lokinet/llarp/config/config.cpp

#include <chrono>
#include "config.hpp"

#include "config/definition.hpp"
#include "ini.hpp"
#include <llarp/constants/files.hpp>
#include <llarp/constants/platform.hpp>
#include <llarp/constants/version.hpp>
#include <llarp/net/net.hpp>
#include <llarp/net/ip.hpp>
#include <llarp/router_contact.hpp>
#include <stdexcept>
#include <llarp/util/file.hpp>
#include <llarp/util/formattable.hpp>
#include <llarp/util/logging.hpp>
#include <llarp/util/mem.hpp>
#include <llarp/util/str.hpp>

#include <llarp/service/name.hpp>

#include <cstdlib>
#include <ios>
#include <iostream>

namespace llarp
{
  // constants for config file default values
  constexpr int DefaultMinConnectionsForRouter = 6;
  constexpr int DefaultMaxConnectionsForRouter = 60;

  constexpr int DefaultMinConnectionsForClient = 4;
  constexpr int DefaultMaxConnectionsForClient = 6;

  constexpr int DefaultPublicPort = 1090;

  using namespace config;
  namespace
  {
    struct ConfigGenParameters_impl : public ConfigGenParameters
    {
      const llarp::net::Platform*
      Net_ptr() const
      {
        return llarp::net::Platform::Default_ptr();
      }
    };
  }  // namespace

  void
  RouterConfig::defineConfigOptions(ConfigDefinition& conf, const ConfigGenParameters& params)
  {
    constexpr Default DefaultJobQueueSize{1024 * 8};
    constexpr Default DefaultWorkerThreads{0};
    constexpr Default DefaultBlockBogons{true};

    conf.defineOption<int>(
        "router", "job-queue-size", DefaultJobQueueSize, Hidden, [this](int arg) {
          if (arg < 1024)
            throw std::invalid_argument("job-queue-size must be 1024 or greater");

          m_JobQueueSize = arg;
        });

    conf.defineOption<std::string>(
        "router",
        "netid",
        Default{llarp::DEFAULT_NETID},
        Comment{
            "Network ID; this is '"s + llarp::DEFAULT_NETID + "' for mainnet, 'gamma' for testnet.",
        },
        [this](std::string arg) {
          if (arg.size() > NetID::size())
            throw std::invalid_argument{
                fmt::format("netid is too long, max length is {}", NetID::size())};

          m_netId = std::move(arg);
        });

    int minConnections =
        (params.isRelay ? DefaultMinConnectionsForRouter : DefaultMinConnectionsForClient);
    conf.defineOption<int>(
        "router",
        "min-connections",
        Default{minConnections},
        Comment{
            "Minimum number of routers lokinet will attempt to maintain connections to.",
        },
        [=](int arg) {
          if (arg < minConnections)
            throw std::invalid_argument{
                fmt::format("min-connections must be >= {}", minConnections)};

          m_minConnectedRouters = arg;
        });

    int maxConnections =
        (params.isRelay ? DefaultMaxConnectionsForRouter : DefaultMaxConnectionsForClient);
    conf.defineOption<int>(
        "router",
        "max-connections",
        Default{maxConnections},
        Comment{
            "Maximum number (hard limit) of routers lokinet will be connected to at any time.",
        },
        [=](int arg) {
          if (arg < maxConnections)
            throw std::invalid_argument{
                fmt::format("max-connections must be >= {}", maxConnections)};

          m_maxConnectedRouters = arg;
        });

    conf.defineOption<std::string>("router", "nickname", Hidden, AssignmentAcceptor(m_nickname));

    conf.defineOption<fs::path>(
        "router",
        "data-dir",
        Default{params.defaultDataDir},
        Comment{
            "Optional directory for containing lokinet runtime data. This includes generated",
            "private keys.",
        },
        [this](fs::path arg) {
          if (arg.empty())
            throw std::invalid_argument("[router]:data-dir is empty");
          if (not fs::exists(arg))
            throw std::runtime_error{
                fmt::format("Specified [router]:data-dir {} does not exist", arg)};

          m_dataDir = std::move(arg);
        });

    conf.defineOption<std::string>(
        "router",
        "public-ip",
        RelayOnly,
        Comment{
            "For complex network configurations where the detected IP is incorrect or non-public",
            "this setting specifies the public IP at which this router is reachable. When",
            "provided the public-port option must also be specified.",
        },
        [this, net = params.Net_ptr()](std::string arg) {
          if (arg.empty())
            return;
          nuint32_t addr{};
          if (not addr.FromString(arg))
            throw std::invalid_argument{fmt::format("{} is not a valid IPv4 address", arg)};

          if (net->IsBogonIP(addr))
            throw std::invalid_argument{
                fmt::format("{} is not a publicly routable ip address", addr)};

          PublicIP = addr;
        });

    conf.defineOption<std::string>("router", "public-address", Hidden, [](std::string) {
      throw std::invalid_argument{
          "[router]:public-address option no longer supported, use [router]:public-ip and "
          "[router]:public-port instead"};
    });

    conf.defineOption<int>(
        "router",
        "public-port",
        RelayOnly,
        Default{DefaultPublicPort},
        Comment{
            "When specifying public-ip=, this specifies the public UDP port at which this lokinet",
            "router is reachable. Required when public-ip is used.",
        },
        [this](int arg) {
          if (arg <= 0 || arg > std::numeric_limits<uint16_t>::max())
            throw std::invalid_argument("public-port must be >= 0 and <= 65536");
          PublicPort = ToNet(huint16_t{static_cast<uint16_t>(arg)});
        });

    conf.defineOption<int>(
        "router",
        "worker-threads",
        DefaultWorkerThreads,
        Comment{
            "The number of threads available for performing cryptographic functions.",
            "The minimum is one thread, but network performance may increase with more.",
            "threads. Should not exceed the number of logical CPU cores.",
            "0 means use the number of logical CPU cores detected at startup.",
        },
        [this](int arg) {
          if (arg < 0)
            throw std::invalid_argument("worker-threads must be >= 0");

          m_workerThreads = arg;
        });

