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2020-06-18[net] split PushInventory()John Newbery
PushInventory() is currently called with a CInv object, which can be a MSG_TX or MSG_BLOCK. PushInventory() only uses the type to determine whether to add the hash to setInventoryTxToSend or vInventoryBlockToSend. Since the caller always knows what type of inventory they're pushing, the CInv is wastefully constructed and thrown away, and tx/block relay is being split out, we split the function into PushTxInventory() and PushBlockInventory().
2020-06-09scripted-diff: replace MAX_BLOCKS_ONLY_CONNECTIONS with ā†µglowang
MAX_BLOCK_RELAY_ONLY_CONNECTIONS -BEGIN VERIFY SCRIPT- sed -i 's/\<MAX_BLOCKS_ONLY_CONNECTIONS\>/MAX_BLOCK_RELAY_ONLY_CONNECTIONS/g' src/init.cpp sed -i 's/\<MAX_BLOCKS_ONLY_CONNECTIONS\>/MAX_BLOCK_RELAY_ONLY_CONNECTIONS/g' src/net.h -END VERIFY SCRIPT-
2020-05-27Merge #16127: More thread safety annotation coverageMarcoFalke
5478d6c099e76fe070703cc5383cba7b91468b0f logging: thread safety annotations (Anthony Towns) e685ca19928eec4e687c66f5edfcfff085a42c27 util/system.cpp: add thread safety annotations for dir_locks (Anthony Towns) a7887899480db72328784009181d93904e6d479d test/checkqueue_tests: thread safety annotations (Anthony Towns) 479c5846f7477625ec275fbb8a076c7ef157172b rpc/blockchain.cpp: thread safety annotations for latestblock (Anthony Towns) 8b5af3d4c1270267ad85e78f661bf8fab06f3aad net: fMsgProcWake use LOCK instead of lock_guard (Anthony Towns) de7c5f41aba860751ef7824245e6d9d5088a1200 wallet/wallet.h: Remove mutexScanning which was only protecting a single atomic bool (Anthony Towns) c3cf2f55013c4ea1c1ef4a878fc7ff8e92f2c42d rpc/blockchain.cpp: Remove g_utxosetscan mutex that is only protecting a single atomic variable (Anthony Towns) Pull request description: In a few cases we need to use `std::mutex` rather than the sync.h primitives. But `std::lock_guard<std::mutex>` doesn't include the clang thread safety annotations unless you also use clang's C library, which means you can't indicate when variables should be guarded by `std::mutex` mutexes. This adds an annotated version of `std::lock_guard<std::mutex>` to threadsafety.h to fix that, and modifies places where `std::mutex` is used to take advantage of the annotations. It's based on top of #16112, and turns the thread safety comments included there into annotations. It also changes the RAII classes in wallet/wallet.h and rpc/blockchain.cpp to just use the atomic<bool> flag for synchronisation rather than having a mutex that doesn't actually guard anything as well. ACKs for top commit: MarcoFalke: ACK 5478d6c099e76fe070703cc5383cba7b91468b0f šŸ—¾ hebasto: re-ACK 5478d6c099e76fe070703cc5383cba7b91468b0f, only renamed s/`MutexGuard`/`LockGuard`/, and dropped the commit "test/util_threadnames_tests: add thread safety annotations" since the [previous](https://github.com/bitcoin/bitcoin/pull/16127#pullrequestreview-414184113) review. ryanofsky: Code review ACK 5478d6c099e76fe070703cc5383cba7b91468b0f. Thanks for taking suggestions! Only changes since last review are dropping thread rename test commit d53072ec730d8eec5a5b72f7e65a54b141e62b19 and renaming mutex guard to lock guard Tree-SHA512: 7b00d31f6f2b5a222ec69431eb810a74abf0542db3a65d1bbad54e354c40df2857ec89c00b4a5e466c81ba223267ca95f3f98d5fbc1a1d052a2c3a7d2209790a
2020-05-19net: fMsgProcWake use LOCK instead of lock_guardAnthony Towns
2020-05-12p2p: add MAX_FEELER_CONNECTIONS constanttryphe
2020-05-11refactor: s/command/msg_type/ in CNetMsgMaker and CSerializedNetMsgSebastian Falbesoner
2020-05-05Make ThreadSafe{MessageBox|Question} bilingualHennadii Stepanov
2020-04-23[net processing] Move net processing consts to net_processing.cppJohn Newbery
2020-04-20Merge #18544: net: limit BIP37 filter lifespan (active between ā†µMarcoFalke
