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*/
1 /*
2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
5 *
6 * Interface (streams) handling functions.
7 *
8 * Version: @(#)dev.c 1.28 20/12/93
9 *
10 * Authors: Ross Biro, <bir7@leland.Stanford.Edu>
11 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 * Mark Evans, <evansmp@uhura.aston.ac.uk>
13 *
14 * Fixes:
15 * Alan Cox: check_addr returns a value for a wrong subnet
16 * ie not us but don't forward this!
17 * Alan Cox: block timer if the inet_bh handler is running
18 * Alan Cox: generic queue code added. A lot neater now
19 * C.E.Hawkins: SIOCGIFCONF only reports 'upped' interfaces
20 * C.E.Hawkins: IFF_PROMISC support
21 * Alan Cox: Supports Donald Beckers new hardware
22 * multicast layer, but not yet multicast lists.
23 * Alan Cox: ip_addr_match problems with class A/B nets.
24 * C.E.Hawkins IP 0.0.0.0 and also same net route fix. [FIXME: Ought to cause ICMP_REDIRECT]
25 * Alan Cox: Removed bogus subnet check now the subnet code
26 * a) actually works for all A/B nets
27 * b) doesn't forward off the same interface.
28 * Alan Cox: Multiple extra protocols
29 * Alan Cox: A Couple more escaped verify_area calls die
30 * Alan Cox: IP_SET_DEV is gone (forever) as per Fred's comment.
31 * Alan Cox: Grand tidy up ready for the big day.
32 * Alan Cox: Handles dev_open errors correctly.
33 * Alan Cox: IP and generic parts split
34 *
35 * This program is free software; you can redistribute it and/or
36 * modify it under the terms of the GNU General Public License
37 * as published by the Free Software Foundation; either version
38 * 2 of the License, or (at your option) any later version.
39 */
40
41 #include <asm/segment.h>
42 #include <asm/system.h>
43 #include <asm/bitops.h>
44 #include <linux/config.h>
45 #include <linux/types.h>
46 #include <linux/kernel.h>
47 #include <linux/sched.h>
48 #include <linux/string.h>
49 #include <linux/mm.h>
50 #include <linux/socket.h>
51 #include <linux/sockios.h>
52 #include <linux/in.h>
53 #include <linux/errno.h>
54 #include <linux/interrupt.h>
55 #include <linux/if_ether.h>
56 #include "inet.h"
57 #include "devinet.h"
58 #include "eth.h"
59 #include "ip.h"
60 #include "route.h"
61 #include "protocol.h"
62 #include "tcp.h"
63 #include "skbuff.h"
64
65
66 /*
67 * Determine a default network mask, based on the IP address.
68 */
69
70 unsigned long ip_get_mask(unsigned long addr)
/* ![[next]](../icons/right.png)
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*/
71 {
72 unsigned long dst;
73
74 if (addr == 0L)
75 return(0L); /* special case */
76
77 dst = ntohl(addr);
78 if (IN_CLASSA(dst))
79 return(htonl(IN_CLASSA_NET));
80 if (IN_CLASSB(dst))
81 return(htonl(IN_CLASSB_NET));
82 if (IN_CLASSC(dst))
83 return(htonl(IN_CLASSC_NET));
84
85 /* Something else, probably a subnet. */
86 return(0);
87 }
88
89 /*
90 * See if a pair of addresses match.
91 */
92
93 int ip_addr_match(unsigned long me, unsigned long him)
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*/
94 {
95 int i;
96 unsigned long mask=0xFFFFFFFF;
97 DPRINTF((DBG_DEV, "ip_addr_match(%s, ", in_ntoa(me)));
98 DPRINTF((DBG_DEV, "%s)\n", in_ntoa(him)));
99
100 /* Fast path for 99.9% of cases */
101 if (me == him)
102 return(1);
103
104 for (i = 0; i < 4; i++, me >>= 8, him >>= 8, mask >>= 8)
105 {
106 if ((me & 0xFF) != (him & 0xFF))
107 {
108 /*
109 * The only way this could be a match is for
110 * the rest of addr1 to be 0 or 255.
111 */
112 if (me != 0 && me != mask)
113 return(0);
114 return(1);
115 }
116 }
117 return(1);
118 }
119
120
121 /*
122 * Check the address for our address, broadcasts, etc.
123 *
124 * This routine is used a lot, and in many time critical
125 * places. It's already _TOO_ slow so be careful how you
126 * alter it.
