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 | |
33 | unsigned 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 | } |
59 | libc_hidden_def (__if_nametoindex) |
60 | weak_alias (__if_nametoindex, if_nametoindex) |
61 | libc_hidden_weak (if_nametoindex) |
62 | |
63 | |
64 | void |
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 | } |
75 | libc_hidden_def (__if_freenameindex) |
76 | weak_alias (__if_freenameindex, if_freenameindex) |
77 | libc_hidden_weak (if_freenameindex) |
78 | |
79 | |
80 | static struct if_nameindex * |
81 | if_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 | |
195 | struct 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 | } |
206 | weak_alias (__if_nameindex, if_nameindex) |
207 | libc_hidden_weak (if_nameindex) |
208 | |
209 | |
210 | char * |
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 | } |
240 | weak_alias (__if_indextoname, if_indextoname) |
241 | libc_hidden_weak (if_indextoname) |
242 | |