Cellular: Check IP version of send to address

Author: Mirela Chirica

features/cellular/framework/AT/AT_CellularStack.cpp

@@ -23,7 +23,7 @@
 using namespace mbed_cellular_util;
 using namespace mbed;
 
-AT_CellularStack::AT_CellularStack(ATHandler &at, int cid, nsapi_ip_stack_t stack_type) : AT_CellularBase(at), _socket(NULL), _socket_count(0), _cid(cid), _stack_type(stack_type)
+AT_CellularStack::AT_CellularStack(ATHandler &at, int cid, nsapi_ip_stack_t stack_type) : AT_CellularBase(at), _socket(NULL), _socket_count(0), _cid(cid), _stack_type(stack_type), _ip_ver_sendto(NSAPI_UNSPEC)
 {
     memset(_ip, 0, PDP_IPV6_SIZE);
 }
@@ -272,6 +272,13 @@ nsapi_size_or_error_t AT_CellularStack::socket_sendto(nsapi_socket_t handle, con
     nsapi_size_or_error_t ret_val = NSAPI_ERROR_OK;
 
     if (socket->id == -1) {
+
+        /* Check that stack type supports sendto address type*/
+        if (!is_addr_stack_compatible(addr)) {
+            return NSAPI_ERROR_PARAMETER;
+        }
+
+        _ip_ver_sendto = addr.get_ip_version();
         _at.lock();
 
         ret_val = create_socket_impl(socket);
@@ -283,9 +290,9 @@ nsapi_size_or_error_t AT_CellularStack::socket_sendto(nsapi_socket_t handle, con
         }
     }
 
-    /* Check parameters */
-    if (addr.get_ip_version() == NSAPI_UNSPEC) {
-        return NSAPI_ERROR_DEVICE_ERROR;
+    /* Check parameters - sendto address is valid and stack type supports sending to that address type*/
+    if (!is_addr_stack_compatible(addr)) {
+        return NSAPI_ERROR_PARAMETER;
     }
 
     _at.lock();
@@ -393,3 +400,14 @@ AT_CellularStack::CellularSocket *AT_CellularStack::find_socket(int sock_id)
     }
     return sock;
 }
+
+bool AT_CellularStack::is_addr_stack_compatible(const SocketAddress &addr)
+{
+    if ((addr.get_ip_version() == NSAPI_UNSPEC) ||
+            (addr.get_ip_version() == NSAPI_IPv4 && _stack_type == IPV6_STACK) ||
+            (addr.get_ip_version() == NSAPI_IPv6 && _stack_type == IPV4_STACK)) {
+        return false;
+    }
+    return true;
+}
+

features/cellular/framework/AT/AT_CellularStack.h

@@ -191,6 +191,11 @@ class AT_CellularStack : public NetworkStack, public AT_CellularBase {
      */
     int find_socket_index(nsapi_socket_t handle);
 
+    /**
+     *  Checks if send to address is valid and if current stack type supports sending to that address type
+     */
+    bool is_addr_stack_compatible(const SocketAddress &addr);
+
     // socket container
     CellularSocket **_socket;
 
@@ -206,6 +211,9 @@ class AT_CellularStack : public NetworkStack, public AT_CellularBase {
     // stack type - initialised as PDP type and set accordingly after CGPADDR checked
     nsapi_ip_stack_t _stack_type;
 
+    // IP version of send to address
+    nsapi_version_t _ip_ver_sendto;
+
 private:
 
     int get_socket_index_by_port(uint16_t port);

features/cellular/framework/targets/QUECTEL/BG96/QUECTEL_BG96_CellularStack.cpp

@@ -212,7 +212,7 @@ nsapi_error_t QUECTEL_BG96_CellularStack::create_socket_impl(CellularSocket *soc
 
     if (socket->proto == NSAPI_UDP && !socket->connected) {
         _at.at_cmd_discard("+QIOPEN", "=", "%d%d%s%s%d%d%d", _cid, request_connect_id, "UDP SERVICE",
-                           (_stack_type == IPV4_STACK) ? "127.0.0.1" : "0:0:0:0:0:0:0:1",
+                           (_ip_ver_sendto == NSAPI_IPv4) ? "127.0.0.1" : "0:0:0:0:0:0:0:1",
                            remote_port, socket->localAddress.get_port(), 0);
 
         handle_open_socket_response(modem_connect_id, err);
@@ -225,7 +225,7 @@ nsapi_error_t QUECTEL_BG96_CellularStack::create_socket_impl(CellularSocket *soc
             socket_close_impl(modem_connect_id);
 
             _at.at_cmd_discard("+QIOPEN", "=", "%d%d%s%s%d%d%d", _cid, request_connect_id, "UDP SERVICE",
-                               (_stack_type == IPV4_STACK) ? "127.0.0.1" : "0:0:0:0:0:0:0:1",
+                               (_ip_ver_sendto == NSAPI_IPv4) ? "127.0.0.1" : "0:0:0:0:0:0:0:1",
                                remote_port, socket->localAddress.get_port(), 0);
 
             handle_open_socket_response(modem_connect_id, err);
@@ -273,6 +273,12 @@ nsapi_size_or_error_t QUECTEL_BG96_CellularStack::socket_sendto_impl(CellularSoc
         return NSAPI_ERROR_PARAMETER;
     }
 
+    if (_ip_ver_sendto != address.get_ip_version()) {
+        _ip_ver_sendto =  address.get_ip_version();
+        socket_close_impl(socket->id);
+        create_socket_impl(socket);
+    }
+
     int sent_len = 0;
     int sent_len_before = 0;
     int sent_len_after = 0;