IP(2) System Calls Manual IP(2)

IP - Internet Protocol addresses and interfaces

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;


   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);

IP provides data types and operations that manipulate Internet 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:

Return an IPaddr representing the IPv6 address stored in a as an array of 16 bytes
Return an IPaddr representing the IPv4 address stored in a as an array of 4 bytes
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.
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.
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 giving 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 values for the address and mask given by s. If ok is negative, s is invalid.
Return a copy of the value ip
Return true (non-zero) if ip represents the same address as v; return false (zero) otherwise.
Return the value (ip&m), that is, address ip masked by m
Return true if ip is an IPv4 address; return false if otherwise (it can only be used on a full IPv6 network)
Return the value of ip as a 4-byte array in IPv4 representation if it can be so represented; if ip is not an IPv4 address, return nil.
Return the value of ip in IPv6 addressing format as an array of 16 bytes
If ip is an IPv4 address, return its class (0 to 3); if it is an IPv6 address, return 6.
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.
Return true if ip is a multicast or broadcast address.
Return true if ip is not the zero address in either IPv4 or IPv6 address space
Return a textual representation of the address ip in either IPv4 or IPv6 format as appropriate.
Return a textual representation of the address ip as one of: an IPv4 mask; /n where n is the number of leading 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 contains a list of local interface addresses, addrs. Each local address is represented by an Iplifc value in that list.

/net/ipifc
directory of IP interfaces
/net/ipifc/n/status
status and addresses of interface n

/appl/lib/ip.b

ether (2), ip (3)

Readipifc is currently only usable in native Inferno. That will change shortly.