ngtcp2_conn_write_connection_close

Synopsis

#include <ngtcp2/ngtcp2.h>

ngtcp2_ssize ngtcp2_conn_write_connection_close(ngtcp2_conn *conn, ngtcp2_path *path, ngtcp2_pkt_info *pi, uint8_t *dest, size_t destlen, const ngtcp2_ccerr *ccerr, ngtcp2_tstamp ts)

ngtcp2_conn_write_connection_close() writes a packet which contains CONNECTION_CLOSE frame(s) (type 0x1c or 0x1d) in the buffer pointed by dest whose capacity is destlen.

For client, destlen should be at least NGTCP2_MAX_UDP_PAYLOAD_SIZE.

If path is not NULL, this function stores the network path with which the packet should be sent. Each addr field must point to the buffer which should be at least sizeof(ngtcp2_sockaddr_union) bytes long. The assignment might not be done if nothing is written to dest.

If pi is not NULL, this function stores packet metadata in it if it succeeds. The metadata includes ECN markings.

If ccerr->type == ngtcp2_ccerr_type.NGTCP2_CCERR_TYPE_TRANSPORT, this function sends CONNECTION_CLOSE (type 0x1c) frame. If ccerr->type == ngtcp2_ccerr_type.NGTCP2_CCERR_TYPE_APPLICATION, it sends CONNECTION_CLOSE (type 0x1d) frame. Otherwise, it does not produce any data, and returns 0.

destlen could be shorten by some factors (e.g., server side amplification limit). This function returns NGTCP2_ERR_NOBUF if the resulting buffer is too small even if the given buffer has enough space.

This function must not be called from inside the callback functions.

At the moment, successful call to this function makes connection close. We may change this behaviour in the future to allow graceful shutdown.

This function returns the number of bytes written in dest if it succeeds, or one of the following negative error codes:

NGTCP2_ERR_NOMEM: Out of memory
NGTCP2_ERR_NOBUF: Buffer is too small
NGTCP2_ERR_INVALID_STATE: The current state does not allow sending CONNECTION_CLOSE frame.
NGTCP2_ERR_PKT_NUM_EXHAUSTED: Packet number is exhausted, and cannot send any more packet.
NGTCP2_ERR_CALLBACK_FAILURE: User callback failed