[GitHub/mt8127/android_kernel_alcatel_ttab.git] / net / ax25 / ax25_in.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) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
 * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
 * Copyright (C) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de)
 */
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.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/skbuff.h>
#include <linux/netfilter.h>
#include <net/sock.h>
#include <net/tcp_states.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>

/*
 *	Given a fragment, queue it on the fragment queue and if the fragment
 *	is complete, send it back to ax25_rx_iframe.
 */
static int ax25_rx_fragment(ax25_cb *ax25, struct sk_buff *skb)
{
	struct sk_buff *skbn, *skbo;

	if (ax25->fragno != 0) {
		if (!(*skb->data & AX25_SEG_FIRST)) {
			if ((ax25->fragno - 1) == (*skb->data & AX25_SEG_REM)) {
				/* Enqueue fragment */
				ax25->fragno = *skb->data & AX25_SEG_REM;
				skb_pull(skb, 1);	/* skip fragno */
				ax25->fraglen += skb->len;
				skb_queue_tail(&ax25->frag_queue, skb);

				/* Last fragment received ? */
				if (ax25->fragno == 0) {
					skbn = alloc_skb(AX25_MAX_HEADER_LEN +
							 ax25->fraglen,
							 GFP_ATOMIC);
					if (!skbn) {
						skb_queue_purge(&ax25->frag_queue);
						return 1;
					}

					skb_reserve(skbn, AX25_MAX_HEADER_LEN);

					skbn->dev   = ax25->ax25_dev->dev;
					skb_reset_network_header(skbn);
					skb_reset_transport_header(skbn);

					/* Copy data from the fragments */
					while ((skbo = skb_dequeue(&ax25->frag_queue)) != NULL) {
						skb_copy_from_linear_data(skbo,
							  skb_put(skbn, skbo->len),
									  skbo->len);
						kfree_skb(skbo);
					}

					ax25->fraglen = 0;

					if (ax25_rx_iframe(ax25, skbn) == 0)
						kfree_skb(skbn);
				}

				return 1;
			}
		}
	} else {
		/* First fragment received */
		if (*skb->data & AX25_SEG_FIRST) {
			skb_queue_purge(&ax25->frag_queue);
			ax25->fragno = *skb->data & AX25_SEG_REM;
			skb_pull(skb, 1);		/* skip fragno */
			ax25->fraglen = skb->len;
			skb_queue_tail(&ax25->frag_queue, skb);
			return 1;
		}
	}

	return 0;
}

/*
 *	This is where all valid I frames are sent to, to be dispatched to
 *	whichever protocol requires them.
 */
int ax25_rx_iframe(ax25_cb *ax25, struct sk_buff *skb)
{
	int (*func)(struct sk_buff *, ax25_cb *);
	unsigned char pid;
	int queued = 0;

	if (skb == NULL) return 0;

	ax25_start_idletimer(ax25);

	pid = *skb->data;

	if (pid == AX25_P_IP) {
		/* working around a TCP bug to keep additional listeners
		 * happy. TCP re-uses the buffer and destroys the original
		 * content.
		 */
		struct sk_buff *skbn = skb_copy(skb, GFP_ATOMIC);
		if (skbn != NULL) {
			kfree_skb(skb);
			skb = skbn;
		}

		skb_pull(skb, 1);	/* Remove PID */
		skb->mac_header = skb->network_header;
		skb_reset_network_header(skb);
		skb->dev      = ax25->ax25_dev->dev;
		skb->pkt_type = PACKET_HOST;
		skb->protocol = htons(ETH_P_IP);
		netif_rx(skb);
		return 1;
	}
	if (pid == AX25_P_SEGMENT) {
		skb_pull(skb, 1);	/* Remove PID */
		return ax25_rx_fragment(ax25, skb);
	}

	if ((func = ax25_protocol_function(pid)) != NULL) {
		skb_pull(skb, 1);	/* Remove PID */
		return (*func)(skb, ax25);
	}

