simpler ptr loop check.

git-svn-id: file:///svn/unbound/trunk@984 be551aaa-1e26-0410-a405-d3ace91eadb9

diff --git a/doc/Changelog b/doc/Changelog
index fd2c2cfccbbe71d4331f9edfbf21b7590f6c8976..634d55360ab027e5c1311e28dc7b4dc0370426f4 100644 (file)
--- a/doc/Changelog
+++ b/doc/Changelog
@@ -5,6 +5,8 @@
          profile reports.
        - default is now minievent - not libevent. As its faster and
          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
        - speedup of root-delegation message encoding by 15%.

diff --git a/util/data/dname.c b/util/data/dname.c
index a4d92688b210ee4d0e78847c43a1afc2e6309c43..4ba6c14acc2f95088ae22a2b59d05058341ab485 100644 (file)
--- a/util/data/dname.c
+++ b/util/data/dname.c
@@ -145,34 +145,19 @@ query_dname_tolower(uint8_t* dname)
 
 /** maximum compression pointer position pointed to */
 #define MAX_COMPRESS_POS 16384
-/** size of bitmap for loop detection */
-#define LOOP_BITMAP_SIZE (MAX_COMPRESS_POS/8)
-
-/** 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;
-}
-
+/** max number of compression ptrs to follow */
+#define MAX_COMPRESS_PTRS 256
 
 size_t
 pkt_dname_len(ldns_buffer* pkt)
 {
        size_t len = 0;
-       uint8_t loop[LOOP_BITMAP_SIZE]; /* loopcheck array. */
+       int ptrcount = 0;
        uint8_t labellen;
        size_t endpos = 0;
 
        /* read dname and determine length */
        /* check compression pointers, loops, out of bounds */
-       memset(loop, 0, sizeof(loop));
-
        while(1) {
                /* read next label */
                if(ldns_buffer_remaining(pkt) < 1)
@@ -184,7 +169,7 @@ pkt_dname_len(ldns_buffer* pkt)
                        if(ldns_buffer_remaining(pkt) < 1)
                                return 0;
                        ptr = PTR_OFFSET(labellen, ldns_buffer_read_u8(pkt));
-                       if(loopcheck(loop, ptr))
+                       if(ptrcount++ > MAX_COMPRESS_PTRS)
                                return 0; /* loop! */
                        if(ldns_buffer_limit(pkt) <= ptr)
                                return 0; /* out of bounds! */