437 lines
12 KiB
C
437 lines
12 KiB
C
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/**
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* @file SPProtoEncoder.c
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* @author Ambroz Bizjak <ambrop7@gmail.com>
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*
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* @section LICENSE
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the author nor the
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* names of its contributors may be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <string.h>
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#include <stdlib.h>
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#include <misc/balign.h>
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#include <misc/offset.h>
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#include <misc/byteorder.h>
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#include <security/BRandom.h>
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#include <security/BHash.h>
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#include "SPProtoEncoder.h"
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static int can_encode (SPProtoEncoder *o);
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static void encode_packet (SPProtoEncoder *o);
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static void encode_work_func (SPProtoEncoder *o);
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static void encode_work_handler (SPProtoEncoder *o);
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static void maybe_encode (SPProtoEncoder *o);
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static void output_handler_recv (SPProtoEncoder *o, uint8_t *data);
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static void input_handler_done (SPProtoEncoder *o, int data_len);
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static void handler_job_hander (SPProtoEncoder *o);
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static void otpgenerator_handler (SPProtoEncoder *o);
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static void maybe_stop_work (SPProtoEncoder *o);
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static int can_encode (SPProtoEncoder *o)
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{
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ASSERT(o->in_len >= 0)
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ASSERT(o->out_have)
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ASSERT(!o->tw_have)
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return (
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(!SPPROTO_HAVE_OTP(o->sp_params) || OTPGenerator_GetPosition(&o->otpgen) < o->sp_params.otp_num) &&
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(!SPPROTO_HAVE_ENCRYPTION(o->sp_params) || o->have_encryption_key)
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);
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}
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static void encode_packet (SPProtoEncoder *o)
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{
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ASSERT(o->in_len >= 0)
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ASSERT(o->out_have)
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ASSERT(!o->tw_have)
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ASSERT(can_encode(o))
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// generate OTP, remember seed ID
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if (SPPROTO_HAVE_OTP(o->sp_params)) {
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o->tw_seed_id = o->otpgen_seed_id;
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o->tw_otp = OTPGenerator_GetOTP(&o->otpgen);
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}
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// start work
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BThreadWork_Init(&o->tw, o->twd, (BThreadWork_handler_done)encode_work_handler, o, (BThreadWork_work_func)encode_work_func, o);
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o->tw_have = 1;
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// schedule OTP warning handler
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if (SPPROTO_HAVE_OTP(o->sp_params) && OTPGenerator_GetPosition(&o->otpgen) == o->otp_warning_count) {
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BPending_Set(&o->handler_job);
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}
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}
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static void encode_work_func (SPProtoEncoder *o)
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{
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ASSERT(o->in_len >= 0)
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ASSERT(o->out_have)
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ASSERT(!SPPROTO_HAVE_ENCRYPTION(o->sp_params) || o->have_encryption_key)
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ASSERT(o->in_len <= o->input_mtu)
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// determine plaintext location
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uint8_t *plaintext = (SPPROTO_HAVE_ENCRYPTION(o->sp_params) ? o->buf : o->out);
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// plaintext begins with header
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uint8_t *header = plaintext;
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// plaintext is header + payload
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int plaintext_len = SPPROTO_HEADER_LEN(o->sp_params) + o->in_len;
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// write OTP
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if (SPPROTO_HAVE_OTP(o->sp_params)) {
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struct spproto_otpdata header_otpd;
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header_otpd.seed_id = htol16(o->tw_seed_id);
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header_otpd.otp = o->tw_otp;
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memcpy(header + SPPROTO_HEADER_OTPDATA_OFF(o->sp_params), &header_otpd, sizeof(header_otpd));
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}
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// write hash
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if (SPPROTO_HAVE_HASH(o->sp_params)) {
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uint8_t *header_hash = header + SPPROTO_HEADER_HASH_OFF(o->sp_params);
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// zero hash field
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memset(header_hash, 0, o->hash_size);
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// calculate hash
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uint8_t hash[BHASH_MAX_SIZE];
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BHash_calculate(o->sp_params.hash_mode, plaintext, plaintext_len, hash);
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// set hash field
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memcpy(header_hash, hash, o->hash_size);
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}
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int out_len;
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if (SPPROTO_HAVE_ENCRYPTION(o->sp_params)) {
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// encrypting pad(header + payload)
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int cyphertext_len = balign_up((plaintext_len + 1), o->enc_block_size);
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// write padding
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plaintext[plaintext_len] = 1;
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for (int i = plaintext_len + 1; i < cyphertext_len; i++) {
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plaintext[i] = 0;
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}
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// generate IV
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BRandom_randomize(o->out, o->enc_block_size);
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// copy IV because BEncryption_Encrypt changes the IV
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uint8_t iv[BENCRYPTION_MAX_BLOCK_SIZE];
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memcpy(iv, o->out, o->enc_block_size);
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// encrypt
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BEncryption_Encrypt(&o->encryptor, plaintext, o->out + o->enc_block_size, cyphertext_len, iv);
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out_len = o->enc_block_size + cyphertext_len;
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} else {
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out_len = plaintext_len;
