1 files changed, 383 insertions, 0 deletions
diff --git a/net/ax25/ax25_out.c b/net/ax25/ax25_out.c
new file mode 100644
index 00000000000..3475a3ac934
--- /dev/null
+++ b/net/ax25/ax25_out.c
@@ -0,0 +1,383 @@
+/*
+ * 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)
+ */
+#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/spinlock.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 <asm/uaccess.h>
+#include <asm/system.h>
+#include <linux/fcntl.h>
+#include <linux/mm.h>
+#include <linux/interrupt.h>
+
+static DEFINE_SPINLOCK(ax25_frag_lock);
+
+ax25_cb *ax25_send_frame(struct sk_buff *skb, int paclen, ax25_address *src, ax25_address *dest, ax25_digi *digi, struct net_device *dev)
+{
+	ax25_dev *ax25_dev;
+	ax25_cb *ax25;
+
+	/*
+	 * Take the default packet length for the device if zero is
+	 * specified.
+	 */
+	if (paclen == 0) {
+		if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
+			return NULL;
+
+		paclen = ax25_dev->values[AX25_VALUES_PACLEN];
+	}
+
+	/*
+	 * Look for an existing connection.
+	 */
+	if ((ax25 = ax25_find_cb(src, dest, digi, dev)) != NULL) {
+		ax25_output(ax25, paclen, skb);
+		return ax25;		/* It already existed */
+	}
+
+	if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
+		return NULL;
+
+	if ((ax25 = ax25_create_cb()) == NULL)
+		return NULL;
+
+	ax25_fillin_cb(ax25, ax25_dev);
+
+	ax25->source_addr = *src;
+	ax25->dest_addr   = *dest;
+
+	if (digi != NULL) {
+		if ((ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
+			ax25_cb_put(ax25);
+			return NULL;
+		}
+		memcpy(ax25->digipeat, digi, sizeof(ax25_digi));
+	}
+
+	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
+	case AX25_PROTO_STD_SIMPLEX:
+	case AX25_PROTO_STD_DUPLEX:
+		ax25_std_establish_data_link(ax25);
+		break;
+
+#ifdef CONFIG_AX25_DAMA_SLAVE
+	case AX25_PROTO_DAMA_SLAVE:
+		if (ax25_dev->dama.slave)
+			ax25_ds_establish_data_link(ax25);
+		else
+			ax25_std_establish_data_link(ax25);
+		break;
+#endif
+	}
+
+	ax25_cb_add(ax25);
+
+	ax25->state = AX25_STATE_1;
+
+	ax25_start_heartbeat(ax25);
+
+	ax25_output(ax25, paclen, skb);
+
+	return ax25;			/* We had to create it */
+}
+
+/*
+ *	All outgoing AX.25 I frames pass via this routine. Therefore this is
+ *	where the fragmentation of frames takes place. If fragment is set to
+ *	zero then we are not allowed to do fragmentation, even if the frame
+ *	is too large.
