9976ebb24b
Rework how data is queued for the TCP connections:
* net_context no longer allocates net_pkt for TCP connections. This
was not only inefficient (net_context has no knowledge of the TX
window size), but also error-prone in certain configuration (for
example when IP fragmentation was enabled, net_context may attempt
to allocate enormous packet, instead of let the data be fragmented
for the TCP stream.
* Instead, implement already defined `net_tcp_queue()` API, which
takes raw buffer and length. This allows to take TX window into
account and also better manage the allocated net_buf's (like for
example avoid allocation if there's still room in the buffer). In
result, the TCP stack will not only no longer exceed the TX window,
but also prevent empty gaps in allocated net_buf's, which should
lead to less out-of-mem issues with the stack.
* As net_pkt-based `net_tcp_queue_data()` is no longer in use, it was
removed.
Signed-off-by: Robert Lubos <robert.lubos@nordicsemi.no>
124 lines
3.1 KiB
C
124 lines
3.1 KiB
C
/*
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* Copyright (c) 2018-2019 Intel Corporation
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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/**
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* @brief Transmission Control Protocol (TCP)
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*
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* - net_tcp_get() is called by net_context_get(AF_INET, SOCK_STREAM,
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IPPROTO_TCP, ...) and creates struct tcp for the net_context
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* - net_tcp_listen()/net_tcp_accept() listen/accept
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* - At the reception of SYN on the listening net_context, a new pair
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* of net_context/struct tcp registers a new net_conn handle
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* with the tcp_recv() as a callback
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* - net_tcp_queue() queues the data for the transmission
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* - The incoming data is delivered up through the context->recv_cb
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* - net_tcp_put() closes the connection
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*
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* NOTE: The present API is provided in order to make the integration
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* into the ip stack and the socket layer less intrusive.
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*
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* Semantically cleaner use is possible (and might be exposed),
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* look into the unit test tests/net/tcp for insights.
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*/
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#ifndef TCP_H
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#define TCP_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <errno.h>
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#include <sys/types.h>
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/**
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* @brief Allocate a TCP connection for the net_context
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* and mutually link the net_context and TCP connection.
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*
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* @param context Network context
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*
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* @return 0 on success, < 0 on error
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*/
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int net_tcp_get(struct net_context *context);
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/**
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* @brief Close and delete the TCP connection for the net_context
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*
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* @param context Network context
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*
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* @return 0 on success, < 0 on error
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*/
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int net_tcp_put(struct net_context *context);
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/**
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* @brief Listen for an incoming TCP connection
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*
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* @param context Network context
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*
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* @return 0 if successful, < 0 on error
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*/
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int net_tcp_listen(struct net_context *context);
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/**
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* @brief Register an accept callback
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*
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* @param context Network context
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* @param cb net_tcp_accept_cb_t callback
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* @param user_data User data passed as an argument in the callback
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*
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* @return 0 if successful, < 0 on error
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*/
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int net_tcp_accept(struct net_context *context, net_tcp_accept_cb_t cb,
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void *user_data);
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/* TODO: split into 2 functions, conn -> context, queue -> send? */
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/* The following functions are provided solely for the compatibility
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* with the old TCP
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*/
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/**
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* @brief Return struct net_tcp_hdr pointer
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*
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* @param pkt Network packet
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* @param tcp_access Helper variable for accessing TCP header
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*
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* @return Pointer to the TCP header on success, NULL on error
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*/
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struct net_tcp_hdr *net_tcp_input(struct net_pkt *pkt,
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struct net_pkt_data_access *tcp_access);
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/* TODO: net_tcp_input() isn't used by TCP and might be dropped with little
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* re-factoring
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*/
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/* No ops, provided for compatibility with the old TCP */
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#if defined(CONFIG_NET_NATIVE_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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int net_tcp_update_recv_wnd(struct net_context *context, int32_t delta);
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int net_tcp_finalize(struct net_pkt *pkt, bool force_chksum);
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#if defined(CONFIG_NET_TEST_PROTOCOL)
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/**
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* @brief Handle an incoming TCP packet
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*
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* This function is provided for the TCP sanity check and will be eventually
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* dropped.
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*
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* @param pkt Network packet
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*/
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void tcp_input(struct net_pkt *pkt);
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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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