modify ppp_generic patch to avoid an if() test and extra additions on

every pass through ppp_send_frame(); make a 2.4.19+ version of it;
improve mppeinstall.sh.

3 files changed, 218 insertions, 24 deletions

diff --git a/linux/mppe/linux-2.4.18-pad.patch b/linux/mppe/linux-2.4.18-pad.patch
index 01a56ff..40d8a7e 100644
--- a/linux/mppe/linux-2.4.18-pad.patch
+++ b/linux/mppe/linux-2.4.18-pad.patch
@@ -1,29 +1,50 @@
---- linux/drivers/net/ppp_generic.c.orig	Mon Feb 25 11:37:59 2002
-+++ linux/drivers/net/ppp_generic.c	Mon Mar 25 10:19:53 2002
-@@ -1006,8 +1006,15 @@
+--- linux-2.4.18/drivers/net/ppp_generic.c.orig	Mon May 12 01:36:31 2003
++++ linux-2.4.18/drivers/net/ppp_generic.c	Mon May 12 03:09:13 2003
+@@ -99,6 +99,7 @@
+ 	spinlock_t	rlock;		/* lock for receive side */
+ 	spinlock_t	wlock;		/* lock for transmit side */
+ 	int		mru;		/* max receive unit */
++	int		mru_alloc;	/* MAX(1500,MRU) for dev_alloc_skb() */
+ 	unsigned int	flags;		/* control bits */
+ 	unsigned int	xstate;		/* transmit state bits */
+ 	unsigned int	rstate;		/* receive state bits */
+@@ -126,6 +127,7 @@
+ 	struct sock_fprog pass_filter;	/* filter for packets to pass */
+ 	struct sock_fprog active_filter;/* filter for pkts to reset idle */
+ #endif /* CONFIG_PPP_FILTER */
++	int		comp_pad;	/* padding for compressor (MPPE) */
+ };
+ 
+ /*
+@@ -531,6 +533,10 @@
+ 		if (get_user(val, (int *) arg))
+ 			break;
+ 		ppp->mru = val;
++		if (ppp->mru > ppp->mru_alloc)
++		    ppp->mru_alloc = ppp->mru;
++		else if (ppp->mru < PPP_MRU)
++		    ppp->mru_alloc = PPP_MRU;	/* shrink to minimum */
+ 		err = 0;
+ 		break;
+ 
+@@ -1006,8 +1012,8 @@
  	/* try to do packet compression */
  	if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state != 0
  	    && proto != PPP_LCP && proto != PPP_CCP) {
 -		new_skb = alloc_skb(ppp->dev->mtu + ppp->dev->hard_header_len,
 -				    GFP_ATOMIC);
-+		int new_skb_size = ppp->dev->mtu + ppp->dev->hard_header_len;
-+		int compressor_skb_size = ppp->dev->mtu + PPP_HDRLEN;
-+
-+		if (ppp->xcomp->compress_proto == CI_MPPE) {
-+			/* CCP [must have] reduced MTU by MPPE_PAD. */
-+			new_skb_size += MPPE_PAD;
-+			compressor_skb_size += MPPE_PAD;
-+		}
-+		new_skb = alloc_skb(new_skb_size, GFP_ATOMIC);
++		new_skb = alloc_skb(ppp->dev->mtu + ppp->dev->hard_header_len
++				    + ppp->comp_pad, GFP_ATOMIC);
  		if (new_skb == 0) {
  			printk(KERN_ERR "PPP: no memory (comp pkt)\n");
  			goto drop;
-@@ -1019,15 +1026,27 @@
+@@ -1019,15 +1025,28 @@
  		/* compressor still expects A/C bytes in hdr */
  		len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
  					   new_skb->data, skb->len + 2,
 -					   ppp->dev->mtu + PPP_HDRLEN);
-+					   compressor_skb_size);
++					   ppp->dev->mtu + ppp->comp_pad
++					   + PPP_HDRLEN);
  		if (len > 0 && (ppp->flags & SC_CCP_UP)) {
  			kfree_skb(skb);
  			skb = new_skb;
@@ -48,12 +69,12 @@
  		}
  	}
  
-@@ -1515,14 +1534,14 @@
+@@ -1515,14 +1534,15 @@
  	int len;
  
