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[/] [or1k_old/] [trunk/] [uclinux/] [uClinux-2.0.x/] [net/] [ipv4/] [devinet.c] - Blame information for rev 1782

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Line No. Rev Author Line
1 199 simons 
/*
2 
 *      NET3    IP device support routines.
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 *
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 *              This program is free software; you can redistribute it and/or
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 *              modify it under the terms of the GNU General Public License
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 *              as published by the Free Software Foundation; either version
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 *              2 of the License, or (at your option) any later version.
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 *
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 *      Derived from the IP parts of dev.c 1.0.19
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 *              Authors:        Ross Biro, <bir7@leland.Stanford.Edu>
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 *                              Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
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 *                              Mark Evans, <evansmp@uhura.aston.ac.uk>
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 *
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 *      Additional Authors:
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 *              Alan Cox, <gw4pts@gw4pts.ampr.org>
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 */
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#include <linux/config.h>       /* For CONFIG_IP_CLASSLESS */
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#include <asm/segment.h>
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#include <asm/system.h>
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#include <asm/bitops.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/string.h>
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#include <linux/mm.h>
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#include <linux/socket.h>
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#include <linux/sockios.h>
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#include <linux/in.h>
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#include <linux/errno.h>
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#include <linux/interrupt.h>
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#include <linux/if_ether.h>
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#include <linux/inet.h>
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#include <linux/netdevice.h>
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#include <linux/etherdevice.h>
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#include <net/ip.h>
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#include <net/route.h>
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#include <net/protocol.h>
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#include <net/tcp.h>
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#include <linux/skbuff.h>
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#include <net/sock.h>
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#include <net/arp.h>
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/*
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 *      Determine a default network mask, based on the IP address.
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 */
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unsigned long ip_get_mask(unsigned long addr)
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{
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        unsigned long dst;
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        if (addr == 0L)
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                return(0L);     /* special case */
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        dst = ntohl(addr);
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        if (IN_CLASSA(dst))
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                return(htonl(IN_CLASSA_NET));
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        if (IN_CLASSB(dst))
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                return(htonl(IN_CLASSB_NET));
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        if (IN_CLASSC(dst))
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                return(htonl(IN_CLASSC_NET));
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        /*
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         *      Something else, probably a multicast.
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         */
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        return(0);
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}
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/*
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 *      Check the address for our address, broadcasts, etc.
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 *
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 *      I intend to fix this to at the very least cache the last
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 *      resolved entry.
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 */
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int ip_chk_addr(unsigned long addr)
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{
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        struct device *dev;
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#ifndef CONFIG_IP_CLASSLESS
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        unsigned long mask;
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#endif
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        /*
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         *      Accept both `all ones' and `all zeros' as BROADCAST.
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         *      (Support old BSD in other words). This old BSD
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         *      support will go very soon as it messes other things
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         *      up.
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         *      Also accept `loopback broadcast' as BROADCAST.
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         */
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        if (addr == INADDR_ANY || addr == INADDR_BROADCAST ||
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            addr == htonl(0x7FFFFFFFL))
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                return IS_BROADCAST;
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#ifndef  CONFIG_IP_CLASSLESS
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        mask = ip_get_mask(addr);
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        /*
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         *      Accept all of the `loopback' class A net.
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         */
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        if ((addr & mask) == htonl(0x7F000000L))
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                return IS_MYADDR;
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#else
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        if ((addr & htonl(0x7F000000L)) == htonl(0x7F000000L))
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                return IS_MYADDR;
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#endif
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        /*
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         *      OK, now check the interface addresses. We could
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         *      speed this by keeping a dev and a dev_up chain.
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         */
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        for (dev = dev_base; dev != NULL; dev = dev->next)
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        {
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                if ((!(dev->flags & IFF_UP)) || dev->family!=AF_INET)
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                        continue;
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                /*
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                 *      If the protocol address of the device is 0 this is special
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                 *      and means we are address hunting (eg bootp).
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                 */
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                if (dev->pa_addr == 0)
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                        return IS_MYADDR;
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                /*
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                 *      Is it the exact IP address?
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                 */
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                if (addr == dev->pa_addr)
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                        return IS_MYADDR;
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                /*
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                 *      Is it our broadcast address?
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                 */
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                if ((dev->flags & IFF_BROADCAST) && addr == dev->pa_brdaddr)
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                        return IS_BROADCAST;
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                /*
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                 *      Nope. Check for a subnetwork broadcast.
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                 */
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                if (((addr ^ dev->pa_addr) & dev->pa_mask) == 0)
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                {
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                        if ((addr & ~dev->pa_mask) == 0)
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                                return IS_BROADCAST;
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                        if ((addr & ~dev->pa_mask) == ~dev->pa_mask)
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                                return IS_BROADCAST;
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                }
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#ifndef CONFIG_IP_CLASSLESS
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                /*
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                 *      Nope. Check for Network broadcast.
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                 */
155 
 
