net: Retire DCCP socket.

DCCP was orphaned in 2021 by commit 054c4610bd ("MAINTAINERS: dccp: move Gerrit Renker to CREDITS"), which noted that the last maintainer had been inactive for five years. In recent years, it has become a playground for syzbot, and most changes to DCCP have been odd bug fixes triggered by syzbot. Apart from that, the only changes have been driven by treewide or networking API updates or adjustments related to TCP. Thus, in 2023, we announced we would remove DCCP in 2025 via commit b144fcaf46 ("dccp: Print deprecation notice."). Since then, only one individual has contacted the netdev mailing list. [0] There is ongoing research for Multipath DCCP. The repository is hosted on GitHub [1], and development is not taking place through the upstream community. While the repository is published under the GPLv2 license, the scheduling part remains proprietary, with a LICENSE file [2] stating: "This is not Open Source software." The researcher mentioned a plan to address the licensing issue, upstream the patches, and step up as a maintainer, but there has been no further communication since then. Maintaining DCCP for a decade without any real users has become a burden. Therefore, it's time to remove it. Removing DCCP will also provide significant benefits to TCP. It allows us to freely reorganize the layout of struct inet_connection_sock, which is currently shared with DCCP, and optimize it to reduce the number of cachelines accessed in the TCP fast path. Note that we keep DCCP netfilter modules as requested. [3] Link: https://lore.kernel.org/netdev/20230710182253.81446-1-kuniyu@amazon.com/T/#u #[0] Link: https://github.com/telekom/mp-dccp #[1] Link: https://github.com/telekom/mp-dccp/blob/mpdccp_v03_k5.10/net/dccp/non_gpl_scheduler/LICENSE #[2] Link: https://lore.kernel.org/netdev/Z_VQ0KlCRkqYWXa-@calendula/ #[3] Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Acked-by: Paul Moore <paul@paul-moore.com> (LSM and SELinux) Acked-by: Casey Schaufler <casey@schaufler-ca.com> Link: https://patch.msgid.link/20250410023921.11307-3-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2026-11-10 20:48:12 +00:00 · 2025-04-09 19:36:45 -07:00 · 2025-04-09 19:36:45 -07:00 · 2a63dd0edf
commit 2a63dd0edf
parent b2bdce7adc
81 changed files with 14 additions and 14274 deletions
--- a/Documentation/admin-guide/bug-hunting.rst
+++ b/Documentation/admin-guide/bug-hunting.rst
--- a/Documentation/networking/dccp.rst
+++ b/Documentation/networking/dccp.rst
--- a/Documentation/networking/index.rst
+++ b/Documentation/networking/index.rst
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
--- a/Documentation/translations/zh_CN/admin-guide/bug-hunting.rst
+++ b/Documentation/translations/zh_CN/admin-guide/bug-hunting.rst
--- a/Documentation/translations/zh_TW/admin-guide/bug-hunting.rst
+++ b/Documentation/translations/zh_TW/admin-guide/bug-hunting.rst
--- a/9
+++ b/9
--- a/arch/m68k/configs/amiga_defconfig
+++ b/arch/m68k/configs/amiga_defconfig
--- a/arch/m68k/configs/apollo_defconfig
+++ b/arch/m68k/configs/apollo_defconfig
--- a/arch/m68k/configs/atari_defconfig
+++ b/arch/m68k/configs/atari_defconfig
--- a/arch/m68k/configs/bvme6000_defconfig
+++ b/arch/m68k/configs/bvme6000_defconfig
--- a/arch/m68k/configs/hp300_defconfig
+++ b/arch/m68k/configs/hp300_defconfig
--- a/arch/m68k/configs/mac_defconfig
+++ b/arch/m68k/configs/mac_defconfig
--- a/arch/m68k/configs/multi_defconfig
+++ b/arch/m68k/configs/multi_defconfig
--- a/arch/m68k/configs/mvme147_defconfig
+++ b/arch/m68k/configs/mvme147_defconfig
--- a/arch/m68k/configs/mvme16x_defconfig
+++ b/arch/m68k/configs/mvme16x_defconfig
