlh; NLMSG_OK (nlh, size); nlh = NLMSG_NEXT (nlh, size))
108 {
109 /* Check if the message is what we want. */
110 if ((pid_t) nlh->nlmsg_pid != nh.pid || nlh->nlmsg_seq != nlp->seq)
111 continue;
112
113 if (nlh->nlmsg_type == NLMSG_DONE)
114 break; /* ok */
115
116 if (nlh->nlmsg_type == RTM_NEWLINK)
117 ++nifs;
118 }
119 }
120
121 idx = malloc ((nifs + 1) * sizeof (struct if_nameindex));
122 if (idx == NULL)
123 {
124 nomem:
125 __set_errno (ENOBUFS);
126 goto exit_free;
127 }
128
129 /* Add the interfaces. */
130 nifs = 0;
131 for (struct netlink_res *nlp = nh.nlm_list; nlp; nlp = nlp->next)
132 {
133 struct nlmsghdr *nlh;
134 size_t size = nlp->size;
135
136 if (nlp->nlh == NULL)
137 continue;
138
139 /* Walk through all entries we got from the kernel and look, which
140 message type they contain. */
141 for (nlh = nlp->nlh; NLMSG_OK (nlh, size); nlh = NLMSG_NEXT (nlh, size))
142 {
143 /* Check if the message is what we want. */
144 if ((pid_t) nlh->nlmsg_pid != nh.pid || nlh->nlmsg_seq != nlp->seq)
145 continue;
146
147 if (nlh->nlmsg_type == NLMSG_DONE)
148 break; /* ok */
149
150 if (nlh->nlmsg_type == RTM_NEWLINK)
151 {
152 struct ifinfomsg *ifim = (struct ifinfomsg *) NLMSG_DATA (nlh);
153 struct rtattr *rta = IFLA_RTA (ifim);
154 size_t rtasize = IFLA_PAYLOAD (nlh);
155
156 idx[nifs].if_index = ifim->ifi_index;
157
158 while (RTA_OK (rta, rtasize))
159 {
160 char *rta_data = RTA_DATA (rta);
161 size_t rta_payload = RTA_PAYLOAD (rta);
162
163 if (rta->rta_type == IFLA_IFNAME)
164 {
165 idx[nifs].if_name = __strndup (rta_data, rta_payload);
166 if (idx[nifs].if_name == NULL)
167 {
168 idx[nifs].if_index = 0;
169 __if_freenameindex (idx);
170 idx = NULL;
171 goto nomem;
172 }
173 break;
174 }
175
176 rta = RTA_NEXT (rta, rtasize);
177 }
178
179 ++nifs;
180 }
181 }
182 }
183
184 idx[nifs].if_index = 0;
185 idx[nifs].if_name = NULL;
186
187 exit_free:
188 __netlink_free_handle (&nh);
189 __netlink_close (&nh);
190
191 return idx;
192}
193
194
195struct if_nameindex *
196__if_nameindex (void)
197{
198#ifndef SIOCGIFINDEX
199 __set_errno (ENOSYS);
200 return NULL;
201#else
202 struct if_nameindex *result = if_nameindex_netlink ();
203 return result;
204#endif
205}
206weak_alias (__if_nameindex, if_nameindex)
207libc_hidden_weak (if_nameindex)
208
209
210char *
211__if_indextoname (unsigned int ifindex, char *ifname)
212{
213 /* We may be able to do the conversion directly, rather than searching a
214 list. This ioctl is not present in kernels before version 2.1.50. */
215 struct ifreq ifr;
216 int fd;
217 int status;
218
219 fd = __opensock ();
220
221 if (fd < 0)
222 return NULL;
223
224 ifr.ifr_ifindex = ifindex;
225 status = __ioctl (fd, SIOCGIFNAME, &ifr);
226
227 close_not_cancel_no_status (fd);
228
229 if (status < 0)
230 {
231 if (errno == ENODEV)
232 /* POSIX requires ENXIO. */
233 __set_errno (ENXIO);
234
235 return NULL;
236 }
237 else
238 return strncpy (ifname, ifr.ifr_name, IFNAMSIZ);
239}
240weak_alias (__if_indextoname, if_indextoname)
241libc_hidden_weak (if_indextoname)
242