Commit 88e4f759 authored by David S. Miller's avatar David S. Miller

Merge branch 'sctp-fix-gap-ack-blocks'

Marcelo Ricardo Leitner says:

====================
sctp: fix the handling of SACK Gap Ack blocks

sctp_acked() is using 32bit arithmetics on 16bits vars, via TSN_lte()
macros, which is weird and confusing.

Once the offset to ctsn is calculated, all wrapping is already handled
and thus to verify the Gap Ack blocks we can just use pure
less/big-or-equal than checks.

Also, rename gap variable to tsn_offset, so it's more meaningful, as
it doesn't point to any gap at all.

Even so, I don't think this discrepancy resulted in any practical bug.

This patch is a preparation for the next one, which will introduce
typecheck() for TSN_lte() macros and would cause a compile error here.
Suggested-by: default avatarDavid Laight <David.Laight@ACULAB.COM>
Reported-by: default avatarDavid Laight <David.Laight@ACULAB.COM>
Signed-off-by: default avatarMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
====================
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 21641c2e 182691d0
...@@ -307,85 +307,27 @@ static inline __u16 sctp_data_size(struct sctp_chunk *chunk) ...@@ -307,85 +307,27 @@ static inline __u16 sctp_data_size(struct sctp_chunk *chunk)
} }
/* Compare two TSNs */ /* Compare two TSNs */
#define TSN_lt(a,b) \
(typecheck(__u32, a) && \
typecheck(__u32, b) && \
((__s32)((a) - (b)) < 0))
/* RFC 1982 - Serial Number Arithmetic #define TSN_lte(a,b) \
* (typecheck(__u32, a) && \
* 2. Comparison typecheck(__u32, b) && \
* Then, s1 is said to be equal to s2 if and only if i1 is equal to i2, ((__s32)((a) - (b)) <= 0))
* in all other cases, s1 is not equal to s2.
*
* s1 is said to be less than s2 if, and only if, s1 is not equal to s2,
* and
*
* (i1 < i2 and i2 - i1 < 2^(SERIAL_BITS - 1)) or
* (i1 > i2 and i1 - i2 > 2^(SERIAL_BITS - 1))
*
* s1 is said to be greater than s2 if, and only if, s1 is not equal to
* s2, and
*
* (i1 < i2 and i2 - i1 > 2^(SERIAL_BITS - 1)) or
* (i1 > i2 and i1 - i2 < 2^(SERIAL_BITS - 1))
*/
/*
* RFC 2960
* 1.6 Serial Number Arithmetic
*
* Comparisons and arithmetic on TSNs in this document SHOULD use Serial
* Number Arithmetic as defined in [RFC1982] where SERIAL_BITS = 32.
*/
enum {
TSN_SIGN_BIT = (1<<31)
};
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);
}
/* Compare two SSNs */ /* Compare two SSNs */
#define SSN_lt(a,b) \
/* (typecheck(__u16, a) && \
* RFC 2960 typecheck(__u16, b) && \
* 1.6 Serial Number Arithmetic ((__s16)((a) - (b)) < 0))
*
* Comparisons and arithmetic on Stream Sequence Numbers in this document /* ADDIP 3.1.1 */
* SHOULD use Serial Number Arithmetic as defined in [RFC1982] where #define ADDIP_SERIAL_gte(a,b) \
* SERIAL_BITS = 16. (typecheck(__u32, a) && \
*/ typecheck(__u32, b) && \
enum { ((__s32)((b) - (a)) <= 0))
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);
}
/*
* 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);
}
/* Check VTAG of the packet matches the sender's own tag. */ /* Check VTAG of the packet matches the sender's own tag. */
static inline int static inline int
......
...@@ -1719,7 +1719,7 @@ static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn) ...@@ -1719,7 +1719,7 @@ static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn)
{ {
int i; int i;
sctp_sack_variable_t *frags; sctp_sack_variable_t *frags;
__u16 gap; __u16 tsn_offset, blocks;
__u32 ctsn = ntohl(sack->cum_tsn_ack); __u32 ctsn = ntohl(sack->cum_tsn_ack);
if (TSN_lte(tsn, ctsn)) if (TSN_lte(tsn, ctsn))
...@@ -1738,10 +1738,11 @@ static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn) ...@@ -1738,10 +1738,11 @@ static int sctp_acked(struct sctp_sackhdr *sack, __u32 tsn)
*/ */
frags = sack->variable; frags = sack->variable;
gap = tsn - ctsn; blocks = ntohs(sack->num_gap_ack_blocks);
for (i = 0; i < ntohs(sack->num_gap_ack_blocks); ++i) { tsn_offset = tsn - ctsn;
if (TSN_lte(ntohs(frags[i].gab.start), gap) && for (i = 0; i < blocks; ++i) {
TSN_lte(gap, ntohs(frags[i].gab.end))) if (tsn_offset >= ntohs(frags[i].gab.start) &&
tsn_offset <= ntohs(frags[i].gab.end))
goto pass; goto pass;
} }
......
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