aya: implement TryFrom<[Program Type]> for FdLink for various program types

[mehnazyunus]

Implements TryFrom for FdLink for CgroupSkb, CgroupSock, CgroupSockAddr and SockOps program types. This allows support for link pinning for these program types, aligning with the documentation for FdLink.

Fixes: #739

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[Copilot]

Pull Request Overview

This PR implements TryFrom conversions for FdLink for various program link types to support link pinning as referenced in the FdLink documentation.

• Added TryFrom implementations for SockOps, CgroupSockAddr, CgroupSock, and CgroupSkb program link types.
• Each conversion verifies that the link contains an FD, returning an error for ProgAttach variants.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 4 comments.

File	Description
aya/src/programs/sock_ops.rs	Added TryFrom implementation for SockOpsLink to FdLink.
aya/src/programs/cgroup_sock_addr.rs	Added TryFrom implementation for CgroupSockAddrLink to FdLink.
aya/src/programs/cgroup_sock.rs	Added TryFrom implementation for CgroupSockLink to FdLink.
aya/src/programs/cgroup_skb.rs	Added TryFrom implementation for CgroupSkbLink to FdLink.

[dave-tucker]

The Copilot review isn't completely wrong. Please could you add the following macro?

macro_rules! impl_try_into_fdlink {
    ($wrapper:ident, $inner:ident) => {
        impl TryFrom<$wrapper> for FdLink {
            type Error = LinkError;

            fn try_from(value: $wrapper) -> Result<Self, Self::Error> {
                if let $inner::FdLink(fd) = value.into_inner() {
                    Ok(fd)
                } else {
                    Err(LinkError::InvalidLink)
                }
            }
        }
    };
}

pub(crate) use impl_try_into_fdlink;

This can the be used as:

impl_try_into_fdlink!(CgroupSockLink, CgroupSockLinkInner);

Same can be done for XDP, Tc, etc... i.e all other programs that implement this.
We may have to rename some of the enum invariants to make this macro work, but that's not public API afaict so shouldn't be an issue. We've been inconsistent - sometimes it's LinkInner::Fd other times it's LinkInner::FdLink. I prefer the former so lets standardize on that if we can.

[mergify]

Hey @alessandrod, this pull request changes the Aya Public API and requires your review.

[tamird]

Please squash your commits so there is only one and run cargo xtask public-api --bless to update the API fixtures.

[tamird]

Reviewed 1 of 8 files at r4, 11 of 12 files at r5, 1 of 4 files at r6, 4 of 4 files at r7, all commit messages.
Reviewable status: all files reviewed, 4 unresolved discussions (waiting on @alessandrod, @dave-tucker, and @mehnazyunus)

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aya/src/programs/links.rs line 561 at r7 (raw file):

macro_rules! impl_try_into_fdlink {
    ($wrapper:ident, $inner:ident) => {
        impl TryFrom<$wrapper> for FdLink {

please use $crate::programs::FdLink to avoid having to import it in all the invokers.

---

aya/src/programs/links.rs line 562 at r7 (raw file):

    ($wrapper:ident, $inner:ident) => {
        impl TryFrom<$wrapper> for FdLink {
            type Error = LinkError;

please use $crate::programs::LinkError to avoid having to import it in all the invokers.

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aya/src/programs/links.rs line 568 at r7 (raw file):

                    Ok(fd)
                } else {
                    Err(LinkError::InvalidLink)

ditto.

[mergify]

Hey @alessandrod, this pull request changes the Aya Public API and requires your review.

[tamird]

Code looks good but needs a rebase and another squash.

Reviewed 2 of 16 files at r8, 14 of 14 files at r9, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @alessandrod, @dave-tucker, and @mehnazyunus)

[tamird]

Reviewed 3 of 3 files at r10, all commit messages.
Reviewable status: all files reviewed, 1 unresolved discussion (waiting on @alessandrod, @dave-tucker, and @mehnazyunus)

[Copilot]

Pull Request Overview

This PR introduces TryFrom implementations for FdLink for several program types (CgroupSkb, CgroupSock, CgroupSockAddr, SockOps, etc.) to support link pinning as documented. It leverages a new macro (impl_try_into_fdlink) to reduce boilerplate and updates enum variant names (from FdLink to Fd) for consistency across modules.

• Uses a new macro to consolidate TryFrom implementations.
• Updates naming from FdLink to Fd in internal enums.
• Revises the public API documentation to expose these changes.

Reviewed Changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
xtask/public-api/aya.txt	Updated API doc to include the new TryFrom implementations (check for duplicate entries).
aya/src/programs/xdp.rs	Renamed internal enum variant from FdLink to Fd and updated conversion logic.
aya/src/programs/uprobe.rs	Replaced explicit TryFrom implementation with macro usage.
aya/src/programs/trace_point.rs	Similar macro conversion and variant name update.
aya/src/programs/tc.rs	Converted TryFrom implementations and renamed enum variants.
aya/src/programs/sock_ops.rs	Added macro conversion for SockOpsLink.
aya/src/programs/perf_event.rs	Applied macro usage and updated conversion fallbacks.
aya/src/programs/perf_attach.rs	Updated enum variant naming in PerfLinkInner.
aya/src/programs/kprobe.rs	Replaced explicit TryFrom with macro usage.
aya/src/programs/iter.rs	Consolidated TryFrom implementations using the macro.
aya/src/programs/cgroup_sock_addr.rs	Added macro implementation for TryFrom.
aya/src/programs/cgroup_sock.rs	Added macro implementation for TryFrom.
aya/src/programs/cgroup_skb.rs	Added macro implementation for TryFrom.

Comments suppressed due to low confidence (1)

aya/src/programs/xdp.rs:161

• [nitpick] The renaming of the enum variant from 'FdLink' to 'Fd' improves consistency; please ensure that all related documentation and references are updated accordingly.

.insert(XdpLink::new(XdpLinkInner::Fd(FdLink::new(link_fd))))