node_messages_generator.h | Explore in Territory

// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// no-include-guard-because-multiply-included

// This file defines the internal messages which can be sent on a NodeLink
// between two ipcz nodes.

IPCZ_MSG_BEGIN_INTERFACE

// Initial greeting sent by a broker node when a ConnectNode() is issued without
// the IPCZ_CONNECT_NODE_TO_BROKER flag, implying that the receiving node is a
// non-broker.
IPCZ_MSG_BEGIN(ConnectFromBrokerToNonBroker, IPCZ_MSG_ID(0))
  IPCZ_MSG_BEGIN_VERSION(0)
    // The name of the broker node.
    IPCZ_MSG_PARAM(NodeName,  … } 

// Initial greeting sent by a non-broker node when ConnectNode() is invoked with
// IPCZ_CONNECT_NODE_TO_BROKER. The sending non-broker node expects to receive a
// corresponding ConnectFromBrokerToNonBroker
IPCZ_MSG_BEGIN(ConnectFromNonBrokerToBroker, IPCZ_MSG_ID(1))
  IPCZ_MSG_BEGIN_VERSION(0)
    // The highest protocol version known and desired by the sender.
    IPCZ_MSG_PARAM(uint32_t,  … } 

// Sent from a non-broker to its broker when calling ConnectNode() with
// IPCZ_CONNECT_NODE_SHARE_BROKER. In this case the transport given to
// ConnectNode() is passed along to the broker via this message, and the broker
// assumes the other end of that transport belongs to a new non-broker node who
// wishes to join the network.
//
// The broker performs an initial handshake with the referred node -- it waits
// for a ConnectToReferredBroker message on the new transport and then sends a
// ConnectToReferredNonBroker over the same transport, as well as a
// NonBrokerReferralAccepted message back to the original referrer who sent this
// request.
//
// If this request is invalid or the broker otherwise fails to establish a link
// to the referred node, the broker instead responds to the referrer with a
// NonBrokerReferralRejected message.
IPCZ_MSG_BEGIN(ReferNonBroker, IPCZ_MSG_ID(2))
  IPCZ_MSG_BEGIN_VERSION(0)
    // A unique (for the transmitting NodeLink) identifier for this referral,
    // used to associate a corresponding NonBrokerReferralAccepted/Rejected
    // response from the broker.
    IPCZ_MSG_PARAM(uint64_t,  … } 

// Sent from a non-broker to its tentative broker when calling ConnectNode()
// with IPCZ_CONNECT_NODE_INHERIT_BROKER. The other end of the transport given
// to that ConnectNode() call must itself be given to ConnectNode() by some
// other non-broker calling with IPCZ_CONNECT_NODE_SHARE_BROKER. That other node
// will pass the transport to the broker using a ReferNonBroker message.
//
// Once ConnectToReferredBroker is received by the broker on the new transport,
// the broker sends back a ConnectToReferredNonBroker to the sender of this
// message, as well as a NonBrokerReferralAccepted message to the original
// referrer.
IPCZ_MSG_BEGIN(ConnectToReferredBroker, IPCZ_MSG_ID(3))
  IPCZ_MSG_BEGIN_VERSION(0)
    // The highest protocol version known and desired by the sender.
    IPCZ_MSG_PARAM(uint32_t,  … } 

// Sent from a broker to a referred non-broker node over a transport that was
// provided to the broker by some other non-broker via a ReferNonBroker message.
//
// This is sent to the referred node if and only if the referral has been
// accepted by the broker, and only the broker has received a
// ConnectToReferredBroker message over the same transport that sends this
// message.
IPCZ_MSG_BEGIN(ConnectToReferredNonBroker, IPCZ_MSG_ID(4))
  IPCZ_MSG_BEGIN_VERSION(0)
    // The newly assigned name of the node receiving this message.
    IPCZ_MSG_PARAM(NodeName,  … } 

// Sent from a broker to a non-broker who previously referred another node via
// ReferNonBroker. This message indicates that the referral was accepted, and it
// provides objects and details necessary for the recipient (i.e. the referrer)
// to establish a direct NodeLink to the referred node.
IPCZ_MSG_BEGIN(NonBrokerReferralAccepted, IPCZ_MSG_ID(5))
  IPCZ_MSG_BEGIN_VERSION(0)
    // A unique identifier for the referral in question, as provided by the
    // original ReferNonBroker message sent by the receipient of this message.
    IPCZ_MSG_PARAM(uint64_t,  … } 