  	if (proto == PPP_COMP) {
 -		ns = dev_alloc_skb(ppp->mru + PPP_HDRLEN);
-+		ns = dev_alloc_skb(ppp->mru + 128 + PPP_HDRLEN);
++		ns = dev_alloc_skb(ppp->mru_alloc + PPP_HDRLEN);
  		if (ns == 0) {
  			printk(KERN_ERR "ppp_decompress_frame: no memory\n");
  			goto err;
@@ -61,7 +82,37 @@
  		/* the decompressor still expects the A/C bytes in the hdr */
  		len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
 -				skb->len + 2, ns->data, ppp->mru + PPP_HDRLEN);
-+				skb->len + 2, ns->data, ppp->mru + 128 + PPP_HDRLEN);
++				skb->len + 2, ns->data,
++				ppp->mru_alloc + PPP_HDRLEN);
  		if (len < 0) {
  			/* Pass the compressed frame to pppd as an
  			   error indication. */
+@@ -1949,6 +1969,20 @@
+ 			ppp_xmit_unlock(ppp);
+ 			err = 0;
+ 		}
++		if (ccp_option[0] == CI_MPPE)
++			/*
++			 * pppd (userland) has reduced the MTU by MPPE_PAD,
++			 * to accomodate "compressor" growth.  We must
++			 * increase the space allocated for compressor
++			 * output in ppp_send_frame() accordingly.  Note
++			 * that from a purist's view, it may be more correct
++			 * to require multilink and fragment large packets,
++			 * but that seems inefficient compared to this
++			 * little trick.
++			 */
++			ppp->comp_pad = MPPE_PAD;
++		else
++			ppp->comp_pad = 0;
+ 
+ 	} else {
+ 		ppp_recv_lock(ppp);
+@@ -2229,6 +2263,7 @@
+ 
+ 	ppp->file.index = unit;
+ 	ppp->mru = PPP_MRU;
++	ppp->mru_alloc = PPP_MRU;
+ 	init_ppp_file(&ppp->file, INTERFACE);
+ 	ppp->file.hdrlen = PPP_HDRLEN - 2;	/* don't count proto bytes */
+ 	for (i = 0; i < NUM_NP; ++i)
diff --git a/linux/mppe/linux-2.4.19-pad.patch b/linux/mppe/linux-2.4.19-pad.patch
new file mode 100644
index 0000000..17f751c
--- /dev/null
+++ b/linux/mppe/linux-2.4.19-pad.patch
@@ -0,0 +1,118 @@
+--- linux-2.4.19/drivers/net/ppp_generic.c.orig	Mon May 12 01:36:31 2003
++++ linux-2.4.19/drivers/net/ppp_generic.c	Mon May 12 03:09:13 2003
+@@ -99,6 +99,7 @@
+ 	spinlock_t	rlock;		/* lock for receive side 58 */
+ 	spinlock_t	wlock;		/* lock for transmit side 5c */
+ 	int		mru;		/* max receive unit 60 */
++	int		mru_alloc;	/* MAX(1500,MRU) for dev_alloc_skb() */
+ 	unsigned int	flags;		/* control bits 64 */
+ 	unsigned int	xstate;		/* transmit state bits 68 */
+ 	unsigned int	rstate;		/* receive state bits 6c */
+@@ -126,6 +127,7 @@
+ 	struct sock_fprog pass_filter;	/* filter for packets to pass */
+ 	struct sock_fprog active_filter;/* filter for pkts to reset idle */
+ #endif /* CONFIG_PPP_FILTER */
++	int		comp_pad;	/* padding for compressor (MPPE) */
+ };
+ 
+ /*
+@@ -531,6 +533,10 @@
+ 		if (get_user(val, (int *) arg))
+ 			break;
+ 		ppp->mru = val;
++		if (ppp->mru > ppp->mru_alloc)
++		    ppp->mru_alloc = ppp->mru;
++		else if (ppp->mru < PPP_MRU)
++		    ppp->mru_alloc = PPP_MRU;	/* shrink to minimum */
+ 		err = 0;
+ 		break;
+ 
+@@ -1006,8 +1012,8 @@
+ 	/* try to do packet compression */
+ 	if ((ppp->xstate & SC_COMP_RUN) && ppp->xc_state != 0
+ 	    && proto != PPP_LCP && proto != PPP_CCP) {
+-		new_skb = alloc_skb(ppp->dev->mtu + ppp->dev->hard_header_len,
+-				    GFP_ATOMIC);
++		new_skb = alloc_skb(ppp->dev->mtu + ppp->dev->hard_header_len
++				    + ppp->comp_pad, GFP_ATOMIC);
+ 		if (new_skb == 0) {
+ 			printk(KERN_ERR "PPP: no memory (comp pkt)\n");
+ 			goto drop;
+@@ -1019,15 +1025,28 @@
+ 		/* compressor still expects A/C bytes in hdr */
+ 		len = ppp->xcomp->compress(ppp->xc_state, skb->data - 2,
+ 					   new_skb->data, skb->len + 2,
+-					   ppp->dev->mtu + PPP_HDRLEN);
++					   ppp->dev->mtu + ppp->comp_pad
++					   + PPP_HDRLEN);
+ 		if (len > 0 && (ppp->flags & SC_CCP_UP)) {
+ 			kfree_skb(skb);
+ 			skb = new_skb;
+ 			skb_put(skb, len);
+ 			skb_pull(skb, 2);	/* pull off A/C bytes */
+-		} else {
++		} else if (len == 0) {
+ 			/* didn't compress, or CCP not up yet */
+ 			kfree_skb(new_skb);
++		} else {
++			/*
++			 * (len < 0)
++			 * MPPE requires that we do not send unencrypted
++			 * frames.  The compressor will return -1 if we
++			 * should drop the frame.  We cannot simply test
++			 * the compress_proto because MPPE and MPPC share
++			 * the same number.
++			 */
++			printk(KERN_ERR "ppp: compressor dropped pkt\n");
++			kfree_skb(new_skb);
++			goto drop;
+ 		}
+ 	}
+ 
+@@ -1515,14 +1534,15 @@
+ 	int len;
+ 
+ 	if (proto == PPP_COMP) {
+-		ns = dev_alloc_skb(ppp->mru + PPP_HDRLEN);
++		ns = dev_alloc_skb(ppp->mru_alloc + PPP_HDRLEN);
+ 		if (ns == 0) {
+ 			printk(KERN_ERR "ppp_decompress_frame: no memory\n");
+ 			goto err;
+ 		}
+ 		/* the decompressor still expects the A/C bytes in the hdr */
+ 		len = ppp->rcomp->decompress(ppp->rc_state, skb->data - 2,
+-				skb->len + 2, ns->data, ppp->mru + PPP_HDRLEN);
++				skb->len + 2, ns->data,
++				ppp->mru_alloc + PPP_HDRLEN);
+ 		if (len < 0) {
+ 			/* Pass the compressed frame to pppd as an
+ 			   error indication. */
+@@ -1949,6 +1969,20 @@
+ 			ppp_xmit_unlock(ppp);
+ 			err = 0;
+ 		}
++		if (ccp_option[0] == CI_MPPE)
++			/*
++			 * pppd (userland) has reduced the MTU by MPPE_PAD,
++			 * to accomodate "compressor" growth.  We must
++			 * increase the space allocated for compressor
++			 * output in ppp_send_frame() accordingly.  Note
++			 * that from a purist's view, it may be more correct
++			 * to require multilink and fragment large packets,
++			 * but that seems inefficient compared to this
++			 * little trick.
++			 */
++			ppp->comp_pad = MPPE_PAD;
++		else
++			ppp->comp_pad = 0;
+ 
+ 	} else {
+ 		ppp_recv_lock(ppp);
+@@ -2229,6 +2263,7 @@
+ 
+ 	ppp->file.index = unit;
+ 	ppp->mru = PPP_MRU;
++	ppp->mru_alloc = PPP_MRU;
+ 	init_ppp_file(&ppp->file, INTERFACE);
+ 	ppp->file.hdrlen = PPP_HDRLEN - 2;	/* don't count proto bytes */
+ 	for (i = 0; i < NUM_NP; ++i)
diff --git a/linux/mppe/mppeinstall.sh b/linux/mppe/mppeinstall.sh
index 5a81ffd..6a1f945 100644
--- a/linux/mppe/mppeinstall.sh
+++ b/linux/mppe/mppeinstall.sh
@@ -1,23 +1,48 @@
 #!/bin/sh
 #
-# A quickie script to install MPPE into the 2.2.19+ or 2.4.18 kernel.
+# A quickie script to install MPPE into the 2.2.19+ or 2.4.18+ kernel.
 # Does no error checking!!!
 #
 
