sys/socket: fix struct sockaddr_storage alignment issue #14595
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the size of struct sockaddr_storage due to struct alignment
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Size: XS
| @@ -327,7 +327,7 @@ struct sockaddr_storage | |||
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| /* Following fields are implementation-defined */ | |||
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| struct | |||
| struct __attribute__((packed)) | |||
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@nuttxs please replace with begin_packed_struct/end_packed_struct
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@xiaoxiang781216 what is the advance of begin/end_packed_struct over attribute((packed)) ?
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__attribute__((packed)) is gcc specific extension, other compiler(e.g. msvc) doesn't support it at all. @lupyuen could we restore some Windows ci now?
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@xiaoxiang781216 I'm already running the Mirrored Builds twice every day, why don't we use it? https://github.com/NuttX/nuttx/actions/runs/11630100298
@nuttxs To verify the Windows Build on your own NuttX Repo, please follow the steps in "To Run Windows Jobs" thanks!
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@xiaoxiang781216 I'm already running the Mirrored Builds twice every day, why don't we use it? https://github.com/NuttX/nuttx/actions/runs/11630100298
@nuttxs To verify the Windows Build on your own NuttX Repo, please follow the steps in "To Run Windows Jobs" thanks!
But it's too late, it's better to catch the error before merging. Please restore one macOS, Windows and msys2 to ci if we have the free quota. If no free quota is available, it's better to remove some Ubuntu ARM build from CI to bring back them.
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@xiaoxiang781216 Let's discuss here thanks!
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@xiaoxiang781216
My apologies for the late response. I noticed that you have already submitted a pull request (PR#14608) addressing the compatibility of __attribute__((packed)) for MSVC.
By the way, does MSVC support the __attribute__((aligned(n))) attribute or keyword? I couldn't find the corresponding definition in compiler.h, and Nuttx makes extensive use of __attribute__((aligned(n))) for alignment.
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Thanks @nuttxs! We have a newer guide here:
Summary
sys/socket: use attribute((packed)) to avoid changes in the size of struct sockaddr_storage due to struct alignment.
Referencing RFC 2553#section-3.10 and the POSIX standard documentation.
Defines the maximum size of the structure, which is typically 128 bytes. But the current output structure size (sizeof(struct sockaddr_storage)) is 136, which does not match this.
This discrepancy can also lead to the following potential issues:
1.An increase in the .bss segment size.
2.Functions may experience alignment issues, such as getifaddrs(&ifap) being unable to read the correct IP address.
The data passed to struct sockaddr_in is shifted, causing incorrect address parsing.
Impact
Testing
Testing with ESP32/ESP32S3 and sim.