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punch-client-forwarder.zig
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punch-client-forwarder.zig
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const std = @import("std");
const mem = std.mem;
const os = std.os;
const net = std.net;
const logging = @import("./logging.zig");
const common = @import("./common.zig");
const netext = @import("./netext.zig");
const timing = @import("./timing.zig");
const eventing = @import("./eventing.zig").default;
const punch = @import("./punch.zig");
const proxy = @import("./proxy.zig");
const log = logging.log;
const fd_t = os.fd_t;
const Address = net.Address;
const delaySeconds = common.delaySeconds;
const Timestamp = timing.Timestamp;
const Timer = timing.Timer;
const EventFlags = eventing.EventFlags;
const PunchRecvState = punch.util.PunchRecvState;
const Proxy = proxy.Proxy;
const HostAndProxy = proxy.HostAndProxy;
const Eventer = eventing.EventerTemplate(.{
.Data = struct {
punchFd: fd_t,
rawFd: fd_t,
punchRecvState: *PunchRecvState,
gotCloseTunnel: *bool,
},
.CallbackError = error {
PunchSocketDisconnect,
RawSocketDisconnect,
},
.CallbackData = struct {
fd: fd_t,
},
});
const global = struct {
var ignoreSigaction : os.Sigaction = undefined;
var arena = std.heap.ArenaAllocator.init(std.heap.page_allocator);
var rawForwardAddr : Address = undefined;
var buffer : [8192]u8 = undefined;
};
fn setupSignals() void {
global.ignoreSigaction.handler.sigaction = os.SIG.IGN;
std.mem.set(u32, &global.ignoreSigaction.mask, 0);
global.ignoreSigaction.flags = 0;
os.sigaction(os.SIG.PIPE, &global.ignoreSigaction, null);
}
fn usage() void {
std.debug.warn("Usage: punch-client-forwarder PUNCH_SERVER PUNCH_PORT FORWARD_HOST FORWARD_PORT\n", .{});
std.debug.warn("\n", .{});
std.debug.warn("enable proxy with http://PROXY_HOST:PROXY_PORT/PUNCH_SERVER\n", .{});
}
pub fn main() anyerror!u8 {
setupSignals();
var args = try std.process.argsAlloc(&global.arena.allocator);
if (args.len <= 1) {
usage();
return 1;
}
args = args[1..];
if (args.len != 4) {
usage();
return 1;
}
const punchConnectSpec = args[0];
const punchPort = common.parsePort(args[1]) catch return 1;
const rawForwardString = args[2];
const rawForwardPort = common.parsePort(args[3]) catch return 1;
const punchHostAndProxy = proxy.parseProxy(punchConnectSpec) catch |e| {
log("Error: invalid connect specifier '{s}': {}", .{punchConnectSpec, e});
return 1;
};
global.rawForwardAddr = common.parseIp4(rawForwardString, rawForwardPort) catch return 1;
var connectThrottler = makeThrottler("connect throttler: ");
while (true) {
connectThrottler.throttle();
switch (sequenceConnectToPunchClient(&punchHostAndProxy, punchPort)) {
error.PunchSocketDisconnect => {},
}
}
}
fn makeThrottler(logPrefix: []const u8) timing.Throttler {
return (timing.makeThrottler {
.logPrefix = logPrefix,
.desiredSleepMillis = 15000,
.slowRateMillis = 500,
}).create();
}
fn sequenceConnectToPunchClient(punchHostAndProxy: *const HostAndProxy, punchPort: u16) error {
PunchSocketDisconnect,
} {
log("connecting to punch server {}{s}:{}...", .{punchHostAndProxy.proxy, punchHostAndProxy.host, punchPort});
const punchFd = netext.proxyConnect(&punchHostAndProxy.proxy, punchHostAndProxy.host, punchPort) catch |e| switch (e) {
