MXS-1635 Allow using specific address when connecting

In some cases you might want to use a specific address/interface
when connecting to a server instead of the default one. With the
global parameter 'local_address' it can now be specified which
address to use.

Documentation/Getting-Started/Configuration-Guide.md

@@ -537,6 +537,17 @@ This will log all statements that cannot be parsed completely. This may be
 useful if you suspect that MariaDB MaxScale routes statements to the wrong
 server (e.g. to a slave instead of to a master).
 
+#### `local_address`
+
+What specific local address/interface to use when connecting to servers.
+
+This can be used for ensuring that MaxScale uses a particular interface
+when connecting to servers, in case the computer MaxScale is running on
+has multiple interfaces.
+```
+local_address=192.168.1.254
+```
+
 ### Service
 
 A service represents the database service that MariaDB MaxScale offers to the

Documentation/Release-Notes/MaxScale-2.1.14-Release-Notes.md

@@ -0,0 +1,63 @@
+# MariaDB MaxScale 2.1.14 Release Notes
+
+Release 2.1.14 is a GA release.
+
+This document describes the changes in release 2.1.14, when compared
+to release [2.1.13](MaxScale-2.1.13-Release-Notes.md).
+
+If you are upgrading from release 2.0, please also read the following
+release notes:
+
+* [2.1.13](./MaxScale-2.1.13-Release-Notes.md)
+* [2.1.12](./MaxScale-2.1.12-Release-Notes.md)
+* [2.1.11](./MaxScale-2.1.11-Release-Notes.md)
+* [2.1.10](./MaxScale-2.1.10-Release-Notes.md)
+* [2.1.9](./MaxScale-2.1.9-Release-Notes.md)
+* [2.1.8](./MaxScale-2.1.8-Release-Notes.md)
+* [2.1.7](./MaxScale-2.1.7-Release-Notes.md)
+* [2.1.6](./MaxScale-2.1.6-Release-Notes.md)
+* [2.1.5](./MaxScale-2.1.5-Release-Notes.md)
+* [2.1.4](./MaxScale-2.1.4-Release-Notes.md)
+* [2.1.3](./MaxScale-2.1.3-Release-Notes.md)
+* [2.1.2](./MaxScale-2.1.2-Release-Notes.md)
+* [2.1.1](./MaxScale-2.1.1-Release-Notes.md)
+* [2.1.0](./MaxScale-2.1.0-Release-Notes.md)
+
+For any problems you encounter, please consider submitting a bug report at
+[Jira](https://jira.mariadb.org).
+
+## New Features
+
+### Local Address
+
+It is now possible to specify what local address MaxScale should
+use when connecting to servers. Please refer to the documentation
+for [details](../Getting-Started/Configuration-Guide.md#local_address).
+
+## Bug fixes
+
+[Here is a list of bugs fixed in MaxScale 2.1.14.](https://jira.mariadb.org/issues/?jql=project%20%3D%20MXS%20AND%20issuetype%20%3D%20Bug%20AND%20status%20%3D%20Closed%20AND%20fixVersion%20%3D%202.1.14)
+
+* [MXS-1627](https://jira.mariadb.org/browse/MXS-1627) MySQLAuth loads users that use authentication plugins
+* [MXS-1620](https://jira.mariadb.org/browse/MXS-1620) CentOS package symbols are stripped
+* [MXS-1602](https://jira.mariadb.org/browse/MXS-1602) cannot connect to maxinfo with python client
+* [MXS-1601](https://jira.mariadb.org/browse/MXS-1601) maxinfo crash at execute query 'flush;'
+* [MXS-1600](https://jira.mariadb.org/browse/MXS-1600) maxscale it seen to not coop well with lower-case-table-names=1 on cnf
+* [MXS-1576](https://jira.mariadb.org/browse/MXS-1576) Maxscale crashes when starting if .avro and .avsc files are present
+* [MXS-1543](https://jira.mariadb.org/browse/MXS-1543) Avrorouter doesn't detect MIXED or STATEMENT format replication
+* [MXS-1416](https://jira.mariadb.org/browse/MXS-1416) maxscale should not try to do anything when started with --config-check
+
+## Packaging
+
+RPM and Debian packages are provided for the Linux distributions supported by
+MariaDB Enterprise.
+
+Packages can be downloaded [here](https://mariadb.com/resources/downloads).
+
+## Source Code
+
+The source code of MaxScale is tagged at GitHub with a tag, which is identical
+with the version of MaxScale. For instance, the tag of version X.Y.Z of MaxScale
+is maxscale-X.Y.Z.
+
+The source code is available [here](https://github.com/mariadb-corporation/MaxScale).

include/maxscale/config.h

@@ -77,6 +77,7 @@ typedef struct
     char*         qc_args;                             /**< Arguments for the query classifier */
     int           query_retries;                       /**< Number of times a interrupted query is retried */
     time_t        query_retry_timeout;                 /**< Timeout for query retries */
+    char*         local_address;                       /**< Local address to use when connecting */
 } MXS_CONFIG;
 
 /**

server/core/config.c

@@ -1401,6 +1401,10 @@ handle_global_item(const char *name, const char *value)
             MXS_FREE(v);
         }
     }
+    else if (strcmp(name, "local_address") == 0)
+    {
+        gateway.local_address = MXS_STRDUP_A(value);
+    }
     else
     {
         for (i = 0; lognames[i].name; i++)

server/core/utils.c

@@ -41,6 +41,7 @@
 #include <openssl/sha.h>
 
 #include <maxscale/alloc.h>
+#include <maxscale/config.h>
 #include <maxscale/dcb.h>
 #include <maxscale/log_manager.h>
 #include <maxscale/limits.h>
@@ -986,15 +987,47 @@ int open_network_socket(enum mxs_socket_type type, struct sockaddr_storage *addr
             memcpy(addr, ai->ai_addr, ai->ai_addrlen);
             set_port(addr, port);
 
+            freeaddrinfo(ai);
+
             if ((type == MXS_SOCKET_NETWORK && !configure_network_socket(so)) ||
                 (type == MXS_SOCKET_LISTENER && !configure_listener_socket(so)))
             {
                 close(so);
                 so = -1;
             }
-        }
+            else if (type == MXS_SOCKET_NETWORK)
+            {
+                MXS_CONFIG* config = config_get_global_options();
 
+                if (config->local_address)
+                {
+                    if ((rc = getaddrinfo(config->local_address, NULL, &hint, &ai)) == 0)
+                    {
+                        struct sockaddr_storage local_address = {};
+
+                        memcpy(&local_address, ai->ai_addr, ai->ai_addrlen);
                         freeaddrinfo(ai);
+
+                        if (bind(so, (struct sockaddr*)&local_address, sizeof(local_address)) == 0)
+                        {
+                            MXS_INFO("Bound connecting socket to \"%s\".", config->local_address);
+                        }
+                        else
+                        {
+                            MXS_ERROR("Could not bind connecting socket to local address \"%s\", "
+                                      "connecting to server using default local address: %s",
+                                      config->local_address, mxs_strerror(errno));
+                        }
+                    }
+                    else
+                    {
+                        MXS_ERROR("Could not get address information for local address \"%s\", "
+                                  "connecting to server using default local address: %s",
+                                  config->local_address, mxs_strerror(errno));
+                    }
+                }
+            }
+        }
     }
 
 #else