/*
* NET/ROM release 003
*
* This is ALPHA test software. This code may break your machine, randomly fail to work with new
* releases, misbehave and/or generally screw up. It might even work.
*
* This code REQUIRES 1.2.1 or higher/ NET3.029
*
* This module:
* This module 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.
*
* History
* NET/ROM 001 Jonathan(G4KLX) Cloned from ax25_out.c
* NET/ROM 003 Jonathan(G4KLX) Added NET/ROM fragmentation.
* Darryl(G7LED) Fixed NAK, to give out correct reponse.
*/
#include <linux/config.h>
#ifdef CONFIG_NETROM
#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/net.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <asm/segment.h>
#include <asm/system.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, mtu;
mtu = sk->nr->paclen;
if (skb->len - NR_TRANSPORT_LEN > mtu) {
/* Save a copy of the Transport Header */
memcpy(transport, skb->data, 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 + mtu, 0, 0, &err)) == NULL)
return;
skbn->sk = sk;
skbn->free = 1;
skbn->arp = 1;
skb_reserve(skbn, frontlen);
len = (mtu > skb->len) ? skb->len : mtu;
/* Copy the user data */
memcpy(skb_put(skbn, len), skb->data, len);
skb_pull(skb, len);
/* Duplicate the Transport Header */
skb_push(skbn, NR_TRANSPORT_LEN);
memcpy(skbn->data, transport, NR_TRANSPORT_LEN);
if (skb->len > 0)
skbn->data[4] |= NR_MORE_FLAG;
skb_queue_tail(&sk->write_queue, skbn); /* Throw it on the queue */
}
skb->free = 1;
kfree_skb(skb, FREE_WRITE);
} else {
skb_queue_tail(&sk->write_queue, skb); /* Throw it on the queue */
}
if (sk->nr->state == NR_STATE_3)
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)
{
if (skb == NULL)
return;
skb->data[2] = sk->nr->vs;
skb->data[3] = sk->nr->vr;
if (sk->nr->condition & OWN_RX_BUSY_CONDITION)
skb->data[4] |= NR_CHOKE_FLAG;
nr_transmit_buffer(sk, skb);
}
void nr_send_nak_frame(struct sock *sk)
{
struct sk_buff *skb, *skbn;
if ((skb = skb_peek(&sk->nr->ack_queue)) == NULL)
return;
if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL)
return;
skbn->data[2] = sk->nr->va;
skbn->data[3] = sk->nr->vr;
if (sk->nr->condition & OWN_RX_BUSY_CONDITION)
skbn->data[4] |= NR_CHOKE_FLAG;
nr_transmit_buffer(sk, skbn);
sk->nr->condition &= ~ACK_PENDING_CONDITION;
sk->nr->vl = sk->nr->vr;
sk->nr->t1timer = 0;
}
void nr_kick(struct sock *sk)
{
struct sk_buff *skb, *skbn;
int last = 1;
unsigned short start, end, next;
del_timer(&sk->timer);
start = (skb_peek(&sk->nr->ack_queue) == NULL) ? sk->nr->va : sk->nr->vs;
end = (sk->nr->va + sk->window) % NR_MODULUS;
if (!(sk->nr->condition & PEER_RX_BUSY_CONDITION) &&
start != end &&
skb_peek(&sk->write_queue) != NULL) {
sk->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->write_queue);
do {
if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
skb_queue_head(&sk->write_queue, skb);
break;
}
next = (sk->nr->vs + 1) % NR_MODULUS;
last = (next == end);
/*
* Transmit the frame copy.
*/
nr_send_iframe(sk, skbn);
sk->nr->vs = next;
/*
* Requeue the original data frame.
*/
skb_queue_tail(&sk->nr->ack_queue, skb);
} while (!last && (skb = skb_dequeue(&sk->write_queue)) != NULL);
sk->nr->vl = sk->nr->vr;
sk->nr->condition &= ~ACK_PENDING_CONDITION;
if (sk->nr->t1timer == 0) {
sk->nr->t1timer = sk->nr->t1 = nr_calculate_t1(sk);
}
}
nr_set_timer(sk);
}
void nr_transmit_buffer(struct sock *sk, struct sk_buff *skb)
{
unsigned char *dptr;
/*
* Add the protocol byte and network header.
*/
dptr = skb_push(skb, NR_NETWORK_LEN);
memcpy(dptr, &sk->nr->source_addr, AX25_ADDR_LEN);
dptr[6] &= ~LAPB_C;
dptr[6] &= ~LAPB_E;
dptr[6] |= SSSID_SPARE;
dptr += AX25_ADDR_LEN;
memcpy(dptr, &sk->nr->dest_addr, AX25_ADDR_LEN);
dptr[6] &= ~LAPB_C;
dptr[6] |= LAPB_E;
dptr[6] |= SSSID_SPARE;
dptr += AX25_ADDR_LEN;
*dptr++ = nr_default.ttl;
skb->arp = 1;
if (!nr_route_frame(skb, NULL)) {
kfree_skb(skb, FREE_WRITE);
sk->state = TCP_CLOSE;
sk->err = ENETUNREACH;
if (!sk->dead)
sk->state_change(sk);
sk->dead = 1;
}
}
/*
* 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)
{
sk->nr->condition = 0x00;
sk->nr->n2count = 0;
nr_write_internal(sk, NR_CONNREQ);
sk->nr->t2timer = 0;
sk->nr->t1timer = sk->nr->t1 = nr_calculate_t1(sk);
}
/*
* Never send a NAK when we are CHOKEd.
*/
void nr_enquiry_response(struct sock *sk)
{
int frametype = NR_INFOACK;
if (sk->nr->condition & OWN_RX_BUSY_CONDITION) {
frametype |= NR_CHOKE_FLAG;
} else {
if (skb_peek(&sk->nr->reseq_queue) != NULL) {
frametype |= NR_NAK_FLAG;
}
}
nr_write_internal(sk, frametype);
sk->nr->vl = sk->nr->vr;
sk->nr->condition &= ~ACK_PENDING_CONDITION;
}
void nr_check_iframes_acked(struct sock *sk, unsigned short nr)
{
if (sk->nr->vs == nr) {
nr_frames_acked(sk, nr);
nr_calculate_rtt(sk);
sk->nr->t1timer = 0;
sk->nr->n2count = 0;
} else {
if (sk->nr->va != nr) {
nr_frames_acked(sk, nr);
sk->nr->t1timer = sk->nr->t1 = nr_calculate_t1(sk);
}
}
}
#endif
