IP(2) IP(2)
NAME
eipfmt, parseip, parseipmask, parseipandmask, v4parseip,
parseether, myipaddr, myetheraddr, maskip, equivip4,
equivip6, defmask, isv4, v4tov6, v6tov4, nhgetv, nhgetl,
nhgets, hnputv, hnputl, hnputs, ptclbsum, readipifc -
Internet Protocol addressing
SYNOPSIS
#include <u.h>
#include <libc.h>
#include <ip.h>
int eipfmt(Fmt*)
vlong parseip(uchar *ipaddr, char *str)
vlong parseipmask(uchar *ipaddr, char *str, int v4)
vlong parseipandmask(uchar *ipaddr, uchar *ipmask, char
*ipstr, char *maskstr)
char* v4parseip(uchar *ipaddr, char *str)
int parseether(uchar *eaddr, char *str)
int myetheraddr(uchar *eaddr, char *dev)
int myipaddr(uchar *ipaddr, char *net)
void maskip(uchar *from, uchar *mask, uchar *to)
int equivip4(uchar *ipaddr1, uchar *ipaddr2)
int equivip6(uchar *ipaddr1, uchar *ipaddr2)
uchar* defmask(uchar *ipaddr)
int isv4(uchar *ipaddr)
void v4tov6(uchar *ipv6, uchar *ipv4)
int v6tov4(uchar *ipv4, uchar *ipv6)
ushort nhgets(void *p)
uint nhgetl(void *p)
uvlong nhgetv(void *p)
void hnputs(void *p, ushort v)
Page 1 Plan 9 (printed 11/18/24)
IP(2) IP(2)
void hnputl(void *p, uint v)
void hnputv(void *p, uvlong v)
ushort ptclbsum(uchar *a, int n)
Ipifc* readipifc(char *net, Ipifc *ifc, int index)
uchar IPv4bcast[IPaddrlen];
uchar IPv4allsys[IPaddrlen];
uchar IPv4allrouter[IPaddrlen];
uchar IPallbits[IPaddrlen];
uchar IPnoaddr[IPaddrlen];
uchar v4prefix[IPaddrlen];
DESCRIPTION
These routines are used by Internet Protocol (IP) programs
to manipulate IP and Ethernet addresses. Plan 9, by
default, uses V6-format IP addresses. Since V4 addresses
fit into the V6 space, all IP addresses can be represented.
IP addresses are stored as a string of 16 unsigned chars,
Ethernet addresses as 6 unsigned chars. Either V4 or V6
string representation can be used for IP addresses. For V4
addresses, the representation can be (up to) 4 decimal inte-
gers from 0 to 255 separated by periods. For V6 addresses,
the representation is (up to) 8 hex integers from 0x0 to
0xFFFF separated by colons. Strings of 0 integers can be
elided using two colons. For example, FFFF::1111 is equiva-
lent to FFFF:0:0:0:0:0:0:1111. The string representation
for IP masks is a superset of the address representation.
It includes slash notation that indicates the number of
leading 1 bits in the mask. Thus, a V4 class C mask can be
represented as FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FFFF:FF00,
255.255.255.0, or /120. The string representation of Ether-
net addresses is exactly 12 hexadecimal digits.
Eipfmt is a print(2) formatter for Ethernet (verb E)
addresses, IP V6 (verb I) addresses, IP V4 (verb V)
addresses, and IP V6 (verb M) masks.
Parseip converts a string pointed to by str to a 16-byte IP
address starting at ipaddr. As a concession to backwards
compatibility, if the string is a V4 address, the return
value is an unsigned long integer containing the big-endian
V4 address. If not, the return value is 6.
Parseipmask converts a string pointed to by str to a 16-byte
Page 2 Plan 9 (printed 11/18/24)
IP(2) IP(2)
IP mask starting at ipaddr. It too returns an unsigned long
big-endian V4 address or 6. Parseipmask accepts a mask in
/prefixlen slash notation. When the v4 argument is non-zero,
then prefixlen in range [0..32] is offset by 96 to yield a
mask for a V4 address.
