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760c99e3 | 1 | /* |
760c99e3 JSP |
2 | * Copyright (c) 1990 Jan-Simon Pendry |
3 | * Copyright (c) 1990 Imperial College of Science, Technology & Medicine | |
4 | * Copyright (c) 1990 The Regents of the University of California. | |
5 | * All rights reserved. | |
6 | * | |
7 | * This code is derived from software contributed to Berkeley by | |
8 | * Jan-Simon Pendry at Imperial College, London. | |
9 | * | |
af359dea C |
10 | * Redistribution and use in source and binary forms, with or without |
11 | * modification, are permitted provided that the following conditions | |
12 | * are met: | |
13 | * 1. Redistributions of source code must retain the above copyright | |
14 | * notice, this list of conditions and the following disclaimer. | |
15 | * 2. Redistributions in binary form must reproduce the above copyright | |
16 | * notice, this list of conditions and the following disclaimer in the | |
17 | * documentation and/or other materials provided with the distribution. | |
18 | * 3. All advertising materials mentioning features or use of this software | |
19 | * must display the following acknowledgement: | |
20 | * This product includes software developed by the University of | |
21 | * California, Berkeley and its contributors. | |
22 | * 4. Neither the name of the University nor the names of its contributors | |
23 | * may be used to endorse or promote products derived from this software | |
24 | * without specific prior written permission. | |
25 | * | |
26 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
27 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
28 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
29 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
30 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
31 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
32 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
33 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
34 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
35 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
36 | * SUCH DAMAGE. | |
37 | * | |
38 | * @(#)wire.c 5.3 (Berkeley) 5/12/91 | |
39 | * | |
40 | * $Id: wire.c,v 5.2.1.5 91/05/07 22:14:21 jsp Alpha $ | |
760c99e3 | 41 | * |
760c99e3 JSP |
42 | */ |
43 | ||
44 | /* | |
45 | * This routine returns the subnet (address&netmask) for the primary network | |
46 | * interface. If the resulting address has an entry in the hosts file, the | |
47 | * corresponding name is retuned, otherwise the address is returned in | |
48 | * standard internet format. | |
49 | * | |
50 | * From: Paul Anderson (23/4/90) | |
51 | */ | |
52 | ||
53 | #include "am.h" | |
54 | ||
55 | #include <sys/ioctl.h> | |
56 | ||
57 | #define NO_SUBNET "notknown" | |
58 | ||
59 | #ifdef SIOCGIFFLAGS | |
60 | #include <net/if.h> | |
61 | #include <netdb.h> | |
62 | ||
63 | #if defined(IFF_LOCAL_LOOPBACK) && !defined(IFF_LOOPBACK) | |
64 | #define IFF_LOOPBACK IFF_LOCAL_LOOPBACK | |
65 | #endif | |
66 | ||
67 | #define GFBUFLEN 1024 | |
68 | #define clist (ifc.ifc_ifcu.ifcu_req) | |
69 | #define count (ifc.ifc_len/sizeof(struct ifreq)) | |
70 | ||
71 | char *getwire P((void)); | |
72 | char *getwire() | |
73 | { | |
74 | struct hostent *hp; | |
75 | struct netent *np; | |
76 | struct ifconf ifc; | |
77 | struct ifreq *ifr; | |
78 | caddr_t cp, cplim; | |
79 | unsigned long address, netmask, subnet; | |
80 | char buf[GFBUFLEN], *s; | |
81 | int sk = -1; | |
82 | ||
