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Command: ns | Section: 4 | Source: 4.4BSD | File: ns.4
NS(4) FreeBSD Kernel Interfaces Manual NS(4)
NAME
ns - Xerox Network Systems(tm) protocol family
SYNOPSIS
options NS
options NSIP
pseudo-device ns
DESCRIPTION
The NS protocol family is a collection of protocols layered atop the
Internet Datagram Protocol (IDP) transport layer, and using the Xerox NS
address formats. The NS family provides protocol support for the
SOCK_STREAM, SOCK_DGRAM, SOCK_SEQPACKET, and SOCK_RAW socket types; the
SOCK_RAW interface is a debugging tool, allowing you to trace all packets
entering, (or with toggling kernel variable, additionally leaving) the
local host.
ADDRESSING
NS addresses are 12 byte quantities, consisting of a 4 byte Network
number, a 6 byte Host number and a 2 byte port number, all stored in
network standard format. (on the VAX these are word and byte reversed;
on the Sun they are not reversed). The include file <netns/ns.h> defines
the NS address as a structure containing unions (for quicker
comparisons).
Sockets in the Internet protocol family use the following addressing
structure:
struct sockaddr_ns {
short sns_family;
struct ns_addr sns_addr;
char sns_zero[2];
};
where an ns_addr is composed as follows:
union ns_host {
u_char c_host[6];
u_short s_host[3];
};
union ns_net {
u_char c_net[4];
u_short s_net[2];
};
struct ns_addr {
union ns_net x_net;
union ns_host x_host;
u_short x_port;
};
Sockets may be created with an address of all zeroes to effect "wildcard"
matching on incoming messages. The local port address specified in a
bind(2) call is restricted to be greater than NSPORT_RESERVED (=3000, in
<netns/ns.h>) unless the creating process is running as the super-user,
providing a space of protected port numbers.
PROTOCOLS
The NS protocol family supported by the operating system is comprised of
the Internet Datagram Protocol (IDP) idp(4), Error Protocol (available
through IDP), and Sequenced Packet Protocol (SPP) spp(4).
SPP is used to support the SOCK_STREAM and SOCK_SEQPACKET abstraction,
while IDP is used to support the SOCK_DGRAM abstraction. The Error
protocol is responded to by the kernel to handle and report errors in
protocol processing; it is, however, only accessible to user programs
through heroic actions.
SEE ALSO
intro(3), byteorder(3), gethostbyname(3), getnetent(3), getprotoent(3),
getservent(3), ns(3), intro(4), spp(4), idp(4), nsip(4)
Internet Transport Protocols, Xerox Corporation document XSIS, 028112.
An Advanced 4.3 BSD Interprocess Communication Tutorial.
HISTORY
The ns protocol family appeared in 4.3BSD.
BSD 4.3 March 28, 1991 BSD 4.3