Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 626 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/progs/test_tcp_hdr_options.c b/tools/testing/selftests/bpf/progs/test_tcp_hdr_options.c
new file mode 100644
index 000000000..5f4e87ee9
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_tcp_hdr_options.c
@@ -0,0 +1,626 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2020 Facebook */
+
+#include <stddef.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <linux/tcp.h>
+#include <linux/socket.h>
+#include <linux/bpf.h>
+#include <linux/types.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_endian.h>
+#define BPF_PROG_TEST_TCP_HDR_OPTIONS
+#include "test_tcp_hdr_options.h"
+
+#ifndef sizeof_field
+#define sizeof_field(TYPE, MEMBER) sizeof((((TYPE *)0)->MEMBER))
+#endif
+
+__u8 test_kind = TCPOPT_EXP;
+__u16 test_magic = 0xeB9F;
+__u32 inherit_cb_flags = 0;
+
+struct bpf_test_option passive_synack_out = {};
+struct bpf_test_option passive_fin_out	= {};
+
+struct bpf_test_option passive_estab_in = {};
+struct bpf_test_option passive_fin_in	= {};
+
+struct bpf_test_option active_syn_out	= {};
+struct bpf_test_option active_fin_out	= {};
+
+struct bpf_test_option active_estab_in	= {};
+struct bpf_test_option active_fin_in	= {};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_SK_STORAGE);
+	__uint(map_flags, BPF_F_NO_PREALLOC);
+	__type(key, int);
+	__type(value, struct hdr_stg);
+} hdr_stg_map SEC(".maps");
+
+static bool skops_want_cookie(const struct bpf_sock_ops *skops)
+{
+	return skops->args[0] == BPF_WRITE_HDR_TCP_SYNACK_COOKIE;
+}
+
+static bool skops_current_mss(const struct bpf_sock_ops *skops)
+{
+	return skops->args[0] == BPF_WRITE_HDR_TCP_CURRENT_MSS;
+}
+
+static __u8 option_total_len(__u8 flags)
+{
+	__u8 i, len = 1; /* +1 for flags */
+
+	if (!flags)
+		return 0;
+
+	/* RESEND bit does not use a byte */
+	for (i = OPTION_RESEND + 1; i < __NR_OPTION_FLAGS; i++)
+		len += !!TEST_OPTION_FLAGS(flags, i);
+
+	if (test_kind == TCPOPT_EXP)
+		return len + TCP_BPF_EXPOPT_BASE_LEN;
+	else
+		return len + 2; /* +1 kind, +1 kind-len */
+}
+
+static void write_test_option(const struct bpf_test_option *test_opt,
+			      __u8 *data)
+{
+	__u8 offset = 0;
+
+	data[offset++] = test_opt->flags;
+	if (TEST_OPTION_FLAGS(test_opt->flags, OPTION_MAX_DELACK_MS))
+		data[offset++] = test_opt->max_delack_ms;
+
+	if (TEST_OPTION_FLAGS(test_opt->flags, OPTION_RAND))
+		data[offset++] = test_opt->rand;
+}
+
+static int store_option(struct bpf_sock_ops *skops,
+			const struct bpf_test_option *test_opt)
+{
+	union {
+		struct tcp_exprm_opt exprm;
+		struct tcp_opt regular;
+	} write_opt;
+	int err;
+
+	if (test_kind == TCPOPT_EXP) {
+		write_opt.exprm.kind = TCPOPT_EXP;
+		write_opt.exprm.len = option_total_len(test_opt->flags);
+		write_opt.exprm.magic = __bpf_htons(test_magic);
+		write_opt.exprm.data32 = 0;
+		write_test_option(test_opt, write_opt.exprm.data);
+		err = bpf_store_hdr_opt(skops, &write_opt.exprm,
+					sizeof(write_opt.exprm), 0);
+	} else {
+		write_opt.regular.kind = test_kind;
+		write_opt.regular.len = option_total_len(test_opt->flags);
+		write_opt.regular.data32 = 0;
+		write_test_option(test_opt, write_opt.regular.data);
+		err = bpf_store_hdr_opt(skops, &write_opt.regular,
+					sizeof(write_opt.regular), 0);
+	}
+
+	if (err)
+		RET_CG_ERR(err);
+
+	return CG_OK;
+}
+
+static int parse_test_option(struct bpf_test_option *opt, const __u8 *start)