    // Hidden option because this isn't something that should ever be turned off occasionally when
    // doing dev/testing work.
    conf.defineOption<bool>(
        "router", "block-bogons", DefaultBlockBogons, Hidden, AssignmentAcceptor(m_blockBogons));

    constexpr auto relative_to_datadir =
        "An absolute path is used as-is, otherwise relative to 'data-dir'.";

    conf.defineOption<std::string>(
        "router",
        "contact-file",
        RelayOnly,
        Default{llarp::our_rc_filename},
        AssignmentAcceptor(m_routerContactFile),
        Comment{
            "Filename in which to store the router contact file",
            relative_to_datadir,
        });

    conf.defineOption<std::string>(
        "router",
        "encryption-privkey",
        RelayOnly,
        Default{llarp::our_enc_key_filename},
        AssignmentAcceptor(m_encryptionKeyFile),
        Comment{
            "Filename in which to store the encryption private key",
            relative_to_datadir,
        });

    conf.defineOption<std::string>(
        "router",
        "ident-privkey",
        RelayOnly,
        Default{llarp::our_identity_filename},
        AssignmentAcceptor(m_identityKeyFile),
        Comment{
            "Filename in which to store the identity private key",
            relative_to_datadir,
        });

    conf.defineOption<std::string>(
        "router",
        "transport-privkey",
        RelayOnly,
        Default{llarp::our_transport_key_filename},
        AssignmentAcceptor(m_transportKeyFile),
        Comment{
            "Filename in which to store the transport private key.",
            relative_to_datadir,
        });

    // Deprecated options:

    // these weren't even ever used!
    conf.defineOption<std::string>("router", "max-routers", Deprecated);
    conf.defineOption<std::string>("router", "min-routers", Deprecated);

    // TODO: this may have been a synonym for [router]worker-threads
    conf.defineOption<std::string>("router", "threads", Deprecated);
    conf.defineOption<std::string>("router", "net-threads", Deprecated);

    m_isRelay = params.isRelay;
  }

  void
  NetworkConfig::defineConfigOptions(ConfigDefinition& conf, const ConfigGenParameters& params)
  {
    (void)params;

    static constexpr Default ProfilingValueDefault{true};
    static constexpr Default SaveProfilesDefault{true};
    static constexpr Default ReachableDefault{true};
    static constexpr Default HopsDefault{4};
    static constexpr Default PathsDefault{6};
    static constexpr Default IP6RangeDefault{"fd00::"};

    conf.defineOption<std::string>(
        "network", "type", Default{"tun"}, Hidden, AssignmentAcceptor(m_endpointType));

    conf.defineOption<bool>(
        "network",
        "save-profiles",
        SaveProfilesDefault,
        Hidden,
        AssignmentAcceptor(m_saveProfiles));

    conf.defineOption<bool>(
        "network",
        "profiling",
        ProfilingValueDefault,
        Hidden,
        AssignmentAcceptor(m_enableProfiling));

    conf.defineOption<std::string>("network", "profiles", Deprecated);

    conf.defineOption<std::string>(
        "network",
        "strict-connect",
        ClientOnly,
        MultiValue,
        [this](std::string value) {
          RouterID router;
          if (not router.FromString(value))
            throw std::invalid_argument{"bad snode value: " + value};
          if (not m_strictConnect.insert(router).second)
            throw std::invalid_argument{"duplicate strict connect snode: " + value};
        },
        Comment{
            "Public keys of routers which will act as pinned first-hops. This may be used to",
            "provide a trusted router (consider that you are not fully anonymous with your",
            "first hop).  This REQUIRES two or more nodes to be specified.",
        });

    conf.defineOption<std::string>(
        "network",
        "keyfile",
        ClientOnly,
        AssignmentAcceptor(m_keyfile),
        Comment{
            "The private key to persist address with. If not specified the address will be",
            "ephemeral.",
        });

    conf.defineOption<std::string>(
        "network",
        "auth",
        ClientOnly,
        Comment{
            "Set the endpoint authentication mechanism.",
            "none/whitelist/lmq/file",
        },
        [this](std::string arg) {
          if (arg.empty())
            return;
          m_AuthType = service::ParseAuthType(arg);
        });

    conf.defineOption<std::string>(
        "network",
        "auth-lmq",
        ClientOnly,
        AssignmentAcceptor(m_AuthUrl),
        Comment{
            "lmq endpoint to talk to for authenticating new sessions",
            "ipc:///var/lib/lokinet/auth.socket",
            "tcp://127.0.0.1:5555",
        });

    conf.defineOption<std::string>(
        "network",
        "auth-lmq-method",
        ClientOnly,
        Default{"llarp.auth"},
        Comment{
            "lmq function to call for authenticating new sessions",
            "llarp.auth",
        },
        [this](std::string arg) {
          if (arg.empty())
            return;
          m_AuthMethod = std::move(arg);
        });

    conf.defineOption<std::string>(
        "network",
        "auth-whitelist",
        ClientOnly,
        MultiValue,
        Comment{
            "manually add a remote endpoint by .loki address to the access whitelist",
        },
        [this](std::string arg) {
          service::Address addr;
          if (not addr.FromString(arg))
            throw std::invalid_argument{fmt::format("bad loki address: {}", arg)};
          m_AuthWhitelist.emplace(std::move(addr));
        });

    conf.defineOption<fs::path>(
        "network",
        "auth-file",
        ClientOnly,
        MultiValue,
        Comment{
            "Read auth tokens from file to accept endpoint auth",
            "Can be provided multiple times",
        },
        [this](fs::path arg) {
          if (not fs::exists(arg))
            throw std::invalid_argument{
                fmt::format("cannot load auth file {}: file does not exist", arg)};
          m_AuthFiles.emplace(std::move(arg));
        });
    conf.defineOption<std::string>(
        "network",
        "auth-file-type",
        ClientOnly,
        Comment{
            "How to interpret the contents of an auth file.",
            "Possible values: hashes, plaintext",
        },
        [this](std::string arg) { m_AuthFileType = service::ParseAuthFileType(std::move(arg)); });

    conf.defineOption<std::string>(
        "network",
        "auth-static",
        ClientOnly,
        MultiValue,
        Comment{
            "Manually add a static auth code to accept for endpoint auth",
            "Can be provided multiple times",
        },
        [this](std::string arg) { m_AuthStaticTokens.emplace(std::move(arg)); });

    conf.defineOption<bool>(
        "network",
        "reachable",
        ClientOnly,
        ReachableDefault,
        AssignmentAcceptor(m_reachable),
        Comment{
            "Determines whether we will pubish our snapp's introset to the DHT.",
        });

