Merge pull request #1737 from chenyong111/master

Add query and unregistered protocol family functions，format code

15 files changed, 261 insertions, 72 deletions

diff --git a/components/net/at/at_socket/at_socket.c b/components/net/at/at_socket/at_socket.c
index 3580df957b..a95c7aec53 100644
--- a/components/net/at/at_socket/at_socket.c
+++ b/components/net/at/at_socket/at_socket.c
@@ -36,10 +36,9 @@
 
 #ifdef DBG_SECTION_NAME
 #undef DBG_SECTION_NAME
-#define DBG_SECTION_NAME     "[AT_SOC] "
+#define DBG_SECTION_NAME     "AT_SOC"
 #endif
 
-
 #define HTONS_PORT(x) ((((x) & 0x00ffUL) << 8) | (((x) & 0xff00UL) >> 8))
 #define NIPQUAD(addr) \
         ((unsigned char *)&addr)[0], \
@@ -89,7 +88,7 @@ static size_t at_recvpkt_put(rt_slist_t *rlist, const char *ptr, size_t length)
     at_recv_pkt_t pkt;
 
     pkt = (at_recv_pkt_t) rt_calloc(1, sizeof(struct at_recv_pkt));
-    if (!pkt)
+    if (pkt == RT_NULL)
     {
         LOG_E("No memory for receive packet table!");
         return 0;
@@ -340,7 +339,7 @@ int at_socket(int domain, int type, int protocol)
 
     /* allocate and initialize a new AT socket */
     sock = alloc_socket();
-    if(!sock)
+    if(sock == RT_NULL)
     {
         LOG_E("Allocate a new AT socket failed!");
         return RT_NULL;
@@ -381,14 +380,16 @@ int at_closesocket(int socket)
     struct at_socket *sock;
     enum at_socket_state last_state;
 
-    if (!at_dev_ops)
+    if (at_dev_ops == RT_NULL)
     {
-        LOG_E("Please register AT device socket options first!");
         return -1;
     }
 
-    if ((sock = at_get_socket(socket)) == RT_NULL)
+    sock = at_get_socket(socket);
+    if (sock == RT_NULL)
+    {
         return -1;
+    }
 
     last_state = sock->state;
 
@@ -410,14 +411,16 @@ int at_shutdown(int socket, int how)
 {
     struct at_socket *sock;
 
-    if (!at_dev_ops)
+    if (at_dev_ops == RT_NULL)
     {
-        LOG_E("Please register AT device socket options first!");
         return -1;
     }
 
-    if ((sock = at_get_socket(socket)) == RT_NULL)
+    sock = at_get_socket(socket);
+    if (sock == RT_NULL)
+    {
         return -1;
+    }
 
     if (sock->state == AT_SOCKET_CONNECT)
     {
@@ -434,7 +437,9 @@ int at_bind(int socket, const struct sockaddr *name, socklen_t namelen)
 {
 
     if (at_get_socket(socket) == RT_NULL)
+    {
         return -1;
+    }
 
     return 0;
 }
@@ -470,7 +475,8 @@ static void at_recv_notice_cb(int socket, at_socket_evt_t event, const char *buf
     RT_ASSERT(bfsz);
     RT_ASSERT(event == AT_SOCKET_EVT_RECV);
 
-    if ((sock = at_get_socket(socket)) == RT_NULL)
+    sock = at_get_socket(socket);
+    if (sock == RT_NULL)
         return ;
 
     /* put receive buffer to receiver packet list */
@@ -506,14 +512,13 @@ int at_connect(int socket, const struct sockaddr *name, socklen_t namelen)
     char ipstr[16] = { 0 };
     int result = 0;
 
-    if (!at_dev_ops)
+    if (at_dev_ops == RT_NULL)
     {
-        LOG_E("Please register AT device socket options first!");
         return -1;
     }
 
     sock = at_get_socket(socket);
-    if (!sock)
+    if (sock == RT_NULL)
     {
         result = -1;
         goto __exit;
@@ -560,21 +565,19 @@ int at_recvfrom(int socket, void *mem, size_t len, int flags, struct sockaddr *f
     int result = 0;
     size_t recv_len = 0;
 
