local-bind: Support binding to local interface/IPs

Add 3 new functions to set the local binding for the out-going
socket connection, and add ares_set_servers_csv() to set a
list of servers at once as a comma-separated string.

Signed-off-by: Ben Greear <greearb@candelatech.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/ares.h b/ares.h
index 368c73a..3b4ff13 100644
--- a/ares.h
+++ b/ares.h
@@ -313,6 +313,20 @@ CARES_EXTERN void ares_destroy(ares_channel channel);
 
 CARES_EXTERN void ares_cancel(ares_channel channel);
 
+/* These next 3 configure local binding for the out-going socket
+ * connection.  Use these to specify source IP and/or network device
+ * on multi-homed systems.
+ */
+CARES_EXTERN void ares_set_local_ip4(ares_channel channel, uint32_t local_ip);
+
+/* local_ip6 should be 16 bytes in length */
+CARES_EXTERN void ares_set_local_ip6(ares_channel channel,
+                                     const unsigned char* local_ip6);
+
+/* local_dev_name should be null terminated. */
+CARES_EXTERN void ares_set_local_dev(ares_channel channel,
+                                     const char* local_dev_name);
+
 CARES_EXTERN void ares_set_socket_callback(ares_channel channel,
                                            ares_sock_create_callback callback,
                                            void *user_data);
@@ -496,6 +510,7 @@ CARES_EXTERN void ares_free_data(void *dataptr);
 
 CARES_EXTERN const char *ares_strerror(int code);
 
+/* TODO:  Hold port here as well. */
 struct ares_addr_node {
   struct ares_addr_node *next;
   int family;
@@ -508,6 +523,10 @@ struct ares_addr_node {
 CARES_EXTERN int ares_set_servers(ares_channel channel,
                                   struct ares_addr_node *servers);
 
+/* Incomming string format: host[:port][,host[:port]]... */
+CARES_EXTERN int ares_set_servers_csv(ares_channel channel,
+                                      const char* servers);
+
 CARES_EXTERN int ares_get_servers(ares_channel channel,
                                   struct ares_addr_node **servers);