| 1 | .\" Copyright (c) 1985 Regents of the University of California. |
| 2 | .\" All rights reserved. The Berkeley software License Agreement |
| 3 | .\" specifies the terms and conditions for redistribution. |
| 4 | .\" |
| 5 | .\" @(#)nsip.4 1.1 (Berkeley) %G% |
| 6 | .\" |
| 7 | .TH NSIP 4 "July 30, 1985" |
| 8 | .UC 6 |
| 9 | .SH NAME |
| 10 | nsip \- software network interface encapsulating ns packets in ip packets. |
| 11 | .SH SYNOPSIS |
| 12 | .B options NSIP |
| 13 | .br |
| 14 | .B #include <netns/ns_if.h> |
| 15 | .SH DESCRIPTION |
| 16 | The |
| 17 | .I nsip |
| 18 | interface is a software mechanism which may be |
| 19 | used to transmit Xerox NS(tm) packets through otherwise uncooperative |
| 20 | networks. |
| 21 | It functions by prepending an IP header, and resubmitting the packet |
| 22 | through the unix IP machinery. |
| 23 | .LP |
| 24 | The super-user can advise the operating system of a willing partner |
| 25 | by naming an IP address to be associated with an NS address. |
| 26 | Presently, only specific hosts pairs are allowed, and for each host |
| 27 | pair, an artificial point-to-point interface is constructed. |
| 28 | At some future date, IP broadcast addresses or hosts may be paired |
| 29 | with NS networks or hosts. |
| 30 | .LP |
| 31 | Specifically, a socket option of SO_NSIP_ROUTE is set on a socket |
| 32 | of family AF_NS, type SOCK_DGRAM, passing the following structure: |
| 33 | .nf |
| 34 | |
| 35 | struct nsip_req { |
| 36 | struct sockaddr rq_ns; /* must be ns format destination */ |
| 37 | struct sockaddr rq_ip; /* must be ip format gateway */ |
| 38 | short rq_flags; |
| 39 | }; |
| 40 | |
| 41 | .SH DIAGNOSTICS |
| 42 | \fBnsip%d: can't handle af%d\fP. The interface was handed |
| 43 | a message with addresses formatted in an unsuitable address |
| 44 | family; the packet was dropped. |
| 45 | .SH SEE ALSO |
| 46 | intro(4N), ns(4F) |
| 47 | .SH BUGS |
| 48 | It is absurd to have a separate pseudo-device for each pt-to-pt |
| 49 | link. |
| 50 | There is no way to change the IP address for an NS host once the |
| 51 | the encapsulation interface is set up. |
| 52 | The request should honor flags of RTF_GATEWAY to indicate |
| 53 | remote networks, and the absence of RTF_UP should be a clue |
| 54 | to remove that partner. |
| 55 | This was intended to postpone the necessity of rewriting reverse ARP |
| 56 | for the |
| 57 | .B en |
| 58 | device, and to allow passing XNS packets through an |
| 59 | Arpanet-Milnet gateway, to facilitate testing between some co-operating |
| 60 | universities. |