    conf.defineOption<int>(
        "network",
        "hops",
        HopsDefault,
        Comment{
            "Number of hops in a path. Min 1, max 8.",
        },
        [this](int arg) {
          if (arg < 1 or arg > 8)
            throw std::invalid_argument("[endpoint]:hops must be >= 1 and <= 8");
          m_Hops = arg;
        });

    conf.defineOption<int>(
        "network",
        "paths",
        ClientOnly,
        PathsDefault,
        Comment{
            "Number of paths to maintain at any given time.",
        },
        [this](int arg) {
          if (arg < 3 or arg > 8)
            throw std::invalid_argument("[endpoint]:paths must be >= 3 and <= 8");
          m_Paths = arg;
        });

    conf.defineOption<bool>(
        "network",
        "exit",
        ClientOnly,
        Default{false},
        AssignmentAcceptor(m_AllowExit),
        Comment{
            "Whether or not we should act as an exit node. Beware that this increases demand",
            "on the server and may pose liability concerns. Enable at your own risk.",
        });

    conf.defineOption<std::string>(
        "network",
        "owned-range",
        MultiValue,
        Comment{
            "When in exit mode announce we allow a private range in our introset.  For example:",
            "    owned-range=10.0.0.0/24",
        },
        [this](std::string arg) {
          IPRange range;
          if (not range.FromString(arg))
            throw std::invalid_argument{"bad ip range: '" + arg + "'"};
          m_OwnedRanges.insert(range);
        });

    conf.defineOption<std::string>(
        "network",
        "traffic-whitelist",
        MultiValue,
        Comment{
            "Adds an IP traffic type whitelist; can be specified multiple times.  If any are",
            "specified then only matched traffic will be allowed and all other traffic will be",
            "dropped.  Examples:",
            "    traffic-whitelist=tcp",
            "would allow all TCP/IP packets (regardless of port);",
            "    traffic-whitelist=0x69",
            "would allow IP traffic with IP protocol 0x69;",
            "    traffic-whitelist=udp/53",
            "would allow UDP port 53; and",
            "    traffic-whitelist=tcp/smtp",
            "would allow TCP traffic on the standard smtp port (21).",
        },
        [this](std::string arg) {
          if (not m_TrafficPolicy)
            m_TrafficPolicy = net::TrafficPolicy{};

          // this will throw on error
          m_TrafficPolicy->protocols.emplace(arg);
        });

    conf.defineOption<std::string>(
        "network",
        "exit-node",
        ClientOnly,
        MultiValue,
        Comment{
            "Specify a `.loki` address and an optional ip range to use as an exit broker.",
            "Examples:",
            "    exit-node=whatever.loki",
            "would map all exit traffic through whatever.loki; and",
            "    exit-node=stuff.loki:100.0.0.0/24",
            "would map the IP range 100.0.0.0/24 through stuff.loki.",
            "This option can be specified multiple times (to map different IP ranges).",
        },
        [this](std::string arg) {
          if (arg.empty())
            return;
          service::Address exit;
          IPRange range;
          const auto pos = arg.find(":");
          if (pos == std::string::npos)
          {
            range.FromString("::/0");
          }
          else if (not range.FromString(arg.substr(pos + 1)))
          {
            throw std::invalid_argument("[network]:exit-node invalid ip range for exit provided");
          }
          if (pos != std::string::npos)
          {
            arg = arg.substr(0, pos);
          }

          if (service::NameIsValid(arg))
          {
            m_LNSExitMap.Insert(range, arg);
            return;
          }

          if (arg != "null" and not exit.FromString(arg))
          {
            throw std::invalid_argument{fmt::format("[network]:exit-node bad address: {}", arg)};
          }
          m_ExitMap.Insert(range, exit);
        });

    conf.defineOption<std::string>(
        "network",
        "exit-auth",
        ClientOnly,
        MultiValue,
        Comment{
            "Specify an optional authentication code required to use a non-public exit node.",
            "For example:",
            "    exit-auth=myfavouriteexit.loki:abc",
            "uses the authentication code `abc` whenever myfavouriteexit.loki is accessed.",
            "Can be specified multiple times to store codes for different exit nodes.",
        },
        [this](std::string arg) {
          if (arg.empty())
            return;
          service::Address exit;
          service::AuthInfo auth;
          const auto pos = arg.find(":");
          if (pos == std::string::npos)
          {
            throw std::invalid_argument(
                "[network]:exit-auth invalid format, expects "
                "exit-address.loki:auth-code-goes-here");
          }
          const auto exit_str = arg.substr(0, pos);
          auth.token = arg.substr(pos + 1);

          if (service::NameIsValid(exit_str))
          {
            m_LNSExitAuths.emplace(exit_str, auth);
            return;
          }

          if (not exit.FromString(exit_str))
          {
            throw std::invalid_argument("[network]:exit-auth invalid exit address");
          }
          m_ExitAuths.emplace(exit, auth);
        });

    conf.defineOption<bool>(
        "network",
        "auto-routing",
        ClientOnly,
        Default{true},
        Comment{
            "Enable / disable automatic route configuration.",
            "When this is enabled and an exit is used Lokinet will automatically configure the",
            "operating system routes to route public internet traffic through the exit node.",
            "This is enabled by default, but can be disabled if advanced/manual exit routing",
            "configuration is desired."},
        AssignmentAcceptor(m_EnableRoutePoker));

    conf.defineOption<bool>(
        "network",
        "blackhole-routes",
        ClientOnly,
        Default{true},
        Comment{
            "Enable / disable route configuration blackholes.",
            "When enabled lokinet will drop IPv4 and IPv6 traffic (when in exit mode) that is not",
            "handled in the exit configuration.  Enabled by default."},
        AssignmentAcceptor(m_BlackholeRoutes));

    conf.defineOption<std::string>(
        "network",
        "ifname",
        Comment{
            "Interface name for lokinet traffic. If unset lokinet will look for a free name",
            "matching 'lokinetN', starting at N=0 (e.g. lokinet0, lokinet1, ...).",
        },
        AssignmentAcceptor(m_ifname));

    conf.defineOption<std::string>(
        "network",
        "ifaddr",
        Comment{
            "Local IP and range for lokinet traffic. For example, 172.16.0.1/16 to use",
            "172.16.0.1 for this machine and 172.16.x.y for remote peers. If omitted then",
            "lokinet will attempt to find an unused private range.",
        },
        [this](std::string arg) {
          if (not m_ifaddr.FromString(arg))
          {
            throw std::invalid_argument{fmt::format("[network]:ifaddr invalid value: '{}'", arg)};
          }
        });

