From nobody Sat Apr 27 00:02:19 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 4VR8ss36czz5JW8P for ; Sat, 27 Apr 2024 00:02:25 +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 4VR8sr54cLz4X7r for ; Sat, 27 Apr 2024 00:02:24 +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 43R02K3B085198; Fri, 26 Apr 2024 19:02:20 -0500 (CDT) (envelope-from mike@karels.net) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=karels.net; s=mail2; t=1714176140; bh=/G9EJmLmIpBQPTzAZh/Ka4xrr9dKD/stgt7uSjyOoaM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Pitc3RtlfeU2UKfmQ4T0lvIr6OYe3KxCnfvKYpmz8W99syezs6C4BIgqj80Y56vOY RVzmODzLZD8lh88QoKp44mMu7eamvkwHJoDpiFBytWGMMpp9U4ampuFPdI7BX/PYlC V57P4V8OY4U9nlM1KUYh4fZ4enkTXAXST7UNb9wGWOfKeatCOAFKmsLIQyLcszS68H vePODZzB9xabIaE+FWjf4ZFnDf7duUV48w5Y1t2jqnxOSwnPt7lcIa5yMTgAhhjV3s GE6XPgR+fE6eOjnzm+2DXLBtpJ1arFKHwifjNKvdK3+BLYUb8tpdcinQIGp3Aww9O9 LefHE5dBe1+3A== Received: from [10.0.2.130] ([73.62.165.147]) by mail2.karels.net with ESMTPSA id LbHkKYxALGbMTAEAs/W3XQ (envelope-from ); Fri, 26 Apr 2024 19:02:20 -0500 From: Mike Karels To: Warner Losh Cc: FreeBSD Net Subject: Re: Question about netinet6/in6.h Date: Fri, 26 Apr 2024 19:02:19 -0500 X-Mailer: MailMate (1.14r6028) Message-ID: <4AF50212-9141-44FF-937F-A06AF8B15121@karels.net> In-Reply-To: References: <229EB3F8-FB68-461C-BF1F-3B2846510EBA@karels.net> 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; charset=UTF-8 Content-Transfer-Encoding: 8bit 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: 4VR8sr54cLz4X7r On 26 Apr 2024, at 18:06, Warner Losh wrote: > On Fri, Apr 26, 2024 at 4:21 PM Mike Karels wrote: > >> On 26 Apr 2024, at 15:49, Mike Karels wrote: >> >>> 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. >> >> I put the change, along with an explanatory comment, in >> https://reviews.freebsd.org/D44979. Comments welcome. >> > > Thanks! I was testing a similar change, but I like yours better... though > maybe > we should just make it visible when __BSD_VISIBLE is true.... I'll have to > look > closely at what Linux does here... I think they have it always visible, or > at least > musl does that (glibc is harder to track down due to the many layers of > indirection). I thought briefly about __BSD_VISIBLE, but wasn't sure it was necessary. Let me know what you find out. I think it should work either way; in.h includes cdefs.h, so it's guaranteed to have been included. Mike