linux/net/ax25/ax25_out.c
Thomas Gleixner 2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00

394 lines
8.6 KiB
C

// 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, 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)
{
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);
consume_skb(skb);
skb = skbn;
}
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;
}