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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:49:45 +0000 |
commit | 2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch) | |
tree | 848558de17fb3008cdf4d861b01ac7781903ce39 /net/ax25/ax25_out.c | |
parent | Initial commit. (diff) | |
download | linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip |
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'net/ax25/ax25_out.c')
-rw-r--r-- | net/ax25/ax25_out.c | 386 |
1 files changed, 386 insertions, 0 deletions
diff --git a/net/ax25/ax25_out.c b/net/ax25/ax25_out.c new file mode 100644 index 000000000..3db76d247 --- /dev/null +++ b/net/ax25/ax25_out.c @@ -0,0 +1,386 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * + * Copyright (C) Alan Cox GW4PTS (alan@lxorguk.ukuu.org.uk) + * 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/module.h> +#include <linux/timer.h> +#include <linux/string.h> +#include <linux/sockios.h> +#include <linux/spinlock.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> + +static DEFINE_SPINLOCK(ax25_frag_lock); + +ax25_cb *ax25_send_frame(struct sk_buff *skb, int paclen, const ax25_address *src, ax25_address *dest, ax25_digi *digi, struct net_device *dev) +{ + ax25_dev *ax25_dev; + ax25_cb *ax25; + + /* + * Take the default packet length for the device if zero is + * specified. + */ + if (paclen == 0) { + if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) + return NULL; + + paclen = ax25_dev->values[AX25_VALUES_PACLEN]; + } + + /* + * Look for an existing connection. + */ + if ((ax25 = ax25_find_cb(src, dest, digi, dev)) != NULL) { + ax25_output(ax25, paclen, skb); + return ax25; /* It already existed */ + } + + if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL) + return NULL; + + if ((ax25 = ax25_create_cb()) == NULL) + return NULL; + + ax25_fillin_cb(ax25, ax25_dev); + + ax25->source_addr = *src; + ax25->dest_addr = *dest; + + if (digi != NULL) { + ax25->digipeat = kmemdup(digi, sizeof(*digi), GFP_ATOMIC); + if (ax25->digipeat == NULL) { + ax25_cb_put(ax25); + return NULL; + } + } + + switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) { + case AX25_PROTO_STD_SIMPLEX: + case AX25_PROTO_STD_DUPLEX: + ax25_std_establish_data_link(ax25); + break; + +#ifdef CONFIG_AX25_DAMA_SLAVE + case AX25_PROTO_DAMA_SLAVE: + if (ax25_dev->dama.slave) + ax25_ds_establish_data_link(ax25); + else + ax25_std_establish_data_link(ax25); + break; +#endif + } + + /* + * There is one ref for the state machine; a caller needs + * one more to put it back, just like with the existing one. + */ + ax25_cb_hold(ax25); + + ax25_cb_add(ax25); + + ax25->state = AX25_STATE_1; + + ax25_start_heartbeat(ax25); + + ax25_output(ax25, paclen, skb); + + return ax25; /* We had to create it */ +} + +EXPORT_SYMBOL(ax25_send_frame); + +/* + * All outgoing AX.25 I frames pass via this routine. Therefore this is + * where the fragmentation of frames takes place. If fragment is set to + * zero then we are not allowed to do fragmentation, even if the frame + * is too large. + */ +void ax25_output(ax25_cb *ax25, int paclen, struct sk_buff *skb) +{ + struct sk_buff *skbn; + unsigned char *p; + int frontlen, len, fragno, ka9qfrag, first = 1; + + if (paclen < 16) { + WARN_ON_ONCE(1); + kfree_skb(skb); + return; + } + + if ((skb->len - 1) > paclen) { + if (*skb->data == AX25_P_TEXT) { + skb_pull(skb, 1); /* skip PID */ + ka9qfrag = 0; + } else { + paclen -= 2; /* Allow for fragment control info */ + ka9qfrag = 1; + } + + fragno = skb->len / paclen; + if (skb->len % paclen == 0) fragno--; + + frontlen = skb_headroom(skb); /* Address space + CTRL */ + + while (skb->len > 0) { + spin_lock_bh(&ax25_frag_lock); + if ((skbn = alloc_skb(paclen + 2 + frontlen, GFP_ATOMIC)) == NULL) { + spin_unlock_bh(&ax25_frag_lock); + printk(KERN_CRIT "AX.25: ax25_output - out of memory\n"); + return; + } + + if (skb->sk != NULL) + skb_set_owner_w(skbn, skb->sk); + + spin_unlock_bh(&ax25_frag_lock); + + len = (paclen > skb->len) ? skb->len : paclen; + + if (ka9qfrag == 1) { + skb_reserve(skbn, frontlen + 2); + skb_set_network_header(skbn, + skb_network_offset(skb)); + skb_copy_from_linear_data(skb, skb_put(skbn, len), len); + p = skb_push(skbn, 2); + + *p++ = AX25_P_SEGMENT; + + *p = fragno--; + if (first) { + *p |= AX25_SEG_FIRST; + first = 0; + } + } else { + skb_reserve(skbn, frontlen + 1); + skb_set_network_header(skbn, + skb_network_offset(skb)); + skb_copy_from_linear_data(skb, skb_put(skbn, len), 