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//! Configuration logic for tor-ptmgr.
use std::net::SocketAddr;
use derive_builder::Builder;
use serde::{Deserialize, Serialize};
use tor_config::{impl_standard_builder, CfgPath, ConfigBuildError};
use tor_linkspec::PtTransportName;
use tor_socksproto::SocksVersion;
use crate::ipc::PtClientMethod;
/// A single pluggable transport.
///
/// Pluggable transports are programs that transform and obfuscate traffic on
/// the network between a Tor client and a Tor bridge, so that an adversary
/// cannot recognize it as Tor traffic.
///
/// A pluggable transport can be either _managed_ (run as an external process
/// that we launch and monitor), or _unmanaged_ (running on a local port, not
/// controlled by Arti).
#[derive(Clone, Debug, Builder, Eq, PartialEq)]
#[builder(derive(Debug, Serialize, Deserialize))]
#[builder(build_fn(error = "ConfigBuildError", validate = "Self::validate"))]
pub struct TransportConfig {
/// Names of the transport protocols that we are willing to use from this transport.
///
/// (These protocols are arbitrary identifiers that describe which protocols
/// we want. They must match names that the binary knows how to provide.)
//
// NOTE(eta): This doesn't use the list builder stuff, because you're not likely to
// set this field more than once.
pub(crate) protocols: Vec<PtTransportName>,
/// The path to the binary to run, if any.
///
/// This needs to be the path to some executable file on disk.
///
/// Present only for managed transports.
#[builder(default, setter(strip_option))]
pub(crate) path: Option<CfgPath>,
/// One or more command-line arguments to pass to the binary.
///
/// Meaningful only for managed transports.
// TODO: Should this be OsString? That's a pain to parse...
//
// NOTE(eta): This doesn't use the list builder stuff, because you're not likely to
// set this field more than once.
#[builder(default)]
pub(crate) arguments: Vec<String>,
/// The location at which to contact this transport.
///
/// Present only for unmanaged transports.
#[builder(default, setter(strip_option))]
pub(crate) proxy_addr: Option<SocketAddr>,
/// If true, launch this transport on startup. Otherwise, we launch
/// it on demand.
///
/// Meaningful only for managed transports.
#[builder(default)]
pub(crate) run_on_startup: bool,
}
impl_standard_builder! { TransportConfig: !Default }
impl TransportConfig {
/// Return true if this transport is managed.
pub(crate) fn is_managed(&self) -> bool {
self.path.is_some()
}
/// If this is an unmanaged transport, return a client method that can be
/// used to contact it.
pub(crate) fn cmethod_for_unmanaged_pt(&self) -> Option<PtClientMethod> {
self.proxy_addr.map(|a| PtClientMethod {
// TODO: Someday we might want to support other protocols;
// but for now, let's see if we can get away with just socks5.
kind: SocksVersion::V5,
endpoint: a,
})
}
}
impl TransportConfigBuilder {
/// Inspect the list of protocols (ie, transport names)
///
/// If none have yet been specified, returns an empty list.
pub fn get_protocols(&self) -> &[PtTransportName] {
self.protocols.as_deref().unwrap_or_default()
}
/// Make sure that this builder is internally consistent.
fn validate(&self) -> Result<(), ConfigBuildError> {
match (&self.path, &self.proxy_addr) {
(Some(_), Some(_)) => Err(ConfigBuildError::Inconsistent {
fields: vec!["path".into(), "proxy_addr".into()],
problem: "Cannot provide both path and proxy_addr".into(),
}),
// TODO: There is no ConfigBuildError for "one of two fields is missing."
(None, None) => Err(ConfigBuildError::MissingField {
field: "{path or proxy_addr}".into(),
}),
(None, Some(_)) => {
if self.arguments.as_ref().is_some_and(|v| !v.is_empty()) {
Err(ConfigBuildError::Inconsistent {
fields: vec!["proxy_addr".into(), "arguments".into()],
problem: "Cannot provide arguments for an unmanaged transport".into(),
})
} else if self.run_on_startup.is_some() {
Err(ConfigBuildError::Inconsistent {
fields: vec!["proxy_addr".into(), "run_on_startup".into()],
problem: "run_on_startup is meaningless for an unmanaged transport".into(),
})
} else {
Ok(())
}
}
(Some(_), None) => Ok(()),
}
}
}