Simplify network socket creation code

The socket creation code in mysql_backend.c wasn't MySQL specific and it
could be used for all non-blocking network connections. Thus, it makes
sense to move it to a common file where other protocol modules can use
it.

The address resolution code now uses `getaddrinfo` to resolve all
addresses instead of manually handling wildcard hosts. This allows the
same code to be used for all addresses.

include/maxscale/utils.h

@@ -44,10 +44,10 @@ void utils_end();
  * The configuration is passed as string in the `address|port` format.
  *
  * @param config        The bind address and port separated by a '|'
- * @param addr          The sockaddr_in6 in which the data is written
+ * @param addr          The struct sockaddr_storage in which the data is written
- * @return              1 on success, 0 on failure
+ * @return              True on success, false on failure
  */
-int  parse_bindconfig(const char *, struct sockaddr_in6 *, int *);
+bool parse_bindconfig(const char *config, struct sockaddr_storage *addr);
 
 
 /**
@@ -55,9 +55,11 @@ int  parse_bindconfig(const char *, struct sockaddr_in6 *, int *);
  *
  * @param dest Pointer to a struct sockaddr_storage where the configuration is stored
  * @param host The target host for which the socket is created
+ * @param port The target port on the host
  *
  * @return The opened socket or -1 on failure
- */int create_network_socket(struct sockaddr_storage *, char *);
+ */
+int open_network_socket(struct sockaddr_storage *dest, char *host, uint16_t port);
 
 int setnonblocking(int fd);
 char  *gw_strend(register const char *s);

server/core/dcb.c

@@ -3109,27 +3109,28 @@ dcb_listen(DCB *listener, const char *config, const char *protocol_name)
 static int
 dcb_listen_create_socket_inet(const char *config_bind)
 {
-    int listener_socket;
+    struct sockaddr_storage server_address = {};
-    struct sockaddr_in6 server_address = {};
-    int one = 1;
-    int sock_type = 0;
 
-    if (!parse_bindconfig(config_bind, &server_address, &sock_type))
+    if (!parse_bindconfig(config_bind, &server_address))
     {
         MXS_ERROR("Error in parse_bindconfig for [%s]", config_bind);
         return -1;
     }
 
+    /** TODO: Move everything before the `bind` call to utils.c */
+
     /** Create the TCP socket */
-    if ((listener_socket = socket(sock_type, SOCK_STREAM, 0)) < 0)
+    int listener_socket = socket(server_address.ss_family, SOCK_STREAM, 0);
+
+    if (listener_socket < 0)
     {
         char errbuf[MXS_STRERROR_BUFLEN];
-        MXS_ERROR("Can't create socket: %i, %s",
+        MXS_ERROR("Can't create socket: %d, %s", errno,
-                  errno,
                   strerror_r(errno, errbuf, sizeof(errbuf)));
         return -1;
     }
 
+    int one = 1;
     // socket options
     if (dcb_set_socket_option(listener_socket, SOL_SOCKET, SO_REUSEADDR, (char *) &one, sizeof(one)) != 0 ||
         dcb_set_socket_option(listener_socket, IPPROTO_TCP, TCP_NODELAY, (char *) &one, sizeof(one)) != 0)

server/core/utils.c

@@ -37,12 +37,13 @@
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/types.h>
-
+#include <netinet/tcp.h>
 #include <openssl/sha.h>
 
 #include <maxscale/alloc.h>
 #include <maxscale/dcb.h>
 #include <maxscale/log_manager.h>
+#include <maxscale/limits.h>
 #include <maxscale/pcre2.h>
 #include <maxscale/poll.h>
 #include <maxscale/random_jkiss.h>
@@ -895,42 +896,62 @@ void utils_end()
 
 SPINLOCK tmplock = SPINLOCK_INIT;
 
