Reduce duplication of common DNS code.

The NAPTR and SRV branches were worked on independently and
resulted in some code being duplicated in each. Since both
have been merged into trunk now, this patch reduces the
duplication by factoring out common code into its own
source files.



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@434490 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 7 insertions, 73 deletions

diff --git a/main/dns_naptr.c b/main/dns_naptr.c
index 7e870002f..72f28dc81 100644
--- a/main/dns_naptr.c
+++ b/main/dns_naptr.c
@@ -392,54 +392,10 @@ struct ast_dns_record *dns_naptr_alloc(struct ast_dns_query *query, const char *
 	char *regexp;
 	char replacement[256] = "";
 	int replacement_size;
-	char *naptr_offset;
-	char *naptr_search_base = (char *)query->result->answer;
-	size_t remaining_size = query->result->answer_size;
-	char *end_of_record;
+	const char *end_of_record;
 	enum flags_result flags_res;
 
-	/*
-	 * This is bordering on the hackiest thing I've ever written.
-	 * Part of parsing a NAPTR record is to parse a potential replacement
-	 * domain name. Decoding this domain name requires the use of the
-	 * dn_expand() function. This function requires that the domain you
-	 * pass in be a pointer to within the full DNS answer. Unfortunately,
-	 * libunbound gives its RRs back as copies of data from the DNS answer
-	 * instead of pointers to within the DNS answer. This means that in order
-	 * to be able to parse the domain name correctly, I need to find the
-	 * current NAPTR record inside the DNS answer and operate on it. This
-	 * loop is designed to find the current NAPTR record within the full
-	 * DNS answer and set the "ptr" variable to the beginning of the
-	 * NAPTR RDATA
-	 */
-	while (1) {
-		naptr_offset = memchr(naptr_search_base, data[0], remaining_size);
-
-		/* Since the NAPTR record we have been given came from the DNS answer,
-		 * we should never run into a situation where we can't find ourself
-		 * in the answer
-		 */
-		ast_assert(naptr_offset != NULL);
-		ast_assert(naptr_search_base + remaining_size - naptr_offset >= size);
-
-		/* ... but just to be on the safe side, let's be sure we can break
-		 * out if the assertion doesn't hold
-		 */
-		if (!naptr_offset || naptr_search_base + remaining_size - naptr_offset < size) {
-			ast_log(LOG_ERROR, "Failed to locate NAPTR record within DNS result\n");
-			return NULL;
-		}
-
-		if (!memcmp(naptr_offset, data, size)) {
-			/* BAM! FOUND IT! */
-			ptr = naptr_offset;
-			break;
-		}
-		/* Data didn't match us, so keep looking */
-		remaining_size -= naptr_offset - naptr_search_base;
-		naptr_search_base = naptr_offset + 1;
-	}
-
+	ptr = dns_find_record(data, size, query->result->answer, query->result->answer_size);
 	ast_assert(ptr != NULL);
 
 	end_of_record = ptr + size;
@@ -451,53 +407,31 @@ struct ast_dns_record *dns_naptr_alloc(struct ast_dns_query *query, const char *
 	 * 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;
-	if (PAST_END_OF_RECORD) {
-		return NULL;
-	}
-	flags = ptr;
-	ptr += flags_size;
+	ptr += dns_parse_string(ptr, &flags_size, &flags);
 	if (PAST_END_OF_RECORD) {
 		return NULL;
 	}
 
 	/* SERVICES */
-	services_size = *ptr;
-	++ptr;
-	if (PAST_END_OF_RECORD) {
-		return NULL;
-	}
-	services = ptr;
-	ptr += services_size;
+	ptr += dns_parse_string(ptr, &services_size, &services);
 	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;
 	}