Allow multiple connections from the same Peer ID

[lzhzh1]

if the value of settings_pack::allow_multiple_connections_per_ip is true, then skip the check for the same pid
Add a new option allow_multiple_connections_per_pid. When set to true, it skips the duplicate Peer ID check, thereby allowing multiple connections from the same peer.
The issue #8214

[arvidn]

if you want to allow multiple connections to the same peer via different IP addresses, I don't think this is the right solution. you would still want to avoid multiple connections to the same IP

[arvidn]

Maybe it's OK to accept multiple connections to the same peer as long as they use different address families. But you could also have multiple routes to the internet. But the common case is (most likely) that you don't want to have multiple connections to the same peer.

[lzhzh1]

Maybe it's OK to accept multiple connections to the same peer as long as they use different address families. But you could also have multiple routes to the internet. But the common case is (most likely) that you don't want to have multiple connections to the same peer.

Thank you so much for your comments! I've introduced a new option, allow_multiple_connections_per_pid, to toggle the duplicate Peer ID check, which ensures other functionalities remain unaffected.

Since I'm still a beginner, I haven't been able to create a proper standalone test file yet. However, I've manually verified the logic by compiling my forked libtorrent and a simply modified version of qBittorrent to control the value of allow_multiple_connections_per_pid. It seems to be working as expected. Thanks again!"

allow_multiple_connections_per_pid = true

allow_multiple_connections_per_pid = false
(The result of manually forcing Tixati to disconnect established connections and then retry the connection)

[lzhzh1]

My apologies for the initial misunderstanding regarding the test files, which led me to place allow_multiple_connections_per_pid alongside allow_multiple_connections_per_ip. I have now added a new dedicated test file libtorrent/simulation/test_allow_multiple_connections_per_pid.cpp for it. I would appreciate any further feedback or suggestions you may have. Thank you!

root@hello-world:~/libtorrent/simulation# b2 test_allow_multiple_connections_per_pid
CXXFLAGS =
LDFLAGS =
OS = LINUX
BOOST_ROOT =
OS = LINUX
warning: No toolsets are configured.
warning: Configuring default toolset "gcc".
warning: If the default is wrong, your build may not work correctly.
warning: Use the "toolset=xxxxx" option to override our guess.
warning: For more configuration options, please consult
warning: https://www.bfgroup.xyz/b2/manual/release/index.html#bbv2.overview.configuration
warning: non-free usage requirements <threading>multi ignored
warning: in main-target simulator at libsimulator/Jamfile:105
...patience...
...found 2238 targets...
...updating 22 targets...
gcc.compile.c++ bin/test_allow_multiple_connections_per_pid.test/gcc-14/debug/asserts-on/crypto-built-in/cxxstd-14-iso/export-extra-on/invariant-checks-full/picker-debugging-on/simulator-on/threading-multi/test_allow_multiple_connections_per_pid.o
gcc.compile.c++ bin/test_allow_multiple_connections_per_pid.test/gcc-14/debug/asserts-on/crypto-built-in/cxxstd-14-iso/export-extra-on/invariant-checks-full/picker-debugging-on/simulator-on/threading-multi/create_torrent.o
gcc.compile.c++ bin/test_allow_multiple_connections_per_pid.test/gcc-14/debug/asserts-on/crypto-built-in/cxxstd-14-iso/export-extra-on/invariant-checks-full/picker-debugging-on/simulator-on/threading-multi/disk_io.o
gcc.compile.c++ bin/test_allow_multiple_connections_per_pid.test/gcc-14/debug/asserts-on/crypto-built-in/cxxstd-14-iso/export-extra-on/invariant-checks-full/picker-debugging-on/simulator-on/threading-multi/setup_dht.o
gcc.compile.c++ bin/test_allow_multiple_connections_per_pid.test/gcc-14/debug/asserts-on/crypto-built-in/cxxstd-14-iso/export-extra-on/invariant-checks-full/picker-debugging-on/simulator-on/threading-multi/setup_swarm.o
gcc.compile.c++ bin/test_allow_multiple_connections_per_pid.test/gcc-14/debug/asserts-on/crypto-built-in/cxxstd-14-iso/export-extra-on/invariant-checks-full/picker-debugging-on/simulator-on/threading-multi/transfer_sim.o
gcc.compile.c++ bin/test_allow_multiple_connections_per_pid.test/gcc-14/debug/asserts-on/crypto-built-in/cxxstd-14-iso/export-extra-on/invariant-checks-full/picker-debugging-on/simulator-on/threading-multi/utils.o
gcc.link bin/test_allow_multiple_connections_per_pid.test/gcc-14/debug/asserts-on/crypto-built-in/cxxstd-14-iso/export-extra-on/invariant-checks-full/picker-debugging-on/simulator-on/threading-multi/test_allow_multiple_connections_per_pid
testing.capture-output bin/test_allow_multiple_connections_per_pid.test/gcc-14/debug/asserts-on/crypto-built-in/cxxstd-14-iso/export-extra-on/invariant-checks-full/picker-debugging-on/simulator-on/threading-multi/test_allow_multiple_connections_per_pid.run
**passed** bin/test_allow_multiple_connections_per_pid.test/gcc-14/debug/asserts-on/crypto-built-in/cxxstd-14-iso/export-extra-on/invariant-checks-full/picker-debugging-on/simulator-on/threading-multi/test_allow_multiple_connections_per_pid.test
...updated 22 targets...

[lzhzh1]

Thanks for your review! I removed the unnecessary code and merged the test code.

[milahu]

nitpick: this should be renamed

-allow_multiple_connections_per_pid
+allow_multiple_connections_per_peer_id

-simulation/test_allow_multiple_connections_per_pid.cpp
+simulation/test_allow_multiple_connections_per_peer_id.cpp

to make it consistent with the rest of the codebase

libtorrent/include/libtorrent/close_reason.hpp

Line 49 in cb6fe6b

duplicate_peer_id,

fixed in #8373

[Rootax]

Was this merged into 2.1 rc2 ?

[lzhzh1]

Was this merged into 2.1 rc2 ?

Yes!

[Rootax]

Was this merged into 2.1 rc2 ?

Yes!

Thx, I was not sure. it seems qbittorrent master doesn't expose de setting in the gui yet.