    conf.defineOption<std::string>(
        "network",
        "ip6-range",
        ClientOnly,
        Comment{
            "For all IPv6 exit traffic you will use this as the base address bitwised or'd with ",
            "the v4 address in use.",
            "To disable ipv6 set this to an empty value.",
            "!!! WARNING !!! Disabling ipv6 tunneling when you have ipv6 routes WILL lead to ",
            "de-anonymization as lokinet will no longer carry your ipv6 traffic.",
        },
        IP6RangeDefault,
        [this](std::string arg) {
          if (arg.empty())
          {
            LogError(
                "!!! Disabling ipv6 tunneling when you have ipv6 routes WILL lead to "
                "de-anonymization as lokinet will no longer carry your ipv6 traffic !!!");
            m_baseV6Address = std::nullopt;
            return;
          }
          m_baseV6Address = huint128_t{};
          if (not m_baseV6Address->FromString(arg))
            throw std::invalid_argument{
                fmt::format("[network]:ip6-range invalid value: '{}'", arg)};
        });

    // TODO: could be useful for snodes in the future, but currently only implemented for clients:
    conf.defineOption<std::string>(
        "network",
        "mapaddr",
        ClientOnly,
        MultiValue,
        Comment{
            "Map a remote `.loki` address to always use a fixed local IP. For example:",
            "    mapaddr=whatever.loki:172.16.0.10",
            "maps `whatever.loki` to `172.16.0.10` instead of using the next available IP.",
            "The given IP address must be inside the range configured by ifaddr=",
        },
        [this](std::string arg) {
          if (arg.empty())
            return;
          huint128_t ip;
          service::Address addr;
          const auto pos = arg.find(":");
          if (pos == std::string::npos)
          {
            throw std::invalid_argument{fmt::format("[endpoint]:mapaddr invalid entry: {}", arg)};
          }
          std::string addrstr = arg.substr(0, pos);
          std::string ipstr = arg.substr(pos + 1);
          if (not ip.FromString(ipstr))
          {
            huint32_t ipv4;
            if (not ipv4.FromString(ipstr))
            {
              throw std::invalid_argument{fmt::format("[endpoint]:mapaddr invalid ip: {}", ipstr)};
            }
            ip = net::ExpandV4(ipv4);
          }
          if (not addr.FromString(addrstr))
          {
            throw std::invalid_argument{
                fmt::format("[endpoint]:mapaddr invalid addresss: {}", addrstr)};
          }
          if (m_mapAddrs.find(ip) != m_mapAddrs.end())
          {
            throw std::invalid_argument{
                fmt::format("[endpoint]:mapaddr ip already mapped: {}", ipstr)};
          }
          m_mapAddrs[ip] = addr;
        });

    conf.defineOption<std::string>(
        "network",
        "blacklist-snode",
        ClientOnly,
        MultiValue,
        Comment{
            "Adds a lokinet relay `.snode` address to the list of relays to avoid when",
            "building paths. Can be specified multiple times.",
        },
        [this](std::string arg) {
          RouterID id;
          if (not id.FromString(arg))
            throw std::invalid_argument{fmt::format("Invalid RouterID: {}", arg)};

          auto itr = m_snodeBlacklist.emplace(std::move(id));
          if (not itr.second)
            throw std::invalid_argument{fmt::format("Duplicate blacklist-snode: {}", arg)};
        });

    // TODO: support SRV records for routers, but for now client only
    conf.defineOption<std::string>(
        "network",
        "srv",
        ClientOnly,
        MultiValue,
        Comment{
            "Specify SRV Records for services hosted on the SNApp for protocols that use SRV",
            "records for service discovery. Each line specifies a single SRV record as:",
            "    srv=_service._protocol priority weight port target.loki",
            "and can be specified multiple times as needed.",
            "For more info see",
            "https://docs.oxen.io/products-built-on-oxen/lokinet/snapps/hosting-snapps",
            "and general description of DNS SRV record configuration.",
        },
        [this](std::string arg) {
          llarp::dns::SRVData newSRV;
          if (not newSRV.fromString(arg))
            throw std::invalid_argument{fmt::format("Invalid SRV Record string: {}", arg)};

          m_SRVRecords.push_back(std::move(newSRV));
        });

    conf.defineOption<int>(
        "network",
        "path-alignment-timeout",
        ClientOnly,
        Comment{
            "How long to wait (in seconds) for a path to align to a pivot router when establishing",
            "a path through the network to a remote .loki address.",
        },
        [this](int val) {
          if (val <= 0)
            throw std::invalid_argument{
                "invalid path alignment timeout: " + std::to_string(val) + " <= 0"};
          m_PathAlignmentTimeout = std::chrono::seconds{val};
        });

    conf.defineOption<fs::path>(
        "network",
        "persist-addrmap-file",
        ClientOnly,
        Default{fs::path{params.defaultDataDir / "addrmap.dat"}},
        Comment{
            "If given this specifies a file in which to record mapped local tunnel addresses so",
            "the same local address will be used for the same lokinet address on reboot.  If this",
            "is not specified then the local IP of remote lokinet targets will not persist across",
            "restarts of lokinet.",
        },
        [this](fs::path arg) {
          if (arg.empty())
            throw std::invalid_argument("persist-addrmap-file cannot be empty");
          m_AddrMapPersistFile = arg;
        });

    // Deprecated options:
    conf.defineOption<std::string>("network", "enabled", Deprecated);
  }

  void
  DnsConfig::defineConfigOptions(ConfigDefinition& conf, const ConfigGenParameters& params)
  {
    (void)params;

    // Most non-linux platforms have loopback as 127.0.0.1/32, but linux uses 127.0.0.1/8 so that we
    // can bind to other 127.* IPs to avoid conflicting with something else that may be listening on
    // 127.0.0.1:53.
    constexpr std::array DefaultDNSBind{
#ifdef __linux__
#ifdef WITH_SYSTEMD
        // when we have systemd support add a random high port on loopback as well
        // see https://github.com/oxen-io/lokinet/issues/1887#issuecomment-1091897282
        Default{"127.0.0.1:0"},
#endif
        Default{"127.3.2.1:53"},
#else
        Default{"127.0.0.1:53"},
#endif
    };

