forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
270 lines
5.7 KiB
270 lines
5.7 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
|
/* |
|
* |
|
* Copyright Jonathan Naylor G4KLX ([email protected]) |
|
* Copyright Darryl Miles G7LED ([email protected]) |
|
*/ |
|
#include <linux/errno.h> |
|
#include <linux/types.h> |
|
#include <linux/socket.h> |
|
#include <linux/in.h> |
|
#include <linux/kernel.h> |
|
#include <linux/timer.h> |
|
#include <linux/string.h> |
|
#include <linux/sockios.h> |
|
#include <linux/net.h> |
|
#include <linux/slab.h> |
|
#include <net/ax25.h> |
|
#include <linux/inet.h> |
|
#include <linux/netdevice.h> |
|
#include <linux/skbuff.h> |
|
#include <net/sock.h> |
|
#include <linux/uaccess.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; |
|
|
|
if (skb->len - NR_TRANSPORT_LEN > NR_MAX_PACKET_SIZE) { |
|
/* Save a copy of the Transport Header */ |
|
skb_copy_from_linear_data(skb, transport, 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 + NR_MAX_PACKET_SIZE, 0, &err)) == NULL) |
|
return; |
|
|
|
skb_reserve(skbn, frontlen); |
|
|
|
len = (NR_MAX_PACKET_SIZE > skb->len) ? skb->len : NR_MAX_PACKET_SIZE; |
|
|
|
/* Copy the user data */ |
|
skb_copy_from_linear_data(skb, skb_put(skbn, len), len); |
|
skb_pull(skb, len); |
|
|
|
/* Duplicate the Transport Header */ |
|
skb_push(skbn, NR_TRANSPORT_LEN); |
|
skb_copy_to_linear_data(skbn, transport, |
|
NR_TRANSPORT_LEN); |
|
if (skb->len > 0) |
|
skbn->data[4] |= NR_MORE_FLAG; |
|
|
|
skb_queue_tail(&sk->sk_write_queue, skbn); /* Throw it on the queue */ |
|
} |
|
|
|
kfree_skb(skb); |
|
} else { |
|
skb_queue_tail(&sk->sk_write_queue, skb); /* Throw it on the queue */ |
|
} |
|
|
|
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) |
|
{ |
|
struct nr_sock *nr = nr_sk(sk); |
|
|
|
if (skb == NULL) |
|
return; |
|
|
|
skb->data[2] = nr->vs; |
|
skb->data[3] = nr->vr; |
|
|
|
if (nr->condition & NR_COND_OWN_RX_BUSY) |
|
skb->data[4] |= NR_CHOKE_FLAG; |
|
|
|
nr_start_idletimer(sk); |
|
|
|
nr_transmit_buffer(sk, skb); |
|
} |
|
|
|
void nr_send_nak_frame(struct sock *sk) |
|
{ |
|
struct sk_buff *skb, *skbn; |
|
struct nr_sock *nr = nr_sk(sk); |
|
|
|
if ((skb = skb_peek(&nr->ack_queue)) == NULL) |
|
return; |
|
|
|
if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) |
|
return; |
|
|
|
skbn->data[2] = nr->va; |
|
skbn->data[3] = nr->vr; |
|
|
|
if (nr->condition & NR_COND_OWN_RX_BUSY) |
|
skbn->data[4] |= NR_CHOKE_FLAG; |
|
|
|
nr_transmit_buffer(sk, skbn); |
|
|
|
nr->condition &= ~NR_COND_ACK_PENDING; |
|
nr->vl = nr->vr; |
|
|
|
nr_stop_t1timer(sk); |
|
} |
|
|
|
void nr_kick(struct sock *sk) |
|
{ |
|
struct nr_sock *nr = nr_sk(sk); |
|
struct sk_buff *skb, *skbn; |
|
unsigned short start, end; |
|
|
|
if (nr->state != NR_STATE_3) |
|
return; |
|
|
|