-    if (!mem || len == 0)
+    if (mem == RT_NULL || len == 0)
     {
         LOG_E("AT recvfrom input data or length error!");
-        result = -1;
-        goto __exit;
+        return -1;
     }
 
-    if (!at_dev_ops)
+    if (at_dev_ops == RT_NULL)
     {
-        LOG_E("Please register AT device socket options first!");
         return -1;
     }
 
     sock = at_get_socket(socket);
-    if (!sock)
+    if (sock == RT_NULL)
     {
         result = -1;
         goto __exit;
@@ -686,14 +689,13 @@ int at_sendto(int socket, const void *data, size_t size, int flags, const struct
     struct at_socket *sock;
     int len, result = 0;
 
-    if (!at_dev_ops)
+    if (at_dev_ops == RT_NULL)
     {
-        LOG_E("Please register AT device socket options first!");
         result = -1;
         goto __exit;
     }
 
-    if (!data || size == 0)
+    if (data == RT_NULL || size == 0)
     {
         LOG_E("AT sendto input data or size error!");
         result = -1;
@@ -701,7 +703,7 @@ int at_sendto(int socket, const void *data, size_t size, int flags, const struct
     }
 
     sock = at_get_socket(socket);
-    if (!sock)
+    if (sock == RT_NULL)
     {
         result = -1;
         goto __exit;
@@ -780,14 +782,14 @@ int at_getsockopt(int socket, int level, int optname, void *optval, socklen_t *o
     struct at_socket *sock;
     int32_t timeout;
 
-    if (!optval || !optlen)
+    if (optval == RT_NULL || optlen == RT_NULL)
     {
         LOG_E("AT getsocketopt input option value or option length error!");
         return -1;
     }
 
     sock = at_get_socket(socket);
-    if (!sock)
+    if (sock == RT_NULL)
     {
         return -1;
     }
@@ -827,14 +829,14 @@ int at_setsockopt(int socket, int level, int optname, const void *optval, sockle
 {
     struct at_socket *sock;
 
-    if (!optval)
+    if (optval == RT_NULL)
     {
         LOG_E("AT setsockopt input option value error!");
         return -1;
     }
 
     sock = at_get_socket(socket);
-    if (!sock)
+    if (sock == RT_NULL)
     {
         return -1;
     }
@@ -923,15 +925,14 @@ struct hostent *at_gethostbyname(const char *name)
     static char s_hostname[DNS_MAX_NAME_LENGTH + 1];
     size_t idx = 0;
 
-    if (!name)
+    if (name == RT_NULL)
     {
         LOG_E("AT gethostbyname input name error!");
         return RT_NULL;
     }
 
-    if (!at_dev_ops)
+    if (at_dev_ops == RT_NULL)
     {
-        LOG_E("Please register AT device socket options first!");
         return RT_NULL;
     }
 
@@ -983,12 +984,13 @@ int at_getaddrinfo(const char *nodename, const char *servname,
     {
         return EAI_FAIL;
     }
-    if (!at_dev_ops)
+    *res = RT_NULL;
+
+    if (at_dev_ops == RT_NULL)
     {
-        LOG_E("Please register AT device socket options first!");
         return EAI_FAIL;
     }
-    *res = RT_NULL;
+
     if ((nodename == RT_NULL) && (servname == RT_NULL))
     {
         return EAI_NONAME;
@@ -1085,10 +1087,10 @@ int at_getaddrinfo(const char *nodename, const char *servname,
     struct sockaddr_in *sa4 = (struct sockaddr_in *) sa;
     /* set up sockaddr */
     sa4->sin_addr.s_addr = addr.u_addr.ip4.addr;
-    sa4->sin_family = AF_AT;
+    sa4->sin_family = AF_INET;
     sa4->sin_len = sizeof(struct sockaddr_in);
     sa4->sin_port = htons((u16_t )port_nr);
-    ai->ai_family = AF_AT;
+    ai->ai_family = AF_INET;
 
