sdp(7D) Devices sdp(7D)NAMEsdp - 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 implemen‐
tation 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 pro‐
grams. It also supports graceful close (including half-closed sockets),
IP addressing (IPv4 or IPv6), the connecting/accepting connect model,
out-of-band (OOB) data and common socket options. The SDP protocol also
supports kernel bypass data transfers and data transfers from send-
upper-layer-protocol (ULP) buffers to receive ULP buffers. A SDP mes‐
sage 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 func‐
tion 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 ini‐
tiate 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 lis‐
ten(3SOCKET) system call after binding the socket with bind(). This
process establishes a queueing parameter for the passive socket. Con‐
nections 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 sup‐
plies 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 SIOCATMARK
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 opera‐
tion. 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_OOBIN‐
LINE.
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 ALSOread(2), getsockopt(3XNET), socket.h(3HEAD), accept(3SOCKET),
bind(3SOCKET), connect(3SOCKET), send(3SOCKET), attributes(5), stan‐
dards(5)
Infiniband Architecture Specification Vol 1- Annex 4 — November, 2002
SunOS 5.10 13 Nov 2006 sdp(7D)