	if (ax25->sk != NULL && ax25->ax25_dev->values[AX25_VALUES_CONMODE] == 2) {
		if ((!ax25->pidincl && ax25->sk->sk_protocol == pid) ||
		    ax25->pidincl) {
			if (sock_queue_rcv_skb(ax25->sk, skb) == 0)
				queued = 1;
			else
				ax25->condition |= AX25_COND_OWN_RX_BUSY;
		}
	}

	return queued;
}

/*
 *	Higher level upcall for a LAPB frame
 */
static int ax25_process_rx_frame(ax25_cb *ax25, struct sk_buff *skb, int type, int dama)
{
	int queued = 0;

	if (ax25->state == AX25_STATE_0)
		return 0;

	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
	case AX25_PROTO_STD_SIMPLEX:
	case AX25_PROTO_STD_DUPLEX:
		queued = ax25_std_frame_in(ax25, skb, type);
		break;

#ifdef CONFIG_AX25_DAMA_SLAVE
	case AX25_PROTO_DAMA_SLAVE:
		if (dama || ax25->ax25_dev->dama.slave)
			queued = ax25_ds_frame_in(ax25, skb, type);
		else
			queued = ax25_std_frame_in(ax25, skb, type);
		break;
#endif
	}

	return queued;
}

static int ax25_rcv(struct sk_buff *skb, struct net_device *dev,
	ax25_address *dev_addr, struct packet_type *ptype)
{
	ax25_address src, dest, *next_digi = NULL;
	int type = 0, mine = 0, dama;
	struct sock *make, *sk;
	ax25_digi dp, reverse_dp;
	ax25_cb *ax25;
	ax25_dev *ax25_dev;

	/*
	 *	Process the AX.25/LAPB frame.
	 */

	skb_reset_transport_header(skb);

	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) {
		kfree_skb(skb);
		return 0;
	}

	/*
	 *	Parse the address header.
	 */

	if (ax25_addr_parse(skb->data, skb->len, &src, &dest, &dp, &type, &dama) == NULL) {
		kfree_skb(skb);
		return 0;
	}

	/*
	 *	Ours perhaps ?
	 */
	if (dp.lastrepeat + 1 < dp.ndigi)		/* Not yet digipeated completely */
		next_digi = &dp.calls[dp.lastrepeat + 1];

	/*
	 *	Pull of the AX.25 headers leaving the CTRL/PID bytes
	 */
	skb_pull(skb, ax25_addr_size(&dp));

	/* For our port addresses ? */
	if (ax25cmp(&dest, dev_addr) == 0 && dp.lastrepeat + 1 == dp.ndigi)
		mine = 1;

	/* Also match on any registered callsign from L3/4 */
	if (!mine && ax25_listen_mine(&dest, dev) && dp.lastrepeat + 1 == dp.ndigi)
		mine = 1;

	/* UI frame - bypass LAPB processing */
	if ((*skb->data & ~0x10) == AX25_UI && dp.lastrepeat + 1 == dp.ndigi) {
		skb_set_transport_header(skb, 2); /* skip control and pid */

		ax25_send_to_raw(&dest, skb, skb->data[1]);

		if (!mine && ax25cmp(&dest, (ax25_address *)dev->broadcast) != 0) {
			kfree_skb(skb);
			return 0;
		}

		/* Now we are pointing at the pid byte */
		switch (skb->data[1]) {
		case AX25_P_IP:
			skb_pull(skb,2);		/* drop PID/CTRL */
			skb_reset_transport_header(skb);
			skb_reset_network_header(skb);
			skb->dev      = dev;
			skb->pkt_type = PACKET_HOST;
			skb->protocol = htons(ETH_P_IP);
			netif_rx(skb);
			break;

