implement-handling-of-ipv6-addresses-reserved-ranges

[lnarolski]

Problem statement
Currently eBPF Discovery only partially handles IPv6 addressing, that is mapped IPv4 into IPv6. Other IPv6 http requests are neglected and not counted as internal/external clients for discovered services.

Solution proposal
IpAddressNetlinkChecker::isV6AddressExternal() implement checks (check if address prefix matches the one provided) for:

• unique local address (prefix fc00::/7)
• site local addresses (fec0::/10 - deprecated)
• link local addresses (fe80::/10)
• loopback addresses (::1/128)
• address is from the same subnet as any local ipv6 interfaces

getMappedIPv4Addr() add checks for IPv4/IPv6 translated address
check for prefixes: (::ffff:0:0:0/96) and (64:ff9b::/96) and handle as mapped IPv4/IPv6

Success criteria
IPv6 addresses are recognized as local if any of the following rules apply:

• is unique local address
• is site local address
• is link local addresses
• is loopback address
• IPv4/IPv6 translated address are handled in the same manner as IPv4/IPv6 mapped addresses

Unit tests added for all implemented rules

[dynatrace-cla-bot]

All committers have signed the CLA.