/*
* small macro to drop non-digipeated digipeaters and reverse path
*/
static inline void ax25_route_invert(ax25_digi *in, ax25_digi *out)
{
int k;
for (k = 0; k < in->ndigi; k++)
if (!in->repeated[k])
break;
in->ndigi = k;
ax25_digi_invert(in, out);
}
static int ax25_rcv(struct sk_buff *skb, struct net_device *dev,
ax25_address *dev_addr, struct packet_type *ptype)
{
ax25_address src, dest, *next_digi = NULL;
int type = 0, mine = 0, dama;
struct sock *make, *sk;
ax25_digi dp, reverse_dp;
ax25_cb *ax25;
ax25_dev *ax25_dev;
/*
* Process the AX.25/LAPB frame.
*/
skb_reset_transport_header(skb);
if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) {
kfree_skb(skb);
return 0;
}
/*
* Parse the address header.
*/
if (ax25_addr_parse(skb->data, skb->len, &src, &dest, &dp, &type, &dama) == NULL) {
kfree_skb(skb);
return 0;
}
/*
* Ours perhaps ?
*/
if (dp.lastrepeat + 1 < dp.ndigi) /* Not yet digipeated completely */
next_digi = &dp.calls[dp.lastrepeat + 1];
/*
* Pull of the AX.25 headers leaving the CTRL/PID bytes
*/
skb_pull(skb, ax25_addr_size(&dp));
/* For our port addresses ? */
if (ax25cmp(&dest, dev_addr) == 0 && dp.lastrepeat + 1 == dp.ndigi)
mine = 1;
/* Also match on any registered callsign from L3/4 */
if (!mine && ax25_listen_mine(&dest, dev) && dp.lastrepeat + 1 == dp.ndigi)
mine = 1;
/* UI frame - bypass LAPB processing */
if ((*skb->data & ~0x10) == AX25_UI && dp.lastrepeat + 1 == dp.ndigi) {
skb_set_transport_header(skb, 2); /* skip control and pid */
ax25_send_to_raw(&dest, skb, skb->data[1]);
if (!mine && ax25cmp(&dest, (ax25_address *)dev->broadcast) != 0) {
kfree_skb(skb);
return 0;
}
/* Now we are pointing at the pid byte */
switch (skb->data[1]) {
case AX25_P_IP:
skb_pull(skb,2); /* drop PID/CTRL */
skb_reset_transport_header(skb);
skb_reset_network_header(skb);
skb->dev = dev;
skb->pkt_type = PACKET_HOST;
skb->protocol = htons(ETH_P_IP);
netif_rx(skb);
break;
case AX25_P_ARP:
skb_pull(skb,2);
skb_reset_transport_header(skb);
skb_reset_network_header(skb);
skb->dev = dev;
skb->pkt_type = PACKET_HOST;
skb->protocol = htons(ETH_P_ARP);
netif_rx(skb);
break;
case AX25_P_TEXT:
/* Now find a suitable dgram socket */
sk = ax25_get_socket(&dest, &src, SOCK_DGRAM);
if (sk != NULL) {
bh_lock_sock(sk);
if (atomic_read(&sk->sk_rmem_alloc) >=
sk->sk_rcvbuf) {
kfree_skb(skb);
} else {
/*
* Remove the control and PID.
*/
skb_pull(skb, 2);
if (sock_queue_rcv_skb(sk, skb) != 0)
kfree_skb(skb);
}
bh_unlock_sock(sk);
sock_put(sk);
} else {
kfree_skb(skb);
}
break;
default:
kfree_skb(skb); /* Will scan SOCK_AX25 RAW sockets */
break;
}
return 0;
}
/*
* Is connected mode supported on this device ?
* If not, should we DM the incoming frame (except DMs) or
* silently ignore them. For now we stay quiet.
