/*
* All outgoing AX.25 I frames pass via this routine. Therefore this is
* where the fragmentation of frames takes place.
*/
void ax25_output(ax25_cb *ax25, struct sk_buff *skb)
{
struct sk_buff *skbn;
unsigned char *p;
int frontlen, mtu, len, fragno, ka9qfrag, first = 1;
long flags;
/*
* dl1bke 960301: We use the new PACLEN parameter as MTU of the AX.25 layer.
* This will (hopefully) allow user programs to write() data
* w/o having to think of the maximal amount of data we can
* send with one call. It's called PACLEN to (1) avoid confusion
* with (IP) MTU and (2) TAPR calls this PACLEN, too ;-)
*/
mtu = ax25->paclen;
if ((skb->len - 1) > mtu) {
if (*skb->data == AX25_P_TEXT) {
skb_pull(skb, 1); /* skip PID */
ka9qfrag = 0;
} else {
mtu -= 2; /* Allow for fragment control info */
ka9qfrag = 1;
}
fragno = skb->len / mtu;
if (skb->len % mtu == 0) fragno--;
frontlen = skb_headroom(skb); /* Address space + CTRL */
while (skb->len > 0) {
save_flags(flags);
cli();
/*
* do _not_ use sock_alloc_send_skb, our socket may have
* sk->shutdown set...
*/
if ((skbn = alloc_skb(mtu + 2 + frontlen, GFP_ATOMIC)) == NULL) {
restore_flags(flags);
printk(KERN_DEBUG "ax25_output: alloc_skb returned NULL\n");
if (skb_device_locked(skb))
skb_device_unlock(skb);
return;
}
skbn->sk = skb->sk;
if (skbn->sk)
atomic_add(skbn->truesize, &skbn->sk->wmem_alloc);
restore_flags(flags);
skbn->free = 1;
skbn->arp = 1;
len = (mtu > skb->len) ? skb->len : mtu;
if (ka9qfrag == 1) {
skb_reserve(skbn, frontlen + 2);
memcpy(skb_put(skbn, len), skb->data, len);
p = skb_push(skbn, 2);
*p++ = AX25_P_SEGMENT;
*p = fragno--;
if (first) {
*p |= SEG_FIRST;
first = 0;
}
} else {
skb_reserve(skbn, frontlen + 1);
memcpy(skb_put(skbn, len), skb->data, 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 */
}
skb->free = 1;
kfree_skb(skb, FREE_WRITE);
} else {
skb_queue_tail(&ax25->write_queue, skb); /* Throw it on the queue */
}
if (ax25->state == AX25_STATE_3 || ax25->state == AX25_STATE_4) {
if (!ax25->dama_slave) /* bke 960114: we aren't allowed to transmit */
ax25_kick(ax25); /* in DAMA mode unless we received a Poll */
}
}
void dev_queue_xmit(struct sk_buff *skb, struct device *dev, int pri)
{
unsigned long flags;
int nitcount;
struct packet_type *ptype;
int where = 0; /* used to say if the packet should go */
/* at the front or the back of the */
/* queue - front is a retransmit try */
if (dev == NULL)
{
printk("dev.c: dev_queue_xmit: dev = NULL\n");
return;
}
if(pri>=0 && !skb_device_locked(skb))
skb_device_lock(skb); /* Shove a lock on the frame */
#ifdef CONFIG_SLAVE_BALANCING
save_flags(flags);
cli();
if(dev->slave!=NULL && dev->slave->pkt_queue < dev->pkt_queue &&
(dev->slave->flags & IFF_UP))
dev=dev->slave;
restore_flags(flags);
#endif
#ifdef CONFIG_SKB_CHECK
IS_SKB(skb);
#endif
skb->dev = dev;
/*
* This just eliminates some race conditions, but not all...
*/
if (skb->next != NULL)
{
/*
* Make sure we haven't missed an interrupt.
*/
printk("dev_queue_xmit: worked around a missed interrupt\n");
start_bh_atomic();
dev->hard_start_xmit(NULL, dev);
end_bh_atomic();
return;
}
/*
* Negative priority is used to flag a frame that is being pulled from the
* queue front as a retransmit attempt. It therefore goes back on the queue
* start on a failure.
*/
if (pri < 0)
{
pri = -pri-1;
where = 1;
}
if (pri >= DEV_NUMBUFFS)
{
printk("bad priority in dev_queue_xmit.\n");
pri = 1;
}
/*
* If the address has not been resolved. Call the device header rebuilder.
* This can cover all protocols and technically not just ARP either.
*/
if (!skb->arp && dev->rebuild_header(skb->data, dev, skb->raddr, skb)) {
return;
}
save_flags(flags);
cli();
if (!where) {
#ifdef CONFIG_SLAVE_BALANCING
skb->in_dev_queue=1;
#endif
skb_queue_tail(dev->buffs + pri,skb);
skb_device_unlock(skb); /* Buffer is on the device queue and can be freed safely */
skb = skb_dequeue(dev->buffs + pri);
skb_device_lock(skb); /* New buffer needs locking down */
#ifdef CONFIG_SLAVE_BALANCING
skb->in_dev_queue=0;
#endif
}
restore_flags(flags);
/* copy outgoing packets to any sniffer packet handlers */
if(!where)
{
for (nitcount= dev_nit, ptype = ptype_base; nitcount > 0 && ptype != NULL; ptype = ptype->next)
{
/* Never send packets back to the socket
* they originated from - MvS ([email protected])
*/
if (ptype->type == htons(ETH_P_ALL) &&
(ptype->dev == dev || !ptype->dev) &&
((struct sock *)ptype->data != skb->sk))
{
struct sk_buff *skb2;
if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL)
break;
/*
* The protocol knows this has (for other paths) been taken off
* and adds it back.