		case AX25_P_ARP:
			skb_pull(skb,2);
			skb_reset_transport_header(skb);
			skb_reset_network_header(skb);
			skb->dev      = dev;
			skb->pkt_type = PACKET_HOST;
			skb->protocol = htons(ETH_P_ARP);
			netif_rx(skb);
			break;
		case AX25_P_TEXT:
			/* Now find a suitable dgram socket */
			sk = ax25_get_socket(&dest, &src, SOCK_DGRAM);
			if (sk != NULL) {
				bh_lock_sock(sk);
				if (atomic_read(&sk->sk_rmem_alloc) >=
				    sk->sk_rcvbuf) {
					kfree_skb(skb);
				} else {
					/*
					 *	Remove the control and PID.
					 */
					skb_pull(skb, 2);
					if (sock_queue_rcv_skb(sk, skb) != 0)
						kfree_skb(skb);
				}
				bh_unlock_sock(sk);
				sock_put(sk);
			} else {
				kfree_skb(skb);
			}
			break;

		default:
			kfree_skb(skb);	/* Will scan SOCK_AX25 RAW sockets */
			break;
		}

		return 0;
	}

	/*
	 *	Is connected mode supported on this device ?
	 *	If not, should we DM the incoming frame (except DMs) or
	 *	silently ignore them. For now we stay quiet.
	 */
	if (ax25_dev->values[AX25_VALUES_CONMODE] == 0) {
		kfree_skb(skb);
		return 0;
	}

	/* LAPB */

	/* AX.25 state 1-4 */

	ax25_digi_invert(&dp, &reverse_dp);

	if ((ax25 = ax25_find_cb(&dest, &src, &reverse_dp, dev)) != NULL) {
		/*
		 *	Process the frame. If it is queued up internally it
		 *	returns one otherwise we free it immediately. This
		 *	routine itself wakes the user context layers so we do
		 *	no further work
		 */
		if (ax25_process_rx_frame(ax25, skb, type, dama) == 0)
			kfree_skb(skb);

		ax25_cb_put(ax25);
		return 0;
	}

	/* AX.25 state 0 (disconnected) */

	/* a) received not a SABM(E) */

	if ((*skb->data & ~AX25_PF) != AX25_SABM &&
	    (*skb->data & ~AX25_PF) != AX25_SABME) {
		/*
		 *	Never reply to a DM. Also ignore any connects for
		 *	addresses that are not our interfaces and not a socket.
		 */
		if ((*skb->data & ~AX25_PF) != AX25_DM && mine)
			ax25_return_dm(dev, &src, &dest, &dp);

		kfree_skb(skb);
		return 0;
	}

	/* b) received SABM(E) */

	if (dp.lastrepeat + 1 == dp.ndigi)
		sk = ax25_find_listener(&dest, 0, dev, SOCK_SEQPACKET);
	else
		sk = ax25_find_listener(next_digi, 1, dev, SOCK_SEQPACKET);

	if (sk != NULL) {
		bh_lock_sock(sk);
		if (sk_acceptq_is_full(sk) ||
		    (make = ax25_make_new(sk, ax25_dev)) == NULL) {
			if (mine)
				ax25_return_dm(dev, &src, &dest, &dp);
			kfree_skb(skb);
			bh_unlock_sock(sk);
			sock_put(sk);

			return 0;
		}

		ax25 = ax25_sk(make);
		skb_set_owner_r(skb, make);
		skb_queue_head(&sk->sk_receive_queue, skb);

		make->sk_state = TCP_ESTABLISHED;

		sk->sk_ack_backlog++;
		bh_unlock_sock(sk);
	} else {
		if (!mine) {
			kfree_skb(skb);
			return 0;
		}

		if ((ax25 = ax25_create_cb()) == NULL) {
			ax25_return_dm(dev, &src, &dest, &dp);
			kfree_skb(skb);
			return 0;
		}

		ax25_fillin_cb(ax25, ax25_dev);
	}

	ax25->source_addr = dest;
	ax25->dest_addr   = src;

