grpc 0.9.0

/*
 *
 * Copyright 2026 gRPC authors.
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 * furnished to do so, subject to the following conditions:
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//! Authentication and security credentials (e.g. TLS and OAuth2).
//!
//! This module provides traits and types for handling credentials in gRPC,
//! including channel credentials (for securing connections) and call
//! credentials (for authenticating individual RPCs).
//!
//! # Key Concepts
//!
//! - **[`ChannelCredentials`]:** Trait for client-side transport security
//!   (e.g., TLS). May also include [`CallCredentials`] by using
//!   [`CompositeChannelCredentials`].
//! - **[`ServerCredentials`]:** Trait for server-side transport security.

pub mod call;
pub(crate) mod client;
pub(crate) mod dyn_wrapper;
mod local;
#[cfg(feature = "tls-rustls")]
pub mod rustls;
pub(crate) mod server;

use std::sync::Arc;

pub use client::CompositeChannelCredentials;
pub use local::LocalChannelCredentials;
pub use local::LocalServerCredentials;

use crate::credentials::call::CallCredentials;
use crate::credentials::client::ClientConnectionSecurityContext;
use crate::credentials::client::ClientHandshakeInfo;
use crate::credentials::client::HandshakeOutput;
use crate::credentials::common::Authority;
use crate::private;
use crate::rt::GrpcEndpoint;
use crate::rt::GrpcRuntime;

/// Client-side trait for all live gRPC wire protocols and supported transport
/// security protocols (e.g., TLS, ALTS).
///
/// Also includes the ability to attach [`CallCredentials`] when used with the
/// [`CompositeChannelCredentials`].
#[trait_variant::make(Send)]
pub trait ChannelCredentials: Sync + 'static {
    #[doc(hidden)]
    type ContextType: ClientConnectionSecurityContext;
    #[doc(hidden)]
    type Output<I>;

    /// Provides the ProtocolInfo of these credentials.
    fn info(&self) -> &ProtocolInfo;

    /// Returns call credentials to be used for all RPCs made on a connection.
    #[doc(hidden)]
    fn get_call_credentials(&self, token: private::Internal) -> Option<&Arc<dyn CallCredentials>>;

    /// Performs the client-side authentication handshake on a raw endpoint.
    ///
    /// This method wraps the provided `source` endpoint with the security protocol
    /// (e.g., TLS) and returns the authenticated endpoint along with its
    /// security details.
    ///
    /// # Arguments
    ///
    /// * `authority` - The `:authority` header value to be used when creating
    ///   new streams.
    ///   **Important:** Implementations must use this value as the server name
    ///   (e.g., for SNI) during the handshake.
    /// * `source` - The raw connection handle.
    /// * `info` - Additional context passed from the resolver or load balancer.
    #[doc(hidden)]
    async fn connect<Input: GrpcEndpoint>(
        &self,
        authority: &Authority,
        source: Input,
        info: &ClientHandshakeInfo,
        runtime: &GrpcRuntime,
        token: private::Internal,
    ) -> Result<HandshakeOutput<Self::Output<Input>, Self::ContextType>, String>;
}

/// Server-side trait for all live gRPC wire protocols and supported
/// transport security protocols (e.g., TLS, ALTS).
#[trait_variant::make(Send)]
pub trait ServerCredentials: Sync + 'static {
    #[doc(hidden)]
    type Output<I>;

    /// Provides the ProtocolInfo of these credentials.
    fn info(&self) -> &ProtocolInfo;

    /// Performs the server-side authentication handshake.
    ///
    /// This method wraps the incoming raw `source` connection with the configured
    /// security protocol (e.g., TLS).
    #[doc(hidden)]
    async fn accept<Input: GrpcEndpoint>(
        &self,
        source: Input,
        runtime: GrpcRuntime,
        token: private::Internal,
    ) -> Result<server::HandshakeOutput<Self::Output<Input>>, String>;
}

/// Defines the level of protection provided by an established connection.
#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
#[non_exhaustive]
pub enum SecurityLevel {
    /// The connection is insecure; no protection is applied.
    NoSecurity,
    /// The connection guarantees data integrity (tamper-proofing) but not
    /// privacy.
    ///
    /// Payloads are visible to observers but cannot be modified without
    /// detection.
    IntegrityOnly,
    /// The connection guarantees both privacy (confidentiality) and data
    /// integrity.
    ///
    /// This is the standard level for secure transports like TLS.
    PrivacyAndIntegrity,
}

pub(crate) mod common {
    /// Represents the value passed as the `:authority` pseudo-header, typically
    /// in the form `host:port`.
    #[derive(Clone, PartialEq, Debug)]
    pub struct Authority {
        host: String,
        port: Option<u16>,
    }

    impl Authority {
        pub fn new(host: impl Into<String>, port: Option<u16>) -> Self {
            Self {
                host: host.into(),
                port,
            }
        }

        pub fn host(&self) -> &str {
            &self.host
        }

        pub fn port(&self) -> Option<u16> {
            self.port
        }

        pub fn host_port_string(&self) -> String {
            let host_str = &self.host;
            match self.port() {
                None => host_str.to_string(),
                // Add [] for IPv6 addresses.
                Some(port) if host_str.contains(':') => {
                    format!("[{}]:{}", host_str, port)
                }
                Some(port) => format!("{}:{}", host_str, port),
            }
        }
    }
}

/// Contains information about a [`ChannelCredentials`] or
/// [`ServerCredentials`].
pub struct ProtocolInfo {
    security_protocol: &'static str,
}

impl ProtocolInfo {
    pub(crate) const fn new(security_protocol: &'static str) -> Self {
        Self { security_protocol }
    }

    /// Returns the security protocol name currently in use, e.g. "tls".
    pub fn security_protocol(&self) -> &'static str {
        self.security_protocol
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn authority_host_port_str() {
        let authority = Authority::new("localhost", None);
        assert_eq!(&authority.host_port_string(), "localhost");

        let authority = Authority::new("localhost", Some(443));
        assert_eq!(&authority.host_port_string(), "localhost:443");

        let authority = Authority::new("::1", Some(50051));
        assert_eq!(&authority.host_port_string(), "[::1]:50051");

        let authority = Authority::new("::1", None);
        assert_eq!(&authority.host_port_string(), "::1");
    }
}