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To:     AWilcox@Wilcox-Tech.com
Cc:     netdev@vger.kernel.org, linux-api@vger.kernel.org,
        musl@lists.openwall.com
Subject: Re: [PATCH] uapi: Prevent redefinition of struct iphdr
From:   David Miller <davem@davemloft.net>
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From: "A. Wilcox" <AWilcox@Wilcox-Tech.com>
Date: Sun, 22 Dec 2019 00:02:27 -0600

> @@ -83,6 +83,13 @@
>  
>  #define IPV4_BEET_PHMAXLEN 8
>  
> +/* Allow libcs to deactivate this - musl has its own copy in <netinet/ip.h> */
> +
> +#ifndef __UAPI_DEF_IPHDR
> +#define __UAPI_DEF_IPHDR	1
> +#endif

How is this a musl-only problem?  I see that glibc also defines struct iphdr
in netinet/ip.h, so why doesn't it also suffer from this?

I find it really strange that this, therefore, only happens for musl
and we haven't had thousands of reports of this conflict with glibc
over the years.

I want an explanation, and suitably appropriate adjustments to the commit
message and comments of this change.

Thank you.