.\" .\" =================================== .\" HARP | Host ATM Research Platform .\" =================================== .\" .\" .\" This Host ATM Research Platform ("HARP") file (the "Software") is .\" made available by Network Computing Services, Inc. ("NetworkCS") .\" "AS IS". NetworkCS does not provide maintenance, improvements or .\" support of any kind. .\" .\" NETWORKCS MAKES NO WARRANTIES OR REPRESENTATIONS, EXPRESS OR IMPLIED, .\" INCLUDING, BUT NOT LIMITED TO, IMPLIED WARRANTIES OF MERCHANTABILITY .\" AND FITNESS FOR A PARTICULAR PURPOSE, AS TO ANY ELEMENT OF THE .\" SOFTWARE OR ANY SUPPORT PROVIDED IN CONNECTION WITH THIS SOFTWARE. .\" In no event shall NetworkCS be responsible for any damages, including .\" but not limited to consequential damages, arising from or relating to .\" any use of the Software or related support. .\" .\" Copyright 1994-1998 Network Computing Services, Inc. .\" .\" Copies of this Software may be made, however, the above copyright .\" notice must be reproduced on all copies. .\" .\" @(#) $FreeBSD$ .\" .\" .Dd August 21, 1998 .Dt SCSPD 8 .Os .Sh NAME .Nm scspd .Nd "SCSP daemon" .Sh SYNOPSIS .Nm .Op Fl f Aq Ar cfg\-file .Op Fl d .Op Fl T Ns Aq Ar options .Sh DESCRIPTION .Nm Scspd is an implementation of the Server Cache Synchronization Protocol (SCSP) for the Host ATM Research Platform (HARP) networking software. .Nm Scspd synchronizes the cache(s) of server(s) running on a host with the caches of servers on remote hosts. SCSP is defined for a number of different protocols, but the present version of .Nm only supports ATMARP. .Pp By using .Nm and .Xr atmarpd 8 , one can provide multiple ATMARP servers in a single ATM LIS. This might be useful, for example, when a LIS consists of a number of local-area ATM networks connected by long-distance links. Each local-area network could have its own ATMARP server, with all the servers' caches being synchronized by SCSP. Then, if a long-distance link fails, hosts on a local-area network will still have connectivity to other local hosts (since they all use the local ATMARP server); when the long-distance link is restored, SCSP will re-synchronize the servers' caches, restoring connectivity to remote hosts. Both .Nm and .Xr atmarpd 8 must be running before any ATMARP cache synchronization can take place. .Pp .Nm Scspd implements SCSP as specified in RFC 2334, .%T "Server Cache Synchronization Protocol (SCSP)" and .Pa draft\-ietf\-ion\-scspd\-atmarpd\-00.txt , .%T "A Distributed ATMARP Service using SCSP" . .Pp When .Nm starts, it parses its command line and puts itself into the background. .Sh TERMINOLOGY Some of the vocabulary associated with SCSP can be confusing. In this document, the following definitions are used: .Pp .Em "Client server" or .Em "local server" means the server running on the same host as .Nm whose cache is to be synchronized with that of one or more remote servers. When the word .Em server is used alone, it means .Em "client server" . .Pp .Em "Remote server" means a server running on some host other than the one where .Nm is running. .Pp .Em "Directly Connected Server" (DCS) means a remote server that .Nm communicates with directly. The remote server will also be running an implementation of SCSP. .Pp .Em "Cache Alignment" (CA) has two meanings. The Cache Alignment protocol is a part of the SCSP protocol specification, and the Cache Alignment finite state machine (FSM) is a finite state machine that implements the Cache Alignment protocol. .Sh OPTIONS The command-line options are: .Bl -tag -width "-f " .It Fl f Aq Ar cfg\-file Specifies the name of the configuration file. If this option is not specified, .Nm looks for the file .Pa /etc/scspd.conf . .It Fl d Specifies that .Nm is to be run in debug mode. In debug mode, the daemon is not put into the background. Log messages are written to standard output instead of to the log file specified in the configuration file. .It Fl T Ns Aq Ar options Specifies that .Nm will trace specified events and messages as it executes. The .Fl T flag is followed by one or more of the following options: .Pp .Bl -tag -width 4n -compact .It Cm c trace .Nm Ns 's CA Finite State Machine (FSM), .It Cm h trace .Nm Ns 's Hello FSM, .It Cm i trace .Nm Ns 's Client Interface FSM, .It Cm C trace CA, CSUS, CSU Request, and CSU Reply messages, .It Cm H trace Hello messages, .It Cm I trace interface messages to and from .Nm Ns 's clients. .El .El .Sh CONFIGURATION The configuration file consists of a sequence of configuration statements. These statements specify information about the servers, both local and remote, whose caches are to be synchronized by .Nm . RFC 2334, .%T "Server Cache Synchronization Protocol (SCSP)" and .Pa draft\-ietf\-ion\-scspd\-atmarpd\-00.txt , .