     /* set up addrinfo */
     if (hints != RT_NULL)
@@ -1114,9 +1116,13 @@ int at_getaddrinfo(const char *nodename, const char *servname,
 
 void at_freeaddrinfo(struct addrinfo *ai)
 {
-    if (ai != RT_NULL)
+    struct addrinfo *next;
+
+    while (ai != NULL)
     {
+        next = ai->ai_next;
         rt_free(ai);
+        ai = next;
     }
 }
 
diff --git a/components/net/at/at_socket/at_socket.h b/components/net/at/at_socket/at_socket.h
index 612078522d..7d9ce91f39 100644
--- a/components/net/at/at_socket/at_socket.h
+++ b/components/net/at/at_socket/at_socket.h
@@ -32,6 +32,10 @@
 #include <netdb.h>
 #include <sys/socket.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #ifndef AT_SOCKET_RECV_BFSZ
 #define AT_SOCKET_RECV_BFSZ            512
 #endif
@@ -144,7 +148,7 @@ void at_scoket_device_register(const struct at_device_ops *ops);
 #ifndef RT_USING_SAL
 
 #define socket(domain, type, protocol)                      at_socket(domain, type, protocol)
-#define closescoket(socket)                                 at_closesocket(socket)
+#define closesocket(socket)                                 at_closesocket(socket)
 #define shutdown(socket, how)                               at_shutdown(socket, how)
 #define bind(socket, name, namelen)                         at_bind(socket, name, namelen)
 #define connect(socket, name, namelen)                      at_connect(socket, name, namelen)
@@ -160,4 +164,8 @@ void at_scoket_device_register(const struct at_device_ops *ops);
 
 #endif /* RT_USING_SAL */
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* AT_SOCKET_H__ */
diff --git a/components/net/at/include/at.h b/components/net/at/include/at.h
index d0040f86cf..1ef0388a65 100644
--- a/components/net/at/include/at.h
+++ b/components/net/at/include/at.h
@@ -27,6 +27,9 @@
 
 #include <rtthread.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
 #define AT_SW_VERSION                  "0.3.0"
 
 #define DBG_ENABLE
@@ -251,4 +254,8 @@ void at_port_reset(void);
 void at_port_factory_reset(void);
 #endif
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* __AT_H__ */
diff --git a/components/net/sal_socket/SConscript b/components/net/sal_socket/SConscript
index 76becca09f..3dcb5c3fe4 100644
--- a/components/net/sal_socket/SConscript
+++ b/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')
diff --git a/components/net/sal_socket/impl/af_inet.h b/components/net/sal_socket/impl/af_inet.h
new file mode 100644
index 0000000000..8d6be25eaa
--- /dev/null
+++ b/components/net/sal_socket/impl/af_inet.h
@@ -0,0 +1,48 @@
+/*
+ * 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 __cplusplus
+extern "C" {
+#endif
+
+#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
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __AF_INET_H__ */
diff --git a/components/net/sal_socket/impl/af_inet_at.c b/components/net/sal_socket/impl/af_inet_at.c
index 8ddb236e84..3337af4194 100644
--- a/components/net/sal_socket/impl/af_inet_at.c
+++ b/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,
diff --git a/components/net/sal_socket/impl/af_inet_lwip.c b/components/net/sal_socket/impl/af_inet_lwip.c
index deb9239bf4..c45e39e39e 100644
--- a/components/net/sal_socket/impl/af_inet_lwip.c
+++ b/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,
diff --git a/components/net/sal_socket/include/dfs_net/dfs_net.h b/components/net/sal_socket/include/dfs_net/dfs_net.h
index 2a21fe3858..242d3c5334 100644
--- a/components/net/sal_socket/include/dfs_net/dfs_net.h
+++ b/components/net/sal_socket/include/dfs_net/dfs_net.h
@@ -26,12 +26,12 @@
 #ifndef DFS_NET_H__
 #define DFS_NET_H__
 
