Two commit on top of #9919 (first adds the implementation, second adds a test). Make it possible to listen and connect to UNIX sockets for P2P. There are two main use cases for this:
Usage: specify :unix:<path> for bind, whitebind, connect, addnode.
Add functionality for RPC over UNIX sockets, on platforms that support
UNIX sockets. This is specified with `:unix:/path/to/socket` to
`-rpcbind` and `-rpcconnect`. By default the socket path is relative to the
data directory.
evhttp has no direct support for UNIX sockets thus
is not able to recognize UNIX peers. Add custom code in
HTTPRequest::GetPeer and evunix to recognize these connections
as coming from localhost.
The previous solution did not work on some libevent versions.
Make it possible to listen and connect to UNIX sockets for P2P.
There are two main use cases for this:
- Testing without possibility of port collisions
- TOR hidden service listening with less risk of privacy leaks by not
opening any internet ports
Usage: specify `:unix:<path>` for `bind`, `whitebind`, `connect`,
`addnode`.
336@@ -331,6 +337,8 @@ static bool HTTPBindAddresses(struct evhttp* http)
337 } else if (mapMultiArgs.count("-rpcbind")) { // Specific bind address
338 const std::vector<std::string>& vbind = mapMultiArgs.at("-rpcbind");
339 for (std::vector<std::string>::const_iterator i = vbind.begin(); i != vbind.end(); ++i) {
340+ if (boost::starts_with(*i, RPC_ADDR_PREFIX_UNIX)) // Skip UNIX sockets here
an easy way to replicate this without a new boost dep is:
0if (!i->rfind(RPC_ADD_PREFIX_UNIX, 0))
197@@ -195,8 +198,35 @@ UniValue CallRPC(const std::string& strMethod, const UniValue& params)
198 // Obtain event base
199 raii_event_base base = obtain_event_base();
200
201- // Synchronously look up hostname
202- raii_evhttp_connection evcon = obtain_evhttp_connection_base(base.get(), host, port);
203+ raii_evhttp_connection evcon;
204+ if (boost::starts_with(host, RPC_ADDR_PREFIX_UNIX)) {
205+#if defined(HAVE_SOCKADDR_UN) && defined(LIBEVENT_EXPERIMENTAL)
Might be better to have the ifdef define two different functions HandleUnixSocket.
I’m always nervous with compiler directives inside functions, unless the code switched is ~1 line. Large ifdefs are in a couple places in this PR.
546@@ -505,6 +547,12 @@ void StopHTTPServer()
547 event_base_free(eventBase);
548 eventBase = 0;
549 }
550+#ifdef HAVE_SOCKADDR_UN
551+ //! Clean up UNIX sockets on shutdown
552+ for (const auto& path: cleanupUNIXSockets) {
slight preference for something with ownership guarantees of
0std::vector<std::unique_ptr<void>> cleanupUNIXSockets;
1// must be non null value
2cleanupUNIXSockets.emplace_back(1, [=](void*) { evunix_remove_socket(path); });
3cleanupUNIXSockets.clear();
so that sockets aren’t double removed.
Maybe wrap the evunix stuff in a class and just keep a vector of those around?
666@@ -619,6 +667,12 @@ CService HTTPRequest::GetPeer()
667 const char* address = "";
668 uint16_t port = 0;
669 evhttp_connection_get_peer(con, (char**)&address, &port);
670+ if (!strcmp(address, "localhost")) {
671+ /* Special: will get here for UNIX sockets. As we have no way to indicate that,
recommend comment language (took me a minute to understand your comment because of ambiguity on here and that):
We will get an address of localhost either via a unix socket or via a localhost peer. There is no sane way to return an address for a socket, so we always return localhost’s IPv6.
2108+ LogPrintf("P2P bound to %s\n", path.string());
2109+
2110+ // Listen for incoming connections
2111+ if (listen(hListenSocket, SOMAXCONN) == SOCKET_ERROR)
2112+ {
2113+ strError = strprintf(_("Error: Listening for incoming connections failed (listen returned error %s)"), NetworkErrorString(WSAGetLastError()));
In commit “p2p: Bare minimum to support UNIX sockets”
Any reason this error is translated while others are not?
2103+ strError = "Unable to bind to UNIX socket " + path.string();
2104+ LogPrintf("%s\n", strError);
2105+ return false;
2106+ }
2107+ SOCKET hListenSocket = (SOCKET)fd;
2108+ LogPrintf("P2P bound to %s\n", path.string());
In commit “p2p: Bare minimum to support UNIX sockets”
Maybe mention path is unix socket path
utACK 9abf3c9da2c9e8e90b813ee379c7b8ff16a8f550, though many files are out of date.
I’m wondering why this is labeled “bare minimum to support UNIX sockets” and when support seems pretty complete. Are there other p2p features over unix sockets that you’d want to support?
Thanks for reviewing @JeremyRubin @jnewbery
though many files are out of date.
I somewhat dread having to rebase this, but hope to do so in the near future.
I’m wondering why this is labeled “bare minimum to support UNIX sockets” and when support seems pretty complete. Are there other p2p features over unix sockets that you’d want to support?
There’s no support in RPC calls yet, for example. Unix sockets can only be passed on the command line.
I somewhat dread having to rebase this, but hope to do so in the near future.
Yes - rebase looks like it’s going to be a big job :(
Let me know if I can help in any way - I’m definitely interested in getting Unix socket support for RPC.
I somewhat dread having to rebase this, but hope to do so in the near future.
I didn’t try rebasing, but the merge with master doesn’t look bad at all. The only C++ code conflicts are mapMultiArgs -> gArgs replacements. There is a huge scary looking conflict in the test framework util.py, but it just comes from the initialize_chain function moving to another file, and the changes there are minor.
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