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/*
* NET/ROM release 007
*
* This code REQUIRES 2.1.15 or higher/ NET3.038
*
* 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.
*
* Most of this code is based on the SDL diagrams published in the 7th
* ARRL Computer Networking Conference papers. The diagrams have mistakes
* in them, but are mostly correct. Before you modify the code could you
* read the SDL diagrams as the code is not obvious and probably very
* easy to break;
*
* History
* NET/ROM 001 Jonathan(G4KLX) Cloned from ax25_in.c
* NET/ROM 003 Jonathan(G4KLX) Added NET/ROM fragment reception.
* Darryl(G7LED) Added missing INFO with NAK case, optimized
* INFOACK handling, removed reconnect on error.
* NET/ROM 006 Jonathan(G4KLX) Hdrincl removal changes.
* NET/ROM 007 Jonathan(G4KLX) New timer architecture.
*/
#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 <net/ip.h> /* For ip_rcv */
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <net/netrom.h>
static int nr_queue_rx_frame(struct sock *sk, struct sk_buff *skb, int more)
{
struct sk_buff *skbo, *skbn = skb;
skb_pull(skb, NR_NETWORK_LEN + NR_TRANSPORT_LEN);
nr_start_idletimer(sk);
if (more) {
sk->protinfo.nr->fraglen += skb->len;
skb_queue_tail(&sk->protinfo.nr->frag_queue, skb);
return 0;
}
if (!more && sk->protinfo.nr->fraglen > 0) { /* End of fragment */
sk->protinfo.nr->fraglen += skb->len;
skb_queue_tail(&sk->protinfo.nr->frag_queue, skb);
if ((skbn = alloc_skb(sk->protinfo.nr->fraglen, GFP_ATOMIC)) == NULL)
return 1;
skbn->h.raw = skbn->data;
while ((skbo = skb_dequeue(&sk->protinfo.nr->frag_queue)) != NULL) {
memcpy(skb_put(skbn, skbo->len), skbo->data, skbo->len);
kfree_skb(skbo);
}
sk->protinfo.nr->fraglen = 0;
}
return sock_queue_rcv_skb(sk, skbn);
}
/*
* State machine for state 1, Awaiting Connection State.
* The handling of the timer(s) is in file nr_timer.c.
* Handling of state 0 and connection release is in netrom.c.
*/
static int nr_state1_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
switch (frametype) {
case NR_CONNACK:
nr_stop_t1timer(sk);
nr_start_idletimer(sk);
sk->protinfo.nr->your_index = skb->data[17];
sk->protinfo.nr->your_id = skb->data[18];
sk->protinfo.nr->vs = 0;
sk->protinfo.nr->va = 0;
sk->protinfo.nr->vr = 0;
sk->protinfo.nr->vl = 0;
sk->protinfo.nr->state = NR_STATE_3;
sk->protinfo.nr->n2count = 0;
sk->protinfo.nr->window = skb->data[20];
sk->state = TCP_ESTABLISHED;
if (!sk->dead)
sk->state_change(sk);
break;
case NR_CONNACK | NR_CHOKE_FLAG:
nr_disconnect(sk, ECONNREFUSED);
break;
default:
break;
}
return 0;
}
/*
* State machine for state 2, Awaiting Release State.
* The handling of the timer(s) is in file nr_timer.c
* Handling of state 0 and connection release is in netrom.c.
*/
static int nr_state2_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
switch (frametype) {
case NR_CONNACK | NR_CHOKE_FLAG:
nr_disconnect(sk, ECONNRESET);
break;
case NR_DISCREQ:
nr_write_internal(sk, NR_DISCACK);
case NR_DISCACK:
nr_disconnect(sk, 0);
break;
default:
break;
}
return 0;
}
/*
* State machine for state 3, Connected State.
* The handling of the timer(s) is in file nr_timer.c
* Handling of state 0 and connection release is in netrom.c.