	/*
	 *	Sort out any digipeated paths.
	 */
	if (dp.ndigi && !ax25->digipeat &&
	    (ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
		kfree_skb(skb);
		ax25_destroy_socket(ax25);
		if (sk)
			sock_put(sk);
		return 0;
	}

	if (dp.ndigi == 0) {
		kfree(ax25->digipeat);
		ax25->digipeat = NULL;
	} else {
		/* Reverse the source SABM's path */
		memcpy(ax25->digipeat, &reverse_dp, sizeof(ax25_digi));
	}

	if ((*skb->data & ~AX25_PF) == AX25_SABME) {
		ax25->modulus = AX25_EMODULUS;
		ax25->window  = ax25_dev->values[AX25_VALUES_EWINDOW];
	} else {
		ax25->modulus = AX25_MODULUS;
		ax25->window  = ax25_dev->values[AX25_VALUES_WINDOW];
	}

	ax25_send_control(ax25, AX25_UA, AX25_POLLON, AX25_RESPONSE);

#ifdef CONFIG_AX25_DAMA_SLAVE
	if (dama && ax25->ax25_dev->values[AX25_VALUES_PROTOCOL] == AX25_PROTO_DAMA_SLAVE)
		ax25_dama_on(ax25);
#endif

	ax25->state = AX25_STATE_3;

	ax25_cb_add(ax25);

	ax25_start_heartbeat(ax25);
	ax25_start_t3timer(ax25);
	ax25_start_idletimer(ax25);

	if (sk) {
		if (!sock_flag(sk, SOCK_DEAD))
			sk->sk_data_ready(sk, skb->len);
		sock_put(sk);
	} else
		kfree_skb(skb);

	return 0;
}

/*
 *	Receive an AX.25 frame via a SLIP interface.
 */
int ax25_kiss_rcv(struct sk_buff *skb, struct net_device *dev,
		  struct packet_type *ptype, struct net_device *orig_dev)
{
	skb->sk = NULL;		/* Initially we don't know who it's for */
	skb->destructor = NULL;	/* Who initializes this, dammit?! */

	if (dev_net(dev) != &init_net) {
		kfree_skb(skb);
		return 0;
	}

	if ((*skb->data & 0x0F) != 0) {
		kfree_skb(skb);	/* Not a KISS data frame */
		return 0;
	}