    // Default, but if we get any upstream (including upstream=, i.e. empty string) we clear it
    constexpr Default DefaultUpstreamDNS{"9.9.9.10:53"};
    m_upstreamDNS.emplace_back(DefaultUpstreamDNS.val);

    conf.defineOption<std::string>(
        "dns",
        "upstream",
        MultiValue,
        Comment{
            "Upstream resolver(s) to use as fallback for non-loki addresses.",
            "Multiple values accepted.",
        },
        [=, first = true](std::string arg) mutable {
          if (first)
          {
            m_upstreamDNS.clear();
            first = false;
          }
          if (not arg.empty())
          {
            auto& entry = m_upstreamDNS.emplace_back(std::move(arg));
            if (not entry.getPort())
              entry.setPort(53);
          }
        });

    conf.defineOption<bool>(
        "dns",
        "l3-intercept",
        Default{
            platform::is_windows or platform::is_android
            or (platform::is_macos and not platform::is_apple_sysex)},
        Comment{"Intercept all dns traffic (udp/53) going into our lokinet network interface "
                "instead of binding a local udp socket"},
        AssignmentAcceptor(m_raw_dns));

    conf.defineOption<std::string>(
        "dns",
        "query-bind",
#if defined(_WIN32)
        Default{"0.0.0.0:0"},
#else
        Hidden,
#endif
        Comment{
            "Address to bind to for sending upstream DNS requests.",
        },
        [this](std::string arg) { m_QueryBind = SockAddr{arg}; });

    conf.defineOption<std::string>(
        "dns",
        "bind",
        DefaultDNSBind,
        MultiValue,
        Comment{
            "Address to bind to for handling DNS requests.",
        },
        [=](std::string arg) {
          SockAddr addr{arg};
          // set dns port if no explicit port specified
          // explicit :0 allowed
          if (not addr.getPort() and not ends_with(arg, ":0"))
            addr.setPort(53);
          m_bind.emplace_back(addr);
        });

    conf.defineOption<fs::path>(
        "dns",
        "add-hosts",
        ClientOnly,
        Comment{"Add a hosts file to the dns resolver", "For use with client side dns filtering"},
        [=](fs::path path) {
          if (path.empty())
            return;
          if (not fs::exists(path))
            throw std::invalid_argument{
                fmt::format("cannot add hosts file {} as it does not exist", path)};
          m_hostfiles.emplace_back(std::move(path));
        });

    // Ignored option (used by the systemd service file to disable resolvconf configuration).
    conf.defineOption<bool>(
        "dns",
        "no-resolvconf",
        ClientOnly,
        Comment{
            "Can be uncommented and set to 1 to disable resolvconf configuration of lokinet DNS.",
            "(This is not used directly by lokinet itself, but by the lokinet init scripts",
            "on systems which use resolveconf)",
        });

    // forward the rest to libunbound
    conf.addUndeclaredHandler("dns", [this](auto, std::string_view key, std::string_view val) {
      m_ExtraOpts.emplace(key, val);
    });
  }

  void
  LinksConfig::defineConfigOptions(ConfigDefinition& conf, const ConfigGenParameters& params)
  {
    conf.addSectionComments(
        "bind",
        {
            "This section allows specifying the IPs that lokinet uses for incoming and outgoing",
            "connections.  For simple setups it can usually be left blank, but may be required",
            "for routers with multiple IPs, or routers that must listen on a private IP with",
            "forwarded public traffic.  It can also be useful for clients that want to use a",
            "consistent outgoing port for which firewall rules can be configured.",
        });

    const auto* net_ptr = params.Net_ptr();

    static constexpr Default DefaultInboundPort{uint16_t{1090}};
    static constexpr Default DefaultOutboundPort{uint16_t{0}};

    conf.defineOption<std::string>(
        "bind",
        "public-ip",
        RelayOnly,
        Comment{
            "The IP address to advertise to the network instead of the incoming= or auto-detected",
            "IP.  This is typically required only when incoming= is used to listen on an internal",
            "private range IP address that received traffic forwarded from the public IP.",
        },
        [this](std::string_view arg) {
          SockAddr pubaddr{arg};
          PublicAddress = pubaddr.getIP();
        });
    conf.defineOption<uint16_t>(
        "bind",
        "public-port",
        RelayOnly,
        Comment{
            "The port to advertise to the network instead of the incoming= (or default) port.",
            "This is typically required only when incoming= is used to listen on an internal",
            "private range IP address/port that received traffic forwarded from the public IP.",
        },
        [this](uint16_t arg) { PublicPort = net::port_t::from_host(arg); });

    auto parse_addr_for_link = [net_ptr](
                                   const std::string& arg, net::port_t default_port, bool inbound) {
      std::optional<SockAddr> addr = std::nullopt;
      // explicitly provided value
      if (not arg.empty())
      {
        if (arg[0] == ':')
        {
          // port only case
          default_port = net::port_t::from_string(arg.substr(1));
          if (!inbound)
            addr = net_ptr->WildcardWithPort(default_port);
        }
        else
        {
          addr = SockAddr{arg};
          if (net_ptr->IsLoopbackAddress(addr->getIP()))
            throw std::invalid_argument{fmt::format("{} is a loopback address", arg)};
        }
      }
      if (not addr)
      {
        // infer public address
        if (auto maybe_ifname = net_ptr->GetBestNetIF())
          addr = net_ptr->GetInterfaceAddr(*maybe_ifname);
      }

      if (addr)
      {
        // set port if not explicitly provided
        if (addr->getPort() == 0)
          addr->setPort(default_port);
      }
      return addr;
    };

    conf.defineOption<std::string>(
        "bind",
        "inbound",
        RelayOnly,
        MultiValue,
        Comment{
            "IP and/or port to listen on for incoming connections.",
            "",
            "If IP is omitted then lokinet will search for a local network interface with a",
            "public IP address and use that IP (and will exit with an error if no such IP is found",
            "on the system).  If port is omitted then lokinet defaults to 1090.",
            "",
            "Examples:",
            "    inbound=15.5.29.5:443",
            "    inbound=10.0.2.2",
            "    inbound=:1234",
            "",
            "Using a private range IP address (like the second example entry) will require using",
            "the public-ip= and public-port= to specify the public IP address at which this",
            "router can be reached.",
        },
        [this, parse_addr_for_link](const std::string& arg) {
          auto default_port = net::port_t::from_host(DefaultInboundPort.val);
          if (auto addr = parse_addr_for_link(arg, default_port, /*inbound=*/true))
            InboundListenAddrs.emplace_back(std::move(*addr));
        });

