9.12. 網路位址函式及運算子
Table 9.36shows the operators available for thecidr
andinet
types. The operators<<
,<<=
,>>
,>>=
, and&&
test for subnet inclusion. They consider only the network parts of the two addresses (ignoring any host part) and determine whether one network is identical to or a subnet of the other.
Table 9.36. cidr
andinet
Operators
Operator | Description | Example | ||
---|---|---|---|---|
< |
is less than | inet '192.168.1.5' < inet '192.168.1.6' |
||
<= |
is less than or equal | inet '192.168.1.5' <= inet '192.168.1.5' |
||
= |
equals | inet '192.168.1.5' = inet '192.168.1.5' |
||
>= |
is greater or equal | inet '192.168.1.5' >= inet '192.168.1.5' |
||
> |
is greater than | inet '192.168.1.5' > inet '192.168.1.4' |
||
<> |
is not equal | inet '192.168.1.5' <> inet '192.168.1.4' |
||
<< |
is contained by | inet '192.168.1.5' << inet '192.168.1/24' |
||
<<= |
is contained by or equals | inet '192.168.1/24' <<= inet '192.168.1/24' |
||
>> |
contains | inet '192.168.1/24' >> inet '192.168.1.5' |
||
>>= |
contains or equals | inet '192.168.1/24' >>= inet '192.168.1/24' |
||
&& |
contains or is contained by | inet '192.168.1/24' && inet '192.168.1.80/28' |
||
~ |
bitwise NOT | ~ inet '192.168.1.6' |
||
& |
bitwise AND | inet '192.168.1.6' & inet '0.0.0.255' |
||
` | ` | bitwise OR | `inet ‘192.168.1.6’ | inet ‘0.0.0.255’` |
+ |
addition | inet '192.168.1.6' + 25 |
||
- |
subtraction | inet '192.168.1.43' - 36 |
||
- |
subtraction | inet '192.168.1.43' - inet '192.168.1.19' |
Table 9.37shows the functions available for use with thecidr
andinet
types. Theabbrev
,host
, andtext
functions are primarily intended to offer alternative display formats.
Table 9.37. cidr
andinet
Functions
Function | Return Type | Description | Example | Result |
---|---|---|---|---|
abbrev(inet ) |
text |
abbreviated display format as text | abbrev(inet '10.1.0.0/16') |
10.1.0.0/16 |
abbrev(cidr ) |
text |
abbreviated display format as text | abbrev(cidr '10.1.0.0/16') |
10.1/16 |
broadcast(inet ) |
inet |
broadcast address for network | broadcast('192.168.1.5/24') |
192.168.1.255/24 |
family(inet ) |
int |
extract family of address;4 for IPv4,6 for IPv6 |
family('::1') |
6 |
host(inet ) |
text |
extract IP address as text | host('192.168.1.5/24') |
192.168.1.5 |
hostmask(inet ) |
inet |
construct host mask for network | hostmask('192.168.23.20/30') |
0.0.0.3 |
masklen(inet ) |
int |
extract netmask length | masklen('192.168.1.5/24') |
24 |
netmask(inet ) |
inet |
construct netmask for network | netmask('192.168.1.5/24') |
255.255.255.0 |
network(inet ) |
cidr |
extract network part of address | network('192.168.1.5/24') |
192.168.1.0/24 |
set_masklen(inet ,int ) |
inet |
set netmask length forinet value |
set_masklen('192.168.1.5/24', 16) |
192.168.1.5/16 |
set_masklen(cidr ,int ) |
cidr |
set netmask length forcidr value |
set_masklen('192.168.1.0/24'::cidr, 16) |
192.168.0.0/16 |
text(inet ) |
text |
extract IP address and netmask length as text | text(inet '192.168.1.5') |
192.168.1.5/32 |
inet_same_family(inet ,inet ) |
boolean |
are the addresses from the same family? | inet_same_family('192.168.1.5/24', '::1') |
false |
inet_merge(inet ,inet ) |
cidr |
the smallest network which includes both of the given networks | inet_merge('192.168.1.5/24', '192.168.2.5/24') |
192.168.0.0/22 |
Anycidr
value can be cast toinet
implicitly or explicitly; therefore, the functions shown above as operating oninet
also work oncidr
values. (Where there are separate functions forinet
andcidr
, it is because the behavior should be different for the two cases.) Also, it is permitted to cast aninet
value tocidr
. When this is done, any bits to the right of the netmask are silently zeroed to create a validcidr
value. In addition, you can cast a text value toinet
orcidr
using normal casting syntax: for example,inet(expression
)orcolname
::cidr.
Table 9.38shows the functions available for use with themacaddr
type. The functiontrunc(macaddr
)returns a MAC address with the last 3 bytes set to zero. This can be used to associate the remaining prefix with a manufacturer.
Table 9.38. macaddr
Functions
Function | Return Type | Description | Example | Result |
---|---|---|---|---|
trunc(macaddr ) |
macaddr |
set last 3 bytes to zero | trunc(macaddr '12:34:56:78:90:ab') |
12:34:56:00:00:00 |
Themacaddr
type also supports the standard relational operators (>
,<=
, etc.) for lexicographical ordering, and the bitwise arithmetic operators (~
,&
and|
) for NOT, AND and OR.
Table 9.39shows the functions available for use with themacaddr8
type. The functiontrunc(macaddr8
)returns a MAC address with the last 5 bytes set to zero. This can be used to associate the remaining prefix with a manufacturer.
Table 9.39. macaddr8
Functions
Function | Return Type | Description | Example | Result |
---|---|---|---|---|
trunc(macaddr8 ) |
macaddr8 |
set last 5 bytes to zero | trunc(macaddr8 '12:34:56:78:90:ab:cd:ef') |
12:34:56:00:00:00:00:00 |
macaddr8_set7bit(macaddr8 ) |
macaddr8 |
set 7th bit to one, also known as modified EUI-64, for inclusion in an IPv6 address | macaddr8_set7bit(macaddr8 '00:34:56:ab:cd:ef') |
02:34:56:ff:fe:ab:cd:ef |
Themacaddr8
type also supports the standard relational operators (>
,<=
, etc.) for ordering, and the bitwise arithmetic operators (~
,&
and|
) for NOT, AND and OR.