lwIP 1.3.0: lwip/src/core/tcp.c File Reference

void tcp_abort ( struct tcp_pcb * pcb )

Aborts a connection by sending a RST to the remote host and 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

void tcp_accept	(	struct tcp_pcb *	pcb,
		err_t()(void arg, struct tcp_pcb *newpcb, err_t err)	accept
	)

Used for specifying the function that should be called when a LISTENing connection has been connected to another host.

Parameters:

	pcb	tcp_pcb to set the accept callback
	accept	callback function to call for this pcb when LISTENing connection has been connected to another host

struct tcp_pcb* tcp_alloc ( u8_t prio ) [read]

Allocate a new tcp_pcb structure.

Parameters:

prio

priority for the new pcb

Returns:: a new tcp_pcb that initially is in state CLOSED

void tcp_arg	(	struct tcp_pcb *	pcb,
		void *	arg
	)

Used to specify the argument that should be passed callback functions.

Parameters:

	pcb	tcp_pcb to set the callback argument
	arg	void pointer argument to pass to callback functions

err_t tcp_bind	(	struct tcp_pcb *	pcb,
		struct ip_addr *	ipaddr,
		u16_t	port
	)

Binds the connection to a local portnumber and IP address. If the IP address is not given (i.e., ipaddr == NULL), the IP address of the outgoing network interface is used instead.

Parameters:

	pcb	the tcp_pcb to bind (no check is done whether this pcb is already bound!)
	ipaddr	the local ip address to bind to (use IP_ADDR_ANY to bind to any local address
	port	the local port to bind to

Returns:: ERR_USE if the port is already in use ERR_OK if bound

err_t tcp_close ( struct tcp_pcb * pcb )

Closes the connection held by the PCB.

Listening pcbs are freed and may not be referenced any more. Connection pcbs are freed if not yet connected and may not be referenced any more. If a connection is established (at least SYN received or in a closing state), the connection is closed, and put in a closing state. The pcb is then automatically freed in tcp_slowtmr(). It is therefore unsafe to reference it.

Parameters:

pcb

the tcp_pcb to close

Returns:: ERR_OK if connection has been closed another err_t if closing failed and pcb is not freed

err_t tcp_connect	(	struct tcp_pcb *	pcb,
		struct ip_addr *	ipaddr,
		u16_t	port,
		err_t()(void arg, struct tcp_pcb *tpcb, err_t err)	connected
	)

Connects to another host. The function given as the "connected" argument will be called when the connection has been established.

Parameters:

	pcb	the tcp_pcb used to establish the connection
	ipaddr	the remote ip address to connect to
	port	the remote tcp port to connect to
	connected	callback function to call when connected (or on error)

Returns:: ERR_VAL if invalid arguments are given ERR_OK if connect request has been sent other err_t values if connect request couldn't be sent

void tcp_debug_print ( struct tcp_hdr * tcphdr )

Print a tcp header for debugging purposes.

Parameters:

tcphdr

pointer to a struct tcp_hdr

void tcp_debug_print_flags ( u8_t flags )

Print tcp flags for debugging purposes.

Parameters:

flags

tcp flags, all active flags are printed

void tcp_debug_print_pcbs ( void )

Print all tcp_pcbs in every list for debugging purposes.

void tcp_debug_print_state ( enum tcp_state s )

Print a tcp state for debugging purposes.

Parameters:

s

enum tcp_state to print

u16_t tcp_eff_send_mss	(	u16_t	sendmss,
		struct ip_addr *	addr
	)

Calcluates the effective send mss that can be used for a specific IP address by using ip_route to determin the netif used to send to the address and calculating the minimum of TCP_MSS and that netif's mtu (if set).

void tcp_err	(	struct tcp_pcb *	pcb,
		void()(void arg, err_t err)	errf
	)

Used to specify the function that should be called when a fatal error has occured on the connection.

Parameters:

	pcb	tcp_pcb to set the err callback
	errf	callback function to call for this pcb when a fatal error has occured on the connection

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.

Automatically called from tcp_tmr().

struct tcp_pcb* tcp_listen_with_backlog	(	struct tcp_pcb *	pcb,
		u8_t	backlog
	)			`[read]`

Set the state of the connection to be LISTEN, which means that it is able to accept incoming connections. The protocol control block is reallocated in order to consume less memory. Setting the connection to LISTEN is an irreversible process.

Parameters:

	pcb	the original tcp_pcb
	backlog	the incoming connections queue limit

Returns:: tcp_pcb used for listening, consumes less memory.