%T "A Distributed ATMARP Service using SCSP" will be valuable in understanding how to configure .Nm . .Pp A configuration statement other than a comment is terminated by a semicolon. Some statements contain blocks, delimited by braces .No ( Dq Li { and .Dq Li } ) . Configuration statement keywords are not case-sensitive, but some parameters (e.g. interface names) are. Configuration statements can span multiple lines. .Ss Comments Three types of comments are allowed: .Bl -hang .It Sy "# comments" : any characters from .Dq Li # to the end of the line are ignored. .It Sy "C comments" : any characters between .Dq Li /* and .Dq Li */ are ignored. .It Sy "C++ comments" : any characters from .Dq Li // to the end of the line are ignored. .El .Ss Statements The configuration statements recognized by .Nm are: .Bd -literal Server { Protocol ; Netif ; ServerGroupID ; FamilyID ; DCS { ATMaddr ; ID ; CAReXmitInt ; CSUSReXmitInt ; CSUReXmitInt ; CSUReXmitMax ; HelloDead ; HelloInt ; Hops ; }; }; Log { File ; Syslog; }; .Ed .Pp Where a host address needs to be specified in the configuration file, either a DNS name or an IP address in dotted decimal format can be used. .Pp ATM addresses are specified as strings of hex digits, with an optional leading .Dq Li 0x . Fields within the address may be separated by periods, but periods are for readability only and are ignored. ATM addresses are 20 bytes long. The full address, including any leading zeroes, must be given. For example: .Pp .Dl "0x47.0005.80.ffe100.0000.f21a.0170.0020481a0170.00" .Ss "Server Statement" The .Ic server statement specifies a client server whose cache to be synchronized with the caches of other servers running on remote hosts. There will be one .Ic server statement in the configuration file for each client server whose cache is to be synchronized by .Nm . The format of the .Ic server statement is: .Bd -ragged -offset indent .Ic Server .Aq Ar name { .Aq Ar statements }; .Ed .Pp A .Ar name must be specified on the .Ic server statement, but it is not used by .Nm . It is expected to give a brief description of the server's purpose. .Pp The .Ic server statement has several sub-statements that specify the details of the .Nm Ns 's configuration. They are: .Bl -tag -width indent .It Ic Protocol Cm ATMARP ; The only protocol supported by the current version of .Nm is .Cm ATMARP . The .Ic protocol statement must always be specified. .It Ic Netif Aq Ar intf ; The .Ic netif statement specifies the name of the ATM network interface on which a client server is providing service. The .Ic netif statement must always be specified. .It Ic ServerGroupID Aq Ar ID ; The .Ic ServerGroupID statement specifies an identifier for the group of servers being synchronized by .Nm . The .Ar ID is specified as a decimal number in the range 0 - 65,535. The server group ID must be the same for all servers whose caches are being synchronized by an SCSP session. That is, the server group ID for a host must be the same for all Directly Connected Servers (DCSs) pointed to within a .Ic server statement. The .Ic ServerGroupID statement must always be specified. .It Ic FamilyID Aq Ar ID ; The .Ic familyID statement specifies an identifier for a family of parallel SCSP sessions running between a group of hosts (i.e. a set of SCSP sessions with different protocol IDs but the same set of servers). The .Ar ID is specified as a decimal number in the range 0 - 65,535. The family ID is currently not used by .Nm . .El .Ss "DCS Statement" The .Ic DCS statement is a sub-statement of the .Ic server statement that specifies the characteristics of a Directly Connected Server (DCS). The .Ic server statement will have one .Ic DCS statement for each DCS that .Nm is to exchange information with. The .Ic DCS statement has a number of sub-statements that specify the details of the configuration for the DCS. They are: .Bl -tag -width indent .It Ic ATMaddr Aq Ar ATM\ address ; The .Ic ATMaddr statement specifies the ATM address of the DCS. The .Ic ATMaddr statement must always be specified. .It Ic ID Aq Ar host ; The .Ic ID statement specifies the SCSP identifier of the DCS. For ATMARP, the ID is the IP address or DNS name associated with the ATM interface of the DCS. The .Ic ID statement must always be specified. .It Ic CAReXmitInt Aq Ar int ; The .Ic CAReXmitInt statement specifies the interval that is allowed to elapse between retransmissions of CA messages. If a CA message is sent and an acknowledgement is not received within .Ic CAReXmitInt seconds, the message will be retransmitted. The default value for .Ic CAReXmitInt is 3 seconds. .It Ic CSUSReXmitInt Aq Ar int ; The .Ic CSUSReXmitInt statement specifies the interval that is allowed to elapse between retransmissions of CSU Solicit messages. When a CSUS message is sent, any Cache State Advertisements (CSAs) requested by the CSUS that have not been received within .Ic CSUSReXmitInt