extmod/{modlwip,modsocket}: Add support for SO_BROADCAST socket option.

Signed-off-by: Wang Xuancong <xuancong84@gmail.com>

extmod/modlwip.c

@@ -1377,7 +1377,8 @@ STATIC mp_obj_t lwip_socket_setsockopt(size_t n_args, const mp_obj_t *args) {
 
     switch (opt) {
         // level: SOL_SOCKET
-        case SOF_REUSEADDR: {
+        case SOF_REUSEADDR:
+        case SOF_BROADCAST: {
             mp_int_t val = mp_obj_get_int(args[3]);
             // Options are common for UDP and TCP pcb's.
             if (val) {
@@ -1786,6 +1787,7 @@ STATIC const mp_rom_map_elem_t mp_module_lwip_globals_table[] = {
 
     { MP_ROM_QSTR(MP_QSTR_SOL_SOCKET), MP_ROM_INT(1) },
     { MP_ROM_QSTR(MP_QSTR_SO_REUSEADDR), MP_ROM_INT(SOF_REUSEADDR) },
+    { MP_ROM_QSTR(MP_QSTR_SO_BROADCAST), MP_ROM_INT(SOF_BROADCAST) },
 
     { MP_ROM_QSTR(MP_QSTR_IPPROTO_IP), MP_ROM_INT(0) },
     { MP_ROM_QSTR(MP_QSTR_IP_ADD_MEMBERSHIP), MP_ROM_INT(IP_ADD_MEMBERSHIP) },

extmod/modnetwork.h

@@ -43,6 +43,7 @@
 
 // Common option flags per-socket.
 #define MOD_NETWORK_SO_REUSEADDR    (0x0004)
+#define MOD_NETWORK_SO_BROADCAST    (0x0020)
 #define MOD_NETWORK_SO_KEEPALIVE    (0x0008)
 #define MOD_NETWORK_SO_SNDTIMEO     (0x1005)
 #define MOD_NETWORK_SO_RCVTIMEO     (0x1006)

extmod/modsocket.c

@@ -631,6 +631,7 @@ STATIC const mp_rom_map_elem_t mp_module_socket_globals_table[] = {
 
     { MP_ROM_QSTR(MP_QSTR_SOL_SOCKET), MP_ROM_INT(MOD_NETWORK_SOL_SOCKET) },
     { MP_ROM_QSTR(MP_QSTR_SO_REUSEADDR), MP_ROM_INT(MOD_NETWORK_SO_REUSEADDR) },
+    { MP_ROM_QSTR(MP_QSTR_SO_BROADCAST), MP_ROM_INT(MOD_NETWORK_SO_BROADCAST) },
     { MP_ROM_QSTR(MP_QSTR_SO_KEEPALIVE), MP_ROM_INT(MOD_NETWORK_SO_KEEPALIVE) },
     { MP_ROM_QSTR(MP_QSTR_SO_SNDTIMEO), MP_ROM_INT(MOD_NETWORK_SO_SNDTIMEO) },
     { MP_ROM_QSTR(MP_QSTR_SO_RCVTIMEO), MP_ROM_INT(MOD_NETWORK_SO_RCVTIMEO) },