Incorporate a bunch of changes from Brian Murrell.

common/nsupdate.c

@@ -25,7 +25,7 @@
 
 #ifndef lint
 static char copyright[] =
-"$Id: nsupdate.c,v 1.8 1999/09/16 01:14:52 mellon Exp $ Copyright (c) 1999 The Internet Software Consortium.  All rights reserved.\n";
+"$Id: nsupdate.c,v 1.9 1999/10/04 23:14:58 mellon Exp $ Copyright (c) 1999 The Internet Software Consortium.  All rights reserved.\n";
 #endif /* not lint */
 
 #include "dhcpd.h"
@@ -36,7 +36,14 @@ static char copyright[] =
    done.  This can be done by figuring out the hostname.domain and revname
    and then comparing them to the lease->ddns* values.  Only make the changes
    necessary which can be any combination and number of remove A, add A,
-   remove PTR, add PTR */
+   remove PTR, add PTR.
+
+   Wed Sep 29 02:06:33 PDT 1999
+   SCRAP THAT!  Let the DNS server determine whether an add/delete should
+   be done by giving it pre-requisites to the add/delete.
+ */
+
+#define NAME(x)	(x) ? (char *)(x) : "(null)"
 
 #if 0
 /* Return the reverse name of a lease. */
@@ -183,90 +190,153 @@ char *ddns_fwd_name(lease, state, packet)
 #endif
 	return hostname;
 }
-#endif
+#endif /* 0 */
 
-static int nsupdateA(hostname, ip_addr, ttl, opcode)
-	char *hostname;
-	unsigned char *ip_addr;
+int nsupdateA (hostname, ip_addr, ttl, opcode)
+	const char *hostname;
+	const unsigned char *ip_addr;
 	u_int32_t ttl;
-	int	opcode;
+	int opcode;
 {
-	int 	z;
-	ns_updrec	*u, *n;
+	int z;
+	ns_updrec *p, *u;
+
+	/* set up update section */
+	if (!(u = res_mkupdrec (S_UPDATE, hostname, C_IN, T_A, ttl)))
+		return 0;
+	u -> r_opcode = opcode;
+	u -> r_data = (char *)ip_addr;
+
+#if 0 /* no PREREQUISITES are needed for adds and deletes, as there is no zone
+	 churn when you add a record that exists or delete a record that
+	 doesn't exist */
+
+	/* set up the prerequisite section */
+	if (!(p = res_mkupdrec (S_PREREQ, hostname, C_IN, T_A, 0))) {
+		res_freeupdrec (u);
+		return 0;
+	}
+	p -> r_next = u;
+	p -> r_data = (char *)ip_addr;
+#endif
 
