[deliverable/linux.git] / net / ax25 / ax25_ip.c

/*
 * This program 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.
 *
 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
 */
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/slab.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 <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

static int ax25_hard_header(struct sk_buff *skb, struct net_device *dev,
			    unsigned short type, const void *daddr,
			    const void *saddr, unsigned int 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_hard_header - wrong protocol type 0x%2.2x\n", type);
		*buff++ = 0;
		break;
	}

	if (daddr != NULL)
		return AX25_HEADER_LEN;

	return -AX25_HEADER_LEN;	/* Unfinished header */
}

static int ax25_rebuild_header(struct sk_buff *skb)
{
	struct sk_buff *ourskb;
	unsigned char *bp  = skb->data;
	ax25_route *route;
	struct net_device *dev = NULL;
	ax25_address *src, *dst;
	ax25_digi *digipeat = NULL;
	ax25_dev *ax25_dev;
	ax25_cb *ax25;
	char ip_mode = ' ';

	dst = (ax25_address *)(bp + 1);
	src = (ax25_address *)(bp + 8);

	if (arp_find(bp + 1, skb))
		return 1;

	route = ax25_get_route(dst, NULL);
	if (route) {
		digipeat = route->digipeat;
		dev = route->dev;
		ip_mode = route->ip_mode;
	}

	if (dev == NULL)
		dev = skb->dev;

	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) {
		kfree_skb(skb);
		goto put;
	}

	if (bp[16] == AX25_P_IP) {
		if (ip_mode == 'V' || (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);
				goto put;
			}

			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 */
			skb_reset_network_header(ourskb);

			ax25=ax25_send_frame(
			    ourskb,
			    ax25_dev->values[AX25_VALUES_PACLEN],
			    &src_c,
			    &dst_c, digipeat, dev);
			if (ax25) {
				ax25_cb_put(ax25);
			}
			goto put;
		}
	}

	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 (digipeat != NULL) {
		if ((ourskb = ax25_rt_build_path(skb, src, dst, route->digipeat)) == NULL) {
			kfree_skb(skb);
			goto put;
		}

		skb = ourskb;
	}

	ax25_queue_xmit(skb, dev);

put:
	if (route)
		ax25_put_route(route);

	return 1;
}

#else	/* INET */

static int ax25_hard_header(struct sk_buff *skb, struct net_device *dev,
			    unsigned short type, const void *daddr,
			    const void *saddr, unsigned int len)
{
	return -AX25_HEADER_LEN;
}

static int ax25_rebuild_header(struct sk_buff *skb)
{
	return 1;
}

#endif

const struct header_ops ax25_header_ops = {
	.create = ax25_hard_header,
	.rebuild = ax25_rebuild_header,
};

