Design goals:
* Only keep a limited number of addresses around, so that addr.dat does not grow without bound.
* Keep the address tables in-memory, and occasionally write the table to addr.dat.
* Make sure no (localized) attacker can fill the entire table with his nodes/addresses.
See comments in addrman.h for more detailed information.
This also avoids flushing setAddrKnown until 24 hours has passed,
and avoids contacting the external IP services when not listening.
Advertising non-listening nodes is just addr message spam.
It doesn't help the network, in fact it hurts the network,
and it also hurts user's privacy.
Advertising far out of sync nodes doesn't help the network—
they can't even forward (most) transactions and wastes nodes
outbound slots.
Allow mining of min-difficulty blocks if 20 minutes have gone by without mining a regular-difficulty block.
Normal rules apply every 2016 blocks, though, so there may be a very-slow-to-confirm block at the difficulty-adjustment blocks.
This also removes an un-needed sigops-per-byte check when accepting transactions to the memory pool (un-needed assuming only standard transactions are being accepted). And it only counts P2SH sigops after the switchover date.
This introduces CNetAddr and CService, respectively wrapping an
(IPv6) IP address and an IP+port combination. This functionality used
to be part of CAddress, which also contains network flags and
connection attempt information. These extra fields are however not
always necessary.
These classes, along with logic for creating connections and doing
name lookups, are moved to netbase.{h,cpp}, which does not depend on
headers.h.
Furthermore, CNetAddr is mostly IPv6-ready, though IPv6
functionality is not yet enabled for the application itself.
so it takes a flag for how to interpret OP_EVAL.
Also increased IsStandard size of scriptSigs to 500 bytes, so
a 3-of-3 multisig transaction IsStandard.
OP_EVAL is a new opcode that evaluates an item on the stack as a script.
It enables a new type of bitcoin address that needs an arbitrarily
complex script to redeem.
During the rushed transition from 0.01 BTC to 0.0005 BTC fees, we took the
approach of dropping the relay and block-inclusion fee to 0.0005 BTC
immediately, and only delayed adjusting the sending fee for the next release.
Afterward, the relay fee was lowered to 0.0001 BTC to avoid having the same
problem in the future. However, the block inclusion code was left setting
fForRelay to true! This fixes that, so the lower 0.0001 BTC allowance is (as
intended) only permitted for real relaying.
getmemorypool [data]
If [data] is not specified, returns data needed to construct a block to work on:
"version" : block version
"previousblockhash" : hash of current highest block
"transactions" : contents of non-coinbase transactions that should be included in the next block
"coinbasevalue" : maximum allowable input to coinbase transaction, including the generation award and transaction fees
"time" : timestamp appropriate for next block
"bits" : compressed target of next block
If [data] is specified, tries to solve the block and returns true if it was successful.
Pieter Wuille