	skb_pull(skb, AX25_KISS_HEADER_LEN);	/* Remove the KISS byte */

	return ax25_rcv(skb, dev, (ax25_address *)dev->dev_addr, ptype);
}
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) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
	8	* Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
	9	* Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
	10	* Copyright (C) Hans-Joachim Hetscher DD8NE (dd8ne@bnv-bamberg.de)
	11	*/
1da177e4 LT	12	#include <linux/errno.h>
	13	#include <linux/types.h>
	14	#include <linux/socket.h>
	15	#include <linux/in.h>
	16	#include <linux/kernel.h>
1da177e4 LT	17	#include <linux/timer.h>
	18	#include <linux/string.h>
	19	#include <linux/sockios.h>
	20	#include <linux/net.h>
	21	#include <net/ax25.h>
	22	#include <linux/inet.h>
	23	#include <linux/netdevice.h>
	24	#include <linux/skbuff.h>
	25	#include <linux/netfilter.h>
	26	#include <net/sock.h>
c752f073	27	#include <net/tcp_states.h>
1da177e4 LT	28	#include <asm/uaccess.h>
	29	#include <asm/system.h>
	30	#include <linux/fcntl.h>
	31	#include <linux/mm.h>
	32	#include <linux/interrupt.h>
	33
	34	/*
	35	* Given a fragment, queue it on the fragment queue and if the fragment
	36	* is complete, send it back to ax25_rx_iframe.
	37	*/
	38	static int ax25_rx_fragment(ax25_cb ax25, struct sk_buff skb)
	39	{
	40	struct sk_buff skbn, skbo;
	41
	42	if (ax25->fragno != 0) {
	43	if (!(*skb->data & AX25_SEG_FIRST)) {
	44	if ((ax25->fragno - 1) == (*skb->data & AX25_SEG_REM)) {
	45	/* Enqueue fragment */
	46	ax25->fragno = *skb->data & AX25_SEG_REM;
	47	skb_pull(skb, 1); /* skip fragno */
	48	ax25->fraglen += skb->len;
	49	skb_queue_tail(&ax25->frag_queue, skb);
	50
	51	/* Last fragment received ? */
	52	if (ax25->fragno == 0) {
	53	skbn = alloc_skb(AX25_MAX_HEADER_LEN +
	54	ax25->fraglen,
	55	GFP_ATOMIC);
	56	if (!skbn) {
	57	skb_queue_purge(&ax25->frag_queue);
	58	return 1;
	59	}
	60
	61	skb_reserve(skbn, AX25_MAX_HEADER_LEN);
	62
	63	skbn->dev = ax25->ax25_dev->dev;
c1d2bbe1	64	skb_reset_network_header(skbn);
badff6d0	65	skb_reset_transport_header(skbn);
1da177e4 LT	66
	67	/* Copy data from the fragments */
	68	while ((skbo = skb_dequeue(&ax25->frag_queue)) != NULL) {
1a4e2d09 ACM	69	skb_copy_from_linear_data(skbo,
	70	skb_put(skbn, skbo->len),
	71	skbo->len);
1da177e4 LT	72	kfree_skb(skbo);
	73	}
	74
	75	ax25->fraglen = 0;
	76
	77	if (ax25_rx_iframe(ax25, skbn) == 0)
	78	kfree_skb(skbn);
	79	}
	80
	81	return 1;
	82	}
	83	}
	84	} else {
	85	/* First fragment received */
	86	if (*skb->data & AX25_SEG_FIRST) {
	87	skb_queue_purge(&ax25->frag_queue);
	88	ax25->fragno = *skb->data & AX25_SEG_REM;
	89	skb_pull(skb, 1); /* skip fragno */
	90	ax25->fraglen = skb->len;
	91	skb_queue_tail(&ax25->frag_queue, skb);
	92	return 1;
	93	}
	94	}
	95
	96	return 0;
	97	}
	98
	99	/*
	100	* This is where all valid I frames are sent to, to be dispatched to
	101	* whichever protocol requires them.
	102	*/
	103	int ax25_rx_iframe(ax25_cb ax25, struct sk_buff skb)
	104	{
	105	int (func)(struct sk_buff , ax25_cb *);
1da177e4	106	unsigned char pid;
bde3445c	107	int queued = 0;
1da177e4 LT	108
	109	if (skb == NULL) return 0;
	110
