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linux-next/net/netrom/nr_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

271 lines
5.7 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
*
* Copyright Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
* Copyright Darryl Miles G7LED (dlm@g7led.demon.co.uk)
*/
#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 <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>
#include <net/netrom.h>
/*
* This is where all NET/ROM frames pass, except for IP-over-NET/ROM which
* cannot be fragmented in this manner.
*/
void nr_output(struct sock *sk, struct sk_buff *skb)
{
struct sk_buff *skbn;
unsigned char transport[NR_TRANSPORT_LEN];
int err, frontlen, len;
if (skb->len - NR_TRANSPORT_LEN > NR_MAX_PACKET_SIZE) {
/* Save a copy of the Transport Header */
skb_copy_from_linear_data(skb, transport, NR_TRANSPORT_LEN);
skb_pull(skb, NR_TRANSPORT_LEN);
frontlen = skb_headroom(skb);
while (skb->len > 0) {
if ((skbn = sock_alloc_send_skb(sk, frontlen + NR_MAX_PACKET_SIZE, 0, &err)) == NULL)
return;
skb_reserve(skbn, frontlen);
len = (NR_MAX_PACKET_SIZE > skb->len) ? skb->len : NR_MAX_PACKET_SIZE;
/* Copy the user data */
skb_copy_from_linear_data(skb, skb_put(skbn, len), len);
skb_pull(skb, len);
/* Duplicate the Transport Header */
skb_push(skbn, NR_TRANSPORT_LEN);
skb_copy_to_linear_data(skbn, transport,
NR_TRANSPORT_LEN);
if (skb->len > 0)
skbn->data[4] |= NR_MORE_FLAG;
skb_queue_tail(&sk->sk_write_queue, skbn); /* Throw it on the queue */
}
kfree_skb(skb);
} else {
skb_queue_tail(&sk->sk_write_queue, skb); /* Throw it on the queue */
}
nr_kick(sk);
}
/*
* 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 nr_send_iframe(struct sock *sk, struct sk_buff *skb)
{
struct nr_sock *nr = nr_sk(sk);
if (skb == NULL)
return;
skb->data[2] = nr->vs;
skb->data[3] = nr->vr;
if (nr->condition & NR_COND_OWN_RX_BUSY)
skb->data[4] |= NR_CHOKE_FLAG;
nr_start_idletimer(sk);
nr_transmit_buffer(sk, skb);
}
void nr_send_nak_frame(struct sock *sk)
{
struct sk_buff *skb, *skbn;
struct nr_sock *nr = nr_sk(sk);
if ((skb = skb_peek(&nr->ack_queue)) == NULL)
return;
if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL)
return;
skbn->data[2] = nr->va;
skbn->data[3] = nr->vr;
if (nr->condition & NR_COND_OWN_RX_BUSY)
skbn->data[4] |= NR_CHOKE_FLAG;
nr_transmit_buffer(sk, skbn);
nr->condition &= ~NR_COND_ACK_PENDING;
nr->vl = nr->vr;
nr_stop_t1timer(sk);
}
void nr_kick(struct sock *sk)
{
struct nr_sock *nr = nr_sk(sk);
struct sk_buff *skb, *skbn;
unsigned short start, end;
if (nr->state != NR_STATE_3)
return;
if (nr->condition & NR_COND_PEER_RX_BUSY)
return;
if (!skb_peek(&sk->sk_write_queue))
return;
start = (skb_peek(&nr->ack_queue) == NULL) ? nr->va : nr->vs;
end = (nr->va + nr->window) % NR_MODULUS;
if (start == end)
return;
nr->vs = start;
/*
* Transmit data until either we're out of data to send or
* the window is full.
*/
/*
* Dequeue the frame and copy it.
*/
skb = skb_dequeue(&sk->sk_write_queue);
do {
if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
skb_queue_head(&sk->sk_write_queue, skb);
break;
}
skb_set_owner_w(skbn, sk);
/*
* Transmit the frame copy.
*/
nr_send_iframe(sk, skbn);
nr->vs = (nr->vs + 1) % NR_MODULUS;
/*
* Requeue the original data frame.
*/
skb_queue_tail(&nr->ack_queue, skb);
} while (nr->vs != end &&
(skb = skb_dequeue(&sk->sk_write_queue)) != NULL);
nr->vl = nr->vr;
nr->condition &= ~NR_COND_ACK_PENDING;
if (!nr_t1timer_running(sk))
nr_start_t1timer(sk);
}
void nr_transmit_buffer(struct sock *sk, struct sk_buff *skb)
{
struct nr_sock *nr = nr_sk(sk);
unsigned char *dptr;
/*
* Add the protocol byte and network header.
*/
dptr = skb_push(skb, NR_NETWORK_LEN);
memcpy(dptr, &nr->source_addr, AX25_ADDR_LEN);
dptr[6] &= ~AX25_CBIT;
dptr[6] &= ~AX25_EBIT;
dptr[6] |= AX25_SSSID_SPARE;
dptr += AX25_ADDR_LEN;
memcpy(dptr, &nr->dest_addr, AX25_ADDR_LEN);
dptr[6] &= ~AX25_CBIT;
dptr[6] |= AX25_EBIT;
dptr[6] |= AX25_SSSID_SPARE;
dptr += AX25_ADDR_LEN;
*dptr++ = sysctl_netrom_network_ttl_initialiser;
if (!nr_route_frame(skb, NULL)) {
kfree_skb(skb);
nr_disconnect(sk, ENETUNREACH);
}
}
/*
* The following routines are taken from page 170 of the 7th ARRL Computer
* Networking Conference paper, as is the whole state machine.
*/
void nr_establish_data_link(struct sock *sk)
{
struct nr_sock *nr = nr_sk(sk);
nr->condition = 0x00;
nr->n2count = 0;
nr_write_internal(sk, NR_CONNREQ);
nr_stop_t2timer(sk);
nr_stop_t4timer(sk);
nr_stop_idletimer(sk);
nr_start_t1timer(sk);
}
/*
* Never send a NAK when we are CHOKEd.
*/
void nr_enquiry_response(struct sock *sk)
{
struct nr_sock *nr = nr_sk(sk);
int frametype = NR_INFOACK;
if (nr->condition & NR_COND_OWN_RX_BUSY) {
frametype |= NR_CHOKE_FLAG;
} else {
if (skb_peek(&nr->reseq_queue) != NULL)
frametype |= NR_NAK_FLAG;
}
nr_write_internal(sk, frametype);
nr->vl = nr->vr;
nr->condition &= ~NR_COND_ACK_PENDING;
}
void nr_check_iframes_acked(struct sock *sk, unsigned short nr)
{
struct nr_sock *nrom = nr_sk(sk);
if (nrom->vs == nr) {
nr_frames_acked(sk, nr);
nr_stop_t1timer(sk);
nrom->n2count = 0;
} else {
if (nrom->va != nr) {
nr_frames_acked(sk, nr);
nr_start_t1timer(sk);
}
}
}