// Sent from a broker to a non-broker who previously referred another node via
// ReferNonBroker. This message indicates that the referral was rejected. No
// link to the referred node has been established by the broker, and none will
// be provided to the referrer. This can occur for example if the referred node
// disconnects from the broker before establishing a handshake.
IPCZ_MSG_BEGIN(NonBrokerReferralRejected, IPCZ_MSG_ID(6))
  IPCZ_MSG_BEGIN_VERSION(0)
    // A unique identifier for the referral in question, as provided by the
    // original ReferNonBroker message sent by the receipient of this message.
    IPCZ_MSG_PARAM(uint64_t,  … } 

// Sent from one broker to another to establish an initial link between two
// distinct node networks. Once two brokers are connected their networks are
// effectively merged and nodes in either network can become interconnected by
// ipcz.
IPCZ_MSG_BEGIN(ConnectFromBrokerToBroker, IPCZ_MSG_ID(7))
  IPCZ_MSG_BEGIN_VERSION(0)
    // The name of the sending node.
    IPCZ_MSG_PARAM(NodeName,  … } 

// Sent to a broker to ask for an introduction to one of the non-broker nodes in
// its own network. This may be sent either from a non-broker in the same
// network, or a broker from another network.
//
// The non-broker to be introduced to the sender is identified by `name`. If the
// broker is willing and able to comply with this request, it will send an
// AcceptIntroduction message (see below) to both the sender of this message and
// the node identified by `name`.
//
// If the broker does not know the node named `name`, it will send only a
// RejectIntroduction message back to the sender to indicate failure.
IPCZ_MSG_BEGIN(RequestIntroduction, IPCZ_MSG_ID(10))
  IPCZ_MSG_BEGIN_VERSION(0)
    IPCZ_MSG_PARAM(NodeName,  … } 

// Introduces one node to another. Sent only by broker nodes and must only be
// accepted from broker nodes.
IPCZ_MSG_BEGIN(AcceptIntroduction, IPCZ_MSG_ID(11))
  IPCZ_MSG_BEGIN_VERSION(0)
    // The name of the node being introduced to the recipient of this message.
    IPCZ_MSG_PARAM(NodeName,  … } 

// Sent to a node in response to RequestIntroduction if the broker receiving
// that message did not recognize or otherwise could not introduce the requested
// node.
IPCZ_MSG_BEGIN(RejectIntroduction, IPCZ_MSG_ID(12))
  IPCZ_MSG_BEGIN_VERSION(0)
    // The name of the node whose introduction cannot be fulfilled.
    IPCZ_MSG_PARAM(NodeName,  … } 

// Sent from a broker to another broker to request that the receiving broker
// introduce a named node in its own network to a named node in the sender's
// network.
IPCZ_MSG_BEGIN(RequestIndirectIntroduction, IPCZ_MSG_ID(13))
  IPCZ_MSG_BEGIN_VERSION(0)
    // The name of the node to be introduced on the sender's own network.
    IPCZ_MSG_PARAM(NodeName,  … } 

// Shares a new buffer to support allocation of blocks of `block_size` bytes.
// The sender must initialize an appropriate BlockAllocator within the buffer's
// memory before sending this message.
IPCZ_MSG_BEGIN(AddBlockBuffer, IPCZ_MSG_ID(14))
  IPCZ_MSG_BEGIN_VERSION(0)
    // The ID of the new buffer as allocated by the NodeLinkMemory on the
    // NodeLink transmitting this message.
    IPCZ_MSG_PARAM(BufferId,  … } 

// Conveys the contents of a parcel.
IPCZ_MSG_BEGIN(AcceptParcel, IPCZ_MSG_ID(20))
  IPCZ_MSG_BEGIN_VERSION(0)
    // The SublinkId linking the source and destination Routers along the
    // transmitting NodeLink.
    IPCZ_MSG_PARAM(SublinkId,  … } 

// Conveys partial parcel contents, namely just its attached driver objects.
// When a parcel with driver objects cannot be transmitted directly to its
// destination, this message is split off and relayed through the broker while
// the rest of the parcel contents are sent directly, without the objects
// attached. The receiving node can reconstitute the full parcel once both
// messages are received.
IPCZ_MSG_BEGIN(AcceptParcelDriverObjects, IPCZ_MSG_ID(21))
  IPCZ_MSG_BEGIN_VERSION(0)
    // The SublinkId linking the source and destination Routers along the
    // transmitting NodeLink.
    IPCZ_MSG_PARAM(SublinkId,  … } 

