From: Baptiste Assmann <bedis9@gmail.com>
Date: Thu, 2 Feb 2017 21:44:15 +0000 (+0100)
Subject: MINOR: dns: give ability to dns_init_resolvers() to close a socket when requested
X-Git-Tag: v1.8-dev1~145
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=5cd1b9222eabcd73f387fd65b075b2af59014558;p=thirdparty%2Fhaproxy.git

MINOR: dns: give ability to dns_init_resolvers() to close a socket when requested

The function dns_init_resolvers() is used to initialize socket used to
send DNS queries.
This patch gives the function the ability to close a socket before
re-opening it.

[wt: this needs to be backported to 1.7 for next fix]
---

diff --git a/include/proto/dns.h b/include/proto/dns.h
index c62834f94e..c7cd3564b2 100644
--- a/include/proto/dns.h
+++ b/include/proto/dns.h
@@ -30,7 +30,7 @@ int dns_str_to_dn_label_len(const char *string);
 int dns_hostname_validation(const char *string, char **err);
 int dns_build_query(int query_id, int query_type, char *hostname_dn, int hostname_dn_len, char *buf, int bufsize);
 struct task *dns_process_resolve(struct task *t);
-int dns_init_resolvers(void);
+int dns_init_resolvers(int close_socket);
 uint16_t dns_rnd16(void);
 int dns_validate_dns_response(unsigned char *resp, unsigned char *bufend, struct dns_response_packet *dns_p);
 int dns_get_ip_from_response(struct dns_response_packet *dns_p,
diff --git a/src/dns.c b/src/dns.c
index 2a333f1d31..5542b17c6f 100644
--- a/src/dns.c
+++ b/src/dns.c
@@ -919,11 +919,13 @@ unsigned short dns_response_get_query_id(unsigned char *resp)
  * parses resolvers sections and initializes:
  *  - task (time events) for each resolvers section
  *  - the datagram layer (network IO events) for each nameserver
+ * It takes one argument:
+ *  - close_first takes 2 values: 0 or 1. If 1, the connection is closed first.
  * returns:
  *  0 in case of error
  *  1 when no error
  */
-int dns_init_resolvers(void)
+int dns_init_resolvers(int close_socket)
 {
 	struct dns_resolvers *curr_resolvers;
 	struct dns_nameserver *curnameserver;
@@ -961,7 +963,19 @@ int dns_init_resolvers(void)
 		curr_resolvers->t = t;
 
 		list_for_each_entry(curnameserver, &curr_resolvers->nameserver_list, list) {
-			if ((dgram = calloc(1, sizeof(*dgram))) == NULL) {
+		        dgram = NULL;
+
+			if (close_socket == 1) {
+				if (curnameserver->dgram) {
+					close(curnameserver->dgram->t.sock.fd);
+					memset(curnameserver->dgram, '\0', sizeof(*dgram));
+					dgram = curnameserver->dgram;
+				}
+			}
+
+			/* allocate memory only if it has not already been allocated
+			 * by a previous call to this function */
+			if (!dgram && (dgram = calloc(1, sizeof(*dgram))) == NULL) {
 				Alert("Starting [%s/%s] nameserver: out of memory.\n", curr_resolvers->id,
 						curnameserver->id);
 				return 0;
diff --git a/src/haproxy.c b/src/haproxy.c
index 4ad370d655..6a8b5c2450 100644
--- a/src/haproxy.c
+++ b/src/haproxy.c
@@ -1176,7 +1176,7 @@ static void init(int argc, char **argv)
 		exit(1);
 
 	/* initialize structures for name resolution */
-	if (!dns_init_resolvers())
+	if (!dns_init_resolvers(0))
 		exit(1);
 
 	free(err_msg);