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The prototypes for the following functions lie in ‘gnutls/dtls.h’.
key: is a random key to be used at cookie generation
client_data: contains data identifying the client (i.e. address)
client_data_size: The size of client’s data
prestate: The previous cookie returned by gnutls_dtls_cookie_verify()
ptr: A transport pointer to be used by push_func
push_func: A function that will be used to reply
This function can be used to prevent denial of service
attacks to a DTLS server by requiring the client to
reply using a cookie sent by this function. That way
it can be ensured that a client we allocated resources
for (i.e. gnutls_session_t ) is the one that the
original incoming packet was originated from.
Returns: the number of bytes sent, or a negative error code.
Since: 3.0
key: is a random key to be used at cookie generation
client_data: contains data identifying the client (i.e. address)
client_data_size: The size of client’s data
_msg: An incoming message that initiates a connection.
msg_size: The size of the message.
prestate: The cookie of this client.
This function will verify an incoming message for
a valid cookie. If a valid cookie is returned then
it should be associated with the session using
gnutls_dtls_prestate_set() ;
Returns: GNUTLS_E_SUCCESS (0) on success, or a negative error code.
Since: 3.0
session: is a gnutls_session_t structure.
This function will return the actual maximum transfer unit for application data. I.e. DTLS headers are subtracted from the actual MTU.
Returns: the maximum allowed transfer unit.
Since: 3.0
session: is a gnutls_session_t structure.
This function will return the MTU size as set with
gnutls_dtls_set_mtu() . This is not the actual MTU
of data you can transmit. Use gnutls_dtls_get_data_mtu()
for that reason.
Returns: the set maximum transfer unit.
Since: 3.0
session: is a gnutls_session_t structure.
This function will return the milliseconds remaining
for a retransmission of the previously sent handshake
message. This function is useful when DTLS is used in
non-blocking mode, to estimate when to call gnutls_handshake()
if no packets have been received.
Returns: the remaining time in milliseconds.
Since: 3.0
session: a new session
prestate: contains the client’s prestate
This function will associate the prestate acquired by the cookie authentication with the client, with the newly established session.
Since: 3.0
session: is a gnutls_session_t structure.
mtu: The maximum transfer unit of the interface
This function will set the maximum transfer unit of the interface that DTLS packets are expected to leave from.
Since: 3.0
session: is a gnutls_session_t structure.
retrans_timeout: The time at which a retransmission will occur in milliseconds
total_timeout: The time at which the connection will be aborted, in milliseconds.
This function will set the timeouts required for the DTLS handshake
protocol. The retransmission timeout is the time after which a
message from the peer is not received, the previous messages will
be retransmitted. The total timeout is the time after which the
handshake will be aborted with GNUTLS_E_TIMEDOUT .
The DTLS protocol recommends the values of 1 sec and 60 seconds respectively.
If the retransmission timeout is zero then the handshake will operate
in a non-blocking way, i.e., return GNUTLS_E_AGAIN .
Since: 3.0
session: is a gnutls_session_t structure.
Returns the number of discarded packets in a DTLS connection.
Returns: The number of discarded packets.
Since: 3.0
Next: X509 certificate API, Previous: Core TLS API, Up: API reference [Contents][Index]