extend core proxy options and handling #4871

• rework the proxy handling in init to cover more cases and work more thoroughly
• extend RPC call getnetwork info to see if IPv6 and Tor proxy is the default proxy

See #2575 for discussion!

@laanwj As you suggested, a new and clean pull and empty discussion ;).

@laanwj Can you please have a look again, I hope we can sort this out now finally :).

Automatic sanity-testing: PASSED, see http://jenkins.bluematt.me/pull-tester/p4871_2711cda5b8c54efb2164d7bb3593b3db50f8e15c/ for binaries and test log. This test script verifies pulls every time they are updated. It, however, dies sometimes and fails to test properly. If you are waiting on a test, please check timestamps to verify that the test.log is moving at http://jenkins.bluematt.me/pull-tester/current/ Contact BlueMatt on freenode if something looks broken.

Rebased and removed an obsolete c_str().

@laanwj This and the GUI part are pulls that are not cosmetic, but need review or ACKs.

Updated to include changes that were merged in #5358. @gmaxwell Mind reviewing this now?

Needs rebase

Rebased, needs review / testing.

To be clear what this is blocked on: We need (RPC) tests for the proxy functionality, before we can merge changes like this.

@laanwj Rebased to include the recent -proxyrandomize change. Also as a proxy test was added, this should be less controversial if tests pass I guess :).

@laanwj Removed changes to rpcnet.cpp.

@laanwj This is passing proxy tests and I removed what you didn't like. Anything I can do to get this forward finally?

I'm terribly sorry sorry for holding this up so long, but I'm not convinced that the new logic is any better.

The logical flow here sounds to me:

• Parse default -proxy, apply to all nets, as well as the name proxy
• Parse onion-specific proxy -onion, apply to NET_TOR. This overrides the default set in the first step, if any

All errors during parsing of either setting should be fatal, to avoid that the user is running with different settings than they expect.

This is nearer to the original code than yours. I certainly think the code could be simplified and made more clear, what do you think about:

    bool proxyRandomize = GetBoolArg("-proxyrandomize", true);
    // -proxy sets a proxy for all outgoing network traffic
    // -noproxy (or -proxy=0) as well as the empty string can be used to not set a proxy, this is the default
    std::string proxyArg = GetArg("-proxy", "");
    if (proxyArg != "" && proxyArg != "0") {
        proxyType addrProxy = proxyType(CService(proxyArg, 9050), proxyRandomize);
        if (!addrProxy.IsValid())
            return InitError(strprintf(_("Invalid -proxy address: '%s'"), proxyArg));

        SetProxy(NET_IPV4, addrProxy);
        SetProxy(NET_IPV6, addrProxy);
        SetProxy(NET_TOR, addrProxy);
        SetNameProxy(addrProxy);
        SetReachable(NET_TOR); // by default, -proxy sets onion as reachable, unless -noonion later
    }

    // -onion can override normal proxy for .onion addresses
    // -noonion (or -onion=0) disables connecting to .onion entirely
    // An empty string is used to just not override the onion proxy
    std::string onionArg = GetArg("-onion", "");
    if (onionArg != "") {
        if (onionArg == "0") { // Handle -noonion/-onion=0
            SetReachable(NET_TOR, false); // set onions as unreachable
        } else {
            proxyType addrOnion;
            addrOnion = proxyType(CService(onionArg, 9050), proxyRandomize);
            if (!addrOnion.IsValid())
                return InitError(strprintf(_("Invalid -onion address: '%s'"), onionArg));
            SetProxy(NET_TOR, addrOnion);
            SetReachable(NET_TOR);
        }
    }

This provides a straightforward flow, gets rid of .count() (which is what you needed for the GUI, as it makes it possible to override an earlier provided proxy option to nothing), as well as comments the different cases.

Closing in favor of #6272