From nobody Fri Apr 26 20:49:03 2024 X-Original-To: freebsd-net@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4VR4Zp62K8z5JCC8 for ; Fri, 26 Apr 2024 20:49:06 +0000 (UTC) (envelope-from mike@karels.net) Received: from mail2.karels.net (mail2.karels.net [3.19.118.201]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (2048 bits) client-digest SHA256) (Client CN "freebsd", Issuer "freebsd" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4VR4Zp4KKNz4Dwr for ; Fri, 26 Apr 2024 20:49:06 +0000 (UTC) (envelope-from mike@karels.net) Authentication-Results: mx1.freebsd.org; none Received: from mail2.karels.net (localhost [IPv6:0:0:0:0:0:0:0:1]) by mail2.karels.net (8.18.1/8.18.1) with ESMTP id 43QKn4Wv084310; Fri, 26 Apr 2024 15:49:04 -0500 (CDT) (envelope-from mike@karels.net) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=karels.net; s=mail2; t=1714164544; bh=BHLuvtOLPF37qr2kp+DlNSYzpHpBfGNRA6LRLLgxFMQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Ubh54cdNZv36lveon4Vrz/9QIb7MYNdHNnPClj+juGCYxBHeFKQgx7hQsT6xlhQh/ gwZn6aldF4BGYfeMJ9P9Zk1i3J2mrcm8xYTMtSk6KmTDu1h8cgj1nPJYIBX4TdeCx4 HyeW9u5XVKKr8ZvhSEwh5e0hmMdHG1h9nSPYwVsEIQOjAa1AoT/xrUDyj6IRWjZRsz uybXKizRVqztVkPZRFmoRcxOTRrhaZME5FSS95qaJUKvPxts+Men6iycZemNCcWW3O vHPcjRsoC5O46RM20HfEc4/kwuwfQpJK628hYpfzd7/3271Ikpet9Whx0HkMoEUtAx 5N1NQqal6Ne/g== Received: from [10.0.2.130] ([73.62.165.147]) by mail2.karels.net with ESMTPSA id CkgQGEATLGZUSQEAs/W3XQ (envelope-from ); Fri, 26 Apr 2024 15:49:04 -0500 From: Mike Karels To: Warner Losh Cc: FreeBSD Net Subject: Re: Question about netinet6/in6.h Date: Fri, 26 Apr 2024 15:49:03 -0500 X-Mailer: MailMate (1.14r6028) Message-ID: <229EB3F8-FB68-461C-BF1F-3B2846510EBA@karels.net> In-Reply-To: References: List-Id: Networking and TCP/IP with FreeBSD List-Archive: https://lists.freebsd.org/archives/freebsd-net List-Help: List-Post: List-Subscribe: List-Unsubscribe: Sender: owner-freebsd-net@FreeBSD.org MIME-Version: 1.0 Content-Type: text/plain X-Spamd-Bar: ---- X-Rspamd-Pre-Result: action=no action; module=replies; Message is reply to one we originated X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[]; ASN(0.00)[asn:16509, ipnet:3.16.0.0/14, country:US] X-Rspamd-Queue-Id: 4VR4Zp4KKNz4Dwr On 26 Apr 2024, at 15:01, Warner Losh wrote: > This has to be a FAQ > > I'm porting a program from Linux, I often see an error like: > ./test/mock-ifaddrs.c:95:19: error: no member named 's6_addr32' in 'struct > in6_addr' > 95 | ipv6->sin6_addr.s6_addr32[3] = 0; > | ~~~~~~~~~~~~~~~ ^ > but yet, we kinda define them, but only for the kernel and boot loader: > /* > * IPv6 address > */ > struct in6_addr { > union { > uint8_t __u6_addr8[16]; > uint16_t __u6_addr16[8]; > uint32_t __u6_addr32[4]; > } __u6_addr; /* 128-bit IP6 address */ > }; > > #define s6_addr __u6_addr.__u6_addr8 > #if defined(_KERNEL) || defined(_STANDALONE) /* XXX nonstandard */ > #define s6_addr8 __u6_addr.__u6_addr8 > #define s6_addr16 __u6_addr.__u6_addr16 > #define s6_addr32 __u6_addr.__u6_addr32 > #endif > > I'm wondering if anybody why it's like that? git blame suggests we imported > that from kame, with > only tweaks by people that are now deceased*.* > > Why not just expose them? Looks like only s6_addr is specified in the RFCs (2553 and 3493). Oddly, though, the RFCs give an example implementation using that union with different element names (like _S6_u8), and show the one #define. Similarly, POSIX specifies only s6_addr, but it allows other members of the structure, so I don't see a problem with exposing them all even in a POSIX environment. I would have no objection to exposing all four definitions, especially if Linux apps use them. Mike