'filterload'..'filterclear') a9ecbdfcaa15499644d16e9c8ad2c63dfc45b37b test: add more inactive filter tests to p2p_filter.py (Sebastian Falbesoner) 5eae034996b340c19cebab9efb6c89d20fe051ef net: limit BIP37 filter lifespan (active between 'filterload' and 'filterclear') (Sebastian Falbesoner) Pull request description: This PR fixes https://github.com/bitcoin/bitcoin/issues/18483. On the master branch, there is currently _always_ a BIP37 filter set for every peer: if not a specific filter is set through a `filterload` message, a default match-everything filter is instanciated and pointed to via the `CBloomFilter` default constructor; that happens both initially, when the containing structure `TxRelay` is constructed: https://github.com/bitcoin/bitcoin/blob/c0b389b33516fb3eaaad7c30bd11dba768882a7e/src/net.h#L812 and after a loaded filter is removed again through a `filterclear` message: https://github.com/bitcoin/bitcoin/blob/c0b389b33516fb3eaaad7c30bd11dba768882a7e/src/net_processing.cpp#L3201 The behaviour was introduced by commit https://github.com/bitcoin/bitcoin/commit/37c6389c5a0ca63ae3573440ecdfe95d28ad8f07 (an intentional covert fix for [CVE-2013-5700](https://github.com/bitcoin/bitcoin/pull/18515), according to gmaxwell). This default match-everything filter leads to some unintended side-effects: 1. `getdata` request for filtered blocks (i.e. type `MSG_FILTERED_BLOCK`) are always responded to with `merkleblock`s, even if no filter was set by the peer, see issue #18483 (strictly speaking, this is a violation of BIP37) https://github.com/bitcoin/bitcoin/blob/c0b389b33516fb3eaaad7c30bd11dba768882a7e/src/net_processing.cpp#L1504-L1507 2. if a peer sends a `filteradd` message without having loaded a filter via `filterload` before, the intended increasing of the banscore never happens (triggered if `bad` is set to true, a few lines below) https://github.com/bitcoin/bitcoin/blob/c0b389b33516fb3eaaad7c30bd11dba768882a7e/src/net_processing.cpp#L3182-L3186 This PR basically activates the `else`-branch code paths for all checks of `pfilter` again (on the master branch, they are dead code) by limiting the pointer's lifespan: instead of always having a filter set, the `pfilter` is only pointing to a `CBloomFilter`-instance after receiving a `filterload` message and the instance is destroyed again (and the pointer nullified) after receiving a `filterclear` message. Here is a before/after comparison in behaviour: | code part / scenario | master branch | PR branch | | --------------------------------------------- | ---------------------------------- | ---------------------------------------------------- | | `getdata` processing for `MSG_FILTERED_BLOCK` | always responds with `merkleblock` | only responds if filter was set via `filterload` | | `filteradd` processing, no filter was loaded | nothing | peer's banscore increases by 100 (i.e. disconnect) | On the other code parts where `pfilter` is checked there is no change in the logic behaviour (except that `CBloomFilter::IsRelevantAndUpdate()` is unnecessarily called and immediately returned in the master branch). Note that the default constructor of `CBloomFilter` is only used for deserializing the received `filterload` message and nowhere else. The PR also contains a functional test checking that sending `getdata` for filtered blocks is ignored by the node if no bloom filter is set. ACKs for top commit: MarcoFalke: re-ACK a9ecbdfcaa, only change is in test code šŸ•™ Tree-SHA512: 1a656a6d74ccaf628e7fdca063ba63fbab2089e0b6d0a11be9bbd387c2ee6d3230706ff8ffc1a55711481df3d4547137dd7c9d9184d89eaa43ade4927792d0b6
2020-04-10Merge #18454: net: Make addr relay mockable, add testMarcoFalke
fa1da3d4bfc0511a89f5b19d5a4d89e55ff7ccde test: Add basic addr relay test (MarcoFalke) fa1793c1c44a3f75a09f9c636467b8274c541bdd net: Pass connman const when relaying address (MarcoFalke) fa47a0b003f53708b6d5df1ed4e7f8a7c68aa3ac net: Make addr relay mockable (MarcoFalke) Pull request description: As usual: * Switch to std::chrono time to be type-safe and mockable * Add basic test that relies on mocktime to add code coverage ACKs for top commit: naumenkogs: utACK fa1da3d promag: ACK fa1da3d4bfc0511a89f5b19d5a4d89e55ff7ccde (fabe56e44b6f683e24e37246a7a8851190947cb3 before https://github.com/bitcoin/bitcoin/pull/18454#issuecomment-607866453), fa5bf23d527a450e72c2bf13d013e5393b664ca3 was dropped since last review. Tree-SHA512: 0552bf8fcbe375baa3cab62acd8c23b2994efa47daff818ad1116d0ffaa0b9e520dc1bca2bbc68369b25584e85e54861fe6fd0968de4f503b95439c099df9bd7
2020-04-09net: limit BIP37 filter lifespan (active between 'filterload' and 'filterclear')Sebastian Falbesoner
Previously, a default match-everything bloom filter was set for every peer, i.e. even before receiving a 'filterload' message and after receiving a 'filterclear' message code branches checking for the existence of the filter by testing the pointer "pfilter" were _always_ executed.
