352 lines
8.3 KiB
C
352 lines
8.3 KiB
C
/** @file
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@brief TCP data handler
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This is not to be included by the application.
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*/
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/*
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* Copyright (c) 2016 Intel Corporation
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#ifndef __TCP_H
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#define __TCP_H
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#include <zephyr/types.h>
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#include <net/net_core.h>
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#include <net/net_ip.h>
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#include <net/net_pkt.h>
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#include <net/net_context.h>
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#include "connection.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/** Is this TCP context/socket used or not */
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#define NET_TCP_IN_USE BIT(0)
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/** Is the final segment sent */
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#define NET_TCP_FINAL_SENT BIT(1)
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/** Is the final segment received */
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#define NET_TCP_FINAL_RECV BIT(2)
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/** Is the socket shutdown for read/write */
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#define NET_TCP_IS_SHUTDOWN BIT(3)
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/** A retransmitted packet has been sent and not yet ack'd */
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#define NET_TCP_RETRYING BIT(4)
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/** MSS option has been set already */
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#define NET_TCP_RECV_MSS_SET BIT(5)
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/*
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* TCP connection states
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*/
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enum net_tcp_state {
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NET_TCP_CLOSED = 0,
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NET_TCP_LISTEN,
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NET_TCP_SYN_SENT,
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NET_TCP_SYN_RCVD,
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NET_TCP_ESTABLISHED,
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NET_TCP_CLOSE_WAIT,
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NET_TCP_LAST_ACK,
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NET_TCP_FIN_WAIT_1,
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NET_TCP_FIN_WAIT_2,
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NET_TCP_TIME_WAIT,
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NET_TCP_CLOSING,
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};
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/* TCP packet types */
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#define NET_TCP_FIN 0x01
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#define NET_TCP_SYN 0x02
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#define NET_TCP_RST 0x04
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#define NET_TCP_PSH 0x08
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#define NET_TCP_ACK 0x10
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#define NET_TCP_URG 0x20
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#define NET_TCP_CTL 0x3f
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#define NET_TCP_FLAGS(net_pkt) (NET_TCP_HDR(net_pkt)->flags & NET_TCP_CTL)
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/* TCP max window size */
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#define NET_TCP_MAX_WIN (4 * 1024)
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/* Maximal value of the sequence number */
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#define NET_TCP_MAX_SEQ 0xffffffff
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#define NET_TCP_MAX_OPT_SIZE 8
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#define NET_TCP_MSS_HEADER 0x02040000 /* MSS option */
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#define NET_TCP_WINDOW_HEADER 0x30300 /* Window scale option */
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#define NET_TCP_MSS_SIZE 4 /* MSS option size */
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#define NET_TCP_WINDOW_SIZE 3 /* Window scale option size */
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/* Max received bytes to buffer internally */
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#define NET_TCP_BUF_MAX_LEN 1280
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/* Max segment lifetime, in seconds */
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#define NET_TCP_MAX_SEG_LIFETIME 60
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struct net_context;
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struct net_tcp {
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/** Network context back pointer. */
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struct net_context *context;
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/** Cookie pointer passed to net_context_recv() */
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void *recv_user_data;
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/** ACK message timer */
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struct k_delayed_work ack_timer;
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/** Retransmit timer */
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struct k_timer retry_timer;
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/** List pointer used for TCP retransmit buffering */
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sys_slist_t sent_list;
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/** Max acknowledgment. */
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u32_t recv_max_ack;
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/** Current sequence number. */
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u32_t send_seq;
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/** Acknowledgment number to send in next packet. */
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u32_t send_ack;
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/** Last ACK value sent */
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u32_t sent_ack;
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/** Current retransmit period */
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u32_t retry_timeout_shift : 5;
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/** Flags for the TCP */
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u32_t flags : 8;
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/** Current TCP state */
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u32_t state : 4;
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/* A FIN packet has been queued for transmission */
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u32_t fin_queued : 1;
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/* An outbound FIN packet has been sent */
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u32_t fin_sent : 1;
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/* An inbound FIN packet has been received */
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u32_t fin_rcvd : 1;
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/* Tells if ack timer has been already cancelled. It might happen
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* that the timer is executed even if it is cancelled, this is because
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* of various timing issues when timer is scheduled to run.
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*/
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u32_t ack_timer_cancelled : 1;
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/** Remaining bits in this u32_t */
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u32_t _padding : 11;
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/** Accept callback to be called when the connection has been
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* established.
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*/
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net_tcp_accept_cb_t accept_cb;
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/**
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* Semaphore to signal TCP connection completion
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*/
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struct k_sem connect_wait;
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};
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static inline bool net_tcp_is_used(struct net_tcp *tcp)
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{
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NET_ASSERT(tcp);
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return tcp->flags & NET_TCP_IN_USE;
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}
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/**
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* @brief Register a callback to be called when TCP packet
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* is received corresponding to received packet.
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*
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* @param remote_addr Remote address of the connection end point.
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* @param local_addr Local address of the connection end point.
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* @param remote_port Remote port of the connection end point.
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* @param local_port Local port of the connection end point.
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* @param cb Callback to be called
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* @param user_data User data supplied by caller.
