1328a4970Spendry /*
2328a4970Spendry * Copyright (c) 1990 Jan-Simon Pendry
3328a4970Spendry * Copyright (c) 1990 Imperial College of Science, Technology & Medicine
4*4092c5ccSbostic * Copyright (c) 1990, 1993
5*4092c5ccSbostic * The Regents of the University of California. All rights reserved.
6328a4970Spendry *
7328a4970Spendry * This code is derived from software contributed to Berkeley by
8328a4970Spendry * Jan-Simon Pendry at Imperial College, London.
9328a4970Spendry *
108a89c22cSpendry * %sccs.include.redist.c%
11328a4970Spendry *
12*4092c5ccSbostic * @(#)wire.c 8.1 (Berkeley) 06/06/93
13c626267eSpendry *
14cc0207dcSpendry * $Id: wire.c,v 5.2.2.1 1992/02/09 15:09:15 jsp beta $
15c626267eSpendry *
16328a4970Spendry */
17328a4970Spendry
18328a4970Spendry /*
19cc0207dcSpendry * This function returns the subnet (address&netmask) for the primary network
20328a4970Spendry * interface. If the resulting address has an entry in the hosts file, the
21328a4970Spendry * corresponding name is retuned, otherwise the address is returned in
22328a4970Spendry * standard internet format.
23cc0207dcSpendry * As a side-effect, a list of local IP/net address is recorded for use
24cc0207dcSpendry * by the islocalnet() function.
25328a4970Spendry *
26cc0207dcSpendry * Derived from original by Paul Anderson (23/4/90)
27cc0207dcSpendry * Updates from Dirk Grunwald (11/11/91)
28328a4970Spendry */
29328a4970Spendry
30328a4970Spendry #include "am.h"
31328a4970Spendry
32328a4970Spendry #include <sys/ioctl.h>
33328a4970Spendry
34328a4970Spendry #define NO_SUBNET "notknown"
35328a4970Spendry
36cc0207dcSpendry /*
37cc0207dcSpendry * List of locally connected networks
38cc0207dcSpendry */
39cc0207dcSpendry typedef struct addrlist addrlist;
40cc0207dcSpendry struct addrlist {
41cc0207dcSpendry addrlist *ip_next;
42cc0207dcSpendry unsigned long ip_addr;
43cc0207dcSpendry unsigned long ip_mask;
44cc0207dcSpendry };
45cc0207dcSpendry static addrlist *localnets = 0;
46cc0207dcSpendry
47328a4970Spendry #ifdef SIOCGIFFLAGS
48cc0207dcSpendry #ifdef STELLIX
49cc0207dcSpendry #include <sys/sema.h>
50cc0207dcSpendry #endif /* STELLIX */
51328a4970Spendry #include <net/if.h>
52328a4970Spendry #include <netdb.h>
53328a4970Spendry
54328a4970Spendry #if defined(IFF_LOCAL_LOOPBACK) && !defined(IFF_LOOPBACK)
55328a4970Spendry #define IFF_LOOPBACK IFF_LOCAL_LOOPBACK
56328a4970Spendry #endif
57328a4970Spendry
58328a4970Spendry #define GFBUFLEN 1024
59328a4970Spendry #define clist (ifc.ifc_ifcu.ifcu_req)
60328a4970Spendry #define count (ifc.ifc_len/sizeof(struct ifreq))
61328a4970Spendry
62328a4970Spendry char *getwire P((void));
getwire()63328a4970Spendry char *getwire()
64328a4970Spendry {
65328a4970Spendry struct hostent *hp;
66328a4970Spendry struct netent *np;
67328a4970Spendry struct ifconf ifc;
68328a4970Spendry struct ifreq *ifr;
69328a4970Spendry caddr_t cp, cplim;
70328a4970Spendry unsigned long address, netmask, subnet;
71328a4970Spendry char buf[GFBUFLEN], *s;
72328a4970Spendry int sk = -1;
73cc0207dcSpendry char *netname = 0;
74328a4970Spendry
75328a4970Spendry /*
76328a4970Spendry * Get suitable socket
77328a4970Spendry */
78328a4970Spendry if ((sk = socket(AF_INET, SOCK_DGRAM, 0)) < 0)
79328a4970Spendry goto out;
80328a4970Spendry
81328a4970Spendry /*
82328a4970Spendry * Fill in ifconf details
83328a4970Spendry */
84328a4970Spendry ifc.ifc_len = sizeof buf;
85328a4970Spendry ifc.ifc_buf = buf;
86328a4970Spendry
87328a4970Spendry /*
88328a4970Spendry * Get network interface configurations
89328a4970Spendry */
90328a4970Spendry if (ioctl(sk, SIOCGIFCONF, (caddr_t) &ifc) < 0)
91328a4970Spendry goto out;
92328a4970Spendry
93328a4970Spendry /*
94328a4970Spendry * Upper bound on array
95328a4970Spendry */
96328a4970Spendry cplim = buf + ifc.ifc_len;
97328a4970Spendry
98328a4970Spendry /*
99328a4970Spendry * This is some magic to cope with both "traditional" and the
100328a4970Spendry * new 4.4BSD-style struct sockaddrs. The new structure has
101328a4970Spendry * variable length and a size field to support longer addresses.
