399 lines
8.9 KiB
C
399 lines
8.9 KiB
C
/*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk)
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* Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
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* Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de)
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*/
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#include <linux/errno.h>
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#include <linux/types.h>
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#include <linux/socket.h>
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#include <linux/in.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/timer.h>
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#include <linux/string.h>
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#include <linux/sockios.h>
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#include <linux/spinlock.h>
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#include <linux/net.h>
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#include <linux/slab.h>
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#include <net/ax25.h>
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#include <linux/inet.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <linux/netfilter.h>
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#include <net/sock.h>
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#include <asm/uaccess.h>
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#include <linux/fcntl.h>
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#include <linux/mm.h>
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#include <linux/interrupt.h>
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static DEFINE_SPINLOCK(ax25_frag_lock);
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ax25_cb *ax25_send_frame(struct sk_buff *skb, int paclen, ax25_address *src, ax25_address *dest, ax25_digi *digi, struct net_device *dev)
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{
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ax25_dev *ax25_dev;
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ax25_cb *ax25;
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/*
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* Take the default packet length for the device if zero is
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* specified.
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*/
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if (paclen == 0) {
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if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
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return NULL;
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paclen = ax25_dev->values[AX25_VALUES_PACLEN];
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}
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/*
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* Look for an existing connection.
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*/
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if ((ax25 = ax25_find_cb(src, dest, digi, dev)) != NULL) {
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ax25_output(ax25, paclen, skb);
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return ax25; /* It already existed */
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}
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if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
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return NULL;
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if ((ax25 = ax25_create_cb()) == NULL)
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return NULL;
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ax25_fillin_cb(ax25, ax25_dev);
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ax25->source_addr = *src;
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ax25->dest_addr = *dest;
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if (digi != NULL) {
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ax25->digipeat = kmemdup(digi, sizeof(*digi), GFP_ATOMIC);
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if (ax25->digipeat == NULL) {
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ax25_cb_put(ax25);
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return NULL;
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}
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}
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switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
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case AX25_PROTO_STD_SIMPLEX:
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case AX25_PROTO_STD_DUPLEX:
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ax25_std_establish_data_link(ax25);
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break;
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#ifdef CONFIG_AX25_DAMA_SLAVE
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case AX25_PROTO_DAMA_SLAVE:
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if (ax25_dev->dama.slave)
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ax25_ds_establish_data_link(ax25);
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else
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ax25_std_establish_data_link(ax25);
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break;
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#endif
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}
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/*
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* There is one ref for the state machine; a caller needs
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* one more to put it back, just like with the existing one.
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*/
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ax25_cb_hold(ax25);
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ax25_cb_add(ax25);
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ax25->state = AX25_STATE_1;
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ax25_start_heartbeat(ax25);
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ax25_output(ax25, paclen, skb);
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return ax25; /* We had to create it */
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}
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EXPORT_SYMBOL(ax25_send_frame);
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/*
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* All outgoing AX.25 I frames pass via this routine. Therefore this is
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* where the fragmentation of frames takes place. If fragment is set to
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* zero then we are not allowed to do fragmentation, even if the frame
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* is too large.
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*/
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void ax25_output(ax25_cb *ax25, int paclen, struct sk_buff *skb)
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{
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struct sk_buff *skbn;
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unsigned char *p;
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int frontlen, len, fragno, ka9qfrag, first = 1;
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if (paclen < 16) {
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WARN_ON_ONCE(1);
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kfree_skb(skb);
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return;
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}
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if ((skb->len - 1) > paclen) {
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if (*skb->data == AX25_P_TEXT) {
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skb_pull(skb, 1); /* skip PID */
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ka9qfrag = 0;
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} else {
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paclen -= 2; /* Allow for fragment control info */
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ka9qfrag = 1;
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}
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fragno = skb->len / paclen;
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if (skb->len % paclen == 0) fragno--;
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frontlen = skb_headroom(skb); /* Address space + CTRL */
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while (skb->len > 0) {
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spin_lock_bh(&ax25_frag_lock);
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if ((skbn = alloc_skb(paclen + 2 + frontlen, GFP_ATOMIC)) == NULL) {
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spin_unlock_bh(&ax25_frag_lock);
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printk(KERN_CRIT "AX.25: ax25_output - out of memory\n");
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return;
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}
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if (skb->sk != NULL)
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skb_set_owner_w(skbn, skb->sk);
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spin_unlock_bh(&ax25_frag_lock);
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len = (paclen > skb->len) ? skb->len : paclen;
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if (ka9qfrag == 1) {
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skb_reserve(skbn, frontlen + 2);
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skb_set_network_header(skbn,
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skb_network_offset(skb));
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skb_copy_from_linear_data(skb, skb_put(skbn, len), len);
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p = skb_push(skbn, 2);
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*p++ = AX25_P_SEGMENT;
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*p = fragno--;
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if (first) {
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*p |= AX25_SEG_FIRST;
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first = 0;
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}
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} else {
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skb_reserve(skbn, frontlen + 1);
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skb_set_network_header(skbn,
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skb_network_offset(skb));
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skb_copy_from_linear_data(skb, skb_put(skbn, len), len);
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p = skb_push(skbn, 1);
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*p = AX25_P_TEXT;
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}
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skb_pull(skb, len);
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skb_queue_tail(&ax25->write_queue, skbn); /* Throw it on the queue */
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}
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kfree_skb(skb);
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} else {
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skb_queue_tail(&ax25->write_queue, skb); /* Throw it on the queue */
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}
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switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
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case AX25_PROTO_STD_SIMPLEX:
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case AX25_PROTO_STD_DUPLEX:
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ax25_kick(ax25);
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break;
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#ifdef CONFIG_AX25_DAMA_SLAVE
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/*
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* A DAMA slave is _required_ to work as normal AX.25L2V2
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* if no DAMA master is available.