 	switch (opcode) {
-	case ADD:
-		if (!(u = res_mkupdrec(S_PREREQ, hostname, C_IN, T_A, 0))) 
-			return 0;
-		u->r_opcode = NXRRSET; u->r_data = NULL; u->r_size = 0;
-		if (!(n = res_mkupdrec(S_UPDATE, hostname, C_IN, T_A, ttl))) {
-			res_freeupdrec(u);
+	      case ADD:
+		if (!ip_addr) {		/* can't have NULL ip_addr for an ADD */
+#if 0
+			res_freeupdrec (p);
+#endif
+			res_freeupdrec (u);
 			return 0;
 		}
-		n->r_opcode = opcode;
-		n->r_data = ip_addr;
-		n->r_size = strlen((const char *)n->r_data);
-		u->r_next = n;
-		z = res_update(u);
-		log_info("add %s: %s %d IN A %s",
-			 z == 1 ? "succeeded" : "failed", hostname, ttl,
-			 n->r_data);
-		res_freeupdrec(u); 
-		res_freeupdrec(n);
-/* do we really need to do this?  If so, it needs to be done elsewehere as
-   this function is strictly for manipulating the A record
-		if (z < 1) 
-			return 0;
-*/
-		/* delete all PTR RRs with the same ip address. Wow! */
-/*
-		if (!(u = res_mkupdrec(S_UPDATE, revname, C_IN, T_PTR, 0)))
-			return 0;
-		u->r_opcode = DELETE; u->r_data = NULL; u->r_size = 0;
-		log_info("cleaning all PTR RRs for %s", revname);
-		res_update(u);
-		res_freeupdrec(u);
-*/
+#if 0
+		/* PREQUISITE: add only if the RR is not there already */
+		p -> r_opcode = NXRRSET;
+		p -> r_size = strlen ((const char *)p -> r_data);
+#endif
+		u -> r_size = strlen ((const char *)u -> r_data);
 		break;
-	case	DELETE:
-		ttl = 0;
-		if (!(u = res_mkupdrec(S_UPDATE, hostname, C_IN, T_A, ttl)))
-			return 0;
-		u->r_opcode = opcode;
-		u->r_data = ip_addr;
-		u->r_size = strlen((const char *)u->r_data);
-		z = res_update(u);
-		log_info("delete %s: %s %d IN A %s",
-			 z == 1 ? "succeeded" : "failed",
-			 hostname, ttl, u->r_data);
-		res_freeupdrec(u);
+	      case DELETE:
+		ttl = 0;	/* delete updates ALWAYS have a 0 TTL */
+#if 0
+		/* PREQUISITE: delete only if the RR to be deleted is there */
+		p -> r_opcode = YXRRSET;
+#endif
+		/* NOTE: ip_addr could be NULL for a "DELETE all records" */
+		if (u -> r_data) {
+#if 0
+			p -> r_size = strlen ((const char *)n -> r_data);
+#endif
+			u -> r_size = strlen ((const char *)u -> r_data);
+		} else {
+#if 0
+			p -> r_size = 0;
+#endif
+			u -> r_size = 0;
+		}
 		break;
 	}
+	z = res_update (u);
+	log_info ("%s %s: %s %d IN A %s", opcode == ADD ? "add" : "delete",
+		  z == 1 ? "succeeded" : "failed", NAME (hostname), ttl,
+		  NAME (u -> r_data));
+#if 0
+	res_freeupdrec (p);
+#endif
+	res_freeupdrec (u);
 	return z;
 }
 
-static int nsupdatePTR(revname, hostname, ttl, opcode)
-	unsigned char *hostname;
-	char *revname;
+int nsupdatePTR (revname, hostname, ttl, opcode)
+	const char *revname;
+	const unsigned char *hostname;
 	u_int32_t ttl;
-	int	opcode;
+	int opcode;
 {
-	int 	z;
-	ns_updrec	*u;
+	int z;
+	ns_updrec *u, *p;
 
-	if (opcode == DELETE)
-		ttl = 0;
-	if (!(u = res_mkupdrec(S_UPDATE, revname, C_IN, T_PTR, ttl)))
+	/* set up update section */
+	if (!(u = res_mkupdrec (S_UPDATE, revname, C_IN, T_PTR, ttl)))
+		return 0;
+	u -> r_opcode = opcode;
+	u -> r_data = (char *)hostname;
+
+#if 0 /* don't need PREREQUISITES */
+	/* set up the prerequisite section */
+	if (!(p = res_mkupdrec (S_PREREQ, revname, C_IN, T_PTR, 0))) {
+		res_freeupdrec (u);
 		return 0;
-	u->r_opcode = opcode;
-	u->r_data = hostname;
-	u->r_size = strlen((const char *)u->r_data);
+	}
+	p -> r_next = u;
+	p -> r_data = (char *)hostname;
+#endif
+	
+	switch (opcode) {
+	      case ADD:
+		if (!hostname) {	/* can't have NULL ip_addr for an ADD */
+#if 0
+			res_freeupdrec (p);
+#endif
+			res_freeupdrec (u);
+			return 0;
+		}
+#if 0
+		/* PREQUISITE: add only if the RR is not there already */
+		p -> r_opcode = NXRRSET;
+		p -> r_size = strlen ((const char *)p -> r_data);
+#endif
+		u -> r_size = strlen ((const char *)u -> r_data);
+		
+		break;
+	      case DELETE:
+		ttl = 0;	/* delete updates ALWAYS have a 0 TTL */	
+#if 0
+		/* PREQUISITE: delete only if the RR to be deleted is there */
+		p->r_opcode = YXRRSET;
+		/* NOTE: hostname could be NULL for a "DELETE all records" */
+#endif
+		if (u -> r_data) {
+#if 0
+			p -> r_size = strlen ((const char *)p -> r_data);
+#endif
+			u -> r_size = strlen ((const char *)u -> r_data);
+		} else {
+#if 0
+			p -> r_size = 0;
+#endif
+			u -> r_size = 0;
+		}
+		break;
+	}
 	z = res_update(u);
-	log_info("%s %s: %s %d IN PTR %s", 
-		 opcode == ADD ? "add" : 
-				 "delete", z == 1 ? "succeeded" : "failed",
-		 revname, ttl, hostname);
-	res_freeupdrec(u);
+	log_info ("%s %s: %s %d IN PTR %s", opcode == ADD ? "add" : 
+		  "delete", z == 1 ? "succeeded" : "failed",
+		  NAME (revname), ttl, NAME (u -> r_data));
+#if 0
+	res_freeupdrec (p);
+#endif
+	res_freeupdrec (u);
 	return z;
 }
 