102328a4970Spendry * AF_LINK is a new definition for 4.4BSD.
103328a4970Spendry */
104328a4970Spendry #ifdef AF_LINK
105328a4970Spendry #define max(a, b) ((a) > (b) ? (a) : (b))
106c626267eSpendry #define size(ifr) (max((ifr)->ifr_addr.sa_len, sizeof((ifr)->ifr_addr)) + sizeof(ifr->ifr_name))
107328a4970Spendry #else
108c626267eSpendry #define size(ifr) sizeof(*ifr)
109328a4970Spendry #endif
110328a4970Spendry /*
111328a4970Spendry * Scan the list looking for a suitable interface
112328a4970Spendry */
113c626267eSpendry for (cp = buf; cp < cplim; cp += size(ifr)) {
114cc0207dcSpendry addrlist *al;
115328a4970Spendry ifr = (struct ifreq *) cp;
116328a4970Spendry
117328a4970Spendry if (ifr->ifr_addr.sa_family != AF_INET)
118328a4970Spendry continue;
119328a4970Spendry else
120328a4970Spendry address = ((struct sockaddr_in *) &ifr->ifr_addr)->sin_addr.s_addr;
121328a4970Spendry
122328a4970Spendry /*
123328a4970Spendry * Get interface flags
124328a4970Spendry */
125328a4970Spendry if (ioctl(sk, SIOCGIFFLAGS, (caddr_t) ifr) < 0)
126cc0207dcSpendry continue;
127328a4970Spendry
128328a4970Spendry /*
129328a4970Spendry * If the interface is a loopback, or its not running
130328a4970Spendry * then ignore it.
131328a4970Spendry */
132328a4970Spendry if ((ifr->ifr_flags & IFF_LOOPBACK) != 0)
133328a4970Spendry continue;
134328a4970Spendry if ((ifr->ifr_flags & IFF_RUNNING) == 0)
135328a4970Spendry continue;
136328a4970Spendry
137328a4970Spendry /*
138328a4970Spendry * Get the netmask of this interface
139328a4970Spendry */
140328a4970Spendry if (ioctl(sk, SIOCGIFNETMASK, (caddr_t) ifr) < 0)
141cc0207dcSpendry continue;
142328a4970Spendry
143328a4970Spendry netmask = ((struct sockaddr_in *) &ifr->ifr_addr)->sin_addr.s_addr;
144328a4970Spendry
145cc0207dcSpendry /*
146cc0207dcSpendry * Add interface to local network list
147cc0207dcSpendry */
148cc0207dcSpendry al = ALLOC(addrlist);
149cc0207dcSpendry al->ip_addr = address;
150cc0207dcSpendry al->ip_mask = netmask;
151cc0207dcSpendry al->ip_next = localnets;
152cc0207dcSpendry localnets = al;
153328a4970Spendry
154cc0207dcSpendry if (netname == 0) {
155cc0207dcSpendry unsigned long net;
156cc0207dcSpendry unsigned long mask;
157cc0207dcSpendry unsigned long subnetshift;
158328a4970Spendry /*
159328a4970Spendry * Figure out the subnet's network address
160328a4970Spendry */
161328a4970Spendry subnet = address & netmask;
162cc0207dcSpendry
163c626267eSpendry #ifdef IN_CLASSA
164cc0207dcSpendry subnet = ntohl(subnet);
165cc0207dcSpendry
166cc0207dcSpendry if (IN_CLASSA(subnet)) {
167cc0207dcSpendry mask = IN_CLASSA_NET;
168cc0207dcSpendry subnetshift = 8;
169cc0207dcSpendry } else if (IN_CLASSB(subnet)) {
170cc0207dcSpendry mask = IN_CLASSB_NET;
171cc0207dcSpendry subnetshift = 8;
172cc0207dcSpendry } else {
173cc0207dcSpendry mask = IN_CLASSC_NET;
174cc0207dcSpendry subnetshift = 4;
175cc0207dcSpendry }
176cc0207dcSpendry
177cc0207dcSpendry /*
178cc0207dcSpendry * If there are more bits than the standard mask
179cc0207dcSpendry * would suggest, subnets must be in use.