	111	ax25_start_idletimer(ax25);
	112
	113	pid = *skb->data;
	114
1da177e4 LT	115	if (pid == AX25_P_IP) {
	116	/* working around a TCP bug to keep additional listeners
	117	* happy. TCP re-uses the buffer and destroys the original
	118	* content.
	119	*/
	120	struct sk_buff *skbn = skb_copy(skb, GFP_ATOMIC);
	121	if (skbn != NULL) {
	122	kfree_skb(skb);
	123	skb = skbn;
	124	}
	125
	126	skb_pull(skb, 1); /* Remove PID */
c6e6ca71	127	skb->mac_header = skb->network_header;
c1d2bbe1	128	skb_reset_network_header(skb);
1da177e4 LT	129	skb->dev = ax25->ax25_dev->dev;
	130	skb->pkt_type = PACKET_HOST;
	131	skb->protocol = htons(ETH_P_IP);
98a82feb	132	netif_rx(skb);
1da177e4 LT	133	return 1;
1da177e4 LT	134	}
1da177e4 LT	135	if (pid == AX25_P_SEGMENT) {
	136	skb_pull(skb, 1); /* Remove PID */
	137	return ax25_rx_fragment(ax25, skb);
	138	}
	139
	140	if ((func = ax25_protocol_function(pid)) != NULL) {
	141	skb_pull(skb, 1); /* Remove PID */
	142	return (*func)(skb, ax25);
	143	}
	144
	145	if (ax25->sk != NULL && ax25->ax25_dev->values[AX25_VALUES_CONMODE] == 2) {
	146	if ((!ax25->pidincl && ax25->sk->sk_protocol == pid) \|\|
	147	ax25->pidincl) {
	148	if (sock_queue_rcv_skb(ax25->sk, skb) == 0)
	149	queued = 1;
	150	else
	151	ax25->condition \|= AX25_COND_OWN_RX_BUSY;
	152	}
	153	}
	154
	155	return queued;
	156	}
	157
	158	/*
	159	* Higher level upcall for a LAPB frame
	160	*/
	161	static int ax25_process_rx_frame(ax25_cb ax25, struct sk_buff skb, int type, int dama)
	162	{
	163	int queued = 0;
	164
	165	if (ax25->state == AX25_STATE_0)
	166	return 0;
	167
	168	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
	169	case AX25_PROTO_STD_SIMPLEX:
	170	case AX25_PROTO_STD_DUPLEX:
	171	queued = ax25_std_frame_in(ax25, skb, type);
	172	break;
	173
	174	#ifdef CONFIG_AX25_DAMA_SLAVE
	175	case AX25_PROTO_DAMA_SLAVE:
	176	if (dama \|\| ax25->ax25_dev->dama.slave)
	177	queued = ax25_ds_frame_in(ax25, skb, type);
	178	else
	179	queued = ax25_std_frame_in(ax25, skb, type);
	180	break;
	181	#endif
	182	}
	183
	184	return queued;
	185	}
	186
	187	static int ax25_rcv(struct sk_buff skb, struct net_device dev,
	188	ax25_address dev_addr, struct packet_type ptype)
	189	{
	190	ax25_address src, dest, *next_digi = NULL;
	191	int type = 0, mine = 0, dama;
	192	struct sock make, sk;
	193	ax25_digi dp, reverse_dp;
	194	ax25_cb *ax25;
	195	ax25_dev *ax25_dev;
	196
	197	/*
	198	* Process the AX.25/LAPB frame.
199	*/
200
badff6d0	201	skb_reset_transport_header(skb);
1da177e4 LT	202
	203	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) {
	204	kfree_skb(skb);
	205	return 0;
	206	}
	207
	208	/*
	209	* Parse the address header.
	210	*/
	211
	212	if (ax25_addr_parse(skb->data, skb->len, &src, &dest, &dp, &type, &dama) == NULL) {
	213	kfree_skb(skb);
	214	return 0;
	215	}
	216
	217	/*
	218	* Ours perhaps ?
	219	*/
	220	if (dp.lastrepeat + 1 < dp.ndigi) /* Not yet digipeated completely */
	221	next_digi = &dp.calls[dp.lastrepeat + 1];
	222
	223	/*
	224	* Pull of the AX.25 headers leaving the CTRL/PID bytes
	225	*/
	226	skb_pull(skb, ax25_addr_size(&dp));
	227
	228	/* For our port addresses ? */