+{
+	opt->flags = *start++;
+
+	if (TEST_OPTION_FLAGS(opt->flags, OPTION_MAX_DELACK_MS))
+		opt->max_delack_ms = *start++;
+
+	if (TEST_OPTION_FLAGS(opt->flags, OPTION_RAND))
+		opt->rand = *start++;
+
+	return 0;
+}
+
+static int load_option(struct bpf_sock_ops *skops,
+		       struct bpf_test_option *test_opt, bool from_syn)
+{
+	union {
+		struct tcp_exprm_opt exprm;
+		struct tcp_opt regular;
+	} search_opt;
+	int ret, load_flags = from_syn ? BPF_LOAD_HDR_OPT_TCP_SYN : 0;
+
+	if (test_kind == TCPOPT_EXP) {
+		search_opt.exprm.kind = TCPOPT_EXP;
+		search_opt.exprm.len = 4;
+		search_opt.exprm.magic = __bpf_htons(test_magic);
+		search_opt.exprm.data32 = 0;
+		ret = bpf_load_hdr_opt(skops, &search_opt.exprm,
+				       sizeof(search_opt.exprm), load_flags);
+		if (ret < 0)
+			return ret;
+		return parse_test_option(test_opt, search_opt.exprm.data);
+	} else {
+		search_opt.regular.kind = test_kind;
+		search_opt.regular.len = 0;
+		search_opt.regular.data32 = 0;
+		ret = bpf_load_hdr_opt(skops, &search_opt.regular,
+				       sizeof(search_opt.regular), load_flags);
+		if (ret < 0)
+			return ret;
+		return parse_test_option(test_opt, search_opt.regular.data);
+	}
+}
+
+static int synack_opt_len(struct bpf_sock_ops *skops)
+{
+	struct bpf_test_option test_opt = {};
+	__u8 optlen;
+	int err;
+
+	if (!passive_synack_out.flags)
+		return CG_OK;
+
+	err = load_option(skops, &test_opt, true);
+
+	/* bpf_test_option is not found */
+	if (err == -ENOMSG)
+		return CG_OK;
+
+	if (err)
+		RET_CG_ERR(err);
+
+	optlen = option_total_len(passive_synack_out.flags);
+	if (optlen) {
+		err = bpf_reserve_hdr_opt(skops, optlen, 0);
+		if (err)
+			RET_CG_ERR(err);
+	}
+
+	return CG_OK;
+}
+
+static int write_synack_opt(struct bpf_sock_ops *skops)
+{
+	struct bpf_test_option opt;
+
+	if (!passive_synack_out.flags)
+		/* We should not even be called since no header
+		 * space has been reserved.
+		 */
+		RET_CG_ERR(0);
+
+	opt = passive_synack_out;
+	if (skops_want_cookie(skops))
+		SET_OPTION_FLAGS(opt.flags, OPTION_RESEND);
+
+	return store_option(skops, &opt);
+}
+
+static int syn_opt_len(struct bpf_sock_ops *skops)
+{
+	__u8 optlen;
+	int err;
+
+	if (!active_syn_out.flags)
+		return CG_OK;
+
+	optlen = option_total_len(active_syn_out.flags);
+	if (optlen) {
+		err = bpf_reserve_hdr_opt(skops, optlen, 0);
+		if (err)
+			RET_CG_ERR(err);
+	}
+
+	return CG_OK;
+}
+
+static int write_syn_opt(struct bpf_sock_ops *skops)
+{
+	if (!active_syn_out.flags)
+		RET_CG_ERR(0);
+
+	return store_option(skops, &active_syn_out);
+}
+
+static int fin_opt_len(struct bpf_sock_ops *skops)
+{
+	struct bpf_test_option *opt;
+	struct hdr_stg *hdr_stg;
+	__u8 optlen;
+	int err;
+
+	if (!skops->sk)
+		RET_CG_ERR(0);
+
+	hdr_stg = bpf_sk_storage_get(&hdr_stg_map, skops->sk, NULL, 0);
+	if (!hdr_stg)
+		RET_CG_ERR(0);
+
+	if (hdr_stg->active)
+		opt = &active_fin_out;
+	else
+		opt = &passive_fin_out;
+
+	optlen = option_total_len(opt->flags);
+	if (optlen) {
+		err = bpf_reserve_hdr_opt(skops, optlen, 0);
+		if (err)
+			RET_CG_ERR(err);
+	}
+
+	return CG_OK;
+}
+
+static int write_fin_opt(struct bpf_sock_ops *skops)
+{
+	struct bpf_test_option *opt;
+	struct hdr_stg *hdr_stg;
+
+	if (!skops->sk)
+		RET_CG_ERR(0);
+
+	hdr_stg = bpf_sk_storage_get(&hdr_stg_map, skops->sk, NULL, 0);
+	if (!hdr_stg)
+		RET_CG_ERR(0);
+
+	if (hdr_stg->active)
+		opt = &active_fin_out;
+	else
+		opt = &passive_fin_out;
+
