linux/mppe/linux-2.2.20-pad.patch

   1 --- linux/drivers/net/ppp.c.orig        Sun Mar 25 08:31:15 2001
   2 +++ linux/drivers/net/ppp.c     Mon Mar 25 09:27:28 2002
   3 @@ -2468,10 +2468,14 @@
   4             (proto != PPP_LCP)                  &&
   5             (proto != PPP_CCP)) {
   6                 struct sk_buff *new_skb;
   7 +               int new_skb_size = ppp->mtu + PPP_HDRLEN;
   8                 int new_count;
   9
  10                 /* Allocate an skb for the compressed frame. */
  11 -               new_skb = alloc_skb(ppp->mtu + PPP_HDRLEN, GFP_ATOMIC);
  12 +               if (ppp->sc_xcomp->compress_proto == CI_MPPE)
  13 +                       /* CCP [must have] reduced MTU by MPPE_PAD. */
  14 +                       new_skb_size += MPPE_PAD;
  15 +               new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
  16                 if (new_skb == NULL) {
  17                         printk(KERN_ERR "ppp_send_frame: no memory\n");
  18                         kfree_skb(skb);
  19 @@ -2482,19 +2486,32 @@
  20                 /* Compress the frame. */
  21                 new_count = (*ppp->sc_xcomp->compress)
  22                         (ppp->sc_xc_state, data, new_skb->data,
  23 -                        count, ppp->mtu + PPP_HDRLEN);
  24 +                        count, new_skb_size);
  25
  26                 /* Did it compress? */
  27                 if (new_count > 0 && (ppp->flags & SC_CCP_UP)) {
  28                         skb_put(new_skb, new_count);
  29                         kfree_skb(skb);
  30                         skb = new_skb;
  31 -               } else {
  32 +               } else if (new_count == 0) {
  33                         /*
  34                          * The frame could not be compressed, or it could not
  35                          * be sent in compressed form because CCP is down.
  36                          */
  37                         kfree_skb(new_skb);
  38 +               } else {
  39 +                       /*
  40 +                        * (new_count < 0)
  41 +                        * MPPE requires that we do not send unencrypted
  42 +                        * frames.  The compressor will return -1 if we
  43 +                        * should drop the frame.  We cannot simply test
  44 +                        * the compress_proto because MPPE and MPPC share
  45 +                        * the same number.
  46 +                        */
  47 +                       printk(KERN_ERR "ppp: compressor dropped pkt\n");
  48 +                       kfree_skb(new_skb);
  49 +                       ppp->xmit_busy = 0;
  50 +                       return;
  51                 }
  52         }
  53