![Randy Dunlap](/assets/img/avatar_default.png)
net: Use <linux/capability.h> where capable() is used. Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
371 lines
11 KiB
C
371 lines
11 KiB
C
/* net/atm/pppoatm.c - RFC2364 PPP over ATM/AAL5 */
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/* Copyright 1999-2000 by Mitchell Blank Jr */
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/* Based on clip.c; 1995-1999 by Werner Almesberger, EPFL LRC/ICA */
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/* And on ppp_async.c; Copyright 1999 Paul Mackerras */
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/* And help from Jens Axboe */
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/*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* This driver provides the encapsulation and framing for sending
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* and receiving PPP frames in ATM AAL5 PDUs.
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*/
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/*
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* One shortcoming of this driver is that it does not comply with
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* section 8 of RFC2364 - we are supposed to detect a change
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* in encapsulation and immediately abort the connection (in order
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* to avoid a black-hole being created if our peer loses state
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* and changes encapsulation unilaterally. However, since the
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* ppp_generic layer actually does the decapsulation, we need
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* a way of notifying it when we _think_ there might be a problem)
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* There's two cases:
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* 1. LLC-encapsulation was missing when it was enabled. In
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* this case, we should tell the upper layer "tear down
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* this session if this skb looks ok to you"
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* 2. LLC-encapsulation was present when it was disabled. Then
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* we need to tell the upper layer "this packet may be
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* ok, but if its in error tear down the session"
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* These hooks are not yet available in ppp_generic
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*/
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#include <linux/module.h>
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#include <linux/config.h>
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#include <linux/init.h>
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#include <linux/skbuff.h>
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#include <linux/atm.h>
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#include <linux/atmdev.h>
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#include <linux/capability.h>
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#include <linux/ppp_defs.h>
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#include <linux/if_ppp.h>
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#include <linux/ppp_channel.h>
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#include <linux/atmppp.h>
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#include "common.h"
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#if 0
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#define DPRINTK(format, args...) \
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printk(KERN_DEBUG "pppoatm: " format, ##args)
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#else
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#define DPRINTK(format, args...)
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#endif
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enum pppoatm_encaps {
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e_autodetect = PPPOATM_ENCAPS_AUTODETECT,
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e_vc = PPPOATM_ENCAPS_VC,
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e_llc = PPPOATM_ENCAPS_LLC,
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};
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struct pppoatm_vcc {
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struct atm_vcc *atmvcc; /* VCC descriptor */
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void (*old_push)(struct atm_vcc *, struct sk_buff *);
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void (*old_pop)(struct atm_vcc *, struct sk_buff *);
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/* keep old push/pop for detaching */
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enum pppoatm_encaps encaps;
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int flags; /* SC_COMP_PROT - compress protocol */
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struct ppp_channel chan; /* interface to generic ppp layer */
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struct tasklet_struct wakeup_tasklet;
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};
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/*
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* Header used for LLC Encapsulated PPP (4 bytes) followed by the LCP protocol
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* ID (0xC021) used in autodetection
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*/
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static const unsigned char pppllc[6] = { 0xFE, 0xFE, 0x03, 0xCF, 0xC0, 0x21 };
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#define LLC_LEN (4)
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static inline struct pppoatm_vcc *atmvcc_to_pvcc(const struct atm_vcc *atmvcc)
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{
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return (struct pppoatm_vcc *) (atmvcc->user_back);
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}
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static inline struct pppoatm_vcc *chan_to_pvcc(const struct ppp_channel *chan)
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{
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return (struct pppoatm_vcc *) (chan->private);
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}
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/*
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* We can't do this directly from our _pop handler, since the ppp code
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* doesn't want to be called in interrupt context, so we do it from
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* a tasklet
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*/
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static void pppoatm_wakeup_sender(unsigned long arg)
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{
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ppp_output_wakeup((struct ppp_channel *) arg);
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}
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/*
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* This gets called every time the ATM card has finished sending our
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* skb. The ->old_pop will take care up normal atm flow control,
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* but we also need to wake up the device if we blocked it
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*/
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static void pppoatm_pop(struct atm_vcc *atmvcc, struct sk_buff *skb)
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{
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struct pppoatm_vcc *pvcc = atmvcc_to_pvcc(atmvcc);
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pvcc->old_pop(atmvcc, skb);
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/*
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* We don't really always want to do this since it's
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* really inefficient - it would be much better if we could
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* test if we had actually throttled the generic layer.
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* Unfortunately then there would be a nasty SMP race where
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* we could clear that flag just as we refuse another packet.
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* For now we do the safe thing.