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}
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// remember length
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o->tw_out_len = out_len;
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}
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static void encode_work_handler (SPProtoEncoder *o)
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{
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ASSERT(o->in_len >= 0)
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ASSERT(o->out_have)
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ASSERT(o->tw_have)
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// free work
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BThreadWork_Free(&o->tw);
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o->tw_have = 0;
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// finish packet
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o->in_len = -1;
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o->out_have = 0;
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PacketRecvInterface_Done(&o->output, o->tw_out_len);
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}
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static void maybe_encode (SPProtoEncoder *o)
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{
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if (o->in_len >= 0 && o->out_have && !o->tw_have && can_encode(o)) {
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encode_packet(o);
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}
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}
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static void output_handler_recv (SPProtoEncoder *o, uint8_t *data)
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{
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ASSERT(o->in_len == -1)
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ASSERT(!o->out_have)
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ASSERT(!o->tw_have)
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DebugObject_Access(&o->d_obj);
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// remember output packet
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o->out_have = 1;
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o->out = data;
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// determine plaintext location
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uint8_t *plaintext = (SPPROTO_HAVE_ENCRYPTION(o->sp_params) ? o->buf : o->out);
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// schedule receive
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PacketRecvInterface_Receiver_Recv(o->input, plaintext + SPPROTO_HEADER_LEN(o->sp_params));
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}
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static void input_handler_done (SPProtoEncoder *o, int data_len)
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{
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ASSERT(data_len >= 0)
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ASSERT(data_len <= o->input_mtu)
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ASSERT(o->in_len == -1)
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ASSERT(o->out_have)
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ASSERT(!o->tw_have)
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DebugObject_Access(&o->d_obj);
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// remember input packet
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o->in_len = data_len;
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// encode if possible
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if (can_encode(o)) {
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encode_packet(o);
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}
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}
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static void handler_job_hander (SPProtoEncoder *o)
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{
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ASSERT(SPPROTO_HAVE_OTP(o->sp_params))
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DebugObject_Access(&o->d_obj);
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if (o->handler) {
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o->handler(o->user);
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return;
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}
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}
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static void otpgenerator_handler (SPProtoEncoder *o)
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{
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ASSERT(SPPROTO_HAVE_OTP(o->sp_params))
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DebugObject_Access(&o->d_obj);
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// remember seed ID
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o->otpgen_seed_id = o->otpgen_pending_seed_id;
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// possibly continue I/O
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maybe_encode(o);
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}
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static void maybe_stop_work (SPProtoEncoder *o)
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{
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// stop existing work
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if (o->tw_have) {
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BThreadWork_Free(&o->tw);
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o->tw_have = 0;
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}
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}
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int SPProtoEncoder_Init (SPProtoEncoder *o, PacketRecvInterface *input, struct spproto_security_params sp_params, int otp_warning_count, BPendingGroup *pg, BThreadWorkDispatcher *twd)
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{
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spproto_assert_security_params(sp_params);
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ASSERT(spproto_carrier_mtu_for_payload_mtu(sp_params, PacketRecvInterface_GetMTU(input)) >= 0)
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if (SPPROTO_HAVE_OTP(sp_params)) {
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ASSERT(otp_warning_count > 0)
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ASSERT(otp_warning_count <= sp_params.otp_num)
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}
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// init arguments
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o->input = input;
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o->sp_params = sp_params;
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o->otp_warning_count = otp_warning_count;
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o->twd = twd;
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// set no handlers
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o->handler = NULL;
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// calculate hash size
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if (SPPROTO_HAVE_HASH(o->sp_params)) {
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o->hash_size = BHash_size(o->sp_params.hash_mode);
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}
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// calculate encryption block and key sizes
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if (SPPROTO_HAVE_ENCRYPTION(o->sp_params)) {
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o->enc_block_size = BEncryption_cipher_block_size(o->sp_params.encryption_mode);
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o->enc_key_size = BEncryption_cipher_key_size(o->sp_params.encryption_mode);
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}
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// init otp generator
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if (SPPROTO_HAVE_OTP(o->sp_params)) {
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if (!OTPGenerator_Init(&o->otpgen, o->sp_params.otp_num, o->sp_params.otp_mode, o->twd, (OTPGenerator_handler)otpgenerator_handler, o)) {
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goto fail0;
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}
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}
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// have no encryption key
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if (SPPROTO_HAVE_ENCRYPTION(o->sp_params)) {
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o->have_encryption_key = 0;
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}
