diff options
Diffstat (limited to 'net/lapb')
| -rw-r--r-- | net/lapb/Kconfig | 22 | ||||
| -rw-r--r-- | net/lapb/Makefile | 8 | ||||
| -rw-r--r-- | net/lapb/lapb_iface.c | 436 | ||||
| -rw-r--r-- | net/lapb/lapb_in.c | 556 | ||||
| -rw-r--r-- | net/lapb/lapb_out.c | 205 | ||||
| -rw-r--r-- | net/lapb/lapb_subr.c | 299 | ||||
| -rw-r--r-- | net/lapb/lapb_timer.c | 172 |
7 files changed, 1698 insertions, 0 deletions
diff --git a/net/lapb/Kconfig b/net/lapb/Kconfig new file mode 100644 index 000000000..da87b47f0 --- /dev/null +++ b/net/lapb/Kconfig @@ -0,0 +1,22 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# LAPB Data Link Drive +# + +config LAPB + tristate "LAPB Data Link Driver" + help + Link Access Procedure, Balanced (LAPB) is the data link layer (i.e. + the lower) part of the X.25 protocol. It offers a reliable + connection service to exchange data frames with one other host, and + it is used to transport higher level protocols (mostly X.25 Packet + Layer, the higher part of X.25, but others are possible as well). + Usually, LAPB is used with specialized X.21 network cards, but Linux + currently supports LAPB only over Ethernet connections. If you want + to use LAPB connections over Ethernet, say Y here and to "LAPB over + Ethernet driver" below. Read + <file:Documentation/networking/lapb-module.rst> for technical + details. + + To compile this driver as a module, choose M here: the + module will be called lapb. If unsure, say N. diff --git a/net/lapb/Makefile b/net/lapb/Makefile new file mode 100644 index 000000000..7be91b4c0 --- /dev/null +++ b/net/lapb/Makefile @@ -0,0 +1,8 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Makefile for the Linux LAPB layer. +# + +obj-$(CONFIG_LAPB) += lapb.o + +lapb-y := lapb_in.o lapb_out.o lapb_subr.o lapb_timer.o lapb_iface.o diff --git a/net/lapb/lapb_iface.c b/net/lapb/lapb_iface.c new file mode 100644 index 000000000..3c03f6512 --- /dev/null +++ b/net/lapb/lapb_iface.c @@ -0,0 +1,436 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * LAPB release 002 + * + * This code REQUIRES 2.1.15 or higher/ NET3.038 + * + * History + * LAPB 001 Jonathan Naylor Started Coding + * LAPB 002 Jonathan Naylor New timer architecture. + * 2000-10-29 Henner Eisen lapb_data_indication() return status. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/module.h> +#include <linux/errno.h> +#include <linux/types.h> +#include <linux/socket.h> +#include <linux/in.h> +#include <linux/kernel.h> +#include <linux/jiffies.h> +#include <linux/timer.h> +#include <linux/string.h> +#include <linux/sockios.h> +#include <linux/net.h> +#include <linux/inet.h> +#include <linux/if_arp.h> +#include <linux/skbuff.h> +#include <linux/slab.h> +#include <net/sock.h> +#include <linux/uaccess.h> +#include <linux/fcntl.h> +#include <linux/mm.h> +#include <linux/interrupt.h> +#include <linux/stat.h> +#include <linux/init.h> +#include <net/lapb.h> + +static LIST_HEAD(lapb_list); +static DEFINE_RWLOCK(lapb_list_lock); + +/* + * Free an allocated lapb control block. + */ +static void lapb_free_cb(struct lapb_cb *lapb) +{ + kfree(lapb); +} + +static __inline__ void lapb_hold(struct lapb_cb *lapb) +{ + refcount_inc(&lapb->refcnt); +} + +static __inline__ void lapb_put(struct lapb_cb *lapb) +{ + if (refcount_dec_and_test(&lapb->refcnt)) + lapb_free_cb(lapb); +} + +/* + * Socket removal during an interrupt is now safe. + */ +static void __lapb_remove_cb(struct lapb_cb *lapb) +{ + if (lapb->node.next) { + list_del(&lapb->node); + lapb_put(lapb); + } +} + +/* + * Add a socket to the bound sockets list. + */ +static void __lapb_insert_cb(struct lapb_cb *lapb) +{ + list_add(&lapb->node, &lapb_list); + lapb_hold(lapb); +} + +static struct lapb_cb *__lapb_devtostruct(struct net_device *dev) +{ + struct list_head *entry; + struct lapb_cb *lapb, *use = NULL; + + list_for_each(entry, &lapb_list) { + lapb = list_entry(entry, struct lapb_cb, node); + if (lapb->dev == dev) { + use = lapb; + break; + } + } + + if (use) + lapb_hold(use); + + return use; +} + +static struct lapb_cb *lapb_devtostruct(struct net_device *dev) +{ + struct lapb_cb *rc; + + read_lock_bh(&lapb_list_lock); + rc = __lapb_devtostruct(dev); + read_unlock_bh(&lapb_list_lock); + + return rc; +} +/* + * Create an empty LAPB control block. + */ +static struct lapb_cb *lapb_create_cb(void) +{ + struct lapb_cb *lapb = kzalloc(sizeof(*lapb), GFP_ATOMIC); + + if (!lapb) + goto out; + + skb_queue_head_init(&lapb->write_queue); + skb_queue_head_init(&lapb->ack_queue); + + timer_setup(&lapb->t1timer, NULL, 0); + timer_setup(&lapb->t2timer, NULL, 0); + + lapb->t1 = LAPB_DEFAULT_T1; + lapb->t2 = LAPB_DEFAULT_T2; + lapb->n2 = LAPB_DEFAULT_N2; + lapb->mode = LAPB_DEFAULT_MODE; + lapb->window = LAPB_DEFAULT_WINDOW; + lapb->state = LAPB_STATE_0; + refcount_set(&lapb->refcnt, 1); +out: + return lapb; +} + +int lapb_register(struct net_device *dev, + const struct lapb_register_struct *callbacks) +{ + struct lapb_cb *lapb; + int rc = LAPB_BADTOKEN; + + write_lock_bh(&lapb_list_lock); + + lapb = __lapb_devtostruct(dev); + if (lapb) { + lapb_put(lapb); + goto out; + } + + lapb = lapb_create_cb(); + rc = LAPB_NOMEM; + if (!lapb) + goto out; + + lapb->dev = dev; + lapb->callbacks = callbacks; + + __lapb_insert_cb(lapb); + + lapb_start_t1timer(lapb); + + rc = LAPB_OK; +out: + write_unlock_bh(&lapb_list_lock); + return rc; +} +EXPORT_SYMBOL(lapb_register); + +int lapb_unregister(struct net_device *dev) +{ + struct lapb_cb *lapb; + int rc = LAPB_BADTOKEN; + + write_lock_bh(&lapb_list_lock); + lapb = __lapb_devtostruct(dev); + if (!lapb) + goto out; + lapb_put(lapb); + + lapb_stop_t1timer(lapb); + lapb_stop_t2timer(lapb); + + lapb_clear_queues(lapb); + + __lapb_remove_cb(lapb); + + lapb_put(lapb); + rc = LAPB_OK; +out: + write_unlock_bh(&lapb_list_lock); + return rc; +} +EXPORT_SYMBOL(lapb_unregister); + +int lapb_getparms(struct net_device *dev, struct lapb_parms_struct *parms) +{ + int rc = LAPB_BADTOKEN; + struct lapb_cb *lapb = lapb_devtostruct(dev); + + if (!lapb) + goto out; + + parms->t1 = lapb->t1 / HZ; + parms->t2 = lapb->t2 / HZ; + parms->n2 = lapb->n2; + parms->n2count = lapb->n2count; + parms->state = lapb->state; + parms->window = lapb->window; + parms->mode = lapb->mode; + + if (!timer_pending(&lapb->t1timer)) + parms->t1timer = 0; + else + parms->t1timer = (lapb->t1timer.expires - jiffies) / HZ; + + if (!timer_pending(&lapb->t2timer)) + parms->t2timer = 0; + else + parms->t2timer = (lapb->t2timer.expires - jiffies) / HZ; + + lapb_put(lapb); + rc = LAPB_OK; +out: + return rc; +} +EXPORT_SYMBOL(lapb_getparms); + +int lapb_setparms(struct net_device *dev, struct lapb_parms_struct *parms) +{ + int rc = LAPB_BADTOKEN; + struct lapb_cb *lapb = lapb_devtostruct(dev); + + if (!lapb) + goto out; + + rc = LAPB_INVALUE; + if (parms->t1 < 1 || parms->t2 < 1 || parms->n2 < 1) + goto out_put; + + if (lapb->state == LAPB_STATE_0) { + if (parms->mode & LAPB_EXTENDED) { + if (parms->window < 1 || parms->window > 127) + goto out_put; + } else { + if (parms->window < 1 || parms->window > 7) + goto out_put; + } + lapb->mode = parms->mode; + lapb->window = parms->window; + } + + lapb->t1 = parms->t1 * HZ; + lapb->t2 = parms->t2 * HZ; + lapb->n2 = parms->n2; + + rc = LAPB_OK; +out_put: + lapb_put(lapb); +out: + return rc; +} +EXPORT_SYMBOL(lapb_setparms); + +int lapb_connect_request(struct net_device *dev) +{ + struct lapb_cb *lapb = lapb_devtostruct(dev); + int rc = LAPB_BADTOKEN; + + if (!lapb) + goto out; + + rc = LAPB_OK; + if (lapb->state == LAPB_STATE_1) + goto out_put; + + rc = LAPB_CONNECTED; + if (lapb->state == LAPB_STATE_3 || lapb->state == LAPB_STATE_4) + goto out_put; + + lapb_establish_data_link(lapb); + + lapb_dbg(0, "(%p) S0 -> S1\n", lapb->dev); + lapb->state = LAPB_STATE_1; + + rc = LAPB_OK; +out_put: + lapb_put(lapb); +out: + return rc; +} +EXPORT_SYMBOL(lapb_connect_request); + +int lapb_disconnect_request(struct net_device *dev) +{ + struct lapb_cb *lapb = lapb_devtostruct(dev); + int rc = LAPB_BADTOKEN; + + if (!lapb) + goto out; + + switch (lapb->state) { + case LAPB_STATE_0: + rc = LAPB_NOTCONNECTED; + goto out_put; + + case LAPB_STATE_1: + lapb_dbg(1, "(%p) S1 TX DISC(1)\n", lapb->dev); + lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev); + lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND); + lapb->state = LAPB_STATE_0; + lapb_start_t1timer(lapb); + rc = LAPB_NOTCONNECTED; + goto out_put; + + case LAPB_STATE_2: + rc = LAPB_OK; + goto out_put; + } + + lapb_clear_queues(lapb); + lapb->n2count = 0; + lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND); + lapb_start_t1timer(lapb); + lapb_stop_t2timer(lapb); + lapb->state = LAPB_STATE_2; + + lapb_dbg(1, "(%p) S3 DISC(1)\n", lapb->dev); + lapb_dbg(0, "(%p) S3 -> S2\n", lapb->dev); + + rc = LAPB_OK; +out_put: + lapb_put(lapb); +out: + return rc; +} +EXPORT_SYMBOL(lapb_disconnect_request); + +int lapb_data_request(struct net_device *dev, struct sk_buff *skb) +{ + struct lapb_cb *lapb = lapb_devtostruct(dev); + int rc = LAPB_BADTOKEN; + + if (!lapb) + goto out; + + rc = LAPB_NOTCONNECTED; + if (lapb->state != LAPB_STATE_3 && lapb->state != LAPB_STATE_4) + goto out_put; + + skb_queue_tail(&lapb->write_queue, skb); + lapb_kick(lapb); + rc = LAPB_OK; +out_put: + lapb_put(lapb); +out: + return rc; +} +EXPORT_SYMBOL(lapb_data_request); + +int lapb_data_received(struct net_device *dev, struct sk_buff *skb) +{ + struct lapb_cb *lapb = lapb_devtostruct(dev); + int rc = LAPB_BADTOKEN; + + if (lapb) { + lapb_data_input(lapb, skb); + lapb_put(lapb); + rc = LAPB_OK; + } + + return rc; +} +EXPORT_SYMBOL(lapb_data_received); + +void lapb_connect_confirmation(struct lapb_cb *lapb, int reason) +{ + if (lapb->callbacks->connect_confirmation) + lapb->callbacks->connect_confirmation(lapb->dev, reason); +} + +void lapb_connect_indication(struct lapb_cb *lapb, int reason) +{ + if (lapb->callbacks->connect_indication) + lapb->callbacks->connect_indication(lapb->dev, reason); +} + +void lapb_disconnect_confirmation(struct lapb_cb *lapb, int reason) +{ + if (lapb->callbacks->disconnect_confirmation) + lapb->callbacks->disconnect_confirmation(lapb->dev, reason); +} + +void lapb_disconnect_indication(struct lapb_cb *lapb, int reason) +{ + if (lapb->callbacks->disconnect_indication) + lapb->callbacks->disconnect_indication(lapb->dev, reason); +} + +int lapb_data_indication(struct lapb_cb *lapb, struct sk_buff *skb) +{ + if (lapb->callbacks->data_indication) + return