    conf.defineOption<std::string>(
        "bind",
        "outbound",
        MultiValue,
        params.isRelay ? Comment{
            "IP and/or port to use for outbound socket connections to other lokinet routers.",
            "",
            "If no outbound bind IP is configured, or the 0.0.0.0 wildcard IP is given, then",
            "lokinet will bind to the same IP being used for inbound connections (either an",
            "explicit inbound= provided IP, or the default).  If no port is given, or port is",
            "given as 0, then a random high port will be used.",
            "",
            "If using multiple inbound= addresses then you *must* provide an explicit oubound= IP.",
            "",
            "Examples:",
            "    outbound=1.2.3.4:5678",
            "    outbound=:9000",
            "    outbound=8.9.10.11",
            "",
            "The second example binds on the default incoming IP using port 9000; the third",
            "example binds on the given IP address using a random high port.",
        } : Comment{
            "IP and/or port to use for outbound socket connections to lokinet routers.",
            "",
            "If no outbound bind IP is configured then lokinet will use a wildcard IP address",
            "(equivalent to specifying 0.0.0.0).  If no port is given then a random high port",
            "will be used.",
            "",
            "Examples:",
            "    outbound=1.2.3.4:5678",
            "    outbound=:9000",
            "    outbound=8.9.10.11",
            "",
            "The second example binds on the wildcard address using port 9000; the third example",
            "binds on the given IP address using a random high port.",
        },
        [this, net_ptr, parse_addr_for_link](const std::string& arg) {
          auto default_port = net::port_t::from_host(DefaultOutboundPort.val);
          auto addr = parse_addr_for_link(arg, default_port, /*inbound=*/false);
          if (not addr)
            addr = net_ptr->WildcardWithPort(default_port);
          OutboundLinks.emplace_back(std::move(*addr));
        });

    conf.addUndeclaredHandler(
        "bind", [this, net_ptr](std::string_view, std::string_view key, std::string_view val) {
          LogWarn(
              "using the [bind] section with *=/IP=/INTERFACE= is deprecated; use the inbound= "
              "and/or outbound= settings instead");
          std::optional<SockAddr> addr;
          // special case: wildcard for outbound
          if (key == "*")
          {
            addr = net_ptr->Wildcard();
            // set port, zero is acceptable here.
            if (auto port = std::stoi(std::string{val});
                port < std::numeric_limits<uint16_t>::max())
            {
              addr->setPort(port);
            }
            else
              throw std::invalid_argument{fmt::format("invalid port value: '{}'", val)};
            OutboundLinks.emplace_back(std::move(*addr));
            return;
          }
          // try as interface name first
          addr = net_ptr->GetInterfaceAddr(key, AF_INET);
          if (addr and net_ptr->IsLoopbackAddress(addr->getIP()))
            throw std::invalid_argument{fmt::format("{} is a loopback interface", key)};
          // try as ip address next, throws if unable to parse
          if (not addr)
          {
            addr = SockAddr{key, huint16_t{0}};
            if (net_ptr->IsLoopbackAddress(addr->getIP()))
              throw std::invalid_argument{fmt::format("{} is a loopback address", key)};
          }
          // parse port and set if acceptable non zero value
          if (auto port = std::stoi(std::string{val});
              port and port < std::numeric_limits<uint16_t>::max())
          {
            addr->setPort(port);
          }
          else
            throw std::invalid_argument{fmt::format("invalid port value: '{}'", val)};

          InboundListenAddrs.emplace_back(std::move(*addr));
        });
  }

  void
  ConnectConfig::defineConfigOptions(ConfigDefinition& conf, const ConfigGenParameters& params)
  {
    (void)params;

    conf.addUndeclaredHandler(
        "connect", [this](std::string_view section, std::string_view name, std::string_view value) {
          fs::path file{value.begin(), value.end()};
          if (not fs::exists(file))
            throw std::runtime_error{fmt::format(
                "Specified bootstrap file {} specified in [{}]:{} does not exist",
                value,
                section,
                name)};

          routers.emplace_back(std::move(file));
          return true;
        });
  }

  void
  ApiConfig::defineConfigOptions(ConfigDefinition& conf, const ConfigGenParameters& params)
  {
    constexpr Default DefaultRPCBindAddr{"tcp://127.0.0.1:1190"};

    conf.defineOption<bool>(
        "api",
        "enabled",
        Default{not params.isRelay},
        AssignmentAcceptor(m_enableRPCServer),
        Comment{
            "Determines whether or not the LMQ JSON API is enabled. Defaults ",
        });

    conf.defineOption<std::string>(
        "api",
        "bind",
        DefaultRPCBindAddr,
        [this](std::string arg) {
          if (arg.empty())
          {
            arg = DefaultRPCBindAddr.val;
          }
          if (arg.find("://") == std::string::npos)
          {
            arg = "tcp://" + arg;
          }
          m_rpcBindAddr = std::move(arg);
        },
        Comment{
            "IP address and port to bind to.",
            "Recommend localhost-only for security purposes.",
        });

    conf.defineOption<std::string>("api", "authkey", Deprecated);

    // TODO: this was from pre-refactor:
    // TODO: add pubkey to whitelist
  }

  void
  LokidConfig::defineConfigOptions(ConfigDefinition& conf, const ConfigGenParameters& params)
  {
    (void)params;

    conf.defineOption<bool>(
        "lokid",
        "enabled",
        RelayOnly,
        Default{true},
        Comment{
            "Whether or not we should talk to oxend. Must be enabled for staked routers.",
        },
        AssignmentAcceptor(whitelistRouters));

    conf.defineOption<std::string>("lokid", "jsonrpc", RelayOnly, [](std::string arg) {
      if (arg.empty())
        return;
      throw std::invalid_argument(
          "the [lokid]:jsonrpc option is no longer supported; please use the [lokid]:rpc config "
          "option instead with oxend's lmq-local-control address -- typically a value such as "
          "rpc=ipc:///var/lib/oxen/oxend.sock or rpc=ipc:///home/snode/.oxen/oxend.sock");
    });

    conf.defineOption<std::string>(
        "lokid",
        "rpc",
        RelayOnly,
        Required,
        Comment{
            "oxenmq control address for for communicating with oxend. Depends on oxend's",
            "lmq-local-control configuration option. By default this value should be",
            "ipc://OXEND-DATA-DIRECTORY/oxend.sock, such as:",
            "    rpc=ipc:///var/lib/oxen/oxend.sock",
            "    rpc=ipc:///home/USER/.oxen/oxend.sock",
            "but can use (non-default) TCP if oxend is configured that way:",
            "    rpc=tcp://127.0.0.1:5678",
        },
        [this](std::string arg) { lokidRPCAddr = oxenmq::address(arg); });

