diff options
Diffstat (limited to 'app/openvpn/doc/doxygen/doc_protocol_overview.h')
| -rw-r--r-- | app/openvpn/doc/doxygen/doc_protocol_overview.h | 69 |
1 files changed, 33 insertions, 36 deletions
diff --git a/app/openvpn/doc/doxygen/doc_protocol_overview.h b/app/openvpn/doc/doxygen/doc_protocol_overview.h index 26fed331..9edafcfb 100644 --- a/app/openvpn/doc/doxygen/doc_protocol_overview.h +++ b/app/openvpn/doc/doxygen/doc_protocol_overview.h @@ -5,7 +5,7 @@ * packet encryption, packet authentication, and * packet compression. * - * Copyright (C) 2010 Fox Crypto B.V. <openvpn@fox-it.com> + * Copyright (C) 2010-2014 Fox Crypto B.V. <openvpn@fox-it.com> * * * This program is free software; you can redistribute it and/or modify @@ -61,24 +61,26 @@ * following describes the various opcodes available. * * - Control channel messages: - * - \c P_CONTROL_HARD_RESET_CLIENT_V1 -- %Key method 1, initial %key + * - \ref P_CONTROL_HARD_RESET_CLIENT_V1 -- %Key method 1, initial %key * from client, forget previous state. - * - \c P_CONTROL_HARD_RESET_SERVER_V1 -- %Key method 1, initial %key + * - \ref P_CONTROL_HARD_RESET_SERVER_V1 -- %Key method 1, initial %key * from server, forget previous state. - * - \c P_CONTROL_HARD_RESET_CLIENT_V2 -- %Key method 2, initial %key + * - \ref P_CONTROL_HARD_RESET_CLIENT_V2 -- %Key method 2, initial %key * from client, forget previous state. - * - \c P_CONTROL_HARD_RESET_SERVER_V2 -- %Key method 2, initial %key + * - \ref P_CONTROL_HARD_RESET_SERVER_V2 -- %Key method 2, initial %key * from server, forget previous state. - * - \c P_CONTROL_SOFT_RESET_V1 -- New %key, with a graceful + * - \ref P_CONTROL_SOFT_RESET_V1 -- New %key, with a graceful * transition from old to new %key in the sense that a transition * window exists where both the old or new key_id can be used. - * - \c P_CONTROL_V1 -- Control channel packet (usually TLS + * - \ref P_CONTROL_V1 -- Control channel packet (usually TLS * ciphertext). - * - \c P_ACK_V1 -- Acknowledgement for control channel packets + * - \ref P_ACK_V1 -- Acknowledgement for control channel packets * received. * - Data channel messages: - * - \c P_DATA_V1 -- Data channel packet containing data channel + * - \ref P_DATA_V1 -- Data channel packet containing data channel * ciphertext. + * - \ref P_DATA_V2 -- Data channel packet containing peer-id and data + * channel ciphertext. * * @subsection network_protocol_external_key_id Session IDs and Key IDs * @@ -139,10 +141,10 @@ * channel is used to exchange random %key material for bidirectional * cipher and HMAC keys which will be used to secure data channel packets. * OpenVPN currently implements two %key methods. %Key method 1 directly - * derives keys using random bits obtained from the \c RAND_bytes() - * OpenSSL function. %Key method 2 mixes random %key material from both - * sides of the connection using the TLS PRF mixing function. %Key method - * 2 is the preferred method and is the default for OpenVPN 2.0. + * derives keys using random bits obtained from the \c rand_bytes() function. + * %Key method 2 mixes random %key material from both sides of the connection + * using the TLS PRF mixing function. %Key method 2 is the preferred method and + * is the default for OpenVPN 2.0+. * * The @ref key_generation "Data channel key generation" related page * describes the %key methods in more detail. @@ -173,27 +175,22 @@ * * @section network_protocol_data Structure of data channel messages * - * @subsection network_protocol_data_ciphertext Structure of ciphertext data channel messages - * - * The P_DATA_* payload represents encrypted, encapsulated tunnel packets - * which tend to be either IP packets or Ethernet frames. This is - * essentially the "payload" of the VPN. - * - * Data channel packets in ciphertext form consist of the following parts: - * - HMAC of ciphertext IV + ciphertext (if not disabled by \c --auth - * none). - * - Ciphertext IV (size is cipher-dependent, if not disabled by \c - * --no-iv). - * - Tunnel packet ciphertext. - * - * @subsection network_protocol_data_plaintext Structure of plaintext data channel messages - * - * Data channel packets in plaintext form consist of the following parts: - * - packet-id (4 or 8 bytes, if not disabled by --no-replay). - * - In TLS mode, 4 bytes are used because the implementation can - * force a TLS renegotation before \c 2^32 packets are sent. - * - In pre-shared %key mode, 8 bytes are used (sequence number and \c - * time_t value) to allow long-term %key usage without packet-id - * collisions. - * - User plaintext (n bytes). + * The P_DATA_* payload represents encapsulated tunnel packets which tend to be + * either IP packets or Ethernet frames. This is essentially the "payload" of + * the VPN. Data channel packets consist of a data channel header, and a + * payload. There are two possible formats: + * + * @par P_DATA_V1 + * P_DATA_V1 packets have a 1-byte header, carrying the \ref P_DATA_V1 \c opcode + * and \c key_id, followed by the payload:\n + * <tt> [ 5-bit opcode | 3-bit key_id ] [ payload ] </tt> + * + * @par P_DATA_V2 + * P_DATA_V2 packets have the same 1-byte opcode/key_id, but carrying the \ref + * P_DATA_V2 opcode, followed by a 3-byte peer-id, which uniquely identifies + * the peer:\n + * <tt> [ 5-bit opcode | 3-bit key_id ] [ 24-bit peer-id ] [ payload ] </tt> + * + * See @ref data_crypto for details on the data channel payload format. + * */ |