Replace usage addrinfo with Ip::Address in icmp4

[jtstrs]

Replace usage of addrinfo in icmp4 with more
appropriate way

[squid-prbot]

Can one of the admins verify this patch?

[jtstrs]

As we discussed, aim of this PR is try to remove usage of addrinfo.
Since Ip::Address, have only one field sockaddr_in6 and
dont have any virtual methods, inheritance stuff and another
things, which could force compiler to add any overhead, we
could assume, that Ip::Address is byte compatible with
addrinfo and could be used directly instead of it.
At least, I think thats true for this context with Icmp4

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This pr related to #1671

[jtstrs]

Feel free to add some comments and suggestions, since, honestly, I've lack of knowledge and experience with such type things.

[rousskov]

The horrible casting aside, this change violates recvfrom() call intent (and possibly API) by supplying a nil pointer to address size (disguised as integer 0): "the caller should initialize [addrlen memory] before the call to the size of the buffer associated with src_addr"

To move this PR forward, I suggest:

• Test changes before posting a PR (or PR updates).
• Remove reinterpret_cast. If you need a sockaddr object, use a local sockaddr variable .
• Read recvfrom() documentation and understand why that specific system call is used here.
• Supply a non-nil addrlen pointer to recvfrom(). Use another local variable of the right type for this addrlen. The value of that variable will depend on how your solution provides the memory for the address, but it will not be zero.
• Add a check for recvfrom() truncating the address, report an error if it did, and do not use the truncated address.
• Do not use std::move() unless the code does not compile without it (its use is always a red flag in Squid code, but there are legitimate use cases, of course): It is difficult to use std::move() correctly, it is usually a bad idea to use it, and it is probably not going to be needed in this PR.

[yadij]

could assume, that Ip::Address is byte compatible with
addrinfo and could be used directly instead of it.

This assumption is false. IPv4 and IPv6 different in byte sizes. While the field layout of sockaddr group of structures matches, the address fields differ in size and format.

[yadij]

from should be of type sockaddr_storage and empty.

Suggested change

	Ip::Address from;
	sockaddr_storage from;
	memset(&from, 0, sizeof(from));

Also, these lines should be down just before first-use, where the recvfrom() is called.

[yadij]

Suggested change

	preply.from = std::move(from);
	preply.from = from;