Hi,

On Tue, May 02, 2023 at 04:34:15PM +0400, Roman Arutyunyan wrote:
> # HG changeset patch
> # User Roman Arutyunyan <arut@nginx.com>
> # Date 1682679819 -14400
> # Fri Apr 28 15:03:39 2023 +0400
> # Branch quic
> # Node ID 43f0ceffa227a33e5c5ceb35b77f9a1f86dd2481
> # Parent cdc41ec778ffae822fefce639e67f2f57e3667f0
> QUIC: keep stream sockaddr and addr_text constant.
>
> HTTP and Stream variables $remote_addr and $binary_remote_addr rely on
> constant client address, particularly because they are cacheable.
> However, QUIC client may migrate to a new address. While there's no perfect
> way to handle this, the proposed solution is to copy client address to QUIC
> stream at stream creation. Previously, the address was only referenced, which
> could result in changing it while stream was active, which in turn would lead
> to broken cached variables values, since address length is cached as well.

While testing this, it was found that $remote_addr truncation happens at the
QUIC level since the addr_text string is copied by value and retains the old
length after migration. The new commit log:

QUIC: keep stream sockaddr and addr_text constant.

HTTP and Stream variables $remote_addr and $binary_remote_addr rely on
constant client address, particularly because they are cacheable.
However, QUIC client may migrate to a new address. While there's no perfect
way to handle this, the proposed solution is to copy client address to QUIC
stream at stream creation.

The change also fixes truncated $remote_addr if migration happened while the
stream was active. The reason is addr_text string was copied to stream by
value.

[..]

--
Roman Arutyunyan
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