tcp.c File Reference

#include "lwip/opt.h"
#include "lwip/def.h"
#include "lwip/mem.h"
#include "lwip/memp.h"
#include "lwip/tcp.h"
#include "lwip/priv/tcp_priv.h"
#include "lwip/debug.h"
#include "lwip/stats.h"
#include "lwip/ip6.h"
#include "lwip/ip6_addr.h"
#include "lwip/nd6.h"
#include <string.h>
#include "path/to/my/lwip_hooks.h"

Functions
void	tcp_init (void)
void	tcp_free (struct tcp_pcb *pcb)
void	tcp_tmr (void)
void	tcp_backlog_delayed (struct tcp_pcb *pcb)
void	tcp_backlog_accepted (struct tcp_pcb *pcb)
err_t	tcp_close (struct tcp_pcb *pcb)
err_t	tcp_shutdown (struct tcp_pcb *pcb, int shut_rx, int shut_tx)
void	tcp_abandon (struct tcp_pcb *pcb, int reset)
void	tcp_abort (struct tcp_pcb *pcb)
err_t	tcp_bind (struct tcp_pcb *pcb, const ip_addr_t *ipaddr, u16_t port)
void	tcp_bind_netif (struct tcp_pcb *pcb, const struct netif *netif)
struct tcp_pcb *	tcp_listen_with_backlog (struct tcp_pcb *pcb, u8_t backlog)
struct tcp_pcb *	tcp_listen_with_backlog_and_err (struct tcp_pcb *pcb, u8_t backlog, err_t *err)
u32_t	tcp_update_rcv_ann_wnd (struct tcp_pcb *pcb)
void	tcp_recved (struct tcp_pcb *pcb, u16_t len)
err_t	tcp_connect (struct tcp_pcb *pcb, const ip_addr_t *ipaddr, u16_t port, tcp_connected_fn connected)
void	tcp_slowtmr (void)
void	tcp_fasttmr (void)
void	tcp_txnow (void)
err_t	tcp_process_refused_data (struct tcp_pcb *pcb)
void	tcp_segs_free (struct tcp_seg *seg)
void	tcp_seg_free (struct tcp_seg *seg)
void	tcp_setprio (struct tcp_pcb *pcb, u8_t prio)
struct tcp_seg *	tcp_seg_copy (struct tcp_seg *seg)
err_t	tcp_recv_null (void *arg, struct tcp_pcb *pcb, struct pbuf *p, err_t err)
struct tcp_pcb *	tcp_alloc (u8_t prio)
struct tcp_pcb *	tcp_new (void)
struct tcp_pcb *	tcp_new_ip_type (u8_t type)
void	tcp_arg (struct tcp_pcb *pcb, void *arg)
void	tcp_recv (struct tcp_pcb *pcb, tcp_recv_fn recv)
void	tcp_sent (struct tcp_pcb *pcb, tcp_sent_fn sent)
void	tcp_err (struct tcp_pcb *pcb, tcp_err_fn err)
void	tcp_accept (struct tcp_pcb *pcb, tcp_accept_fn accept)
void	tcp_poll (struct tcp_pcb *pcb, tcp_poll_fn poll, u8_t interval)
void	tcp_pcb_purge (struct tcp_pcb *pcb)
void	tcp_pcb_remove (struct tcp_pcb **pcblist, struct tcp_pcb *pcb)
u32_t	tcp_next_iss (struct tcp_pcb *pcb)
u16_t	tcp_eff_send_mss_netif (u16_t sendmss, struct netif *outif, const ip_addr_t *dest)
void	tcp_netif_ip_addr_changed (const ip_addr_t *old_addr, const ip_addr_t *new_addr)
u8_t	tcp_ext_arg_alloc_id (void)
void	tcp_ext_arg_set_callbacks (struct tcp_pcb *pcb, uint8_t id, const struct tcp_ext_arg_callbacks *const callbacks)
void	tcp_ext_arg_set (struct tcp_pcb *pcb, uint8_t id, void *arg)
void *	tcp_ext_arg_get (const struct tcp_pcb *pcb, uint8_t id)
err_t	tcp_ext_arg_invoke_callbacks_passive_open (struct tcp_pcb_listen *lpcb, struct tcp_pcb *cpcb)

Variables
struct tcp_pcb *	tcp_bound_pcbs
union tcp_listen_pcbs_t	tcp_listen_pcbs
struct tcp_pcb *	tcp_active_pcbs
struct tcp_pcb *	tcp_tw_pcbs
struct tcp_pcb **const	tcp_pcb_lists []

Detailed Description

Transmission Control Protocol for IP See also TCP

Function Documentation

tcp_abandon()

void tcp_abandon	(	struct tcp_pcb *	pcb,
		int	reset
	)

Abandons a connection and optionally sends a RST to the remote host. Deletes the local protocol control block. This is done when a connection is killed because of shortage of memory.

Parameters

pcb	the tcp_pcb to abort
reset	boolean to indicate whether a reset should be sent

tcp_alloc()

struct tcp_pcb* tcp_alloc

(

u8_t

prio

)

Allocate a new tcp_pcb structure.