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 */ + } + + kfree_skb(skb); + } else { + skb_queue_tail(&ax25->write_queue, skb); /* Throw it on the queue */ + } + + switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) { + case AX25_PROTO_STD_SIMPLEX: + case AX25_PROTO_STD_DUPLEX: + ax25_kick(ax25); + break; + +#ifdef CONFIG_AX25_DAMA_SLAVE + /* + * A DAMA slave is _required_ to work as normal AX.25L2V2 + * if no DAMA master is available. + */ + case AX25_PROTO_DAMA_SLAVE: + if (!ax25->ax25_dev->dama.slave) ax25_kick(ax25); + break; +#endif + } +} + +/* + * 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 ax25_send_iframe(ax25_cb *ax25, struct sk_buff *skb, int poll_bit) +{ + unsigned char *frame; + + if (skb == NULL) + return; + + skb_reset_network_header(skb); + + if (ax25->modulus == AX25_MODULUS) { + frame = skb_push(skb, 1); + + *frame = AX25_I; + *frame |= (poll_bit) ? AX25_PF : 0; + *frame |= (ax25->vr << 5); + *frame |= (ax25->vs << 1); + } else { + frame = skb_push(skb, 2); + + frame[0] = AX25_I; + frame[0] |= (ax25->vs << 1); + frame[1] = (poll_bit) ? AX25_EPF : 0; + frame[1] |= (ax25->vr << 1); + } + + ax25_start_idletimer(ax25); + + ax25_transmit_buffer(ax25, skb, AX25_COMMAND); +} + +void ax25_kick(ax25_cb *ax25) +{ + struct sk_buff *skb, *skbn; + int last = 1; + unsigned short start, end, next; + + if (ax25->state != AX25_STATE_3 && ax25->state != AX25_STATE_4) + return; + + if (ax25->condition & AX25_COND_PEER_RX_BUSY) + return; + + if (skb_peek(&ax25->write_queue) == NULL) + return; + + start = (skb_peek(&ax25->ack_queue) == NULL) ? ax25->va : ax25->vs; + end = (ax25->va + ax25->window) % ax25->modulus; + + if (start == end) + return; + + /* + * Transmit data until either we're out of data to send or + * the window is full. Send a poll on the final I frame if + * the window is filled. + */ + + /* + * Dequeue the frame and copy it. + * Check for race with ax25_clear_queues(). + */ + skb = skb_dequeue(&ax25->write_queue); + if (!skb) + return; + + ax25->vs = start; + + do { + if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) { + skb_queue_head(&ax25->write_queue, skb); + break; + } + + if (skb->sk != NULL) + skb_set_owner_w(skbn, skb->sk); + + next = (ax25->vs + 1) % ax25->modulus; + last = (next == end); + + /* + * Transmit the frame copy. + * bke 960114: do not set the Poll bit on the last frame + * in DAMA mode. + */ + switch (ax25->ax25_dev->values[AX25_VALUES_PROTOCOL]) { + case AX25_PROTO_STD_SIMPLEX: + case AX25_PROTO_STD_DUPLEX: + ax25_send_iframe(ax25, skbn, (last) ? AX25_POLLON : AX25_POLLOFF); + break; + +#ifdef CONFIG_AX25_DAMA_SLAVE + case AX25_PROTO_DAMA_SLAVE: + ax25_send_iframe(ax25, skbn, AX25_POLLOFF); + break; +#endif + } + + ax25->vs = next; + + /* + * Requeue the original data frame. + */ + skb_queue_tail(&ax25->ack_queue, skb); + + } while (!last && (skb = skb_dequeue(&ax25->write_queue)) != NULL); + + ax25->condition &= ~AX25_COND_ACK_PENDING; + + if (!ax25_t1timer_running(ax25)) { + ax25_stop_t3timer(ax25); + ax25_calculate_t1(ax25); + ax25_start_t1timer(ax25); + } +} + +void ax25_transmit_buffer(ax25_cb *ax25, struct sk_buff *skb, int type) +{ + unsigned char *ptr; + int headroom; + + if (ax25->ax25_dev == NULL) { + ax25_disconnect(ax25, ENETUNREACH); + return; + } + + headroom = ax25_addr_size(ax25->digipeat); + + if (unlikely(skb_headroom(skb) < headroom)) { + skb = skb_expand_head(skb, headroom); + if (!skb) { + printk(KERN_CRIT "AX.25: ax25_transmit_buffer - out of memory\n"); + return; + } + } + + ptr = skb_push(skb, headroom); + + ax25_addr_build(ptr, &ax25->source_addr, &ax25->dest_addr, ax25->digipeat, type, ax25->modulus); + + ax25_queue_xmit(skb, ax25->ax25_dev->dev); +} + +/* + * A small shim to dev_queue_xmit to add the KISS control byte, and do + * any packet forwarding in operation. + */ +void ax25_queue_xmit(struct sk_buff *skb, struct net_device *dev) +{ + unsigned char *ptr; + + skb->protocol = ax25_type_trans(skb, ax25_fwd_dev(dev)); + + ptr = skb_push(skb, 1); + *ptr = 0x00; /* KISS */ + + dev_queue_xmit(skb); +} + +int ax25_check_iframes_acked(ax25_cb *ax25, unsigned short nr) +{ + if (ax25->vs == nr) { + ax25_frames_acked(ax25, nr); + ax25_calculate_rtt(ax25); + ax25_stop_t1timer(ax25); + ax25_start_t3timer(ax25); + return 1; + } else { + if (ax25->va != nr) { + ax25_frames_acked(ax25, nr); + ax25_calculate_t1(ax25); + ax25_start_t1timer(ax25); + return 1; + } + } + return 0; +} |