+	if (!opt->flags)
+		RET_CG_ERR(0);
+
+	return store_option(skops, opt);
+}
+
+static int resend_in_ack(struct bpf_sock_ops *skops)
+{
+	struct hdr_stg *hdr_stg;
+
+	if (!skops->sk)
+		return -1;
+
+	hdr_stg = bpf_sk_storage_get(&hdr_stg_map, skops->sk, NULL, 0);
+	if (!hdr_stg)
+		return -1;
+
+	return !!hdr_stg->resend_syn;
+}
+
+static int nodata_opt_len(struct bpf_sock_ops *skops)
+{
+	int resend;
+
+	resend = resend_in_ack(skops);
+	if (resend < 0)
+		RET_CG_ERR(0);
+
+	if (resend)
+		return syn_opt_len(skops);
+
+	return CG_OK;
+}
+
+static int write_nodata_opt(struct bpf_sock_ops *skops)
+{
+	int resend;
+
+	resend = resend_in_ack(skops);
+	if (resend < 0)
+		RET_CG_ERR(0);
+
+	if (resend)
+		return write_syn_opt(skops);
+
+	return CG_OK;
+}
+
+static int data_opt_len(struct bpf_sock_ops *skops)
+{
+	/* Same as the nodata version.  Mostly to show
+	 * an example usage on skops->skb_len.
+	 */
+	return nodata_opt_len(skops);
+}
+
+static int write_data_opt(struct bpf_sock_ops *skops)
+{
+	return write_nodata_opt(skops);
+}
+
+static int current_mss_opt_len(struct bpf_sock_ops *skops)
+{
+	/* Reserve maximum that may be needed */
+	int err;
+
+	err = bpf_reserve_hdr_opt(skops, option_total_len(OPTION_MASK), 0);
+	if (err)
+		RET_CG_ERR(err);
+
+	return CG_OK;
+}
+
+static int handle_hdr_opt_len(struct bpf_sock_ops *skops)
+{
+	__u8 tcp_flags = skops_tcp_flags(skops);
+
+	if ((tcp_flags & TCPHDR_SYNACK) == TCPHDR_SYNACK)
+		return synack_opt_len(skops);
+
+	if (tcp_flags & TCPHDR_SYN)
+		return syn_opt_len(skops);
+
+	if (tcp_flags & TCPHDR_FIN)
+		return fin_opt_len(skops);
+
+	if (skops_current_mss(skops))
+		/* The kernel is calculating the MSS */
+		return current_mss_opt_len(skops);
+
+	if (skops->skb_len)
+		return data_opt_len(skops);
+
+	return nodata_opt_len(skops);
+}
+
+static int handle_write_hdr_opt(struct bpf_sock_ops *skops)
+{
+	__u8 tcp_flags = skops_tcp_flags(skops);
+	struct tcphdr *th;
+
+	if ((tcp_flags & TCPHDR_SYNACK) == TCPHDR_SYNACK)
+		return write_synack_opt(skops);
+
+	if (tcp_flags & TCPHDR_SYN)
+		return write_syn_opt(skops);
+
+	if (tcp_flags & TCPHDR_FIN)
+		return write_fin_opt(skops);
+
+	th = skops->skb_data;
+	if (th + 1 > skops->skb_data_end)
+		RET_CG_ERR(0);
+
+	if (skops->skb_len > tcp_hdrlen(th))
+		return write_data_opt(skops);
+
+	return write_nodata_opt(skops);
+}
+
+static int set_delack_max(struct bpf_sock_ops *skops, __u8 max_delack_ms)
+{
+	__u32 max_delack_us = max_delack_ms * 1000;
+
+	return bpf_setsockopt(skops, SOL_TCP, TCP_BPF_DELACK_MAX,
+			      &max_delack_us, sizeof(max_delack_us));
+}
+
+static int set_rto_min(struct bpf_sock_ops *skops, __u8 peer_max_delack_ms)
+{
+	__u32 min_rto_us = peer_max_delack_ms * 1000;
+
+	return bpf_setsockopt(skops, SOL_TCP, TCP_BPF_RTO_MIN, &min_rto_us,
+			      sizeof(min_rto_us));
+}
+
+static int handle_active_estab(struct bpf_sock_ops *skops)
+{
+	struct hdr_stg init_stg = {
+		.active = true,
+	};
+	int err;
+
+	err = load_option(skops, &active_estab_in, false);
+	if (err && err != -ENOMSG)
+		RET_CG_ERR(err);
+
+	init_stg.resend_syn = TEST_OPTION_FLAGS(active_estab_in.flags,
+						OPTION_RESEND);
+	if (!skops->sk || !bpf_sk_storage_get(&hdr_stg_map, skops->sk,
+					      &init_stg,
+					      BPF_SK_STORAGE_GET_F_CREATE))
+		RET_CG_ERR(0);
+
+	if (init_stg.resend_syn)
+		/* Don't clear the write_hdr cb now because
+		 * the ACK may get lost and retransmit may
+		 * be needed.