// Notifies a node that the route has been closed on one side. This message
// always pertains to the side of the route opposite of the router receiving it,
// guaranteed by the fact that the closed side of the route only transmits this
// message outward once its terminal router is adjacent to the central link.
IPCZ_MSG_BEGIN(RouteClosed, IPCZ_MSG_ID(22))
  IPCZ_MSG_BEGIN_VERSION(0)
    // In the context of the receiving NodeLink, this identifies the specific
    // Router to receive this message.
    IPCZ_MSG_PARAM(SublinkId,  … } 

// Notifies a specific router that its route from the direction of this link has
// been unexpectedly disconnected (e.g. due to a node crashing). This is
// essentially the same as route closure but without respect for complete parcel
// sequence delivery.
IPCZ_MSG_BEGIN(RouteDisconnected, IPCZ_MSG_ID(23))
  IPCZ_MSG_BEGIN_VERSION(0)
    IPCZ_MSG_PARAM(SublinkId,  … } 

// Informs a router that its outward peer can be bypassed. Given routers X and Y
// on the central link, and a router Z as Y's inward peer:
//
//     X ==== (central) ==== Y ======== Z
//
// Once Y successfully locks the central link, Y may send this message to Z
// with sufficient information for Z to establish a direct link to X. Z
// accomplishes this via an AcceptBypassLink message to X's node.
//
// Note that this message is only used when X and Y belong to different nodes.
// If X and Y belong to the same node, then Y sends Z a BypassPeerWithLink
// message instead.
IPCZ_MSG_BEGIN(BypassPeer, IPCZ_MSG_ID(30))
  IPCZ_MSG_BEGIN_VERSION(0)
    // Identifies the router to receive this message.
    IPCZ_MSG_PARAM(SublinkId,  … } 

// Provides a router with a new outward link to replace its existing outward
// link to some other node. Given routers X and Y on the central link, and a
// router Z as Y's inward peer:
//
//     X ==== (central) ==== Y ======== Z
//
// Z sends this message to X's node to establish a new direct link to X. Both
// X's and Z's existing links to Y are left intact in a decaying state:
//
//         - - - Y - - -
//       /               \
//     X === (central) === Z
//
// The recipient of this message must send a StopProxying message to Y, as well
// as a ProxyWillStop message to Z, in order for those decaying links to be
// phased out.
//
// Z must send this message to X only after receiving a BypassPeer request from
// Y. That request signifies that X's node has been adequately prepared by Y to
// authenticate this request from Z.
IPCZ_MSG_BEGIN(AcceptBypassLink, IPCZ_MSG_ID(31))
  IPCZ_MSG_BEGIN_VERSION(0)
    // Identifies the node of the targeted router's own outward peer, as well as
    // the sublink their nodes use to route between those routers. In the above
    // scenario these fields identify the link between X and Y to be replaced,
    // and as a consequence they uniquely identify X itself to the recipient.
    IPCZ_MSG_PARAM(NodeName,  … } 

// Informs a router about how many more parcels it can expect to receive from
// its inward and outward peers before it can stop proxying between them and
// cease to exist. Given routers X, Y, and Z in a configuration resulting from
// a BypassPeer from Y to Z, followed by an AcceptBypassLink from Z to X:
//
//         - - - Y - - -
//       /               \
//     X === (central) === Z
//
// This message is sent from X to Y to provide the final length of the sequence
// of parcels routed through Y in either direction, now that X and Z have
// established a direct connection.
IPCZ_MSG_BEGIN(StopProxying, IPCZ_MSG_ID(32))
  IPCZ_MSG_BEGIN_VERSION(0)
    // Identifies the router to receive this message.
    IPCZ_MSG_PARAM(SublinkId,  … } 

// Informs a router about how many more parcels it can expect to receive from
// its outward peer. Given routers X, Y, and Z in a configuration resulting from
// a BypassPeer from Y to Z, followed by an AcceptBypassLink from Z to X:
//
//         - - - Y - - -
//       /               \
//     X === (central) === Z
//
// This message is sent from X to Z to provide the final length of the sequence
// of parcels routed from X to Y (and therefore from Y to Z), now that X and Z
// have established a direct connection.
IPCZ_MSG_BEGIN(ProxyWillStop, IPCZ_MSG_ID(33))
  IPCZ_MSG_BEGIN_VERSION(0)
    // Identifies the router to receive this message.
    IPCZ_MSG_PARAM(SublinkId,  … } 

