zcashd/doc/release-notes/release-notes-4.3.0.md

Notable changes

Reduce download traffic

We have made several changes to reduce the amount of data downloaded by zcashd during initial block download (IBD):

• Significant time and bandwidth is spent in issuing getheaders P2P requests. This results in noticeable bandwidth usage due to the large size of Zcash block headers.

  We now eliminate redundant requests in cases where we already know the last header in the message. This optimization is enabled by default, but can be disabled by setting the config option -nooptimize-getheaders.

• Transactions in the mempool are no longer downloaded during IBD (zcashd will only request block data).

Reduce upload traffic

A major part of the outbound traffic is caused by serving historic blocks to other nodes in initial block download state.

It is now possible to reduce the total upload traffic via the -maxuploadtarget parameter. This is not a hard limit but a threshold to minimize the outbound traffic. When the limit is about to be reached, the uploaded data is cut by not serving historic blocks (blocks older than one week). Moreover, any SPV peer is disconnected when they request a filtered block.

This option can be specified in MiB per day and is turned off by default (-maxuploadtarget=0). The recommended minimum is 1152 * MAX_BLOCK_SIZE (currently 2304MB) per day.

Whitelisted peers will never be disconnected, although their traffic counts for calculating the target.

A more detailed documentation about keeping traffic low can be found in /doc/reduce-traffic.md.

libzcashconsensus replaced by libzcash_script

The libzcashconsensus library inherited from upstream has been unusable since the Overwinter network upgrade in 2018. We made changes to signature digests similar to those made in Bitcoin's SegWit, which required additional per-input data that could not be added to the existing APIs without breaking backwards compatibility.

Additionally, it has become increasingly inaccurately named; it only covers (Zcash's subset of) the Bitcoin scripting system, and not the myriad of other consensus changes: in particular, Zcash's shielded pools.

We have now renamed the library to libzcash_script, and reworked it to instead focus on transparent script verification:

• The script verification APIs are altered to take consensusBranchId and amount fields.
• New precomputing APIs have been added that enable multiple transparent inputs on a single transaction to be verified more efficiently.
• Equihash has been removed from the compiled library. The canonical Equihash validator is the equihash Rust crate since v3.1.0.

The C++ library can be built by compiling zcashd with the environment variable CONFIGURE_FLAGS=--with-libs. It is also wrapped as the zcash_script Rust crate (maintained by the Zcash Foundation for use in zebrad).

Other P2P Changes

The list of banned peers is now stored on disk rather than in memory. Restarting zcashd will no longer clear out the list of banned peers; instead the clearbanned RPC method can be used to manually clear the list. The setban RPC method can also be used to manually ban or unban a peer.

Build system updates

• We now build with Clang 11 and Rust 1.49.
• We have downgraded Boost to 1.74 to mitigate statx-related breakage in some container environments.

Changelog

Alex Wied (3): Add support for FreeBSD 12 Set rust_target for all FreeBSD versions Use parentheses for defined in windows-unused-variables.diff

Alfredo Garcia (3): split wallet.py tests hide password in -stdin walletpassphrase command Apply suggestions from code review

Bernhard M. Wiedemann (1): Make tests pass after 2020

BtcDrak (1): Remove bad chain alert partition check

Carl Dong (13): build: Add variable printing target to Makefiles depends: Propagate well-known vars into depends depends: boost: Specify toolset to bootstrap.sh depends: boost: Split target-os from toolset depends: boost: Use clang toolset if clang in CXX depends: Propagate only specific CLI variables to sub-makes depends: boost: Refer to version in URL depends: boost: Split into non-/native packages depends: boost: Disable all compression depends: boost: Cleanup architecture/address-model depends: boost: Cleanup toolset selection depends: boost: Remove unnecessary archiver depends: boost: Specify cflags+compileflags

Casey Rodarmor (3): Make limited map actually respect max size Disallow unlimited limited maps Add limitedmap test

Cory Fields (6): depends: fix boost mac cross build with clang 9+ build: add missing leveldb defines net: make Ban/Unban/ClearBan functionality consistent net: No need to export DumpBanlist net: move CBanDB and CAddrDB out of net.h/cpp net: Drop CNodeRef for AttemptToEvictConnection

Daira Hopwood (2): qa/zcash/updatecheck.py: remove dead code; print instructions to run cargo outdated and cargo update. Ensure that CONFIGURE_FLAGS=--enable-debug correctly uses -O0 for dependencies and main build.

Daniel Kraft (1): doc: add comment explaining initial header request

Dimitris Apostolou (1): Discord invite instead of direct link

Ethan Heilman (1): Fix de-serialization bug where AddrMan is corrupted after exception * CAddrDB modified so that when de-serialization code throws an exception Addrman is reset to a clean state * CAddrDB modified to make unit tests possible * Regression test created to ensure bug is fixed * StartNode modifed to clear adrman if CAddrDB::Read returns an error code.

Gregory Maxwell (2): Return early in IsBanned. Disconnect on mempool requests from peers when over the upload limit.