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                if (((addr ^ dev->pa_addr) & mask) == 0)
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                {
158 
                        if ((addr & ~mask) == 0)
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                                return IS_BROADCAST;
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                        if ((addr & ~mask) == ~mask)
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                                return IS_BROADCAST;
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                }
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#endif
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        }
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        if(IN_MULTICAST(ntohl(addr)))
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                return IS_MULTICAST;
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        return 0;                /* no match at all */
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}
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170 
 
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/*
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 *      Retrieve our own address.
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 *
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 *      Because the loopback address (127.0.0.1) is already recognized
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 *      automatically, we can use the loopback interface's address as
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 *      our "primary" interface.  This is the address used by IP et
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 *      al when it doesn't know which address to use (i.e. it does not
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 *      yet know from or to which interface to go...).
179 
 */
180 
 
181 
unsigned long ip_my_addr(void)
182 
{
183 
        struct device *dev;
184 
 
185 
        for (dev = dev_base; dev != NULL; dev = dev->next)
186 
        {
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                if (dev->flags & IFF_LOOPBACK)
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                        return(dev->pa_addr);
189 
        }
190 
        return(0);
191 
}
192 
 
193 
/*
194 
 *      Find an interface that can handle addresses for a certain address.
195 
 */
196 
 
197 
struct device * ip_dev_bynet(unsigned long addr, unsigned long mask)
198 
{
199 
        struct device *dev;
200 
        struct device *best_dev = NULL;
201 
        __u32  best_mask = mask;
202 
 
203 
        for (dev = dev_base; dev; dev = dev->next)
204 
        {
205 
                if (!(dev->flags & IFF_UP))
206 
                        continue;
207 
                if (dev->flags & IFF_POINTOPOINT)
208 
                {
209 
                        if (addr == dev->pa_dstaddr)
210 
                                return dev;
211 
                        continue;
212 
                }
213 
                if (dev->pa_mask & (addr ^ dev->pa_addr))
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                        continue;
215 
                if (mask == dev->pa_mask)
216 
                        return dev;
217 
                if (best_dev && (best_mask & dev->pa_mask) != best_mask)
218 
                        continue;
219 
                best_dev = dev;
220 
                best_mask = dev->pa_mask;
221 
        }
222 
        return best_dev;
223 
}
224 
 
225 
/*
226 
 *      Find the first device with a given source address.
227 
 */
228 
 
229 
struct device *ip_dev_find(unsigned long addr)
230 
{
231 
        struct device *dev;
232 
        for(dev = dev_base; dev; dev=dev->next)
233 
        {
234 
                if((dev->flags&IFF_UP) && dev->pa_addr==addr)
235 
                        return dev;
236 
        }
237 
        return NULL;
238 
}
239 
 
240 
struct device *dev_getbytype(unsigned short type)
241 
{
242 
        struct device *dev;
243 
 
244 
        for (dev = dev_base; dev != NULL; dev = dev->next)
245 
        {
246 
                if (dev->type == type && !(dev->flags&(IFF_LOOPBACK|IFF_NOARP)))
247 
                        return(dev);
248 
        }
249 
        return(NULL);
250 
}
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