From 1034b1aa5c393de4296a2edd73d7b546a323f7f3 Mon Sep 17 00:00:00 2001
From: Philippe Pittoli <karchnu@karchnu.fr>
Date: Wed, 11 Jan 2023 16:34:43 +0100
Subject: [PATCH] TCPd: preliminary work. Lacks actual TCP connection but
 switching is okay.

---
 zig-impl/src/tcpd.zig | 147 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 147 insertions(+)
 create mode 100644 zig-impl/src/tcpd.zig

diff --git a/zig-impl/src/tcpd.zig b/zig-impl/src/tcpd.zig
new file mode 100644
index 0000000..791ad7d
--- /dev/null
+++ b/zig-impl/src/tcpd.zig
@@ -0,0 +1,147 @@
+const std = @import("std");
+const hexdump = @import("./hexdump.zig");
+const net = std.net;
+const fmt = std.fmt;
+const os = std.os;
+
+const ipc = @import("./main.zig");
+const Message = ipc.Message;
+
+// Import send_fd this way in order to produce docs for exchange-fd functions.
+const exchange_fd = @import("./exchange-fd.zig");
+const send_fd = exchange_fd.send_fd;
+
+const builtin = @import("builtin");
+const native_os = builtin.target.os.tag;
+const print = std.debug.print;
+const testing = std.testing;
+const print_eq = @import("./util.zig").print_eq;
+const URI = @import("./util.zig").URI;
+
+fn create_service() !void {
+    const config = .{.safety = true};
+    var gpa = std.heap.GeneralPurposeAllocator(config){};
+    defer _ = gpa.deinit();
+    const allocator = gpa.allocator();
+
+    var ctx = try ipc.Context.init(allocator);
+    defer ctx.deinit(); // There. Can't leak. Isn't Zig wonderful?
+
+    // SERVER SIDE: creating a service.
+    _ = try ctx.server_init("tcp");
+
+    // signal handler, to quit when asked
+    const S = struct {
+        var should_quit: bool = false;
+
+        fn handler(sig: i32, info: *const os.siginfo_t, _: ?*const anyopaque) callconv(.C) void {
+            print ("A signal has been received: {}\n", .{sig});
+            // Check that we received the correct signal.
+            switch (native_os) {
+                .netbsd => {
+                    if (sig != os.SIG.HUP or sig != info.info.signo)
+                        return;
+                },
+                else => {
+                    if (sig != os.SIG.HUP and sig != info.signo)
+                        return;
+                },
+            }
+            should_quit = true;
+        }
+    };
+
+    var sa = os.Sigaction{
+        .handler = .{ .sigaction = &S.handler },
+        .mask = os.empty_sigset, // Do not mask any signal.
+        .flags = os.SA.SIGINFO,
+    };
+
+    // Quit on SIGHUP (kill -1).
+    try os.sigaction(os.SIG.HUP, &sa, null);
+
+    var some_event: ipc.Event = undefined;
+    ctx.timer = 1000; // 1 second
+    var count: u32 = 0;
+    while(! S.should_quit) {
+        some_event = try ctx.wait_event();
+        switch (some_event.t) {
+            .TIMER => {
+                print("\rTimer! ({})", .{count});
+                count += 1;
+            },
+
+            .CONNECTION => {
+                print("New connection: {} so far!\n", .{ctx.pollfd.items.len});
+            },
+
+            .DISCONNECTION => {
+                print("User {} disconnected, {} remainaing.\n"
+                    , .{some_event.origin, ctx.pollfd.items.len});
+            },
+
+            .EXTERNAL => {
+                print("Message received from a non IPC socket.\n", .{});
+                print("NOT IMPLEMENTED, YET. It's a suicide, then.\n", .{});
+                break;
+            },
+
+            .SWITCH_RX => {
+                print("Message has been received (SWITCH).\n", .{});
+            },
+
+            .SWITCH_TX => {
+                print("Message has been sent (SWITCH).\n", .{});
+            },
+
+            .MESSAGE => {
+                print("Client asking for a service through TCPd.\n", .{});
+                if (some_event.m) |m| {
+                    print("{}\n", .{m});
+                    defer m.deinit(); // Do not forget to free the message payload.
+
+                    print ("URI to work with is {s}\n", .{m.payload});
+                    var uri = URI.read(m.payload);
+                    print ("proto [{s}] address [{s}] path [{s}]\n"
+                        , .{uri.protocol, uri.address, uri.path});
+
+                    // TODO FIXME: CURRENTLY ONLY CONNECT TO LOCAL UNIX SERVICE
+                    // TODO: TCP!!
+                    var servicefd = try ctx.connect_service (uri.path);
+
+                    // Connection is established, inform IPCd.
+                    var response = try Message.init(some_event.origin, allocator, "ok");
+                    defer response.deinit();
+                    try ctx.write(response);
+
+                    // Let's switch the connections!
+                    try ctx.add_switch(some_event.origin, servicefd);
+                    // TODO: for real TCP code, invoke: ctx.set_switch_callbacks ();
+                }
+                else {
+                    // TCPd was contacted without providing a message, nothing to do.
+                    var response = try Message.init(some_event.origin, allocator, "no");
+                    defer response.deinit();
+                    try ctx.write(response);
+                    try ctx.close(some_event.index);
+                }
+            },
+
+            .TX => {
+                print("Message sent.\n", .{});
+            },
+
+            .ERROR => {
+                print("A problem occured, event: {}, let's suicide\n", .{some_event});
+                break;
+            },
+        }
+    }
+
+    print("Goodbye\n", .{});
+}
+
+pub fn main() !u8 {
+    try create_service();
+    return 0;
+}