FreeBSD/Linux Kernel Cross Reference
sys/modules/netgraph/cisco/ng_cisco.4

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    .\" Author: Archie Cobbs <archie@freebsd.org>
    .\"
    .\" $FreeBSD$
    .\" $Whistle: ng_cisco.8,v 1.5 1999/01/25 23:46:26 archie Exp $
    .\"
    .Dd January 19, 1999
    .Dt NG_CISCO 4
    .Os FreeBSD
    .Sh NAME
    .Nm ng_cisco
    .Nd Cisco HDLC protocol netgraph node type
    .Sh SYNOPSIS
    .Fd #include <netinet/in.h>
    .Fd #include <netgraph/ng_cisco.h>
    .Sh DESCRIPTION
    The
    .Nm cisco
    node type performs encapsulation and de-encapsulation of packets
    using the Cisco HDLC protocol. This is a fairly simple
    protocol for the transmission of packets across
    high speed synchronous lines. Each packet is prepended with
    an Ethertype, indicating the protocol. There is also a
    .Dq keep alive
    and an
    .Dq inquire
    capability.
    .Pp
    The
    .Dv downstream
    hook should connect to the synchronous line. On the other side
    of the node are the
    .Dv inet ,
    .Dv atalk ,
    and
    .Dv ipx
    hooks, which transmit and receive raw IP, AppleTalk, and IPX packets,
    respectively.  Typically these hooks would connect to the corresponding
    hooks on an
    .Xr ng_iface 4
    type node.
    .Sh IP Configuration
    In order to function properly for IP traffic, the node must be informed
    of the local IP address and netmask setting.  This is because the protocol
    includes an
    .Dq inquire
    packet which we must be prepared to answer.
    There are two ways to accomplish this, manually and automatically.
    .Pp
    Whenever such an inquire packet is received, the node sends a
    .Dv NGM_CISCO_GET_IPADDR
    control message to the peer node connected to the
    .Dv inet
    hook (if any).
    If the peer responds, then that response is used. This is the automatic method.
    .Pp
    If the peer does not respond, the node falls back on its cached value
    for the IP address and netmask. This cached value can be set at any time
    with a
    .Dv NGM_CISCO_SET_IPADDR
    message, and this is the manual method.
    .Pp
    If the
    .Dv inet
    hook is connected to the
    .Dv inet
    hook of an
    .Xr ng_iface 4
   node, as is usually the case, then configuration is automatic as the 
   .Xr ng_iface 4
   understands the
   .Dv NGM_CISCO_GET_IPADDR
   message.
   .Sh HOOKS
   This node type supports the following hooks:
   .Pp
   .Bl -tag -width foobarbazio
   .It Dv downstream
   The connection to the synchronous line.
   .It Dv inet
   IP hook.
   .It Dv atalk
   AppleTalk hook.
   .It Dv ipx
   IPX hook
   .El
   .Sh CONTROL MESSAGES
   This node type supports the generic control messages, plus the following:
   .Bl -tag -width foo
   .It Dv NGM_CISCO_SET_IPADDR
   This command takes an array of two
   .Dv "struct in_addr"
   arguments. The first is the IP address of the corresponding interface
   and the second is the netmask.
   .It Dv NGM_CISCO_GET_IPADDR
   This command returns the IP configuration in the same format used by
   .Dv NGM_CISCO_SET_IPADDR .
   This command is also
   .Em sent
   by this node type to the
   .Dv inet
   peer whenever an IP address inquiry packet is received.
   .It Dv NGM_CISCO_GET_STATUS
   Returns a
   .Dv "struct ngciscostat" :
   .Bd -literal -offset 4n
   struct ngciscostat {
     u_int32_t   seq_retries;       /* # unack'd retries */
     u_int32_t   keepalive_period;  /* in seconds */
   };
   .Ed
   .El
   .Sh SHUTDOWN
   This node shuts down upon receipt of a
   .Dv NGM_SHUTDOWN
   control message, or when all hooks have been disconnected.
   .Sh BUGS
   Not all of the functionality has been implemented. For example,
   the node does not support querying the remote end for its IP address
   and netmask.
   .Sh SEE ALSO
   .Xr netgraph 4 ,
   .Xr ng_iface 4 ,
   .Xr ngctl 8
   .Rs
   .%A D. Perkins
   .%T "Requirements for an Internet Standard Point-to-Point Protocol"
   .%O RFC 1547
   .Re
   .Sh LEGAL
   .Tn Cisco
   is a trademark of Cisco Systems, Inc.
   .Sh HISTORY
   The
   .Nm
   node type was implemented in
   .Fx 4.0 .
   .Sh AUTHORS
   .An Julian Elischer Aq julian@freebsd.org ,
   .An Archie Cobbs Aq archie@freebsd.org

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