#include "source/common/network/ip_address_parsing.h"

#include <cstring>

#include "source/common/api/os_sys_calls_impl.h"

namespace Envoy {

namespace Network {

namespace IpAddressParsing {

  // Use inet_pton() for IPv4 as it's simpler, faster, and already enforces

  // strict dotted-quad format while rejecting non-standard notations.

  // Parse IPv6 with optional scope using getaddrinfo().

  // While inet_pton() would be faster and simpler, it does not support IPv6

  // addresses that specify a scope, e.g. `::%eth0` to listen on only one interface.

  // Suppresses any potentially lengthy network host address lookups and inhibit the

  // invocation of a name resolution service.

  // Given that we do not specify a service but we use getaddrinfo() to only parse the node

  // address, specifying the socket type allows to hint the getaddrinfo() to return only an

  // element with the below socket type. The behavior though remains platform dependent and

  // anyway we consume only the first element if the call succeeds.

  // We want to use the interface of OsSysCalls for this for the platform-independence, but

  // we do not want to use the common OsSysCallsSingleton.

  //

  // The problem with using OsSysCallsSingleton is that we likely want to override getaddrinfo()

  // for DNS lookups in tests, but typically that override would resolve a name to e.g. the

  // address from resolveUrl("tcp://[::1]:80"). But resolveUrl calls ``parseIPv6``, which calls

  // getaddrinfo(), so if we use the mock here then mocking DNS causes infinite recursion.

  //

  // We do not ever need to mock this getaddrinfo() call, because it is only used to parse

  // numeric IP addresses, per ``ai_flags``, so it should be deterministic resolution. There

  // is no need to mock it to test failure cases.

} // namespace IpAddressParsing

} // namespace Network

} // namespace Envoy