Previously a new goroutine was launched for each notification in order to
avoid blocking chain from continuing while the notification is being
processed. This approach had a couple of issues.
First, since goroutines are not guaranteed to execute in any given order,
the notifications were no longer handled in the same order as they were
sent. For the current code, this is not a problem, but upcoming code that
handles a transaction memory pool, the order needs to be correct.
Second, goroutines are relatively cheap, but it's still quite a bit of
overhead to launch 3-4 goroutines per block.
This commit modifies the handling code to have a single sink executing in
a separate goroutine. The main handler then adds the notifications to a
queue which is processed by the sink. This approach retains the
non-blocking behavior of the previous approach, but also keeps the order
correct and, as an additional benefit, is also more efficient.
This removes a horrible case of reach-around from per into the guts of
the blockmaanger to frob the chain. Soon, when we try to deduplicate the
fetching of blocks from multiple peers this will need decisions made in
a central point.
Discussed at length with davec.
This commit adds detection and filtering for back-to-back duplicate
getblocks requests. This is needed because the trigger for requesting
more blocks is receiving an orphan. When the peer is further behind than
the number of blocks advertised via a single inventory message, the same
orphan block will be sent multiple times. When the peer receives the
final inventory message, it too contains the orphan that was previously
sent. This leads to a duplicate getblocks request that must be filtered
to prevent requesting the final series of blocks again.
This commit adds environment variable expansion and path cleaning to the
data directory. This allows the user to specify data paths in the config
file such as datadir=~/.btcd/data and datadir=$SOMEVAR/btcd. It also
adds usage instructions and an example to the sample btcd.conf file.
- Remove leftover debug log prints
- Increment waitgroup outside of goroutine
- Various comment and log message consistency
- Combine peer setup and newPeer -> newInboundPeer
- Save and load peers.json to/from cfg.DataDir
- Only claim addrmgr needs more addresses when it has less than 1000
- Add warning if unkown peer on orphan block.
Use it to add multiple peer support. We try and keep 8 outbound peers
active at all times.
This address manager is not as complete as the one in bitcoind yet, but
additional functionality is being worked on.
We currently handle (in a similar manner to bitcoind):
- biasing between new and already tried addresses based on number of connected
peers.
- rejection of non-default ports until desparate
- address selection probabilities based on last successful connection and number
of failures.
- routability checks based on known unroutable subnets.
- only connecting to each network `group' once at any one time.
We currently lack support for:
- tor ``addresses'' (an .onion address encoded in 64 bytes of ip address)
- full state save and restore (we just save a json with the list of known
addresses in it)
- multiple buckets for new and tried addresses selected by a hash of address and
source. The current algorithm functions the same as bitcoind would with only
one bucket for new and tried (making the address cache rather smaller than it
otherwise would be).
The regression test mode is special in that the 'official' block test
suite requires an empty database to work properly. Rather than having to
manual go delete it before each test, add code to automatically delete the
old regression test database when in regression test mode.
This commit modifies the way the data paths are handled. Since there will
ultimately be more data associated with each network than just the block
database, the data path has been modified to be "namespaced" based on the
network. This allows all data associated with a specific network to
simply use the data path without having to worry about conflicts with data
from other networks.
In addition, this commit renames the block database to "blocks" plus a
suffix which denotes the database type. This prevents issues that would
otherwise arise if the user decides to use a different database type and
a file/folder with the same name already eixsts but is of the old database
type. For most users this won't matter, but it does provide nice
properties for testing and development as well since it makes it easy to
go back and forth between database types.
This commit also includes code to upgrade the old database paths to the
new ones so the change is seamless for the user.
Finally, bump the version to 0.2.0.
This commit adds a basic infrastructure to allow upgrades to happen to
btcd as needed. This paves the way for the upcoming data path changes to
be automatically updated for the user as needed and also ensures any
future changes that might require upgrades already have an established
way of performing the needed upgrades.
This change paves the way for saving more than just the block database to
the filesystem (such as address manager data, index data, etc) where the
name "dbdir" no longer makes sense.
This commit changes the code so that all calls to .Add on waitgroups
happen before the associated goroutines are launched. Doing this after
the goroutine could technically cause a race where the goroutine started
and finished before the main goroutine has a chance to increment the
counter. In our particular case none of the goroutines exit quickly
enough for this to be an issue, but nevertheless the correct way should be
used.
This commit adds support for relaying blocks between peers. It keeps
track of inventory that has either already been advertised to remote peers
or advertised by remote peers using a size-limited most recently used
cache. This helps avoid relaying inventory the peer already knows as
much as possible while not allowing rogue peers to eat up arbitrary
amounts of memory with bogus inventory.
This commit reworks the getblocks handling a bit to clean it up and match
the reference implementation handling. In particular, it adds monitoring
for when peers request the final block advertised from a previous
getblocks message and automatically avertises the latest known block
inventory to trigger the peer to send another getblocks message.
When no blocks in the block locator are found, start with the block after
the genesis block. This means the client will start over with the genesis
block if unknown block locators are provided. This mirrors the behavior
in the reference implementation.
This commit reworks the getheaders handling a bit to clean it up and match
the reference implementation handling. In particular, in addition to the
normal handling where headers starting after the block locator up to the
stop hash are served, when no locator hashes are provided, the stop hash
acts as a way to specifically request that header. Next, an empty headers
message is sent when no hashes provided by the block locator can be
found. Finally, there was a bug that was limiting the number of headers
that could requested at once to 500 instead of the expected 2000.
Rather than only setting the services field for inbound peers, set it for
all peers. This field referes to the remote peer's services regardless of
inbound or outbound.
This commit significantly reworks the fetching code to interop better with
bitcoind. In particular, when an inventory message is sent, and the
remote peer requests the final block, the remote peer sends the current
end of the main chain to signal that there are more blocks to get.
Previously this code was automatically requesting more blocks when the
number of in-flight blocks was under a certain threshold. The original
approach does help alleviate delays in the "request final, wait for
orphan, request more" round trip, but due to the aforementioned mechanism,
it leads to double requests and other subtle issues.
When running in regression test mode, it is unlikely the user wants to
connect to permanent peers they have configured in their config file.
This commit modifies the code to ignore the config file entry when in
regression test mode. The user can still provide -a (or --addpeer) on the
command line to override this if they really want to connect out to a
specific peer during regression test mode.
This commit modifies the input message handler so that when a remote peer
sends a block, no further messages from that peer are accepted until the
block has been fully processed and therefore known good or bad. This
helps prevent a malicious peer from queueing up a bunch of bad blocks
before disconnecting (or being disconnected) and wasting memory.
Additionally, this behavior is depended on by at least the block
acceptance test tool as the reference implementation processes blocks in
the same thread and therefore blocks further messages until the block has
been fully processed as well.