@@ -417,93 +487,99 @@ return;
 }
 #endif
 
-/* public function to update an A record if needed */
-int updateA(struct data_string *lhs, struct data_string *rhs, unsigned int ttl,
-	struct lease *lease)
+/* public function to update an A record */
+int updateA (lhs, rhs, ttl, lease)
+	const struct data_string *lhs;
+	const struct data_string *rhs;
+	unsigned int ttl;
+	struct lease *lease;
 {
 
 	static char hostname[MAXDNAME];
 	static char ipaddr[MAXDNAME];
+	int y;
 
 	hostname[0] = '\0';
-	strncat(hostname, (const char *)lhs->data, lhs->len);
-	hostname[lhs->len] = '\0';
+	strncat(hostname, (const char *)lhs -> data, lhs -> len);
+	hostname[lhs -> len] = '\0';
 	
 	ipaddr[0] = '\0';
-	strncat(ipaddr, (const char *)rhs->data, rhs->len);
-	ipaddr[rhs->len] = '\0';
-	
-	/* delete an existing A if the one to be added is different */
-	if (lease -> ddns_fwd_name &&
-	    strcmp(hostname, lease -> ddns_fwd_name)) {
-		int y;
-		y=nsupdateA(lease -> ddns_fwd_name, ipaddr, 0, DELETE);
-
-		if (y) {
-			/* clear the forward DNS name pointer */
-			if (lease -> ddns_fwd_name)
-				dfree(lease -> ddns_fwd_name, "nsupdate");
-			lease -> ddns_fwd_name = 0;
-		}
-	}
-	/* only update if there is no A record there already */
-	if (!lease -> ddns_fwd_name) {
-		int y;
-	    	y=nsupdateA(hostname, ipaddr, ttl, ADD);
-		if (y < 1)
-			return 0;
+	strncat(ipaddr, (const char *)rhs -> data, rhs -> len);
+	ipaddr[rhs -> len] = '\0';
+
+#if 0	/* Wrong!  This causes zone churn on every DHCPREQUEST!
+	   Besides, it is perfectly legal for a DHCP client to have more
+	   than one lease, if (say) it was being served by two+ DHCP servers
+	   serving the same subnet with different (i.e. disjoint) pools.
+	   The right thing to do is have the A records cleaned by either a
+	   DHCPRELEASE or the lease expiry.  */
+    
+	/* delete all existing A records for this host */
+	nsupdateA (hostname, NULL, 0, DELETE);
+#endif
 
-		/* remember this in the lease structure for release */
-		lease -> ddns_fwd_name = dmalloc(strlen(hostname) + 1,
-					 	 "nsupdate");
-		strcpy (lease -> ddns_fwd_name, hostname);
-	}
+	/* clear the forward DNS name pointer */
+	if (lease -> ddns_fwd_name)
+		dfree (lease -> ddns_fwd_name, "nsupdate");
+	lease -> ddns_fwd_name = 0;
+
+	y=nsupdateA (hostname, ipaddr, ttl, ADD);
+	if (y < 1)
+		return 0;
+
+	/* remember this in the lease structure for release */
+	lease -> ddns_fwd_name = dmalloc (strlen(hostname) + 1, "nsupdate");
+	strcpy (lease -> ddns_fwd_name, hostname);
 
 	return 1;
 }
 
-/* public function to update an A record if needed */
-int updatePTR(struct data_string *lhs, struct data_string *rhs,
-	      unsigned int ttl, struct lease *lease)
+/* public function to update an PTR record */
+int updatePTR (lhs, rhs, ttl, lease)
+	const struct data_string *lhs;
+	const struct data_string *rhs;
+	unsigned int ttl;
+	struct lease *lease;
 {
 
 	static char hostname[MAXDNAME];
 	static char revname[MAXDNAME];
+	int y;
 
