[PATCH v2 0/4] ipvs: add per-service secure_tcp

IPVS currently exposes secure_tcp as a per-netns sysctl. It switches the
TCP state machine to the hardened tcp_states_dos table.

These patches make it per-service: a virtual service can set
IP_VS_SVC_F_SECURE_TCP which is passed into IP_VS_CONN_F_SECURE_TCP at
connection creation. set_tcp_state() then selects tcp_states_dos for those
connections with IP_VS_CONN_F_SECURE_TCP set and keeps pd->tcp_state_table
(the netns default, including the nomem floor) otherwise.

  1. uapi: define the per-service secure_tcp flags
  2. stamp the flag in ip_vs_bind_dest() (cache-bypass has no dest)
  3. honor it in the TCP state machine, resolving the stale FIXME
  4. kselftest contrasting a secure vs. a plain service

Changes in v2:
- Let IP_VS_SVC_F_SECURE_TCP be 0x0100, leaving 0x0040/0x0080 for the
  scheduler flags. Let IP_VS_CONN_F_SECURE_TCP be (1 << 17) and no longer
  in IP_VS_CONN_F_BACKUP_MASK.
- Set flag in ip_vs_bind_dest() instead of at every ip_vs_conn_new()
  call site.
- selftest: send probes with TTL=1 instead of an nft drop, and fix
  Sashiko comments.

Not sure about patch 4... could be dropped or absorbed into ipvs.sh

Adriano Cordova (4):
  ipvs: add flags for per-service secure TCP state table
  ipvs: stamp per-service secure_tcp on connections
  ipvs: tcp: enable per-connection secure_tcp in state machine
  selftests: netfilter: ipvs: add per-service secure_tcp test

 include/uapi/linux/ip_vs.h                    |   2 +
 net/netfilter/ipvs/ip_vs_conn.c               |   4 +
 net/netfilter/ipvs/ip_vs_core.c               |   3 +
 net/netfilter/ipvs/ip_vs_proto_tcp.c          |  16 +-
 .../testing/selftests/net/netfilter/Makefile  |   6 +
 .../selftests/net/netfilter/gen_tcp_probe.c   | 141 ++++++++
 .../net/netfilter/ipvs_secure_tcp.sh          | 153 +++++++++
 .../net/netfilter/ipvs_secure_tcp_mln.c       | 323 ++++++++++++++++++
 8 files changed, 641 insertions(+), 7 deletions(-)
 create mode 100644 tools/testing/selftests/net/netfilter/gen_tcp_probe.c
 create mode 100755 tools/testing/selftests/net/netfilter/ipvs_secure_tcp.sh
 create mode 100644 tools/testing/selftests/net/netfilter/ipvs_secure_tcp_mln.c

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2.51.0