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
|
/* getifaddrs -- get names and addresses of all network interfaces
Copyright (C) 2002 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 <ifaddrs.h>
#include <net/if.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <netinet/in.h>
#include "ifreq.h"
/* Create a linked list of `struct ifaddrs' structures, one for each
network interface on the host machine. If successful, store the
list in *IFAP and return 0. On errors, return -1 and set `errno'. */
int
getifaddrs (struct ifaddrs **ifap)
{
/* This implementation handles only IPv4 interfaces.
The various ioctls below will only work on an AF_INET socket.
Some different mechanism entirely must be used for IPv6. */
int fd = __socket (AF_INET, SOCK_DGRAM, 0);
struct ifreq *ifreqs;
int nifs, i;
if (fd < 0)
return -1;
__ifreq (&ifreqs, &nifs, fd);
if (ifreqs == NULL) /* XXX doesn't distinguish error vs none */
{
__close (fd);
return -1;
}
/* Now we have the list of interfaces and each one's address.
Put it into the expected format and fill in the remaining details. */
if (nifs == 0)
*ifap = NULL;
else
{
struct
{
struct ifaddrs ia;
struct sockaddr addr, netmask, broadaddr;
char name[IF_NAMESIZE];
} *storage;
storage = malloc (nifs * sizeof storage[0]);
if (storage == NULL)
{
__close (fd);
__if_freereq (ifreqs, nifs);
return -1;
}
i = 0;
do
{
struct ifreq *const ifr = &ifreqs[i];
/* Fill in all pointers to the storage we've already allocated. */
storage[i].ia.ifa_next = &storage[i + 1].ia;
storage[i].ia.ifa_addr = &storage[i].addr;
storage[i].ia.ifa_netmask = &storage[i].netmask;
storage[i].ia.ifa_broadaddr = &storage[i].broadaddr; /* & dstaddr */
/* Now copy the information we already have from SIOCGIFCONF. */
storage[i].ia.ifa_name = strncpy (storage[i].name, ifr->ifr_name,
sizeof storage[i].name);
storage[i].addr = ifr->ifr_addr;
/* The SIOCGIFCONF call filled in only the name and address.
Now we must also ask for the other information we need. */
if (__ioctl (fd, SIOCGIFFLAGS, ifr) < 0)
break;
storage[i].ia.ifa_flags = ifr->ifr_flags;
ifr->ifr_addr = storage[i].addr;
if (__ioctl (fd, SIOCGIFNETMASK, ifr) < 0)
break;
storage[i].netmask = ifr->ifr_netmask;
if (ifr->ifr_flags & IFF_BROADCAST)
{
ifr->ifr_addr = storage[i].addr;
if (__ioctl (fd, SIOCGIFBRDADDR, ifr) < 0)
break;
storage[i].broadaddr = ifr->ifr_broadaddr;
}
else if (ifr->ifr_flags & IFF_POINTOPOINT)
{
ifr->ifr_addr = storage[i].addr;
if (__ioctl (fd, SIOCGIFDSTADDR, ifr) < 0)
break;
storage[i].broadaddr = ifr->ifr_dstaddr;
}
else
/* Just 'cause. */
memset (&storage[i].broadaddr, 0, sizeof storage[i].broadaddr);
storage[i].ia.ifa_data = NULL; /* Nothing here for now. */
} while (++i < nifs);
if (i < nifs) /* Broke out early on error. */
{
__close (fd);
free (storage);
__if_freereq (ifreqs, nifs);
return -1;
}
storage[i - 1].ia.ifa_next = NULL;
*ifap = &storage[0].ia;
__close (fd);
__if_freereq (ifreqs, nifs);
}
return 0;
}
void
freeifaddrs (struct ifaddrs *ifa)
{
free (ifa);
}
|