 mppe_files="sha1.[ch] arcfour.[ch] ppp_mppe_compress.c"
 
-[ $1 ] || exit 1
-[ -d "$1" ] || exit 1
+if [ -z "$1" -o ! -d "$1" ]; then
+    echo "Usage: $0 <linux-source-dir>" >&2
+    exit 1
+fi
 
-echo -n "Is this a 2.2 kernel or 2.4 kernel: "
-read ver
+# strip any trailing /
+set -- ${1%/}
+# strip leading /path/to/linux-
+ver=`echo "${1##*/}" | sed -e 's/linux-//'` # -e 's/\/$//'
+if ! expr "$ver" : 2.[24] >/dev/null ; then
+    echo "Unable to determine kernel version ($ver)" >&2
+    exit 1
+fi
+
+# build patch files list
+patchdir=`pwd`
+patchfiles=
+if expr $ver : 2.2 >/dev/null ; then
+    patchfiles=$patchdir/linux-2.2.*.patch
+elif expr $ver : 2.4 >/dev/null ; then
+    patchfiles=`echo $patchdir/linux-2.4.18-{include,make}.patch`
+    # need to differentiate a bit
+    rel=${ver##*.}
+    if [ $rel -gt 18 ] ; then
+	patchfiles="$patchfiles $patchdir/linux-2.4.19-pad.patch"
+    else
+	patchfiles="$patchfiles $patchdir/linux-2.4.18-pad.patch"
+    fi
+fi
+
+echo "Detected kernel version $ver"
 echo "I will now patch the kernel in directory $1"
 echo -n "Press ret to continue, CTRL-C to exit: "
 read
 
-patchdir=`pwd`
 pushd "$1" >/dev/null
-for patch in $patchdir/linux-$ver.*.patch; do
+for patch in $patchfiles; do
     patch -p1 < $patch
 done