diff options
Diffstat (limited to 'share/man/man4/ng_sscop.4')
| -rw-r--r-- | share/man/man4/ng_sscop.4 | 403 |
1 files changed, 403 insertions, 0 deletions
diff --git a/share/man/man4/ng_sscop.4 b/share/man/man4/ng_sscop.4 new file mode 100644 index 000000000000..0c6f0d4564b9 --- /dev/null +++ b/share/man/man4/ng_sscop.4 @@ -0,0 +1,403 @@ +.\" +.\" Copyright (c) 2001-2003 +.\" Fraunhofer Institute for Open Communication Systems (FhG Fokus). +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" Author: Hartmut Brandt <harti@FreeBSD.org> +.\" +.\" $FreeBSD$ +.\" +.\" ng_sscop(4) man page +.\" +.Dd October 24, 2003 +.Dt NG_SSCOP 4 +.Os +.Sh NAME +.Nm ng_sscop +.Nd netgraph SSCOP node type +.Sh SYNOPSIS +.In netnatm/saal/sscopdef.h +.In netgraph/atm/ng_sscop.h +.Sh DESCRIPTION +The +.Nm sscop +netgraph node type implements the ITU-T standard Q.2110. +This standard describes +the so called Service Specific Connection Oriented Protocol (SSCOP) that +is used to carry signalling messages over the private and public UNIs and +the public NNI. +This protocol is a transport protocol with selective +acknowledgements, and can be tailored to the environment. +This implementation is a full implementation of that standard. +.Pp +After creation of the node, the SSCOP instance must be created by sending +an +.Dq enable +message to the node. +If the node is enabled, the SSCOP parameters +can be retrieved and modified and the protocol can be started. +.Pp +The node is shut down either by a +.Dv NGM_SHUTDOWN +message, or when all hooks are disconnected. +.Sh HOOKS +Each +.Nm sscop +node has three hooks with fixed names: +.Bl -tag -width ".Va manage" +.It Va lower +This hook must be connected to a node that ensures +transport of packets to and from the remote peer node. +Normally this is a +.Xr ng_atm 4 +node with an AAL5 hook, but the +.Nm sscop +node is able to work on any packet-transporting layer, like, for example, +IP or UDP. +The node handles flow control messages received on +this hook: if it receives a +.Dv NGM_HIGH_WATER_PASSED +message, it declares the +.Dq "lower layer busy" +state. +If a +.Dv NGM_LOW_WATER_PASSED +message is received, the busy state is cleared. +Note that the node does not +look at the message contents of these flow control messages. +.It Va upper +This is the interface to the SSCOP user. +This interface uses the following message format: +.Bd -literal +struct sscop_arg { + uint32_t sig; + uint32_t arg; /* opt. sequence number or clear-buff */ + u_char data[]; +}; +.Ed +.Pp +The +.Va sig +field +is one of the signals defined in the standard: +.Bd -literal +enum sscop_aasig { + SSCOP_ESTABLISH_request, /* <- UU, BR */ + SSCOP_ESTABLISH_indication, /* -> UU */ + SSCOP_ESTABLISH_response, /* <- UU, BR */ + SSCOP_ESTABLISH_confirm, /* -> UU */ + + SSCOP_RELEASE_request, /* <- UU */ + SSCOP_RELEASE_indication, /* -> UU, SRC */ + SSCOP_RELEASE_confirm, /* -> */ + + SSCOP_DATA_request, /* <- MU */ + SSCOP_DATA_indication, /* -> MU, SN */ + + SSCOP_UDATA_request, /* <- MU */ + SSCOP_UDATA_indication, /* -> MU */ + + SSCOP_RECOVER_indication, /* -> */ + SSCOP_RECOVER_response, /* <- */ + + SSCOP_RESYNC_request, /* <- UU */ + SSCOP_RESYNC_indication, /* -> UU */ + SSCOP_RESYNC_response, /* <- */ + SSCOP_RESYNC_confirm, /* -> */ + + SSCOP_RETRIEVE_request, /* <- RN */ + SSCOP_RETRIEVE_indication, /* -> MU */ + SSCOP_RETRIEVE_COMPL_indication,/* -> */ +}; +.Ed +.Pp +The arrows in the comment show the direction of the signal, whether it +is a