127 */
128
129 int chk_addr(unsigned long addr)
/* */
130 {
131 struct device *dev;
132 unsigned long dst;
133
134 DPRINTF((DBG_DEV, "chk_addr(%s) --> ", in_ntoa(addr)));
135 dst = ntohl(addr);
136
137 /*
138 * Accept both `all ones' and `all zeros' as BROADCAST.
139 * All 0's is the old BSD broadcast.
140 */
141
142 if (dst == INADDR_ANY || dst == INADDR_BROADCAST)
143 {
144 DPRINTF((DBG_DEV, "BROADCAST\n"));
145 return(IS_BROADCAST);
146 }
147
148 /* Accept all of the `loopback' class A net. */
149 if ((dst & IN_CLASSA_NET) == 0x7F000000L)
150 {
151 DPRINTF((DBG_DEV, "LOOPBACK\n"));
152
153 /*
154 * We force `loopback' to be equal to MY_ADDR.
155 */
156 return(IS_MYADDR);
157 /* return(IS_LOOPBACK); */
158 }
159
160 /* OK, now check the interface addresses. */
161 for (dev = dev_base; dev != NULL; dev = dev->next)
162 {
163 if (!(dev->flags&IFF_UP))
164 continue;
165 if ((dev->pa_addr == 0)/* || (dev->flags&IFF_PROMISC)*/)
166 return(IS_MYADDR);
167 /* Is it the exact IP address? */
168 if (addr == dev->pa_addr)
169 {
170 DPRINTF((DBG_DEV, "MYADDR\n"));
171 return(IS_MYADDR);
172 }
173
174 /* Nope. Check for a subnetwork broadcast. */
175 if ((addr & dev->pa_mask) == (dev->pa_addr & dev->pa_mask))
176 {
177 if ((addr & ~dev->pa_mask) == 0)
178 {
179 DPRINTF((DBG_DEV, "SUBBROADCAST-0\n"));
180 return(IS_BROADCAST);
181 }
182 if (((addr & ~dev->pa_mask) | dev->pa_mask)
183 == INADDR_BROADCAST)
184 {
185 DPRINTF((DBG_DEV, "SUBBROADCAST-1\n"));
186 return(IS_BROADCAST);
187 }
188 }
189
190 /* Nope. Check for Network broadcast. */
191 if(IN_CLASSA(dst))
192 {
193 if( addr == (dev->pa_addr | 0xffffff00))
194 {
195 DPRINTF((DBG_DEV, "CLASS A BROADCAST-1\n"));
196 return(IS_BROADCAST);
197 }
198 }
199 else if(IN_CLASSB(dst))
200 {
201 if( addr == (dev->pa_addr | 0xffff0000))
202 {
203 DPRINTF((DBG_DEV, "CLASS B BROADCAST-1\n"));
204 return(IS_BROADCAST);
205 }
206 }
207 else
208 { /* IN_CLASSC */
209 if( addr == (dev->pa_addr | 0xff000000))
210 {
211 DPRINTF((DBG_DEV, "CLASS C BROADCAST-1\n"));
212 return(IS_BROADCAST);
213 }
214 }
215 }
216
217 DPRINTF((DBG_DEV, "NONE\n"));
218
219 return(0); /* no match at all */
220 }
221
222
223 /*
224 * Retrieve our own address.
225 * Because the loopback address (127.0.0.1) is already recognized
226 * automatically, we can use the loopback interface's address as
227 * our "primary" interface. This is the addressed used by IP et
228 * al when it doesn't know which address to use (i.e. it does not
229 * yet know from or to which interface to go...).
230 */
231
232 unsigned long my_addr(void)
/* */
233 {
234 struct device *dev;
235
236 for (dev = dev_base; dev != NULL; dev = dev->next)
237 {
238 if (dev->flags & IFF_LOOPBACK)
239 return(dev->pa_addr);
240 }
241 return(0);
242 }
243
244
245
246 /*
247 * Find an interface that can handle addresses for a certain address.
248 */
249
250 struct device *dev_check(unsigned long addr)
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*/
251 {
252 struct device *dev;
253
254 for (dev = dev_base; dev; dev = dev->next)
255 if ((dev->flags & IFF_UP) && (dev->flags & IFF_POINTOPOINT) &&
256 (addr == dev->pa_dstaddr))
257 return dev;
258 for (dev = dev_base; dev; dev = dev->next)
259 if ((dev->flags & IFF_UP) && !(dev->flags & IFF_POINTOPOINT) &&
260 (dev->flags & IFF_LOOPBACK ? (addr == dev->pa_addr) :
261 (dev->pa_mask & addr) == (dev->pa_addr & dev->pa_mask)))
262 break;
263 /* no need to check broadcast addresses */
264 return dev;
265 }
266
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*/