bgp_rib_policy.h

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/*
 * Copyright (c) 2016 Juniper Networks, Inc. All rights reserved.
 */

#ifndef SRC_BGP_BGP_RIB_POLICY_H_
#define SRC_BGP_BGP_RIB_POLICY_H_

#include "bgp/bgp_proto.h"

//
// This class represents the export policy for a rib. Given that we do not
// currently support any real policy configuration, this is pretty trivial
// for now.
//
// Including the AS number as part of the policy results in creation of a
// different RibOut for every neighbor AS that we peer with. This allows a
// simplified implementation of the sender side AS path loop check. In most
// practical deployment scenarios all eBGP peers will belong to the same
// neighbor AS anyway.
//
// Including AS override as part of the policy results in creation of a
// different RibOuts for neighbors that need and don't AS override.
//
// Including the nexthop as part of the policy results in creation of a
// different RibOut for each set of BGPaaS clients that belong to the same
// subnet. This allows us to rewrite the nexthop to the specified value.
//
// Including the CPU affinity as part of the RibExportPolicy allows us to
// artificially create more RibOuts than otherwise necessary. This is used
// to achieve higher concurrency at the expense of creating more state.
//
// Including llgr as part of the policy results in the creation of a different
// ribout for each set of peers that do (or do not) support long lived
// graceful restart functionality. In order to ensure correctness, we need
// to not advertise LLGR_STALE community to peers who do not support LLGR.
// Instead, we should bring down the local pref to make the paths less
// preferable.
//
// Adding as4_supported so that peers who support 4 byte AS can be grouped
// together. For non AS4 neighbors, we need to add AS_TRANS in AS_PATH if
// local AS does not fit in 2 bytes.
//
struct RibExportPolicy {
    enum Encoding {
        BGP,
        XMPP,
    };

    struct RemovePrivatePolicy {
        RemovePrivatePolicy();

        bool enabled;
        bool all;
        bool replace;
        bool peer_loop_check;
    };

    RibExportPolicy();
    explicit RibExportPolicy(uint32_t cluster_id);
    RibExportPolicy(BgpProto::BgpPeerType type, Encoding encoding,
        int affinity, uint32_t cluster_id);
    RibExportPolicy(BgpProto::BgpPeerType type, Encoding encoding,
        as_t as_number, bool as_override, bool llgr, bool as4_supported,
        int affinity, uint32_t cluster_id, as_t local_as_number = 0);
    RibExportPolicy(BgpProto::BgpPeerType type, Encoding encoding,
        as_t as_number, bool as_override, bool llgr, bool as4_supported,
        IpAddress nexthop, int affinity, uint32_t cluster_id,
        std::vector<std::string> &default_tunnel_encap_list,
        as_t local_as_number = 0);
    void SetRemovePrivatePolicy(bool all, bool replace, bool peer_loop_check);
    bool operator<(const RibExportPolicy &rhs) const;

    BgpProto::BgpPeerType type;
    Encoding encoding;
    as_t as_number;
    as_t local_as_number;
    bool as_override;
    IpAddress nexthop;
    int affinity;
    bool llgr;
    bool as4_supported;
    uint32_t cluster_id;
    RemovePrivatePolicy remove_private;
    std::vector<std::string> default_tunnel_encap_list;
};

#endif  // SRC_BGP_BGP_RIB_POLICY_H_