error.Retry => return error.PunchSocketDisconnect,
};
defer common.shutdownclose(punchFd);
log("connected to punch server", .{});
punch.util.doHandshake(punchFd, .forwarder, 10000) catch |e| switch (e) {
error.PunchSocketDisconnect
,error.BadPunchHandshake
=> return error.PunchSocketDisconnect,
};
var heartbeatTimer = Timer.init(15000);
var waitOpenTunnelThrottler = makeThrottler("wait for OpenTunnel: ");
while (true) {
waitOpenTunnelThrottler.throttle();
log("waiting for OpenTunnel...", .{});
waitForOpenTunnelMessage(punchFd, &heartbeatTimer) catch |e| switch (e) {
error.PunchSocketDisconnect => return error.PunchSocketDisconnect,
};
var punchRecvState : PunchRecvState = PunchRecvState.Initial;
var gotCloseTunnel = false;
switch (sequenceConnectRawClient(punchFd, &heartbeatTimer, &punchRecvState, &gotCloseTunnel)) {
error.PunchSocketDisconnect => return error.PunchSocketDisconnect,
error.RawSocketDisconnect => {
try punch.util.closeTunnel(punchFd, &punchRecvState, &gotCloseTunnel, &global.buffer);
continue;
},
}
}
}
fn sequenceConnectRawClient(punchFd: fd_t, heartbeatTimer: *Timer, punchRecvState: *PunchRecvState, gotCloseTunnel: *bool) error {
PunchSocketDisconnect,
RawSocketDisconnect,
} {
const rawFd = netext.socket(global.rawForwardAddr.any.family, os.SOCK.STREAM , os.IPPROTO.TCP) catch |e| switch (e) {
error.Retry => return error.RawSocketDisconnect,
};
defer os.close(rawFd);
log("s={} connecting raw to {}", .{rawFd, global.rawForwardAddr});
netext.connect(rawFd, &global.rawForwardAddr) catch |e| switch (e) {
error.Retry => return error.RawSocketDisconnect,
};
defer common.shutdown(rawFd) catch |e| {
log("WARNING: shutdown raw s={} failed with {}", .{rawFd, e});
};
log("s={} raw side connected", .{rawFd});
var eventingThrottler = makeThrottler("eventing throttler: ");
while (true) {
eventingThrottler.throttle();
switch (sequenceForwardingLoop(punchFd, heartbeatTimer, punchRecvState, gotCloseTunnel, rawFd)) {
error.EpollError => continue,
error.PunchSocketDisconnect => return error.PunchSocketDisconnect,
error.RawSocketDisconnect => return error.RawSocketDisconnect,
}
}
}
fn waitForOpenTunnelMessage(punchFd: fd_t, heartbeatTimer: *Timer) !void {
while (true) {
const sleepMillis = punch.util.serviceHeartbeat(punchFd, heartbeatTimer, false) catch |e| switch (e) {
error.PunchSocketDisconnect => return error.PunchSocketDisconnect,
};
var buf: [1]u8 = undefined;
const gotMessage = netext.recvfullTimeout(punchFd, &buf, sleepMillis) catch |e| switch (e) {
error.Disconnected => return error.PunchSocketDisconnect,
error.Retry => {
// we can do this because we are only receiving 1-byte
delaySeconds(1, "before calling recv again...");
continue;
},
};
if (gotMessage) {
if (buf[0] == punch.proto.TwoWayMessage.Heartbeat) {
//log("[DEBUG] got heartbeat", .{});
} else if(buf[0] == punch.proto.InitiatorMessage.OpenTunnel) {
log("got OpenTunnel message", .{});
return;
} else {
log("got unexpected punch message {}, will disconnect", .{buf[0]});
return error.PunchSocketDisconnect;
}
}
}
}
// Note: !noreturn would be better in this case (see https://github.com/ziglang/zig/issues/3461)
fn sequenceForwardingLoop(punchFd: fd_t, heartbeatTimer: *Timer, punchRecvState: *PunchRecvState,
