[PATCH ppp-2.4.3] add SC_MUST_COMP flag

[Matt Domsch <Matt_Domsch-8PEkshWhKlo@public.gmane.org>]

(rediff with license on include/linux/if_ppp.h untouched, and I had
named the new flag SC_MUST_COMP not SC_MUST_COMPRESS)

PPP 2.4.3 patch creates the new flag SC_MUST_COMP.  This is set on
CCP UP with MPPE enabled, and never cleared.  The kernel uses this
flag to drop packets which aren't compressed/decompressed properly
when MPPE is enabled.
 
In the existing code, on SIGUSR2, CCP is renegotiated, and with MPPE
enabled, LCP (and thus the link) is taken down, so the user can't
disable MPPE after it's enabled on a link.


1) sync to kernel's include/linux/if_ppp.h copy, adding
   SC_MUST_COMP
2) add SC_MUST_COMP to include/net/if_ppp.h also
3) set SC_MUST_COMP on CCP UP

 include/linux/if_ppp.h |    5 +++--
 include/net/if_ppp.h   |    1
 pppd/ccp.c             |   15 +++++++----
 pppd/pppd.h            |    2 -
 pppd/sys-linux.c       |    6 +++-
 pppd/sys-solaris.c     |    4 +--
 6 files changed, 21 insertions(+), 12 deletions(-)


Lightly tested, review much appeciated.

Signed-off-by: Matt Domsch <Matt_Domsch-8PEkshWhKlo@public.gmane.org>

-- 
Matt Domsch
Software Architect
Dell Linux Solutions linux.dell.com & www.dell.com/linux
Linux on Dell mailing lists @ http://lists.us.dell.com

diff -urNp --exclude-from=/mdomsch2/excludes --minimal ppp-2.4.3.orig/include/linux/if_ppp.h ppp-2.4.3.ppp_mppe/include/linux/if_ppp.h
--- ppp-2.4.3.orig/include/linux/if_ppp.h	2002-12-06 01:49:15.000000000 -0800
+++ ppp-2.4.3.ppp_mppe/include/linux/if_ppp.h	2005-08-14 09:59:40.000000000 -0700
@@ -44,7 +44,7 @@
  */
 
 /*
- *  ==FILEVERSION 20000724==
+ *  ==FILEVERSION 20050812==
  *
  *  NOTE TO MAINTAINERS:
  *     If you modify this file at all, please set the above date.
@@ -93,7 +93,8 @@
 #define SC_LOG_RAWIN	0x00080000	/* log all chars received */
 #define SC_LOG_FLUSH	0x00100000	/* log all chars flushed */
 #define	SC_SYNC		0x00200000	/* synchronous serial mode */
-#define	SC_MASK		0x0f200fff	/* bits that user can change */
+#define	SC_MUST_COMP    0x00400000	/* no uncompressed packets may be sent or received */
+#define	SC_MASK		0x0f600fff	/* bits that user can change */
 
 /* state bits */
 #define SC_XMIT_BUSY	0x10000000	/* (used by isdn_ppp?) */
diff -urNp --exclude-from=/mdomsch2/excludes --minimal ppp-2.4.3.orig/include/net/if_ppp.h ppp-2.4.3.ppp_mppe/include/net/if_ppp.h
--- ppp-2.4.3.orig/include/net/if_ppp.h	2002-12-06 01:49:15.000000000 -0800
+++ ppp-2.4.3.ppp_mppe/include/net/if_ppp.h	2005-08-13 20:08:55.000000000 -0700
@@ -66,6 +66,7 @@
 #define SC_RCV_EVNP	0x04000000	/* have rcvd char with even parity */
 #define SC_RCV_ODDP	0x08000000	/* have rcvd char with odd parity */
 #define SC_SYNC		0x00200000	/* use synchronous HDLC framing */
+#define	SC_MUST_COMP    0x00400000	/* no uncompressed packets may be sent or received */
 #define	SC_MASK		0x0fff00ff	/* bits that user can change */
 
 /*
diff -urNp --exclude-from=/mdomsch2/excludes --minimal ppp-2.4.3.orig/pppd/ccp.c ppp-2.4.3.ppp_mppe/pppd/ccp.c
--- ppp-2.4.3.orig/pppd/ccp.c	2004-11-12 18:28:15.000000000 -0800
+++ ppp-2.4.3.ppp_mppe/pppd/ccp.c	2005-08-12 11:53:31.000000000 -0700
@@ -390,7 +390,7 @@ ccp_open(unit)
     fsm *f = &ccp_fsm[unit];
 
     if (f->state != OPENED)
-	ccp_flags_set(unit, 1, 0);
+	ccp_flags_set(unit, 1, 0, 0);
 
     /*
      * Find out which compressors the kernel supports before
@@ -411,7 +411,7 @@ ccp_close(unit, reason)
     int unit;
     char *reason;
 {
-    ccp_flags_set(unit, 0, 0);
+    ccp_flags_set(unit, 0, 0, 0);
     fsm_close(&ccp_fsm[unit], reason);
 }
 