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* @param handle TCP handle that can be used when unregistering
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*
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* @return Return 0 if the registration succeed, <0 otherwise.
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*/
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static inline int net_tcp_register(const struct sockaddr *remote_addr,
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const struct sockaddr *local_addr,
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u16_t remote_port,
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u16_t local_port,
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net_conn_cb_t cb,
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void *user_data,
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struct net_conn_handle **handle)
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{
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return net_conn_register(IPPROTO_TCP, remote_addr, local_addr,
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remote_port, local_port, cb, user_data,
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handle);
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}
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/**
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* @brief Unregister TCP handler.
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*
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* @param handle Handle from registering.
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*
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* @return Return 0 if the unregistration succeed, <0 otherwise.
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*/
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static inline int net_tcp_unregister(struct net_conn_handle *handle)
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{
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return net_conn_unregister(handle);
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}
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const char * const net_tcp_state_str(enum net_tcp_state state);
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#if defined(CONFIG_NET_TCP)
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void net_tcp_change_state(struct net_tcp *tcp, enum net_tcp_state new_state);
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#else
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#define net_tcp_change_state(...)
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#endif
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/**
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* @brief Allocate TCP connection context.
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*
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* @param context Pointer to net_context that is tied to this TCP
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* context.
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*
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* @return Pointer TCP connection context. NULL if no available
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* context can be found.
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*/
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struct net_tcp *net_tcp_alloc(struct net_context *context);
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/**
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* @brief Release TCP connection context.
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*
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* @param tcp Pointer to net_tcp context.
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*
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* @return 0 if ok, < 0 if error
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*/
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int net_tcp_release(struct net_tcp *tcp);
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/**
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* @brief Send a TCP segment without any data. The returned buffer
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* is a ready made packet that can be sent via net_send_data()
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* function.
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*
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* @param tcp TCP context
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* @param flags TCP flags
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* @param options Pointer TCP options, NULL if no options.
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* @param optlen Length of the options.
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* @param local Source address, or NULL to use the local address of
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* the TCP context
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* @param remote Peer address
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* @param send_pkt Full IP + TCP header that is to be sent.
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*
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* @return 0 if ok, < 0 if error
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*/
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int net_tcp_prepare_segment(struct net_tcp *tcp, u8_t flags,
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void *options, size_t optlen,
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const struct sockaddr_ptr *local,
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const struct sockaddr *remote,
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struct net_pkt **send_pkt);
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/**
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* @brief Prepare a TCP ACK message that can be send to peer.
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*
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* @param tcp TCP context
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* @param remote Peer address
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* @param pkt Network buffer
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*
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* @return 0 if ok, < 0 if error
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*/
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int net_tcp_prepare_ack(struct net_tcp *tcp, const struct sockaddr *remote,
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struct net_pkt **pkt);
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/**
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* @brief Prepare a TCP RST message that can be send to peer.
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*
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* @param tcp TCP context
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* @param remote Peer address
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* @param pkt Network buffer
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*
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* @return 0 if ok, < 0 if error
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*/
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int net_tcp_prepare_reset(struct net_tcp *tcp, const struct sockaddr *remote,
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struct net_pkt **pkt);
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typedef void (*net_tcp_cb_t)(struct net_tcp *tcp, void *user_data);
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/**
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* @brief Go through all the TCP connections and call callback
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* for each of them.
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*
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* @param cb User supplied callback function to call.
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* @param user_data User specified data.
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*/
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void net_tcp_foreach(net_tcp_cb_t cb, void *user_data);
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/**
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* @brief Send available queued data over TCP connection
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*
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* @param context TCP context
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*
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* @return 0 if ok, < 0 if error
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*/
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int net_tcp_send_data(struct net_context *context);
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/**
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* @brief Enqueue a single packet for transmission
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*
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* @param context TCP context
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* @param pkt Packet
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*
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* @return 0 if ok, < 0 if error
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*/
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int net_tcp_queue_data(struct net_context *context, struct net_pkt *pkt);
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/**
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* @brief Sends one TCP packet initialized with the _prepare_*()
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* family of functions.
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*
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* @param pkt Packet
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*/
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int net_tcp_send_pkt(struct net_pkt *pkt);
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/**
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* @brief Handle a received TCP ACK
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*
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* @param cts Context
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* @param seq Received ACK sequence number
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*/
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void net_tcp_ack_received(struct net_context *ctx, u32_t ack);
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/**
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* @brief Calculates and returns the MSS for a given TCP context
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*
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* @param tcp TCP context
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*
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* @return Maximum Segment Size
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*/
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u16_t net_tcp_get_recv_mss(const struct net_tcp *tcp);
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/**
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* @brief Obtains the state for a TCP context
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*
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* @param tcp TCP context
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*/
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static inline enum net_tcp_state net_tcp_get_state(const struct net_tcp *tcp)
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{
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return (enum net_tcp_state)tcp->state;
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}
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#if defined(CONFIG_NET_TCP)
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void net_tcp_init(void);
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#else
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#define net_tcp_init(...)
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#endif
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#ifdef __cplusplus
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}
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#endif
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#endif /* __TCP_H */
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