+#include <dfs_file.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-#include <dfs_file.h>
-
 const struct dfs_file_ops* dfs_net_get_fops(void);
 int dfs_net_getsocket(int fd);
 
diff --git a/components/net/sal_socket/include/sal.h b/components/net/sal_socket/include/sal.h
index 8a9dd61b67..62ffaa303e 100644
--- a/components/net/sal_socket/include/sal.h
+++ b/components/net/sal_socket/include/sal.h
@@ -28,6 +28,10 @@
 #include <dfs_file.h>
 #include <rtdevice.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #if !defined(socklen_t) && !defined(SOCKLEN_T_DEFINED)
 typedef uint32_t socklen_t;
 #endif
@@ -82,8 +86,9 @@ 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 +97,18 @@ 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);
+
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* SAL_H__ */
diff --git a/components/net/sal_socket/include/sal_ipaddr.h b/components/net/sal_socket/include/sal_ipaddr.h
index 814d1d16e9..c40fc18374 100644
--- a/components/net/sal_socket/include/sal_ipaddr.h
+++ b/components/net/sal_socket/include/sal_ipaddr.h
@@ -26,6 +26,10 @@
 
 #include "sal_type.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /** IPv4 only: set the IP address given as an u32_t */
 #define ip4_addr_set_u32(dest_ipaddr, src_u32) ((dest_ipaddr)->addr = (src_u32))
 /** IPv4 only: get the IP address as an u32_t */
diff --git a/components/net/sal_socket/include/sal_netdb.h b/components/net/sal_socket/include/sal_netdb.h
index 12f7abe6b7..0a31f26fae 100644
--- a/components/net/sal_socket/include/sal_netdb.h
+++ b/components/net/sal_socket/include/sal_netdb.h
@@ -26,6 +26,10 @@
 
 #include <sal_socket.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #define EAI_NONAME      200
 #define EAI_SERVICE     201
 #define EAI_FAIL        202
@@ -88,4 +92,8 @@ int sal_getaddrinfo(const char *nodename,
        const struct addrinfo *hints,
        struct addrinfo **res);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* SAL_NETDB_H__ */
diff --git a/components/net/sal_socket/include/sal_socket.h b/components/net/sal_socket/include/sal_socket.h
index 872fd5ca95..477112392c 100644
--- a/components/net/sal_socket/include/sal_socket.h
+++ b/components/net/sal_socket/include/sal_socket.h
@@ -27,6 +27,10 @@
 
 #include "sal_ipaddr.h"
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #if !defined(socklen_t) && !defined(SOCKLEN_T_DEFINED)
 typedef uint32_t socklen_t;
 #endif
@@ -175,4 +179,8 @@ int sal_socket(int domain, int type, int protocol);
 int sal_closesocket(int socket);
 int sal_ioctlsocket(int socket, long cmd, void *arg);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* SAL_SOCKET_H__ */
diff --git a/components/net/sal_socket/include/sal_type.h b/components/net/sal_socket/include/sal_type.h
index 0446d5f4e1..907b3d02b4 100644
--- a/components/net/sal_socket/include/sal_type.h
+++ b/components/net/sal_socket/include/sal_type.h
@@ -28,6 +28,10 @@
 #include <stdlib.h>
 #include <stdint.h>
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef int8_t    err_t;
 typedef uint8_t   u8_t;
 typedef int8_t    s8_t;
@@ -37,4 +41,8 @@ typedef uint32_t  u32_t;
 typedef int32_t   s32_t;
 typedef uintptr_t mem_ptr_t;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* SAL_TYPE_H__ */
diff --git a/components/net/sal_socket/socket/net_netdb.c b/components/net/sal_socket/socket/net_netdb.c
index 5acab36403..1f10afe337 100644
--- a/components/net/sal_socket/socket/net_netdb.c
+++ b/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)
 {
diff --git a/components/net/sal_socket/src/sal_socket.c b/components/net/sal_socket/src/sal_socket.c
index 71aaa2c658..7b6683a69c 100644
--- a/components/net/sal_socket/src/sal_socket.c
+++ b/components/net/sal_socket/src/sal_socket.c
@@ -50,7 +50,7 @@ static struct rt_mutex sal_core_lock;
 static rt_bool_t init_ok = RT_FALSE;
 
 /**
- * SAL (Socket Abstraction Layer) initialization.
+ * SAL (Socket Abstraction Layer) initialize.
  *
  * @return result
  *         >= 0: initialize success
@@ -64,7 +64,7 @@ int sal_init(void)
     }
 
