On Fri, Sep 16, 2016 at 10:40:47AM -0300, Marcelo Ricardo Leitner wrote:
> On Fri, Sep 16, 2016 at 01:33:47PM +0000, David Laight wrote:
> > > > -static inline int ADDIP_SERIAL_gte(__u16 s, __u16 t)
> > > > +static inline int ADDIP_SERIAL_gte(__u32 s, __u32 t)
> > > > {
> > > > return ((s) == (t)) || (((t) - (s)) & ADDIP_SERIAL_SIGN_BIT);
> > > > }
> >
> > Does gcc manage to compile that to (s32)((t) - (s)) <= 0 ?
>
> I have no idea but I have a patch in the works for updating it to this
> form, to be more like time_after(). Will probably post it by next week.
Just for reference, this should be it. Not realy tested yet.
commit b52575533dfefa1908c7bbe35bde0fa8359dd1a3
Author: Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>
Date: Tue Aug 9 14:45:35 2016 -0300
sctp: improve how SSN, TSN and ASCONF serial are compared
Make it similar to time_before() macros instead.
This patch also removes SSN_lte as it is not used.
diff --git a/include/net/sctp/sm.h b/include/net/sctp/sm.h
index bafe2a0ab908..d30cfb6d0480 100644
--- a/include/net/sctp/sm.h
+++ b/include/net/sctp/sm.h
@@ -335,19 +335,15 @@ static inline __u16 sctp_data_size(struct sctp_chunk *chunk)
* Number Arithmetic as defined in [RFC1982] where SERIAL_BITS = 32.
*/
-enum {
- TSN_SIGN_BIT = (1<<31)
-};
+#define TSN_lt(a,b) \
+ (typecheck(__u32, a) && \
+ typecheck(__u32, b) && \
+ ((__s32)((a) - (b)) < 0))
-static inline int TSN_lt(__u32 s, __u32 t)
-{
- return ((s) - (t)) & TSN_SIGN_BIT;
-}
-
-static inline int TSN_lte(__u32 s, __u32 t)
-{
- return ((s) == (t)) || (((s) - (t)) & TSN_SIGN_BIT);
-}
+#define TSN_lte(a,b) \
+ (typecheck(__u32, a) && \
+ typecheck(__u32, b) && \
+ ((__s32)((a) - (b)) <= 0))
/* Compare two SSNs */
@@ -356,36 +352,22 @@ static inline int TSN_lte(__u32 s, __u32 t)
* 1.6 Serial Number Arithmetic
*
* Comparisons and arithmetic on Stream Sequence Numbers in this document
- * SHOULD use Serial Number Arithmetic as defined in [RFC1982] where
- * SERIAL_BITS = 16.
+ * SHOULD use Serial Number Arithmetic as defined in [RFC1982]
*/
-enum {
- SSN_SIGN_BIT = (1<<15)
-};
-
-static inline int SSN_lt(__u16 s, __u16 t)
-{
- return ((s) - (t)) & SSN_SIGN_BIT;
-}
-
-static inline int SSN_lte(__u16 s, __u16 t)
-{
- return ((s) == (t)) || (((s) - (t)) & SSN_SIGN_BIT);
-}
+#define SSN_lt(a,b) \
+ (typecheck(__u16, a) && \
+ typecheck(__u16, b) && \
+ ((__s16)((a) - (b)) < 0))
/*
* ADDIP 3.1.1
* The valid range of Serial Number is from 0 to 4294967295 (2**32 - 1). Serial
* Numbers wrap back to 0 after reaching 4294967295.
*/
-enum {
- ADDIP_SERIAL_SIGN_BIT = (1<<31)
-};
-
-static inline int ADDIP_SERIAL_gte(__u32 s, __u32 t)
-{
- return ((s) == (t)) || (((t) - (s)) & ADDIP_SERIAL_SIGN_BIT);
-}
+#define ADDIP_SERIAL_gte(a,b) \
+ (typecheck(__u32, a) && \
+ typecheck(__u32, b) && \
+ ((__s32)((b) - (a)) <= 0))
/* Check VTAG of the packet matches the sender's own tag. */
static inline int
diff --git a/net/sctp/outqueue.c b/net/sctp/outqueue.c
index 72e54a416af6..6612d52599ae 100644
--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -1747,7 +1747,7 @@ static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn)
{
int i;
sctp_sack_variable_t *frags;
- __u16 gap;
+ __u16 gap, blocks;
__u32 ctsn = ntohl(sack->cum_tsn_ack);
if (TSN_lte(tsn, ctsn))
@@ -1767,9 +1767,10 @@ static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn)
frags = sack->variable;
gap = tsn - ctsn;
- for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) {
- if (TSN_lte(ntohs(frags[i].gab.start), gap) &&
- TSN_lte(gap, ntohs(frags[i].gab.end)))
+ blocks = ntohs(sack->num_gap_ack_blocks);
+ for (i = 0; i < blocks; ++i) {
+ if (TSN_lte((__u32)ntohs(frags[i].gab.start), (__u32)gap) &&
+ TSN_lte((__u32)gap, (__u32)ntohs(frags[i].gab.end)))
goto pass;
}
--
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