@@ -511,7 +511,7 @@ static void
 ccp_protrej(unit)
     int unit;
 {
-    ccp_flags_set(unit, 0, 0);
+    ccp_flags_set(unit, 0, 0, 0);
     fsm_lowerdown(&ccp_fsm[unit]);
 
 #ifdef MPPE
@@ -1424,8 +1424,13 @@ ccp_up(f)
     ccp_options *go = &ccp_gotoptions[f->unit];
     ccp_options *ho = &ccp_hisoptions[f->unit];
     char method1[64];
+    int must_comp = 0;
 
-    ccp_flags_set(f->unit, 1, 1);
+#ifdef MPPE
+    if (go->mppe)
+	    must_comp = 1;
+#endif
+    ccp_flags_set(f->unit, 1, 1, must_comp);
     if (ANY_COMPRESS(*go)) {
 	if (ANY_COMPRESS(*ho)) {
 	    if (go->method == ho->method) {
@@ -1458,7 +1463,7 @@ ccp_down(f)
     if (ccp_localstate[f->unit] & RACK_PENDING)
 	UNTIMEOUT(ccp_rack_timeout, f);
     ccp_localstate[f->unit] = 0;
-    ccp_flags_set(f->unit, 1, 0);
+    ccp_flags_set(f->unit, 1, 0, 0);
 #ifdef MPPE
     if (ccp_gotoptions[f->unit].mppe) {
 	ccp_gotoptions[f->unit].mppe = 0;
diff -urNp --exclude-from=/mdomsch2/excludes --minimal ppp-2.4.3.orig/pppd/pppd.h ppp-2.4.3.ppp_mppe/pppd/pppd.h
--- ppp-2.4.3.orig/pppd/pppd.h	2004-11-13 04:02:22.000000000 -0800
+++ ppp-2.4.3.ppp_mppe/pppd/pppd.h	2005-08-12 11:40:40.000000000 -0700
@@ -615,7 +615,7 @@ void tty_recv_config __P((int, u_int32_t
 				/* Configure i/f receive parameters */
 int  ccp_test __P((int, u_char *, int, int));
 				/* Test support for compression scheme */
-void ccp_flags_set __P((int, int, int));
+void ccp_flags_set __P((int, int, int, int));
 				/* Set kernel CCP state */
 int  ccp_fatal_error __P((int)); /* Test for fatal decomp error in kernel */
 int  get_idle_time __P((int, struct ppp_idle *));
diff -urNp --exclude-from=/mdomsch2/excludes --minimal ppp-2.4.3.orig/pppd/sys-linux.c ppp-2.4.3.ppp_mppe/pppd/sys-linux.c
--- ppp-2.4.3.orig/pppd/sys-linux.c	2005-07-23 08:35:09.000000000 -0700
+++ ppp-2.4.3.ppp_mppe/pppd/sys-linux.c	2005-08-12 11:37:39.000000000 -0700
@@ -1278,13 +1278,15 @@ ccp_test(int unit, u_char *opt_ptr, int 
 /********************************************************************
  *
  * ccp_flags_set - inform kernel about the current state of CCP.
+ *   Once SC_MUST_COMP is set, never clear it.
  */
 
-void ccp_flags_set (int unit, int isopen, int isup)
+void ccp_flags_set (int unit, int isopen, int isup, int must_comp)
 {
 	int x;
 
-	x = (isopen? SC_CCP_OPEN: 0) | (isup? SC_CCP_UP: 0);
+	x = (isopen? SC_CCP_OPEN: 0) | (isup? SC_CCP_UP: 0)
+		| (must_comp? SC_MUST_COMP: 0);
 	if (still_ppp() && ppp_dev_fd >= 0)
 		modify_flags(ppp_dev_fd, SC_CCP_OPEN|SC_CCP_UP, x);
 }
diff -urNp --exclude-from=/mdomsch2/excludes --minimal ppp-2.4.3.orig/pppd/sys-solaris.c ppp-2.4.3.ppp_mppe/pppd/sys-solaris.c
--- ppp-2.4.3.orig/pppd/sys-solaris.c	2004-11-04 02:02:26.000000000 -0800
+++ ppp-2.4.3.ppp_mppe/pppd/sys-solaris.c	2005-08-12 11:41:59.000000000 -0700
@@ -1633,8 +1633,8 @@ ccp_test(unit, opt_ptr, opt_len, for_tra
  * ccp_flags_set - inform kernel about the current state of CCP.
  */
 void
-ccp_flags_set(unit, isopen, isup)
-    int unit, isopen, isup;
+ccp_flags_set(unit, isopen, isup, unused_must_comp)
+    int unit, isopen, isup, unused_must_comp;
 {
     int cf[2];
 


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