NAME

       ng_cisco — Cisco HDLC protocol netgraph node type

SYNOPSIS

       #include <sys/types.h>
       #include <netinet/in.h>
       #include <netgraph/ng_cisco.h>

DESCRIPTION

       The 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 “keep alive” and an
       “inquire” capability.

       The downstream hook should connect to the synchronous line.  On the other side of the node are the  inet,
       inet6,  atalk,  and  ipx  hooks,  which  transmit  and  receive raw IP, IPv6, AppleTalk, and IPX packets,
       respectively.  Typically these hooks would connect to the corresponding  hooks  on  an  ng_iface(4)  type
       node.

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 “inquire” packet which we must be prepared  to
       answer.  There are two ways to accomplish this, manually and automatically.

       Whenever such an inquire packet is received, the node sends a NGM_CISCO_GET_IPADDR control message to the
       peer  node  connected to the inet hook (if any).  If the peer responds, then that response is used.  This
       is the automatic method.

       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 NGM_CISCO_SET_IPADDR message, and this is the manual
       method.

       If the inet hook is connected to the inet hook of an ng_iface(4) node,  as  is  usually  the  case,  then
       configuration is automatic as the ng_iface(4) understands the NGM_CISCO_GET_IPADDR message.

HOOKS

       This node type supports the following hooks:

       downstream  The connection to the synchronous line.

       inet        IP hook.

       inet6       IPv6 hook.

       atalk       AppleTalk hook.

       ipx         IPX hook.

CONTROL MESSAGES

       This node type supports the generic control messages, plus the following:

       NGM_CISCO_SET_IPADDR (setipaddr)
            This  command  takes  an  array of two struct in_addr arguments.  The first is the IP address of the
            corresponding interface and the second is the netmask.

       NGM_CISCO_GET_IPADDR (getipaddr)
            This command returns the IP configuration in the same format  used  by  NGM_CISCO_SET_IPADDR.   This
            command  is  also  sent  by this node type to the inet peer whenever an IP address inquiry packet is
            received.

       NGM_CISCO_GET_STATUS (getstats)
            Returns a struct ngciscostat:

                struct ngciscostat {
                  uint32_t   seqRetries;        /* # unack'd retries */
                  uint32_t   keepAlivePeriod;   /* in seconds */
                };

SHUTDOWN

       This node shuts down upon receipt of a  NGM_SHUTDOWN  control  message,  or  when  all  hooks  have  been
       disconnected.

SEE ALSO

       netgraph(4), ng_iface(4), ngctl(8)

       D. Perkins, Requirements for an Internet Standard Point-to-Point Protocol, RFC 1547.

LEGAL

       Cisco is a trademark of Cisco Systems, Inc.

HISTORY

       The ng_cisco node type was implemented in FreeBSD 4.0.

AUTHORS

       Julian Elischer <julian@FreeBSD.org>
       Archie Cobbs <archie@FreeBSD.org>

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.

Debian                                          January 19, 1999                                     NG_CISCO(4)