[HUST CSE][components][net][sal] harden socket lifetime and close handling

[Telecaster2147]

拉取/合并请求描述：(PR description)

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为什么提交这份PR (why to submit this PR)

当前 SAL socket 路径里，socket 描述符查表、对象使用、以及 close/reuse 之间缺少统一的生命周期约束。原有实现至少存在两类问题：

• 已关闭 socket 再次进入 SAL API 时，旧代码可能先解引用空槽位或无效对象，而不是稳定返回错误；
• 并发场景下，一个线程在 lookup 后持有裸指针，另一个线程同时 close 并回收/复用该对象，会形成 stale object/use-after-close 风险。

这类问题集中出现在 components/net/sal/src/sal_socket.c 的 socket lookup、delete、close 和多条 API 入口路径中，影响 SAL 的健壮性和并发安全性，值得单独修复。

你的解决方案是什么 (what is your solution)

本 PR 对 SAL socket 生命周期做了统一收敛，并补充对应回归测试：

• 在 struct sal_socket 中增加显式生命周期状态和引用计数；
• 将 sal_get_socket() 改为“查找并持有临时引用”，新增 sal_socket_put() 负责释放；
• 将 close/delete 路径改成“先从全局表摘除，再等待 in-flight 引用释放，最后回收/复用对象”的两阶段处理；
• 调整 SAL API 入口以及相关实现层代码，保证使用 struct sal_socket 的整个期间都成对持有/释放引用；
• 扩展 components/net/utest/tc_sal_socket.c，覆盖 close 后继续访问、double close、close/use 竞态、socket cache reuse stress 等回归场景。

该修改不改变正常 socket 路径的接口语义，主要把原先不受约束的关闭/复用竞态收敛为明确、可验证的失败返回和生命周期行为。

请提供验证的bsp和config (provide the config and bsp)

• BSP: bsp/qemu-vexpress-a9

• .config:

  1. 使用 bsp/qemu-vexpress-a9/.config 做基础编译回归验证；
  2. 运行 SAL utest 时，在该 BSP .config 基础上追加：
     • examples/utest/configs/default.cfg
     • examples/utest/configs/components/sal.cfg
     • CONFIG_RT_USING_UTESTCASES=y
     • CONFIG_RT_UTEST_TC_USING_SAL=y

]

当前拉取/合并请求的状态 Intent for your PR

必须选择一项 Choose one (Mandatory):

• 本拉取/合并请求是一个草稿版本 This PR is for a code-review and is intended to get feedback
• 本拉取/合并请求是一个成熟版本 This PR is mature, and ready to be integrated into the repo

代码质量 Code Quality：

我在这个拉取/合并请求中已经考虑了 As part of this pull request, I've considered the following:

• 已经仔细查看过代码改动的对比 Already check the difference between PR and old code
• 代码风格正确，包括缩进空格，命名及其他风格 Style guide is adhered to, including spacing, naming and other styles
• 没有垃圾代码，代码尽量精简，不包含#if 0代码，不包含已经被注释了的代码 All redundant code is removed and cleaned up
• 所有变更均有原因及合理的，并且不会影响到其他软件组件代码或BSP All modifications are justified and not affect other components or BSP
• 对难懂代码均提供对应的注释 I've commented appropriately where code is tricky
• 代码是高质量的 Code in this PR is of high quality
• 已经使用formatting 等源码格式化工具确保格式符合RT-Thread代码规范 This PR complies with RT-Thread code specification
• 如果是新增bsp, 已经添加ci检查到.github/ALL_BSP_COMPILE.json 详细请参考链接BSP自查

[github-actions]

👋 感谢您对 RT-Thread 的贡献！Thank you for your contribution to RT-Thread!

为确保代码符合 RT-Thread 的编码规范，请在你的仓库中执行以下步骤运行代码格式化工作流（如果格式化CI运行失败）。
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• 设置PR number为 \ Set the PR number to：11383

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完成后，提交将自动更新至 fix/sal-socket-lifetime-hardening 分支，关联的 Pull Request 也会同步更新。
Once completed, commits will be pushed to the fix/sal-socket-lifetime-hardening branch automatically, and the related Pull Request will be updated.

如有问题欢迎联系我们，再次感谢您的贡献！💐
If you have any questions, feel free to reach out. Thanks again for your contribution!

[github-actions]

📌 Code Review Assignment

🏷️ Tag: components

Reviewers: Maihuanyi

Changed Files (Click to expand)

• components/net/sal/impl/af_inet_at.c
• components/net/sal/impl/af_inet_lwip.c
• components/net/sal/impl/proto_mbedtls.c
• components/net/sal/include/sal_low_lvl.h
• components/net/sal/src/sal_socket.c
• components/net/utest/tc_sal_socket.c

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📊 Current Review Status (Last Updated: 2026-05-11 23:21 CST)

• ⌛ Maihuanyi Pending Review

---

📝 Review Instructions

1. 维护者可以通过单击此处来刷新审查状态: 🔄 刷新状态
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   Comment LGTM/lgtm after confirming approval

3. PR合并前需至少一位维护者确认
   PR must be confirmed by at least one maintainer before merging

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[Copilot]

Pull request overview

This PR aims to harden RT-Thread SAL (Socket Abstraction Layer) socket lifetime management by introducing an explicit lifecycle + reference counting scheme, and by extending SAL utests to exercise close/reuse and close-vs-use race scenarios.
本 PR 旨在通过引入显式生命周期状态与引用计数来增强 RT-Thread SAL（Socket Abstraction Layer）的 socket 生命周期管理，并扩展 SAL utest 覆盖 close/reuse 以及 close 与使用并发竞争等场景。

Changes:

• Add per-socket lifecycle state + refcount + completion, change sal_get_socket() into “lookup + hold temporary reference”, and introduce sal_socket_put().
  为每个 socket 增加生命周期状态 + 引用计数 + completion，将 sal_get_socket() 改为“查找并持有临时引用”，并新增 sal_socket_put()。
• Rework close/delete paths to detach descriptors from the global table first, then wait for in-flight refs to drain, and finally recycle objects via a cache.
  重构 close/delete 路径：先从全局表摘除，再等待引用释放，最后通过 cache 复用对象。
• Extend SAL utests to verify safe failure after close, double-close behavior, close/use racing, and cache-reuse stress.
  扩展 SAL utest：覆盖 close 后继续访问的安全失败、double close、close/use 竞态，以及 cache 复用压力测试。

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
components/net/sal/src/sal_socket.c	Implements socket refcount/state/completion, updates most SAL APIs to put refs, and reworks close/delete + cache reuse logic.
components/net/sal/include/sal_low_lvl.h	Extends struct sal_socket with lifetime fields and exposes sal_socket_put().
components/net/sal/impl/proto_mbedtls.c	Updates TLS send/recv callbacks to release SAL socket references.
components/net/sal/impl/af_inet_lwip.c	Releases SAL socket reference in lwIP poll path.
components/net/sal/impl/af_inet_at.c	Releases SAL socket reference in AT poll path.
components/net/utest/tc_sal_socket.c	Adds close/reuse stress and close-vs-getsockname race regression tests.

[Telecaster2147]

copilot提出的问题都已解决