### SIP REGISTER Request Example (RFC3665)

Source: https://github.com/televiska/rsip/blob/master/README.md

An example of a raw SIP REGISTER request message, as specified in section 2.1 of RFC3665, demonstrating the structure and required headers for a basic registration.

```SIP
REGISTER sips:ss2.biloxi.example.com SIP/2.0
Via: SIP/2.0/TLS client.biloxi.example.com:5061;branch=z9hG4bKnashds7
Max-Forwards: 70
From: Bob <sips:bob@biloxi.example.com>;tag=a73kszlfl
To: Bob <sips:bob@biloxi.example.com>
Call-ID: 1j9FpLxk3uxtm8tn@biloxi.example.com
CSeq: 1 REGISTER
Contact: <sips:bob@client.biloxi.example.com>
Content-Length: 0
```

--------------------------------

### SIP 401 Unauthorized Response Example

Source: https://github.com/televiska/rsip/blob/master/README.md

An example of a raw SIP 401 Unauthorized response message, demonstrating the structure and headers, including the `WWW-Authenticate` header for Digest authentication.

```SIP
SIP/2.0 401 Unauthorized
Via: SIP/2.0/TLS client.biloxi.example.com:5061;branch=z9hG4bKnashds7
 ;received=192.0.2.201
From: Bob <sips:bob@biloxi.example.com>;tag=a73kszlfl
To: Bob <sips:bob@biloxi.example.com>;tag=1410948204
Call-ID: 1j9FpLxk3uxtm8tn@biloxi.example.com
CSeq: 1 REGISTER
WWW-Authenticate: Digest realm="atlanta.example.com", qop="auth",
 nonce="ea9c8e88df84f1cec4341ae6cbe5a359",
 opaque="", stale=FALSE, algorithm=MD5
Content-Length: 0
```

--------------------------------

### Generate SIP REGISTER Request in Rust with rsip

Source: https://github.com/televiska/rsip/blob/master/README.md

Rust code using the `rsip` library to programmatically construct a SIP REGISTER request. This function builds the message headers and URI, mirroring the example from RFC3665, and returns a `rsip::SipMessage`.

```Rust
fn generate_register_request() -> rsip::SipMessage {
    let mut headers: rsip::Headers = Default::default();

    let base_uri = rsip::Uri {
        scheme: Some(rsip::Scheme::Sips),
        auth: Some(("bob", Option::<String>::None).into()),
        host_with_port: rsip::Domain::from("biloxi.example.com").into(),
        ..Default::default()
    };

    headers.push(
        rsip::typed::Via {
            version: rsip::Version::V2,
            transport: rsip::Transport::Tls,
            uri: rsip::Uri {
                host_with_port: (rsip::Domain::from("client.biloxi.example.com"), 5060).into(),
                ..Default::default()
            },
            params: vec![rsip::Param::Branch(rsip::param::Branch::new(
                "z9hG4bKnashds7",
            ))],
        }
        .into(),
    );
    headers.push(rsip::headers::MaxForwards::default().into());
    headers.push(
        rsip::typed::From {
            display_name: Some("Bob".into()),
            uri: base_uri.clone(),
            params: vec![rsip::Param::Tag(rsip::param::Tag::new("a73kszlfl"))],
        }
        .into(),
    );
    headers.push(
        rsip::typed::To {
            display_name: Some("Bob".into()),
            uri: base_uri.clone(),
            params: Default::default(),
        }
        .into(),
    );
    headers.push(rsip::headers::CallId::default().into());
    headers.push(
        rsip::typed::CSeq {
            seq: 1,
            method: rsip::Method::Register,
        }
        .into(),
    );
    headers.push(
        rsip::typed::Contact {
            display_name: None,
            uri: base_uri,
            params: Default::default(),
        }
        .into(),
    );
    headers.push(rsip::headers::ContentLength::default().into());

    rsip::Request {
        method: rsip::Method::Register,
        uri: rsip::Uri {
            scheme: Some(rsip::Scheme::Sips),
            host_with_port: rsip::Domain::from("ss2.biloxi.example.com").into(),
            ..Default::default()
        },
        version: rsip::Version::V2,
        headers: headers,
        body: Default::default(),
    }
    .into()
}
```

--------------------------------

### Generate SIP 401 Unauthorized Response in Rust with rsip

Source: https://github.com/televiska/rsip/blob/master/README.md

Rust code using the `rsip` library to generate a SIP 401 Unauthorized response. This function takes an incoming `rsip::Request` and constructs a corresponding 401 response, including essential headers like `Via`, `From`, `To` (with a new tag), `Call-ID`, `CSeq`, `Content-Length`, `Server`, and a `WWW-Authenticate` header with Digest authentication parameters.

```Rust
pub fn create_unauthorized_from(request: rsip::Request) -> Result<rsip::SipMessage, crate::Error> {
    //imports helpful header traits
    use rsip::prelude::*;

    let mut headers: rsip::Headers = Default::default();
    headers.push(request.via_header()?.clone().into());
    headers.push(request.from_header()?.clone().into());
    let mut to = request.to_header()?.typed()?;
    to.with_tag("1410948204".into());
    headers.push(to.into());
    headers.push(request.call_id_header()?.clone().into());
    headers.push(request.cseq_header()?.clone().into());
    headers.push(rsip::Header::ContentLength(Default::default()));
    headers.push(rsip::Header::Server(Default::default()));

    headers.push(
        rsip::typed::WwwAuthenticate {
            realm: "atlanta.example.com".into(),
            nonce: "ea9c8e88df84f1cec4341ae6cbe5a359".into(),
            algorithm: Some(rsip::headers::auth::Algorithm::Md5),
            qop: Some(rsip::headers::auth::Qop::Auth),
            stale: Some("FALSE".into()),
            opaque: Some("".into()),
            ..Default::default()
        }
        .into(),
    );

    Ok(rsip::Response {
        status_code: 401.into(),
        headers,
        version: rsip::Version::V2,
        body: Default::default()
    }
    .into())
}
```

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