Follow the Microsoft DNS client behaviour much more closely.

I have completely redone the update logic to match that documented in
the MMC help (Dns/Concepts/Understanding DNS/Dynamic update).

The client also reads configuration variables from the file
$(sysconfdir)/dnsupdate.conf if it exists. This is intended for
use with group policy.

CHANGES

@@ -1,5 +1,7 @@
 1.3.0.?
-    - bug 484: detect the authoritative domain name by doing a query
+    - use configuration file for options similar to Microsoft's DNS client
+    - follow NS records when primary SOA update fails
+    - bug 484: detect the authoritative domain name by doing an SOA query
     - bug 467: add -r option for PTR updates
     - bug 415: Debian and Ubuntu support
     - fix option processing bug

Makefile.am

@@ -9,13 +9,21 @@ sbin_PROGRAMS = 	dnsupdate
 libexec_SCRIPTS =	dnsupdate-install-hooks
 man_MANS = 		dnsupdate.8 dnsupdate-install-hooks.8
 
-dnsupdate_SOURCES=	dnsupdate.c dns.c dnstcp.c \
-			dnsdebug.c dnstkey.c dnstsig.c \
-			common.h dns.h dnsdebug.h dnstcp.h \
-			dnstkey.h dnstsig.h
+dnsupdate_SOURCES=	dnsupdate.c 
+dnsupdate_SOURCES+=	common.h 
+dnsupdate_SOURCES+=	dns.c dns.h 
+dnsupdate_SOURCES+=	dnsdebug.c dnsdebug.h 
+dnsupdate_SOURCES+=	dnstcp.c dnstcp.h 
+dnsupdate_SOURCES+=	dnstkey.c dnstkey.h 
+dnsupdate_SOURCES+=	dnstsig.c dnstsig.h
+dnsupdate_SOURCES+=	conf.c conf.h
+dnsupdate_SOURCES+=	stream.c stream.h
+dnsupdate_SOURCES+=	resconf.c resconf.h
+dnsupdate_SOURCES+=	list.c list.h
 dnsupdate_LDADD=	$(LIBOBJS)
 dnsupdate_CFLAGS=	$(VAS_CFLAGS)
 dnsupdate_LDFLAGS=	$(VAS_LIBS)
+dnsupdate_CPPFLAGS=	-DPATH_SYSCONFDIR=\"$(sysconfdir)\"
 
 EXTRA_DIST=	$(man_MANS) err.h \
 		dnsupdate-install-hooks.in dnsupdate.pp pp
@@ -49,3 +57,13 @@ SUBDIRS=
 if WITH_IPWATCHD
 SUBDIRS+=	ipwatchd
 endif
+
+check_PROGRAMS=		conf-t
+conf_t_SOURCES=		conf-t.c conf.c conf.h stream.c stream.h
+conf_t_CFLAGS =		-ggdb
+
+check_PROGRAMS+=	list-t
+list_t_SOURCES=		list-t.c list.c list.h
+list_t_CFLAGS =		-ggdb
+
+TESTS=			$(check_PROGRAMS)