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*/
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tasklet_schedule(&pvcc->wakeup_tasklet);
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}
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/*
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* Unbind from PPP - currently we only do this when closing the socket,
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* but we could put this into an ioctl if need be
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*/
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static void pppoatm_unassign_vcc(struct atm_vcc *atmvcc)
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{
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struct pppoatm_vcc *pvcc;
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pvcc = atmvcc_to_pvcc(atmvcc);
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atmvcc->push = pvcc->old_push;
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atmvcc->pop = pvcc->old_pop;
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tasklet_kill(&pvcc->wakeup_tasklet);
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ppp_unregister_channel(&pvcc->chan);
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atmvcc->user_back = NULL;
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kfree(pvcc);
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/* Gee, I hope we have the big kernel lock here... */
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module_put(THIS_MODULE);
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}
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/* Called when an AAL5 PDU comes in */
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static void pppoatm_push(struct atm_vcc *atmvcc, struct sk_buff *skb)
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{
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struct pppoatm_vcc *pvcc = atmvcc_to_pvcc(atmvcc);
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DPRINTK("pppoatm push\n");
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if (skb == NULL) { /* VCC was closed */
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DPRINTK("removing ATMPPP VCC %p\n", pvcc);
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pppoatm_unassign_vcc(atmvcc);
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atmvcc->push(atmvcc, NULL); /* Pass along bad news */
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return;
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}
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atm_return(atmvcc, skb->truesize);
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switch (pvcc->encaps) {
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case e_llc:
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if (skb->len < LLC_LEN ||
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memcmp(skb->data, pppllc, LLC_LEN))
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goto error;
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skb_pull(skb, LLC_LEN);
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break;
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case e_autodetect:
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if (pvcc->chan.ppp == NULL) { /* Not bound yet! */
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kfree_skb(skb);
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return;
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}
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if (skb->len >= sizeof(pppllc) &&
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!memcmp(skb->data, pppllc, sizeof(pppllc))) {
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pvcc->encaps = e_llc;
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skb_pull(skb, LLC_LEN);
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break;
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}
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if (skb->len >= (sizeof(pppllc) - LLC_LEN) &&
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!memcmp(skb->data, &pppllc[LLC_LEN],
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sizeof(pppllc) - LLC_LEN)) {
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pvcc->encaps = e_vc;
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pvcc->chan.mtu += LLC_LEN;
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break;
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}
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DPRINTK("(unit %d): Couldn't autodetect yet "
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"(skb: %02X %02X %02X %02X %02X %02X)\n",
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pvcc->chan.unit,
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skb->data[0], skb->data[1], skb->data[2],
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skb->data[3], skb->data[4], skb->data[5]);
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goto error;
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case e_vc:
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break;
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}
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ppp_input(&pvcc->chan, skb);
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return;
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error:
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kfree_skb(skb);
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ppp_input_error(&pvcc->chan, 0);
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}
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/*
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* Called by the ppp_generic.c to send a packet - returns true if packet
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* was accepted. If we return false, then it's our job to call
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* ppp_output_wakeup(chan) when we're feeling more up to it.
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* Note that in the ENOMEM case (as opposed to the !atm_may_send case)
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* we should really drop the packet, but the generic layer doesn't
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* support this yet. We just return 'DROP_PACKET' which we actually define
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* as success, just to be clear what we're really doing.
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*/
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#define DROP_PACKET 1
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static int pppoatm_send(struct ppp_channel *chan, struct sk_buff *skb)
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{
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struct pppoatm_vcc *pvcc = chan_to_pvcc(chan);
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ATM_SKB(skb)->vcc = pvcc->atmvcc;
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DPRINTK("(unit %d): pppoatm_send (skb=0x%p, vcc=0x%p)\n",
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pvcc->chan.unit, skb, pvcc->atmvcc);
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if (skb->data[0] == '\0' && (pvcc->flags & SC_COMP_PROT))
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(void) skb_pull(skb, 1);
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switch (pvcc->encaps) { /* LLC encapsulation needed */
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case e_llc:
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if (skb_headroom(skb) < LLC_LEN) {
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struct sk_buff *n;
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n = skb_realloc_headroom(skb, LLC_LEN);
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if (n != NULL &&
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!atm_may_send(pvcc->atmvcc, n->truesize)) {
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kfree_skb(n);
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goto nospace;
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}
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kfree_skb(skb);
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if ((skb = n) == NULL)
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return DROP_PACKET;
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} else if (!atm_may_send(pvcc->atmvcc, skb->truesize))
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goto nospace;
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memcpy(skb_push(skb, LLC_LEN), pppllc, LLC_LEN);
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break;
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case e_vc:
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if (!atm_may_send(pvcc->atmvcc, skb->truesize))
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goto nospace;
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break;
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case e_autodetect:
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DPRINTK("(unit %d): Trying to send without setting encaps!\n",
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pvcc->chan.unit);
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kfree_skb(skb);
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return 1;
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}
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atomic_add(skb->truesize, &sk_atm(ATM_SKB(skb)->vcc)->sk_wmem_alloc);
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ATM_SKB(skb)->atm_options = ATM_SKB(skb)->vcc->atm_options;
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DPRINTK("(unit %d): atm_skb(%p)->vcc(%p)->dev(%p)\n",