	229	if (ax25cmp(&dest, dev_addr) == 0 && dp.lastrepeat + 1 == dp.ndigi)
	230	mine = 1;
	231
	232	/* Also match on any registered callsign from L3/4 */
	233	if (!mine && ax25_listen_mine(&dest, dev) && dp.lastrepeat + 1 == dp.ndigi)
	234	mine = 1;
	235
	236	/* UI frame - bypass LAPB processing */
	237	if ((*skb->data & ~0x10) == AX25_UI && dp.lastrepeat + 1 == dp.ndigi) {
967b05f6	238	skb_set_transport_header(skb, 2); /* skip control and pid */
1da177e4 LT	239
	240	ax25_send_to_raw(&dest, skb, skb->data[1]);
	241
	242	if (!mine && ax25cmp(&dest, (ax25_address *)dev->broadcast) != 0) {
	243	kfree_skb(skb);
	244	return 0;
	245	}
	246
	247	/* Now we are pointing at the pid byte */
	248	switch (skb->data[1]) {
1da177e4 LT	249	case AX25_P_IP:
1da177e4 LT	250	skb_pull(skb,2); /* drop PID/CTRL */
badff6d0	251	skb_reset_transport_header(skb);
c1d2bbe1	252	skb_reset_network_header(skb);
1da177e4 LT	253	skb->dev = dev;
	254	skb->pkt_type = PACKET_HOST;
	255	skb->protocol = htons(ETH_P_IP);
98a82feb	256	netif_rx(skb);
1da177e4 LT	257	break;
	258
	259	case AX25_P_ARP:
	260	skb_pull(skb,2);
badff6d0	261	skb_reset_transport_header(skb);
c1d2bbe1	262	skb_reset_network_header(skb);
1da177e4 LT	263	skb->dev = dev;
	264	skb->pkt_type = PACKET_HOST;
	265	skb->protocol = htons(ETH_P_ARP);
98a82feb	266	netif_rx(skb);
1da177e4	267	break;
1da177e4 LT	268	case AX25_P_TEXT:
	269	/* Now find a suitable dgram socket */
	270	sk = ax25_get_socket(&dest, &src, SOCK_DGRAM);
	271	if (sk != NULL) {
	272	bh_lock_sock(sk);
	273	if (atomic_read(&sk->sk_rmem_alloc) >=
	274	sk->sk_rcvbuf) {
	275	kfree_skb(skb);
	276	} else {
	277	/*
	278	* Remove the control and PID.
	279	*/
	280	skb_pull(skb, 2);
	281	if (sock_queue_rcv_skb(sk, skb) != 0)
	282	kfree_skb(skb);
	283	}
	284	bh_unlock_sock(sk);
	285	sock_put(sk);
	286	} else {
	287	kfree_skb(skb);
	288	}
	289	break;
	290
	291	default:
	292	kfree_skb(skb); /* Will scan SOCK_AX25 RAW sockets */
	293	break;
	294	}
	295
	296	return 0;
	297	}
	298
	299	/*
	300	* Is connected mode supported on this device ?
	301	* If not, should we DM the incoming frame (except DMs) or
	302	* silently ignore them. For now we stay quiet.
	303	*/
	304	if (ax25_dev->values[AX25_VALUES_CONMODE] == 0) {
	305	kfree_skb(skb);
	306	return 0;
	307	}
	308
	309	/* LAPB */
	310
	311	/* AX.25 state 1-4 */
	312
	313	ax25_digi_invert(&dp, &reverse_dp);
	314
	315	if ((ax25 = ax25_find_cb(&dest, &src, &reverse_dp, dev)) != NULL) {
	316	/*
	317	* Process the frame. If it is queued up internally it
	318	* returns one otherwise we free it immediately. This
	319	* routine itself wakes the user context layers so we do
	320	* no further work
	321	*/
	322	if (ax25_process_rx_frame(ax25, skb, type, dama) == 0)
	323	kfree_skb(skb);
	324
	325	ax25_cb_put(ax25);
	326	return 0;
	327	}
	328
	329	/* AX.25 state 0 (disconnected) */
	330
	331	/* a) received not a SABM(E) */
332
333	if ((*skb->data & ~AX25_PF) != AX25_SABM &&
334	(*skb->data & ~AX25_PF) != AX25_SABME) {
335	/*
336	* Never reply to a DM. Also ignore any connects for
337	* addresses that are not our interfaces and not a socket.
338	*/
339	if ((*skb->data & ~AX25_PF) != AX25_DM && mine)