gotCloseTunnel: *bool, rawFd: fd_t) error {
EpollError,
PunchSocketDisconnect,
RawSocketDisconnect,
} {
var eventer = common.eventerInit(Eventer, Eventer.Data {
.punchFd = punchFd,
.rawFd = rawFd,
.punchRecvState = punchRecvState,
.gotCloseTunnel = gotCloseTunnel,
}) catch |e| switch (e) {
error.Retry => return error.EpollError,
};
defer eventer.deinit();
var punchCallback = Eventer.Callback {
.func = onPunchData,
.data = .{.fd = punchFd},
};
common.eventerAdd(Eventer, &eventer, punchFd, EventFlags.read, &punchCallback) catch |e| switch (e) {
error.Retry => return error.EpollError,
};
defer eventer.remove(punchFd);
var rawCallback = Eventer.Callback {
.func = onRawData,
.data = .{.fd = rawFd},
};
common.eventerAdd(Eventer, &eventer, rawFd, EventFlags.read, &rawCallback) catch |e| switch (e) {
error.Retry => return error.EpollError,
};
defer eventer.remove(rawFd);
while (true) {
const sleepMillis = punch.util.serviceHeartbeat(punchFd, heartbeatTimer, false) catch |e| switch (e) {
error.PunchSocketDisconnect => return error.PunchSocketDisconnect,
};
//log("[DEBUG] waiting for events (sleep {} ms)...", .{sleepMillis});
_ = eventer.handleEvents(sleepMillis) catch |e| switch (e) {
error.PunchSocketDisconnect => return error.PunchSocketDisconnect,
error.RawSocketDisconnect => return error.RawSocketDisconnect,
};
}
}
fn onRawData(eventer: *Eventer, callback: *Eventer.Callback) Eventer.CallbackError!void {
std.debug.assert(callback.data.fd == eventer.data.rawFd);
punch.util.forwardRawToPunch(callback.data.fd, eventer.data.punchFd, &global.buffer) catch |e| switch (e) {
error.RawSocketDisconnect => return error.RawSocketDisconnect,
error.PunchSocketDisconnect => return error.PunchSocketDisconnect,
};
}
fn onPunchData(eventer: *Eventer, callback: *Eventer.Callback) Eventer.CallbackError!void {
const len = netext.read(callback.data.fd, &global.buffer) catch |e| switch (e) {
error.Retry => {
delaySeconds(1, "before trying to read punch socket again...");
return;
},
error.Disconnected => return error.PunchSocketDisconnect,
};
if (len == 0) {
log("punch socket disconnected (read returned 0)", .{});
return error.PunchSocketDisconnect;
}
var data = global.buffer[0..len];
while (data.len > 0) {
const action = punch.util.parsePunchToNextAction(eventer.data.punchRecvState, &data) catch |e| switch (e) {
error.InvalidPunchMessage => {
log("received unexpected punch message {}", .{data[0]});
// socket will be shutdown in a defer
return error.PunchSocketDisconnect;
},
};
switch (action) {
.None => {
std.debug.assert(data.len == 0);
break;
},
.OpenTunnel => {
log("WARNING: received OpenTunnel message when a tunnel is already open", .{});
// socket will be shutdown in a defer
return error.PunchSocketDisconnect;
},
.CloseTunnel => {
log("received CloseTunnel message", .{});
eventer.data.gotCloseTunnel.* = true;
return error.RawSocketDisconnect;
},
.ForwardData => |forwardAction| {
//log("[VERBOSE] forwarding {} bytes to raw socket...", .{forwardAction.data.len});
netext.send(eventer.data.rawFd, forwardAction.data, 0) catch |e| switch (e) {
error.Disconnected, error.Retry => {
log("s={} send failed on raw socket", .{eventer.data.rawFd});
return error.RawSocketDisconnect;
},
};
},
}
}
}