1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
|
/* Copyright (C) 1997-2021 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <alloca.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <net/if.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <libc-lock.h>
#include <not-cancel.h>
#include "netlinkaccess.h"
unsigned int
__if_nametoindex (const char *ifname)
{
#ifndef SIOCGIFINDEX
__set_errno (ENOSYS);
return 0;
#else
struct ifreq ifr;
if (strlen (ifname) >= IFNAMSIZ)
{
__set_errno (ENODEV);
return 0;
}
strncpy (ifr.ifr_name, ifname, sizeof (ifr.ifr_name));
int fd = __opensock ();
if (fd < 0)
return 0;
if (__ioctl (fd, SIOCGIFINDEX, &ifr) < 0)
{
int saved_errno = errno;
__close_nocancel_nostatus (fd);
if (saved_errno == EINVAL)
__set_errno (ENOSYS);
return 0;
}
__close_nocancel_nostatus (fd);
return ifr.ifr_ifindex;
#endif
}
libc_hidden_def (__if_nametoindex)
weak_alias (__if_nametoindex, if_nametoindex)
libc_hidden_weak (if_nametoindex)
void
__if_freenameindex (struct if_nameindex *ifn)
{
struct if_nameindex *ptr = ifn;
while (ptr->if_name || ptr->if_index)
{
free (ptr->if_name);
++ptr;
}
free (ifn);
}
libc_hidden_def (__if_freenameindex)
weak_alias (__if_freenameindex, if_freenameindex)
libc_hidden_weak (if_freenameindex)
static struct if_nameindex *
if_nameindex_netlink (void)
{
struct netlink_handle nh = { 0, 0, 0, NULL, NULL };
struct if_nameindex *idx = NULL;
if (__netlink_open (&nh) < 0)
return NULL;
/* Tell the kernel that we wish to get a list of all
active interfaces. Collect all data for every interface. */
if (__netlink_request (&nh, RTM_GETLINK) < 0)
goto exit_free;
/* Count the interfaces. */
unsigned int nifs = 0;
for (struct netlink_res *nlp = nh.nlm_list; nlp; nlp = nlp->next)
{
struct nlmsghdr *nlh;
size_t size = nlp->size;
if (nlp->nlh == NULL)
continue;
/* Walk through all entries we got from the kernel and look, which
message type they contain. */
for (nlh = nlp->nlh; NLMSG_OK (nlh, size); nlh = NLMSG_NEXT (nlh, size))
{
/* Check if the message is what we want. */
if ((pid_t) nlh->nlmsg_pid != nh.pid || nlh->nlmsg_seq != nlp->seq)
continue;
if (nlh->nlmsg_type == NLMSG_DONE)
break; /* ok */
if (nlh->nlmsg_type == RTM_NEWLINK)
++nifs;
}
}
idx = malloc ((nifs + 1) * sizeof (struct if_nameindex));
if (idx == NULL)
{
nomem:
__set_errno (ENOBUFS);
goto exit_free;
}
/* Add the interfaces. */
nifs = 0;
for (struct netlink_res *nlp = nh.nlm_list; nlp; nlp = nlp->next)
{
struct nlmsghdr *nlh;
size_t size = nlp->size;
if (nlp->nlh == NULL)
continue;
/* Walk through all entries we got from the kernel and look, which
message type they contain. */
for (nlh = nlp->nlh; NLMSG_OK (nlh, size); nlh = NLMSG_NEXT (nlh, size))
{
/* Check if the message is what we want. */
if ((pid_t) nlh->nlmsg_pid != nh.pid || nlh->nlmsg_seq != nlp->seq)
continue;
if (nlh->nlmsg_type == NLMSG_DONE)
break; /* ok */
if (nlh->nlmsg_type == RTM_NEWLINK)
{
struct ifinfomsg *ifim = (struct ifinfomsg *) NLMSG_DATA (nlh);
struct rtattr *rta = IFLA_RTA (ifim);
size_t rtasize = IFLA_PAYLOAD (nlh);
idx[nifs].if_index = ifim->ifi_index;
while (RTA_OK (rta, rtasize))
{
char *rta_data = RTA_DATA (rta);
size_t rta_payload = RTA_PAYLOAD (rta);
if (rta->rta_type == IFLA_IFNAME)
{
idx[nifs].if_name = __strndup (rta_data, rta_payload);
if (idx[nifs].if_name == NULL)
{
idx[nifs].if_index = 0;
__if_freenameindex (idx);
idx = NULL;
goto nomem;
}
break;
}
rta = RTA_NEXT (rta, rtasize);
}
++nifs;
}
}
}
idx[nifs].if_index = 0;
idx[nifs].if_name = NULL;
exit_free:
__netlink_free_handle (&nh);
__netlink_close (&nh);
return idx;
}
struct if_nameindex *
__if_nameindex (void)
{
#ifndef SIOCGIFINDEX
__set_errno (ENOSYS);
return NULL;
#else
struct if_nameindex *result = if_nameindex_netlink ();
return result;
#endif
}
weak_alias (__if_nameindex, if_nameindex)
libc_hidden_weak (if_nameindex)
char *
__if_indextoname (unsigned int ifindex, char ifname[IF_NAMESIZE])
{
/* We may be able to do the conversion directly, rather than searching a
list. This ioctl is not present in kernels before version 2.1.50. */
struct ifreq ifr;
int fd;
int status;
fd = __opensock ();
if (fd < 0)
return NULL;
ifr.ifr_ifindex = ifindex;
status = __ioctl (fd, SIOCGIFNAME, &ifr);
__close_nocancel_nostatus (fd);
if (status < 0)
{
if (errno == ENODEV)
/* POSIX requires ENXIO. */
__set_errno (ENXIO);
return NULL;
}
else
return strncpy (ifname, ifr.ifr_name, IFNAMSIZ);
}
weak_alias (__if_indextoname, if_indextoname)
libc_hidden_weak (if_indextoname)
|