     /* clean sal socket table */
-    memset(&socket_table, 0, sizeof(socket_table));
+    rt_memset(&socket_table, 0, sizeof(socket_table));
     /* create sal socket lock */
     rt_mutex_init(&sal_core_lock, "sal_lock", RT_IPC_FLAG_FIFO);
 
@@ -76,12 +76,12 @@ int sal_init(void)
 INIT_COMPONENT_EXPORT(sal_init);
 
 /**
- *  this function will register the current protocol family to the global array of protocol families.
+ * This function will register protocol family to the global array of protocol families.
  *
- * @param pf protocol families structure
+ * @param pf protocol family object
  *
- * @return 0 : protocol families structure index
- *        -1 : the global array of available protocol families is full
+ * @return >=0 : protocol family object index
+ *          -1 : the global array of available protocol families is full
  */
 int sal_proto_family_register(const struct proto_family *pf)
 {
@@ -91,6 +91,18 @@ int sal_proto_family_register(const struct proto_family *pf)
     /* disable interrupt */
     level = rt_hw_interrupt_disable();
 
+    /* check protocol family is already registered */
+    for(idx = 0; idx < SAL_PROTO_FAMILIES_NUM; idx++)
+    {
+        if(rt_strcmp(proto_families[idx].name, pf->name) == 0)
+        {
+            /* enable interrupt */
+            rt_hw_interrupt_enable(level);
+            LOG_E("%s protocol family is already registered!", pf->name);
+            return -1;
+        }
+    }
+
     /* find an empty protocol family entry */
     for(idx = 0; idx < SAL_PROTO_FAMILIES_NUM && proto_families[idx].create; idx++);
 
@@ -99,10 +111,10 @@ int sal_proto_family_register(const struct proto_family *pf)
     {
         /* enable interrupt */
         rt_hw_interrupt_enable(level);
-
         return -1;
     }
 
+    rt_strncpy(proto_families[idx].name, pf->name, rt_strlen(pf->name));
     proto_families[idx].family = pf->family;
     proto_families[idx].sec_family = pf->sec_family;
     proto_families[idx].create = pf->create;
@@ -119,11 +131,62 @@ int sal_proto_family_register(const struct proto_family *pf)
 }
 
 /**
- *  this function will get socket structure by sal socket descriptor
+ * This function removes a previously registered protocol family object.
+ *
+ * @param pf protocol family object
+ *
+ * @return >=0 : unregister protocol family index
+ *          -1 : unregister failed
+ */
+int sal_proto_family_unregister(const struct proto_family *pf)
+{
+    int idx = 0;
+
+    RT_ASSERT(pf != RT_NULL);
+
+    for(idx = 0; idx < SAL_PROTO_FAMILIES_NUM; idx++)
+    {
+        if(rt_strcmp(proto_families[idx].name, pf->name) == 0)
+        {
+            rt_memset(&proto_families[idx], 0x00, sizeof(struct proto_family));
+
+            return idx;
+        }
+    }
+
+    return -1;
+}
+
+/**
+ * This function will get protocol family by name.
+ *
+ * @param name protocol family name
+ *
+ * @return protocol family object
+ */
+struct proto_family *sal_proto_family_find(const char *name)
+{
+    int idx = 0;
+
+    RT_ASSERT(name != RT_NULL);
+
+    for (idx = 0; idx < SAL_PROTO_FAMILIES_NUM; idx++)
+    {
+        if (rt_strcmp(proto_families[idx].name, name) == 0)
+        {
+            return &proto_families[idx];
+        }
+    }
+
+    return RT_NULL;
+}
+
+/**
+ * This function will get sal socket object by sal socket descriptor.
  *
  * @param socket sal socket index
  *
- * @return socket structure of the current sal socket index
+ * @return sal socket object of the current sal socket index
  */
 struct sal_socket *sal_get_socket(int socket)
 {
@@ -145,7 +208,7 @@ struct sal_socket *sal_get_socket(int socket)
 }
 
 /**
- * this function will lock sal socket.
+ * This function will lock sal socket.
  *
  * @note please don't invoke it on ISR.
  */
@@ -161,7 +224,7 @@ static void sal_lock(void)
 }
 