-int create_network_socket(struct sockaddr_storage *dest, char *host)
+static bool configure_socket(int so)
+{
+    int sndbufsize = MXS_BACKEND_SO_SNDBUF;
+    int rcvbufsize = MXS_BACKEND_SO_RCVBUF;
+    int one = 1;
+
+    if (setsockopt(so, SOL_SOCKET, SO_SNDBUF, &sndbufsize, sizeof(sndbufsize)) != 0 ||
+        setsockopt(so, SOL_SOCKET, SO_RCVBUF, &rcvbufsize, sizeof(rcvbufsize)) != 0 ||
+        setsockopt(so, IPPROTO_TCP, TCP_NODELAY, &one, sizeof(one)) != 0)
+    {
+        char errbuf[MXS_STRERROR_BUFLEN];
+        MXS_ERROR("Failed to set socket option: %d, %s.",
+                  errno, strerror_r(errno, errbuf, sizeof(errbuf)));
+        return false;
+    }
+
+    return setnonblocking(so) == 0;
+}
+
+static void set_port(struct sockaddr_storage *addr, uint16_t port)
+{
+    if (addr->ss_family == AF_INET)
+    {
+        struct sockaddr_in *ip = (struct sockaddr_in*)addr;
+        ip->sin_port = htons(port);
+    }
+    else if (addr->ss_family == AF_INET6)
+    {
+        struct sockaddr_in6 *ip = (struct sockaddr_in6*)addr;
+        ip->sin6_port = htons(port);
+    }
+    else
+    {
+        MXS_ERROR("Unknown address family: %d", (int)addr->ss_family);
+        ss_dassert(false);
+    }
+}
+
+int open_network_socket(struct sockaddr_storage *dest, char *host, uint16_t port)
 {
 #ifdef __USE_POSIX
     struct addrinfo *ai = NULL, hint = {};
     int so, rc;
     hint.ai_socktype = SOCK_STREAM;
     hint.ai_family = AF_UNSPEC;
+    hint.ai_flags = AI_ALL;
 
-    if (strcmp(host, "0.0.0.0") == 0 || strcmp(host, "::") == 0)
+    if ((rc = getaddrinfo(host, NULL, &hint, &ai)) != 0)
     {
-        /** All interfaces */
+        MXS_ERROR("Failed to obtain address for host %s, %s",
-        hint.ai_flags = AI_PASSIVE;
+                  host, gai_strerror(rc));
-        if ((rc = getaddrinfo(host, NULL, &hint, &ai)) != 0)
+        return -1;
-        {
-            MXS_ERROR("Failed to obtain address for host %s, %s",
-                      host,
-                      gai_strerror(rc));
-
-            return -1;
-        }
-    }
-    else
-    {
-        hint.ai_flags = AI_ALL;
-        if ((rc = getaddrinfo(host, NULL, &hint, &ai)) != 0)
-        {
-            MXS_ERROR("Failed to obtain address for host %s, %s",
-                      host,
-                      gai_strerror(rc));
-
-            return -1;
-        }
     }
 
-    /* take the first one */
+    /* Take the first one */
-    if (ai != NULL)
+    if (ai)
     {
         so = socket(ai->ai_family, SOCK_STREAM, 0);
 
@@ -943,23 +964,33 @@ int create_network_socket(struct sockaddr_storage *dest, char *host)
         else
         {
             memcpy(dest, ai->ai_addr, ai->ai_addrlen);
-            freeaddrinfo(ai);
+            set_port(dest, port);
+
+            if (!configure_socket(so))
+            {
+                close(so);
+                so = -1;
+            }
         }
+
+        freeaddrinfo(ai);
     }
+
 #else
 #error Only the POSIX networking interface is supported
 #endif
+
     return so;
 }
 
-int parse_bindconfig(const char *config, struct sockaddr_in6 *addr, int *sock_type)
+bool parse_bindconfig(const char *config, struct sockaddr_storage *addr)
 {
     char buf[strlen(config) + 1];
     strcpy(buf, config);
-    *sock_type = strchr(buf, '.')  ? AF_INET : AF_INET6;
 
     char *port = strrchr(buf, '|');
     short pnum;
+
     if (port)
     {
         *port = 0;
@@ -968,35 +999,35 @@ int parse_bindconfig(const char *config, struct sockaddr_in6 *addr, int *sock_ty
     }
     else
     {
+        ss_dassert(false);
         return 0;
     }
 
-    if (!strcmp(buf, "0.0.0.0") || !strcmp(buf, "::"))
+    struct addrinfo *ai = NULL, hint = {};
+    hint.ai_flags = AI_ALL;
+    hint.ai_family = AF_UNSPEC;
+    int rc = getaddrinfo(buf, NULL, &hint, &ai);
+
+    if (rc == 0)
     {
-        *sock_type = AF_INET6;
+        if (ai)
-        addr->sin6_addr = in6addr_any;
+        {
+            memcpy(addr, ai->ai_addr, ai->ai_addrlen);
+            set_port(addr, pnum);
+            freeaddrinfo(ai);
+        }
+        else
+        {
+            MXS_ERROR("Failed to find valid network address for '%s'.", config);
+            rc = -1;
+        }
     }
     else
     {
-        if (inet_pton(*sock_type, buf, &addr->sin6_addr) < 1)
+        MXS_ERROR("Failed to resolve network address for '%s': %s", config, gai_strerror(rc));
-        {
-            struct hostent *hp = gethostbyname(buf);
-
-            if (hp)
-            {
-                inet_pton(*sock_type, hp->h_addr_list[0], &addr->sin6_addr);
-            }
-            else
-            {
-                MXS_ERROR("Failed to lookup host '%s'.", buf);
-                return 0;
-            }
-        }
     }
 
