IP(2) IP(2)
NAME
IP - Internet Protocol addresses and interfaces
SYNOPSIS
include "ip.m";
ip := load IP IP->PATH;
IPaddr: import IP;
IPaddr: adt {
newv6: fn(nil: array of byte): IPaddr;
newv4: fn(nil: array of byte): IPaddr;
copy: fn(nil: self IPaddr): IPaddr;
eq: fn(nil: self IPaddr, v: IPaddr): int;
mask: fn(nil: self IPaddr, m: IPaddr): IPaddr;
isv4: fn(nil: self IPaddr): int;
ismulticast: fn(nil: self IPaddr): int;
isvalid: fn(nil: self IPaddr): int;
v4: fn(nil: self IPaddr): array of byte;
v6: fn(nil: self IPaddr): array of byte;
class: fn(nil: self IPaddr): int;
classmask: fn(nil: self IPaddr): IPaddr;
parse: fn(s: string): (int, IPaddr);
parsemask: fn(s: string): (int, IPaddr);
parsecidr: fn(s: string): (int, IPaddr, IPaddr);
text: fn(nil: self IPaddr): string;
masktext: fn(nil: self IPaddr): string;
};
v4bcast, v4allsys, v4allrouter, noaddr, allbits: IPaddr;
selfv6, selfv4: IPaddr;
v4prefix: array of byte;
Ifcaddr: adt {
ip: IPaddr; # local interface address
mask: IPaddr; # subnet mask
net: IPaddr; # ip & mask
preflt: big; # preferred life time
validlt: big; # valid life time
};
Ipifc: adt {
index: int; # /net/ipifc/N
dev: string; # bound device
addrs: list of ref Ifcaddr;
sendra: int; # !=0, send router adverts
recvra: int; # !=0, receive router adverts
mtu: int;
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pktin: big; # packets in
pktout: big; # packets out
errin: big; # input errors
errout: big; # output errors
rp: IPv6rp; # IPv6 route advert parameters
};
IPv6rp: adt {
mflag: int;
oflag: int;
maxraint: int; # max route advert interval
minraint: int; # min route advert interval
linkmtu: int;
reachtime: int;
rxmitra: int;
ttl: int;
routerlt: int;
};
init: fn();
readipifc: fn(net: string, index: int): (list of ref Ipifc, string);
DESCRIPTION
IP provides data types and operations that manipulate Inter-
net Protocol addresses, and operations that convert between
internal and textual address forms, for both IPv4 and IPv6.
The textual forms are those defined by RFC2373. Briefly, an
IPv6 address is 16 bytes, represented textually as a
sequence of 8 colon-separated hexadecimal values ranging
from 0 to FFFF, except that any one sequence of zeroes can
be replaced by ::. IPv4 addresses are embedded in the IPv6
space with a prefix of either 0:0:0:0:0:FFFF (for addresses
of `IPv4-mapped' nodes), or 0:0:0:0:0:0 (for `IPv4-
compatible' IPv6 nodes). See RFC2373 for the distinction.
For convenience in working with such addresses, the textual
syntax allows the last 4 bytes of an IPv6 address to be
specified using a restricted IPv4 syntax, allowing an
address to end in four dot-separated decimal values (for
example, 0:0:0:0:0:FFFF:127.0.0.1 for the IPv4 loopback
address). The functions here also accept the common forms
of IPv4 syntax with one or two values omitted (eg, 127.1 for
the loopback address), and accept IPv4 format for masks (eg,
255.255.254.0).
Init must be called once before using any value or function
of the module.
An Internet address or network mask is represented by an
IPaddr value. It has the following operations:
IPaddr.newv6(a)
Return an IPaddr representing the IPv6 address stored
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IP(2) IP(2)
in a as an array of 16 bytes
IPaddr.newv4(a)
Return an IPaddr representing the IPv4 address stored
in a as an array of 4 bytes
IPaddr.parse(s)
Return a tuple (ok,ip). If ok is 0, ip is an IPaddr
representing the address in textual format in the
string s, which can be in either IPv4 or IPv6 syntax.
If ok is negative, s was invalid.
IPaddr.parsemask(s)
S is a text string defining a mask, in one of three
forms: /nbits where nbits is the number of leading one
bits in the mask, ranging from 0 to 128; an IPv4 mask
(eg, 255.255.254.0); or an IPv6 mask. Return a tuple
(ok,m). If ok is 0, m is an IPaddr representing the
mask given by s. If ok is negative, s was invalid.
IPaddr.parsecidr(s)
S is an address-mask combination in Classless Inter-
Domain Routing (CIDR) format: ip-address/prefix-length,
where ip-address is an address in any form accepted by
parse above, and prefix-length is a decimal value giv-
ing the number of leftmost bits in ip-address that form
the addressing prefix (ie, subnet prefix). Return a
tuple (ok,ip,m). If ok is 0, ip and m are IPaddr val-
ues for the address and mask given by s. If ok is nega-
tive, s is invalid.
ip.copy()
Return a copy of the value ip
ip.eq(v)
Return true (non-zero) if ip represents the same
address as v; return false (zero) otherwise.
ip.mask(m)
Return the value (ip&m), that is, address ip masked by
m
ip.isv4()
Return true if ip is an IPv4 address; return false if
otherwise (it can only be used on a full IPv6 network)
ip.v4()
Return the value of ip as a 4-byte array in IPv4 repre-
sentation if it can be so represented; if ip is not an
IPv4 address, return nil.
ip.v6()
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IP(2) IP(2)
Return the value of ip in IPv6 addressing format as an
array of 16 bytes
ip.class()
If ip is an IPv4 address, return its class (0 to 3); if
it is an IPv6 address, return 6.
ip.classmask()
If ip is an IPv4 address, return the mask associated
with its class; if ip is an IPv6 address, return a mask
that is all ones.
ip.ismulticast()
Return true if ip is a multicast or broadcast address.
ip.isvalid()
Return true if ip is not the zero address in either
IPv4 or IPv6 address space
ip.text()
Return a textual representation of the address ip in
either IPv4 or IPv6 format as appropriate.
ip.masktext()
Return a textual representation of the address ip as
one of: an IPv4 mask; /n where n is the number of lead-
ing 1 bits, as used in CIDR syntax; or as a full IPv6
textual address. The format used is appropriate to the
structure of the value.
The module provides some predefined IPaddr values, mainly
for common IPv4 addresses: v4bcast (broadcast address),
v4allsys (all hosts multicast address), v4allrouter (all
routers multicast address), selfv4 (loopback in IPv4),
selfv6 (loopback in IPv6), noaddr (all zero address, used
before a node has an address), v4noaddr (all zero address
with IPv4 prefix), and allbits (address of all 1 bits). The
12-byte IPv6 prefix for IPv4 embedded addresses is provided
in the array of bytes v4prefix.
Readipifc returns a list of the host's IP interfaces and the
attributes and addresses of each, read from the interface
status files in /net/ipifc. On an error, the string in the
returned tuple contains a diagnostic and the list is nil.
Each interface is represented by an Ipifc value, which con-
tains a list of local interface addresses, addrs. Each
local address is represented by an Iplifc value in that
list.
FILES
/net/ipifc directory of IP interfaces
/net/ipifc/n/status status and addresses of interface n
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SOURCE
/appl/lib/ip.b
SEE ALSO
ether(2), ip(3)
BUGS
Readipifc is currently only usable in native Inferno. That
will change shortly.
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