2020-04-09Merge #18521: fuzz: Add process_messages harnessMarcoFalke
fa6a00843447d53a5708ea3a629b9150cfe58be2 fuzz: Add process_messages harness (MarcoFalke) Pull request description: ACKs for top commit: practicalswift: Tested ACK fa6a00843447d53a5708ea3a629b9150cfe58be2 Tree-SHA512: 2d8788308c7f45c97ca003378f58a9d51f51265958557a65e5e505b1666b4cb928f0d010622870175090a0ad25e2d10b41f26f4eef14b6ff334a024baa250f8c
2020-04-05fuzz: Add process_messages harnessMarcoFalke
2020-03-29net: Add missing cs_vNodes lockMarcoFalke
2020-03-27net: Make addr relay mockableMarcoFalke
2020-03-04refactor: Convert ping wait time from double to int64_tBen Woosley
2020-03-04refactor: Convert min ping time from double to int64_tBen Woosley
2020-03-04refactor: Convert ping time from double to int64_tBen Woosley
2020-02-28Merge #16562: Refactor message transport packagingMarcoFalke
16d6113f4faa901e248adb693d4768a9e5019a16 Refactor message transport packaging (Jonas Schnelli) Pull request description: This PR factors out transport packaging logic from `CConnman::PushMessage()`. It's similar to #16202 (where we refactor deserialization). This allows implementing a new message transport protocol like BIP324. ACKs for top commit: dongcarl: ACK 16d6113f4faa901e248adb693d4768a9e5019a16 FWIW ariard: Code review ACK 16d6113 elichai: semiACK 16d6113f4faa901e248adb693d4768a9e5019a16 ran functional+unit tests. MarcoFalke: ACK 16d6113f4faa901e248adb693d4768a9e5019a16 šŸ™Ž Tree-SHA512: 8c2f8ab9f52e9b94327973ae15019a08109d5d9f9247492703a842827c5b5d634fc0411759e0bb316d824c586614b0220c2006410851933613bc143e58f7e6c1
2020-01-31Mark asmap const in statistics codePieter Wuille
2020-01-31Avoid asmap copies in initializationPieter Wuille
2020-01-29Merge #16702: p2p: supplying and using asmap to improve IP bucketing in addrmanWladimir J. van der Laan
3c1bc40205a3fcab606e70b0e3c13d68b2860e34 Add extra logging of asmap use and bucketing (Gleb Naumenko) e4658aa8eaf1629dd5af8cf7b9717a8e72028251 Return mapped AS in RPC call getpeerinfo (Gleb Naumenko) ec45646de9e62b3d42c85716bfeb06d8f2b507dc Integrate ASN bucketing in Addrman and add tests (Gleb Naumenko) 8feb4e4b667361bf23344149c01594abebd56fdb Add asmap utility which queries a mapping (Gleb Naumenko) Pull request description: This PR attempts to solve the problem explained in #16599. A particular attack which encouraged us to work on this issue is explained here [[Erebus Attack against Bitcoin Peer-to-Peer Network](https://erebus-attack.comp.nus.edu.sg/)] (by @muoitranduc) Instead of relying on /16 prefix to diversify the connections every node creates, we would instead rely on the (ip -> ASN) mapping, if this mapping is provided. A .map file can be created by every user independently based on a router dump, or provided along with the Bitcoin release. Currently we use the python scripts written by @sipa to create a .map file, which is no larger than 2MB (awesome!). Here I suggest adding a field to peers.dat which would represent a hash of asmap file used while serializing addrman (or 0 for /16 prefix legacy approach). In this case, every time the file is updated (or grouping method changed), all buckets will be re-computed. I believe that alternative selective re-bucketing for only updated ranges would require substantial changes. TODO: - ~~more unit tests~~ - ~~find a way to test the code without including >1 MB mapping file in the repo.~~ - find a way to check that mapping file is not corrupted (checksum?) - comments and separate tests for asmap.cpp - make python code for .map generation public - figure out asmap distribution (?) ~Interesting corner case: Iā€™m using std::hash to compute a fingerprint of asmap, and std::hash returns size_t. I guess if a user updates the OS to 64-bit, then the hash of asap will change? Does it even matter?