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authorGerrit Renker <gerrit@erg.abdn.ac.uk>2008-06-11 06:19:10 -0400
committerGerrit Renker <gerrit@erg.abdn.ac.uk>2008-06-11 06:19:10 -0400
commit7deb0f851003287d7e259bf6b33548b144c0f2d5 (patch)
tree8ede694c4b6cd41224f7165d09d3f5935d889fd1 /net/dccp
parent1e8a287c79f64226541f5c44aa52d4698bb84cf5 (diff)
dccp ccid-3: X truncated due to type conversion
This fixes a bug in computing the inter-packet-interval t_ipi = s/X: scaled_div32(a, b) uses u32 for b, but in "scaled_div32(s, X)" the type of the sending rate `X' is u64. Since X is scaled by 2^6, this truncates rates greater than 2^26 Bps (~537 Mbps). Using full 64-bit division now. Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
Diffstat (limited to 'net/dccp')
-rw-r--r--net/dccp/ccids/lib/tfrc.h14
1 files changed, 6 insertions, 8 deletions
diff --git a/net/dccp/ccids/lib/tfrc.h b/net/dccp/ccids/lib/tfrc.h
index ddd8107b927f..ed9857527acf 100644
--- a/net/dccp/ccids/lib/tfrc.h
+++ b/net/dccp/ccids/lib/tfrc.h
@@ -15,7 +15,7 @@
15 * (at your option) any later version. 15 * (at your option) any later version.
16 */ 16 */
17#include <linux/types.h> 17#include <linux/types.h>
18#include <asm/div64.h> 18#include <linux/math64.h>
19#include "../../dccp.h" 19#include "../../dccp.h"
20/* internal includes that this module exports: */ 20/* internal includes that this module exports: */
21#include "loss_interval.h" 21#include "loss_interval.h"
@@ -29,21 +29,19 @@ extern int tfrc_debug;
29#endif 29#endif
30 30
31/* integer-arithmetic divisions of type (a * 1000000)/b */ 31/* integer-arithmetic divisions of type (a * 1000000)/b */
32static inline u64 scaled_div(u64 a, u32 b) 32static inline u64 scaled_div(u64 a, u64 b)
33{ 33{
34 BUG_ON(b==0); 34 BUG_ON(b==0);
35 a *= 1000000; 35 return div64_u64(a * 1000000, b);
36 do_div(a, b);
37 return a;
38} 36}
39 37
40static inline u32 scaled_div32(u64 a, u32 b) 38static inline u32 scaled_div32(u64 a, u64 b)
41{ 39{
42 u64 result = scaled_div(a, b); 40 u64 result = scaled_div(a, b);
43 41
44 if (result > UINT_MAX) { 42 if (result > UINT_MAX) {
45 DCCP_CRIT("Overflow: a(%llu)/b(%u) > ~0U", 43 DCCP_CRIT("Overflow: %llu/%llu > UINT_MAX",
46 (unsigned long long)a, b); 44 (unsigned long long)a, (unsigned long long)b);
47 return UINT_MAX; 45 return UINT_MAX;
48 } 46 }
49 return result; 47 return result;