    // Deprecated options:
    conf.defineOption<std::string>("lokid", "username", Deprecated);
    conf.defineOption<std::string>("lokid", "password", Deprecated);
    conf.defineOption<std::string>("lokid", "service-node-seed", Deprecated);
  }

  void
  BootstrapConfig::defineConfigOptions(ConfigDefinition& conf, const ConfigGenParameters& params)
  {
    (void)params;

    conf.defineOption<bool>(
        "bootstrap",
        "seed-node",
        Default{false},
        Comment{"Whether or not to run as a seed node. We will not have any bootstrap routers "
                "configured."},
        AssignmentAcceptor(seednode));

    conf.defineOption<std::string>(
        "bootstrap",
        "add-node",
        MultiValue,
        Comment{
            "Specify a bootstrap file containing a list of signed RouterContacts of service nodes",
            "which can act as a bootstrap. Can be specified multiple times.",
        },
        [this](std::string arg) {
          if (arg.empty())
          {
            throw std::invalid_argument("cannot use empty filename as bootstrap");
          }
          files.emplace_back(std::move(arg));
          if (not fs::exists(files.back()))
          {
            throw std::invalid_argument("file does not exist: " + arg);
          }
        });
  }

  void
  LoggingConfig::defineConfigOptions(ConfigDefinition& conf, const ConfigGenParameters& params)
  {
    (void)params;

    constexpr Default DefaultLogType{
        platform::is_android or platform::is_apple ? "system" : "print"};
    constexpr Default DefaultLogFile{""};

    const Default DefaultLogLevel{params.isRelay ? "warn" : "info"};

    conf.defineOption<std::string>(
        "logging",
        "type",
        DefaultLogType,
        [this](std::string arg) { m_logType = log::type_from_string(arg); },
        Comment{
            "Log type (format). Valid options are:",
            "  print - print logs to standard output",
            "  system - logs directed to the system logger (syslog/eventlog/etc.)",
            "  file - plaintext formatting to a file",
        });

    conf.defineOption<std::string>(
        "logging",
        "level",
        DefaultLogLevel,
        [this](std::string arg) { m_logLevel = log::level_from_string(arg); },
        Comment{
            "Minimum log level to print. Logging below this level will be ignored.",
            "Valid log levels, in ascending order, are:",
            "  trace",
            "  debug",
            "  info",
            "  warn",
            "  error",
            "  critical",
            "  none",
        });

    conf.defineOption<std::string>(
        "logging",
        "file",
        DefaultLogFile,
        AssignmentAcceptor(m_logFile),
        Comment{
            "When using type=file this is the output filename.",
        });
  }

  void
  PeerSelectionConfig::defineConfigOptions(
      ConfigDefinition& conf, const ConfigGenParameters& params)
  {
    (void)params;

    constexpr Default DefaultUniqueCIDR{32};
    conf.defineOption<int>(
        "paths",
        "unique-range-size",
        DefaultUniqueCIDR,
        ClientOnly,
        [=](int arg) {
          if (arg == 0)
          {
            m_UniqueHopsNetmaskSize = arg;
          }
          else if (arg > 32 or arg < 4)
          {
            throw std::invalid_argument{"[paths]:unique-range-size must be between 4 and 32"};
          }
          m_UniqueHopsNetmaskSize = arg;
        },
        Comment{
            "Netmask for router path selection; each router must be from a distinct IPv4 subnet",
            "of the given size.",
            "E.g. 16 ensures that all routers are using IPs from distinct /16 IP ranges."});

#ifdef WITH_GEOIP
    conf.defineOption<std::string>(
        "paths",
        "exclude-country",
        ClientOnly,
        MultiValue,
        [=](std::string arg) {
          m_ExcludeCountries.emplace(lowercase_ascii_string(std::move(arg)));
        },
        Comment{
            "Exclude a country given its 2 letter country code from being used in path builds.",
            "For example:",
            "    exclude-country=DE",
            "would avoid building paths through routers with IPs in Germany.",
            "This option can be specified multiple times to exclude multiple countries"});
#endif
  }

  bool
  PeerSelectionConfig::Acceptable(const std::set<RouterContact>& rcs) const
  {
    if (m_UniqueHopsNetmaskSize == 0)
      return true;
    const auto netmask = netmask_ipv6_bits(96 + m_UniqueHopsNetmaskSize);
    std::set<IPRange> seenRanges;
    for (const auto& hop : rcs)
    {
      for (const auto& addr : hop.addrs)
      {
        const auto network_addr = net::In6ToHUInt(addr.ip) & netmask;
        if (auto [it, inserted] = seenRanges.emplace(network_addr, netmask); not inserted)
        {
          return false;
        }
      }
    }
    return true;
  }

  std::unique_ptr<ConfigGenParameters>
  Config::MakeGenParams() const
  {
    return std::make_unique<ConfigGenParameters_impl>();
  }

  Config::Config(std::optional<fs::path> datadir)
      : m_DataDir{datadir ? std::move(*datadir) : fs::current_path()}
  {}

  constexpr auto GetOverridesDir = [](auto datadir) -> fs::path { return datadir / "conf.d"; };

  void
  Config::Save()
  {
    const auto overridesDir = GetOverridesDir(m_DataDir);
    if (not fs::exists(overridesDir))
      fs::create_directory(overridesDir);
    m_Parser.Save();
  }

  void
  Config::Override(std::string section, std::string key, std::string value)
  {
    m_Parser.AddOverride(GetOverridesDir(m_DataDir) / "overrides.ini", section, key, value);
  }

  void
  Config::LoadOverrides(ConfigDefinition& conf) const
  {
    ConfigParser parser;
    const auto overridesDir = GetOverridesDir(m_DataDir);
    if (fs::exists(overridesDir))
    {
      util::IterDir(overridesDir, [&](const fs::path& overrideFile) {
        if (overrideFile.extension() == ".ini")
        {
          ConfigParser parser;
          if (not parser.LoadFile(overrideFile))
            throw std::runtime_error{"cannot load '" + overrideFile.u8string() + "'"};