EXPORT_SYMBOL(ax25_header_ops);
Commit	Line	Data
1da177e4 LT	1	/*
	2	* This program is free software; you can redistribute it and/or modify
	3	* it under the terms of the GNU General Public License as published by
	4	* the Free Software Foundation; either version 2 of the License, or
	5	* (at your option) any later version.
	6	*
	7	* Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
	8	*/
1da177e4 LT	9	#include <linux/errno.h>
	10	#include <linux/types.h>
	11	#include <linux/socket.h>
	12	#include <linux/in.h>
	13	#include <linux/kernel.h>
70868eac	14	#include <linux/module.h>
1da177e4 LT	15	#include <linux/timer.h>
	16	#include <linux/string.h>
	17	#include <linux/sockios.h>
	18	#include <linux/net.h>
5a0e3ad6	19	#include <linux/slab.h>
1da177e4 LT	20	#include <net/ax25.h>
	21	#include <linux/inet.h>
	22	#include <linux/netdevice.h>
	23	#include <linux/if_arp.h>
	24	#include <linux/skbuff.h>
	25	#include <net/sock.h>
	26	#include <asm/uaccess.h>
1da177e4 LT	27	#include <linux/fcntl.h>
	28	#include <linux/termios.h> /* For TIOCINQ/OUTQ */
	29	#include <linux/mm.h>
	30	#include <linux/interrupt.h>
	31	#include <linux/notifier.h>
	32	#include <linux/proc_fs.h>
	33	#include <linux/stat.h>
	34	#include <linux/netfilter.h>
	35	#include <linux/sysctl.h>
	36	#include <net/ip.h>
	37	#include <net/arp.h>
	38
	39	/*
	40	* IP over AX.25 encapsulation.
	41	*/
	42
	43	/*
	44	* Shove an AX.25 UI header on an IP packet and handle ARP
	45	*/
	46
	47	#ifdef CONFIG_INET
	48
46d4e47a EB	49	static int ax25_hard_header(struct sk_buff skb, struct net_device dev,
	50	unsigned short type, const void *daddr,
	51	const void *saddr, unsigned int len)
1da177e4 LT	52	{
	53	unsigned char *buff;
	54
	55	/* they sometimes come back to us... */
	56	if (type == ETH_P_AX25)
	57	return 0;
	58
528930b9 YH	59	/* header is an AX.25 UI frame from us to them */
	60	buff = skb_push(skb, AX25_HEADER_LEN);
	61	buff++ = 0x00; / KISS DATA */
1da177e4 LT	62
	63	if (daddr != NULL)
	64	memcpy(buff, daddr, dev->addr_len); /* Address specified */
	65
528930b9 YH	66	buff[6] &= ~AX25_CBIT;
	67	buff[6] &= ~AX25_EBIT;
	68	buff[6] \|= AX25_SSSID_SPARE;
	69	buff += AX25_ADDR_LEN;
	70
	71	if (saddr != NULL)
	72	memcpy(buff, saddr, dev->addr_len);
	73	else
	74	memcpy(buff, dev->dev_addr, dev->addr_len);
	75
	76	buff[6] &= ~AX25_CBIT;
	77	buff[6] \|= AX25_EBIT;
	78	buff[6] \|= AX25_SSSID_SPARE;
	79	buff += AX25_ADDR_LEN;
	80
	81	buff++ = AX25_UI; / UI */
	82
	83	/* Append a suitable AX.25 PID */
	84	switch (type) {
	85	case ETH_P_IP:
	86	*buff++ = AX25_P_IP;
	87	break;
	88	case ETH_P_ARP:
	89	*buff++ = AX25_P_ARP;
	90	break;
	91	default:
	92	printk(KERN_ERR "AX.25: ax25_hard_header - wrong protocol type 0x%2.2x\n", type);
	93	*buff++ = 0;
	94	break;
	95	}
1da177e4 LT	96
1da177e4 LT	97	if (daddr != NULL)
528930b9	98	return AX25_HEADER_LEN;
1da177e4 LT	99
	100	return -AX25_HEADER_LEN; /* Unfinished header */
	101	}
	102
46d4e47a	103	static int ax25_rebuild_header(struct sk_buff *skb)
1da177e4 LT	104	{
	105	struct sk_buff *ourskb;
	106	unsigned char *bp = skb->data;
006f68b8 RBD	107	ax25_route *route;
006f68b8 RBD	108	struct net_device *dev = NULL;
1da177e4	109	ax25_address src, dst;
006f68b8	110	ax25_digi *digipeat = NULL;
1da177e4	111	ax25_dev *ax25_dev;
1da177e4	112	ax25_cb *ax25;
006f68b8	113	char ip_mode = ' ';
1da177e4 LT	114
	115	dst = (ax25_address *)(bp + 1);
	116	src = (ax25_address *)(bp + 8);