signal that comes out of the node +.Pq Ql -> , +or is sent by the node user to the node +.Pq Ql <- . +The +.Va arg +field contains the argument to some of the signals: it is either a PDU +sequence number, or the +.Dv CLEAR-BUFFER +flag. +There are a number of special sequence numbers for some operations: +.Pp +.Bl -tag -width ".Dv SSCOP_RETRIEVE_UNKNOWN" -offset indent -compact +.It Dv SSCOP_MAXSEQNO +maximum legal sequence number +.It Dv SSCOP_RETRIEVE_UNKNOWN +retrieve transmission queue +.It Dv SSCOP_RETRIEVE_TOTAL +retrieve transmission buffer and queue +.El +.Pp +For signals that carry user data (as, for example, +.Dv SSCOP_DATA_request ) +these two fields are followed by the variable sized user data. +.Pp +If the +.Va upper +hook is disconnected and the SSCOP instance is not in the idle +state, and the +.Va lower +hook is still connected, an +.Dv SSCOP_RELEASE_request +is executed to release the SSCOP connection. +.It Va manage +This is the management interface defined in the standard. +The data structure used here is: +.Bd -literal +struct sscop_marg { + uint32_t sig; + u_char data[]; +}; +.Ed +.Pp +Here +.Va sig +is one of +.Bd -literal +enum sscop_maasig { + SSCOP_MDATA_request, /* <- MU */ + SSCOP_MDATA_indication, /* -> MU */ + SSCOP_MERROR_indication, /* -> CODE, CNT */ +}; +.Ed +.Pp +The +.Dv SSCOP_MDATA +signals are followed by the actual management data, where the +.Dv SSCOP_MERROR +signal has the form: +.Bd -literal +struct sscop_merr { + uint32_t sig; + uint32_t err; /* error code */ + uint32_t cnt; /* error count */ +}; +.Ed +.El +.Sh CONTROL MESSAGES +The +.Nm sscop +node understands the generic control messages, plus the following: +.Bl -tag -width indent +.It Dv NGM_SSCOP_SETPARAM +Sets operational parameters of the SSCOP instance and takes the +following structure: +.Bd -literal +struct ng_sscop_setparam { + uint32_t mask; + struct sscop_param param; +}; +.Ed +.Pp +The sub-structure +.Va param +contains the parameters to set, and the +.Va mask +field contains a bit mask, telling which of the parameters to set, and which +to ignore. +If a bit is set, the corresponding parameter is set. +The parameters are: +.Bd -literal +struct sscop_param { + uint32_t timer_cc; /* timer_cc in msec */ + uint32_t timer_poll; /* timer_poll im msec */ + uint32_t timer_keep_alive;/* timer_keep_alive in msec */ + uint32_t timer_no_response;/*timer_no_response in msec */ + uint32_t timer_idle; /* timer_idle in msec */ + uint32_t maxk; /* maximum user data in bytes */ + uint32_t maxj; /* maximum u-u info in bytes */ + uint32_t maxcc; /* max. retransmissions for control packets */ + uint32_t maxpd; /* max. vt(pd) before sending poll */ + uint32_t maxstat; /* max. number of elements in stat list */ + uint32_t mr; /* initial window */ + uint32_t flags; /* flags */ +}; +.Ed +.Pp +The +.Va flags +field contains the following flags influencing SSCOP operation: +.Pp +.Bl -tag -width ".Dv SSCOP_POLLREX" -offset indent -compact +.It Dv SSCOP_ROBUST +enable atmf/97-0216 robustness enhancement +.It Dv SSCOP_POLLREX +send POLL after each retransmission +.El +.Pp +The bitmap has the following bits: +.Pp +.Bl -tag -width ".Dv SSCOP_SET_POLLREX" -offset indent -compact +.It Dv SSCOP_SET_TCC +set +.Va timer_cc +.It Dv SSCOP_SET_TPOLL +set +.Va timer_poll +.It Dv SSCOP_SET_TKA +set +.Va timer_keep_alive +.It Dv SSCOP_SET_TNR +set +.Va timer_no_response +.It Dv SSCOP_SET_TIDLE +set +.Va timer_idle +.It Dv SSCOP_SET_MAXK +set +.Va maxk +.It Dv SSCOP_SET_MAXJ +set +.Va maxj +.It Dv SSCOP_SET_MAXCC +set +.Va maxcc +.It Dv SSCOP_SET_MAXPD +set +.Va maxpd +.It Dv SSCOP_SET_MAXSTAT +set +.Va maxstat +.It Dv SSCOP_SET_MR +set the initial window +.It Dv SSCOP_SET_ROBUST +set or clear +.Dv SSCOP_ROBUST +.It Dv SSCOP_SET_POLLREX +set or clear +.Dv SSCOP_POLLREX +.El +.Pp +The node responds to the +.Dv NGM_SSCOP_SETPARAM +message with the following response: +.Bd -literal +struct ng_sscop_setparam_resp { + uint32_t mask; + int32_t error; +}; +.Ed +.Pp +Here +.Va mask +contains a bitmask of the parameters that the user requested to set, +but that could not be set and +.Va error +is an +.Xr errno 2 +code describing why the parameter could not be set. +.It Dv NGM_SSCOP_GETPARAM +This message returns the current operational parameters of the SSCOP +instance in a +.Vt sscop_param +structure. +.It Dv NGM_SSCOP_ENABLE +This message creates the actual SSCOP instance and initializes it. +Until this is done, parameters may neither be retrieved nor set, and all +messages received on any hook are discarded. +.It Dv NGM_SSCOP_DISABLE +Destroy the SSCOP instance. +After this, all messages on any hooks are +discarded. +.It Dv NGM_SSCOP_SETDEBUG +Set debugging flags. +The argument is a +.Vt uint32_t . +.It Dv NGM_SSCOP_GETDEBUG +Retrieve the actual debugging flags. +Needs no arguments and responds with a +.Vt uint32_t . +.It Dv NGM_SSCOP_GETSTATE +Responds with the current state of the SSCOP instance in a +.Vt uint32_t . +If the node is not enabled, the retrieved state is 0. +.El +.Sh FLOW CONTROL +Flow control works on the upper and on the lower layer interface. +At the lower +layer interface, the two messages, +.Dv NGM_HIGH_WATER_PASSED +and +.Dv NGM_LOW_WATER_PASSED , +are used to declare or clear the +.Dq "lower layer busy" +state of the protocol. +.Pp +At the upper layer interface, the +.Nm sscop +node handles three types of flow control messages: +.Bl -tag -width indent +.It Dv NGM_HIGH_WATER_PASSED +If this message is received, the SSCOP stops moving the receive window. +Each time a data message is handed over to the upper layer, the receive +window is moved by one message. +Stopping these updates +means that the window will start to close and if the peer has sent +all messages allowed by the current window, it stops transmission. +This means that the upper layer must be able to still receive a full window +amount of messages. +.It Dv NGM_LOW_WATER_PASSED +This will re-enable the automatic window updates, and if the space indicated +in the message is larger than the current window, the window will be opened +by that amount. +The space is computed as the difference of the +.Va max_queuelen_packets +and +.Va current +members of the +.Vt ngm_queue_state +structure. +.It Dv NGM_SYNC_QUEUE_STATE +If the upper layer buffer filling state, as indicated by +.Va current , +is equal to or greater than +.Va high_watermark +then the message is ignored. +If this is not the case, the amount +of receiver space is computed as the difference of +.Va max_queuelen_packets +and +.Va current +if automatic window updates are currently allowed, and as the difference of +.Va high_water_mark +and +.Va current +if window updates are disabled. +If the resulting value is larger than the current window, the current window +is opened up to this value. +Automatic window updates are enabled if they +were disabled. +.El +.Sh SEE ALSO +.Xr netgraph 4 , +.Xr ng_atm 4 , +.Xr ng_sscfu 4 , +.Xr ngctl 8 +.Sh AUTHORS +.An Harti Brandt Aq harti@FreeBSD.org |