Parseipandmask combines parseip and parseipmask into a sin-
gle call, interpreting the mask in context of the supplied
IP address type. The returned IP mask is /128 when maskstr
is nil.
All three functions return -1 on errors.
V4parseip converts a string pointed to by str to a 4-byte V4
IP address starting at ipaddr.
Myipaddr returns the first valid IP address in the IP stack
rooted at net.
Parseether converts a string pointed to by str to a 6-byte
Ethernet address starting at eaddr. Myetheraddr reads the
Ethernet address string from file dev/addr and parses it
into eaddr. Both routines return a negative number on
errors.
Maskip places the bit-wise AND of the IP addresses pointed
to by its first two arguments into the buffer pointed to by
the third.
Equivip returns non-zero if the IP addresses pointed to by
its two arguments are equal. Equivip4 operates on v4
addresses, equivip6 operates on v6 addresses.
Defmask returns the standard class A, B, or C mask for
ipaddr.
Isv4 returns non-zero if the V6 address is in the V4 space,
that is, if it starts with 0:0:0:0:0:0:FFFF. V4tov6 con-
verts the 4-byte V4 address, v4ip, to a V6 address and puts
the result in v6ip. V6tov4 converts the V6 address, v6ip, to
a 4-byte V4 address and puts the result in v4ip.
Hnputs, hnputl and hnputv are used to store 16-bit, 32-bit,
and 64-bit integers, respectively, into IP big-endian form.
Nhgets, nhgetl and nhgetv convert big-endian 2, 4 and 8 byte
quantities into integers (or uvlongs).
Pctlbsum returns the one's complement checksum used in IP
protocols, typically invoked as
hnputs(hdr->cksum, ~ptclbsum(data, len) & 0xffff);
Page 3 Plan 9 (printed 11/18/24)
IP(2) IP(2)
A number of standard IP addresses in V6 format are also
defined. They are:
IPv4bcast the V4 broadcast address
IPv4allsys the V4 all systems multicast address
IPv4allrouter the V4 all routers multicast address
IPallbits the V6 all bits on address
IPnoaddr the V6 null address, all zeros
v4prefix the IP V6 prefix to all embedded V4 addresses
Readipifc returns information about a particular interface
(index >= 0) or all IP interfaces (index < 0) configured
under a mount point net, default /net. Each interface is
described by one Ipifc structure which in turn points to a
linked list of Iplifc structures describing the addresses
assigned to this interface. If the list ifc is supplied,
that list is freed. Thus, subsequent calls can be used to
free the list returned by the previous call. Ipifc is:
typedef struct Ipifc
{
Ipifc *next;
Iplifc *lifc; /* local addressses */
/* per ip interface */
int index; /* number of interface in ipifc dir */
char dev[64]; /* associated physical device */
int mtu; /* max transfer unit */
uchar sendra6; /* on == send router adv */
uchar recvra6; /* on == rcv router adv */
ulong pktin; /* packets read */
ulong pktout; /* packets written */
ulong errin; /* read errors */
ulong errout; /* write errors */
Ipv6rp rp; /* route advertisement params */
} Ipifc;
Iplifc is:
struct Iplifc
{
Iplifc *next;
uchar ip[IPaddrlen];
uchar mask[IPaddrlen];
uchar net[IPaddrlen]; /* ip & mask */
ulong preflt; /* preferred lifetime */
ulong validlt; /* valid lifetime */
};
Page 4 Plan 9 (printed 11/18/24)
IP(2) IP(2)
Ipv6rp is:
struct Ipv6rp
{
int mflag;
int oflag;
int maxraint; /* max route adv interval */
int minraint; /* min route adv interval */
int linkmtu;
int reachtime;
int rxmitra;
int ttl;
int routerlt;
};
Dev contains the first 64 bytes of the device configured
with this interface. Net is ip&mask if the network is mul-
tipoint or the remote address if the network is point to
point.
SOURCE
/sys/src/libip
SEE ALSO
print(2), ip(3)
Page 5 Plan 9 (printed 11/18/24)