LWIP之初使用--->UDP主动向某个IP发数据

void send_data(void)
{
   struct pbuf *q = NULL;
   const char* reply = "I'm here ! Are you There ? \n";
   struct udp_pcb *upcb;
   struct ip_addr addr;
   IP4_ADDR(&addr, 192,168,0,125);

   upcb = udp_new();
   udp_bind(upcb, IP_ADDR_ANY, UDP_ECHO_PORT);

   q = pbuf_alloc(PBUF_TRANSPORT, strlen(reply)+1, PBUF_RAM);
   if(!q)
   {
   	 printf("out of PBUF_RAM\n");
	 return;
   }
   memset(q->payload, 0 , q->len);
   memcpy(q->payload, reply, strlen(reply));
   udp_sendto(upcb, q, &addr, 8080);
   pbuf_free(q);
}

在需要的地方调用该函数就可以向IP为192.168.0.125的8080端口发数据 I'm here ! Are you There ?  可以根据自己的需要进行修改。