[at][sal] Add query and unregistered protocol family functions

components/net/sal_socket/SConscript

@@ -16,6 +16,9 @@ if GetDepend('SAL_USING_LWIP'):
 
 if GetDepend('SAL_USING_AT'):
     src += Glob('impl/af_inet_at.c')
+    
+if GetDepend('SAL_USING_LWIP') or GetDepend('SAL_USING_AT'):
+    CPPPATH += [cwd + '/impl']
 
 if GetDepend('SAL_USING_POSIX'):
     src += Glob('dfs_net/*.c')

components/net/sal_socket/impl/af_inet.h

@@ -0,0 +1,40 @@
+/*
+ * File      : af_inet.h
+ * This file is part of RT-Thread RTOS
+ * COPYRIGHT (C) 2006 - 2018, RT-Thread Development Team
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Change Logs:
+ * Date           Author       Notes
+ * 2018-08-25     ChenYong     First version
+ */
+
+#ifndef __AF_INET_H__
+#define __AF_INET_H__
+
+#include <rtthread.h>
+
+#ifdef SAL_USING_LWIP
+/* lwIP protocol family register */
+int lwip_inet_init(void);
+#endif
+
+#ifdef SAL_USING_AT
+/* AT protocol family register */
+int at_inet_init(void);
+#endif
+
+#endif /* __AF_INET_H__ */

components/net/sal_socket/impl/af_inet_at.c

@@ -26,6 +26,7 @@
 #include <sal.h>
 
 #include <at_socket.h>
+#include <af_inet.h>
 
 #ifdef SAL_USING_POSIX
 #include <dfs_poll.h>
@@ -107,6 +108,7 @@ static int at_create(struct sal_socket *socket, int type, int protocol)
 }
 
 static const struct proto_family at_inet_family_ops = {
+    "at",
     AF_AT,
     AF_INET,
     at_create,

components/net/sal_socket/impl/af_inet_lwip.c

@@ -34,6 +34,7 @@
 #endif
 
 #include <sal.h>
+#include <af_inet.h>
 
 #if LWIP_VERSION < 0x2000000
 #define SELWAIT_T int
@@ -284,6 +285,7 @@ static int inet_create(struct sal_socket *socket, int type, int protocol)
 }
 
 static const struct proto_family lwip_inet_family_ops = {
+    "lwip",
     AF_INET,
     AF_INET,
     inet_create,

components/net/sal_socket/include/sal.h

@@ -82,8 +82,9 @@ struct sal_socket
 
 struct proto_family
 {
-    int family;                        /* primary protocol families type*/
-    int sec_family;                    /* secondary protocol families type*/
+    char name[RT_NAME_MAX];
+    int family;                        /* primary protocol families type */
+    int sec_family;                    /* secondary protocol families type */
     int             (*create)(struct sal_socket *sal_socket, int type, int protocol);   /* register socket options */
 
     struct hostent* (*gethostbyname)  (const char *name);
@@ -92,10 +93,14 @@ struct proto_family
     int             (*getaddrinfo)    (const char *nodename, const char *servname, const struct addrinfo *hints, struct addrinfo **res);
 };
 
-/* SAL socket initialization */
+/* SAL(Socket Abstraction Layer) initialize */
 int sal_init(void);
 
-int sal_proto_family_register(const struct proto_family *pf);
 struct sal_socket *sal_get_socket(int sock);
 
+/* protocol family register and unregister operate */
+int sal_proto_family_register(const struct proto_family *pf);
+int sal_proto_family_unregister(const struct proto_family *pf);
+struct proto_family *sal_proto_family_find(const char *name);
+
 #endif /* SAL_H__ */

components/net/sal_socket/socket/net_netdb.c

@@ -38,6 +38,7 @@ int gethostbyname_r(const char *name, struct hostent *ret, char *buf,
 {
     return sal_gethostbyname_r(name, ret, buf, buflen, result, h_errnop);
 }
+RTM_EXPORT(gethostbyname_r);
 
 void freeaddrinfo(struct addrinfo *ai)
 {