f4932d94c0
The hash is not needed since the sellers application is required to sign the description and the bidders application is required to check the signature. Since the arbitrary description used by the application was only used inside this hash, it can be removed as well.
469 lines
14 KiB
C
469 lines
14 KiB
C
/* This file is part of libbrandt.
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* Copyright (C) 2016 GNUnet e.V.
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*
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* libbrandt is free software: you can redistribute it and/or modify it under
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* the terms of the GNU General Public License as published by the Free Software
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* Foundation, either version 3 of the License, or (at your option) any later
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* version.
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*
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* libbrandt is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
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* A PARTICULAR PURPOSE. See the GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along with
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* libbrandt. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @file brandt.c
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* @brief Implementation of the high level libbrandt interface.
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* @author Markus Teich
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*/
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#include "platform.h"
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#include "crypto.h"
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#include "internals.h"
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#include "util.h"
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void
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BRANDT_init (struct GNUNET_CRYPTO_EccDlogContext *dlogctx)
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{
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gcry_error_t err = 0;
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if (!gcry_check_version ("1.7.0"))
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eprintf ("libgcrypt version mismatch");
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/* SECMEM cannot be resized dynamically. We do not know how much we need */
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if ((err = gcry_control (GCRYCTL_DISABLE_SECMEM, 0)))
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weprintf ("failed to set libgcrypt option DISABLE_SECMEM: %s",
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gcry_strerror (err));
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/* ecc is slow otherwise and we don't create long term keys anyway. */
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if ((err = gcry_control (GCRYCTL_ENABLE_QUICK_RANDOM, 0)))
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weprintf ("failed to set libgcrypt option ENABLE_QUICK_RANDOM: %s",
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gcry_strerror (err));
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gcry_control (GCRYCTL_INITIALIZATION_FINISHED, 0);
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brandt_crypto_init (dlogctx);
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}
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void
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BRANDT_bidder_start (struct BRANDT_Auction *auction,
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uint16_t i,
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uint16_t n)
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{
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enum auction_type atype;
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enum outcome_type outcome;
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unsigned char *buf;
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size_t buflen;
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GNUNET_assert (auction && n > 0 && i < n);
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auction->n = n;
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auction->i = i;
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atype = auction->m > 0 ? auction_mPlusFirstPrice : auction_firstPrice;
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outcome = auction->outcome_public ? outcome_public : outcome_private;
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if (auction_mPlusFirstPrice == atype && n <= auction->m)
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{ /* fewer bidders than items to sell. every bidder won with lowest price */
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struct BRANDT_Result *res;
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if (auction->outcome_public)
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{
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res = GNUNET_new_array (n, struct BRANDT_Result);
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for (uint16_t h = 0; h < n; h++)
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{
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res[h].bidder = h;
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res[h].price = 0;
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res[h].status = BRANDT_bidder_won;
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}
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auction->result (auction->closure, res, n);
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}
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else
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{
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res = GNUNET_new (struct BRANDT_Result);
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res->bidder = i;
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res->price = 0;
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res->status = BRANDT_bidder_won;
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auction->result (auction->closure, res, 1);
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}
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return;
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}
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/* On M+1st price auctions we multiply the amount of prizes by the amount of
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* bidders and resctrict each bidder to his own distinct subset of the
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* prices. This is done for tie breaking. An additional proof is used in the
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* encrypt_bid round to show that the bidder has chosen a valid bid and the
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* outcome callback will remap the result to the original k price values. */
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if (auction_mPlusFirstPrice == atype)
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{
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auction->k *= n;
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auction->b = auction->b * n + n - i - 1;
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}
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if (handler_prep[atype][outcome][msg_init])
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handler_prep[atype][outcome][msg_init] (auction);
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if (!handler_out[atype][outcome][msg_init] ||
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!(buf = handler_out[atype][outcome][msg_init](auction, &buflen)))
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{
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/** \todo */
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weprintf ("wow fail out");
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return;
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}
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auction->bcast (auction->closure, buf, buflen);
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gcry_mpi_set_bit (auction->round_progress, auction->i);
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free (buf);
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}
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static void
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seller_start (void *arg)
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{
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struct BRANDT_Auction *ad = (struct BRANDT_Auction *)arg;
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enum auction_type atype;
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enum outcome_type outcome;
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ad->task = NULL;
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ad->n = ad->start (ad->closure);
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if (0 == ad->n)
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{
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weprintf ("no bidders registered for auction");
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ad->result (ad->closure, NULL, 0);
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return;
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}
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else if (ad->n <= ad->m)
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{
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struct BRANDT_Result *res = GNUNET_new_array (ad->n,
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struct BRANDT_Result);
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weprintf ("less bidders than needed, selling for lowest price");
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for (uint16_t i = 0; i < ad->n; i++)
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{
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res[i].bidder = i;
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res[i].price = 0;
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res[i].status = BRANDT_bidder_won;
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}
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ad->result (ad->closure, res, ad->n);
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}
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atype = ad->m > 0 ? auction_mPlusFirstPrice : auction_firstPrice;
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outcome = ad->outcome_public ? outcome_public : outcome_private;
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/* On M+1st price auctions we multiply the amount of prizes by the amount of