+ */
+void ax25_output(ax25_cb *ax25, int paclen, struct sk_buff *skb)
+{
+	struct sk_buff *skbn;
+	unsigned char *p;
+	int frontlen, len, fragno, ka9qfrag, first = 1;
+
+	if ((skb->len - 1) > paclen) {
+		if (*skb->data == AX25_P_TEXT) {
+			skb_pull(skb, 1); /* skip PID */
+			ka9qfrag = 0;
+		} else {
+			paclen -= 2;	/* Allow for fragment control info */
+			ka9qfrag = 1;
+		}
+
+		fragno = skb->len / paclen;
+		if (skb->len % paclen == 0) fragno--;
+
+		frontlen = skb_headroom(skb);	/* Address space + CTRL */
+
+		while (skb->len > 0) {
+			spin_lock_bh(&ax25_frag_lock);
+			if ((skbn = alloc_skb(paclen + 2 + frontlen, GFP_ATOMIC)) == NULL) {
+				spin_unlock_bh(&ax25_frag_lock);
+				printk(KERN_CRIT "AX.25: ax25_output - out of memory\n");
+				return;
+			}
+
+			if (skb->sk != NULL)
+				skb_set_owner_w(skbn, skb->sk);
+
+			spin_unlock_bh(&ax25_frag_lock);
+
+			len = (paclen > skb->len) ? skb->len : paclen;
+
+			if (ka9qfrag == 1) {
+				skb_reserve(skbn, frontlen + 2);
+				skbn->nh.raw = skbn->data + (skb->nh.raw - skb->data);
+				memcpy(skb_put(skbn, len), skb->data, len);
+				p = skb_push(skbn, 2);
+
+				*p++ = AX25_P_SEGMENT;
+
+				*p = fragno--;
+				if (first) {
+					*p |= AX25_SEG_FIRST;
+					first = 0;
+				}
+			} else {
+				skb_reserve(skbn, frontlen + 1);
+				skbn->nh.raw = skbn->data + (skb->nh.raw - skb->data);
+				memcpy(skb_put(skbn, len), skb->data, len);
+				p = skb_push(skbn, 1);
+				*p = AX25_P_TEXT;
+			}
+
+			skb_pull(skb, len);
+			skb_queue_tail(&ax25->write_queue, skbn); /* Throw it on the queue */
+		}
+
+		kfree_skb(skb);
+	} else {
+		skb_queue_tail(&ax25->write_queue, skb);	  /* Throw it on the queue */
+	}
+
+	switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
+	case AX25_PROTO_STD_SIMPLEX:
+	case AX25_PROTO_STD_DUPLEX:
+		ax25_kick(ax25);
+		break;
+
+#ifdef CONFIG_AX25_DAMA_SLAVE
+	/*
+	 * A DAMA slave is _required_ to work as normal AX.25L2V2
+	 * if no DAMA master is available.
+	 */
+	case AX25_PROTO_DAMA_SLAVE:
+		if (!ax25->ax25_dev->dama.slave) ax25_kick(ax25);
+		break;
+#endif
+	}
+}
+
+/*
+ *  This procedure is passed a buffer descriptor for an iframe. It builds
+ *  the rest of the control part of the frame and then writes it out.
+ */
+static void ax25_send_iframe(ax25_cb *ax25, struct sk_buff *skb, int poll_bit)
+{
+	unsigned char *frame;
+
+	if (skb == NULL)
+		return;
+
+	skb->nh.raw = skb->data;
+
+	if (ax25->modulus == AX25_MODULUS) {
+		frame = skb_push(skb, 1);
+
+		*frame = AX25_I;
+		*frame |= (poll_bit) ? AX25_PF : 0;
+		*frame |= (ax25->vr << 5);
+		*frame |= (ax25->vs << 1);
+	} else {
+		frame = skb_push(skb, 2);
+
+		frame[0] = AX25_I;
+		frame[0] |= (ax25->vs << 1);
+		frame[1] = (poll_bit) ? AX25_EPF : 0;
+		frame[1] |= (ax25->vr << 1);
+	}
+
+	ax25_start_idletimer(ax25);
+
+	ax25_transmit_buffer(ax25, skb, AX25_COMMAND);
+}
+
+void ax25_kick(ax25_cb *ax25)
+{
+	struct sk_buff *skb, *skbn;
+	int last = 1;
+	unsigned short start, end, next;
+
+	if (ax25->state != AX25_STATE_3 && ax25->state != AX25_STATE_4)
+		return;
+
+	if (ax25->condition & AX25_COND_PEER_RX_BUSY)
+		return;
+
+	if (skb_peek(&ax25->write_queue) == NULL)
+		return;
+
+	start = (skb_peek(&ax25->ack_queue) == NULL) ? ax25->va : ax25->vs;
+	end   = (ax25->va + ax25->window) % ax25->modulus;
+
+	if (start == end)
+		return;
+
+	ax25->vs = start;
+
+	/*
+	 * Transmit data until either we're out of data to send or
+	 * the window is full. Send a poll on the final I frame if
+	 * the window is filled.