340	ax25_return_dm(dev, &src, &dest, &dp);
341
342	kfree_skb(skb);
343	return 0;
344	}
345
346	/* b) received SABM(E) */
347
348	if (dp.lastrepeat + 1 == dp.ndigi)
349	sk = ax25_find_listener(&dest, 0, dev, SOCK_SEQPACKET);
350	else
351	sk = ax25_find_listener(next_digi, 1, dev, SOCK_SEQPACKET);
352
353	if (sk != NULL) {
354	bh_lock_sock(sk);
355	if (sk_acceptq_is_full(sk) \|\|
356	(make = ax25_make_new(sk, ax25_dev)) == NULL) {
357	if (mine)
358	ax25_return_dm(dev, &src, &dest, &dp);
359	kfree_skb(skb);
360	bh_unlock_sock(sk);
361	sock_put(sk);
362
363	return 0;
364	}
365
366	ax25 = ax25_sk(make);
367	skb_set_owner_r(skb, make);
368	skb_queue_head(&sk->sk_receive_queue, skb);
369
370	make->sk_state = TCP_ESTABLISHED;
371
372	sk->sk_ack_backlog++;
373	bh_unlock_sock(sk);
374	} else {
375	if (!mine) {
376	kfree_skb(skb);
377	return 0;
378	}
379
380	if ((ax25 = ax25_create_cb()) == NULL) {
381	ax25_return_dm(dev, &src, &dest, &dp);
382	kfree_skb(skb);
383	return 0;
384	}
385
386	ax25_fillin_cb(ax25, ax25_dev);
387	}
388
389	ax25->source_addr = dest;
390	ax25->dest_addr = src;
391
392	/*
393	* Sort out any digipeated paths.
394	*/
395	if (dp.ndigi && !ax25->digipeat &&
396	(ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
397	kfree_skb(skb);
398	ax25_destroy_socket(ax25);
399	if (sk)
400	sock_put(sk);
401	return 0;
402	}
403
404	if (dp.ndigi == 0) {
a51482bd JJ	405	kfree(ax25->digipeat);
a51482bd JJ	406	ax25->digipeat = NULL;
1da177e4 LT	407	} else {
	408	/* Reverse the source SABM's path */
	409	memcpy(ax25->digipeat, &reverse_dp, sizeof(ax25_digi));
	410	}
	411
	412	if ((*skb->data & ~AX25_PF) == AX25_SABME) {
	413	ax25->modulus = AX25_EMODULUS;
	414	ax25->window = ax25_dev->values[AX25_VALUES_EWINDOW];
	415	} else {
	416	ax25->modulus = AX25_MODULUS;
	417	ax25->window = ax25_dev->values[AX25_VALUES_WINDOW];
	418	}
	419
	420	ax25_send_control(ax25, AX25_UA, AX25_POLLON, AX25_RESPONSE);
	421
	422	#ifdef CONFIG_AX25_DAMA_SLAVE
	423	if (dama && ax25->ax25_dev->values[AX25_VALUES_PROTOCOL] == AX25_PROTO_DAMA_SLAVE)
	424	ax25_dama_on(ax25);
	425	#endif
	426
	427	ax25->state = AX25_STATE_3;
	428
	429	ax25_cb_add(ax25);
	430
	431	ax25_start_heartbeat(ax25);
	432	ax25_start_t3timer(ax25);
	433	ax25_start_idletimer(ax25);
	434
	435	if (sk) {
	436	if (!sock_flag(sk, SOCK_DEAD))
	437	sk->sk_data_ready(sk, skb->len);
	438	sock_put(sk);
	439	} else
	440	kfree_skb(skb);
	441
	442	return 0;
	443	}
	444
	445	/*
	446	* Receive an AX.25 frame via a SLIP interface.
	447	*/
	448	int ax25_kiss_rcv(struct sk_buff skb, struct net_device dev,
f2ccd8fa	449	struct packet_type ptype, struct net_device orig_dev)
1da177e4 LT	450	{
	451	skb->sk = NULL; /* Initially we don't know who it's for */
	452	skb->destructor = NULL; /* Who initializes this, dammit?! */
	453
c346dca1	454	if (dev_net(dev) != &init_net) {
e730c155 EB	455	kfree_skb(skb);
	456	return 0;
	457	}
	458
1da177e4 LT	459	if ((*skb->data & 0x0F) != 0) {
	460	kfree_skb(skb); /* Not a KISS data frame */
	461	return 0;
	462	}
	463
	464	skb_pull(skb, AX25_KISS_HEADER_LEN); /* Remove the KISS byte */
	465
	466	return ax25_rcv(skb, dev, (ax25_address *)dev->dev_addr, ptype);
	467	}