lapb->callbacks->data_indication(lapb->dev, skb); + + kfree_skb(skb); + return NET_RX_SUCCESS; /* For now; must be != NET_RX_DROP */ +} + +int lapb_data_transmit(struct lapb_cb *lapb, struct sk_buff *skb) +{ + int used = 0; + + if (lapb->callbacks->data_transmit) { + lapb->callbacks->data_transmit(lapb->dev, skb); + used = 1; + } + + return used; +} + +static int __init lapb_init(void) +{ + return 0; +} + +static void __exit lapb_exit(void) +{ + WARN_ON(!list_empty(&lapb_list)); +} + +MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>"); +MODULE_DESCRIPTION("The X.25 Link Access Procedure B link layer protocol"); +MODULE_LICENSE("GPL"); + +module_init(lapb_init); +module_exit(lapb_exit); diff --git a/net/lapb/lapb_in.c b/net/lapb/lapb_in.c new file mode 100644 index 000000000..38ae23c09 --- /dev/null +++ b/net/lapb/lapb_in.c @@ -0,0 +1,556 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * LAPB release 002 + * + * This code REQUIRES 2.1.15 or higher/ NET3.038 + * + * History + * LAPB 001 Jonathan Naulor Started Coding + * LAPB 002 Jonathan Naylor New timer architecture. + * 2000-10-29 Henner Eisen lapb_data_indication() return status. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#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/inet.h> +#include <linux/netdevice.h> +#include <linux/skbuff.h> +#include <linux/slab.h> +#include <net/sock.h> +#include <linux/uaccess.h> +#include <linux/fcntl.h> +#include <linux/mm.h> +#include <linux/interrupt.h> +#include <net/lapb.h> + +/* + * State machine for state 0, Disconnected State. + * The handling of the timer(s) is in file lapb_timer.c. + */ +static void lapb_state0_machine(struct lapb_cb *lapb, struct sk_buff *skb, + struct lapb_frame *frame) +{ + switch (frame->type) { + case LAPB_SABM: + lapb_dbg(1, "(%p) S0 RX SABM(%d)\n", lapb->dev, frame->pf); + if (lapb->mode & LAPB_EXTENDED) { + lapb_dbg(1, "(%p) S0 TX DM(%d)\n", + lapb->dev, frame->pf); + lapb_send_control(lapb, LAPB_DM, frame->pf, + LAPB_RESPONSE); + } else { + lapb_dbg(1, "(%p) S0 TX UA(%d)\n", + lapb->dev, frame->pf); + lapb_dbg(0, "(%p) S0 -> S3\n", lapb->dev); + lapb_send_control(lapb, LAPB_UA, frame->pf, + LAPB_RESPONSE); + lapb_stop_t1timer(lapb); + lapb_stop_t2timer(lapb); + lapb->state = LAPB_STATE_3; + lapb->condition = 0x00; + lapb->n2count = 0; + lapb->vs = 0; + lapb->vr = 0; + lapb->va = 0; + lapb_connect_indication(lapb, LAPB_OK); + } + break; + + case LAPB_SABME: + lapb_dbg(1, "(%p) S0 RX SABME(%d)\n", lapb->dev, frame->pf); + if (lapb->mode & LAPB_EXTENDED) { + lapb_dbg(1, "(%p) S0 TX UA(%d)\n", + lapb->dev, frame->pf); + lapb_dbg(0, "(%p) S0 -> S3\n", lapb->dev); + lapb_send_control(lapb, LAPB_UA, frame->pf, + LAPB_RESPONSE); + lapb_stop_t1timer(lapb); + lapb_stop_t2timer(lapb); + lapb->state = LAPB_STATE_3; + lapb->condition = 0x00; + lapb->n2count = 0; + lapb->vs = 0; + lapb->vr = 0; + lapb->va = 0; + lapb_connect_indication(lapb, LAPB_OK); + } else { + lapb_dbg(1, "(%p) S0 TX DM(%d)\n", + lapb->dev, frame->pf); + lapb_send_control(lapb, LAPB_DM, frame->pf, + LAPB_RESPONSE); + } + break; + + case LAPB_DISC: + lapb_dbg(1, "(%p) S0 RX DISC(%d)\n", lapb->dev, frame->pf); + lapb_dbg(1, "(%p) S0 TX UA(%d)\n", lapb->dev, frame->pf); + lapb_send_control(lapb, LAPB_UA, frame->pf, LAPB_RESPONSE); + break; + + default: + break; + } + + kfree_skb(skb); +} + +/* + * State machine for state 1, Awaiting Connection State. + * The handling of the timer(s) is in file lapb_timer.c. + */ +static void lapb_state1_machine(struct lapb_cb *lapb, struct sk_buff *skb, + struct lapb_frame *frame) +{ + switch (frame->type) { + case LAPB_SABM: + lapb_dbg(1, "(%p) S1 RX SABM(%d)\n", lapb->dev, frame->pf); + if (lapb->mode & LAPB_EXTENDED) { + lapb_dbg(1, "(%p) S1 TX DM(%d)\n", + lapb->dev, frame->pf); + lapb_send_control(lapb, LAPB_DM, frame->pf, + LAPB_RESPONSE); + } else { + lapb_dbg(1, "(%p) S1 TX UA(%d)\n", + lapb->dev, frame->pf); + lapb_send_control(lapb, LAPB_UA, frame->pf, + LAPB_RESPONSE); + } + break; + + case LAPB_SABME: + lapb_dbg(1, "(%p) S1 RX SABME(%d)\n", lapb->dev, frame->pf); + if (lapb->mode & LAPB_EXTENDED) { + lapb_dbg(1, "(%p) S1 TX UA(%d)\n", + lapb->dev, frame->pf); + lapb_send_control(lapb, LAPB_UA, frame->pf, + LAPB_RESPONSE); + } else { + lapb_dbg(1, "(%p) S1 TX DM(%d)\n", + lapb->dev, frame->pf); + lapb_send_control(lapb, LAPB_DM, frame->pf, + LAPB_RESPONSE); + } + break; + + case LAPB_DISC: + lapb_dbg(1, "(%p) S1 RX DISC(%d)\n", lapb->dev, frame->pf); + lapb_dbg(1, "(%p) S1 TX DM(%d)\n", lapb->dev, frame->pf); + lapb_send_control(lapb, LAPB_DM, frame->pf, LAPB_RESPONSE); + break; + + case LAPB_UA: + lapb_dbg(1, "(%p) S1 RX UA(%d)\n", lapb->dev, frame->pf); + if (frame->pf) { + lapb_dbg(0, "(%p) S1 -> S3\n", lapb->dev); + lapb_stop_t1timer(lapb); + lapb_stop_t2timer(lapb); + lapb->state = LAPB_STATE_3; + lapb->condition = 0x00; + lapb->n2count = 0; + lapb->vs = 0; + lapb->vr = 0; + lapb->va = 0; + lapb_connect_confirmation(lapb, LAPB_OK); + } + break; + + case LAPB_DM: + lapb_dbg(1, "(%p) S1 RX DM(%d)\n", lapb->dev, frame->pf); + if (frame->pf) { + lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev); + lapb_clear_queues(lapb); + lapb->state = LAPB_STATE_0; + lapb_start_t1timer(lapb); + lapb_stop_t2timer(lapb); + lapb_disconnect_indication(lapb, LAPB_REFUSED); + } + break; + } + + kfree_skb(skb); +} + +/* + * State machine for state 2, Awaiting Release State. + * The handling of the timer(s) is in file lapb_timer.c + */ +static void lapb_state2_machine(struct lapb_cb *lapb, struct sk_buff *skb, + struct lapb_frame *frame) +{ + switch (frame->type) { + case LAPB_SABM: + case LAPB_SABME: + lapb_dbg(1, "(%p) S2 RX {SABM,SABME}(%d)\n", + lapb->dev, frame->pf); + lapb_dbg(1, "(%p) S2 TX DM(%d)\n", lapb->dev, frame->pf); + lapb_send_control(lapb, LAPB_DM, frame->pf, LAPB_RESPONSE); + break; + + case LAPB_DISC: + lapb_dbg(1, "(%p) S2 RX DISC(%d)\n", lapb->dev, frame->pf); + lapb_dbg(1, "(%p) S2 TX UA(%d)\n", lapb->dev, frame->pf); + lapb_send_control(lapb, LAPB_UA, frame->pf, LAPB_RESPONSE); + break; + + case LAPB_UA: + lapb_dbg(1, "(%p) S2 RX UA(%d)\n", lapb->dev, frame->pf); + if (frame->pf) { + lapb_dbg(0, "(%p) S2 -> S0\n", lapb->dev); + lapb->state = LAPB_STATE_0; + lapb_start_t1timer(lapb); + lapb_stop_t2timer(lapb); + lapb_disconnect_confirmation(lapb, LAPB_OK); + } + break; + + case LAPB_DM: + lapb_dbg(1, "(%p) S2 RX DM(%d)\n", lapb->dev, frame->pf); + if (frame->pf) { + lapb_dbg(0, "(%p) S2 -> S0\n", lapb->dev); + lapb->state = LAPB_STATE_0; + lapb_start_t1timer(lapb); + lapb_stop_t2timer(lapb); + lapb_disconnect_confirmation(lapb, LAPB_NOTCONNECTED); + } + break; + + case LAPB_I: + case LAPB_REJ: + case LAPB_RNR: + case LAPB_RR: + lapb_dbg(1, "(%p) S2 RX {I,REJ,RNR,RR}(%d)\n", + lapb->dev, frame->pf); + lapb_dbg(1, "(%p) S2 RX DM(%d)\n", lapb->dev, frame->pf); + if (frame->pf) + lapb_send_control(lapb, LAPB_DM, frame->pf, + LAPB_RESPONSE); + break; + } + + kfree_skb(skb); +} + +/* + * State machine for state 3, Connected State. + * The handling of the timer(s) is in file lapb_timer.c + */ +static void lapb_state3_machine(struct lapb_cb *lapb, struct sk_buff *skb, + struct lapb_frame *frame) +{ + int queued = 0; + int modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : + LAPB_SMODULUS; + + switch (frame->type) { + case LAPB_SABM: + lapb_dbg(1, "(%p) S3 RX SABM(%d)\n", lapb->dev, frame->pf); + if (lapb->mode & LAPB_EXTENDED) { + lapb_dbg(1, "(%p) S3 TX DM(%d)\n", + lapb->dev, frame->pf); + lapb_send_control(lapb, LAPB_DM, frame->pf, + LAPB_RESPONSE); + } else { + lapb_dbg(1, "(%p) S3 TX UA(%d)\n", + lapb->dev, frame->pf); + lapb_send_control(lapb, LAPB_UA, frame->pf, + LAPB_RESPONSE); + lapb_stop_t1timer(lapb); + lapb_stop_t2timer(lapb); + lapb->condition = 0x00; + lapb->n2count = 0; + lapb->vs = 0; + lapb->vr = 0; + lapb->va = 0; + lapb_requeue_frames(lapb); + } + break; + + case LAPB_SABME: + lapb_dbg(1, "(%p) S3 RX SABME(%d)\n", lapb->dev, frame->pf); + if (lapb->mode & LAPB_EXTENDED) { + lapb_dbg(1, "(%p) S3 TX UA(%d)\n", + lapb->dev, frame->pf); + lapb_send_control(lapb, LAPB_UA, frame->pf, + LAPB_RESPONSE); + lapb_stop_t1timer(lapb); + lapb_stop_t2timer(lapb); + lapb->condition = 0x00; + lapb->n2count = 0; + lapb->vs = 0; + lapb->vr = 0; + lapb->va = 0; + lapb_requeue_frames(lapb); + } else { + lapb_dbg(1, "(%p) S3 TX DM(%d)\n", + lapb->dev, frame->pf); + lapb_send_control(lapb, LAPB_DM, frame->pf, + LAPB_RESPONSE); + } + break; + + case LAPB_DISC: + lapb_dbg(1, "(%p) S3 RX DISC(%d)\n", lapb->dev, frame->pf); + lapb_dbg(0, "(%p) S3 -> S0\n", lapb->dev); + lapb_clear_queues(lapb); + lapb_send_control(lapb, LAPB_UA, frame->pf, LAPB_RESPONSE); + lapb_start_t1timer(lapb); + lapb_stop_t2timer(lapb); + lapb->state = LAPB_STATE_0; + lapb_disconnect_indication(lapb, LAPB_OK); + break; + + case LAPB_DM: + lapb_dbg(1, "(%p) S3 RX DM(%d)\n", lapb->dev, frame->pf); + lapb_dbg(0, "(%p) S3 -> S0\n", lapb->dev); + lapb_clear_queues(lapb); + lapb->state = LAPB_STATE_0; + lapb_start_t1timer(lapb); + lapb_stop_t2timer(lapb); + lapb_disconnect_indication(lapb, LAPB_NOTCONNECTED); + break; + + case LAPB_RNR: + lapb_dbg(1, "(%p) S3 RX RNR(%d) R%d\n", + lapb->dev, frame->pf, frame->nr); + lapb->condition |= LAPB_PEER_RX_BUSY_CONDITION; + lapb_check_need_response(lapb, frame->cr, frame->pf); + if (lapb_validate_nr(lapb, frame->nr)) { + lapb_check_iframes_acked(lapb, frame->nr); + } else { + lapb->frmr_data = *frame; + lapb->frmr_type = LAPB_FRMR_Z; + lapb_transmit_frmr(lapb); + lapb_dbg(0, "(%p) S3 -> S4\n", lapb->dev); + lapb_start_t1timer(lapb); + lapb_stop_t2timer(lapb); + lapb->state = LAPB_STATE_4; + lapb->n2count = 0; + } + break; + + case LAPB_RR: + lapb_dbg(1, "(%p) S3 RX RR(%d) R%d\n", + lapb->dev, frame->pf, frame->nr); + lapb->condition &= ~LAPB_PEER_RX_BUSY_CONDITION; + lapb_check_need_response(lapb, frame->cr, frame->pf); + if (lapb_validate_nr(lapb, frame->nr)) { + lapb_check_iframes_acked(lapb, frame->nr); + } else { + lapb->frmr_data = *frame; + lapb->frmr_type = LAPB_FRMR_Z; + lapb_transmit_frmr(lapb); + lapb_dbg(0, "(%p) S3 -> S4\n", lapb->dev); + lapb_start_t1timer(lapb); + lapb_stop_t2timer(lapb); + lapb->state = LAPB_STATE_4; + lapb->n2count = 0; + } + break; + + case LAPB_REJ: + lapb_dbg(1, "(%p) S3 RX REJ(%d) R%d\n", + lapb->dev, frame->pf, frame->nr); + lapb->condition &= ~LAPB_PEER_RX_BUSY_CONDITION; + lapb_check_need_response(lapb, frame->cr, frame->pf); + if (lapb_validate_nr(lapb, frame->nr)) { + lapb_frames_acked(lapb, frame->nr); + lapb_stop_t1timer(lapb); + lapb->n2count = 0; + lapb_requeue_frames(lapb); + } else { + lapb->frmr_data = *frame; + lapb->frmr_type = LAPB_FRMR_Z; + lapb_transmit_frmr(lapb); + lapb_dbg(0, "(%p) S3 -> S4\n", lapb->dev); + lapb_start_t1timer(lapb); + lapb_stop_t2timer(lapb); + lapb->state = LAPB_STATE_4; + lapb->n2count = 0; + } + break; + + case LAPB_I: + lapb_dbg(1, "(%p) S3 RX I(%d) S%d R%d\n", + lapb->dev, frame->pf, frame->ns, frame->nr); + if (!lapb_validate_nr(lapb, frame->nr)) { + lapb->frmr_data = *frame; + lapb->frmr_type = LAPB_FRMR_Z; + lapb_transmit_frmr(lapb); + lapb_dbg(0, "(%p) S3 -> S4\n", lapb->dev); + lapb_start_t1timer(lapb); + lapb_stop_t2timer(lapb); + lapb->state = LAPB_STATE_4; + lapb->n2count = 0; + break; + } + if (lapb->condition & LAPB_PEER_RX_BUSY_CONDITION) + lapb_frames_acked(lapb, frame->nr); + else + lapb_check_iframes_acked(lapb, frame->nr); + + if (frame->ns == lapb->vr) { + int cn; + cn = lapb_data_indication(lapb, skb); + queued = 1; + /* + * If upper layer has dropped the frame, we + * basically ignore any further protocol + * processing. This will cause the peer + * to re-transmit the frame later like + * a frame lost on the wire. + */ + if (cn == NET_RX_DROP) { + pr_debug("rx congestion\n"); + break; + } + lapb->vr = (lapb->vr + 1) % modulus; + lapb->condition &= ~LAPB_REJECT_CONDITION; + if (frame->pf) + lapb_enquiry_response(lapb); + else { + if (!(lapb->condition & + LAPB_ACK_PENDING_CONDITION)) { + lapb->condition |= LAPB_ACK_PENDING_CONDITION; + lapb_start_t2timer(lapb); + } + } + } else { + if (lapb->condition & LAPB_REJECT_CONDITION) { + if (frame->pf) + lapb_enquiry_response(lapb); + } else { + lapb_dbg(1, "(%p) S3 TX REJ(%d) R%d\n", + lapb->dev, frame->pf, lapb->vr); + lapb->condition |= LAPB_REJECT_CONDITION; + lapb_send_control(lapb, LAPB_REJ, frame->pf, + LAPB_RESPONSE); + lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; + } + } + break; + + case LAPB_FRMR: + lapb_dbg(1, "(%p) S3 RX FRMR(%d) %5ph\n", + lapb->dev, frame->pf, + skb->data); + lapb_establish_data_link(lapb); + lapb_dbg(0, "(%p) S3 -> S1\n", lapb->dev); + lapb_requeue_frames(lapb); + lapb->state = LAPB_STATE_1; + break; + + case LAPB_ILLEGAL: + lapb_dbg(1, "(%p) S3 RX ILLEGAL(%d)\n", lapb->dev, frame->pf); + lapb->frmr_data = *frame; + lapb->frmr_type = LAPB_FRMR_W; + lapb_transmit_frmr(lapb); + lapb_dbg(0, "(%p) S3 -> S4\n", lapb->dev); + lapb_start_t1timer(lapb); + lapb_stop_t2timer(lapb); + lapb->state = LAPB_STATE_4; + lapb->n2count = 0; + break; + } + + if (!queued) + kfree_skb(skb); +} + +/* + * State machine for state 4, Frame Reject State. + * The handling of the timer(s) is in file lapb_timer.c. + */ +static void lapb_state4_machine(struct lapb_cb *lapb, struct sk_buff *skb, + struct lapb_frame *frame) +{ + switch (frame->type) { + case LAPB_SABM: + lapb_dbg(1, "(%p) S4 RX SABM(%d)\n", lapb->dev, frame->pf); + if (lapb->mode & LAPB_EXTENDED) { + lapb_dbg(1, "(%p) S4 TX DM(%d)\n", + lapb->dev, frame->pf); + lapb_send_control(lapb, LAPB_DM, frame->pf, + LAPB_RESPONSE); + } else { + lapb_dbg(1, "(%p) S4 TX UA(%d)\n", + lapb->dev, frame->pf); + lapb_dbg(0, "(%p) S4 -> S3\n", lapb->dev); + lapb_send_control(lapb, LAPB_UA, frame->pf, + LAPB_RESPONSE); + lapb_stop_t1timer(lapb); + lapb_stop_t2timer(lapb); + lapb->state = LAPB_STATE_3; + lapb->condition = 0x00; + lapb->n2count = 0; + lapb->vs = 0; + lapb->vr = 0; + lapb->va = 0; + lapb_connect_indication(lapb, LAPB_OK); + } + break; + + case LAPB_SABME: + lapb_dbg(1, "(%p) S4 RX SABME(%d)\n", lapb->dev, frame->pf); + if (lapb->mode & LAPB_EXTENDED) { + lapb_dbg(1, "(%p) S4 TX UA(%d)\n", + lapb->dev, frame->pf); + lapb_dbg(0, "(%p) S4 -> S3\n", lapb->dev); + lapb_send_control(lapb, LAPB_UA, frame->pf, + LAPB_RESPONSE); + lapb_stop_t1timer(lapb); + lapb_stop_t2timer(lapb); + lapb->state = LAPB_STATE_3; + lapb->condition = 0x00; + lapb->n2count = 0; + lapb->vs = 0; + lapb->vr = 0; + lapb->va = 0; + lapb_connect_indication(lapb, LAPB_OK); + } else { + lapb_dbg(1, "(%p) S4 TX DM(%d)\n", + lapb->dev, frame->pf); + lapb_send_control(lapb, LAPB_DM, frame->pf, + LAPB_RESPONSE); + } + break; + } + + kfree_skb(skb); +} + +/* + * Process an incoming LAPB frame + */ +void lapb_data_input(struct lapb_cb *lapb, struct sk_buff *skb) +{ + struct lapb_frame frame; + + if (lapb_decode(lapb, skb, &frame) < 0) { + kfree_skb(skb); + return; + } + + switch (lapb->state) { + case LAPB_STATE_0: + lapb_state0_machine(lapb, skb, &frame); break; + case LAPB_STATE_1: + lapb_state1_machine(lapb, skb, &frame); break; + case LAPB_STATE_2: + lapb_state2_machine(lapb, skb, &frame); break; + case LAPB_STATE_3: + lapb_state3_machine(lapb, skb, &frame); break; + case LAPB_STATE_4: + lapb_state4_machine(lapb, skb, &frame); break; + } + + lapb_kick(lapb); +} diff --git a/net/lapb/lapb_out.c b/net/lapb/lapb_out.c new file mode 100644 index 000000000..a966d29c7 --- /dev/null +++ b/net/lapb/lapb_out.c @@ -0,0 +1,205 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * LAPB release 002 + * + * This code REQUIRES 2.1.15 or higher/ NET3.038 + * + * History + * LAPB 001 Jonathan Naylor Started Coding + * LAPB 002 Jonathan Naylor New timer architecture. