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ns(4f) [bsd man page]

NS(4F)																	    NS(4F)

ns - Xerox Network Systems(tm) protocol family SYNOPSIS
Not currently supported under 2.11BSD 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 speci- fied 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(4P), Error Protocol (available through IDP), and Sequenced Packet Protocol (SPP) spp(4P). 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(3N), gethostbyname(3N), getnetent(3N), getprotoent(3N), getservent(3N), ns(3N), intro(4N), spp(4P), idp(4P), nsip(4) Internet Transport Protocols, Xerox Corporation document XSIS-028112 An Advanced 4.3BSD Interprocess Communication Tutorial 3rd Berkeley Distribution January 27, 1996 NS(4F)

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SPP(4P) 																   SPP(4P)

spp - Xerox Sequenced Packet Protocol SYNOPSIS
#include <sys/socket.h> #include <netns/ns.h> s = socket(AF_NS, SOCK_STREAM, 0); #include <netns/sp.h> s = socket(AF_NS, SOCK_SEQPACKET, 0); DESCRIPTION
The SPP protocol provides reliable, flow-controlled, two-way transmission of data. It is a byte-stream protocol used to support the SOCK_STREAM abstraction. SPP uses the standard NS(tm) address formats. Sockets utilizing the SPP protocol are either "active" or "passive". Active sockets initiate connections to passive sockets. By default SPP sockets are created active; to create a passive socket the listen(2) system call must be used after binding the socket with the bind(2) system call. Only passive sockets may use the accept(2) call to accept incoming connections. Only active sockets may use the connect(2) call to initiate connections. Passive sockets may "underspecify" their location to match incoming connection requests from multiple networks. This technique, termed "wildcard addressing", allows a single server to provide service to clients on multiple networks. To create a socket which listens on all networks, the NS address of all zeroes must be bound. The SPP port may still be specified at this time; if the port is not specified the system will assign one. Once a connection has been established the socket's address is fixed by the peer entity's location. The address assigned the socket is the address associated with the network interface through which packets are being transmitted and received. Nor- mally this address corresponds to the peer entity's network. If the SOCK_SEQPACKET socket type is specified, each packet received has the actual 12 byte sequenced packet header left for the user to inspect: struct sphdr { u_char sp_cc; /* connection control */ #define SP_EM 0x10 /* end of message */ u_char sp_dt; /* datastream type */ u_short sp_sid; u_short sp_did; u_short sp_seq; u_short sp_ack; u_short sp_alo; }; This facilitates the implementation of higher level Xerox protocols which make use of the data stream type field and the end of message bit. Conversely, the user is required to supply a 12 byte header, the only part of which inspected is the data stream type and end of mes- sage fields. For either socket type, packets received with the Attention bit sent are interpreted as out of band data. Data sent with send(..., ..., ..., MSG_OOB) cause the attention bit to be set. DIAGNOSTICS
A socket operation may fail with one of the following errors returned: [EISCONN] when trying to establish a connection on a socket which already has one; [ENOBUFS] when the system runs out of memory for an internal data structure; [ETIMEDOUT] when a connection was dropped due to excessive retransmissions; [ECONNRESET] when the remote peer forces the connection to be closed; [ECONNREFUSED] when the remote peer actively refuses connection establishment (usually because no process is listening to the port); [EADDRINUSE] when an attempt is made to create a socket with a port which has already been allocated; [EADDRNOTAVAIL] when an attempt is made to create a socket with a network address for which no network interface exists. SOCKET OPTIONS
SO_DEFAULT_HEADERS when set, this determines the data stream type and whether the end of message bit is to be set on every ensuing packet. SO_MTU This specifies the maximum ammount of user data in a single packet. The default is 576 bytes - sizeof(struct spidp). This quantity affects windowing -- increasing it without increasing the amount of buffering in the socket will lower the number of unread packets accepted. Anything larger than the default will not be forwarded by a bona fide XEROX product internetwork router. The data argument for the setsockopt call must be an unsigned short. SEE ALSO
intro(4N), ns(4F) BUGS
There should be some way to reflect record boundaries in a stream. For stream mode, there should be an option to get the data stream type of the record the user process is about to receive. 4.3 Berkeley Distribution July 30, 1985 SPP(4P)
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