Some quick code to use UDP-only (no TCP) with mBed. Echos received packets and sends packets when a button is pressed
tcp_out.c File Reference
Transmission Control Protocol, outgoing traffic. More...
Go to the source code of this file.
Functions | |
static void | tcp_output_segment (struct tcp_seg *seg, struct tcp_pcb *pcb) |
Called by tcp_output() to actually send a TCP segment over IP. | |
err_t | tcp_send_ctrl (struct tcp_pcb *pcb, u8_t flags) |
Called by tcp_close() to send a segment including flags but not data. | |
err_t | tcp_write (struct tcp_pcb *pcb, const void *data, u16_t len, u8_t apiflags) |
Write data for sending (but does not send it immediately). | |
err_t | tcp_enqueue (struct tcp_pcb *pcb, void *arg, u16_t len, u8_t flags, u8_t apiflags, u8_t optflags) |
Enqueue data and/or TCP options for transmission. | |
err_t | tcp_output (struct tcp_pcb *pcb) |
Find out what we can send and send it. | |
void | tcp_rst (u32_t seqno, u32_t ackno, struct ip_addr *local_ip, struct ip_addr *remote_ip, u16_t local_port, u16_t remote_port) |
Send a TCP RESET packet (empty segment with RST flag set) either to abort a connection or to show that there is no matching local connection for a received segment. | |
void | tcp_rexmit_rto (struct tcp_pcb *pcb) |
Requeue all unacked segments for retransmission. | |
void | tcp_rexmit (struct tcp_pcb *pcb) |
Requeue the first unacked segment for retransmission. | |
void | tcp_rexmit_fast (struct tcp_pcb *pcb) |
Handle retransmission after three dupacks received. | |
void | tcp_keepalive (struct tcp_pcb *pcb) |
Send keepalive packets to keep a connection active although no data is sent over it. | |
void | tcp_zero_window_probe (struct tcp_pcb *pcb) |
Send persist timer zero-window probes to keep a connection active when a window update is lost. |
Detailed Description
Transmission Control Protocol, outgoing traffic.
The output functions of TCP.
Definition in file tcp_out.c.
Function Documentation
err_t tcp_enqueue | ( | struct tcp_pcb * | pcb, |
void * | arg, | ||
u16_t | len, | ||
u8_t | flags, | ||
u8_t | apiflags, | ||
u8_t | optflags | ||
) |
Enqueue data and/or TCP options for transmission.
Called by tcp_connect(), tcp_listen_input(), tcp_send_ctrl() and tcp_write().
- Parameters:
-
pcb Protocol control block for the TCP connection to enqueue data for. arg Pointer to the data to be enqueued for sending. len Data length in bytes flags tcp header flags to set in the outgoing segment apiflags combination of following flags : - TCP_WRITE_FLAG_COPY (0x01) data will be copied into memory belonging to the stack
- TCP_WRITE_FLAG_MORE (0x02) for TCP connection, PSH flag will be set on last segment sent,
optflags options to include in segment later on (see definition of struct tcp_seg)
void tcp_keepalive | ( | struct tcp_pcb * | pcb ) |
Send keepalive packets to keep a connection active although no data is sent over it.
Called by tcp_slowtmr()
- Parameters:
-
pcb the tcp_pcb for which to send a keepalive packet
err_t tcp_output | ( | struct tcp_pcb * | pcb ) |
static void tcp_output_segment | ( | struct tcp_seg * | seg, |
struct tcp_pcb * | pcb | ||
) | [static] |
Called by tcp_output() to actually send a TCP segment over IP.
- Parameters:
-
seg the tcp_seg to send pcb the tcp_pcb for the TCP connection used to send the segment
void tcp_rexmit | ( | struct tcp_pcb * | pcb ) |
Requeue the first unacked segment for retransmission.
Called by tcp_receive() for fast retramsmit.
- Parameters:
-
pcb the tcp_pcb for which to retransmit the first unacked segment
void tcp_rexmit_fast | ( | struct tcp_pcb * | pcb ) |
void tcp_rexmit_rto | ( | struct tcp_pcb * | pcb ) |
Requeue all unacked segments for retransmission.
Called by tcp_slowtmr() for slow retransmission.
- Parameters:
-
pcb the tcp_pcb for which to re-enqueue all unacked segments
void tcp_rst | ( | u32_t | seqno, |
u32_t | ackno, | ||
struct ip_addr * | local_ip, | ||
struct ip_addr * | remote_ip, | ||
u16_t | local_port, | ||
u16_t | remote_port | ||
) |
Send a TCP RESET packet (empty segment with RST flag set) either to abort a connection or to show that there is no matching local connection for a received segment.
Called by tcp_abort() (to abort a local connection), tcp_input() (if no matching local pcb was found), tcp_listen_input() (if incoming segment has ACK flag set) and tcp_process() (received segment in the wrong state)
Since a RST segment is in most cases not sent for an active connection, tcp_rst() has a number of arguments that are taken from a tcp_pcb for most other segment output functions.
- Parameters:
-
seqno the sequence number to use for the outgoing segment ackno the acknowledge number to use for the outgoing segment local_ip the local IP address to send the segment from remote_ip the remote IP address to send the segment to local_port the local TCP port to send the segment from remote_port the remote TCP port to send the segment to
err_t tcp_send_ctrl | ( | struct tcp_pcb * | pcb, |
u8_t | flags | ||
) |
Called by tcp_close() to send a segment including flags but not data.
- Parameters:
-
pcb the tcp_pcb over which to send a segment flags the flags to set in the segment header
- Returns:
- ERR_OK if sent, another err_t otherwise
err_t tcp_write | ( | struct tcp_pcb * | pcb, |
const void * | data, | ||
u16_t | len, | ||
u8_t | apiflags | ||
) |
Write data for sending (but does not send it immediately).
It waits in the expectation of more data being sent soon (as it can send them more efficiently by combining them together). To prompt the system to send data now, call tcp_output() after calling tcp_write().
- Parameters:
-
pcb Protocol control block of the TCP connection to enqueue data for. data pointer to the data to send len length (in bytes) of the data to send apiflags combination of following flags : - TCP_WRITE_FLAG_COPY (0x01) data will be copied into memory belonging to the stack
- TCP_WRITE_FLAG_MORE (0x02) for TCP connection, PSH flag will be set on last segment sent,
- Returns:
- ERR_OK if enqueued, another err_t on error
- See also:
- tcp_write()
void tcp_zero_window_probe | ( | struct tcp_pcb * | pcb ) |
Send persist timer zero-window probes to keep a connection active when a window update is lost.
Called by tcp_slowtmr()
- Parameters:
-
pcb the tcp_pcb for which to send a zero-window probe packet
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