83 | /* | |
84 | * Get suitable socket | |
85 | */ | |
86 | if ((sk = socket(AF_INET, SOCK_DGRAM, 0)) < 0) | |
87 | goto out; | |
88 | ||
89 | /* | |
90 | * Fill in ifconf details | |
91 | */ | |
92 | ifc.ifc_len = sizeof buf; | |
93 | ifc.ifc_buf = buf; | |
94 | ||
95 | /* | |
96 | * Get network interface configurations | |
97 | */ | |
98 | if (ioctl(sk, SIOCGIFCONF, (caddr_t) &ifc) < 0) | |
99 | goto out; | |
100 | ||
101 | /* | |
102 | * Upper bound on array | |
103 | */ | |
104 | cplim = buf + ifc.ifc_len; | |
105 | ||
106 | /* | |
107 | * This is some magic to cope with both "traditional" and the | |
108 | * new 4.4BSD-style struct sockaddrs. The new structure has | |
109 | * variable length and a size field to support longer addresses. | |
110 | * AF_LINK is a new definition for 4.4BSD. | |
111 | */ | |
112 | #ifdef AF_LINK | |
113 | #define max(a, b) ((a) > (b) ? (a) : (b)) | |
af359dea | 114 | #define size(ifr) (max((ifr)->ifr_addr.sa_len, sizeof((ifr)->ifr_addr)) + sizeof(ifr->ifr_name)) |
760c99e3 | 115 | #else |
af359dea | 116 | #define size(ifr) sizeof(*ifr) |
760c99e3 JSP |
117 | #endif |
118 | /* | |
119 | * Scan the list looking for a suitable interface | |
120 | */ | |
af359dea | 121 | for (cp = buf; cp < cplim; cp += size(ifr)) { |
760c99e3 JSP |
122 | ifr = (struct ifreq *) cp; |
123 | ||
124 | if (ifr->ifr_addr.sa_family != AF_INET) | |
125 | continue; | |
126 | else | |
127 | address = ((struct sockaddr_in *) &ifr->ifr_addr)->sin_addr.s_addr; | |
128 | ||
129 | /* | |
130 | * Get interface flags | |
131 | */ | |
132 | if (ioctl(sk, SIOCGIFFLAGS, (caddr_t) ifr) < 0) | |
133 | goto out; | |
134 | ||
135 | /* | |
136 | * If the interface is a loopback, or its not running | |
137 | * then ignore it. | |
138 | */ | |
139 | if ((ifr->ifr_flags & IFF_LOOPBACK) != 0) | |
140 | continue; | |
141 | if ((ifr->ifr_flags & IFF_RUNNING) == 0) | |
142 | continue; | |
143 | ||
144 | /* | |
145 | * Get the netmask of this interface | |
146 | */ | |
147 | if (ioctl(sk, SIOCGIFNETMASK, (caddr_t) ifr) < 0) | |
148 | goto out; | |
149 | ||
150 | netmask = ((struct sockaddr_in *) &ifr->ifr_addr)->sin_addr.s_addr; | |
151 | ||
152 | (void) close(sk); | |
153 | ||
154 | /* | |
155 | * Figure out the subnet's network address | |
156 | */ | |
157 | subnet = address & netmask; | |
af359dea C |
158 | #ifdef IN_CLASSA |
159 | if (IN_CLASSA(subnet)) | |
160 | subnet >>= IN_CLASSA_NSHIFT; | |
161 | else if (IN_CLASSB(subnet)) | |
162 | subnet >>= IN_CLASSB_NSHIFT; | |
163 | else if (IN_CLASSC(subnet)) | |
164 | subnet >>= IN_CLASSC_NSHIFT; | |
165 | #endif | |
760c99e3 JSP |
166 | /* |
167 | * Now get a usable name. | |
168 | * First use the network database, | |
169 | * then the host database, | |
170 | * and finally just make a dotted quad. | |
171 | */ | |
172 | np = getnetbyaddr(subnet, AF_INET); | |
173 | if (np) | |
174 | s = np->n_name; | |
175 | else { | |
af359dea | 176 | subnet = address & netmask; |
760c99e3 JSP |
177 | hp = gethostbyaddr((char *) &subnet, 4, AF_INET); |
178 | if (hp) | |
179 | s = hp->h_name; | |
180 | else | |
181 | s = inet_dquad(buf, subnet); | |
182 | } | |
183 | ||
184 | return strdup(s); | |
185 | } | |
186 | ||
187 | out: | |
188 | if (sk >= 0) | |
189 | (void) close(sk); | |
190 | return strdup(NO_SUBNET); | |
191 | } | |
192 | ||
193 | #else | |
194 | ||
195 | char *getwire P((void)); | |
196 | char *getwire() | |
197 | { | |
198 | return strdup(NO_SUBNET); | |
199 | } | |
200 | #endif /* SIOCGIFFLAGS */ |