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* bidders and resctrict each bidder to his own distinct subset of the
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* prices. This is done for tie breaking. An additional proof is used in the
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* encrypt_bid round to show that the bidder has chosen a valid bid and the
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* outcome callback will remap the result to the original k price values. */
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if (auction_mPlusFirstPrice == atype)
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ad->k *= ad->n;
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if (handler_prep[atype][outcome][msg_init])
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handler_prep[atype][outcome][msg_init] (ad);
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}
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struct BRANDT_Auction *
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BRANDT_new (BRANDT_CbResult result,
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BRANDT_CbBroadcast broadcast,
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BRANDT_CbStart start,
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void *auction_closure,
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void **auction_desc,
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size_t *auction_desc_len,
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struct GNUNET_TIME_Absolute time_start,
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struct GNUNET_TIME_Relative time_round,
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uint16_t num_prices,
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uint16_t m,
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int outcome_public)
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{
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struct BRANDT_Auction *ret;
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struct BRANDT_DescrP *desc;
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struct GNUNET_TIME_Relative until_start;
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if (0 == num_prices)
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return NULL;
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desc = GNUNET_new (struct BRANDT_DescrP);
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desc->time_start = GNUNET_TIME_absolute_hton (time_start);
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desc->time_round = GNUNET_TIME_relative_hton (time_round);
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desc->k = htons (num_prices);
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desc->m = htons (m);
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desc->outcome_public = htons (outcome_public);
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ret = GNUNET_new (struct BRANDT_Auction);
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ret->time_start = time_start;
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ret->time_round = time_round;
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ret->k = num_prices;
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ret->m = m;
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ret->outcome_public = outcome_public;
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ret->cur_round = msg_init;
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ret->round_progress = gcry_mpi_new (256);
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/* we are the seller */
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ret->seller_mode = 1;
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/* callback interface with application */
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ret->closure = auction_closure;
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ret->bcast = broadcast;
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ret->result = result;
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ret->start = start;
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until_start = GNUNET_TIME_absolute_get_remaining (time_start);
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ret->task = GNUNET_SCHEDULER_add_delayed (until_start,
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&seller_start,
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ret);
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*auction_desc_len = sizeof (struct BRANDT_DescrP);
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*auction_desc = desc;
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return ret;
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}
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int
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BRANDT_parse_desc (const void *auction_desc,
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size_t auction_desc_len,
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struct GNUNET_TIME_Absolute *time_start,
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struct GNUNET_TIME_Relative *time_round,
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uint16_t *num_prices,
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uint16_t *m,
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uint16_t *outcome_public)
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{
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const struct BRANDT_DescrP *desc = auction_desc;
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const uint32_t zero = 0;
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if (sizeof (struct BRANDT_DescrP) != auction_desc_len)
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{
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weprintf ("auction desc struct size mismatch");
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return -1;
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}
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if (0 != memcmp (&desc->reserved, &zero, sizeof (desc->reserved)))
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{
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weprintf ("reserved field in auction description must be zero");
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return -1;
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}
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if (time_start)
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*time_start = GNUNET_TIME_absolute_ntoh (desc->time_start);
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if (time_round)
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*time_round = GNUNET_TIME_relative_ntoh (desc->time_round);
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if (num_prices)
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*num_prices = ntohs (desc->k);
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if (m)
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*m = ntohs (desc->m);
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if (outcome_public)
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*outcome_public = ntohs (desc->outcome_public);
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return 0;
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}
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struct BRANDT_Auction *
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BRANDT_join (BRANDT_CbResult result,
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BRANDT_CbBroadcast broadcast,
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BRANDT_CbUnicast unicast,
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void *auction_closure,
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const void *auction_desc,
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size_t auction_desc_len,
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uint16_t bid)
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{
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struct BRANDT_Auction *ret = GNUNET_new (struct BRANDT_Auction);
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if (0 != BRANDT_parse_desc (auction_desc,
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auction_desc_len,
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&ret->time_start,
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&ret->time_round,
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&ret->k,
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&ret->m,
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&ret->outcome_public))
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{
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GNUNET_free (ret);
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weprintf ("failed to parse auction description blob");
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return NULL;
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}
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ret->cur_round = msg_init;
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ret->round_progress = gcry_mpi_new (256);
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ret->b = bid;
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/* we are the seller */
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ret->seller_mode = 0;
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/* callback interface with application */
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ret->closure = auction_closure;
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ret->bcast = broadcast;
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ret->ucast = unicast;
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ret->result = result;
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return ret;
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}
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void
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BRANDT_destroy (struct BRANDT_Auction *auction)
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{
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if (auction->task)
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GNUNET_SCHEDULER_cancel (auction->task);
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gcry_mpi_release (auction->round_progress);
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gcry_mpi_release (auction->x);
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smc_free1 (auction->y, auction->n);
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gcry_mpi_point_release (auction->Y);
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smc_free2 (auction->alpha, auction->n, auction->k);
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smc_free2 (auction->beta, auction->n, auction->k);
