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![Zhang Qilong](/assets/img/avatar_default.png)
The syzkaller reported an issue: KASAN: null-ptr-deref in range [0x0000000000000380-0x0000000000000387] CPU: 0 PID: 4069 Comm: kworker/0:15 Not tainted 6.0.0-syzkaller-02734-g0326074ff465 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 Workqueue: rcu_gp srcu_invoke_callbacks RIP: 0010:rose_send_frame+0x1dd/0x2f0 net/rose/rose_link.c:101 Call Trace: <IRQ> rose_transmit_clear_request+0x1d5/0x290 net/rose/rose_link.c:255 rose_rx_call_request+0x4c0/0x1bc0 net/rose/af_rose.c:1009 rose_loopback_timer+0x19e/0x590 net/rose/rose_loopback.c:111 call_timer_fn+0x1a0/0x6b0 kernel/time/timer.c:1474 expire_timers kernel/time/timer.c:1519 [inline] __run_timers.part.0+0x674/0xa80 kernel/time/timer.c:1790 __run_timers kernel/time/timer.c:1768 [inline] run_timer_softirq+0xb3/0x1d0 kernel/time/timer.c:1803 __do_softirq+0x1d0/0x9c8 kernel/softirq.c:571 [...] </IRQ> It triggers NULL pointer dereference when 'neigh->dev->dev_addr' is called in the rose_send_frame(). It's the first occurrence of the `neigh` is in rose_loopback_timer() as `rose_loopback_neigh', and the 'dev' in 'rose_loopback_neigh' is initialized sa nullptr. It had been fixed by commit3b3fd068c5
("rose: Fix Null pointer dereference in rose_send_frame()") ever. But it's introduced by commit3c53cd65de
("rose: check NULL rose_loopback_neigh->loopback") again. We fix it by add NULL check in rose_transmit_clear_request(). When the 'dev' in 'neigh' is NULL, we don't reply the request and just clear it. syzkaller don't provide repro, and I provide a syz repro like: r0 = syz_init_net_socket$bt_sco(0x1f, 0x5, 0x2) ioctl$sock_inet_SIOCSIFFLAGS(r0, 0x8914, &(0x7f0000000180)={'rose0\x00', 0x201}) r1 = syz_init_net_socket$rose(0xb, 0x5, 0x0) bind$rose(r1, &(0x7f00000000c0)=@full={0xb, @dev, @null, 0x0, [@null, @null, @netrom, @netrom, @default, @null]}, 0x40) connect$rose(r1, &(0x7f0000000240)=@short={0xb, @dev={0xbb, 0xbb, 0xbb, 0x1, 0x0}, @remote={0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0xcc, 0x1}, 0x1, @netrom={0xbb, 0xbb, 0xbb, 0xbb, 0xbb, 0x0, 0x0}}, 0x1c) Fixes:3c53cd65de
("rose: check NULL rose_loopback_neigh->loopback") Signed-off-by: Zhang Qilong <zhangqilong3@huawei.com> Signed-off-by: David S. Miller <davem@davemloft.net>
289 lines
6.5 KiB
C
289 lines
6.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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*
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* Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
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*/
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#include <linux/errno.h>
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#include <linux/types.h>
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#include <linux/socket.h>
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#include <linux/in.h>
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#include <linux/kernel.h>
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#include <linux/jiffies.h>
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#include <linux/timer.h>
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#include <linux/string.h>
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#include <linux/sockios.h>
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#include <linux/net.h>
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#include <linux/slab.h>
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#include <net/ax25.h>
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#include <linux/inet.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <net/sock.h>
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#include <linux/fcntl.h>
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#include <linux/mm.h>
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#include <linux/interrupt.h>
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#include <net/rose.h>
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static void rose_ftimer_expiry(struct timer_list *);
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static void rose_t0timer_expiry(struct timer_list *);
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static void rose_transmit_restart_confirmation(struct rose_neigh *neigh);
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static void rose_transmit_restart_request(struct rose_neigh *neigh);
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void rose_start_ftimer(struct rose_neigh *neigh)
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{
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del_timer(&neigh->ftimer);
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neigh->ftimer.function = rose_ftimer_expiry;
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neigh->ftimer.expires =
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jiffies + msecs_to_jiffies(sysctl_rose_link_fail_timeout);
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add_timer(&neigh->ftimer);
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}
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static void rose_start_t0timer(struct rose_neigh *neigh)
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{
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del_timer(&neigh->t0timer);
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neigh->t0timer.function = rose_t0timer_expiry;
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neigh->t0timer.expires =
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jiffies + msecs_to_jiffies(sysctl_rose_restart_request_timeout);
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add_timer(&neigh->t0timer);
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}
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void rose_stop_ftimer(struct rose_neigh *neigh)
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{
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del_timer(&neigh->ftimer);
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}
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void rose_stop_t0timer(struct rose_neigh *neigh)
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{
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del_timer(&neigh->t0timer);
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}
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int rose_ftimer_running(struct rose_neigh *neigh)
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{
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return timer_pending(&neigh->ftimer);
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}
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static int rose_t0timer_running(struct rose_neigh *neigh)
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{
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return timer_pending(&neigh->t0timer);
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}
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static void rose_ftimer_expiry(struct timer_list *t)
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{
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}
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static void rose_t0timer_expiry(struct timer_list *t)
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{
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struct rose_neigh *neigh = from_timer(neigh, t, t0timer);
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rose_transmit_restart_request(neigh);
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neigh->dce_mode = 0;
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rose_start_t0timer(neigh);
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}
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/*
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* Interface to ax25_send_frame. Changes my level 2 callsign depending
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* on whether we have a global ROSE callsign or use the default port
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* callsign.
