5 

     6     Firstly, this defines a set of abstract interfaces that model the actual implementation as built on top of the

     7     socket packages's network-layer implementation:

     8 

     9 

    10     Interfaces:

    11 

    12         Transport           - very abstract interface that embodies the notion of sending something somewhere

    13 

    14             ConnectedTransport      - connection-oriented transport

    15             

    16                 Stream                  - connection-oriented full-duplex byte stream (reliable, sequenced)

    17     

    18                 PacketStream            - connection-oriented full-duplex packet-oriented communication

    19  

    20 

    21             UnconnectedTransport    - non-connection-oriented transport dealing with packets

    22 

    23                 Peer                    - connectionless packet-oriented communication

    24 

    25 

    26         Endpoint        - some transport-level endpoint (local/remote address/socket)

    27 

    28             Client          - connection-oriented endpoint that can establish a Transport to some remote Service

    29 

    30             Service         - listening endpoint that recieves connections from remote Clients and represents those as Transports

    31 

    32 

    33     Next, there are some mid-level helpers, mostly for dealing with 

    34 

    35 

    36     Then there is are implementations of these interfaces for specific protocols, layering on top of the socket module,

    37     or other application-level protocols.

    38 

    39     TCP:

    40         TCP implementation using a SOCK_STREAM socket.

    41 

    42         Stream          - connected TCP socket with TCP's byte stream semantics

    43 

    44         Service         - TCP socket accept()'ing Streams from remote Clients

    45 

    46         Client          - TCP socket connect()'ing to a remote Service

    47 

    48 

    49     UDP:

    50         UDP implementation using a SOCK_DGRAM socket.

    51 

    52         Peer            - bind()'d UDP socket without any connection

    53 

    54         Client          - connect()'d UDP socket, representing a PacketStream

    55 

    56 

    57     UNIX:

    58         UNIX socket implementation support both SOCK_STREAM and SOCK_DGRAM.

    59 

    60         XXX: verify that this is correct...

    61 

    62         Stream          - connected AF_UNIX SOCK_STREAM

    63 

    64         Service         - accept()'ing AF_UNIX socket of either SOCK_STREAM mode

    65 

    66         Client          - connect()'ing AF_UNIX socket of SOCK_STREAM mode

    67 

    68         Peer            - bind()'d AF_UNIX socket of SOCK_DGRAM mode

    69 

    70     SCTP:

    71         SCTP implementation offering both SOCK_SEQPACKET and SOCK_STREAM -based socket interfaces.

    72 

    73         Stream          - a PacketStream carried by an Association

    74 

    75         Association     - a Transport that represents a SCTP association between a local and remote Endpoint

    76 

    77         Peer            - one-to-many style interface, with a single Peer holding multiple Associations

    78 

    79         Service         - a one-to-one style listen()'ing interface which accepts Associations from remote Endpoints

    80 

    81         Client          - a one-to-one style connect()'ing interface which establishes Associations with remote Endpoints

    82 

    83     SSL:

    84         SSL implementation using either OpenSSL or gnutls.

    85 

    86         Stream          - tcp.Stream carrying an encrypted byte stream

    87 

    88         Service         - tcp.Service accepting connections from SSL endpoints

    89 

    90         Client          - tcp.Client connecting to an SSL service

    91 

    92     SOCKS:

    93         SOCKSv5 client implementing TCP client serviecs.

    94 

    95         Stream          - tcp.Stream carried over a SOCKSv5 connections

    96 

    97         Client          - tcp.Client connecting via a SOCKSv5 server

    98