conf-t.c

@@ -0,0 +1,73 @@
+
+/* Unit tests for conf */
+
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include "conf.h"
+
+#define TESTFILEPATH "/tmp/_conf_test.txt"
+
+int main()
+{
+    FILE *f;
+
+    config_add("test", "1");
+    assert(config_get_int("test", 2) == 1);
+    assert(strcmp(config_get_string("test", "2"), "1") == 0);
+    assert(config_get_int("unset", 2) == 2);
+    assert(config_get_int("unset", -1) == -1);
+    assert(strcmp(config_get_string("unset", "2"), "2") == 0);
+    assert(config_get_string("unset", NULL) == NULL);
+
+    config_add("test4", "4");
+    assert(config_get_int("test4", 2) == 4);
+    assert(strcmp(config_get_string("test4", "2"), "4") == 0);
+    assert(config_get_int("test", 2) == 1);
+    assert(strcmp(config_get_string("test", "2"), "1") == 0);
+    assert(config_get_int("unset", 2) == 2);
+    assert(strcmp(config_get_string("unset", "2"), "2") == 0);
+
+    config_add("test", "3");
+    assert(config_get_int("test", 2) == 3);
+    assert(strcmp(config_get_string("test", "2"), "3") == 0);
+    assert(config_get_int("unset", 2) == 2);
+    assert(strcmp(config_get_string("unset", "2"), "2") == 0);
+
+    config_add("test", "0x10");
+    assert(config_get_int("test", 99) == 0x10);
+    config_add("test", "077");
+    assert(config_get_int("test", 99) == 077);
+
+    config_add("test", NULL);
+    assert(config_get_string("test", "") == NULL);
+
+    f = fopen(TESTFILEPATH, "w");
+    assert(f != NULL);
+    fprintf(f, "a=a\n"
+	       "b=\n"
+	       " \t c =  \t c c \t c \t \r\n\r\n"
+	       " badline #=\n"		    /* generate error but ignore */
+	       "   \t #comment\n"
+	       "\n"
+	       " d = d # comment\n"
+	       " e =# comment # #\n"
+	       " # f = something\n"
+	       " g = eol \t");
+    fclose(f);
+
+    config_load(TESTFILEPATH);
+    (void)unlink(TESTFILEPATH);
+    assert(strcmp(config_get_string("a", "x"),"a") == 0);
+    assert(strcmp(config_get_string("b", "x"),"") == 0);
+    assert(strcmp(config_get_string("c", "x"),"c c \t c") == 0);
+    assert(strcmp(config_get_string("badline", "x"),"x") == 0);
+    assert(strcmp(config_get_string("d", "x"),"d") == 0);
+    assert(strcmp(config_get_string("e", "x"),"") == 0);
+    assert(strcmp(config_get_string("f", "x"),"x") == 0);
+    assert(strcmp(config_get_string("g", "x"),"eol") == 0);
+
+    exit(0);
+}

