Bitcoin will not make an outbound connection to a network group
(/16 for IPv4) that it is already connected to. This means that
if an attacker wants good odds of capturing all a nodes outbound
connections he must have hosts on a a large number of distinct
groups.
Previously both inbound and outbound connections were used to
feed this exclusion. The use of inbound connections, which can be
controlled by the attacker, actually has the potential of making
sibyl attacks _easier_: An attacker can start up hosts in groups
which house many honest nodes and make outbound connections to
the victim to exclude big swaths of honest nodes. Because the
attacker chooses to make the outbound connection he can always
beat out honest nodes for the consumption of inbound slots.
At _best_ the old behavior increases attacker costs by a single
group (e.g. one distinct group to use to fill up all your inbound
slots), but at worst it allows the attacker to select whole
networks you won't connect to.
This commit makes the nodes use only outbound links to exclude
network groups for outbound connections. Fancier things could
be done, like weaker exclusion for inbound groups... but
simplicity is good and I don't believe more complexity is
currently needed.
Useful for developers who need to refer to futher back in debug.log history, but who don't want to
enable the -debug option and all the verbosity that comes with that.
- display as "language - country (locale name)", when locale name consists of 2 parts
- display as "language (locale name)", when locale name consists of 1 part
Use Boost's signal2 slot tracking mechanism to cancel any (still open)
listening sockets when receiving a shutdown signal.
Signed-off-by: Giel van Schijndel <me@mortis.eu>
This commit adds support for .onion addresses (mapped into the IPv6
by using OnionCat's range and encoding), and the ability to connect
to them via a SOCKS5 proxy.
Prior to this change, each TX typically generated 3+ debug messages,
askfor tx 8644cc97480ba1537214 0
sending getdata: tx 8644cc97480ba1537214
askfor tx 8644cc97480ba1537214 1339640761000000
askfor tx 8644cc97480ba1537214 1339640881000000
CTxMemPool::accept() : accepted 8644cc9748 (poolsz 6857)
After this change, there is only one message for each valid TX received
CTxMemPool::accept() : accepted 22a73c5d8c (poolsz 42)
and two messages for each orphan tx received
ERROR: FetchInputs() : 673dc195aa mempool Tx prev not found 1e439346fc
stored orphan tx 673dc195aa (mapsz 19)
The -debugnet option, or its superset -debug, will restore the full debug
output.
Since the minimum signed integer cannot be represented as positive so long as its type is signed, and it's not well-defined what happens if you make it unsigned before negating it, we instead increment the negative integer by 1, convert it, then increment the (now positive) unsigned integer by 1 to compensate
Gregory Maxwell