IP address support for tls-rust

[gilescope]

At the moment when using the tls-rust back end it's checking that every host is a valid DNS, but IP addresses are not valid DNS names and thus it fails here:

https://github.com/sbstp/attohttpc/blob/147f7aef2fba7440e9c835feacfdffac4e418697/src/tls/rustls_impl.rs#L63

Presumably we need to skip dns resolution in this case?

[gilescope]

This is an interesting divergence from reqwest. When they have .danger_accept_invalid_certs(true) set, they manage (somehow?) to be able to work with an IP address.

[adamreichold]

Are you sure this works with reqwest?

https://github.com/seanmonstar/reqwest/blob/c666b293a139d1d9d681115d1f5090622a240835/src/connect.rs#L280

would suggest the same issue as described here?

[adamreichold]

Using the current master branch of reqwest and the diff

diff --git a/examples/blocking.rs b/examples/blocking.rs
index a2b81c5..a1b25c6 100644
--- a/examples/blocking.rs
+++ b/examples/blocking.rs
@@ -6,7 +6,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
 
     println!("GET https://www.rust-lang.org");
 
-    let mut res = reqwest::blocking::get("https://www.rust-lang.org/")?;
+    let mut res = reqwest::blocking::ClientBuilder::new().danger_accept_invalid_certs(true).build()?.get("https://140.82.121.3").send()?;
 
     println!("Status: {}", res.status());
     println!("Headers:\n{:?}", res.headers());

and running

cargo run --no-default-features --features "blocking rustls-tls" --example blocking

yields

Error: reqwest::Error { kind: Request, url: Url { scheme: "https", username: "", password: None, host: Some(Ipv4(140.82.121.3)), port: None, path: "/", query: None, fragment: None }, source: hyper::Error(Connect, Custom { kind: Other, error: "invalid dnsname" }) }

indeed. (The IP address is what github.com resolves to here.)

[adamreichold]

The rustls documentation also suggests that a DNSNameRef is required, e.g. https://docs.rs/rustls/0.19.0/rustls/struct.ClientSession.html