urgent

sdp(7D) 							      Devices								   sdp(7D)

NAME

       sdp - Sockets Direct Protocol driver

SYNOPSIS

       #include <socket.h>

       #include <netinet/in.h>

       s = socket(AF_INET, SOCK_STREAM, PROTO_SDP);

       s = socket(AF_INET6, SOCK_STREAM, PROTO_SDP);

DESCRIPTION

       The  Sockets Direct Protocol (SDP) is a transport protocol layered over the Infiniband Transport Framework (IBTF). SDP is a standard imple-
       mentation based on Annex 4 of the Infiniband Architecture Specification Vol 1 and provides reliable byte-stream,  flow  controlled  two-way
       data transmission that closely mimics the Transmission Control Protocol (TCP).

       SDP  supports  a  sockets-based SOCK_STREAM interface to application programs. It also supports graceful close (including half-closed sock-
       ets), IP addressing (IPv4 or IPv6), the connecting/accepting connect model, out-of-band (OOB) data and common socket options. The SDP  pro-
       tocol  also supports kernel bypass data transfers and data transfers from send-upper-layer-protocol (ULP) buffers to receive ULP buffers. A
       SDP message includes a BSDH header followed by data. (A BSDH header advertises the amount of available buffers on the local side).

       SDP networking functionality is broken into the sdp driver and a function call-based  sockfs  implementation.  A  new  protocol	family	of
       PROTO_SDP is introduced to use the SDP transport provided by the driver.

       Sockets utilizing SDP are either active or passive. Active sockets initiate connections to passive sockets. Both active and passive sockets
       must have their local IP or IPv6 address and SDP port number bound with the bind(3SOCKET) system call  after  the  socket  is  created.	By
       default,  SDP  sockets  are  active.  A	passive socket is created by calling the listen(3SOCKET) system call after binding the socket with
       bind(). This process establishes a queueing parameter for the passive socket. Connections to the passive  socket can be received  with  the
       accept(3SOCKET) system call. Active sockets use the connect(3SOCKET) call after binding to initiate connections.

       In  most cases, SDP sends data when it is presented. When outstanding  data is not yet acknowledged, SDP gathers small amounts of output to
       be sent in a single  packet once an acknowledgement is received. For a small number of clients this  packetization  may	cause  significant
       delays.	To circumvent this problem,  SDP provided by the driver supplies SDP_NODELAY, a socket-level boolean option. Note that this behav-
       ior is similar to the TCP_NODELAY option.

       SDP provides an urgent data mechanism that can be invoked using the out-of-band provisions  of	send(3SOCKET).	The  out-of-band  delivery
       behavior  is  identical	to  TCP.  The  caller may mark one byte as "urgent" with the  MSG_OOB  flag to send(3SOCKET). This sets an "urgent
       pointer" pointing to the byte in the SDP stream. The receiver of the stream is notified of the urgent data by a SIGURG signal. The  SIOCAT-
       MARK   ioctl(2)	request  returns a value indicating whether the stream is at the urgent mark. Because the system never returns data across
       the urgent  mark in a single read(2) call, it is possible to advance to the urgent data in a simple loop which  reads  data,  testing   the
       socket with the SIOCATMARK  ioctl() request until it reaches the mark.

ADDRESS FORMATS

       SDP  uses  IP/IPv6  addresses to refer to local and remote devices and opens a reliable connected IB connection between two end points. The
       sdp driver supports a point-to-point connection, however broadcasting and multicasting are not supported.

SOCKET OPTIONS

       SDP supports setsockopt and getsockopt to set and read socket options. Very few socket options affect SDP protocol operations. Other common
       socket  options	are   processed  but  do  not  affect  SDP  protocol  operation. All socket options are checked for validity. A getsockopt
       returns the values set or toggled by setsockopt. Socket options that affect protocol operations are SO_LINGER, SO_DEBUG,  SO_REUSEADDR  and
       SO_OOBINLINE.

ERRORS

       EISCONN			   A connect() operation was attempted on a socket on which a connect() operation had already  been performed.

       ECONNRESET		   The	remote	peer  forced  the connection to be closed. This usually occurs when the remote machine loses state
				   information about the connection due to a crash.

       ECONNREFUSED		   The remote peer actively refused connection establishment. This usually occurs because no process is  listening
				   to the port.

       EADDRINUSE		   A  bind()  operation was attempted  on a socket with a network address/port pair that has already been bound to
				   another socket.

       EADDRNOTAVAIL		   A bind() operation was attempted on a socket with a network address for which no network interface exists.

       EACCES			   A bind() operation was attempted with  a reserved port number and the effective user ID of the process was  not
				   the privileged user.

       ENOBUFS			   The system ran out of memory for internal data structures.

FILES

       /kernel/drv/sdp

	   32-bit ELF kernel module (x86).

       /kernel/drv/amd64/sdp

	   64-bit ELF kernel module (x86).

       /kernel/drv/sparcv9/sdp

	   64-bit ELF kernel module (SPARC).

       /kernel/drv/sdpib

	   32-bit ELF kernel module (x86).

       /kernel/drv/amd64/sdpib

	   64-bit ELF kernel module (x86).

       /kernel/drv/sparcv9/sdpib

	   64-bit ELF kernel module (SPARC).

ATTRIBUTES

       See attributes(5) for descriptions of the following attribute:

       +-------------------------+---------------------------------+
       |     ATTRIBUTE TYPE	 |	   ATTRIBUTE VALUE	   |
       +-------------------------+---------------------------------+
       |Architecture		 | x86, SPARC			   |
       +-------------------------+---------------------------------+
       |Availability		 | SUNWibsdp, SUNWibsdp 	   |
       +-------------------------+---------------------------------+

SEE ALSO

       read(2), getsockopt(3XNET), socket.h(3HEAD), accept(3SOCKET), bind(3SOCKET), connect(3SOCKET), send(3SOCKET), attributes(5), standards(5)

       Infiniband Architecture Specification Vol 1- Annex 4 -- November, 2002

SunOS 5.11							    13 Nov 2006 							   sdp(7D)