// Informs a router that its outward peer can be bypassed, and provides a new
// link with which to execute that bypass. Given the following arrangement where
// X, Y, and Z are routers; AND X and Y live on the same node as each other:
//
//     X ==== (central) ==== Y ======== Z
//
// Y sends this to Z to establish a new link (over the same NodeLink) directly
// between Z and X. Both X's and Z's existing links to Y are left intact in a
// decaying state:
//
//         - - - Y - - -
//       /               \
//     X === (central) === Z
//
// Note that unlike with BypassPeer/AcceptBypassLink, there is no need to
// authenticate this request, as it's only swapping one sublink out for another
// along the same NodeLink.
IPCZ_MSG_BEGIN(BypassPeerWithLink, IPCZ_MSG_ID(34))
  IPCZ_MSG_BEGIN_VERSION(0)
    // Identifies the router to receive this message.
    IPCZ_MSG_PARAM(SublinkId,  … } 

// Provides a router with the final length of the sequence of outbound parcels
// that will be routed to it via its decaying inward link. Given the following
// arrangement where X, Y, and Z are routers; X and Y live on the same node
// as each other: and Y has already sent a BypassPeerWithLink message to Z:
//
//         - - - Y - - -
//       /               \
//     X === (central) === Z
//
// This message is sent from Z back to Y, informing Y of the last parcel it can
// expect to receive from Z, now that X and Z are connected directly.
IPCZ_MSG_BEGIN(StopProxyingToLocalPeer, IPCZ_MSG_ID(35))
  IPCZ_MSG_BEGIN_VERSION(0)
    // Identifies the router to receive this message.
    IPCZ_MSG_PARAM(SublinkId,  … } 

// Hints to the target router that it should flush its state. Generally sent to
// catalyze route reduction or elicit some other state change which was blocked
// on some other work being done first by the sender of this message.
IPCZ_MSG_BEGIN(FlushRouter, IPCZ_MSG_ID(36))
  IPCZ_MSG_BEGIN_VERSION(0)
    IPCZ_MSG_PARAM(SublinkId,  … } 

// Requests allocation of a shared memory region of a given size. If the
// recipient can comply, they will send back a corresponding ProvideMemory
// message with a serialized memory region. This message is only sent to a
// node's allocation delegate (usually the broker), which is established by
// providing the IPCZ_CONNECT_NODE_TO_ALLOCATION_DELEGATE flag to ConnectNode().
IPCZ_MSG_BEGIN(RequestMemory, IPCZ_MSG_ID(64))
  IPCZ_MSG_BEGIN_VERSION(0)
    IPCZ_MSG_PARAM(uint32_t,  … } 

// Provides a new shared buffer to the receiver, owned exclusively by the
// receiver. The receiver is free to duplicate this buffer and share it with
// other nodes.
IPCZ_MSG_BEGIN(ProvideMemory, IPCZ_MSG_ID(65))
  IPCZ_MSG_BEGIN_VERSION(0)
    IPCZ_MSG_PARAM(uint32_t,  … } 

// Sends a message payload to the broker to be relayed to another node. Used to
// relay messages which carry driver objects through the broker when they cannot
// be transmitted directly between their source and destination nodes.
IPCZ_MSG_BEGIN(RelayMessage, IPCZ_MSG_ID(66))
  IPCZ_MSG_BEGIN_VERSION(0)
    // The node to which this message's contents should ultimately be relayed.
    IPCZ_MSG_PARAM(NodeName,  … } 

// Relays a message payload from an intermediate broker to its destination. This
// is the continuation of RelayMessage above. Must only be accepted on a broker.
IPCZ_MSG_BEGIN(AcceptRelayedMessage, IPCZ_MSG_ID(67))
  IPCZ_MSG_BEGIN_VERSION(0)
    // The node which originally requested that the broker relay this message.
    IPCZ_MSG_PARAM(NodeName,  … } 

IPCZ_MSG_END_INTERFACE
chromium/third_party/ipcz/src/ipcz/node_messages_generator.h