*/
static int nr_state3_machine(struct sock *sk, struct sk_buff *skb, int frametype)
{
struct sk_buff_head temp_queue;
struct sk_buff *skbn;
unsigned short save_vr;
unsigned short nr, ns;
int queued = 0;
nr = skb->data[18];
ns = skb->data[17];
switch (frametype) {
case NR_CONNREQ:
nr_write_internal(sk, NR_CONNACK);
break;
case NR_DISCREQ:
nr_write_internal(sk, NR_DISCACK);
nr_disconnect(sk, 0);
break;
case NR_CONNACK | NR_CHOKE_FLAG:
case NR_DISCACK:
nr_disconnect(sk, ECONNRESET);
break;
case NR_INFOACK:
case NR_INFOACK | NR_CHOKE_FLAG:
case NR_INFOACK | NR_NAK_FLAG:
case NR_INFOACK | NR_NAK_FLAG | NR_CHOKE_FLAG:
if (frametype & NR_CHOKE_FLAG) {
sk->protinfo.nr->condition |= NR_COND_PEER_RX_BUSY;
nr_start_t4timer(sk);
} else {
sk->protinfo.nr->condition &= ~NR_COND_PEER_RX_BUSY;
nr_stop_t4timer(sk);
}
if (!nr_validate_nr(sk, nr)) {
break;
}
if (frametype & NR_NAK_FLAG) {
nr_frames_acked(sk, nr);
nr_send_nak_frame(sk);
} else {
if (sk->protinfo.nr->condition & NR_COND_PEER_RX_BUSY) {
nr_frames_acked(sk, nr);
} else {
nr_check_iframes_acked(sk, nr);
}
}
break;
case NR_INFO:
case NR_INFO | NR_NAK_FLAG:
case NR_INFO | NR_CHOKE_FLAG:
case NR_INFO | NR_MORE_FLAG:
case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG:
case NR_INFO | NR_CHOKE_FLAG | NR_MORE_FLAG:
case NR_INFO | NR_NAK_FLAG | NR_MORE_FLAG:
case NR_INFO | NR_NAK_FLAG | NR_CHOKE_FLAG | NR_MORE_FLAG:
if (frametype & NR_CHOKE_FLAG) {
sk->protinfo.nr->condition |= NR_COND_PEER_RX_BUSY;
nr_start_t4timer(sk);
} else {
sk->protinfo.nr->condition &= ~NR_COND_PEER_RX_BUSY;
nr_stop_t4timer(sk);
}
if (nr_validate_nr(sk, nr)) {
if (frametype & NR_NAK_FLAG) {
nr_frames_acked(sk, nr);
nr_send_nak_frame(sk);
} else {
if (sk->protinfo.nr->condition & NR_COND_PEER_RX_BUSY) {
nr_frames_acked(sk, nr);
} else {
nr_check_iframes_acked(sk, nr);
}
}
}
queued = 1;
skb_queue_head(&sk->protinfo.nr->reseq_queue, skb);
if (sk->protinfo.nr->condition & NR_COND_OWN_RX_BUSY)
break;
skb_queue_head_init(&temp_queue);
do {
save_vr = sk->protinfo.nr->vr;
while ((skbn = skb_dequeue(&sk->protinfo.nr->reseq_queue)) != NULL) {
ns = skbn->data[17];
if (ns == sk->protinfo.nr->vr) {
if (nr_queue_rx_frame(sk, skbn, frametype & NR_MORE_FLAG) == 0) {
sk->protinfo.nr->vr = (sk->protinfo.nr->vr + 1) % NR_MODULUS;
} else {
sk->protinfo.nr->condition |= NR_COND_OWN_RX_BUSY;
skb_queue_tail(&temp_queue, skbn);
}
} else if (nr_in_rx_window(sk, ns)) {
skb_queue_tail(&temp_queue, skbn);
} else {
kfree_skb(skbn);
}
}
while ((skbn = skb_dequeue(&temp_queue)) != NULL) {
skb_queue_tail(&sk->protinfo.nr->reseq_queue, skbn);
}
} while (save_vr != sk->protinfo.nr->vr);
/*
* Window is full, ack it immediately.
*/
if (((sk->protinfo.nr->vl + sk->protinfo.nr->window) % NR_MODULUS) == sk->protinfo.nr->vr) {
nr_enquiry_response(sk);
} else {
if (!(sk->protinfo.nr->condition & NR_COND_ACK_PENDING)) {
sk->protinfo.nr->condition |= NR_COND_ACK_PENDING;
nr_start_t2timer(sk);
}
}
break;
default:
break;
}
return queued;
}
/* Higher level upcall for a LAPB frame */
int nr_process_rx_frame(struct sock *sk, struct sk_buff *skb)
{
int queued = 0, frametype;
if (sk->protinfo.nr->state == NR_STATE_0)
return 0;
frametype = skb->data[19];
switch (sk->protinfo.nr->state) {
case NR_STATE_1:
queued = nr_state1_machine(sk, skb, frametype);
break;
case NR_STATE_2:
queued = nr_state2_machine(sk, skb, frametype);
break;
case NR_STATE_3:
queued = nr_state3_machine(sk, skb, frametype);
break;
}
nr_kick(sk);
return queued;
}
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