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#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/inet.h> +#include <linux/skbuff.h> +#include <linux/slab.h> +#include <net/sock.h> +#include <linux/uaccess.h> +#include <linux/fcntl.h> +#include <linux/mm.h> +#include <linux/interrupt.h> +#include <net/lapb.h> + +/* + * 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 lapb_send_iframe(struct lapb_cb *lapb, struct sk_buff *skb, int poll_bit) +{ + unsigned char *frame; + + if (!skb) + return; + + if (lapb->mode & LAPB_EXTENDED) { + frame = skb_push(skb, 2); + + frame[0] = LAPB_I; + frame[0] |= lapb->vs << 1; + frame[1] = poll_bit ? LAPB_EPF : 0; + frame[1] |= lapb->vr << 1; + } else { + frame = skb_push(skb, 1); + + *frame = LAPB_I; + *frame |= poll_bit ? LAPB_SPF : 0; + *frame |= lapb->vr << 5; + *frame |= lapb->vs << 1; + } + + lapb_dbg(1, "(%p) S%d TX I(%d) S%d R%d\n", + lapb->dev, lapb->state, poll_bit, lapb->vs, lapb->vr); + + lapb_transmit_buffer(lapb, skb, LAPB_COMMAND); +} + +void lapb_kick(struct lapb_cb *lapb) +{ + struct sk_buff *skb, *skbn; + unsigned short modulus, start, end; + + modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS; + start = !skb_peek(&lapb->ack_queue) ? lapb->va : lapb->vs; + end = (lapb->va + lapb->window) % modulus; + + if (!(lapb->condition & LAPB_PEER_RX_BUSY_CONDITION) && + start != end && skb_peek(&lapb->write_queue)) { + lapb->vs = start; + + /* + * Dequeue the frame and copy it. + */ + skb = skb_dequeue(&lapb->write_queue); + + do { + skbn = skb_copy(skb, GFP_ATOMIC); + if (!skbn) { + skb_queue_head(&lapb->write_queue, skb); + break; + } + + if (skb->sk) + skb_set_owner_w(skbn, skb->sk); + + /* + * Transmit the frame copy. + */ + lapb_send_iframe(lapb, skbn, LAPB_POLLOFF); + + lapb->vs = (lapb->vs + 1) % modulus; + + /* + * Requeue the original data frame. + */ + skb_queue_tail(&lapb->ack_queue, skb); + + } while (lapb->vs != end && (skb = skb_dequeue(&lapb->write_queue)) != NULL); + + lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; + + if (!lapb_t1timer_running(lapb)) + lapb_start_t1timer(lapb); + } +} + +void lapb_transmit_buffer(struct lapb_cb *lapb, struct sk_buff *skb, int type) +{ + unsigned char *ptr; + + ptr = skb_push(skb, 1); + + if (lapb->mode & LAPB_MLP) { + if (lapb->mode & LAPB_DCE) { + if (type == LAPB_COMMAND) + *ptr = LAPB_ADDR_C; + if (type == LAPB_RESPONSE) + *ptr = LAPB_ADDR_D; + } else { + if (type == LAPB_COMMAND) + *ptr = LAPB_ADDR_D; + if (type == LAPB_RESPONSE) + *ptr = LAPB_ADDR_C; + } + } else { + if (lapb->mode & LAPB_DCE) { + if (type == LAPB_COMMAND) + *ptr = LAPB_ADDR_A; + if (type == LAPB_RESPONSE) + *ptr = LAPB_ADDR_B; + } else { + if (type == LAPB_COMMAND) + *ptr = LAPB_ADDR_B; + if (type == LAPB_RESPONSE) + *ptr = LAPB_ADDR_A; + } + } + + lapb_dbg(2, "(%p) S%d TX %3ph\n", lapb->dev, lapb->state, skb->data); + + if (!lapb_data_transmit(lapb, skb)) + kfree_skb(skb); +} + +void lapb_establish_data_link(struct lapb_cb *lapb) +{ + lapb->condition = 0x00; + lapb->n2count = 0; + + if (lapb->mode & LAPB_EXTENDED) { + lapb_dbg(1, "(%p) S%d TX SABME(1)\n", lapb->dev, lapb->state); + lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND); + } else { + lapb_dbg(1, "(%p) S%d TX SABM(1)\n", lapb->dev, lapb->state); + lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND); + } + + lapb_start_t1timer(lapb); + lapb_stop_t2timer(lapb); +} + +void lapb_enquiry_response(struct lapb_cb *lapb) +{ + lapb_dbg(1, "(%p) S%d TX RR(1) R%d\n", + lapb->dev, lapb->state, lapb->vr); + + lapb_send_control(lapb, LAPB_RR, LAPB_POLLON, LAPB_RESPONSE); + + lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; +} + +void lapb_timeout_response(struct lapb_cb *lapb) +{ + lapb_dbg(1, "(%p) S%d TX RR(0) R%d\n", + lapb->dev, lapb->state, lapb->vr); + lapb_send_control(lapb, LAPB_RR, LAPB_POLLOFF, LAPB_RESPONSE); + + lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; +} + +void lapb_check_iframes_acked(struct lapb_cb *lapb, unsigned short nr) +{ + if (lapb->vs == nr) { + lapb_frames_acked(lapb, nr); + lapb_stop_t1timer(lapb); + lapb->n2count = 0; + } else if (lapb->va != nr) { + lapb_frames_acked(lapb, nr); + lapb_start_t1timer(lapb); + } +} + +void lapb_check_need_response(struct lapb_cb *lapb, int type, int pf) +{ + if (type == LAPB_COMMAND && pf) + lapb_enquiry_response(lapb); +} diff --git a/net/lapb/lapb_subr.c b/net/lapb/lapb_subr.c new file mode 100644 index 000000000..592a22d86 --- /dev/null +++ b/net/lapb/lapb_subr.c @@ -0,0 +1,299 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * LAPB release 002 + * + * This code REQUIRES 2.1.15 or higher/ NET3.038 + * + * History + * LAPB 001 Jonathan Naylor Started Coding + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#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/inet.h> +#include <linux/skbuff.h> +#include <linux/slab.h> +#include <net/sock.h> +#include <linux/uaccess.h> +#include <linux/fcntl.h> +#include <linux/mm.h> +#include <linux/interrupt.h> +#include <net/lapb.h> + +/* + * This routine purges all the queues of frames. + */ +void lapb_clear_queues(struct lapb_cb *lapb) +{ + skb_queue_purge(&lapb->write_queue); + skb_queue_purge(&lapb->ack_queue); +} + +/* + * This routine purges the input queue of those frames that have been + * acknowledged. This replaces