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

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *
 * Copyright (C) Jonathan Naylor G4KLX ([email protected])
 */
#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 <linux/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/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 */
}

netdev_tx_t ax25_ip_xmit(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);

	ax25_route_lock_use();
	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)
			goto put;

		skb = ourskb;
	}

	ax25_queue_xmit(skb, dev);

put:

	ax25_route_lock_unuse();
	return NETDEV_TX_OK;
}

#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;
}

netdev_tx_t ax25_ip_xmit(struct sk_buff *skb)
{
	kfree_skb(skb);
	return NETDEV_TX_OK;
}
#endif

static bool ax25_validate_header(const char *header, unsigned int len)
{
	ax25_digi digi;

	if (!len)
		return false;

	if (header[0])
		return true;

	return ax25_addr_parse(header + 1, len - 1, NULL, NULL, &digi, NULL,
			       NULL);
}

const struct header_ops ax25_header_ops = {
	.create = ax25_hard_header,
	.validate = ax25_validate_header,
};

EXPORT_SYMBOL(ax25_header_ops);
EXPORT_SYMBOL(ax25_ip_xmit);
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
1da177e4	2	/*
1da177e4 LT	3	*
	4	* Copyright (C) Jonathan Naylor G4KLX ([email protected])
	5	*/
1da177e4 LT	6	#include <linux/errno.h>
	7	#include <linux/types.h>
	8	#include <linux/socket.h>
	9	#include <linux/in.h>
	10	#include <linux/kernel.h>
70868eac	11	#include <linux/module.h>
1da177e4 LT	12	#include <linux/timer.h>
	13	#include <linux/string.h>
	14	#include <linux/sockios.h>
	15	#include <linux/net.h>
5a0e3ad6	16	#include <linux/slab.h>
1da177e4 LT	17	#include <net/ax25.h>
	18	#include <linux/inet.h>
	19	#include <linux/netdevice.h>
	20	#include <linux/if_arp.h>
	21	#include <linux/skbuff.h>
	22	#include <net/sock.h>
7c0f6ba6	23	#include <linux/uaccess.h>
1da177e4 LT	24	#include <linux/fcntl.h>
	25	#include <linux/termios.h> /* For TIOCINQ/OUTQ */
	26	#include <linux/mm.h>
	27	#include <linux/interrupt.h>
	28	#include <linux/notifier.h>
	29	#include <linux/proc_fs.h>
	30	#include <linux/stat.h>
1da177e4 LT	31	#include <linux/sysctl.h>
	32	#include <net/ip.h>
	33	#include <net/arp.h>
	34
	35	/*
	36	* IP over AX.25 encapsulation.
	37	*/
	38
	39	/*
	40	* Shove an AX.25 UI header on an IP packet and handle ARP
	41	*/
	42
	43	#ifdef CONFIG_INET
	44
46d4e47a EB	45	static int ax25_hard_header(struct sk_buff skb, struct net_device dev,
	46	unsigned short type, const void *daddr,
	47	const void *saddr, unsigned int len)
1da177e4 LT	48	{
	49	unsigned char *buff;
	50
	51	/* they sometimes come back to us... */
	52	if (type == ETH_P_AX25)
	53	return 0;
	54
528930b9 YH	55	/* header is an AX.25 UI frame from us to them */
	56	buff = skb_push(skb, AX25_HEADER_LEN);
	57	buff++ = 0x00; / KISS DATA */
1da177e4 LT	58
	59	if (daddr != NULL)
	60	memcpy(buff, daddr, dev->addr_len); /* Address specified */
	61
528930b9 YH	62	buff[6] &= ~AX25_CBIT;
	63	buff[6] &= ~AX25_EBIT;
	64	buff[6] \|= AX25_SSSID_SPARE;
	65	buff += AX25_ADDR_LEN;
	66
	67	if (saddr != NULL)
	68	memcpy(buff, saddr, dev->addr_len);
	69	else
	70	memcpy(buff, dev->dev_addr, dev->addr_len);
	71
	72	buff[6] &= ~AX25_CBIT;
	73	buff[6] \|= AX25_EBIT;
	74	buff[6] \|= AX25_SSSID_SPARE;
	75	buff += AX25_ADDR_LEN;
	76
	77	buff++ = AX25_UI; / UI */
	78
	79	/* Append a suitable AX.25 PID */
	80	switch (type) {
	81	case ETH_P_IP:
	82	*buff++ = AX25_P_IP;
	83	break;
	84	case ETH_P_ARP:
	85	*buff++ = AX25_P_ARP;
	86	break;
	87	default:
	88	printk(KERN_ERR "AX.25: ax25_hard_header - wrong protocol type 0x%2.2x\n", type);
	89	*buff++ = 0;
	90	break;
	91	}
1da177e4 LT	92
1da177e4 LT	93	if (daddr != NULL)
528930b9	94	return AX25_HEADER_LEN;
1da177e4 LT	95
	96	return -AX25_HEADER_LEN; /* Unfinished header */
	97	}
	98
1d5da757	99	netdev_tx_t ax25_ip_xmit(struct sk_buff *skb)
1da177e4 LT	100	{
	101	struct sk_buff *ourskb;
	102	unsigned char *bp = skb->data;
006f68b8 RB	103	ax25_route *route;
006f68b8 RB	104	struct net_device *dev = NULL;
