diff --git a/src/yggdrasil/api.go b/src/yggdrasil/api.go index d1753b69..f69ef7e9 100644 --- a/src/yggdrasil/api.go +++ b/src/yggdrasil/api.go @@ -16,29 +16,37 @@ import ( ) // Peer represents a single peer object. This contains information from the -// preferred switch port for this peer, although there may be more than one in -// reality. +// preferred switch port for this peer, although there may be more than one +// active switch port connection to the peer in reality. +// +// This struct is informational only - you cannot manipulate peer connections +// using instances of this struct. You should use the AddPeer or RemovePeer +// functions instead. type Peer struct { - PublicKey crypto.BoxPubKey - Endpoint string - BytesSent uint64 - BytesRecvd uint64 - Protocol string - Port uint64 - Uptime time.Duration + PublicKey crypto.BoxPubKey // The public key of the remote node + Endpoint string // The connection string used to connect to the peer + BytesSent uint64 // Number of bytes sent to this peer + BytesRecvd uint64 // Number of bytes received from this peer + Protocol string // The transport protocol that this peer is connected with, typically "tcp" + Port uint64 // Switch port number for this peer connection + Uptime time.Duration // How long this peering has been active for } // SwitchPeer represents a switch connection to a peer. Note that there may be // multiple switch peers per actual peer, e.g. if there are multiple connections // to a given node. +// +// This struct is informational only - you cannot manipulate switch peer +// connections using instances of this struct. You should use the AddPeer or +// RemovePeer functions instead. type SwitchPeer struct { - PublicKey crypto.BoxPubKey - Coords []uint64 - BytesSent uint64 - BytesRecvd uint64 - Port uint64 - Protocol string - Endpoint string + PublicKey crypto.BoxPubKey // The public key of the remote node + Coords []uint64 // The coordinates of the remote node + BytesSent uint64 // Number of bytes sent via this switch port + BytesRecvd uint64 // Number of bytes received via this switch port + Port uint64 // Switch port number for this switch peer + Protocol string // The transport protocol that this switch port is connected with, typically "tcp" + Endpoint string // The connection string used to connect to the switch peer } // DHTEntry represents a single DHT entry that has been learned or cached from @@ -64,32 +72,36 @@ type NodeInfoPayload []byte // congestion and a list of switch queues created in response to congestion on a // given link. type SwitchQueues struct { - Queues []SwitchQueue - Count uint64 - Size uint64 - HighestCount uint64 - HighestSize uint64 - MaximumSize uint64 + Queues []SwitchQueue // An array of SwitchQueue objects containing information about individual queues + Count uint64 // The current number of active switch queues + Size uint64 // The current total size of active switch queues + HighestCount uint64 // The highest recorded number of switch queues so far + HighestSize uint64 // The highest recorded total size of switch queues so far + MaximumSize uint64 // The maximum allowed total size of switch queues, as specified by config } -// SwitchQueue represents a single switch queue, which is created in response -// to congestion on a given link. +// SwitchQueue represents a single switch queue. Switch queues are only created +// in response to congestion on a given link and represent how much data has +// been temporarily cached for sending once the congestion has cleared. type SwitchQueue struct { - ID string - Size uint64 - Packets uint64 - Port uint64 + ID string // The ID of the switch queue + Size uint64 // The total size, in bytes, of the queue + Packets uint64 // The number of packets in the queue + Port uint64 // The switch port to which the queue applies } -// Session represents an open session with another node. +// Session represents an open session with another node. Sessions are opened in +// response to traffic being exchanged between two nodes using Conn objects. +// Note that sessions will automatically be closed by Yggdrasil if no traffic is +// exchanged for around two minutes. type Session struct { - PublicKey crypto.BoxPubKey - Coords []uint64 - BytesSent uint64 - BytesRecvd uint64 - MTU uint16 - Uptime time.Duration - WasMTUFixed bool + PublicKey crypto.BoxPubKey // The public key of the remote node + Coords []uint64 // The coordinates of the remote node + BytesSent uint64 // Bytes sent to the session + BytesRecvd uint64 // Bytes received from the session + MTU uint16 // The maximum supported message size of the session + Uptime time.Duration // How long this session has been active for + WasMTUFixed bool // This field is no longer used } // GetPeers returns one or more Peer objects containing information about active diff --git a/src/yggdrasil/doc.go b/src/yggdrasil/doc.go index 3010765a..44d39b66 100644 --- a/src/yggdrasil/doc.go +++ b/src/yggdrasil/doc.go @@ -125,6 +125,9 @@ Using Connections Conn objects are implementations of io.ReadWriteCloser, and as such, you can Read, Write and Close them as necessary. +Each Read or Write operation can deal with a buffer with a maximum size of 65535 +bytes - any bigger than this and the operation will return an error. + For example, to write to the Conn from the supplied buffer: buf := []byte{1, 2, 3, 4, 5} @@ -152,5 +155,22 @@ When you are happy that a connection is no longer required, you can discard it: // ... } +Limitations + +You should be aware of the following limitations when working with the Yggdrasil +library: + +Individual messages written through Yggdrasil connections can not exceed 65535 +bytes in size. Yggdrasil has no concept of fragmentation, so if you try to send +a message that exceeds 65535 bytes in size, it will be dropped altogether and +an error will be returned. + +Yggdrasil connections are unreliable by nature. Messages are delivered on a +best-effort basis, and employs congestion control where appropriate to ensure +that congestion does not affect message transport, but Yggdrasil will not +retransmit any messages that have been lost. If reliable delivery is important +then you should manually implement acknowledgement and retransmission of +messages. + */ package yggdrasil