conf.c

@@ -0,0 +1,151 @@
+/* (c) 2008, Quest Software, Inc. All rights reserved. */
+
+/*
+ * Simple key-value configuration file interface
+ */
+
+#include "common.h"
+#include "conf.h"
+#include "stream.h"
+
+/* A configuration entry */
+struct config {
+    char *key, *value;
+    struct config *next;
+};
+
+/* Prototypes */
+static const struct config *config_get(const char *key);
+static void config_load_stream(struct stream *stream);
+
+/* A stack of configuration entries. New config entries are pushed onto the
+ * top of the stack. Searches are performed top-down into the stack. */
+static struct config *Config;
+
+/*------------------------------------------------------------
+ * Public functions
+ */
+
+/* Adds a key/value settings into the global configuration */
+void
+config_add(char *key, char *value)
+{
+    struct config *config;
+
+    if (!(config = (struct config *)malloc(sizeof *config))) {
+	fprintf(stderr, "config_add: out of memory\n");
+	exit(1);
+    }
+    config->key = key;
+    config->value = value;
+    config->next = Config;
+    Config = config;
+}
+
+/* Adds settings from a configuration file into the global configuration. */
+void
+config_load(const char *path)
+{
+    struct stream stream;
+
+    if (!stream_init_path(&stream, path))
+	return;
+    config_load_stream(&stream);
+    stream_fini(&stream);
+}
+
+/* Returns a configuration value as an integer.
+ * Returns def_value if no prior configuration is found.
+ * The strings 'yes', 'true', and 'on' are converted to 1.
+ * Numbers beginning with 0x are converted using base 16. 
+ * Numbers beginning with 0 are converted using base 8.
+ * Non-numeric digits are otherwise ignored.
+ * A value with no digits is returned as zero. */
+long 
+config_get_int(const char *key, long def_value)
+{
+    const struct config *config;
+
+    if (!(config = config_get(key)))
+	return def_value;
+    if (strcmp(config->value, "yes") == 0 ||
+	strcmp(config->value, "true") == 0 ||
+	strcmp(config->value, "on") == 0)
+	    return 1;
+    return strtol(config->value, NULL, 0);
+}
+
+/* Returns a configuration value as a nul-terminated C string. 
+ * Returns def_value if the configuration is not found.
+ * Caller must NOT free or alter the returned string. */
+const char *
+config_get_string(const char *key, const char *def_value)
+{
+    const struct config *config;
+
+    if (!(config = config_get(key)))
+	return def_value;
+    return config->value;
+}
+
+/*------------------------------------------------------------
+ * Private config functions
+ */
+
+/* Returns a configuration entry for the given key, or NULL if not found */
+static const struct config *
+config_get(const char *key)
+{
+    struct config *config;
+
+    for (config = Config; config; config = config->next)
+	if (strcmp(key, config->key) == 0)
+	    return config;
+    return NULL;
+}
+
+/* Loads configuration statements from the stream into the global Config */
+static void
+config_load_stream(struct stream *stream)
+{
+    char *key, *value;
+    struct buffer buffer;
+
+    buffer_init(&buffer);
+
+#define WHITESPACE  " \t"
+#define ENDOFLINE   "\n\r"
+
+    for (;;) {
+	/* Ignore to the end of the previous line */
+	stream_while(stream, ENDOFLINE, NULL);	    /* skip line end(s) */
+	stream_while(stream, WHITESPACE, NULL);	    /* skip lead whitespace */
+	if (!stream_ok(stream))			    /* check for end of file */
+	    break;
+	if (stream_nextch(stream) == '#') {	    /* comments start with # */
+	    stream_until(stream, ENDOFLINE, NULL);  /* skip to end of line */
+	    continue;
+	}
+	buffer.len = 0;
+	stream_until(stream, "#=" WHITESPACE, &buffer);	/* read key word */
+	if (!buffer.len) {
+	    stream_error(stream, "missing key");
+	    stream_until(stream, ENDOFLINE, NULL);  /* skip to end of line */
+	    continue;
+	}
+	stream_while(stream, WHITESPACE, NULL);     /* skip whitespace */
+	if (stream_nextch(stream) != '=') {	    /* expect '=' */
+	    stream_error(stream, "expected '='");
+	    stream_until(stream, ENDOFLINE, NULL);  /* skip to end of line */
+	    continue;
+	}
+	stream_getch(stream);			    /* skip '=' */
+	key = buffer_string(&buffer);		    /* also clears buffer */
+	stream_while(stream, WHITESPACE, NULL);	    /* skip whitespace */
+	stream_until(stream, "#" ENDOFLINE, &buffer); /* read value */
+	buffer_rtrim(&buffer, WHITESPACE);	    /* remove trailing space */
+	value = buffer_string(&buffer);		    /* extract value */
+	config_add(key, value);
+    }
+    buffer_fini(&buffer);
+}

conf.h

@@ -0,0 +1,4 @@
+void config_add(char *key, char *value);
+void config_load(const char *path);
+long config_get_int(const char *key, long def_value);
+const char *config_get_string(const char *key, const char *def_value);

dnsdebug.c

@@ -175,6 +175,38 @@ dumpuint32time(struct dns_msg *msg, const char *name)
     fprintf(stderr, "\t%-20s: %.24s (0x%x)\n", name, ctime(&t), v);
 }
 