Note:: The original tcp_pcb is freed. This function therefore has to be called like this: tpcb = tcp_listen(tpcb);

struct tcp_pcb* tcp_new ( void ) [read]

Creates a new TCP protocol control block but doesn't place it on any of the TCP PCB lists. The pcb is not put on any list until binding using tcp_bind().

u32_t tcp_next_iss ( void )

Calculates a new initial sequence number for new connections.

Returns:: u32_t pseudo random sequence number

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!

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 also deallocated!

s16_t tcp_pcbs_sane ( void )

Check state consistency of the tcp_pcb lists.

void tcp_poll	(	struct tcp_pcb *	pcb,
		err_t()(void arg, struct tcp_pcb *tpcb)	poll,
		u8_t	interval
	)

Used to specify the function that should be called periodically from TCP. The interval is specified in terms of the TCP coarse timer interval, which is called twice a second.

void tcp_recv	(	struct tcp_pcb *	pcb,
		err_t()(void arg, struct tcp_pcb tpcb, struct pbuf p, err_t err)	recv
	)

Used to specify the function that should be called when a TCP connection receives data.

Parameters:

	pcb	tcp_pcb to set the recv callback
	recv	callback function to call for this pcb when data is received

void tcp_recved	(	struct tcp_pcb *	pcb,
		u16_t	len
	)

This function should be called by the application when it has processed the data. The purpose is to advertise a larger window when the data has been processed.

Parameters:

	pcb	the tcp_pcb for which data is read
	len	the amount of bytes that have been read by the application

struct tcp_seg* tcp_seg_copy ( struct tcp_seg * seg ) [read]

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

u8_t tcp_seg_free ( struct tcp_seg * seg )

Frees a TCP segment (tcp_seg structure).

Parameters:

seg

single tcp_seg to free

Returns:: the number of pbufs that were deallocated

u8_t 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

Returns:: the number of pbufs that were deallocated

void tcp_sent	(	struct tcp_pcb *	pcb,
		err_t()(void arg, struct tcp_pcb *tpcb, u16_t len)	sent
	)

Used to specify the function that should be called when TCP data has been successfully delivered to the remote host.

Parameters:

	pcb	tcp_pcb to set the sent callback
	sent	callback function to call for this pcb when data is successfully sent

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

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().

void tcp_tmr ( void )

Called periodically to dispatch TCP timers.

struct tcp_pcb* tcp_active_pcbs

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

struct tcp_pcb* tcp_bound_pcbs

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

union tcp_listen_pcbs_t tcp_listen_pcbs

List of all TCP PCBs in LISTEN state

struct tcp_pcb* tcp_tw_pcbs

List of all TCP PCBs in TIME-WAIT state

tcp.c File Reference

Functions

Variables

Detailed Description

Function Documentation

Variable Documentation


Functions
void	tcp_tmr (void)
err_t	tcp_close (struct tcp_pcb *pcb)
void	tcp_abort (struct tcp_pcb *pcb)
err_t	tcp_bind (struct tcp_pcb pcb, struct ip_addr ipaddr, u16_t port)
struct tcp_pcb *	tcp_listen_with_backlog (struct tcp_pcb *pcb, u8_t backlog)
void	tcp_recved (struct tcp_pcb *pcb, u16_t len)
err_t	tcp_connect (struct tcp_pcb pcb, struct ip_addr ipaddr, u16_t port, err_t(connected)(void arg, struct tcp_pcb *tpcb, err_t err))
void	tcp_slowtmr (void)
void	tcp_fasttmr (void)
u8_t	tcp_segs_free (struct tcp_seg *seg)
u8_t	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)
struct tcp_pcb *	tcp_alloc (u8_t prio)
struct tcp_pcb *	tcp_new (void)
void	tcp_arg (struct tcp_pcb pcb, void arg)
void	tcp_recv (struct tcp_pcb pcb, err_t(recv)(void arg, struct tcp_pcb tpcb, struct pbuf *p, err_t err))
void	tcp_sent (struct tcp_pcb pcb, err_t(sent)(void arg, struct tcp_pcb tpcb, u16_t len))
void	tcp_err (struct tcp_pcb pcb, void(errf)(void *arg, err_t err))
void	tcp_accept (struct tcp_pcb pcb, err_t(accept)(void arg, struct tcp_pcb newpcb, err_t err))
void	tcp_poll (struct tcp_pcb pcb, err_t(poll)(void arg, struct tcp_pcb tpcb), 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 (void)
u16_t	tcp_eff_send_mss (u16_t sendmss, struct ip_addr *addr)
void	tcp_debug_print (struct tcp_hdr *tcphdr)
void	tcp_debug_print_state (enum tcp_state s)
void	tcp_debug_print_flags (u8_t flags)
void	tcp_debug_print_pcbs (void)
s16_t	tcp_pcbs_sane (void)
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