~ ACKs for top commit: laanwj: re-ACK 3c1bc40205a3fcab606e70b0e3c13d68b2860e34 jamesob: ACK 3c1bc40205a3fcab606e70b0e3c13d68b2860e34 ([`jamesob/ackr/16702.3.naumenkogs.p2p_supplying_and_using`](https://github.com/jamesob/bitcoin/tree/ackr/16702.3.naumenkogs.p2p_supplying_and_using)) jonatack: ACK 3c1bc40205a3fcab606e70b0e3c13d68b2860e34 Tree-SHA512: e2dc6171188d5cdc2ab2c022fa49ed73a14a0acb8ae4c5ffa970172a0365942a249ad3d57e5fb134bc156a3492662c983f74bd21e78d316629dcadf71576800c
2020-01-23Return mapped AS in RPC call getpeerinfoGleb Naumenko
If ASN bucketing is used, return a corresponding AS used in bucketing for a given peer.
2020-01-22Refactor message transport packagingJonas Schnelli
2020-01-15scripted-diff: Bump copyright of files changed in 2020MarcoFalke
-BEGIN VERIFY SCRIPT- ./contrib/devtools/copyright_header.py update ./ -END VERIFY SCRIPT-
2020-01-15scripted-diff: Replace CCriticalSection with RecursiveMutexMarcoFalke
-BEGIN VERIFY SCRIPT- # Delete outdated alias for RecursiveMutex sed -i -e '/CCriticalSection/d' ./src/sync.h # Replace use of outdated alias with RecursiveMutex sed -i -e 's/CCriticalSection/RecursiveMutex/g' $(git grep -l CCriticalSection) -END VERIFY SCRIPT-
2020-01-10gui: Set CConnman byte counters earlier to avoid uninitialized readsRussell Yanofsky
Initialize CConnman byte counters during construction, so GetTotalBytesRecv() and GetTotalBytesSent() methods don't return garbage before Start() is called. Change shouldn't have any effect outside of the GUI. It just fixes a race condition during a qt test that was observed on travis: https://travis-ci.org/bitcoin/bitcoin/jobs/634989685
2019-12-25Integrate ASN bucketing in Addrman and add testsGleb Naumenko
Instead of using /16 netgroups to bucket nodes in Addrman for connection diversification, ASN, which better represents an actor in terms of network-layer infrastructure, is used. For testing, asmap.raw is used. It represents a minimal asmap needed for testing purposes.
2019-11-05Merge #17243: p2p: add PoissonNextSend method that returns mockable timeMarcoFalke
1a8f0d5a74d5cc0000456932babf35301f5c1686 [tools] update nNextInvSend to use mockable time (Amiti Uttarwar) 4de630354fc6808b9b13b9e82da1a82f2f50f26a [tools] add PoissonNextSend method that returns mockable time (Amiti Uttarwar) Pull request description: Introduce a Poisson helper method that wraps the existing method to return `std::chrono::duration` type, which is mockable. Needed for https://github.com/bitcoin/bitcoin/pull/16698. ACKs for top commit: ajtowns: ACK 1a8f0d5a74d5cc0000456932babf35301f5c1686 MarcoFalke: re-ACK 1a8f0d5a74d5cc0000456932babf35301f5c1686 naumenkogs: ACK 1a8f0d5, and let's merge it and come back to it later. Tree-SHA512: 7e2325d7c55fc0b4357cb86b83e0c218ba269f678c1786342d8bc380bfd9696373bc24ff124b9ff17a6e761c62b2b44ff5247c3911e2afdc7cc5c20417e8290b
2019-11-05[tools] update nNextInvSend to use mockable timeAmiti Uttarwar
2019-11-05[tools] add PoissonNextSend method that returns mockable timeAmiti Uttarwar
2019-11-04Merge #17164: p2p: Avoid allocating memory for addrKnown where we don't need itMarcoFalke
