9.12. 網路位址函式及運算子
Table 9.36shows the operators available for the
cidr
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
OperatorsOperator | Description | Example | Text | Text |
---|---|---|---|---|
< | 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 the
cidr
andinet
types. Theabbrev
,host
, andtext
functions are primarily intended to offer alternative display formats.**Table 9.37. **
cidr
andinet
FunctionsFunction | 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 for inet value | set_masklen('192.168.1.5/24', 16) | 192.168.1.5/16 |
set_masklen(cidr ,int ) | cidr | set netmask length for cidr 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 |
Any
cidr
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 the
macaddr
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
FunctionsFunction | 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 |
The
macaddr
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 the
macaddr8
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
FunctionsFunction | 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 |
The
macaddr8
type also supports the standard relational operators (>
,<=
, etc.) for ordering, and the bitwise arithmetic operators (~
,&
and|
) for NOT, AND and OR.