Igor Cota (1): Define TARGET_OS when host is android

Jack Grigg (46): Add JSDescriptionInfo for constructing JSDescriptions Remove JSDescription::h_sig prevector: Terminate without logging on failed allocation Remove init_and_check_sodium from crypto/common.h Store inputs and outputs by reference in JSDescriptionInfo depends: Update Rust to 1.49.0 rust: Use renamed broken_intra_doc_links lint depends: cargo update depends: Move to Clang 11 depends: Fix Boost warnings under Clang 11 depends: Allow per-host package download paths depends: Ensure the native_clang download path is for the builder Revert "Update boost to 1.75, postpone other updates." qa: Postpone Boost and native_b2 updates QA: Remove unused update postponements QA: Postpone BDB update again depends: ZeroMQ 4.3.4 depends: Postpone updates that require adding CMake cargo update Squashed 'src/univalue/' changes from 9ef5b78c1..98fadc090 Remove crypto/equihash from libzcashconsensus Add amount and consensus branch ID to zcashconsensus_verify_script Rename src/script/zcashconsensus.* -> src/script/zcash_script.* Rename zcashconsensus_* -> zcash_script_* in APIs Rename libzcashconsensus.la -> libzcash_script.la Set up an mdbook in which we can document zcashd's architecture design Actions: Add a workflow to deploy the zcashd book Show README as root of zcashd book Link to zips.z.cash for protocol spec test: Convert Bech32 test vectors into known-answer test vectors zcash_script: Add API to verify scripts with precomputed tx data test: Migrate maxuploadtarget.py to Python 3 Pass current PoWTargetSpacing() into CNode::OutboundTargetReached() init: Pass post-Blossom spacing into CNode::SetMaxOutboundTarget() Fix some typos zcash_script: Clarify return values in docs Rename responsible_disclosure.md to SECURITY.md Add IBD download traffic reduction to release notes Fill out the rest of the 4.3.0 release notes make-release.py: Versioning changes for 4.3.0-rc1. make-release.py: Updated manpages for 4.3.0-rc1. make-release.py: Updated release notes and changelog for 4.3.0-rc1. cargo update rust: Pin funty =1.1.0 make-release.py: Versioning changes for 4.3.0. make-release.py: Updated manpages for 4.3.0.

Jeremy Rubin (1): Minimal fix to slow prevector tests as stopgap measure

Jonas Schnelli (14): banlist.dat: store banlist on disk CAddrDB/CBanDB: change filesize variables from int to uint64_t use CBanEntry as object container for banned nodes Adding CSubNet constructor over a single CNetAddr [Qt] add ui signal for banlist changes [Qt] banlist, UI optimizing and better signal handling net: use CIDR notation in CSubNet::ToString() [QA] fix netbase tests because of new CSubNet::ToString() output Introduce -maxuploadtarget [doc] add documentation how to reduce traffic don't enforce maxuploadtargets disconnect for whitelisted peers [docs] rename reducetraffic.md to reduce-traffic.md add documentation for exluding whitelistes peer from maxuploadtarget add (max)uploadtarget infos to getnettotals RPC help

Josh Lehan (1): Re-organize -maxconnections option handling

Karel Bilek (1): scripted-diff: Use UniValue.pushKV instead of push_back(Pair())

Kaz Wesley (4): fix race that could fail to persist a ban prevector: destroy elements only via erase() test prevector::swap prevector::swap: fix (unreached) data corruption

Kris Nuttycombe (4): Skip "tx" messages during initial block download. Fix pyflakes complaints Whitespace-only fix in chainparams.cpp Update the maxuploadtarget.py tests to accommodate zcash.

Larry Ruane (1): #4624 improve IBD sync by eliminating getheaders requests

Marco Falke (3): [net] Cleanup maxuploadtarget [doc] Add -maxuploadtarget release notes [walletdb] Add missing LOCK() in Recover() for dummyWallet

Marius Kjærstad (3): Update _COPYRIGHT_YEAR in configure.ac to 2021 Update COPYRIGHT_YEAR in clientversion.h to 2021 Update of copyright year to 2021

Marshall Gaucher (1): add libxml2

Matt Corallo (6): Default to defining endian-conversion DECLs in compat w/o config Make fDisconnect an std::atomic Make fImporting an std::atomic Fix AddrMan locking Remove double brackets in addrman Fix unlocked access to vNodes.size()

Patrick Strateman (1): Avoid recalculating vchKeyedNetGroup in eviction logic.

Peter Bushnell (1): depends: Consistent use of package variable

Peter Todd (1): Remove LOCK(cs_main) from decodescript

Philip Kaufmann (4): banlist: update set dirty to be more fine grained banlist: better handling of banlist in StartNode() banlist: add more banlist infos to log / add GUI signal banlist (bugfix): allow CNode::SweepBanned() to run on interval

Pieter Wuille (11): Add SipHash-2-4 primitives to hash Use SipHash-2-4 for CCoinsCache index Switch CTxMempool::mapTx to use a hash index for txids Use SipHash-2-4 for address relay selection Add extra message to avoid a long 'Loading banlist' Support SipHash with arbitrary byte writes Use 64-bit SipHash of netgroups in eviction Use C++11 thread-safe static initializers Add ChaCha20 Switch FastRandomContext to ChaCha20 Add a FastRandomContext::randrange and use it

Suhas Daftuar (1): Add RPC test for -maxuploadtarget

Taylor Hornby (2): Move the github API token out of updatecheck.py into an untracked file. Document the required .updatecheck-token file in the release docs

Wladimir J. van der Laan (6): build: Updates for OpenBSD net: Fix CIDR notation in ToString() test: Add more test vectors for siphash timedata: Prevent warning overkill Always allow getheaders from whitelisted peers rpc: remove cs_main lock from createrawtransaction

fanquake (2): [build] Add NETBSD leveldb target to configure.ac [doc] Improve lanaguge in reducetraffic.md

kirkalx (1): peers.dat, banlist.dat recreated when missing

Marshall Gaucher (1): add zstd package

randy-waterhouse (1): Re-instate TARGET_OS=linux in configure.ac. Removed by 351abf9e035.

Jack Grigg (1): Update URL for Zcash Foundation security policy

Ying Tong Lai (2): Cargo update Postpone dependencies

tulip (1): Move time data log print to 'net' category to reduce log noise

Benjamin Winston (1): Added foundation to responsible_disclosure.md