proposed patch to iproute2-2.2.4-now-ss001007

[Werner Almesberger <Werner.Almesberger@epfl.ch>]

This patch changes the use of the default_index option of "tc qdisc dsmark"
as follows:

 - "default_index 0" is no longer treated like an absent default_index
   option, but tc tries to set the default index to 0 instead. If the
   kernel contains the patch I've sent this morning, this works.
   Otherwise (i.e. with an older kernel), we get EINVAL.
 - defaut_index arguments larger than 0xffff are no longer silently
   truncated, but you get an error instead

I don't think the second change is much of a problem. The first change
would break scripts that use "default_index 0" to explicitly request
that no default index be used. I think such usage is pretty uncommon,
and I'd take this small risk for the benefit of a consistent syntax.

Comments ?

- Werner

---------------------------------- cut here -----------------------------------

--- iproute2.orig/tc/q_dsmark.c	Sun Apr 16 19:42:54 2000
+++ iproute2/tc/q_dsmark.c	Thu Jan  4 14:51:53 2001
@@ -33,11 +33,12 @@
     struct nlmsghdr *n)
 {
 	struct rtattr *tail;
-	__u16 ind,dflt;
+	__u16 ind;
 	char *end;
-	int set_tc_index;
+	int set_tc_index,default_index;
 
-	ind = dflt = set_tc_index = 0;
+	ind = set_tc_index = 0;
+	default_index = -1;
 	while (argc > 0) {
 		if (!strcmp(*argv,"indices")) {
 			NEXT_ARG();
@@ -50,8 +51,9 @@
 		else if (!strcmp(*argv,"default_index") || !strcmp(*argv,
 		    "default")) {
 			NEXT_ARG();
-			dflt = strtoul(*argv,&end,0);
-			if (*end) {
+			default_index = strtol(*argv,&end,0);
+			if (*end || default_index < 0 ||
+			    default_index > 0xffff) {
 				explain();
 				return -1;
 			}
@@ -73,7 +75,11 @@
 	tail = (struct rtattr *) (((void *) n)+NLMSG_ALIGN(n->nlmsg_len));
 	addattr_l(n,1024,TCA_OPTIONS,NULL,0);
 	addattr_l(n,1024,TCA_DSMARK_INDICES,&ind,sizeof(ind));
-	if (dflt) addattr_l(n,1024,TCA_DSMARK_DEFAULT_INDEX,&dflt,sizeof(dflt));
+	if (default_index != -1) {
+		__u16 dflt = default_index;
+
+		addattr_l(n,1024,TCA_DSMARK_DEFAULT_INDEX,&dflt,sizeof(dflt));
+	}
 	if (set_tc_index) addattr_l(n,1024,TCA_DSMARK_SET_TC_INDEX,NULL,0);
 	tail->rta_len = (((void *) n)+n->nlmsg_len)-(void *) tail;
 	return 0;

-- 
  _________________________________________________________________________
 / Werner Almesberger, ICA, EPFL, CH           Werner.Almesberger@epfl.ch /
/_IN_N_032__Tel_+41_21_693_6621__Fax_+41_21_693_6610_____________________/