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-rw-r--r--net/ax25/ax25_out.c386
1 files changed, 386 insertions, 0 deletions
diff --git a/net/ax25/ax25_out.c b/net/ax25/ax25_out.c
new file mode 100644
index 000000000..3db76d247
--- /dev/null
+++ b/net/ax25/ax25_out.c
@@ -0,0 +1,386 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ * 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/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/spinlock.h>
+#include <linux/net.h>
+#include <linux/slab.h>
+#include <net/ax25.h>
+#include <linux/inet.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <net/sock.h>
+#include <linux/uaccess.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, const 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) {
+ ax25->digipeat = kmemdup(digi, sizeof(*digi), GFP_ATOMIC);
+ if (ax25->digipeat == NULL) {
+ ax25_cb_put(ax25);
+ return NULL;
+ }
+ }
+
+ 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
+ }
+
+ /*
+ * There is one ref for the state machine; a caller needs
+ * one more to put it back, just like with the existing one.
+ */
+ ax25_cb_hold(ax25);
+
+ 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 */
+}
+
+EXPORT_SYMBOL(ax25_send_frame);
+
+/*
+ * 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 (paclen < 16) {
+ WARN_ON_ONCE(1);
+ kfree_skb(skb);
+ return;
+ }
+
+ 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);
+ skb_set_network_header(skbn,
+ skb_network_offset(skb));
+ skb_copy_from_linear_data(skb, skb_put(skbn, len), 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);
+ skb_set_network_header(skbn,
+ skb_network_offset(skb));
+ skb_copy_from_linear_data(skb, skb_put(skbn, len), 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_reset_network_header(skb);
+
+ 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;
+
+ /*
+ * 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.
+ * Check for race with ax25_clear_queues().
+ */
+ skb = skb_dequeue(&ax25->write_queue);
+ if (!skb)
+ return;
+
+ ax25->vs = start;
+
+ 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)
+{
+ unsigned char *ptr;
+ int headroom;
+
+ if (ax25->ax25_dev == NULL) {
+ ax25_disconnect(ax25, ENETUNREACH);
+ return;
+ }
+
+ headroom = ax25_addr_size(ax25->digipeat);
+
+ if (unlikely(skb_headroom(skb) < headroom)) {
+ skb = skb_expand_head(skb, headroom);
+ if (!skb) {
+ printk(KERN_CRIT "AX.25: ax25_transmit_buffer - out of memory\n");
+ return;
+ }
+ }
+
+ ptr = skb_push(skb, headroom);
+
+ ax25_addr_build(ptr, &ax25->source_addr, &ax25->dest_addr, ax25->digipeat, type, ax25->modulus);
+
+ ax25_queue_xmit(skb, ax25->ax25_dev->dev);
+}
+
+/*
+ * 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, struct net_device *dev)
+{
+ unsigned char *ptr;
+
+ skb->protocol = ax25_type_trans(skb, ax25_fwd_dev(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;
+}
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