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*/
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static int rose_send_frame(struct sk_buff *skb, struct rose_neigh *neigh)
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{
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const ax25_address *rose_call;
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ax25_cb *ax25s;
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if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
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rose_call = (const ax25_address *)neigh->dev->dev_addr;
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else
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rose_call = &rose_callsign;
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ax25s = neigh->ax25;
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neigh->ax25 = ax25_send_frame(skb, 260, rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
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if (ax25s)
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ax25_cb_put(ax25s);
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return neigh->ax25 != NULL;
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}
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/*
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* Interface to ax25_link_up. Changes my level 2 callsign depending
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* on whether we have a global ROSE callsign or use the default port
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* callsign.
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*/
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static int rose_link_up(struct rose_neigh *neigh)
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{
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const ax25_address *rose_call;
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ax25_cb *ax25s;
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if (ax25cmp(&rose_callsign, &null_ax25_address) == 0)
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rose_call = (const ax25_address *)neigh->dev->dev_addr;
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else
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rose_call = &rose_callsign;
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ax25s = neigh->ax25;
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neigh->ax25 = ax25_find_cb(rose_call, &neigh->callsign, neigh->digipeat, neigh->dev);
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if (ax25s)
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ax25_cb_put(ax25s);
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return neigh->ax25 != NULL;
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}
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/*
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* This handles all restart and diagnostic frames.
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*/
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void rose_link_rx_restart(struct sk_buff *skb, struct rose_neigh *neigh, unsigned short frametype)
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{
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struct sk_buff *skbn;
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switch (frametype) {
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case ROSE_RESTART_REQUEST:
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rose_stop_t0timer(neigh);
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neigh->restarted = 1;
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neigh->dce_mode = (skb->data[3] == ROSE_DTE_ORIGINATED);
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rose_transmit_restart_confirmation(neigh);
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break;
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case ROSE_RESTART_CONFIRMATION:
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rose_stop_t0timer(neigh);
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neigh->restarted = 1;
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break;
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case ROSE_DIAGNOSTIC:
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pr_warn("ROSE: received diagnostic #%d - %3ph\n", skb->data[3],
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skb->data + 4);
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break;
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default:
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printk(KERN_WARNING "ROSE: received unknown %02X with LCI 000\n", frametype);
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break;
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}
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if (neigh->restarted) {
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while ((skbn = skb_dequeue(&neigh->queue)) != NULL)
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if (!rose_send_frame(skbn, neigh))
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kfree_skb(skbn);
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}
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}
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/*
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* This routine is called when a Restart Request is needed
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*/
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static void rose_transmit_restart_request(struct rose_neigh *neigh)
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{
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struct sk_buff *skb;
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unsigned char *dptr;
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int len;
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len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 3;
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if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
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return;
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skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
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dptr = skb_put(skb, ROSE_MIN_LEN + 3);
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*dptr++ = AX25_P_ROSE;
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*dptr++ = ROSE_GFI;
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*dptr++ = 0x00;
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*dptr++ = ROSE_RESTART_REQUEST;
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*dptr++ = ROSE_DTE_ORIGINATED;
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*dptr++ = 0;
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if (!rose_send_frame(skb, neigh))
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kfree_skb(skb);
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}
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/*
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* This routine is called when a Restart Confirmation is needed
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*/
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static void rose_transmit_restart_confirmation(struct rose_neigh *neigh)
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{
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struct sk_buff *skb;
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unsigned char *dptr;
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int len;
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len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 1;
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if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
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return;
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skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
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dptr = skb_put(skb, ROSE_MIN_LEN + 1);
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*dptr++ = AX25_P_ROSE;
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*dptr++ = ROSE_GFI;
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*dptr++ = 0x00;
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*dptr++ = ROSE_RESTART_CONFIRMATION;
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if (!rose_send_frame(skb, neigh))
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kfree_skb(skb);
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}
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/*
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* This routine is called when a Clear Request is needed outside of the context
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* of a connected socket.
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*/
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void rose_transmit_clear_request(struct rose_neigh *neigh, unsigned int lci, unsigned char cause, unsigned char diagnostic)
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{
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struct sk_buff *skb;
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unsigned char *dptr;
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int len;
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if (!neigh->dev)
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return;
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len = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN + 3;
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if ((skb = alloc_skb(len, GFP_ATOMIC)) == NULL)
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return;
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skb_reserve(skb, AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN);
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dptr = skb_put(skb, ROSE_MIN_LEN + 3);
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*dptr++ = AX25_P_ROSE;
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*dptr++ = ((lci >> 8) & 0x0F) | ROSE_GFI;
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*dptr++ = ((lci >> 0) & 0xFF);
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*dptr++ = ROSE_CLEAR_REQUEST;
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*dptr++ = cause;
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*dptr++ = diagnostic;
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if (!rose_send_frame(skb, neigh))
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kfree_skb(skb);
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}
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void rose_transmit_link(struct sk_buff *skb, struct rose_neigh *neigh)
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{
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unsigned char *dptr;
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if (neigh->loopback) {
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rose_loopback_queue(skb, neigh);
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return;
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}
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if (!rose_link_up(neigh))
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neigh->restarted = 0;
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dptr = skb_push(skb, 1);
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*dptr++ = AX25_P_ROSE;
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if (neigh->restarted) {
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if (!rose_send_frame(skb, neigh))
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kfree_skb(skb);
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} else {
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skb_queue_tail(&neigh->queue, skb);
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if (!rose_t0timer_running(neigh)) {
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rose_transmit_restart_request(neigh);
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neigh->dce_mode = 0;
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rose_start_t0timer(neigh);
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}
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}
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}
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