 	revname[0] = '\0';
-	strncat(revname, (const char *)lhs->data, lhs->len);
-	revname[lhs->len] = '\0';
+	strncat(revname, (const char *)lhs -> data, lhs -> len);
+	revname[lhs -> len] = '\0';
 
 	hostname[0] = '\0';
-	strncat(hostname, (const char *)rhs->data, rhs->len);
-	hostname[rhs->len] = '\0';
-	
-	/* delete an existing PTR if the one to be added is different */
-	if (lease -> ddns_rev_name &&
-	    strcmp(revname, lease -> ddns_rev_name)) {
-		int y;
-		y=nsupdatePTR(revname, hostname, 0, DELETE);
-
-		if (y) {
-			/* clear the reverse DNS name pointer */
-			if (lease -> ddns_rev_name)
-				dfree(lease -> ddns_rev_name, "nsupdate");
-			lease -> ddns_rev_name = 0;
-		}
-	}
-	/* only update if there is no PTR record there already */
-	if (!lease -> ddns_rev_name) {
-		int y;
-	    	y=nsupdatePTR(revname, hostname, ttl, ADD);
-		if (y < 1)
-			return 0;
+	strncat(hostname, (const char *)rhs -> data, rhs -> len);
+	hostname[rhs -> len] = '\0';
+
+#if 0	/* Wrong!  This causes zone churn on every DHCPREQUEST!
+	   Besides, it is perfectly legal for a DHCP client to have more
+	   than one lease, if (say) it was being served by two+ DHCP servers
+	   serving the same subnet with different (i.e. disjoint) pools.
+	   The right thing to do is have the PTR records cleaned by either a
+	   DHCPRELEASE or the lease expiry.  */
+ 	
+	/* delete all existing PTR records */
+	nsupdatePTR (revname, NULL, 0, DELETE);
+#endif
 
-		/* remember this in the lease structure for release */
-		lease -> ddns_rev_name = dmalloc(strlen(revname) + 1,
-					 	 "nsupdate");
-		strcpy (lease -> ddns_rev_name, revname);
-	}
+	/* clear the reverse DNS name pointer */
+	if (lease -> ddns_rev_name)
+		dfree (lease -> ddns_rev_name, "nsupdate");
+	lease -> ddns_rev_name = 0;
+
+	y=nsupdatePTR (revname, hostname, ttl, ADD);
+	if (y < 1)
+		return 0;
+
+	/* remember this in the lease structure for release */
+	lease -> ddns_rev_name = dmalloc (strlen(revname) + 1, "nsupdate");
+	strcpy (lease -> ddns_rev_name, revname);
 
 	return 1;
 }
 #endif /* defined (NSUPDATE) */
+
+/* vim: set tabstop=8: */

common/tree.c

@@ -22,7 +22,7 @@
 
 #ifndef lint
 static char copyright[] =
-"$Id: tree.c,v 1.51 1999/09/24 19:04:30 mellon Exp $ Copyright (c) 1995, 1996, 1997, 1998 The Internet Software Consortium.  All rights reserved.\n";
+"$Id: tree.c,v 1.52 1999/10/04 23:15:43 mellon Exp $ Copyright (c) 1995, 1996, 1997, 1998 The Internet Software Consortium.  All rights reserved.\n";
 #endif /* not lint */
 
 #include "dhcpd.h"
@@ -575,15 +575,16 @@ int evaluate_boolean_expression (result, packet, lease, in_options,
 				log_debug("calling updateA(%s, %s, %d, lease)",
 					  expr1.data , expr2.data, ttl);
 #endif
-				updateA(expr1, expr2, ttl, lease);
+				updateA(&expr1, &expr2, ttl, lease);
 			} else if (rrtype.len == 3 &&
-				   strncmp((const char *)rrtype.data, "ptr", 3) == 0) {
+				   strncmp((const char *)rrtype.data,
+					    "ptr", 3) == 0) {
 #if defined (DEBUG_EXPRESSIONS)
 				log_debug ("%s updatePTR(%s, %s, %d, lease)",
 					   "calling", expr1.data,
 					   expr2.data, ttl);
 #endif
-				updatePTR(expr1, expr2, ttl, lease);
+				updatePTR(&expr1, &expr2, ttl, lease);
 			}
 			*result = 1;
 		} else {
@@ -2182,3 +2183,4 @@ int write_expression (file, expr, col, indent)
 	}
 	return col;
 }
+/* vim: set tabstop=8: */