+	 */
+
+	/*
+	 * Dequeue the frame and copy it.
+	 */
+	skb  = skb_dequeue(&ax25->write_queue);
+
+	do {
+		if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
+			skb_queue_head(&ax25->write_queue, skb);
+			break;
+		}
+
+		if (skb->sk != NULL)
+			skb_set_owner_w(skbn, skb->sk);
+
+		next = (ax25->vs + 1) % ax25->modulus;
+		last = (next == end);
+
+		/*
+		 * Transmit the frame copy.
+		 * bke 960114: do not set the Poll bit on the last frame
+		 * in DAMA mode.
+		 */
+		switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
+		case AX25_PROTO_STD_SIMPLEX:
+		case AX25_PROTO_STD_DUPLEX:
+			ax25_send_iframe(ax25, skbn, (last) ? AX25_POLLON : AX25_POLLOFF);
+			break;
+
+#ifdef CONFIG_AX25_DAMA_SLAVE
+		case AX25_PROTO_DAMA_SLAVE:
+			ax25_send_iframe(ax25, skbn, AX25_POLLOFF);
+			break;
+#endif
+		}
+
+		ax25->vs = next;
+
+		/*
+		 * Requeue the original data frame.
+		 */
+		skb_queue_tail(&ax25->ack_queue, skb);
+
+	} while (!last && (skb = skb_dequeue(&ax25->write_queue)) != NULL);
+
+	ax25->condition &= ~AX25_COND_ACK_PENDING;
+
+	if (!ax25_t1timer_running(ax25)) {
+		ax25_stop_t3timer(ax25);
+		ax25_calculate_t1(ax25);
+		ax25_start_t1timer(ax25);
+	}
+}
+
+void ax25_transmit_buffer(ax25_cb *ax25, struct sk_buff *skb, int type)
+{
+	struct sk_buff *skbn;
+	unsigned char *ptr;
+	int headroom;
+
+	if (ax25->ax25_dev == NULL) {
+		ax25_disconnect(ax25, ENETUNREACH);
+		return;
+	}
+
+	headroom = ax25_addr_size(ax25->digipeat);
+
+	if (skb_headroom(skb) < headroom) {
+		if ((skbn = skb_realloc_headroom(skb, headroom)) == NULL) {
+			printk(KERN_CRIT "AX.25: ax25_transmit_buffer - out of memory\n");
+			kfree_skb(skb);
+			return;
+		}
+
+		if (skb->sk != NULL)
+			skb_set_owner_w(skbn, skb->sk);
+
+		kfree_skb(skb);
+		skb = skbn;
+	}
+
+	ptr = skb_push(skb, headroom);
+
+	ax25_addr_build(ptr, &ax25->source_addr, &ax25->dest_addr, ax25->digipeat, type, ax25->modulus);
+
+	skb->dev = ax25->ax25_dev->dev;
+
+	ax25_queue_xmit(skb);
+}
+
+/*
+ *	A small shim to dev_queue_xmit to add the KISS control byte, and do
+ *	any packet forwarding in operation.
+ */
+void ax25_queue_xmit(struct sk_buff *skb)
+{
+	unsigned char *ptr;
+
+	skb->protocol = htons(ETH_P_AX25);
+	skb->dev      = ax25_fwd_dev(skb->dev);
+
+	ptr  = skb_push(skb, 1);
+	*ptr = 0x00;			/* KISS */
+
+	dev_queue_xmit(skb);
+}
+
+int ax25_check_iframes_acked(ax25_cb *ax25, unsigned short nr)
+{
+	if (ax25->vs == nr) {
+		ax25_frames_acked(ax25, nr);
+		ax25_calculate_rtt(ax25);
+		ax25_stop_t1timer(ax25);
+		ax25_start_t3timer(ax25);
+		return 1;
+	} else {
+		if (ax25->va != nr) {
+			ax25_frames_acked(ax25, nr);
+			ax25_calculate_t1(ax25);
+			ax25_start_t1timer(ax25);
+			return 1;
+		}
+	}
+	return 0;
+}
+