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
|
/* Determine protocol families for which interfaces exist. Linux version.
Copyright (C) 2003 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, write to the Free
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
02111-1307 USA. */
#include <errno.h>
#include <ifaddrs.h>
#include <netdb.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <sys/socket.h>
#include <asm/types.h>
#include <linux/netlink.h>
#include <linux/rtnetlink.h>
#include "kernel-features.h"
static int
make_request (int fd, pid_t pid, bool *seen_ipv4, bool *seen_ipv6)
{
struct
{
struct nlmsghdr nlh;
struct rtgenmsg g;
} req;
struct sockaddr_nl nladdr;
req.nlh.nlmsg_len = sizeof (req);
req.nlh.nlmsg_type = RTM_GETADDR;
req.nlh.nlmsg_flags = NLM_F_ROOT | NLM_F_MATCH | NLM_F_REQUEST;
req.nlh.nlmsg_pid = 0;
req.nlh.nlmsg_seq = time (NULL);
req.g.rtgen_family = AF_UNSPEC;
memset (&nladdr, '\0', sizeof (nladdr));
nladdr.nl_family = AF_NETLINK;
if (TEMP_FAILURE_RETRY (__sendto (fd, (void *) &req, sizeof (req), 0,
(struct sockaddr *) &nladdr,
sizeof (nladdr))) < 0)
return -1;
*seen_ipv4 = false;
*seen_ipv6 = false;
bool done = false;
char buf[4096];
struct iovec iov = { buf, sizeof (buf) };
do
{
struct msghdr msg =
{
(void *) &nladdr, sizeof (nladdr),
&iov, 1,
NULL, 0,
0
};
ssize_t read_len = TEMP_FAILURE_RETRY (__recvmsg (fd, &msg, 0));
if (read_len < 0)
return -1;
if (msg.msg_flags & MSG_TRUNC)
return -1;
struct nlmsghdr *nlmh;
for (nlmh = (struct nlmsghdr *) buf;
NLMSG_OK (nlmh, (size_t) read_len);
nlmh = (struct nlmsghdr *) NLMSG_NEXT (nlmh, read_len))
{
if ((pid_t) nlmh->nlmsg_pid != pid
|| nlmh->nlmsg_seq != req.nlh.nlmsg_seq)
continue;
if (nlmh->nlmsg_type == RTM_NEWADDR)
{
struct ifaddrmsg *ifam = (struct ifaddrmsg *) NLMSG_DATA (nlmh);
switch (ifam->ifa_family)
{
case AF_INET:
*seen_ipv4 = true;
break;
case AF_INET6:
*seen_ipv6 = true;
break;
default:
/* Ignore. */
break;
}
}
else if (nlmh->nlmsg_type == NLMSG_DONE)
/* We found the end, leave the loop. */
done = true;
else ;
}
}
while (! done);
__close (fd);
return 0;
}
/* We don't know if we have NETLINK support compiled in in our
Kernel. */
#if __ASSUME_NETLINK_SUPPORT == 0
/* Define in ifaddrs.h. */
extern int __no_netlink_support attribute_hidden;
#else
# define __no_netlink_support 0
#endif
void
attribute_hidden
__check_pf (bool *seen_ipv4, bool *seen_ipv6)
{
if (! __no_netlink_support)
{
int fd = __socket (PF_NETLINK, SOCK_RAW, NETLINK_ROUTE);
struct sockaddr_nl nladdr;
memset (&nladdr, '\0', sizeof (nladdr));
nladdr.nl_family = AF_NETLINK;
socklen_t addr_len = sizeof (nladdr);
if (fd >= 0
&& __bind (fd, (struct sockaddr *) &nladdr, sizeof (nladdr)) == 0
&& __getsockname (fd, (struct sockaddr *) &nladdr, &addr_len) == 0
&& make_request (fd, nladdr.nl_pid, seen_ipv4, seen_ipv6) == 0)
/* It worked. */
return;
if (fd >= 0)
__close (fd);
#if __ASSUME_NETLINK_SUPPORT == 0
/* Remember that there is no netlink support. */
__no_netlink_support = 1;
#else
/* We cannot determine what interfaces are available. Be
pessimistic. */
*seen_ipv4 = true;
*seen_ipv6 = true;
#endif
}
#if __ASSUME_NETLINK_SUPPORT == 0
/* No netlink. Get the interface list via getifaddrs. */
struct ifaddrs *ifa = NULL;
if (getifaddrs (&ifa) != 0)
{
/* We cannot determine what interfaces are available. Be
pessimistic. */
*seen_ipv4 = true;
*seen_ipv6 = true;
return;
}
*seen_ipv4 = false;
*seen_ipv6 = false;
struct ifaddrs *runp;
for (runp = ifa; runp != NULL; runp = runp->ifa_next)
if (runp->ifa_addr->sa_family == PF_INET)
*seen_ipv4 = true;
else if (runp->ifa_addr->sa_family == PF_INET6)
*seen_ipv6 = true;
(void) freeifaddrs (ifa);
#endif
}
|
