Previously the getnettotals was just looping through all of the currently
connected peers to sum the byte counts and returning that. However, the
intention of the getnettotals RPC is to get all bytes since the server was
started, so this logic was not correct.
This commit modifies the code to keep an atomic counter on the server for
bytes read/written and has each peer update the server counters as well as
the per-peer counters.
Rather than using a dedicated channel for the sync peer request and reply,
use a single query channel that accepts a query type as well as a reply
channel. This will allow other queries to be added in the future without
the various queries being racy.
This commit adds byte counters to each peer using the new btcwire
ReadMessageN and WriteMessageN functions to obtain the number of bytes
read and written, respectively. It also returns those byte counters via
the PeerInfo struct which is used to populate the RPC getpeerinfo reply.
Closes#83.
This commit moves the connection endpoint for websockets to /ws instead of
/wallet. First, the former is more standard, and second the latter
presumes how the websocket is to be used.
Closes#80.
This commit improves how the headers-first mode works in several ways.
The previous headers-first code was an initial implementation that did not
have all of the bells and whistles and a few less than ideal
characteristics. This commit improves the heaers-first code to resolve
the issues discussed next.
- The previous code only used headers-first mode when starting out from
block height 0 rather than allowing it to work starting at any height
before the final checkpoint. This means if you stopped the chain
download at any point before the final checkpoint and restarted, it
would not resume and you therefore would not have the benefit of the
faster processing offered by headers-first mode.
- Previously all headers (even those after the final checkpoint) were
downloaded and only the final checkpoint was verified. This resulted in
the following issues:
- As the block chain grew, increasingly larger numbers of headers were
downloaded and kept in memory
- If the node the node serving up the headers was serving an invalid
chain, it wouldn't be detected until downloading a large number of
headers
- When an invalid checkpoint was detected, no action was taken to
recover which meant the chain download would essentially be stalled
- The headers were kept in memory even though they didn't need to be as
merely keeping track of the hashes and heights is enough to provde they
properly link together and checkpoints match
- There was no logging when headers were being downloaded so it could
appear like nothing was happening
- Duplicate requests for the same headers weren't being filtered which
meant is was possible to inadvertently download the same headers twice
only to throw them away.
This commit resolves these issues with the following changes:
- The current height is now examined at startup and prior each sync peer
selection to allow it to resume headers-first mode starting from the
known height to the next checkpoint
- All checkpoints are now verified and the headers are only downloaded
from the current known block height up to the next checkpoint. This has
several desirable properties:
- The amount of memory required is bounded by the maximum distance
between to checkpoints rather than the entire length of the chain
- A node serving up an invalid chain is detected very quickly and with
little work
- When an invalid checkpoint is detected, the headers are simply
discarded and the peer is disconnected for serving an invalid chain
- When the sync peer disconnets, all current headers are thrown away
and, due to the new aforementioned resume code, when a new sync peer
is selected, headers-first mode will continue from the last known good
block
- In addition to reduced memory usage from only keeping information about
headers between two checkpoints, the only information now kept in memory
about the headers is the hash and height rather than the entire header
- There is now logging information about what is happening with headers
- Duplicate header requests are now filtered
Previously the logging function which reports on progress was called for
every block, regardless of whether it was an orphan or not. This could be
confusing since it could show a different number of blocks processed as
compared to the old versus new heights reported (orphans do not add to the
block height since they aren't extending the main chain). Further, the
database had to be consulted for the latest block since the block we just
processed might not be the latest one if it was an orphan. This is quite
a bit more time conusming than it should've been for progress reporting.
This commit modifies that to only include non-orphan blocks. As a result,
the latest height shown will match the number of blocks processed (even
when there are orphans) and the additional block lookup from the database
is avoided.