	117
528930b9 YH	118	if (arp_find(bp + 1, skb))
528930b9 YH	119	return 1;
1da177e4	120
006f68b8 RBD	121	route = ax25_get_route(dst, NULL);
	122	if (route) {
	123	digipeat = route->digipeat;
	124	dev = route->dev;
	125	ip_mode = route->ip_mode;
3ff50b79	126	}
1da177e4 LT	127
	128	if (dev == NULL)
	129	dev = skb->dev;
	130
528930b9	131	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) {
e18dbd05	132	kfree_skb(skb);
528930b9	133	goto put;
1da177e4 LT	134	}
	135
	136	if (bp[16] == AX25_P_IP) {
006f68b8	137	if (ip_mode == 'V' \|\| (ip_mode == ' ' && ax25_dev->values[AX25_VALUES_IPDEFMODE])) {
1da177e4 LT	138	/*
	139	* We copy the buffer and release the original thereby
	140	* keeping it straight
	141	*
	142	* Note: we report 1 back so the caller will
	143	* not feed the frame direct to the physical device
	144	* We don't want that to happen. (It won't be upset
	145	* as we have pulled the frame from the queue by
	146	* freeing it).
	147	*
	148	* NB: TCP modifies buffers that are still
	149	* on a device queue, thus we use skb_copy()
	150	* instead of using skb_clone() unless this
	151	* gets fixed.
	152	*/
	153
	154	ax25_address src_c;
	155	ax25_address dst_c;
	156
	157	if ((ourskb = skb_copy(skb, GFP_ATOMIC)) == NULL) {
	158	kfree_skb(skb);
	159	goto put;
	160	}
	161
	162	if (skb->sk != NULL)
	163	skb_set_owner_w(ourskb, skb->sk);
	164
	165	kfree_skb(skb);
	166	/* dl9sau: bugfix
	167	* after kfree_skb(), dst and src which were pointer
	168	* to bp which is part of skb->data would not be valid
	169	* anymore hope that after skb_pull(ourskb, ..) our
	170	* dsc_c and src_c will not become invalid
	171	*/
	172	bp = ourskb->data;
	173	dst_c = (ax25_address )(bp + 1);
	174	src_c = (ax25_address )(bp + 8);
	175
	176	skb_pull(ourskb, AX25_HEADER_LEN - 1); /* Keep PID */
c1d2bbe1	177	skb_reset_network_header(ourskb);
1da177e4 LT	178
1da177e4 LT	179	ax25=ax25_send_frame(
528930b9 YH	180	ourskb,
528930b9 YH	181	ax25_dev->values[AX25_VALUES_PACLEN],
1da177e4	182	&src_c,
006f68b8	183	&dst_c, digipeat, dev);
1da177e4 LT	184	if (ax25) {
	185	ax25_cb_put(ax25);
	186	}
	187	goto put;
	188	}
	189	}
	190
528930b9 YH	191	bp[7] &= ~AX25_CBIT;
	192	bp[7] &= ~AX25_EBIT;
	193	bp[7] \|= AX25_SSSID_SPARE;
1da177e4	194
528930b9 YH	195	bp[14] &= ~AX25_CBIT;
	196	bp[14] \|= AX25_EBIT;
	197	bp[14] \|= AX25_SSSID_SPARE;
1da177e4 LT	198
	199	skb_pull(skb, AX25_KISS_HEADER_LEN);
	200
006f68b8	201	if (digipeat != NULL) {
1da177e4 LT	202	if ((ourskb = ax25_rt_build_path(skb, src, dst, route->digipeat)) == NULL) {
	203	kfree_skb(skb);
	204	goto put;
	205	}
	206
	207	skb = ourskb;
	208	}
	209
29c4be51	210	ax25_queue_xmit(skb, dev);
1da177e4 LT	211
1da177e4 LT	212	put:
006f68b8 RBD	213	if (route)
006f68b8 RBD	214	ax25_put_route(route);
1da177e4	215
528930b9	216	return 1;
1da177e4 LT	217	}
	218
	219	#else /* INET */
	220
46d4e47a EB	221	static int ax25_hard_header(struct sk_buff skb, struct net_device dev,
	222	unsigned short type, const void *daddr,
	223	const void *saddr, unsigned int len)
1da177e4 LT	224	{
	225	return -AX25_HEADER_LEN;
	226	}
	227
46d4e47a	228	static int ax25_rebuild_header(struct sk_buff *skb)
1da177e4 LT	229	{
	230	return 1;
	231	}
	232
	233	#endif
	234
3b04ddde SH	235	const struct header_ops ax25_header_ops = {
	236	.create = ax25_hard_header,
	237	.rebuild = ax25_rebuild_header,
	238	};
	239
3b04ddde SH	240	EXPORT_SYMBOL(ax25_header_ops);
3b04ddde SH	241