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- #!@PYTHON@
- # This file is part of GNUnet
- # (C) 2013, 2018 Christian Grothoff (and other contributing authors)
- #
- # GNUnet is free software: you can redistribute it and/or modify it
- # under the terms of the GNU Affero General Public License as published
- # by the Free Software Foundation, either version 3 of the License,
- # or (at your option) any later version.
- #
- # GNUnet is distributed in the hope that it will be useful, but
- # WITHOUT ANY WARRANTY; without even the implied warranty of
- # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- # Affero General Public License for more details.
- #
- # You should have received a copy of the GNU Affero General Public License
- # along with this program. If not, see <http://www.gnu.org/licenses/>.
- #
- # SPDX-License-Identifier: AGPL3.0-or-later
- import argparse
- import random
- from math import ceil, log, floor
- def bsc(n):
- """ count the bits set in n"""
- l = n.bit_length()
- c = 0
- x = 1
- for _ in range(0, l):
- if n & x:
- c = c + 1
- x = x << 1
- return c
- def simulate(k, n, verbose):
- assert k < n
- largest_arc = int(2**ceil(log(n, 2))) // 2
- num_ghosts = (2 * largest_arc) - n
- if verbose:
- print("we have", num_ghosts, "ghost peers")
- # n.b. all peers with idx<k are evil
- peers = list(range(n))
- info = [1 << x for x in range(n)]
- def done_p():
- for x in range(k, n):
- if bsc(info[x]) < n-k:
- return False
- return True
- rounds = 0
- while not done_p():
- if verbose:
- print("-- round --")
- arc = 1
- while arc <= largest_arc:
- if verbose:
- print("-- subround --")
- new_info = [x for x in info]
- for peer_physical in range(n):
- peer_logical = peers[peer_physical]
- peer_type = None
- partner_logical = (peer_logical + arc) % n
- partner_physical = peers.index(partner_logical)
- if peer_physical < k or partner_physical < k:
- if verbose:
- print("bad peer in connection", peer_physical, "--", partner_physical)
- continue
- if peer_logical & arc == 0:
- # we are outgoing
- if verbose:
- print(peer_physical, "connects to", partner_physical)
- peer_type = "outgoing"
- if peer_logical < num_ghosts:
- # we have a ghost, check if the peer who connects
- # to our ghost is actually outgoing
- ghost_partner_logical = (peer_logical - arc) % n
- if ghost_partner_logical & arc == 0:
- peer_type = peer_type + ", ghost incoming"
- new_info[peer_physical] = new_info[peer_physical] | info[peer_physical] | info[partner_physical]
- new_info[partner_physical] = new_info[partner_physical] | info[peer_physical] | info[partner_physical]
- else:
- peer_type = "incoming"
- if verbose > 1:
- print("type of", str(peer_physical) + ":", peer_type)
- info = new_info
- arc = arc << 1
- rounds = rounds + 1
- random.shuffle(peers)
- return rounds
- if __name__ == "__main__":
- parser = argparse.ArgumentParser()
- parser.add_argument("k", metavar="k", type=int, help="#(bad peers)")
- parser.add_argument("n", metavar="n", type=int, help="#(all peers)")
- parser.add_argument("r", metavar="r", type=int, help="#(rounds)")
- parser.add_argument('--verbose', '-v', action='count')
- args = parser.parse_args()
- sum = 0.0
- for n in range(0, args.r):
- sum += simulate(args.k, args.n, args.verbose)
- print(sum // args.r)
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