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/*
* Copyright (c) 2023-2024 Ian Marco Moffett and the Osmora Team.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of Hyra nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NSTP LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NSTP LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR STPHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef STP_SESSION_H_
#define STP_SESSION_H_
#include <ostp/crypto/aes.h>
#include <ostp/defs.h>
#include <stdint.h>
#define MAX_USERNAME_LEN 64
#define MAX_PASSWORD_LEN 256
/*
* 2^12 (4096) bytes is a common page size on
* modern systems, this could lead to potential
* optimizations.
*/
#define MESSAGE_SIZE (1 << 12)
/* Session Request option bits */
#define SESSION_REQ_USER BIT(0)
#define SESSION_REQ_P2P BIT(1)
/*
* For ACKing/TRUNCing packets e.g.,
* peer blocks
*/
#define ACK_WORD 0xAC7E
#define TRUNC_WORD 0x782C
#define PB_N_PEERS 16
#define PB_N_BLOCKS 16
/*
* The Session Request is sent from the client to the
* server and contains options, public key and some
* optional padding.
*
* @options: Flags/options
* @pubkey: Ephemeral public key.
* @pad: Random padding used to obsecure message length
* (can be 8 to 32 bytes, optional)
*
* -- Option/flag bits --
*
* Bit number
* /
* 0 1 2 3 4 5 6
* ~ ~ ~ ~ ~ ~ ~
* U P R R R R R
* \
* Purpose
*
* U: User auth.
* P: Peer-to-peer.
* R: Reserved, keep zero.
*/
struct session_request {
uint8_t options;
uint8_t pubkey[32];
uint8_t pad[8];
} PACKED;
/*
* The `peer' structure describes a peer on
* an OSTP server running in peer-to-peer mode.
*
* @pad: Must be all 1s, treat invalid otherwise
* @port: Port peer accepts connections on
* @host: Host peer is at
*/
struct peer {
uint8_t pad[1];
uint16_t port;
char host[IP_LEN_MAX];
};
/*
* If P2P is enabled and supported, the OCS
* sends one or more peer blocks in a consecutive
* manner. Each peer block can list up to 16 peers
* max. If the `seq' field is greater than zero and
* the list of peers within the current block is full,
* the client may either request the next peer block by
* sending an ACK packet or terminating the connection
* by sending a TRUNC packet.
*
* @peers: List of available peers within this block
* @seq: Descending one-based block sequence number (0=invalid)
*/
struct peer_block {
struct peer peers[PB_N_PEERS];
uint8_t seq;
} PACKED;
/* Peer/block counts must be powers of two */
CTASSERT((PB_N_PEERS & 1) == 0, "PB_N_PEERS not power-of-two!");
CTASSERT((PB_N_BLOCKS & 1) == 0, "PB_N_BLOCKS not power-of-two!");
/*
* Structure containing user information
* for password protected channels.
*/
struct session_auth {
char username[MAX_USERNAME_LEN];
char password[MAX_PASSWORD_LEN];
uint8_t code;
};
/*
* OSTP Message Frame containing an IV, AES
* GCM tag, payload length and payload
* with encrypted data.
*/
struct msg_frame {
uint8_t iv[AES_IV_SIZE];
uint8_t tag[AES_GCM_TAG_SIZE];
uint16_t len;
uint8_t payload[MESSAGE_SIZE];
};
int send_frame(int client_fd, void *data, size_t len,
const unsigned char *session_key);
int recv_frame(int client_fd, size_t len, const unsigned char *session_key,
void *res);
#endif /* STP_SESSION_H_ */
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