b6d2183858975abc961207c125c15791e531edcc Minor refactoring to remove implied m_addr_relay_peer. (User) a552e8477c5bcd22a5457f4f73a2fd6db8acd2c2 added asserts to check m_addr_known when it's used (User) 090b75c14be6b9ba2efe38a17d141c6e6af575cb p2p: Avoid allocating memory for addrKnown where we don't need it (User) Pull request description: We should allocate memory for addrKnown filter only for those peers which are expected to participate in address relay. Currently, we do it for all peers (including SPV and block-relay-only), which results in extra RAM where it's not needed. Upd: In future, we would still allow SPVs to ask for addrs, so allocation still will be done by default. However, they will be able to opt-out via [this proposal](https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2019-October/017428.html) and then we could save some more memory. This PR still saves memory for block-relay-only peers immediately after merging. Top commit has no ACKs. Tree-SHA512: e84d93b2615556d466f5ca0e543580fde763911a3bfea3127c493ddfaba8f05c8605cb94ff795d165af542b594400995a2c51338185c298581408687e7812463
2019-10-31Minor refactoring to remove implied m_addr_relay_peer.User
Co-authored-by: MarcoFalke <falke.marco@gmail.com>
2019-10-28scripted-diff: Remove g_connman, g_banman globalsRussell Yanofsky
-BEGIN VERIFY SCRIPT- sed -i 's:#include <interfaces/chain.h>:#include <banman.h>\n#include <interfaces/chain.h>\n#include <net.h>\n#include <net_processing.h>:' src/node/context.cpp sed -i 's/namespace interfaces {/class BanMan;\nclass CConnman;\nclass PeerLogicValidation;\n&/' src/node/context.h sed -i 's/std::unique_ptr<interfaces::Chain> chain/std::unique_ptr<CConnman> connman;\n std::unique_ptr<PeerLogicValidation> peer_logic;\n std::unique_ptr<BanMan> banman;\n &/' src/node/context.h sed -i '/std::unique_ptr<[^>]\+> \(g_connman\|g_banman\|peerLogic\);/d' src/banman.h src/net.h src/init.cpp sed -i 's/g_connman/m_context.connman/g' src/interfaces/node.cpp sed -i 's/g_banman/m_context.banman/g' src/interfaces/node.cpp sed -i 's/g_connman/m_node.connman/g' src/interfaces/chain.cpp src/test/setup_common.cpp sed -i 's/g_banman/m_node.banman/g' src/test/setup_common.cpp sed -i 's/g_connman/node.connman/g' src/init.cpp src/node/transaction.cpp sed -i 's/g_banman/node.banman/g' src/init.cpp sed -i 's/peerLogic/node.peer_logic/g' src/init.cpp sed -i 's/g_connman/g_rpc_node->connman/g' src/rpc/mining.cpp src/rpc/net.cpp src/rpc/rawtransaction.cpp sed -i 's/g_banman/g_rpc_node->banman/g' src/rpc/net.cpp sed -i 's/std::shared_ptr<CWallet> wallet =/node.context()->connman = std::move(test.m_node.connman);\n &/' src/qt/test/wallettests.cpp -END VERIFY SCRIPT-
2019-10-25added asserts to check m_addr_known when it's usedUser
2019-10-23Add override/final modifiers to V1TransportDeserializerPieter Wuille
2019-10-23Make resetting implicit in TransportDeserializer::Read()Pieter Wuille
2019-10-23Remove oversized message detection from log and interfacePieter Wuille
2019-10-22Force CNetMessage::m_recv to use std::moveJonas Schnelli
2019-10-18Use adapter pattern for the network deserializerJonas Schnelli
2019-10-18Remove transport protocol knowhow from CNetMessage / net processingJonas Schnelli
2019-10-18Refactor: split network transport deserializing from message containerJonas Schnelli
2019-10-16p2p: Avoid allocating memory for addrKnown where we don't need itUser
2019-09-23txmempool: Make entry time type-safe (std::chrono)MarcoFalke
2019-09-11doc: add comments clarifying how local services are advertisedJames O'Beirne
Recent questions have come up regarding dynamic service registration (see https://github.com/bitcoin/bitcoin/pull/16442#discussion_r308702676 and the assumeutxo project, which needs to dynamically flip NODE_NETWORK). While investigating how dynamic service registration might work, I was confused about how we convey local services to peers. This adds some documentation that hopefully clarifies this process.