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smc_free2 (auction->gamma2, auction->n, auction->k);
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smc_free2 (auction->delta2, auction->n, auction->k);
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smc_free2 (auction->phi2, auction->n, auction->k);
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free (auction->phiproofs3);
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smc_free1 (auction->tmpa1, auction->k);
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smc_free1 (auction->tmpb1, auction->k);
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if (auction->m > 0 && auction->outcome_public)
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{
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smc_free3 (auction->gamma3, auction->n, 2, auction->k);
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smc_free3 (auction->delta3, auction->n, 2, auction->k);
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smc_free3 (auction->phi3, auction->n, 2, auction->k);
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}
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else
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{
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smc_free3 (auction->gamma3, auction->n, auction->n, auction->k);
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smc_free3 (auction->delta3, auction->n, auction->n, auction->k);
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smc_free3 (auction->phi3, auction->n, auction->n, auction->k);
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}
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}
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static void
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report_outcome (struct BRANDT_Auction *ad,
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enum auction_type atype,
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enum outcome_type outcome)
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{
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struct BRANDT_Result *res;
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uint16_t reslen = 0;
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if (!handler_res[atype][outcome] ||
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!(res = handler_res[atype][outcome] (ad, &reslen)))
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ad->result (ad->closure, NULL, 0);
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else
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ad->result (ad->closure, res, reslen);
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}
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static void
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advance_round (struct BRANDT_Auction *ad,
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enum auction_type atype,
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enum outcome_type outcome)
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{
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unsigned char *buf;
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size_t buflen;
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if (!ad->seller_mode && msg_decrypt == ad->cur_round && !outcome)
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{
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/* we are a bidder on a private outcome auction and
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* successfully parsed the msg_decrypt from the seller
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* => we can determine the auction result */
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report_outcome (ad, atype, outcome);
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return;
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}
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/* only continue if the round is complete */
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for (uint16_t i = 0; i < ad->n; i++)
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if (!gcry_mpi_test_bit (ad->round_progress, i))
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return;
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if (ad->seller_mode && msg_decrypt == ad->cur_round && !ad->outcome_public)
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{
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/* all bidders msg_decrypt received, broadcast combined msg_decrypt */
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if (!handler_out[atype][outcome][ad->cur_round] ||
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!(buf = handler_out[atype][outcome][ad->cur_round](ad, &buflen)))
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{
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weprintf ("failed to create msg %d buffer as seller",
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ad->cur_round);
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return;
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}
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ad->bcast (ad->closure, buf, buflen);
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}
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if (msg_decrypt == ad->cur_round)
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{
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report_outcome (ad, atype, outcome);
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return;
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}
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/* round complete, advance to next one */
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gcry_mpi_clear_highbit (ad->round_progress, 0);
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ad->cur_round++;
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/* prepare next round. */
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if (handler_prep[atype][outcome][ad->cur_round])
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handler_prep[atype][outcome][ad->cur_round] (ad);
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if (ad->seller_mode)
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{
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/** \todo: setup round timeout trigger */
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/* seller does not send regular messages */
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return;
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}
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/* create next message buffer */
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if (!handler_out[atype][outcome][ad->cur_round] ||
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!(buf = handler_out[atype][outcome][ad->cur_round](ad, &buflen)))
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{
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weprintf ("failed to create msg %d buffer as bidder", ad->cur_round);
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return;
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}
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/* msg_decrypt unicast to seller if private outcome mode.
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* All other messages are broadcasted */
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if (msg_decrypt == ad->cur_round && !outcome)
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ad->ucast (ad->closure, buf, buflen);
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else
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ad->bcast (ad->closure, buf, buflen);
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gcry_mpi_set_bit (ad->round_progress, ad->i);
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}
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void
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BRANDT_got_message (struct BRANDT_Auction *auction,
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uint16_t sender,
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const unsigned char *msg,
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size_t msg_len)
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{
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struct msg_head *head = (struct msg_head *)msg;
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enum auction_type atype;
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enum outcome_type outcome;
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enum rounds round = auction->cur_round;
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atype = auction->m > 0 ? auction_mPlusFirstPrice : auction_firstPrice;
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outcome = auction->outcome_public ? outcome_public : outcome_private;
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/** \todo: cache out of order messages instead of discarding */
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if (ntohl (head->msg_type) != round || ntohl (head->prot_version) != 0)
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{
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weprintf ("got unexpected message, ignoring...");
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return;
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}
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/* check if we already got that round message from the same user */
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if (gcry_mpi_test_bit (auction->round_progress, sender))
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{
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weprintf ("got a duplicate message from user %d", sender);
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return;
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}
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if (!handler_in[atype][outcome][round] ||
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!handler_in[atype][outcome][round](auction,
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msg + sizeof (*head),
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msg_len - sizeof (*head),
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sender))
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{
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/** \todo */
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weprintf ("wow fail in");
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return;
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}
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gcry_mpi_set_bit (auction->round_progress, sender);
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advance_round (auction, atype, outcome);
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}
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