180cc0207dcSpendry * Guess at the subnet mask, assuming reasonable
181cc0207dcSpendry * width subnet fields.
182193d5679Spendry * XXX: Or-in at least 1 byte's worth of 1s to make
183193d5679Spendry * sure the top bits remain set.
184cc0207dcSpendry */
185cc0207dcSpendry while (subnet &~ mask)
186193d5679Spendry mask = (mask >> subnetshift) | 0xff000000;
187cc0207dcSpendry
188cc0207dcSpendry net = subnet & mask;
189cc0207dcSpendry while ((mask & 1) == 0)
190cc0207dcSpendry mask >>= 1, net >>= 1;
191cc0207dcSpendry
192328a4970Spendry /*
193328a4970Spendry * Now get a usable name.
194328a4970Spendry * First use the network database,
195328a4970Spendry * then the host database,
196328a4970Spendry * and finally just make a dotted quad.
197328a4970Spendry */
198cc0207dcSpendry
199cc0207dcSpendry np = getnetbyaddr(net, AF_INET);
200cc0207dcSpendry #else
201cc0207dcSpendry /* This is probably very wrong. */
202328a4970Spendry np = getnetbyaddr(subnet, AF_INET);
203cc0207dcSpendry #endif /* IN_CLASSA */
204328a4970Spendry if (np)
205328a4970Spendry s = np->n_name;
206328a4970Spendry else {
207c626267eSpendry subnet = address & netmask;
208328a4970Spendry hp = gethostbyaddr((char *) &subnet, 4, AF_INET);
209328a4970Spendry if (hp)
210328a4970Spendry s = hp->h_name;
211328a4970Spendry else
212328a4970Spendry s = inet_dquad(buf, subnet);
213328a4970Spendry }
214cc0207dcSpendry netname = strdup(s);
215cc0207dcSpendry }
216328a4970Spendry }
217328a4970Spendry
218328a4970Spendry out:
219328a4970Spendry if (sk >= 0)
220328a4970Spendry (void) close(sk);
221cc0207dcSpendry if (netname)
222cc0207dcSpendry return netname;
223328a4970Spendry return strdup(NO_SUBNET);
224328a4970Spendry }
225328a4970Spendry
226328a4970Spendry #else
227328a4970Spendry
228328a4970Spendry char *getwire P((void));
getwire()229328a4970Spendry char *getwire()
230328a4970Spendry {
231328a4970Spendry return strdup(NO_SUBNET);
232328a4970Spendry }
233328a4970Spendry #endif /* SIOCGIFFLAGS */
234cc0207dcSpendry
235cc0207dcSpendry /*
236cc0207dcSpendry * Determine whether a network is on a local network
237cc0207dcSpendry * (addr) is in network byte order.
238cc0207dcSpendry */
239cc0207dcSpendry int islocalnet P((unsigned long addr));
islocalnet(addr)240cc0207dcSpendry int islocalnet(addr)
241cc0207dcSpendry unsigned long addr;
242cc0207dcSpendry {
243cc0207dcSpendry addrlist *al;
244cc0207dcSpendry
245cc0207dcSpendry for (al = localnets; al; al = al->ip_next)
246cc0207dcSpendry if (((addr ^ al->ip_addr) & al->ip_mask) == 0)
247cc0207dcSpendry return TRUE;
248cc0207dcSpendry
249cc0207dcSpendry #ifdef DEBUG
250cc0207dcSpendry { char buf[16];
251cc0207dcSpendry plog(XLOG_INFO, "%s is on a remote network", inet_dquad(buf, addr));
252cc0207dcSpendry }
253cc0207dcSpendry #endif
254cc0207dcSpendry return FALSE;
255cc0207dcSpendry }
256