diff options
Diffstat (limited to 'net/ax25/ax25_ds_subr.c')
| -rw-r--r-- | net/ax25/ax25_ds_subr.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/net/ax25/ax25_ds_subr.c b/net/ax25/ax25_ds_subr.c new file mode 100644 index 000000000..f00e27df3 --- /dev/null +++ b/net/ax25/ax25_ds_subr.c @@ -0,0 +1,204 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * + * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk) + * Copyright (C) Joerg Reuter DL1BKE (jreuter@yaina.de) + */ +#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/spinlock.h> +#include <linux/net.h> +#include <linux/gfp.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> + +void ax25_ds_nr_error_recovery(ax25_cb *ax25) +{ + ax25_ds_establish_data_link(ax25); +} + +/* + * dl1bke 960114: transmit I frames on DAMA poll + */ +void ax25_ds_enquiry_response(ax25_cb *ax25) +{ + ax25_cb *ax25o; + + /* Please note that neither DK4EG's nor DG2FEF's + * DAMA spec mention the following behaviour as seen + * with TheFirmware: + * + * DB0ACH->DL1BKE <RR C P R0> [DAMA] + * DL1BKE->DB0ACH <I NR=0 NS=0> + * DL1BKE-7->DB0PRA-6 DB0ACH <I C S3 R5> + * DL1BKE->DB0ACH <RR R F R0> + * + * The Flexnet DAMA Master implementation apparently + * insists on the "proper" AX.25 behaviour: + * + * DB0ACH->DL1BKE <RR C P R0> [DAMA] + * DL1BKE->DB0ACH <RR R F R0> + * DL1BKE->DB0ACH <I NR=0 NS=0> + * DL1BKE-7->DB0PRA-6 DB0ACH <I C S3 R5> + * + * Flexnet refuses to send us *any* I frame if we send + * a REJ in case AX25_COND_REJECT is set. It is superfluous in + * this mode anyway (a RR or RNR invokes the retransmission). + * Is this a Flexnet bug? + */ + + ax25_std_enquiry_response(ax25); + + if (!(ax25->condition & AX25_COND_PEER_RX_BUSY)) { + ax25_requeue_frames(ax25); + ax25_kick(ax25); + } + + if (ax25->state == AX25_STATE_1 || ax25->state == AX25_STATE_2 || skb_peek(&ax25->ack_queue) != NULL) + ax25_ds_t1_timeout(ax25); + else + ax25->n2count = 0; + + ax25_start_t3timer(ax25); + ax25_ds_set_timer(ax25->ax25_dev); + + spin_lock(&ax25_list_lock); + ax25_for_each(ax25o, &ax25_list) { + if (ax25o == ax25) + continue; + + if (ax25o->ax25_dev != ax25->ax25_dev) + continue; + + if (ax25o->state == AX25_STATE_1 || ax25o->state == AX25_STATE_2) { + ax25_ds_t1_timeout(ax25o); + continue; + } + + if (!(ax25o->condition & AX25_COND_PEER_RX_BUSY) && ax25o->state == AX25_STATE_3) { + ax25_requeue_frames(ax25o); + ax25_kick(ax25o); + } + + if (ax25o->state == AX25_STATE_1 || ax25o->state == AX25_STATE_2 || skb_peek(&ax25o->ack_queue) != NULL) + ax25_ds_t1_timeout(ax25o); + + /* do not start T3 for listening sockets (tnx DD8NE) */ + + if (ax25o->state != AX25_STATE_0) + ax25_start_t3timer(ax25o); + } + spin_unlock(&ax25_list_lock); +} + +void ax25_ds_establish_data_link(ax25_cb *ax25) +{ + ax25->condition &= AX25_COND_DAMA_MODE; + ax25->n2count = 0; + ax25_calculate_t1(ax25); + ax25_start_t1timer(ax25); + ax25_stop_t2timer(ax25); + ax25_start_t3timer(ax25); +} + +/* + * :::FIXME::: + * This is a kludge. Not all drivers recognize kiss commands. + * We need a driver level request to switch duplex mode, that does + * either SCC changing, PI config or KISS as required. Currently + * this request isn't reliable. + */ +static void ax25_kiss_cmd(ax25_dev *ax25_dev, unsigned char cmd, unsigned char param) +{ + struct sk_buff *skb; + unsigned char *p; + + if (ax25_dev->dev == NULL) + return; + + if ((skb = alloc_skb(2, GFP_ATOMIC)) == NULL) + return; + + skb_reset_network_header(skb); + p = skb_put(skb, 2); + + *p++ = cmd; + *p++ = param; + + skb->protocol = ax25_type_trans(skb, ax25_dev->dev); + + dev_queue_xmit(skb); +} + +/* + * A nasty problem arises if we count the number of DAMA connections + * wrong, especially when connections on the device already existed + * and our network node (or the sysop) decides to turn on DAMA Master + * mode. We thus flag the 'real' slave connections with + * ax25->dama_slave=1 and look on every disconnect if still slave + * connections exist. + */ +static int ax25_check_dama_slave(ax25_dev *ax25_dev) +{ + ax25_cb *ax25; + int res = 0; + + spin_lock(&ax25_list_lock); + ax25_for_each(ax25, &ax25_list) + if (ax25->ax25_dev == ax25_dev && (ax25->condition & AX25_COND_DAMA_MODE) && ax25->state > AX25_STATE_1) { + res = 1; + break; + } + spin_unlock(&ax25_list_lock); + + return res; +} + +static void ax25_dev_dama_on(ax25_dev *ax25_dev) +{ + if (ax25_dev == NULL) + return; + + if (ax25_dev->dama.slave == 0) + ax25_kiss_cmd(ax25_dev, 5, 1); + + ax25_dev->dama.slave = 1; + ax25_ds_set_timer(ax25_dev); +} + +void ax25_dev_dama_off(ax25_dev *ax25_dev) +{ + if (ax25_dev == NULL) + return; + + if (ax25_dev->dama.slave && !ax25_check_dama_slave(ax25_dev)) { + ax25_kiss_cmd(ax25_dev, 5, 0); + ax25_dev->dama.slave = 0; + ax25_ds_del_timer(ax25_dev); + } +} + +void ax25_dama_on(ax25_cb *ax25) +{ + ax25_dev_dama_on(ax25->ax25_dev); + ax25->condition |= AX25_COND_DAMA_MODE; +} + +void ax25_dama_off(ax25_cb *ax25) +{ + ax25->condition &= ~AX25_COND_DAMA_MODE; + ax25_dev_dama_off(ax25->ax25_dev); +} |