 /**
- * this function will lock sal socket.
+ * This function will lock sal socket.
  *
  * @note please don't invoke it on ISR.
  */
@@ -171,7 +234,7 @@ static void sal_unlock(void)
 }
 
 /**
- *  this function will get protocol family structure by family type
+ * This function will get protocol family structure by family type
  *
  * @param family  protocol family
  *
@@ -201,17 +264,17 @@ static struct proto_family *get_proto_family(int family)
 }
 
 /**
- *  this function will initialize socket structure and set socket options
+ * This function will initialize sal socket object and set socket options
  *
  * @param family    protocol family
  * @param type      socket type
  * @param protocol  transfer Protocol
- * @param res       socket structure address
+ * @param res       sal socket object address
  *
  * @return  0 : socket initialize success
  *         -1 : input the wrong family
  *         -2 : input the wrong socket type
- *         -3 : get protocol family structure failed
+ *         -3 : get protocol family object failed
  *         -4 : set socket options failed
  */
 static int socket_init(int family, int type, int protocol, struct sal_socket **res)
@@ -234,7 +297,7 @@ static int socket_init(int family, int type, int protocol, struct sal_socket **r
     sock->type = type;
     sock->protocol = protocol;
 
-    /* get socket protocol family structure */
+    /* get socket protocol family object */
     if ((pf = get_proto_family(family)) == RT_NULL)
     {
         return -3;
@@ -301,11 +364,6 @@ __result:
 
 }
 
-/**
- * this function will return a empty sal socket structure address
- *
- * @return sal socket structure address
- */
 static int socket_new(void)
 {
     struct sal_socket *sock;
@@ -415,7 +473,7 @@ int sal_shutdown(int socket, int how)
 
     if (sock->ops->shutdown((int) sock->user_data, how) == 0)
     {
-        memset(sock, 0x00, sizeof(struct sal_socket));
+        rt_memset(sock, 0x00, sizeof(struct sal_socket));
         return 0;
     }
 
@@ -622,7 +680,7 @@ int sal_closesocket(int socket)
 
     if (sock->ops->closesocket((int) sock->user_data) == 0)
     {
-        memset(sock, 0x00, sizeof(struct sal_socket));
+        rt_memset(sock, 0x00, sizeof(struct sal_socket));
         return 0;
     }
 
@@ -669,12 +727,17 @@ int sal_poll(struct dfs_fd *file, struct rt_pollreq *req)
 struct hostent *sal_gethostbyname(const char *name)
 {
     int i;
+    struct hostent *hst;
 
     for (i = 0; i < SAL_PROTO_FAMILIES_NUM; ++i)
     {
         if (proto_families[i].gethostbyname)
         {
-            return proto_families[i].gethostbyname(name);
+            hst = proto_families[i].gethostbyname(name);
+            if (hst != RT_NULL)
+            {
+                return hst;
+            }
         }
     }
 
@@ -684,13 +747,17 @@ struct hostent *sal_gethostbyname(const char *name)
 int sal_gethostbyname_r(const char *name, struct hostent *ret, char *buf,
                 size_t buflen, struct hostent **result, int *h_errnop)
 {
-    int i;
+    int i, res;
 
     for (i = 0; i < SAL_PROTO_FAMILIES_NUM; ++i)
     {
         if (proto_families[i].gethostbyname_r)
         {
-            return proto_families[i].gethostbyname_r(name, ret, buf, buflen, result, h_errnop);
+            res = proto_families[i].gethostbyname_r(name, ret, buf, buflen, result, h_errnop);
+            if (res == 0)
+            {
+                return res;
+            }
         }
     }
 
@@ -716,13 +783,17 @@ int sal_getaddrinfo(const char *nodename,
        const struct addrinfo *hints,
        struct addrinfo **res)
 {
-    int i;
+    int i, ret;
 
     for (i = 0; i < SAL_PROTO_FAMILIES_NUM; ++i)
     {
         if (proto_families[i].getaddrinfo)
         {
-            return proto_families[i].getaddrinfo(nodename, servname, hints, res);
+            ret = proto_families[i].getaddrinfo(nodename, servname, hints, res);
+            if (ret == 0)
+            {
+                return ret;
+            }
         }
     }