No IP classification functions (`is_ip_loopback`, `is_ip_unspecified`, `is_public_addr`, `is_private_addr`)

[sumanjeet0012]

Go's manet package provides comprehensive IP classification functions that operate on Multiaddr objects. Python has is_wildcard() and is_link_local_ip() in utils.py, but they take raw strings instead of Multiaddr objects and miss several important classifications.

Problem

Go provides:

Function	Description
IsThinWaist(ma)	Is it /{ip4,ip6}[/{tcp,udp}]?
IsIPLoopback(ma)	Is it 127.0.0.0/8 or ::1?
IsIPUnspecified(ma)	Is it 0.0.0.0 or ::?
IsIP6LinkLocal(ma)	Is it fe80::/10?
IsPublicAddr(ma)	Is it publicly routable?
IsPrivateAddr(ma)	Is it in a private network?
IsNAT64IPv4ConvertedIPv6Addr(ma)	Is it NAT64?

Python provides:

Function	Takes	Description
is_wildcard(ip: str)	Raw string	Only checks "0.0.0.0" or "::"
is_link_local_ip(ip: str)	Raw string	Checks fe80: or 169.254
get_multiaddr_options(ma)	Multiaddr	Implicit thin waist check

Missing: is_ip_loopback, is_ip_unspecified (on Multiaddr), is_public_addr, is_private_addr, is_thin_waist, is_nat64.

Proposed Solution

Add to utils.py:

import ipaddress

# Well-known multiaddr constants
IP4_LOOPBACK = Multiaddr("/ip4/127.0.0.1")
IP6_LOOPBACK = Multiaddr("/ip6/::1")
IP4_UNSPECIFIED = Multiaddr("/ip4/0.0.0.0")
IP6_UNSPECIFIED = Multiaddr("/ip6/::")

# Private CIDR ranges
PRIVATE4 = [ipaddress.ip_network(cidr) for cidr in [
    "127.0.0.0/8", "10.0.0.0/8", "100.64.0.0/10",
    "172.16.0.0/12", "192.168.0.0/16", "169.254.0.0/16",
]]
PRIVATE6 = [ipaddress.ip_network(cidr) for cidr in [
    "::1/128", "fc00::/7", "fe80::/10",
]]

def is_thin_waist(ma: Multiaddr) -> bool: ...
def is_ip_loopback(ma: Multiaddr) -> bool: ...
def is_ip_unspecified(ma: Multiaddr) -> bool: ...
def is_ip6_link_local(ma: Multiaddr) -> bool: ...
def is_public_addr(ma: Multiaddr) -> bool: ...
def is_private_addr(ma: Multiaddr) -> bool: ...

Each function extracts the IP from the multiaddr and checks against the appropriate ranges.

Related

• Go implementation: go-multiaddr net/ip.go, net/private.go