*/
if (ax25_dev->values[AX25_VALUES_CONMODE] == 0) {
kfree_skb(skb);
return 0;
}
/* LAPB */
/* AX.25 state 1-4 */
ax25_digi_invert(&dp, &reverse_dp);
if ((ax25 = ax25_find_cb(&dest, &src, &reverse_dp, dev)) != NULL) {
/*
* Process the frame. If it is queued up internally it
* returns one otherwise we free it immediately. This
* routine itself wakes the user context layers so we do
* no further work
*/
if (ax25_process_rx_frame(ax25, skb, type, dama) == 0)
kfree_skb(skb);
ax25_cb_put(ax25);
return 0;
}
/* AX.25 state 0 (disconnected) */
/* a) received not a SABM(E) */
if ((*skb->data & ~AX25_PF) != AX25_SABM &&
(*skb->data & ~AX25_PF) != AX25_SABME) {
/*
* Never reply to a DM. Also ignore any connects for
* addresses that are not our interfaces and not a socket.
*/
if ((*skb->data & ~AX25_PF) != AX25_DM && mine)
ax25_return_dm(dev, &src, &dest, &dp);
kfree_skb(skb);
return 0;
}
/* b) received SABM(E) */
if (dp.lastrepeat + 1 == dp.ndigi)
sk = ax25_find_listener(&dest, 0, dev, SOCK_SEQPACKET);
else
sk = ax25_find_listener(next_digi, 1, dev, SOCK_SEQPACKET);
if (sk != NULL) {
bh_lock_sock(sk);
if (sk_acceptq_is_full(sk) ||
(make = ax25_make_new(sk, ax25_dev)) == NULL) {
if (mine)
ax25_return_dm(dev, &src, &dest, &dp);
kfree_skb(skb);
bh_unlock_sock(sk);
sock_put(sk);
return 0;
}
ax25 = ax25_sk(make);
skb_set_owner_r(skb, make);
skb_queue_head(&sk->sk_receive_queue, skb);
make->sk_state = TCP_ESTABLISHED;
sk->sk_ack_backlog++;
bh_unlock_sock(sk);
} else {
if (!mine) {
kfree_skb(skb);
return 0;
}
if ((ax25 = ax25_create_cb()) == NULL) {
ax25_return_dm(dev, &src, &dest, &dp);
kfree_skb(skb);
return 0;
}
ax25_fillin_cb(ax25, ax25_dev);
}
ax25->source_addr = dest;
ax25->dest_addr = src;
/*
* Sort out any digipeated paths.
*/
if (dp.ndigi && !ax25->digipeat &&
(ax25->digipeat = kmalloc(sizeof(ax25_digi), GFP_ATOMIC)) == NULL) {
kfree_skb(skb);
ax25_destroy_socket(ax25);
if (sk)
sock_put(sk);
return 0;
}
if (dp.ndigi == 0) {
kfree(ax25->digipeat);
ax25->digipeat = NULL;
} else {
/* Reverse the source SABM's path */
memcpy(ax25->digipeat, &reverse_dp, sizeof(ax25_digi));
}
if ((*skb->data & ~AX25_PF) == AX25_SABME) {
ax25->modulus = AX25_EMODULUS;
ax25->window = ax25_dev->values[AX25_VALUES_EWINDOW];
} else {
ax25->modulus = AX25_MODULUS;
ax25->window = ax25_dev->values[AX25_VALUES_WINDOW];
}
ax25_send_control(ax25, AX25_UA, AX25_POLLON, AX25_RESPONSE);
#ifdef CONFIG_AX25_DAMA_SLAVE
if (dama && ax25->ax25_dev->values[AX25_VALUES_PROTOCOL] == AX25_PROTO_DAMA_SLAVE)
ax25_dama_on(ax25);
#endif
ax25->state = AX25_STATE_3;
ax25_cb_add(ax25);
ax25_start_heartbeat(ax25);
ax25_start_t3timer(ax25);
ax25_start_idletimer(ax25);
if (sk) {
if (!sock_flag(sk, SOCK_DEAD))
sk->sk_data_ready(sk, skb->len);
sock_put(sk);
} else
kfree_skb(skb);
return 0;
}