*/
skb2->len-=skb->dev->hard_header_len;
ptype->func(skb2, skb->dev, ptype);
nitcount--;
}
}
}
start_bh_atomic();
if (dev->hard_start_xmit(skb, dev) == 0) {
end_bh_atomic();
/*
* Packet is now solely the responsibility of the driver
*/
return;
}
end_bh_atomic();
/*
* Transmission failed, put skb back into a list. Once on the list it's safe and
* no longer device locked (it can be freed safely from the device queue)
*/
cli();
#ifdef CONFIG_SLAVE_BALANCING
skb->in_dev_queue=1;
dev->pkt_queue++;
#endif
skb_device_unlock(skb);
skb_queue_head(dev->buffs + pri,skb);
restore_flags(flags);
}
static void do_dev_queue_xmit(struct sk_buff *skb, struct device *dev, int pri)
{
unsigned long flags;
struct sk_buff_head *list;
int retransmission = 0; /* used to say if the packet should go */
/* at the front or the back of the */
/* queue - front is a retransmit try */
if(pri>=0 && !skb_device_locked(skb))
skb_device_lock(skb); /* Shove a lock on the frame */
#if CONFIG_SKB_CHECK
IS_SKB(skb);
#endif
skb->dev = dev;
/*
* Negative priority is used to flag a frame that is being pulled from the
* queue front as a retransmit attempt. It therefore goes back on the queue
* start on a failure.
*/
if (pri < 0)
{
pri = -pri-1;
retransmission = 1;
}
#ifdef CONFIG_NET_DEBUG
if (pri >= DEV_NUMBUFFS)
{
printk(KERN_WARNING "bad priority in dev_queue_xmit.\n");
pri = 1;
}
#endif
/*
* If the address has not been resolved. Call the device header rebuilder.
* This can cover all protocols and technically not just ARP either.
*/
if (!skb->arp && dev->rebuild_header(skb->data, dev, skb->raddr, skb)) {
return;
}
/*
*
* If dev is an alias, switch to its main device.
* "arp" resolution has been made with alias device, so
* arp entries refer to alias, not main.
*
*/
#ifdef CONFIG_NET_ALIAS
if (net_alias_is(dev))
skb->dev = dev = net_alias_dev_tx(dev);
#endif
/*
* If we are bridging and this is directly generated output
* pass the frame via the bridge.
*/
#ifdef CONFIG_BRIDGE
if(skb->pkt_bridged!=IS_BRIDGED && br_stats.flags & BR_UP)
{
if(br_tx_frame(skb))
return;
}
#endif
list = dev->buffs + pri;
save_flags(flags);
/* if this isn't a retransmission, use the first packet instead... */
if (!retransmission) {
if (skb_queue_len(list)) {
/* avoid overrunning the device queue.. */
if (skb_queue_len(list) > dev->tx_queue_len) {
dev_kfree_skb(skb, FREE_WRITE);
return;
}
}
/* copy outgoing packets to any sniffer packet handlers */
if (dev_nit) {
struct packet_type *ptype;
skb->stamp=xtime;
for (ptype = ptype_all; ptype!=NULL; ptype = ptype->next)
{
/* Never send packets back to the socket
* they originated from - MvS ([email protected])
*/
if ((ptype->dev == dev || !ptype->dev) &&
((struct sock *)ptype->data != skb->sk))
{
struct sk_buff *skb2;
if ((skb2 = skb_clone(skb, GFP_ATOMIC)) == NULL)
break;
/* FIXME?: Wrong when the hard_header_len
* is an upper bound. Is this even
* used anywhere?
*/
skb2->h.raw = skb2->data + dev->hard_header_len;
/* On soft header devices we
* yank the header before mac.raw
* back off. This is set by
* dev->hard_header().
*/
if (dev->flags&IFF_SOFTHEADERS)
skb_pull(skb2,skb2->mac.raw-skb2->data);
skb2->mac.raw = skb2->data;
ptype->func(skb2, skb->dev, ptype);
}
}
}
if (skb_queue_len(list)) {
cli();
skb_device_unlock(skb); /* Buffer is on the device queue and can be freed safely */
__skb_queue_tail(list, skb);
skb = __skb_dequeue(list);
skb_device_lock(skb); /* New buffer needs locking down */
restore_flags(flags);
}
}
if (dev->hard_start_xmit(skb, dev) == 0) {
/*
* Packet is now solely the responsibility of the driver
*/
return;
}
/*
* Transmission failed, put skb back into a list. Once on the list it's safe and
* no longer device locked (it can be freed safely from the device queue)
*/
cli();
skb_device_unlock(skb);
__skb_queue_head(list,skb);
restore_flags(flags);
}
