text: #ifndef __TCP_HELPER_H__
  #define __TCP_HELPER_H__
  
  #include "../lwip_check.h"
  #include "lwip/arch.h"
  #include "lwip/tcp.h"
  
  /* counters used for test_tcp_counters_* callback functions */
  struct test_tcp_counters {
    u32_t recv_calls;
    u32_t recved_bytes;
    u32_t recv_calls_after_close;
    u32_t recved_bytes_after_close;
    u32_t close_calls;
    u32_t err_calls;
    err_t last_err;
    char* expected_data;
    u32_t expected_data_len;
  };
  
  /* Helper functions */
  void tcp_remove_all(void);
  
  struct pbuf* tcp_create_segment(struct ip_addr* src_ip, struct ip_addr* dst_ip,
                     u16_t src_port, u16_t dst_port, void* data, size_t data_len,
                     u32_t seqno, u32_t ackno, u8_t headerflags);
  struct pbuf* tcp_create_rx_segment(struct tcp_pcb* pcb, void* data, size_t data_len,
                     u32_t seqno_offset, u32_t ackno_offset, u8_t headerflags);
  void tcp_set_state(struct tcp_pcb* pcb, enum tcp_state state, struct ip_addr* local_ip,
                     struct ip_addr* remote_ip, u16_t local_port, u16_t remote_port);
  void test_tcp_counters_err(void* arg, err_t err);
  err_t test_tcp_counters_recv(void* arg, struct tcp_pcb* pcb, struct pbuf* p, err_t err);
  
  struct tcp_pcb* test_tcp_new_counters_pcb(struct test_tcp_counters* counters);
  
  #endif
  