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simpler ptr loop check.

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git-svn-id: file:///svn/unbound/trunk@984 be551aaa-1e26-0410-a405-d3ace91eadb9
This commit is contained in:
Wouter Wijngaards 2008-02-22 11:19:21 +00:00
parent fb1bdb8ee0
commit fa368eff78
2 changed files with 6 additions and 19 deletions
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2
doc/Changelog
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@ -5,6 +5,8 @@
profile reports. profile reports.
- default is now minievent - not libevent. As its faster and - default is now minievent - not libevent. As its faster and
not needed for regular installs, only for very large port ranges. not needed for regular installs, only for very large port ranges.
- loop check different speedup pkt-dname-reading, 1% faster for
nocache-recursion check.
21 February 2008: Wouter 21 February 2008: Wouter
- speedup of root-delegation message encoding by 15%. - speedup of root-delegation message encoding by 15%.

23
util/data/dname.c
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@ -145,34 +145,19 @@ query_dname_tolower(uint8_t* dname)
/** maximum compression pointer position pointed to */ /** maximum compression pointer position pointed to */
#define MAX_COMPRESS_POS 16384 #define MAX_COMPRESS_POS 16384
/** size of bitmap for loop detection */ /** max number of compression ptrs to follow */
#define LOOP_BITMAP_SIZE (MAX_COMPRESS_POS/8) #define MAX_COMPRESS_PTRS 256
/** check bit in bitmap for loop detection, then set it for next check */
static uint8_t
loopcheck(uint8_t loop[], size_t pos)
{
const uint8_t bits[8] = {0x1, 0x2, 0x4, 0x8, 0x10, 0x20, 0x40, 0x80};
uint8_t ret;
log_assert(pos < MAX_COMPRESS_POS);
ret = loop[ pos / 8 ] & bits[ pos & 0x7 ];
loop[ pos / 8 ] |= bits[ pos & 0x7 ];
return ret;
}
size_t size_t
pkt_dname_len(ldns_buffer* pkt) pkt_dname_len(ldns_buffer* pkt)
{ {
size_t len = 0; size_t len = 0;
uint8_t loop[LOOP_BITMAP_SIZE]; /* loopcheck array. */ int ptrcount = 0;
uint8_t labellen; uint8_t labellen;
size_t endpos = 0; size_t endpos = 0;
/* read dname and determine length */ /* read dname and determine length */
/* check compression pointers, loops, out of bounds */ /* check compression pointers, loops, out of bounds */
memset(loop, 0, sizeof(loop));
while(1) { while(1) {
/* read next label */ /* read next label */
if(ldns_buffer_remaining(pkt) < 1) if(ldns_buffer_remaining(pkt) < 1)
@ -184,7 +169,7 @@ pkt_dname_len(ldns_buffer* pkt)
if(ldns_buffer_remaining(pkt) < 1) if(ldns_buffer_remaining(pkt) < 1)
return 0; return 0;
ptr = PTR_OFFSET(labellen, ldns_buffer_read_u8(pkt)); ptr = PTR_OFFSET(labellen, ldns_buffer_read_u8(pkt));
if(loopcheck(loop, ptr)) if(ptrcount++ > MAX_COMPRESS_PTRS)
return 0; /* loop! */ return 0; /* loop! */
if(ldns_buffer_limit(pkt) <= ptr) if(ldns_buffer_limit(pkt) <= ptr)
return 0; /* out of bounds! */ return 0; /* out of bounds! */