sdk/fidl/fuchsia.net.routing/routing.fidl

// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

library fuchsia.net.routing;

using fuchsia.net;

const uint32 ROUTING_TABLE_ENTRIES_LIMIT = 256;
const uint32 DEFAULT_METRIC = 100; // TODO(7889): Support default vales on tables.

/// A mapping between a destination subnet and an egress.
/// This serves as a key to a routing table entry.
/// A routing table may have multiple entries for the same destination subnet
/// with a different egress.
table Route {
    /// Destination subnet
    /// subnet.prefix_len = 0 is interpreted as "default" route. See IETF RFC 4632.
    1: fuchsia.net.Subnet subnet;

    /// Where the packet for the destination subnet goes to: egress points.
    /// At least one of nicid and next_hop MUST be present.
    2: uint32 nicid;

    /// At least one of nicid and next_hop MUST be present.
    /// Address of the next hop router to reach destination subnet.
    3: fuchsia.net.IpAddress next_hop;
};

/// The information source from which the routing entry metric is drawn.
enum MetricSource : uint8 {
    /// Assigned manually.
    MANUAL = 0;
    /// Follows the value of the egress interface.
    INTERFACE = 1;
};

/// Properties that management plane utilizes for each route.
/// If exists, may be updated dynamically.
table RouteProperties {
    /// A value to indicate the preference.
    /// Lower values take precedence. Breaking ties is up to the implementation of the protocol.
    1: uint32 metric; // TODO(7889): Add default 100.
};

/// An element of a route table.
/// A route table is represented as a vector of RouteTableEntry.
table RouteTableEntry {
    /// Route is the identifier of an RouteTableEntry.
    1: Route route;

    /// Any associated properties for the route.
    2: RouteProperties properties;
};

/// A choice of route change action.
flexible union RouteChange {
    /// Add a new Route to the table. If the Route already exists, an error is returned.
    1: RouteTableEntry add;
    /// Delete a Route from the table. If the Route does not exist, an error is returned.
    2: Route delete;
    /// Update the properties of a given Route. If the Route does not exist, an error is returned.
    3: RouteTableEntry update;
};

enum Error {
    OK = 0;

    /// Generic error for argument.
    INVALID_ARGS = 1;
    INTERFACE_NOT_FOUND = 2;
    ROUTE_NOT_FOUND = 3;

    /// Generic error for ChangeRouteTable method, when no specific error is applicable.
    ROUTE_CHANGE_FAILURE = 4;
};

[Discoverable]
protocol Routing {
    /// Returns the routing metric associated with the interface specified by the NICID.
    GetInterfaceMetric(uint32 nicid) -> (uint32 metric) error Error;

    /// Update the routing metric associated with the interface specified by the NICID.
    SetInterfaceMetric(uint32 nicid, uint32 metric) -> () error Error;

    /// Returns routing table under operation.
    GetRouteTable() -> (vector<RouteTableEntry>:ROUTING_TABLE_ENTRIES_LIMIT entries) error Error;

    /// A set of changes to commit together: all-or-nothing.
    /// The changes MUST be sequentially coherent.
    ///   eg. add x - update x is coherent
    ///   eg. update x - add x is not.
    /// If any of RouteChange is incoherent, none of the RouteChanges in
    /// a single ChangeRouteTable shall be committed.
    ChangeRouteTable(vector<RouteChange>:ROUTING_TABLE_ENTRIES_LIMIT changes) -> () error Error;
};