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pvcc->chan.unit, skb, ATM_SKB(skb)->vcc,
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ATM_SKB(skb)->vcc->dev);
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return ATM_SKB(skb)->vcc->send(ATM_SKB(skb)->vcc, skb)
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? DROP_PACKET : 1;
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nospace:
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/*
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* We don't have space to send this SKB now, but we might have
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* already applied SC_COMP_PROT compression, so may need to undo
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*/
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if ((pvcc->flags & SC_COMP_PROT) && skb_headroom(skb) > 0 &&
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skb->data[-1] == '\0')
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(void) skb_push(skb, 1);
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return 0;
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}
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/* This handles ioctls sent to the /dev/ppp interface */
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static int pppoatm_devppp_ioctl(struct ppp_channel *chan, unsigned int cmd,
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unsigned long arg)
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{
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switch (cmd) {
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case PPPIOCGFLAGS:
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return put_user(chan_to_pvcc(chan)->flags, (int __user *) arg)
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? -EFAULT : 0;
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case PPPIOCSFLAGS:
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return get_user(chan_to_pvcc(chan)->flags, (int __user *) arg)
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? -EFAULT : 0;
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}
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return -ENOTTY;
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}
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static /*const*/ struct ppp_channel_ops pppoatm_ops = {
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.start_xmit = pppoatm_send,
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.ioctl = pppoatm_devppp_ioctl,
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};
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static int pppoatm_assign_vcc(struct atm_vcc *atmvcc, void __user *arg)
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{
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struct atm_backend_ppp be;
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struct pppoatm_vcc *pvcc;
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int err;
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/*
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* Each PPPoATM instance has its own tasklet - this is just a
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* prototypical one used to initialize them
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*/
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static const DECLARE_TASKLET(tasklet_proto, pppoatm_wakeup_sender, 0);
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if (copy_from_user(&be, arg, sizeof be))
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return -EFAULT;
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if (be.encaps != PPPOATM_ENCAPS_AUTODETECT &&
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be.encaps != PPPOATM_ENCAPS_VC && be.encaps != PPPOATM_ENCAPS_LLC)
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return -EINVAL;
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pvcc = kmalloc(sizeof(*pvcc), GFP_KERNEL);
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if (pvcc == NULL)
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return -ENOMEM;
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memset(pvcc, 0, sizeof(*pvcc));
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pvcc->atmvcc = atmvcc;
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pvcc->old_push = atmvcc->push;
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pvcc->old_pop = atmvcc->pop;
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pvcc->encaps = (enum pppoatm_encaps) be.encaps;
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pvcc->chan.private = pvcc;
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pvcc->chan.ops = &pppoatm_ops;
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pvcc->chan.mtu = atmvcc->qos.txtp.max_sdu - PPP_HDRLEN -
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(be.encaps == e_vc ? 0 : LLC_LEN);
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pvcc->wakeup_tasklet = tasklet_proto;
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pvcc->wakeup_tasklet.data = (unsigned long) &pvcc->chan;
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if ((err = ppp_register_channel(&pvcc->chan)) != 0) {
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kfree(pvcc);
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return err;
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}
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atmvcc->user_back = pvcc;
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atmvcc->push = pppoatm_push;
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atmvcc->pop = pppoatm_pop;
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__module_get(THIS_MODULE);
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return 0;
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}
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/*
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* This handles ioctls actually performed on our vcc - we must return
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* -ENOIOCTLCMD for any unrecognized ioctl
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*/
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static int pppoatm_ioctl(struct socket *sock, unsigned int cmd,
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unsigned long arg)
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{
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struct atm_vcc *atmvcc = ATM_SD(sock);
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void __user *argp = (void __user *)arg;
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if (cmd != ATM_SETBACKEND && atmvcc->push != pppoatm_push)
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return -ENOIOCTLCMD;
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switch (cmd) {
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case ATM_SETBACKEND: {
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atm_backend_t b;
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if (get_user(b, (atm_backend_t __user *) argp))
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return -EFAULT;
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if (b != ATM_BACKEND_PPP)
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return -ENOIOCTLCMD;
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if (!capable(CAP_NET_ADMIN))
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return -EPERM;
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return pppoatm_assign_vcc(atmvcc, argp);
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}
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case PPPIOCGCHAN:
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return put_user(ppp_channel_index(&atmvcc_to_pvcc(atmvcc)->
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chan), (int __user *) argp) ? -EFAULT : 0;
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case PPPIOCGUNIT:
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return put_user(ppp_unit_number(&atmvcc_to_pvcc(atmvcc)->
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chan), (int __user *) argp) ? -EFAULT : 0;
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}
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return -ENOIOCTLCMD;
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}
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static struct atm_ioctl pppoatm_ioctl_ops = {
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.owner = THIS_MODULE,
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.ioctl = pppoatm_ioctl,
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};
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static int __init pppoatm_init(void)
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{
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register_atm_ioctl(&pppoatm_ioctl_ops);
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return 0;
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}
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static void __exit pppoatm_exit(void)
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{
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deregister_atm_ioctl(&pppoatm_ioctl_ops);
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}
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module_init(pppoatm_init);
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module_exit(pppoatm_exit);
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MODULE_AUTHOR("Mitchell Blank Jr <mitch@sfgoth.com>");
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MODULE_DESCRIPTION("RFC2364 PPP over ATM/AAL5");
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MODULE_LICENSE("GPL");
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