Add methods to TCP and UDP sockets to modify hop limit (refresh of #94678)

[Mallets]

#94678 was closed because of time constraints of the original author (@kckeiks).

This PR is a refresh of #94678 where the original proposed changes are ported to the current status of the standard library.

In addition, this PR:

• implements the change suggested in add methods to TCP and UDP sockets to modify hop limit #94678 (comment)
• defines set_multicast_hop_limit_v6 and multicast_hop_limit_v6 only for UDP sockets and not for TCP sockets as originally proposed

Issue: #139166

[rustbot]

r? @ibraheemdev

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[ibraheemdev]

r? libs-api because it's been a while since the original PR was approved.

[bors]

☔ The latest upstream changes (presumably #139724) made this pull request unmergeable. Please resolve the merge conflicts.

[dtolnay]

Sorry—I missed that this was ready for review again. Please use @rustbot ready, which replaces S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label with S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. .

[dtolnay]

@rustbot ready

[dtolnay]

Thank you!

@bors r+

[bors]

📌 Commit 25fb525 has been approved by dtolnay

It is now in the queue for this repository.

[jhpratt]

@bors r-

#141561 (comment)

[Mallets]

Would it be possible to re-kick the CI to get the failure logs?

[Dylan-DPC]

Not sure if this reproduces the error but we can try

@bors try

[rust-bors]

☀️ Try build successful (CI)
Build commit: 6b5fa05 (6b5fa054a42b37f7e0057cdcaf96ceff75677206, parent: 033c0a4742794f5608b19eb78458726596f8ec18)

[Mallets]

@Dylan-DPC the build succeed

[bors]

☔ The latest upstream changes (presumably #146418) made this pull request unmergeable. Please resolve the merge conflicts.

[dtolnay]

You can reproduce the failure with x.py check library/std --target=wasm32-wasip2. "bors try" does not cover the full cross-compilation matrix.

Checking stage1 library artifacts{std} (stage1:x86_64-unknown-linux-gnu -> stage1:wasm32-wasip2)
    Checking std v0.0.0
warning: dropping unsupported crate type `dylib` for target `wasm32-wasip2`

error[E0425]: cannot find value `IPV6_MULTICAST_HOPS` in crate `c`
   --> library/std/src/sys/net/connection/socket/mod.rs:831:53
    |
831 |         setsockopt(&self.inner, c::IPPROTO_IPV6, c::IPV6_MULTICAST_HOPS, limit as c_int)
    |                                                     ^^^^^^^^^^^^^^^^^^^ help: a constant with a similar name exists: `IPV6_MULTICAST_LOOP`
    |
   ::: /home/david/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/libc-0.2.175/src/wasi/p2.rs:117:1
    |
117 | pub const IPV6_MULTICAST_LOOP: c_int = 19;
    | ------------------------------------ similarly named constant `IPV6_MULTICAST_LOOP` defined here

error[E0425]: cannot find value `IPV6_MULTICAST_HOPS` in crate `c`
   --> library/std/src/sys/net/connection/socket/mod.rs:835:70
    |
835 |         let raw: c_int = getsockopt(&self.inner, c::IPPROTO_IPV6, c::IPV6_MULTICAST_HOPS)?;
    |                                                                      ^^^^^^^^^^^^^^^^^^^ help: a constant with a similar name exists: `IPV6_MULTICAST_LOOP`
    |
   ::: /home/david/.cargo/registry/src/index.crates.io-1949cf8c6b5b557f/libc-0.2.175/src/wasi/p2.rs:117:1
    |
117 | pub const IPV6_MULTICAST_LOOP: c_int = 19;
    | ------------------------------------ similarly named constant `IPV6_MULTICAST_LOOP` defined here

[rustbot]

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.