Date: Mon, 03 Aug 2026 11:28:37 +0000 From: Bruce M Simpson <bms@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: 0e80d9c15deb - main - netinet6: Document IPv4-mapped extension to IPV6_JOIN_GROUP et al. Message-ID: <6a707b65.194b0.2ec6ba1d@gitrepo.freebsd.org>
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The branch main has been updated by bms: URL: https://cgit.FreeBSD.org/src/commit/?id=0e80d9c15debb7438de839aabaa4b6da5c7a3936 commit 0e80d9c15debb7438de839aabaa4b6da5c7a3936 Author: Bruce M Simpson <bms@FreeBSD.org> AuthorDate: 2026-08-01 08:51:28 +0000 Commit: Bruce M Simpson <bms@FreeBSD.org> CommitDate: 2026-08-03 11:27:45 +0000 netinet6: Document IPv4-mapped extension to IPV6_JOIN_GROUP et al. The IPv6 socket options IPV6_JOIN_GROUP and IPV6_LEAVE_GROUP socket options are being extended to accept IPv4 multicast group addresses in the RFC 3493 IPv4-mapped address format as a convenience to application developers. Caveat this addition carefully in the newly added HISTORY section, addressing all previous review comments. Approved by: ziaee Reviewed by: ziaee, glebius PR: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=193246 Differential Revision: https://reviews.freebsd.org/D55382 --- share/man/man4/ip6.4 | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/share/man/man4/ip6.4 b/share/man/man4/ip6.4 index ce756854a47d..fa393e6227ba 100644 --- a/share/man/man4/ip6.4 +++ b/share/man/man4/ip6.4 @@ -28,7 +28,7 @@ .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" -.Dd July 24, 2022 +.Dd August 1, 2026 .Dt IP6 4 .Os .Sh NAME @@ -502,6 +502,16 @@ multicast groups and other multicast options include .Dv IPV6_LEAVE_GROUP , and .Dv IPV6_JOIN_GROUP . +.Pp +In addition, the +.Dv IPV6_JOIN_GROUP , +and +.Dv IPV6_LEAVE_GROUP +socket options will accept IPv4-mapped multicast group +addresses for Any-Source Memberships (ASM) only. +This is an extension to the behaviour for unicast IPv4-mapped +address support described in Section 3.7 of RFC 3493, +which has been adopted by many network applications. .Ss Raw Sockets Raw IPv6 sockets are connectionless and are normally used with the .Xr sendto 2 @@ -729,3 +739,12 @@ The .Dv IPV6_PORTRANGE socket option and the conflict resolution rule are not defined in the RFCs and should be considered implementation dependent. +.Sh HISTORY +The extensions for +.Dv IPV6_JOIN_GROUP +and +.Dv IPV6_LEAVE_GROUP +to accept IPv4 group addresses in RFC 4291 IPv4-mapped format were added in +.Fx 16.0 . +These extensions were never formally defined in RFC 3493, and RFC 4038 did not +define any migration mechanism for multicast groups specified in this way.home | help
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