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/*

 *      AX.25 release 037

 *

 *      This code REQUIRES 2.1.15 or higher/ NET3.038

 *

 *      This module:

 *              This module is free software; you can redistribute it and/or

 *              modify it under the terms of the GNU General Public License

 *              as published by the Free Software Foundation; either version

 *              2 of the License, or (at your option) any later version.

 *

 *      History

 *      AX.25 036       Jonathan(G4KLX) Split from af_ax25.c.

 */

#include <linux/config.h>

#include <linux/errno.h>

#include <linux/types.h>

#include <linux/socket.h>

#include <linux/in.h>

#include <linux/kernel.h>

#include <linux/sched.h>

#include <linux/timer.h>

#include <linux/string.h>

#include <linux/sockios.h>

#include <linux/net.h>

#include <net/ax25.h>

#include <linux/inet.h>

#include <linux/netdevice.h>

#include <linux/if_arp.h>

#include <linux/skbuff.h>

#include <net/sock.h>

#include <asm/uaccess.h>

#include <asm/system.h>

#include <linux/fcntl.h>

#include <linux/termios.h>      /* For TIOCINQ/OUTQ */

#include <linux/mm.h>

#include <linux/interrupt.h>

#include <linux/notifier.h>

#include <linux/proc_fs.h>

#include <linux/stat.h>

#include <linux/netfilter.h>

#include <linux/sysctl.h>

#include <net/ip.h>

#include <net/arp.h>

/*

 *      IP over AX.25 encapsulation.

 */

/*

 *      Shove an AX.25 UI header on an IP packet and handle ARP

 */

#ifdef CONFIG_INET

int ax25_encapsulate(struct sk_buff *skb, struct net_device *dev, unsigned short type, void *daddr, void *saddr, unsigned len)

{

        unsigned char *buff;

        /* they sometimes come back to us... */

        if (type == ETH_P_AX25)

                return 0;

        /* header is an AX.25 UI frame from us to them */

        buff = skb_push(skb, AX25_HEADER_LEN);

        *buff++ = 0x00; /* KISS DATA */

        if (daddr != NULL)

                memcpy(buff, daddr, dev->addr_len);     /* Address specified */

        buff[6] &= ~AX25_CBIT;

        buff[6] &= ~AX25_EBIT;

        buff[6] |= AX25_SSSID_SPARE;

        buff    += AX25_ADDR_LEN;

        if (saddr != NULL)

                memcpy(buff, saddr, dev->addr_len);

        else

                memcpy(buff, dev->dev_addr, dev->addr_len);

        buff[6] &= ~AX25_CBIT;

        buff[6] |= AX25_EBIT;

        buff[6] |= AX25_SSSID_SPARE;

        buff    += AX25_ADDR_LEN;

        *buff++  = AX25_UI;     /* UI */

        /* Append a suitable AX.25 PID */

        switch (type) {

                case ETH_P_IP:

                        *buff++ = AX25_P_IP;

                        break;

                case ETH_P_ARP:

                        *buff++ = AX25_P_ARP;

                        break;

                default:

                        printk(KERN_ERR "AX.25: ax25_encapsulate - wrong protocol type 0x%2.2x\n", type);

                        *buff++ = 0;

                        break;

        }

        if (daddr != NULL)

                return AX25_HEADER_LEN;

        return -AX25_HEADER_LEN;        /* Unfinished header */

}

int ax25_rebuild_header(struct sk_buff *skb)

{

        struct sk_buff *ourskb;

        unsigned char *bp  = skb->data;

        struct net_device *dev;

        ax25_address *src, *dst;

        ax25_route *route;

        ax25_dev *ax25_dev;

        dst = (ax25_address *)(bp + 1);

        src = (ax25_address *)(bp + 8);

        if (arp_find(bp + 1, skb))

                return 1;

        route    = ax25_rt_find_route(dst, NULL);

        dev      = route->dev;

        if (dev == NULL)

                dev = skb->dev;

        if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)

                return 1;

        if (bp[16] == AX25_P_IP) {

                if (route->ip_mode == 'V' || (route->ip_mode == ' ' && ax25_dev->values[AX25_VALUES_IPDEFMODE])) {

                        /*

                         *      We copy the buffer and release the original thereby

                         *      keeping it straight

                         *

                         *      Note: we report 1 back so the caller will

                         *      not feed the frame direct to the physical device

                         *      We don't want that to happen. (It won't be upset

                         *      as we have pulled the frame from the queue by

                         *      freeing it).

                         *

                         *      NB: TCP modifies buffers that are still

                         *      on a device queue, thus we use skb_copy()

                         *      instead of using skb_clone() unless this

                         *      gets fixed.

                         */

                        ax25_address src_c;

                        ax25_address dst_c;

                        if ((ourskb = skb_copy(skb, GFP_ATOMIC)) == NULL) {

                                kfree_skb(skb);

                                return 1;

                        }

                        if (skb->sk != NULL)

                                skb_set_owner_w(ourskb, skb->sk);

                        kfree_skb(skb);

                        /* dl9sau: bugfix

                         * after kfree_skb(), dst and src which were pointer

                         * to bp which is part of skb->data would not be valid

                         * anymore hope that after skb_pull(ourskb, ..) our

                         * dsc_c and src_c will not become invalid

                         */

                        bp  = ourskb->data;

                        dst_c = *(ax25_address *)(bp + 1);

                        src_c = *(ax25_address *)(bp + 8);

                        skb_pull(ourskb, AX25_HEADER_LEN - 1);  /* Keep PID */

                        ourskb->nh.raw = ourskb->data;

                        ax25_send_frame(ourskb, ax25_dev->values[AX25_VALUES_PACLEN], &src_c,

&dst_c, route->digipeat, dev);

                        return 1;

                }

        }

        bp[7]  &= ~AX25_CBIT;

        bp[7]  &= ~AX25_EBIT;

        bp[7]  |= AX25_SSSID_SPARE;

        bp[14] &= ~AX25_CBIT;

        bp[14] |= AX25_EBIT;

        bp[14] |= AX25_SSSID_SPARE;

        skb_pull(skb, AX25_KISS_HEADER_LEN);

        if (route->digipeat != NULL) {

                if ((ourskb = ax25_rt_build_path(skb, src, dst, route->digipeat)) == NULL) {

                        kfree_skb(skb);

                        return 1;

                }

                skb = ourskb;

        }

        skb->dev      = dev;

        ax25_queue_xmit(skb);

        return 1;

}

#else   /* INET */

int ax25_encapsulate(struct sk_buff *skb, struct net_device *dev, unsigned short type, void *daddr, void *saddr, unsigned len)

{

        return -AX25_HEADER_LEN;

}

int ax25_rebuild_header(struct sk_buff *skb)

{

        return 1;

}

#endif