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
|
/* $OpenBSD: if_nameindex.c,v 1.9 2002/03/07 22:40:23 millert Exp $ */
/* $KAME: if_nameindex.c,v 1.7 2000/11/24 08:17:20 itojun Exp $ */
/*-
* Copyright (c) 1997, 2000
* Berkeley Software Design, Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL Berkeley Software Design, Inc. BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* BSDI Id: if_nameindex.c,v 2.3 2000/04/17 22:38:05 dab Exp
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <net/if_dl.h>
#include <net/if.h>
#include <ifaddrs.h>
#include <stdlib.h>
#include <string.h>
/*
* From RFC 2553:
*
* 4.3 Return All Interface Names and Indexes
*
* The if_nameindex structure holds the information about a single
* interface and is defined as a result of including the <net/if.h>
* header.
*
* struct if_nameindex {
* unsigned int if_index;
* char *if_name;
* };
*
* The final function returns an array of if_nameindex structures, one
* structure per interface.
*
* struct if_nameindex *if_nameindex(void);
*
* The end of the array of structures is indicated by a structure with
* an if_index of 0 and an if_name of NULL. The function returns a NULL
* pointer upon an error, and would set errno to the appropriate value.
*
* The memory used for this array of structures along with the interface
* names pointed to by the if_name members is obtained dynamically.
* This memory is freed by the next function.
*
* 4.4. Free Memory
*
* The following function frees the dynamic memory that was allocated by
* if_nameindex().
*
* #include <net/if.h>
*
* void if_freenameindex(struct if_nameindex *ptr);
*
* The argument to this function must be a pointer that was returned by
* if_nameindex().
*/
struct if_nameindex *
if_nameindex(void)
{
struct ifaddrs *ifaddrs, *ifa;
unsigned int ni;
size_t nbytes;
struct if_nameindex *ifni, *ifni2;
char *cp;
if (getifaddrs(&ifaddrs) < 0)
return(NULL);
/*
* First, find out how many interfaces there are, and how
* much space we need for the string names.
*/
ni = 0;
nbytes = 0;
for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
if (ifa->ifa_addr &&
ifa->ifa_addr->sa_family == AF_LINK) {
nbytes += strlen(ifa->ifa_name) + 1;
ni++;
}
}
/*
* Next, allocate a chunk of memory, use the first part
* for the array of structures, and the last part for
* the strings.
*/
cp = malloc((ni + 1) * sizeof(struct if_nameindex) + nbytes);
ifni = (struct if_nameindex *)cp;
if (ifni == NULL)
goto out;
cp += (ni + 1) * sizeof(struct if_nameindex);
/*
* Now just loop through the list of interfaces again,
* filling in the if_nameindex array and making copies
* of all the strings.
*/
ifni2 = ifni;
for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) {
if (ifa->ifa_addr &&
ifa->ifa_addr->sa_family == AF_LINK) {
ifni2->if_index =
((struct sockaddr_dl*)ifa->ifa_addr)->sdl_index;
ifni2->if_name = cp;
nbytes = strlen(ifa->ifa_name) + 1;
memcpy(cp, ifa->ifa_name, nbytes);
ifni2++;
cp += nbytes;
}
}
/*
* Finally, don't forget to terminate the array.
*/
ifni2->if_index = 0;
ifni2->if_name = NULL;
out:
freeifaddrs(ifaddrs);
return(ifni);
}
|
