package/network/services/dnsmasq/patches/0118-Optimise-sort_rrset-for-the-case-where-the-RR-type-n.patch

   1 From 8ebdc364afd886461d209284ad4c946ac65e6d2b Mon Sep 17 00:00:00 2001
   2 From: Simon Kelley <simon@thekelleys.org.uk>
   3 Date: Fri, 22 Jan 2021 18:50:43 +0000
   4 Subject: [PATCH 3/4] Optimise sort_rrset for the case where the RR type no
   5  canonicalisation.
   6
   7 Signed-off-by: Kevin Darbyshire-Bryant <ldir@darbyshire-bryant.me.uk>
   8 ---
   9  src/dnssec.c | 69 ++++++++++++++++++++++++++++++++++++----------------
  10  1 file changed, 48 insertions(+), 21 deletions(-)
  11
  12 --- a/src/dnssec.c
  13 +++ b/src/dnssec.c
  14 @@ -333,37 +333,64 @@ static int sort_rrset(struct dns_header
  15           if (!CHECK_LEN(header, state2.ip, plen, rdlen2))
  16             return rrsetidx; /* short packet */
  17           state2.end = state2.ip + rdlen2;
  18 -
  19 -         while (1)
  20 +
  21 +         /* If the RR has no names in it then canonicalisation
  22 +            is the identity function and we can compare
  23 +            the RRs directly. If not we compare the
  24 +            canonicalised RRs one byte at a time. */
  25 +         if (*rr_desc == (u16)-1)
  26             {
  27 -             int ok1, ok2;
  28 +             int rdmin = rdlen1 > rdlen2 ? rdlen2 : rdlen1;
  29 +             int cmp = memcmp(state1.ip, state2.ip, rdmin);
  30
  31 -             ok1 = get_rdata(header, plen, &state1);
  32 -             ok2 = get_rdata(header, plen, &state2);
  33 -
  34 -             if (!ok1 && !ok2)
  35 +             if (cmp > 0 || (cmp == 0 && rdlen1 > rdmin))
  36 +               {
  37 +                 unsigned char *tmp = rrset[i+1];
  38 +                 rrset[i+1] = rrset[i];
  39 +                 rrset[i] = tmp;
  40 +                 swap = 1;
  41 +               }
  42 +             else if (cmp == 0 && (rdlen1 == rdlen2))
  43                 {
  44                   /* Two RRs are equal, remove one copy. RFC 4034, para 6.3 */
  45                   for (j = i+1; j < rrsetidx-1; j++)
  46                     rrset[j] = rrset[j+1];
  47                   rrsetidx--;
  48                   i--;
  49 -                 break;
  50                 }
  51 -             else if (ok1 && (!ok2 || *state1.op > *state2.op))
  52 -               {
  53 -                 unsigned char *tmp = rrset[i+1];
  54 -                 rrset[i+1] = rrset[i];
  55 -                 rrset[i] = tmp;
  56 -                 swap = 1;
  57 -                 break;
  58 -               }
  59 -             else if (ok2 && (!ok1 || *state2.op > *state1.op))
  60 -               break;
  61 -
  62 -             /* arrive here when bytes are equal, go round the loop again
  63 -                and compare the next ones. */
  64             }
  65 +         else
  66 +           /* Comparing canonicalised RRs, byte-at-a-time. */
  67 +           while (1)
  68 +             {
  69 +               int ok1, ok2;
  70 +
  71 +               ok1 = get_rdata(header, plen, &state1);
  72 +               ok2 = get_rdata(header, plen, &state2);
  73 +
  74 +               if (!ok1 && !ok2)
  75 +                 {
  76 +                   /* Two RRs are equal, remove one copy. RFC 4034, para 6.3 */
  77 +                   for (j = i+1; j < rrsetidx-1; j++)
  78 +                     rrset[j] = rrset[j+1];
  79 +                   rrsetidx--;
  80 +                   i--;
  81 +                   break;
  82 +                 }
  83 +               else if (ok1 && (!ok2 || *state1.op > *state2.op))
  84 +                 {
  85 +                   unsigned char *tmp = rrset[i+1];
  86 +                   rrset[i+1] = rrset[i];
  87 +                   rrset[i] = tmp;
  88 +                   swap = 1;
  89 +                   break;
  90 +                 }
  91 +               else if (ok2 && (!ok1 || *state2.op > *state1.op))
  92 +                 break;
  93 +
  94 +               /* arrive here when bytes are equal, go round the loop again
  95 +                  and compare the next ones. */
  96 +             }
  97         }
  98      } while (swap);
  99