+static void
+dumpuint32rtime(struct dns_msg *msg, const char *name)
+{
+    static struct {
+	const char *abbrev;
+	uint32_t interval;
+    } intervals[] = {
+	{ "d", 24 * 60 * 60 },
+	{ "h", 60 * 60 },
+	{ "m", 60 },
+	{ "s", 1 },
+    };
+    uint32_t v,t;
+    int i, printed_something = 0;
+
+    v = dns_rd_uint32(msg);
+    t = v;
+    fprintf(stderr, "\t%-20s:", name);
+    for (i = 0; i < sizeof intervals / sizeof intervals[0]; i++) 
+	if (t >= intervals[i].interval || printed_something) {
+	    int x = t / intervals[i].interval;
+	    if (t) {
+		fprintf(stderr, " %d%s", x, intervals[i].abbrev);
+		printed_something = 1;
+	    }
+	    t = t - x * intervals[i].interval;
+	}
+    if (!printed_something)
+	fprintf(stderr, " 0");
+    fprintf(stderr, " (0x%x)\n", v);
+}
+
 static void
 dumpheader(const struct dns_header *hdr)
 {
@@ -296,6 +328,20 @@ dumpmsg(struct dns_msg *msg)
 	    dumpdata(msg, "tkey.key", dns_rd_uint16(msg));
 	    dumpdata(msg, "tkey.other", dns_rd_uint16(msg));
 	    dns_rd_end(msg);
+	} else if (rr.type == 6) {
+	    dns_rd_begin(msg);
+	    dumpname(msg, "soa.mname");
+	    dumpname(msg, "soa.rname");
+	    dumpuint32(msg, "soa.serial");
+	    dumpuint32rtime(msg, "soa.refresh");
+	    dumpuint32rtime(msg, "soa.retry");
+	    dumpuint32rtime(msg, "soa.expire");
+	    dumpuint32(msg, "soa.minttl");
+	    dns_rd_end(msg);
+	} else if (rr.type == 2) {
+	    dns_rd_begin(msg);
+	    dumpname(msg, "ns.nsdname");
+	    dns_rd_end(msg);
 	} else {
 	    len = dns_rd_data(msg, data, sizeof data);
 	    if (len)

dnstcp.c

@@ -155,7 +155,8 @@ dnstcp_send(int s, const void *buf, size_t len)
 	return -1;
     }
     if (verbose > 3) 
-	fprintf(stderr, "dnstcp_send: writing %d bytes to fd %d\n", len, s);
+	fprintf(stderr, "dnstcp_send: writing %d bytes to fd %d\n", 
+		(int)len, s);
     if (len > 0 && write(s, buf, len) != len) {
 	warn("write");
 	return -1;
@@ -198,7 +199,8 @@ dnstcp_recv(int s, void *buf, size_t bufsz)
 	    return 0;
 	}
         if (verbose > 3)
-	   fprintf(stderr, "[read %d of %d header]\n", pos+len, sizeof b);
+	   fprintf(stderr, "[read %d of %d header]\n", pos+len, 
+		   (int)sizeof b);
     }
 
 

dnsupdate.8

@@ -8,6 +8,7 @@ dnsupdate \- updates a DNS entry in Active Directory
 .RI [\-a\  auth-domain ]
 .RI [\-d\  domain ]
 .RI [\-h\  hostname ]
+.RI [\-o\  option = value ]
 .RI [\-s\  nameserver ]
 .RI [\-t\  ttl ]
 .I ip-addr
@@ -53,6 +54,9 @@ The reverse name in in-addr.arpa is computed from the
 .I ipaddr
 and a PTR record update is attempted.
 .TP
+.RI \-o\  option = value
+Overrides an option setting.
+.TP
 .RI \-s\  nameserver
 specifies the nameserver host to send the dynamic DNS update requests to.
 The default is to try all domain controllers, using the nearest first.
@@ -68,6 +72,19 @@ increases the level of verbosity
 .TP
 \-V
 displays version information, then exits.
+.SS OPTIONS
+Options are read from
+/etc/opt/quest/dnsupdate.conf
+before argument processing begins.
+.TP
+.RI UpdateSecurityLevel= integer
+A value of zero (default) indicates that an un-authenticated updated is
+tried first, and then a secure update only if the first fails.
+A value of 16 enables only un-authenticated updates.
+A value of 256 enables only authenticated updates.
+.TP
+.TI DefaultRegistrationTTL= seconds
+The default TTL used 
 .SS "EXIT STATUS"
 The
 .B dnsupdate