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![Thomas Gleixner](/assets/img/avatar_default.png)
Based on 1 normalized pattern(s): this module is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 18 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190520170858.008906948@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
226 lines
5.1 KiB
C
226 lines
5.1 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* X.25 Packet Layer release 002
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*
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* This is ALPHA test software. This code may break your machine,
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* randomly fail to work with new releases, misbehave and/or generally
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* screw up. It might even work.
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*
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* This code REQUIRES 2.1.15 or higher
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*
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* History
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* X.25 001 Jonathan Naylor Started coding.
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* X.25 002 Jonathan Naylor New timer architecture.
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* 2000-09-04 Henner Eisen Prevented x25_output() skb leakage.
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* 2000-10-27 Henner Eisen MSG_DONTWAIT for fragment allocation.
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* 2000-11-10 Henner Eisen x25_send_iframe(): re-queued frames
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* needed cleaned seq-number fields.
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*/
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#include <linux/slab.h>
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#include <linux/socket.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/skbuff.h>
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#include <net/sock.h>
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#include <net/x25.h>
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static int x25_pacsize_to_bytes(unsigned int pacsize)
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{
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int bytes = 1;
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if (!pacsize)
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return 128;
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while (pacsize-- > 0)
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bytes *= 2;
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return bytes;
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}
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/*
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* This is where all X.25 information frames pass.
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*
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* Returns the amount of user data bytes sent on success
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* or a negative error code on failure.
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*/
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int x25_output(struct sock *sk, struct sk_buff *skb)
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{
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struct sk_buff *skbn;
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unsigned char header[X25_EXT_MIN_LEN];
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int err, frontlen, len;
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int sent=0, noblock = X25_SKB_CB(skb)->flags & MSG_DONTWAIT;
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struct x25_sock *x25 = x25_sk(sk);
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int header_len = x25->neighbour->extended ? X25_EXT_MIN_LEN :
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X25_STD_MIN_LEN;
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int max_len = x25_pacsize_to_bytes(x25->facilities.pacsize_out);
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if (skb->len - header_len > max_len) {
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/* Save a copy of the Header */
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skb_copy_from_linear_data(skb, header, header_len);
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skb_pull(skb, header_len);
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frontlen = skb_headroom(skb);
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while (skb->len > 0) {
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release_sock(sk);
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skbn = sock_alloc_send_skb(sk, frontlen + max_len,
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noblock, &err);
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lock_sock(sk);
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if (!skbn) {
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if (err == -EWOULDBLOCK && noblock){
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kfree_skb(skb);
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return sent;
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}
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SOCK_DEBUG(sk, "x25_output: fragment alloc"
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" failed, err=%d, %d bytes "
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"sent\n", err, sent);
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return err;
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}
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skb_reserve(skbn, frontlen);
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len = max_len > skb->len ? skb->len : max_len;
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/* Copy the user data */
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skb_copy_from_linear_data(skb, skb_put(skbn, len), len);
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skb_pull(skb, len);
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/* Duplicate the Header */
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skb_push(skbn, header_len);
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skb_copy_to_linear_data(skbn, header, header_len);
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if (skb->len > 0) {
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if (x25->neighbour->extended)
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skbn->data[3] |= X25_EXT_M_BIT;
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else
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skbn->data[2] |= X25_STD_M_BIT;
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}
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skb_queue_tail(&sk->sk_write_queue, skbn);
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sent += len;
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}
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kfree_skb(skb);
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} else {
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skb_queue_tail(&sk->sk_write_queue, skb);
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sent = skb->len - header_len;
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}
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return sent;
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}
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/*
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* This procedure is passed a buffer descriptor for an iframe. It builds
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* the rest of the control part of the frame and then writes it out.
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*/
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static void x25_send_iframe(struct sock *sk, struct sk_buff *skb)
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{
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struct x25_sock *x25 = x25_sk(sk);
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if (!skb)
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return;
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if (x25->neighbour->extended) {
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skb->data[2] = (x25->vs << 1) & 0xFE;
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skb->data[3] &= X25_EXT_M_BIT;
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skb->data[3] |= (x25->vr << 1) & 0xFE;
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} else {
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skb->data[2] &= X25_STD_M_BIT;
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skb->data[2] |= (x25->vs << 1) & 0x0E;
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skb->data[2] |= (x25->vr << 5) & 0xE0;
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}
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x25_transmit_link(skb, x25->neighbour);
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}
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void x25_kick(struct sock *sk)
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{
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struct sk_buff *skb, *skbn;
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unsigned short start, end;
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int modulus;
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struct x25_sock *x25 = x25_sk(sk);
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if (x25->state != X25_STATE_3)
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return;
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/*
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* Transmit interrupt data.
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*/
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if (skb_peek(&x25->interrupt_out_queue) != NULL &&
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!test_and_set_bit(X25_INTERRUPT_FLAG, &x25->flags)) {
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skb = skb_dequeue(&x25->interrupt_out_queue);
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x25_transmit_link(skb, x25->neighbour);
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}
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if (x25->condition & X25_COND_PEER_RX_BUSY)
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return;
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if (!skb_peek(&sk->sk_write_queue))
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return;
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modulus = x25->neighbour->extended ? X25_EMODULUS : X25_SMODULUS;
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start = skb_peek(&x25->ack_queue) ? x25->vs : x25->va;
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end = (x25->va + x25->facilities.winsize_out) % modulus;
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if (start == end)
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return;
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x25->vs = start;
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/*
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* Transmit data until either we're out of data to send or
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* the window is full.
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*/
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skb = skb_dequeue(&sk->sk_write_queue);
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do {
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if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
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skb_queue_head(&sk->sk_write_queue, skb);
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break;
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}
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skb_set_owner_w(skbn, sk);
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/*
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* Transmit the frame copy.
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*/
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x25_send_iframe(sk, skbn);
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x25->vs = (x25->vs + 1) % modulus;
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/*
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* Requeue the original data frame.
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*/
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skb_queue_tail(&x25->ack_queue, skb);
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} while (x25->vs != end &&
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(skb = skb_dequeue(&sk->sk_write_queue)) != NULL);
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x25->vl = x25->vr;
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x25->condition &= ~X25_COND_ACK_PENDING;
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x25_stop_timer(sk);
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}
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/*
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* The following routines are taken from page 170 of the 7th ARRL Computer
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* Networking Conference paper, as is the whole state machine.
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*/
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void x25_enquiry_response(struct sock *sk)
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{
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struct x25_sock *x25 = x25_sk(sk);
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if (x25->condition & X25_COND_OWN_RX_BUSY)
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x25_write_internal(sk, X25_RNR);
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else
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x25_write_internal(sk, X25_RR);
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x25->vl = x25->vr;
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x25->condition &= ~X25_COND_ACK_PENDING;
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x25_stop_timer(sk);
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}
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