2019-09-07Merge #15759: p2p: Add 2 outbound block-relay-only connectionsfanquake
0ba08020c9791f7caf5986ad6490c16a2b66cd83 Disconnect peers violating blocks-only mode (Suhas Daftuar) 937eba91e1550bc3038dc541c236ac83e0a0e6d5 doc: improve comments relating to block-relay-only peers (Suhas Daftuar) 430f489027f15c1e4948ea4378954df24e3fee88 Don't relay addr messages to block-relay-only peers (Suhas Daftuar) 3a5e885306ea954d7eccdc11502e91a51dab8ec6 Add 2 outbound block-relay-only connections (Suhas Daftuar) b83f51a4bbe29bf130a2b0c0e85e5bffea107f75 Add comment explaining intended use of m_tx_relay (Suhas Daftuar) e75c39cd425f8c4e5b6bbb2beecb9c80034fefe1 Check that tx_relay is initialized before access (Suhas Daftuar) c4aa2ba82211ea5988ed7fe21e1b08bc3367e6d4 [refactor] Change tx_relay structure to be unique_ptr (Suhas Daftuar) 4de0dbac9b286c42a9b10132b7c2d76712f1a319 [refactor] Move tx relay state to separate structure (Suhas Daftuar) 26a93bce29fd813e1402b013f402869c25b656d1 Remove unused variable (Suhas Daftuar) Pull request description: Transaction relay is optimized for a combination of redundancy/robustness as well as bandwidth minimization -- as a result transaction relay leaks information that adversaries can use to infer the network topology. Network topology is better kept private for (at least) two reasons: (a) Knowledge of the network graph can make it easier to find the source IP of a given transaction. (b) Knowledge of the network graph could be used to split a target node or nodes from the honest network (eg by knowing which peers to attack in order to achieve a network split). We can eliminate the risks of (b) by separating block relay from transaction relay; inferring network connectivity from the relay of blocks/block headers is much more expensive for an adversary. After this commit, bitcoind will make 2 additional outbound connections that are only used for block relay. (In the future, we might consider rotating our transaction-relay peers to help limit the effects of (a).) ACKs for top commit: sipa: ACK 0ba08020c9791f7caf5986ad6490c16a2b66cd83 ajtowns: ACK 0ba08020c9791f7caf5986ad6490c16a2b66cd83 -- code review, ran tests. ran it on mainnet for a couple of days with MAX_BLOCKS_ONLY_CONNECTIONS upped from 2 to 16 and didn't observe any unexpected behaviour: it disconnected a couple of peers that tried sending inv's, and it successfully did compact block relay with some block relay peers. TheBlueMatt: re-utACK 0ba08020c9791f7caf5986ad6490c16a2b66cd83. Pointed out that stats.fRelayTxes was sometimes uninitialized for blocksonly peers (though its not a big deal and only effects RPC), which has since been fixed here. Otherwise changes are pretty trivial so looks good. jnewbery: utACK 0ba08020c9791f7caf5986ad6490c16a2b66cd83 jamesob: ACK https://github.com/bitcoin/bitcoin/commit/0ba08020c9791f7caf5986ad6490c16a2b66cd83 Tree-SHA512: 4c3629434472c7dd4125253417b1be41967a508c3cfec8af5a34cad685464fbebbb6558f0f8f5c0d4463e3ffa4fa3aabd58247692cb9ab8395f4993078b9bcdf
2019-09-04Don't relay addr messages to block-relay-only peersSuhas Daftuar
We don't want relay of addr messages to leak information about these network links.
2019-09-04Add 2 outbound block-relay-only connectionsSuhas Daftuar
Transaction relay is primarily optimized for balancing redundancy/robustness with bandwidth minimization -- as a result transaction relay leaks information that adversaries can use to infer the network topology. Network topology is better kept private for (at least) two reasons: (a) Knowledge of the network graph can make it easier to find the source IP of a given transaction. (b) Knowledge of the network graph could be used to split a target node or nodes from the honest network (eg by knowing which peers to attack in order to achieve a network split). We can eliminate the risks of (b) by separating block relay from transaction relay; inferring network connectivity from the relay of blocks/block headers is much more expensive for an adversary. After this commit, bitcoind will make 2 additional outbound connections that are only used for block relay. (In the future, we might consider rotating our transaction-relay peers to help limit the effects of (a).)
2019-09-04Add comment explaining intended use of m_tx_relaySuhas Daftuar
2019-09-04Check that tx_relay is initialized before accessSuhas Daftuar
generated by cgit v1.2.3 (git 2.26.2) at 2025-03-16 16:59:17 +0000