Parameters

prio	priority for the new pcb

Returns

a new tcp_pcb that initially is in state CLOSED

tcp_eff_send_mss_netif()

u16_t tcp_eff_send_mss_netif	(	u16_t	sendmss,
		struct netif *	outif,
		const ip_addr_t *	dest
	)

Calculates the effective send mss that can be used for a specific IP address by calculating the minimum of TCP_MSS and the mtu (if set) of the target netif (if not NULL).

tcp_ext_arg_invoke_callbacks_passive_open()

err_t tcp_ext_arg_invoke_callbacks_passive_open	(	struct tcp_pcb_listen *	lpcb,
		struct tcp_pcb *	cpcb
	)

This function calls the "passive_open" callback for all ext_args if a connection is in the process of being accepted. This is called just after the SYN is received and before a SYN/ACK is sent, to allow to modify the very first segment sent even on passive open. Naturally, the "accepted" callback of the pcb has not been called yet!

tcp_fasttmr()

void tcp_fasttmr

(

void

)

Is called every TCP_FAST_INTERVAL (250 ms) and process data previously "refused" by upper layer (application) and sends delayed ACKs or pending FINs.

Automatically called from tcp_tmr().

tcp_free()

void tcp_free

(

struct tcp_pcb *

pcb

)

Free a tcp pcb

tcp_init()

void tcp_init

(

void

)

Initialize this module.

tcp_netif_ip_addr_changed()

void tcp_netif_ip_addr_changed	(	const ip_addr_t *	old_addr,
		const ip_addr_t *	new_addr
	)

This function is called from netif.c when address is changed or netif is removed

Parameters

old_addr	IP address of the netif before change
new_addr	IP address of the netif after change or NULL if netif has been removed

tcp_next_iss()

u32_t tcp_next_iss

(

struct tcp_pcb *

pcb

)

Calculates a new initial sequence number for new connections.

Returns

u32_t pseudo random sequence number

tcp_pcb_purge()

void tcp_pcb_purge

(

struct tcp_pcb *

pcb

)

Purges a TCP PCB. Removes any buffered data and frees the buffer memory (pcb->ooseq, pcb->unsent and pcb->unacked are freed).

Parameters

pcb	tcp_pcb to purge. The pcb itself is not deallocated!

tcp_pcb_remove()

void tcp_pcb_remove	(	struct tcp_pcb **	pcblist,
		struct tcp_pcb *	pcb
	)

Purges the PCB and removes it from a PCB list. Any delayed ACKs are sent first.

Parameters

pcblist	PCB list to purge.
pcb	tcp_pcb to purge. The pcb itself is NOT deallocated!

tcp_process_refused_data()

err_t tcp_process_refused_data

(

struct tcp_pcb *

pcb

)

Pass pcb->refused_data to the recv callback

tcp_recv_null()

err_t tcp_recv_null	(	void *	arg,
		struct tcp_pcb *	pcb,
		struct pbuf *	p,
		err_t	err
	)

Default receive callback that is called if the user didn't register a recv callback for the pcb.

tcp_seg_copy()

struct tcp_seg* tcp_seg_copy

(

struct tcp_seg *

seg

)

Returns a copy of the given TCP segment. The pbuf and data are not copied, only the pointers

Parameters

seg	the old tcp_seg

Returns

a copy of seg

tcp_seg_free()

void tcp_seg_free

(

struct tcp_seg *

seg

)

Frees a TCP segment (tcp_seg structure).

Parameters

seg	single tcp_seg to free

tcp_segs_free()

void tcp_segs_free

(

struct tcp_seg *

seg

)

Deallocates a list of TCP segments (tcp_seg structures).

Parameters

seg	tcp_seg list of TCP segments to free

tcp_setprio()

void tcp_setprio	(	struct tcp_pcb *	pcb,
		u8_t	prio
	)

Sets the priority of a connection.

Parameters

pcb	the tcp_pcb to manipulate
prio	new priority

tcp_slowtmr()

void tcp_slowtmr

(

void

)

Called every 500 ms and implements the retransmission timer and the timer that removes PCBs that have been in TIME-WAIT for enough time. It also increments various timers such as the inactivity timer in each PCB.

Automatically called from tcp_tmr().

tcp_tmr()

void tcp_tmr

(

void

)

Called periodically to dispatch TCP timers.

tcp_txnow()

void tcp_txnow

(

void

)

Call tcp_output for all active pcbs that have TF_NAGLEMEMERR set

tcp_update_rcv_ann_wnd()

u32_t tcp_update_rcv_ann_wnd

(

struct tcp_pcb *

pcb

)

Update the state that tracks the available window space to advertise.

Returns how much extra window would be advertised if we sent an update now.

Variable Documentation

tcp_active_pcbs

struct tcp_pcb* tcp_active_pcbs

List of all TCP PCBs that are in a state in which they accept or send data.

tcp_bound_pcbs

struct tcp_pcb* tcp_bound_pcbs

List of all TCP PCBs bound but not yet (connected || listening)

tcp_listen_pcbs

union tcp_listen_pcbs_t tcp_listen_pcbs

List of all TCP PCBs in LISTEN state

tcp_pcb_lists

struct tcp_pcb** const tcp_pcb_lists[]

Initial value:

= {&tcp_listen_pcbs.pcbs, &tcp_bound_pcbs,
         &tcp_active_pcbs, &tcp_tw_pcbs
}

An array with all (non-temporary) PCB lists, mainly used for smaller code size

tcp_tw_pcbs

struct tcp_pcb* tcp_tw_pcbs

List of all TCP PCBs in TIME-WAIT state