if (nr->condition & NR_COND_PEER_RX_BUSY) |
|
return; |
|
|
|
if (!skb_peek(&sk->sk_write_queue)) |
|
return; |
|
|
|
start = (skb_peek(&nr->ack_queue) == NULL) ? nr->va : nr->vs; |
|
end = (nr->va + nr->window) % NR_MODULUS; |
|
|
|
if (start == end) |
|
return; |
|
|
|
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->sk_write_queue); |
|
|
|
do { |
|
if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) { |
|
skb_queue_head(&sk->sk_write_queue, skb); |
|
break; |
|
} |
|
|
|
skb_set_owner_w(skbn, sk); |
|
|
|
/* |
|
* Transmit the frame copy. |
|
*/ |
|
nr_send_iframe(sk, skbn); |
|
|
|
nr->vs = (nr->vs + 1) % NR_MODULUS; |
|
|
|
/* |
|
* Requeue the original data frame. |
|
*/ |
|
skb_queue_tail(&nr->ack_queue, skb); |
|
|
|
} while (nr->vs != end && |
|
(skb = skb_dequeue(&sk->sk_write_queue)) != NULL); |
|
|
|
nr->vl = nr->vr; |
|
nr->condition &= ~NR_COND_ACK_PENDING; |
|
|
|
if (!nr_t1timer_running(sk)) |
|
nr_start_t1timer(sk); |
|
} |
|
|
|
void nr_transmit_buffer(struct sock *sk, struct sk_buff *skb) |
|
{ |
|
struct nr_sock *nr = nr_sk(sk); |
|
unsigned char *dptr; |
|
|
|
/* |
|
* Add the protocol byte and network header. |
|
*/ |
|
dptr = skb_push(skb, NR_NETWORK_LEN); |
|
|
|
memcpy(dptr, &nr->source_addr, AX25_ADDR_LEN); |
|
dptr[6] &= ~AX25_CBIT; |
|
dptr[6] &= ~AX25_EBIT; |
|
dptr[6] |= AX25_SSSID_SPARE; |
|
dptr += AX25_ADDR_LEN; |
|
|
|
memcpy(dptr, &nr->dest_addr, AX25_ADDR_LEN); |
|
dptr[6] &= ~AX25_CBIT; |
|
dptr[6] |= AX25_EBIT; |
|
dptr[6] |= AX25_SSSID_SPARE; |
|
dptr += AX25_ADDR_LEN; |
|
|
|
*dptr++ = sysctl_netrom_network_ttl_initialiser; |
|
|
|
if (!nr_route_frame(skb, NULL)) { |
|
kfree_skb(skb); |
|
nr_disconnect(sk, ENETUNREACH); |
|
} |
|
} |
|
|
|
/* |
|
* 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) |
|
{ |
|
struct nr_sock *nr = nr_sk(sk); |
|
|
|
nr->condition = 0x00; |
|
nr->n2count = 0; |
|
|
|
nr_write_internal(sk, NR_CONNREQ); |
|
|
|
nr_stop_t2timer(sk); |
|
nr_stop_t4timer(sk); |
|
nr_stop_idletimer(sk); |
|
nr_start_t1timer(sk); |
|
} |
|
|
|
/* |
|
* Never send a NAK when we are CHOKEd. |
|
*/ |
|
void nr_enquiry_response(struct sock *sk) |
|
{ |
|
struct nr_sock *nr = nr_sk(sk); |
|
int frametype = NR_INFOACK; |
|
|
|
if (nr->condition & NR_COND_OWN_RX_BUSY) { |
|
frametype |= NR_CHOKE_FLAG; |
|
} else { |
|
if (skb_peek(&nr->reseq_queue) != NULL) |
|
frametype |= NR_NAK_FLAG; |
|
} |
|
|
|
nr_write_internal(sk, frametype); |
|
|
|
nr->vl = nr->vr; |
|
nr->condition &= ~NR_COND_ACK_PENDING; |
|
} |
|
|
|
void nr_check_iframes_acked(struct sock *sk, unsigned short nr) |
|
{ |
|
struct nr_sock *nrom = nr_sk(sk); |
|
|
|
if (nrom->vs == nr) { |
|
nr_frames_acked(sk, nr); |
|
nr_stop_t1timer(sk); |
|
nrom->n2count = 0; |
|
} else { |
|
if (nrom->va != nr) { |
|
nr_frames_acked(sk, nr); |
|
nr_start_t1timer(sk); |
|
} |
|
} |
|
}
|
|
|