the boxes labelled "V(a) <- N(r)" on the + * SDL diagram. + */ +void lapb_frames_acked(struct lapb_cb *lapb, unsigned short nr) +{ + struct sk_buff *skb; + int modulus; + + modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS; + + /* + * Remove all the ack-ed frames from the ack queue. + */ + if (lapb->va != nr) + while (skb_peek(&lapb->ack_queue) && lapb->va != nr) { + skb = skb_dequeue(&lapb->ack_queue); + kfree_skb(skb); + lapb->va = (lapb->va + 1) % modulus; + } +} + +void lapb_requeue_frames(struct lapb_cb *lapb) +{ + struct sk_buff *skb, *skb_prev = NULL; + + /* + * Requeue all the un-ack-ed frames on the output queue to be picked + * up by lapb_kick called from the timer. This arrangement handles the + * possibility of an empty output queue. + */ + while ((skb = skb_dequeue(&lapb->ack_queue)) != NULL) { + if (!skb_prev) + skb_queue_head(&lapb->write_queue, skb); + else + skb_append(skb_prev, skb, &lapb->write_queue); + skb_prev = skb; + } +} + +/* + * Validate that the value of nr is between va and vs. Return true or + * false for testing. + */ +int lapb_validate_nr(struct lapb_cb *lapb, unsigned short nr) +{ + unsigned short vc = lapb->va; + int modulus; + + modulus = (lapb->mode & LAPB_EXTENDED) ? LAPB_EMODULUS : LAPB_SMODULUS; + + while (vc != lapb->vs) { + if (nr == vc) + return 1; + vc = (vc + 1) % modulus; + } + + return nr == lapb->vs; +} + +/* + * This routine is the centralised routine for parsing the control + * information for the different frame formats. + */ +int lapb_decode(struct lapb_cb *lapb, struct sk_buff *skb, + struct lapb_frame *frame) +{ + frame->type = LAPB_ILLEGAL; + + lapb_dbg(2, "(%p) S%d RX %3ph\n", lapb->dev, lapb->state, skb->data); + + /* We always need to look at 2 bytes, sometimes we need + * to look at 3 and those cases are handled below. + */ + if (!pskb_may_pull(skb, 2)) + return -1; + + if (lapb->mode & LAPB_MLP) { + if (lapb->mode & LAPB_DCE) { + if (skb->data[0] == LAPB_ADDR_D) + frame->cr = LAPB_COMMAND; + if (skb->data[0] == LAPB_ADDR_C) + frame->cr = LAPB_RESPONSE; + } else { + if (skb->data[0] == LAPB_ADDR_C) + frame->cr = LAPB_COMMAND; + if (skb->data[0] == LAPB_ADDR_D) + frame->cr = LAPB_RESPONSE; + } + } else { + if (lapb->mode & LAPB_DCE) { + if (skb->data[0] == LAPB_ADDR_B) + frame->cr = LAPB_COMMAND; + if (skb->data[0] == LAPB_ADDR_A) + frame->cr = LAPB_RESPONSE; + } else { + if (skb->data[0] == LAPB_ADDR_A) + frame->cr = LAPB_COMMAND; + if (skb->data[0] == LAPB_ADDR_B) + frame->cr = LAPB_RESPONSE; + } + } + + skb_pull(skb, 1); + + if (lapb->mode & LAPB_EXTENDED) { + if (!(skb->data[0] & LAPB_S)) { + if (!pskb_may_pull(skb, 2)) + return -1; + /* + * I frame - carries NR/NS/PF + */ + frame->type = LAPB_I; + frame->ns = (skb->data[0] >> 1) & 0x7F; + frame->nr = (skb->data[1] >> 1) & 0x7F; + frame->pf = skb->data[1] & LAPB_EPF; + frame->control[0] = skb->data[0]; + frame->control[1] = skb->data[1]; + skb_pull(skb, 2); + } else if ((skb->data[0] & LAPB_U) == 1) { + if (!pskb_may_pull(skb, 2)) + return -1; + /* + * S frame - take out PF/NR + */ + frame->type = skb->data[0] & 0x0F; + frame->nr = (skb->data[1] >> 1) & 0x7F; + frame->pf = skb->data[1] & LAPB_EPF; + frame->control[0] = skb->data[0]; + frame->control[1] = skb->data[1]; + skb_pull(skb, 2); + } else if ((skb->data[0] & LAPB_U) == 3) { + /* + * U frame - take out PF + */ + frame->type = skb->data[0] & ~LAPB_SPF; + frame->pf = skb->data[0] & LAPB_SPF; + frame->control[0] = skb->data[0]; + frame->control[1] = 0x00; + skb_pull(skb, 1); + } + } else { + if (!(skb->data[0] & LAPB_S)) { + /* + * I frame - carries NR/NS/PF + */ + frame->type = LAPB_I; + frame->ns = (skb->data[0] >> 1) & 0x07; + frame->nr = (skb->data[0] >> 5) & 0x07; + frame->pf = skb->data[0] & LAPB_SPF; + } else if ((skb->data[0] & LAPB_U) == 1) { + /* + * S frame - take out PF/NR + */ + frame->type = skb->data[0] & 0x0F; + frame->nr = (skb->data[0] >> 5) & 0x07; + frame->pf = skb->data[0] & LAPB_SPF; + } else if ((skb->data[0] & LAPB_U) == 3) { + /* + * U frame - take out PF + */ + frame->type = skb->data[0] & ~LAPB_SPF; + frame->pf = skb->data[0] & LAPB_SPF; + } + + frame->control[0] = skb->data[0]; + + skb_pull(skb, 1); + } + + return 0; +} + +/* + * This routine is called when the HDLC layer internally generates a + * command or response for the remote machine ( eg. RR, UA etc. ). + * Only supervisory or unnumbered frames are processed, FRMRs are handled + * by lapb_transmit_frmr below. + */ +void lapb_send_control(struct lapb_cb *lapb, int frametype, + int poll_bit, int type) +{ + struct sk_buff *skb; + unsigned char *dptr; + + if ((skb = alloc_skb(LAPB_HEADER_LEN + 3, GFP_ATOMIC)) == NULL) + return; + + skb_reserve(skb, LAPB_HEADER_LEN + 1); + + if (lapb->mode & LAPB_EXTENDED) { + if ((frametype & LAPB_U) == LAPB_U) { + dptr = skb_put(skb, 1); + *dptr = frametype; + *dptr |= poll_bit ? LAPB_SPF : 0; + } else { + dptr = skb_put(skb, 2); + dptr[0] = frametype; + dptr[1] = (lapb->vr << 1); + dptr[1] |= poll_bit ? LAPB_EPF : 0; + } + } else { + dptr = skb_put(skb, 1); + *dptr = frametype; + *dptr |= poll_bit ? LAPB_SPF : 0; + if ((frametype & LAPB_U) == LAPB_S) /* S frames carry NR */ + *dptr |= (lapb->vr << 5); + } + + lapb_transmit_buffer(lapb, skb, type); +} + +/* + * This