          parser.IterAll([&](std::string_view section, const SectionValues_t& values) {
            for (const auto& pair : values)
            {
              conf.addConfigValue(section, pair.first, pair.second);
            }
          });
        }
        return true;
      });
    }
  }

  void
  Config::AddDefault(std::string section, std::string key, std::string val)
  {
    m_Additional.emplace_back(std::array<std::string, 3>{section, key, val});
  }

  bool
  Config::LoadConfigData(std::string_view ini, std::optional<fs::path> filename, bool isRelay)
  {
    auto params = MakeGenParams();
    params->isRelay = isRelay;
    params->defaultDataDir = m_DataDir;
    ConfigDefinition conf{isRelay};
    addBackwardsCompatibleConfigOptions(conf);
    initializeConfig(conf, *params);

    for (const auto& item : m_Additional)
    {
      conf.addConfigValue(item[0], item[1], item[2]);
    }

    m_Parser.Clear();

    if (filename)
      m_Parser.Filename(*filename);
    else
      m_Parser.Filename(fs::path{});

    if (not m_Parser.LoadFromStr(ini))
      return false;

    m_Parser.IterAll([&](std::string_view section, const SectionValues_t& values) {
      for (const auto& pair : values)
      {
        conf.addConfigValue(section, pair.first, pair.second);
      }
    });

    LoadOverrides(conf);

    conf.process();

    return true;
  }

  bool
  Config::Load(std::optional<fs::path> fname, bool isRelay)
  {
    std::string ini;
    if (fname)
    {
      try
      {
        ini = util::slurp_file(*fname);
      }
      catch (const std::exception&)
      {
        return false;
      }
    }
    return LoadConfigData(ini, fname, isRelay);
  }

  bool
  Config::LoadString(std::string_view ini, bool isRelay)
  {
    return LoadConfigData(ini, std::nullopt, isRelay);
  }

  bool
  Config::LoadDefault(bool isRelay)
  {
    return LoadString("", isRelay);
  }

  void
  Config::initializeConfig(ConfigDefinition& conf, const ConfigGenParameters& params)
  {
    router.defineConfigOptions(conf, params);
    network.defineConfigOptions(conf, params);
    paths.defineConfigOptions(conf, params);
    connect.defineConfigOptions(conf, params);
    dns.defineConfigOptions(conf, params);
    links.defineConfigOptions(conf, params);
    api.defineConfigOptions(conf, params);
    lokid.defineConfigOptions(conf, params);
    bootstrap.defineConfigOptions(conf, params);
    logging.defineConfigOptions(conf, params);
  }

  void
  Config::addBackwardsCompatibleConfigOptions(ConfigDefinition& conf)
  {
    // These config sections don't exist anymore:

    conf.defineOption<std::string>("system", "user", Deprecated);
    conf.defineOption<std::string>("system", "group", Deprecated);
    conf.defineOption<std::string>("system", "pidfile", Deprecated);

    conf.defineOption<std::string>("netdb", "dir", Deprecated);

    conf.defineOption<std::string>("metrics", "json-metrics-path", Deprecated);
  }

  void
  ensureConfig(fs::path dataDir, fs::path confFile, bool overwrite, bool asRouter)
  {
    // fail to overwrite if not instructed to do so
    if (fs::exists(confFile) && !overwrite)
    {
      LogDebug("Not creating config file; it already exists.");
      return;
    }

    const auto parent = confFile.parent_path();

    // create parent dir if it doesn't exist
    if ((not parent.empty()) and (not fs::exists(parent)))
    {
      fs::create_directory(parent);
    }

    llarp::LogInfo(
        "Attempting to create config file for ",
        (asRouter ? "router" : "client"),
        " at ",
        confFile);

    llarp::Config config{dataDir};
    std::string confStr;
    if (asRouter)
      confStr = config.generateBaseRouterConfig();
    else
      confStr = config.generateBaseClientConfig();

    // open a filestream
    try
    {
      util::dump_file(confFile, confStr);
    }
    catch (const std::exception& e)
    {
      throw std::runtime_error{
          fmt::format("Failed to write config data to {}: {}", confFile, e.what())};
    }

    llarp::LogInfo("Generated new config ", confFile);
  }

  void
  generateCommonConfigComments(ConfigDefinition& def)
  {
    // router
    def.addSectionComments(
        "router",
        {
            "Configuration for routing activity.",
        });

    // logging
    def.addSectionComments(
        "logging",
        {
            "logging settings",
        });

    // api
    def.addSectionComments(
        "api",
        {
            "JSON API settings",
        });

    // dns
    def.addSectionComments(
        "dns",
        {
            "DNS configuration",
        });

    // bootstrap
    def.addSectionComments(
        "bootstrap",
        {
            "Configure nodes that will bootstrap us onto the network",
        });

    // network
    def.addSectionComments(
        "network",
        {
            "Network settings",
        });
  }

  std::string
  Config::generateBaseClientConfig()
  {
    auto params = MakeGenParams();
    params->isRelay = false;
    params->defaultDataDir = m_DataDir;

    llarp::ConfigDefinition def{false};
    initializeConfig(def, *params);
    generateCommonConfigComments(def);
    def.addSectionComments(
        "paths",
        {
            "path selection algorithm options",
        });

    def.addSectionComments(
        "network",
        {
            "Snapp settings",
        });

    return def.generateINIConfig(true);
  }

  std::string
  Config::generateBaseRouterConfig()
  {
    auto params = MakeGenParams();
    params->isRelay = true;
    params->defaultDataDir = m_DataDir;

    llarp::ConfigDefinition def{true};
    initializeConfig(def, *params);
    generateCommonConfigComments(def);

    // oxend
    def.addSectionComments(
        "lokid",
        {
            "Settings for communicating with oxend",
        });

    return def.generateINIConfig(true);
  }

  std::shared_ptr<Config>
  Config::EmbeddedConfig()
  {
    auto config = std::make_shared<Config>();
    config->Load();
    config->logging.m_logLevel = log::Level::off;
    config->api.m_enableRPCServer = false;
    config->network.m_endpointType = "null";
    config->network.m_saveProfiles = false;
    config->bootstrap.files.clear();
    return config;
  }

}  // namespace llarp