DTLS 1.2

DTLS 1.2 uses the TLS 1.2 handshake and cipher suite implementation over the DTLS datagram record layer. Header: noxtls_tls12.h with shared DTLS declarations in noxtls_dtls_common.h.

Use noxtls_dtls12_context_init to initialize a tls12_context_t for datagram transport. Configure MTU, retransmission, cookies, replay handling, and anti-amplification settings with the shared DTLS API.

Features

Area	Support
Record layer	DTLS 1.2 13-byte record header with epoch and 48-bit sequence number
Handshake	TLS 1.2 handshake over datagrams
Fragmentation	Handshake fragmentation and reassembly
Loss recovery	Flight buffering and retransmission timer configuration
Replay protection	Sliding replay window
DoS mitigation	HelloVerifyRequest cookie generation and verification
Transport	Callback-based datagram I/O using the TLS common callback API

API

noxtls_dtls12_context_init

noxtls_return_t noxtls_dtls12_context_init(tls12_context_t *ctx, tls_role_t role);

Initialize a TLS 1.2 context for DTLS 1.2 operation.

Returns: noxtls_return_t.

Handshake and Data

After initialization, use the TLS 1.2 handshake and data functions on the same context:

• noxtls_tls12_connect
• noxtls_tls12_accept
• noxtls_tls12_send
• noxtls_tls12_recv
• noxtls_tls12_close

Typical Setup

tls12_context_t ctx;

noxtls_dtls12_context_init(&ctx, TLS_ROLE_CLIENT);
noxtls_tls_set_io_callbacks(&ctx.base.base, send_cb, recv_cb, user_data);
noxtls_dtls_set_mtu(&ctx.base, 1200);
dtls_set_retransmit(&ctx.base, 1000, 2000, 5);

noxtls_tls12_connect(&ctx);

See DTLS common API for record, fragmentation, cookie, and replay helper functions.