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// remember input MTU
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o->input_mtu = PacketRecvInterface_GetMTU(o->input);
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// calculate output MTU
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o->output_mtu = spproto_carrier_mtu_for_payload_mtu(o->sp_params, o->input_mtu);
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// init input
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PacketRecvInterface_Receiver_Init(o->input, (PacketRecvInterface_handler_done)input_handler_done, o);
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// have no input in buffer
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o->in_len = -1;
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// init output
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PacketRecvInterface_Init(&o->output, o->output_mtu, (PacketRecvInterface_handler_recv)output_handler_recv, o, pg);
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// have no output available
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o->out_have = 0;
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// allocate plaintext buffer
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if (SPPROTO_HAVE_ENCRYPTION(o->sp_params)) {
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int buf_size = balign_up((SPPROTO_HEADER_LEN(o->sp_params) + o->input_mtu + 1), o->enc_block_size);
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if (!(o->buf = (uint8_t *)malloc(buf_size))) {
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goto fail1;
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}
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}
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// init handler job
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BPending_Init(&o->handler_job, pg, (BPending_handler)handler_job_hander, o);
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// have no work
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o->tw_have = 0;
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DebugObject_Init(&o->d_obj);
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return 1;
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fail1:
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PacketRecvInterface_Free(&o->output);
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if (SPPROTO_HAVE_OTP(o->sp_params)) {
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OTPGenerator_Free(&o->otpgen);
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}
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fail0:
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return 0;
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}
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void SPProtoEncoder_Free (SPProtoEncoder *o)
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{
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DebugObject_Free(&o->d_obj);
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// free work
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if (o->tw_have) {
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BThreadWork_Free(&o->tw);
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}
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// free handler job
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BPending_Free(&o->handler_job);
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// free plaintext buffer
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if (SPPROTO_HAVE_ENCRYPTION(o->sp_params)) {
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free(o->buf);
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}
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// free output
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PacketRecvInterface_Free(&o->output);
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// free encryptor
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if (SPPROTO_HAVE_ENCRYPTION(o->sp_params) && o->have_encryption_key) {
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BEncryption_Free(&o->encryptor);
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}
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// free otp generator
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if (SPPROTO_HAVE_OTP(o->sp_params)) {
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OTPGenerator_Free(&o->otpgen);
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}
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}
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PacketRecvInterface * SPProtoEncoder_GetOutput (SPProtoEncoder *o)
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{
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DebugObject_Access(&o->d_obj);
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return &o->output;
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}
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void SPProtoEncoder_SetEncryptionKey (SPProtoEncoder *o, uint8_t *encryption_key)
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{
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ASSERT(SPPROTO_HAVE_ENCRYPTION(o->sp_params))
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DebugObject_Access(&o->d_obj);
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// stop existing work
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maybe_stop_work(o);
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// free encryptor
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if (o->have_encryption_key) {
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BEncryption_Free(&o->encryptor);
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}
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// init encryptor
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BEncryption_Init(&o->encryptor, BENCRYPTION_MODE_ENCRYPT, o->sp_params.encryption_mode, encryption_key);
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// have encryption key
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o->have_encryption_key = 1;
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// possibly continue I/O
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maybe_encode(o);
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}
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void SPProtoEncoder_RemoveEncryptionKey (SPProtoEncoder *o)
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{
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ASSERT(SPPROTO_HAVE_ENCRYPTION(o->sp_params))
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DebugObject_Access(&o->d_obj);
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// stop existing work
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maybe_stop_work(o);
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if (o->have_encryption_key) {
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// free encryptor
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BEncryption_Free(&o->encryptor);
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// have no encryption key
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o->have_encryption_key = 0;
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}
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}
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void SPProtoEncoder_SetOTPSeed (SPProtoEncoder *o, uint16_t seed_id, uint8_t *key, uint8_t *iv)
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{
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ASSERT(SPPROTO_HAVE_OTP(o->sp_params))
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DebugObject_Access(&o->d_obj);
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// give seed to OTP generator
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OTPGenerator_SetSeed(&o->otpgen, key, iv);
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// remember seed ID
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o->otpgen_pending_seed_id = seed_id;
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}
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void SPProtoEncoder_RemoveOTPSeed (SPProtoEncoder *o)
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{
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ASSERT(SPPROTO_HAVE_OTP(o->sp_params))
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DebugObject_Access(&o->d_obj);
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// reset OTP generator
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OTPGenerator_Reset(&o->otpgen);
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}
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|
void SPProtoEncoder_SetHandlers (SPProtoEncoder *o, SPProtoEncoder_handler handler, void *user)
|
||
|
{
|
||
|
DebugObject_Access(&o->d_obj);
|
||
|
|
||
|
o->handler = handler;
|
||
|
o->user = user;
|
||
|
}
|