iroh-relay does not work behind nginx proxy

[link2xt]

Merged #434 does not actually work with CI. Current Rust CI fails with:

2024-10-30T17:35:07.513075Z ERROR iroh_net::relay::client: expected status 101 SWITCHING_PROTOCOLS, got: 400 Bad Request
2024-10-30T17:35:07.727201Z ERROR iroh_net::relay::client: expected status 101 SWITCHING_PROTOCOLS, got: 400 Bad Request
2024-10-30T17:35:07.860342Z ERROR iroh_net::relay::client: expected status 101 SWITCHING_PROTOCOLS, got: 400 Bad Request
2024-10-30T17:35:08.072525Z ERROR iroh_net::relay::client: expected status 101 SWITCHING_PROTOCOLS, got: 400 Bad Request
2024-10-30T17:35:08.209491Z ERROR iroh_net::relay::client: expected status 101 SWITCHING_PROTOCOLS, got: 400 Bad Request
2024-10-30T17:35:08.420977Z ERROR iroh_net::relay::client: expected status 101 SWITCHING_PROTOCOLS, got: 400 Bad Request

Probably something like websocket support is missing.

[link2xt]

iroh relay uses Upgrade header with values "iroh derp http" and "websocket". At least "Upgrade" header should be passed through.

[link2xt]

I added Environment="RUST_LOG=debug" to /etc/systemd/system/iroh-relay.service to make it log all HTTP requests. Looks like nginx does not pass the requests through and responds with 400 Bad Request.

With some debug logging from nginx, looks like it is unhappy with "Upgrade: iroh derp http" header:

Oct 30 23:47:36 c2-new nginx[1316977]: 2024/10/30 23:47:36 [debug] 1316977#1316977: *162 http process request line
Oct 30 23:47:36 c2-new nginx[1316977]: 2024/10/30 23:47:36 [debug] 1316977#1316977: *162 http request line: "GET /relay HTTP/1.1"
Oct 30 23:47:36 c2-new nginx[1316977]: 2024/10/30 23:47:36 [debug] 1316977#1316977: *162 http uri: "/relay"
Oct 30 23:47:36 c2-new nginx[1316977]: 2024/10/30 23:47:36 [debug] 1316977#1316977: *162 http args: ""
Oct 30 23:47:36 c2-new nginx[1316977]: 2024/10/30 23:47:36 [debug] 1316977#1316977: *162 http exten: ""
Oct 30 23:47:36 c2-new nginx[1316977]: 2024/10/30 23:47:36 [debug] 1316977#1316977: *162 posix_memalign: 000055BC6A4E5F90:4096 @16
Oct 30 23:47:36 c2-new nginx[1316977]: 2024/10/30 23:47:36 [debug] 1316977#1316977: *162 http process request header line
Oct 30 23:47:36 c2-new nginx[1316977]: 2024/10/30 23:47:36 [debug] 1316977#1316977: *162 http header: "upgrade: iroh derp http"
Oct 30 23:47:36 c2-new nginx[1316977]: 2024/10/30 23:47:36 [debug] 1316977#1316977: *162 http header done
Oct 30 23:47:36 c2-new nginx[1316977]: c2-new nginx: 127.0.0.1 - - [30/Oct/2024:23:47:36 +0000] "GET /relay HTTP/1.1" 400 150 "-" "-"

[link2xt]

Enabled some more debug logging in nginx:

Oct 30 23:55:42 c2-new nginx[1317239]: 2024/10/30 23:55:42 [info] 1317239#1317239: *210 client sent HTTP/1.1 request without "Host" header while reading client request headers, client: 127.0.0.1, server: _, request: "GET /relay HTTP/1.1"
Oct 30 23:55:42 c2-new nginx[1317239]: c2-new nginx: 127.0.0.1 - - [30/Oct/2024:23:55:42 +0000] "GET /relay HTTP/1.1" 400 150 "-" "-"

Seems iroh client does not send the Host header.