IPAddress construction and comparison are buggy on Arduino 3

[mathieucarbou]

Board

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Device Description

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Hardware Configuration

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Version

v3.0.0

IDE Name

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PSRAM enabled

no

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Description

The origin of this bug request comes for a bug report in my ESPAsyncWebServer maintained fork here: mathieucarbou/ESPAsyncWebServer#26

The root of the problem lies in the fact that when connected to a WiFi, both should be true.

WiFi.localIP().toString() == request->client()->localIP().toString()
WiFi.localIP() == request->client()->localIP()

But the second one is false.

This is because the library uses behind the new IPAddress construction with an ip_addr_t (following some updates from the ESPHome team). This is not wrong, but the new implementation has flaws.

The issue lies at several places:

1. the comparison operator

bool IPAddress::operator==(const IPAddress &addr) const {
  return (addr._type == _type) && (memcmp(addr._address.bytes, _address.bytes, sizeof(_address.bytes)) == 0);
}

For IPv4, it should only compare _address.dword[IPADDRESS_V4_DWORD_INDEX], not the full set of bytes

2. the constructor:

IPAddress &IPAddress::from_ip_addr_t(const ip_addr_t *addr) {
  if (addr->type == IPADDR_TYPE_V6) {
    _type = IPv6;
    _address.dword[0] = addr->u_addr.ip6.addr[0];
    _address.dword[1] = addr->u_addr.ip6.addr[1];
    _address.dword[2] = addr->u_addr.ip6.addr[2];
    _address.dword[3] = addr->u_addr.ip6.addr[3];
#if LWIP_IPV6_SCOPES
    _zone = addr->u_addr.ip6.zone;
#endif /* LWIP_IPV6_SCOPES */
  } else {
    _type = IPv4;
    _address.dword[IPADDRESS_V4_DWORD_INDEX] = addr->u_addr.ip4.addr;
  }
  return *this;
}

Which is not "clearing" the indexes 0, 1 and 2 to 0, to ensure the comparison operator works for IPv4

Any of this fix would work. I tested this one:

IPAddress &IPAddress::from_ip_addr_t(const ip_addr_t *addr) {
  if (addr->type == IPADDR_TYPE_V6) {
    _type = IPv6;
    _address.dword[0] = addr->u_addr.ip6.addr[0];
    _address.dword[1] = addr->u_addr.ip6.addr[1];
    _address.dword[2] = addr->u_addr.ip6.addr[2];
    _address.dword[3] = addr->u_addr.ip6.addr[3];
#if LWIP_IPV6_SCOPES
    _zone = addr->u_addr.ip6.zone;
#endif /* LWIP_IPV6_SCOPES */
  } else {
    _type = IPv4;
    _address.dword[0] = 0;
    _address.dword[1] = 0;
    _address.dword[2] = 0;
    _address.dword[IPADDRESS_V4_DWORD_INDEX] = addr->u_addr.ip4.addr;
  }
  return *this;
}

But I think both should be applied (also making sure that the compare operator is comparing the relevant information depending on the IP type)

Sketch

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Debug Message

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Other Steps to Reproduce

No response

I have checked existing issues, online documentation and the Troubleshooting Guide

• I confirm I have checked existing issues, online documentation and Troubleshooting guide.

[mathieucarbou]

Note: the workaround could be to not use the constructor and proceed like that:

IPAddress ip;
ip.from_ip_addr_t(ipaddr);
connect(ip, _connect_port);