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*/
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case AX25_PROTO_DAMA_SLAVE:
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if (!ax25->ax25_dev->dama.slave) ax25_kick(ax25);
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break;
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#endif
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}
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}
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/*
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* This procedure is passed a buffer descriptor for an iframe. It builds
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* the rest of the control part of the frame and then writes it out.
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*/
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static void ax25_send_iframe(ax25_cb *ax25, struct sk_buff *skb, int poll_bit)
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{
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unsigned char *frame;
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if (skb == NULL)
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return;
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skb_reset_network_header(skb);
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if (ax25->modulus == AX25_MODULUS) {
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frame = skb_push(skb, 1);
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*frame = AX25_I;
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*frame |= (poll_bit) ? AX25_PF : 0;
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*frame |= (ax25->vr << 5);
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*frame |= (ax25->vs << 1);
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} else {
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frame = skb_push(skb, 2);
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frame[0] = AX25_I;
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frame[0] |= (ax25->vs << 1);
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frame[1] = (poll_bit) ? AX25_EPF : 0;
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frame[1] |= (ax25->vr << 1);
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}
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ax25_start_idletimer(ax25);
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ax25_transmit_buffer(ax25, skb, AX25_COMMAND);
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}
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void ax25_kick(ax25_cb *ax25)
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{
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struct sk_buff *skb, *skbn;
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int last = 1;
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unsigned short start, end, next;
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if (ax25->state != AX25_STATE_3 && ax25->state != AX25_STATE_4)
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return;
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if (ax25->condition & AX25_COND_PEER_RX_BUSY)
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return;
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if (skb_peek(&ax25->write_queue) == NULL)
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return;
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start = (skb_peek(&ax25->ack_queue) == NULL) ? ax25->va : ax25->vs;
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end = (ax25->va + ax25->window) % ax25->modulus;
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if (start == end)
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return;
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/*
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* Transmit data until either we're out of data to send or
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* the window is full. Send a poll on the final I frame if
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* the window is filled.
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*/
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/*
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* Dequeue the frame and copy it.
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* Check for race with ax25_clear_queues().
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*/
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skb = skb_dequeue(&ax25->write_queue);
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if (!skb)
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return;
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ax25->vs = start;
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do {
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if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
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skb_queue_head(&ax25->write_queue, skb);
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break;
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}
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if (skb->sk != NULL)
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skb_set_owner_w(skbn, skb->sk);
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next = (ax25->vs + 1) % ax25->modulus;
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last = (next == end);
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/*
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* Transmit the frame copy.
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* bke 960114: do not set the Poll bit on the last frame
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* in DAMA mode.
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*/
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switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) {
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case AX25_PROTO_STD_SIMPLEX:
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case AX25_PROTO_STD_DUPLEX:
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ax25_send_iframe(ax25, skbn, (last) ? AX25_POLLON : AX25_POLLOFF);
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break;
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#ifdef CONFIG_AX25_DAMA_SLAVE
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case AX25_PROTO_DAMA_SLAVE:
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ax25_send_iframe(ax25, skbn, AX25_POLLOFF);
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break;
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#endif
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}
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ax25->vs = next;
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/*
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* Requeue the original data frame.
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*/
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skb_queue_tail(&ax25->ack_queue, skb);
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} while (!last && (skb = skb_dequeue(&ax25->write_queue)) != NULL);
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ax25->condition &= ~AX25_COND_ACK_PENDING;
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if (!ax25_t1timer_running(ax25)) {
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ax25_stop_t3timer(ax25);
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ax25_calculate_t1(ax25);
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ax25_start_t1timer(ax25);
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}
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}
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void ax25_transmit_buffer(ax25_cb *ax25, struct sk_buff *skb, int type)
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{
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struct sk_buff *skbn;
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unsigned char *ptr;
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int headroom;
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if (ax25->ax25_dev == NULL) {
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ax25_disconnect(ax25, ENETUNREACH);
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return;
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}
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headroom = ax25_addr_size(ax25->digipeat);
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if (skb_headroom(skb) < headroom) {
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if ((skbn = skb_realloc_headroom(skb, headroom)) == NULL) {
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printk(KERN_CRIT "AX.25: ax25_transmit_buffer - out of memory\n");
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kfree_skb(skb);
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return;
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}
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if (skb->sk != NULL)
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skb_set_owner_w(skbn, skb->sk);
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kfree_skb(skb);
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skb = skbn;
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}
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ptr = skb_push(skb, headroom);
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ax25_addr_build(ptr, &ax25->source_addr, &ax25->dest_addr, ax25->digipeat, type, ax25->modulus);
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ax25_queue_xmit(skb, ax25->ax25_dev->dev);
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}
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/*
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* A small shim to dev_queue_xmit to add the KISS control byte, and do
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* any packet forwarding in operation.
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*/
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void ax25_queue_xmit(struct sk_buff *skb, struct net_device *dev)
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{
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unsigned char *ptr;
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skb->protocol = ax25_type_trans(skb, ax25_fwd_dev(dev));
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ptr = skb_push(skb, 1);
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*ptr = 0x00; /* KISS */
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dev_queue_xmit(skb);
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}
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int ax25_check_iframes_acked(ax25_cb *ax25, unsigned short nr)
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{
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if (ax25->vs == nr) {
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ax25_frames_acked(ax25, nr);
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ax25_calculate_rtt(ax25);
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ax25_stop_t1timer(ax25);
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ax25_start_t3timer(ax25);
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return 1;
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} else {
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if (ax25->va != nr) {
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ax25_frames_acked(ax25, nr);
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ax25_calculate_t1(ax25);
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ax25_start_t1timer(ax25);
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return 1;
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}
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}
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return 0;
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}
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