routine generates FRMRs based on information previously stored in + * the LAPB control block. + */ +void lapb_transmit_frmr(struct lapb_cb *lapb) +{ + struct sk_buff *skb; + unsigned char *dptr; + + if ((skb = alloc_skb(LAPB_HEADER_LEN + 7, GFP_ATOMIC)) == NULL) + return; + + skb_reserve(skb, LAPB_HEADER_LEN + 1); + + if (lapb->mode & LAPB_EXTENDED) { + dptr = skb_put(skb, 6); + *dptr++ = LAPB_FRMR; + *dptr++ = lapb->frmr_data.control[0]; + *dptr++ = lapb->frmr_data.control[1]; + *dptr++ = (lapb->vs << 1) & 0xFE; + *dptr = (lapb->vr << 1) & 0xFE; + if (lapb->frmr_data.cr == LAPB_RESPONSE) + *dptr |= 0x01; + dptr++; + *dptr++ = lapb->frmr_type; + + lapb_dbg(1, "(%p) S%d TX FRMR %5ph\n", + lapb->dev, lapb->state, + &skb->data[1]); + } else { + dptr = skb_put(skb, 4); + *dptr++ = LAPB_FRMR; + *dptr++ = lapb->frmr_data.control[0]; + *dptr = (lapb->vs << 1) & 0x0E; + *dptr |= (lapb->vr << 5) & 0xE0; + if (lapb->frmr_data.cr == LAPB_RESPONSE) + *dptr |= 0x10; + dptr++; + *dptr++ = lapb->frmr_type; + + lapb_dbg(1, "(%p) S%d TX FRMR %3ph\n", + lapb->dev, lapb->state, &skb->data[1]); + } + + lapb_transmit_buffer(lapb, skb, LAPB_RESPONSE); +} diff --git a/net/lapb/lapb_timer.c b/net/lapb/lapb_timer.c new file mode 100644 index 000000000..8f5b17001 --- /dev/null +++ b/net/lapb/lapb_timer.c @@ -0,0 +1,172 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * LAPB release 002 + * + * This code REQUIRES 2.1.15 or higher/ NET3.038 + * + * History + * LAPB 001 Jonathan Naylor Started Coding + * LAPB 002 Jonathan Naylor New timer architecture. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/errno.h> +#include <linux/types.h> +#include <linux/socket.h> +#include <linux/in.h> +#include <linux/kernel.h> +#include <linux/jiffies.h> +#include <linux/timer.h> +#include <linux/string.h> +#include <linux/sockios.h> +#include <linux/net.h> +#include <linux/inet.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/lapb.h> + +static void lapb_t1timer_expiry(struct timer_list *); +static void lapb_t2timer_expiry(struct timer_list *); + +void lapb_start_t1timer(struct lapb_cb *lapb) +{ + del_timer(&lapb->t1timer); + + lapb->t1timer.function = lapb_t1timer_expiry; + lapb->t1timer.expires = jiffies + lapb->t1; + + add_timer(&lapb->t1timer); +} + +void lapb_start_t2timer(struct lapb_cb *lapb) +{ + del_timer(&lapb->t2timer); + + lapb->t2timer.function = lapb_t2timer_expiry; + lapb->t2timer.expires = jiffies + lapb->t2; + + add_timer(&lapb->t2timer); +} + +void lapb_stop_t1timer(struct lapb_cb *lapb) +{ + del_timer(&lapb->t1timer); +} + +void lapb_stop_t2timer(struct lapb_cb *lapb) +{ + del_timer(&lapb->t2timer); +} + +int lapb_t1timer_running(struct lapb_cb *lapb) +{ + return timer_pending(&lapb->t1timer); +} + +static void lapb_t2timer_expiry(struct timer_list *t) +{ + struct lapb_cb *lapb = from_timer(lapb, t, t2timer); + + if (lapb->condition & LAPB_ACK_PENDING_CONDITION) { + lapb->condition &= ~LAPB_ACK_PENDING_CONDITION; + lapb_timeout_response(lapb); + } +} + +static void lapb_t1timer_expiry(struct timer_list *t) +{ + struct lapb_cb *lapb = from_timer(lapb, t, t1timer); + + switch (lapb->state) { + + /* + * If we are a DCE, keep going DM .. DM .. DM + */ + case LAPB_STATE_0: + if (lapb->mode & LAPB_DCE) + lapb_send_control(lapb, LAPB_DM, LAPB_POLLOFF, LAPB_RESPONSE); + break; + + /* + * Awaiting connection state, send SABM(E), up to N2 times. + */ + case LAPB_STATE_1: + if (lapb->n2count == lapb->n2) { + lapb_clear_queues(lapb); + lapb->state = LAPB_STATE_0; + lapb_disconnect_indication(lapb, LAPB_TIMEDOUT); + lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev); + return; + } else { + lapb->n2count++; + if (lapb->mode & LAPB_EXTENDED) { + lapb_dbg(1, "(%p) S1 TX SABME(1)\n", + lapb->dev); + lapb_send_control(lapb, LAPB_SABME, LAPB_POLLON, LAPB_COMMAND); + } else { + lapb_dbg(1, "(%p) S1 TX SABM(1)\n", + lapb->dev); + lapb_send_control(lapb, LAPB_SABM, LAPB_POLLON, LAPB_COMMAND); + } + } + break; + + /* + * Awaiting disconnection state, send DISC, up to N2 times. + */ + case LAPB_STATE_2: + if (lapb->n2count == lapb->n2) { + lapb_clear_queues(lapb); + lapb->state = LAPB_STATE_0; + lapb_disconnect_confirmation(lapb, LAPB_TIMEDOUT); + lapb_dbg(0, "(%p) S2 -> S0\n", lapb->dev); + return; + } else { + lapb->n2count++; + lapb_dbg(1, "(%p) S2 TX DISC(1)\n", lapb->dev); + lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND); + } + break; + + /* + * Data transfer state, restransmit I frames, up to N2 times. + */ + case LAPB_STATE_3: + if (lapb->n2count == lapb->n2) { + lapb_clear_queues(lapb); + lapb->state = LAPB_STATE_0; + lapb_stop_t2timer(lapb); + lapb_disconnect_indication(lapb, LAPB_TIMEDOUT); + lapb_dbg(0, "(%p) S3 -> S0\n", lapb->dev); + return; + } else { + lapb->n2count++; + lapb_requeue_frames(lapb); + lapb_kick(lapb); + } + break; + + /* + * Frame reject state, restransmit FRMR frames, up to N2 times. + */ + case LAPB_STATE_4: + if (lapb->n2count == lapb->n2) { + lapb_clear_queues(lapb); + lapb->state = LAPB_STATE_0; + lapb_disconnect_indication(lapb, LAPB_TIMEDOUT); + lapb_dbg(0, "(%p) S4 -> S0\n", lapb->dev); + return; + } else { + lapb->n2count++; + lapb_transmit_frmr(lapb); + } + break; + } + + lapb_start_t1timer(lapb); +} |