[asterisk-commits] mmichelson: branch group/dns r434153 - in /team/group/dns: include/asterisk/ ...

[SVN commits to the Asterisk project]

Author: mmichelson
Date: Mon Apr  6 15:58:12 2015
New Revision: 434153

URL: http://svnview.digium.com/svn/asterisk?view=rev&rev=434153
Log:
Move some common parsing functions to the DNS core.


Modified:
    team/group/dns/include/asterisk/dns_internal.h
    team/group/dns/main/dns_core.c
    team/group/dns/main/dns_naptr.c
    team/group/dns/main/dns_srv.c

Modified: team/group/dns/include/asterisk/dns_internal.h
URL: http://svnview.digium.com/svn/asterisk/team/group/dns/include/asterisk/dns_internal.h?view=diff&rev=434153&r1=434152&r2=434153
==============================================================================
--- team/group/dns/include/asterisk/dns_internal.h (original)
+++ team/group/dns/include/asterisk/dns_internal.h Mon Apr  6 15:58:12 2015
@@ -219,3 +219,25 @@
  * \param response_size The size of the complete DNS response
  */
 char *dns_find_record(const char *record, size_t record_size, const char *response, size_t response_size);
+
+/*!
+ * \brief Parse a 16-bit unsigned value from a DNS record
+ *
+ * \param cur Pointer to the location of the 16-bit value in the DNS record
+ * \param[out] val The parsed 16-bit unsigned integer
+ * \return The number of bytes consumed while parsing
+ */
+int dns_parse_short(unsigned char *cur, uint16_t *val);
+
+/*!
+ * \brief Parse a DNS string from a DNS record
+ *
+ * A DNS string consists of an 8-bit size, followed by the
+ * string value (not NULL-terminated).
+ *
+ * \param cur Pointer to the location of the DNS string
+ * \param[out] size The parsed size of the DNS string
+ * \param[out] val The contained string (not NULL-terminated)
+ * \return The number of bytes consumed while parsing
+ */
+int dns_parse_string(char *cur, uint8_t *size, char **val);

Modified: team/group/dns/main/dns_core.c
URL: http://svnview.digium.com/svn/asterisk/team/group/dns/main/dns_core.c?view=diff&rev=434153&r1=434152&r2=434153
==============================================================================
--- team/group/dns/main/dns_core.c (original)
+++ team/group/dns/main/dns_core.c Mon Apr  6 15:58:12 2015
@@ -631,3 +631,22 @@
 		search_base = record_offset + 1;
 	}
 }
+
+int dns_parse_short(unsigned char *cur, uint16_t *val)
+{
+	/* This assignment takes a big-endian 16-bit value and stores it in the
+	 * machine's native byte order. Using this method allows us to avoid potential
+	 * alignment issues in case the order is not on a short-addressable boundary.
+	 * See http://commandcenter.blogspot.com/2012/04/byte-order-fallacy.html for
+	 * more information
+	 */
+	*val = (cur[1] << 0) | (cur[0] << 8);
+	return sizeof(*val);
+}
+
+int dns_parse_string(char *cur, uint8_t *size, char **val)
+{
+	*size = *cur++;
+	*val = cur;
+	return *size + 1;
+}

Modified: team/group/dns/main/dns_naptr.c
URL: http://svnview.digium.com/svn/asterisk/team/group/dns/main/dns_naptr.c?view=diff&rev=434153&r1=434152&r2=434153
==============================================================================
--- team/group/dns/main/dns_naptr.c (original)
+++ team/group/dns/main/dns_naptr.c Mon Apr  6 15:58:12 2015
@@ -407,54 +407,31 @@
 	 * See http://commandcenter.blogspot.com/2012/04/byte-order-fallacy.html for
 	 * more information
 	 */
-	order = ((unsigned char)(ptr[1]) << 0) | ((unsigned char)(ptr[0]) << 8);
-	ptr += 2;
-
+	ptr += dns_parse_short((unsigned char *) ptr, &order);
 	if (PAST_END_OF_RECORD) {
 		return NULL;
 	}
 
 	/* PREFERENCE */
-	preference = ((unsigned char) (ptr[1]) << 0) | ((unsigned char)(ptr[0]) << 8);
-	ptr += 2;
-
+	ptr += dns_parse_short((unsigned char *) ptr, &preference);
 	if (PAST_END_OF_RECORD) {
 		return NULL;
 	}
 
 	/* FLAGS */
-	flags_size = *ptr;
-	++ptr;
+	ptr += dns_parse_string(ptr, &flags_size, &flags);
 	if (PAST_END_OF_RECORD) {
 		return NULL;
 	}
 
-	flags = ptr;
-	ptr += flags_size;
+	/* SERVICES */
+	ptr += dns_parse_string(ptr, &services_size, &services);
 	if (PAST_END_OF_RECORD) {
 		return NULL;
 	}
 
-	/* SERVICES */
-	services_size = *ptr;
-	++ptr;
-	if (PAST_END_OF_RECORD) {
-		return NULL;
-	}
-	services = ptr;
-	ptr += services_size;
-	if (PAST_END_OF_RECORD) {
-		return NULL;
-	}
-
 	/* REGEXP */
-	regexp_size = *ptr;
-	++ptr;
-	if (PAST_END_OF_RECORD) {
-		return NULL;
-	}
-	regexp = ptr;
-	ptr += regexp_size;
+	ptr += dns_parse_string(ptr, &regexp_size, &regexp);
 	if (PAST_END_OF_RECORD) {
 		return NULL;
 	}

Modified: team/group/dns/main/dns_srv.c
URL: http://svnview.digium.com/svn/asterisk/team/group/dns/main/dns_srv.c?view=diff&rev=434153&r1=434152&r2=434153
==============================================================================
--- team/group/dns/main/dns_srv.c (original)
+++ team/group/dns/main/dns_srv.c Mon Apr  6 15:58:12 2015
@@ -58,25 +58,19 @@
 	end_of_record = ptr + size;
 
 	/* PRIORITY */
-	priority = ((unsigned char)(ptr[1]) << 0) | ((unsigned char)(ptr[0]) << 8);
-	ptr += 2;
-
+	ptr += dns_parse_short((unsigned char *) ptr, &priority);
 	if (ptr >= end_of_record) {
 		return NULL;
 	}
 
 	/* WEIGHT */
-	weight = ((unsigned char)(ptr[1]) << 0) | ((unsigned char)(ptr[0]) << 8);
-	ptr += 2;
-
+	ptr += dns_parse_short((unsigned char *) ptr, &weight);
 	if (ptr >= end_of_record) {
 		return NULL;
 	}
 
 	/* PORT */
-	port = ((unsigned char)(ptr[1]) << 0) | ((unsigned char)(ptr[0]) << 8);
-	ptr += 2;
-
+	ptr += dns_parse_short((unsigned char *) ptr, &port);
 	if (ptr >= end_of_record) {
 		return NULL;
 	}