-    addr->sin6_family = *sock_type;
+    return rc == 0;
-    addr->sin6_port = htons(pnum);
-    return 1;
 }
 
 /**

server/modules/protocol/MySQL/MySQLBackend/mysql_backend.c

@@ -18,7 +18,6 @@
 #include <maxscale/log_manager.h>
 #include <maxscale/modutil.h>
 #include <maxscale/utils.h>
-#include <netinet/tcp.h>
 #include <mysqld_error.h>
 #include <maxscale/alloc.h>
 #include <maxscale/modinfo.h>
@@ -275,82 +274,16 @@ static int gw_do_connect_to_backend(char *host, int port, int *fd)
 {
     struct sockaddr_storage serv_addr = {};
     int rv = -1;
-    int bufsize;
 
     /* prepare for connect */
-    int so = create_network_socket(&serv_addr, host);
+    int so = open_network_socket(&serv_addr, host, port);
 
     if (so < 0)
     {
-        char errbuf[MXS_STRERROR_BUFLEN];
         MXS_ERROR("Establishing connection to backend server %s:%d failed.", host, port);
         return rv;
     }
 
-    /** Configure the destination port */
-    if (serv_addr.ss_family == AF_INET)
-    {
-        struct sockaddr_in *ip = (struct sockaddr_in*)&serv_addr;
-        ip->sin_port = htons(port);
-    }
-    else
-    {
-        ss_dassert(serv_addr.ss_family == AF_INET6);
-        struct sockaddr_in6 *ip = (struct sockaddr_in6*)&serv_addr;
-        ip->sin6_port = htons(port);
-    }
-
-    bufsize = MXS_BACKEND_SO_SNDBUF;
-
-    if (setsockopt(so, SOL_SOCKET, SO_SNDBUF, &bufsize, sizeof(bufsize)) != 0)
-    {
-        char errbuf[MXS_STRERROR_BUFLEN];
-        MXS_ERROR("Failed to set socket options "
-                  "%s:%d failed.\n\t\t             Socket configuration failed "
-                  "due %d, %s.",
-                  host,
-                  port,
-                  errno,
-                  strerror_r(errno, errbuf, sizeof(errbuf)));
-        /** Close socket */
-        close_socket(so);
-        return rv;
-    }
-    bufsize = MXS_BACKEND_SO_RCVBUF;
-
-    if (setsockopt(so, SOL_SOCKET, SO_RCVBUF, &bufsize, sizeof(bufsize)) != 0)
-    {
-        char errbuf[MXS_STRERROR_BUFLEN];
-        MXS_ERROR("Failed to set socket options "
-                  "%s:%d failed.\n\t\t             Socket configuration failed "
-                  "due %d, %s.",
-                  host,
-                  port,
-                  errno,
-                  strerror_r(errno, errbuf, sizeof(errbuf)));
-        /** Close socket */
-        close_socket(so);
-        return rv;
-    }
-
-    int one = 1;
-    if (setsockopt(so, IPPROTO_TCP, TCP_NODELAY, &one, sizeof(one)) != 0)
-    {
-        char errbuf[MXS_STRERROR_BUFLEN];
-        MXS_ERROR("Failed to set socket options "
-                  "%s:%d failed.\n\t\t             Socket configuration failed "
-                  "due %d, %s.",
-                  host,
-                  port,
-                  errno,
-                  strerror_r(errno, errbuf, sizeof(errbuf)));
-        /** Close socket */
-        close_socket(so);
-        return rv;
-    }
-
-    /* set socket to as non-blocking here */
-    setnonblocking(so);
     rv = connect(so, (struct sockaddr *)&serv_addr, sizeof(serv_addr));
 
     if (rv != 0)
@@ -365,7 +298,7 @@ static int gw_do_connect_to_backend(char *host, int port, int *fd)
             MXS_ERROR("Failed to connect backend server %s:%d due to: %d, %s.",
                       host, port, errno, strerror_r(errno, errbuf, sizeof(errbuf)));
             /** Close socket */
-            close_socket(so);
+            close(so);
             return rv;
         }
     }
@@ -1817,21 +1750,6 @@ static bool sescmd_response_complete(DCB* dcb)
     return succp;
 }
 
-static void inline
-close_socket(int sock)
-{
-    /*< Close newly created socket. */
-    if (close(sock) != 0)
-    {
-        char errbuf[MXS_STRERROR_BUFLEN];
-        MXS_ERROR("Failed to close socket %d due %d, %s.",
-                  sock,
-                  errno,
-                  strerror_r(errno, errbuf, sizeof(errbuf)));
-    }
-
-}
-
 /**
  * Create COM_CHANGE_USER packet and store it to GWBUF
  *