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Date: Sat, 10 Feb 2001 13:14:16 -0600
From: Greg Hewgill <greg@hewgill.com>
To: dns@list.cr.yp.to
Subject: axfrdns serial number patch
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I was having a problem with a secondary nameserver doing an AXFR update from
axfrdns. I diagnosed the problem and fixed it locally, and only then thought to
check the mailing list archives to see if anybody else had run into this. Sure
enough, I see others had this problem with BIND 9. Below is a simple patch for
version 1.04 that returns the sequence number of the query in the AXFR
response.

Greg Hewgill

--- axfrdns.c.orig	Sun Jan 21 20:51:44 2001
+++ axfrdns.c	Tue Feb  6 15:06:41 2001
@@ -144,7 +144,7 @@
   if (!stralloc_catb(sa,d,dns_domain_length(d))) nomem();
 }
 
-int build(stralloc *sa,char *q,int flagsoa)
+int build(stralloc *sa,char *q,int flagsoa,const char id[2])
 {
   unsigned int rdatapos;
   char misc[20];
@@ -160,6 +160,7 @@
   if (!flagsoa) if (byte_equal(type,2,DNS_T_SOA)) return 0;
 
   if (!stralloc_copyb(sa,"\0\0\200\200\0\0\0\1\0\0\0\0",12)) nomem();
+  sa->s[0] = id[0]; sa->s[1] = id[1];
   copy(misc,1);
   if ((misc[0] == '=' + 1) || (misc[0] == '*' + 1)) {
     --misc[0];
@@ -217,7 +218,7 @@
 static stralloc soa;
 static stralloc message;
 
-void doaxfr(void)
+void doaxfr(const char id[2])
 {
   char key[512];
   uint32 klen;
@@ -252,7 +253,7 @@
     dlen = cdb_datalen(&c);
     if (dlen > sizeof data) die_cdbformat();
     if (cdb_read(&c,data,dlen,cdb_datapos(&c)) == -1) die_cdbformat();
-    if (build(&soa,zone,1)) break;
+    if (build(&soa,zone,1,id)) break;
   }
 
   cdb_free(&c);
@@ -286,7 +287,7 @@
     if (klen < 1) die_cdbformat();
     if (dns_packet_getname(key,klen,0,&q) != klen) die_cdbformat();
     if (!dns_domain_suffix(q,zone)) continue;
-    if (!build(&message,q,0)) continue;
+    if (!build(&message,q,0,id)) continue;
     print(message.s,message.len);
   }
 
@@ -353,7 +354,7 @@
       case_lowerb(zone,zonelen);
       fdcdb = open_read("data.cdb");
       if (fdcdb == -1) die_cdbread();
-      doaxfr();
+      doaxfr(header);
       close(fdcdb);
     }
     else {