1da177e4	105	ax25_address src, dst;
006f68b8	106	ax25_digi *digipeat = NULL;
1da177e4	107	ax25_dev *ax25_dev;
1da177e4	108	ax25_cb *ax25;
006f68b8	109	char ip_mode = ' ';
1da177e4 LT	110
	111	dst = (ax25_address *)(bp + 1);
	112	src = (ax25_address *)(bp + 8);
	113
63530aba	114	ax25_route_lock_use();
006f68b8 RB	115	route = ax25_get_route(dst, NULL);
	116	if (route) {
	117	digipeat = route->digipeat;
	118	dev = route->dev;
	119	ip_mode = route->ip_mode;
3ff50b79	120	}
1da177e4 LT	121
	122	if (dev == NULL)
	123	dev = skb->dev;
	124
528930b9	125	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) {
e18dbd05	126	kfree_skb(skb);
528930b9	127	goto put;
1da177e4 LT	128	}
	129
	130	if (bp[16] == AX25_P_IP) {
006f68b8	131	if (ip_mode == 'V' \|\| (ip_mode == ' ' && ax25_dev->values[AX25_VALUES_IPDEFMODE])) {
1da177e4 LT	132	/*
	133	* We copy the buffer and release the original thereby
	134	* keeping it straight
	135	*
	136	* Note: we report 1 back so the caller will
	137	* not feed the frame direct to the physical device
	138	* We don't want that to happen. (It won't be upset
	139	* as we have pulled the frame from the queue by
	140	* freeing it).
	141	*
	142	* NB: TCP modifies buffers that are still
	143	* on a device queue, thus we use skb_copy()
	144	* instead of using skb_clone() unless this
	145	* gets fixed.
	146	*/
	147
	148	ax25_address src_c;
	149	ax25_address dst_c;
	150
	151	if ((ourskb = skb_copy(skb, GFP_ATOMIC)) == NULL) {
	152	kfree_skb(skb);
	153	goto put;
	154	}
	155
	156	if (skb->sk != NULL)
	157	skb_set_owner_w(ourskb, skb->sk);
	158
	159	kfree_skb(skb);
	160	/* dl9sau: bugfix
	161	* after kfree_skb(), dst and src which were pointer
	162	* to bp which is part of skb->data would not be valid
	163	* anymore hope that after skb_pull(ourskb, ..) our
	164	* dsc_c and src_c will not become invalid
	165	*/
	166	bp = ourskb->data;
	167	dst_c = (ax25_address )(bp + 1);
	168	src_c = (ax25_address )(bp + 8);
	169
	170	skb_pull(ourskb, AX25_HEADER_LEN - 1); /* Keep PID */
c1d2bbe1	171	skb_reset_network_header(ourskb);
1da177e4 LT	172
1da177e4 LT	173	ax25=ax25_send_frame(
528930b9 YH	174	ourskb,
528930b9 YH	175	ax25_dev->values[AX25_VALUES_PACLEN],
1da177e4	176	&src_c,
006f68b8	177	&dst_c, digipeat, dev);
1da177e4 LT	178	if (ax25) {
	179	ax25_cb_put(ax25);
	180	}
	181	goto put;
	182	}
	183	}
	184
528930b9 YH	185	bp[7] &= ~AX25_CBIT;
	186	bp[7] &= ~AX25_EBIT;
	187	bp[7] \|= AX25_SSSID_SPARE;
1da177e4	188
528930b9 YH	189	bp[14] &= ~AX25_CBIT;
	190	bp[14] \|= AX25_EBIT;
	191	bp[14] \|= AX25_SSSID_SPARE;
1da177e4 LT	192
	193	skb_pull(skb, AX25_KISS_HEADER_LEN);
	194
006f68b8	195	if (digipeat != NULL) {
53744a4a	196	if ((ourskb = ax25_rt_build_path(skb, src, dst, route->digipeat)) == NULL)
1da177e4	197	goto put;
1da177e4 LT	198
	199	skb = ourskb;
	200	}
	201
29c4be51	202	ax25_queue_xmit(skb, dev);
1da177e4 LT	203
1da177e4 LT	204	put:
1da177e4	205
63530aba	206	ax25_route_lock_unuse();
1d5da757	207	return NETDEV_TX_OK;
3b6a94be EB	208	}
3b6a94be EB	209
1da177e4 LT	210	#else /* INET */
1da177e4 LT	211
46d4e47a EB	212	static int ax25_hard_header(struct sk_buff skb, struct net_device dev,
	213	unsigned short type, const void *daddr,
	214	const void *saddr, unsigned int len)
1da177e4 LT	215	{
	216	return -AX25_HEADER_LEN;
	217	}
	218
787fb2bd	219	netdev_tx_t ax25_ip_xmit(struct sk_buff *skb)
3b6a94be	220	{
1d5da757 EB	221	kfree_skb(skb);
1d5da757 EB	222	return NETDEV_TX_OK;
3b6a94be	223	}
1da177e4 LT	224	#endif
1da177e4 LT	225
ea47781c WB	226	static bool ax25_validate_header(const char *header, unsigned int len)
	227	{
	228	ax25_digi digi;
	229
	230	if (!len)
	231	return false;
	232
	233	if (header[0])
	234	return true;
	235
	236	return ax25_addr_parse(header + 1, len - 1, NULL, NULL, &digi, NULL,
	237	NULL);
	238	}
	239
3b04ddde SH	240	const struct header_ops ax25_header_ops = {
3b04ddde SH	241	.create = ax25_hard_header,
ea47781c	242	.validate = ax25_validate_header,
3b04ddde SH	243	};
3b04ddde SH	244
3b04ddde	245	EXPORT_SYMBOL(ax25_header_ops);
1d5da757	246	EXPORT_SYMBOL(ax25_ip_xmit);