--- a/arch/m68k/configs/q40_defconfig
+++ b/arch/m68k/configs/q40_defconfig
--- a/arch/m68k/configs/sun3_defconfig
+++ b/arch/m68k/configs/sun3_defconfig
--- a/arch/m68k/configs/sun3x_defconfig
+++ b/arch/m68k/configs/sun3x_defconfig
--- a/arch/mips/configs/bigsur_defconfig
+++ b/arch/mips/configs/bigsur_defconfig
--- a/arch/mips/configs/gpr_defconfig
+++ b/arch/mips/configs/gpr_defconfig
--- a/arch/mips/configs/mtx1_defconfig
+++ b/arch/mips/configs/mtx1_defconfig
--- a/arch/powerpc/configs/pmac32_defconfig
+++ b/arch/powerpc/configs/pmac32_defconfig
--- a/arch/powerpc/configs/ppc6xx_defconfig
+++ b/arch/powerpc/configs/ppc6xx_defconfig
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
--- a/include/linux/tfrc.h
+++ b/include/linux/tfrc.h
--- a/include/net/inet_hashtables.h
+++ b/include/net/inet_hashtables.h
--- a/include/net/rstreason.h
+++ b/include/net/rstreason.h
--- a/include/net/secure_seq.h
+++ b/include/net/secure_seq.h
--- a/include/trace/events/sock.h
+++ b/include/trace/events/sock.h
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
--- a/net/Kconfig
+++ b/net/Kconfig
--- a/net/Makefile
+++ b/net/Makefile
--- a/net/core/secure_seq.c
+++ b/net/core/secure_seq.c
--- a/net/core/sock_diag.c
+++ b/net/core/sock_diag.c
--- a/net/dccp/Kconfig
+++ b/net/dccp/Kconfig
--- a/net/dccp/Makefile
+++ b/net/dccp/Makefile
--- a/net/dccp/ackvec.c
+++ b/net/dccp/ackvec.c
--- a/net/dccp/ackvec.h
+++ b/net/dccp/ackvec.h
--- a/net/dccp/ccid.c
+++ b/net/dccp/ccid.c
--- a/net/dccp/ccid.h
+++ b/net/dccp/ccid.h
--- a/net/dccp/ccids/Kconfig
+++ b/net/dccp/ccids/Kconfig
--- a/net/dccp/ccids/ccid2.c
+++ b/net/dccp/ccids/ccid2.c
--- a/net/dccp/ccids/ccid2.h
+++ b/net/dccp/ccids/ccid2.h
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
--- a/net/dccp/ccids/ccid3.h
+++ b/net/dccp/ccids/ccid3.h
--- a/net/dccp/ccids/lib/loss_interval.c
+++ b/net/dccp/ccids/lib/loss_interval.c
--- a/net/dccp/ccids/lib/loss_interval.h
+++ b/net/dccp/ccids/lib/loss_interval.h
--- a/net/dccp/ccids/lib/packet_history.c
+++ b/net/dccp/ccids/lib/packet_history.c
--- a/net/dccp/ccids/lib/packet_history.h
+++ b/net/dccp/ccids/lib/packet_history.h
--- a/net/dccp/ccids/lib/tfrc.c
+++ b/net/dccp/ccids/lib/tfrc.c
--- a/net/dccp/ccids/lib/tfrc.h
+++ b/net/dccp/ccids/lib/tfrc.h
--- a/net/dccp/ccids/lib/tfrc_equation.c
+++ b/net/dccp/ccids/lib/tfrc_equation.c
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
--- a/net/dccp/diag.c
+++ b/net/dccp/diag.c
--- a/net/dccp/feat.c
+++ b/net/dccp/feat.c
--- a/net/dccp/feat.h
+++ b/net/dccp/feat.h
--- a/net/dccp/input.c
+++ b/net/dccp/input.c
--- a/net/dccp/ipv4.c
+++ b/net/dccp/ipv4.c
--- a/net/dccp/ipv6.c
+++ b/net/dccp/ipv6.c
--- a/net/dccp/ipv6.h
+++ b/net/dccp/ipv6.h
--- a/net/dccp/minisocks.c
+++ b/net/dccp/minisocks.c
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
--- a/net/dccp/output.c
+++ b/net/dccp/output.c
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
--- a/net/dccp/qpolicy.c
+++ b/net/dccp/qpolicy.c
--- a/net/dccp/sysctl.c
+++ b/net/dccp/sysctl.c
--- a/net/dccp/timer.c
+++ b/net/dccp/timer.c
--- a/net/dccp/trace.h
+++ b/net/dccp/trace.h
--- a/net/ipv4/Kconfig
+++ b/net/ipv4/Kconfig
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
--- a/samples/bpf/sockex2_kern.c
+++ b/samples/bpf/sockex2_kern.c
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
--- a/security/lsm_audit.c
+++ b/security/lsm_audit.c
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
--- a/security/selinux/include/classmap.h
+++ b/security/selinux/include/classmap.h
--- a/security/selinux/nlmsgtab.c
+++ b/security/selinux/nlmsgtab.c
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c