seconds will be requested again by another CSUS message. The default value for .Ic CSUSReXmitInt is 3 seconds. Be careful not to confuse .Ic CSUSReXmitInt and .Ic CSUReXmitInt . .It Ic CSUReXmitInt Aq Ar int ; The .Ic CSUReXmitInt statement specifies the interval that is allowed to elapse between retransmissions of CSU Request messages. When a CSU Request message is sent, any CSAs that are not acknowledged by a CSU Reply message within .Ic CSUReXmitInt seconds will be retransmitted. The default value for .Ic CSUReXmitInt is 2 seconds. Be careful not to confuse .Ic CSUReXmitInt and .Ic CSUSReXmitInt . .It Ic CSUReXmitMax Aq Ar cnt ; The .Ic CSUReXmitMax statement specifies the number of times that a CSA will be retransmitted as described above before SCSP gives up on the CSA and discards it. The default value for .Ic CSUReXmitMax is 5. .It Ic HelloDead Aq Ar cnt ; The .Ic HelloDead statement specifies the Hello Dead Factor that will be sent to the DCS in Hello messages. A .Dq "DCS down" condition will be detected when nothing is received from a DCS in .Ic HelloDead No * Ic HelloInt seconds. The default value for .Ic HelloDead is 3. .It Ic HelloInt Aq Ar int ; The .Ic HelloInt statement specifies the Hello Interval that will be sent to the DCS in Hello messages. The default value for .Ic HelloInt is 3 seconds. .It Ic Hops Aq Ar cnt ; The .Ic Hops statement specifies the number of hops (DCS to DCS) that will be specified in CSAs originating from the local server. This number must be at least as large as the diameter of the server group. That is, it must be large enough for a CSA to be propagated from server to server all the way across the server group. The default value for .Ic Hops is 3. .El .Ss "Log Statement" The .Ic log statement specifies how .Nm is to log information about its operation. .Nm Scspd can write log information to a file, to the system log, or both. .Bl -tag -width indent .It Ic File Aq Ar file\ name ; The .Ic file statement specifies that .Nm is to write its log messages to the named file. Log messages will be appended to the end of the file if it already exists. .It Ic Syslog ; The .Ic syslog statement specifies that .Nm is to write its log messages to the syslog facility. .Nm Scspd writes its messages to syslog with a facility code of .Dv LOG_DAEMON . .El .Pp If no .Ic log statement is specified, .Nm writes log messages to the system log. If both .Ic file and .Ic syslog are specified, .Nm will write log messages to both the named file and the system log. .Ss Examples An example of a simple configuration file for .Nm might be: .Bd -literal -offset indent server atmarp_ni0 { protocol ATMARP; netif ni0; ServerGroupID 23; DCS { ID 10.1.1.2; ATMaddr 0x47.0005.80.ffdc00.0000.0002.0001.002048061de7.00; hops 2; }; }; .Ed .Pp This configuration would synchronize the cache of the ATMARP server operating on network interface ni0 with the cache of a second server running on a host whose IP address is 10.1.1.2. Log messages would be written to the system log. .Sh SIGNAL PROCESSING The following signals can be used to control .Nm : .Bl -tag -width indent .It Dv SIGHUP Reread the configuration file and restart .Nm . .It Dv SIGINT Dump debugging information to a file. When it receives a .Dv SIGINT signal, .Nm dumps a summary of its control blocks to a text file (see .Sx FILES ) . .El .Sh FILES .Bl -tag -width indent .It Pa /etc/scspd.conf .Nm Scspd default configuration file name. A different file name can be specified with the .Fl f command-line option. .It Xo .Sm off .Pa /tmp/scspd. .Aq Ar pid .Pa \&. .Aq Ar seq .Pa .out .Sm on .Xc Debugging information dump file name. .Nm Scspd writes a summary of its control blocks to this file when it receives a .Dv SIGINT signal. .Aq Ar pid is the process ID of the daemon and .Aq Ar seq is a sequence number which is incremented every time a dump is taken. .It Xo .Sm off .Pa /tmp/scspd. .Aq Ar pid .Pa .trace .Sm on .Xc Trace file. .Nm Scspd writes trace information to this file if the .Fl T option is specified on the command line. .El .Sh SEE ALSO .Xr atm 8 , .Xr atmarpd 8 .Rs .%O "RFC 2334" .%T "Server Cache Synchronization Protocol (SCSP)" .Re .Rs .%O "draft\-ietf\-ion\-scsp\-atmarpd\-00.txt" .%T "A Distributed ATMARP Service Using SCSP" .Re .Sh BUGS If .Nm terminates and is restarted, there will be a period of instability while previously-synchronized cache entries time out and are refreshed. .Pp Please report any bugs to .Aq harp\-bugs@magic.net . .Sh COPYRIGHT Copyright (c) 1994-1998, Network Computing Services, Inc. .Sh AUTHORS .An John Cavanaugh , Network Computing Services, Inc. .An Mike Spengler , Network Computing Services, Inc. .An Joe Thomas , Network Computing Services, Inc. .Sh ACKNOWLEDGMENTS This software was developed with the support of the Defense Advanced Research Projects Agency (DARPA).