+		 *
+		 * PARSE_ALL_HDR cb flag is set to learn if this
+		 * resend_syn option has received by the peer.
+		 *
+		 * The header option will be resent until a valid
+		 * packet is received at handle_parse_hdr()
+		 * and all hdr cb flags will be cleared in
+		 * handle_parse_hdr().
+		 */
+		set_parse_all_hdr_cb_flags(skops);
+	else if (!active_fin_out.flags)
+		/* No options will be written from now */
+		clear_hdr_cb_flags(skops);
+
+	if (active_syn_out.max_delack_ms) {
+		err = set_delack_max(skops, active_syn_out.max_delack_ms);
+		if (err)
+			RET_CG_ERR(err);
+	}
+
+	if (active_estab_in.max_delack_ms) {
+		err = set_rto_min(skops, active_estab_in.max_delack_ms);
+		if (err)
+			RET_CG_ERR(err);
+	}
+
+	return CG_OK;
+}
+
+static int handle_passive_estab(struct bpf_sock_ops *skops)
+{
+	struct hdr_stg init_stg = {};
+	struct tcphdr *th;
+	int err;
+
+	inherit_cb_flags = skops->bpf_sock_ops_cb_flags;
+
+	err = load_option(skops, &passive_estab_in, true);
+	if (err == -ENOENT) {
+		/* saved_syn is not found. It was in syncookie mode.
+		 * We have asked the active side to resend the options
+		 * in ACK, so try to find the bpf_test_option from ACK now.
+		 */
+		err = load_option(skops, &passive_estab_in, false);
+		init_stg.syncookie = true;
+	}
+
+	/* ENOMSG: The bpf_test_option is not found which is fine.
+	 * Bail out now for all other errors.
+	 */
+	if (err && err != -ENOMSG)
+		RET_CG_ERR(err);
+
+	th = skops->skb_data;
+	if (th + 1 > skops->skb_data_end)
+		RET_CG_ERR(0);
+
+	if (th->syn) {
+		/* Fastopen */
+
+		/* Cannot clear cb_flags to stop write_hdr cb.
+		 * synack is not sent yet for fast open.
+		 * Even it was, the synack may need to be retransmitted.
+		 *
+		 * PARSE_ALL_HDR cb flag is set to learn
+		 * if synack has reached the peer.
+		 * All cb_flags will be cleared in handle_parse_hdr().
+		 */
+		set_parse_all_hdr_cb_flags(skops);
+		init_stg.fastopen = true;
+	} else if (!passive_fin_out.flags) {
+		/* No options will be written from now */
+		clear_hdr_cb_flags(skops);
+	}
+
+	if (!skops->sk ||
+	    !bpf_sk_storage_get(&hdr_stg_map, skops->sk, &init_stg,
+				BPF_SK_STORAGE_GET_F_CREATE))
+		RET_CG_ERR(0);
+
+	if (passive_synack_out.max_delack_ms) {
+		err = set_delack_max(skops, passive_synack_out.max_delack_ms);
+		if (err)
+			RET_CG_ERR(err);
+	}
+
+	if (passive_estab_in.max_delack_ms) {
+		err = set_rto_min(skops, passive_estab_in.max_delack_ms);
+		if (err)
+			RET_CG_ERR(err);
+	}
+
+	return CG_OK;
+}
+
+static int handle_parse_hdr(struct bpf_sock_ops *skops)
+{
+	struct hdr_stg *hdr_stg;
+	struct tcphdr *th;
+
+	if (!skops->sk)
+		RET_CG_ERR(0);
+
+	th = skops->skb_data;
+	if (th + 1 > skops->skb_data_end)
+		RET_CG_ERR(0);
+
+	hdr_stg = bpf_sk_storage_get(&hdr_stg_map, skops->sk, NULL, 0);
+	if (!hdr_stg)
+		RET_CG_ERR(0);
+
+	if (hdr_stg->resend_syn || hdr_stg->fastopen)
+		/* The PARSE_ALL_HDR cb flag was turned on
+		 * to ensure that the previously written
+		 * options have reached the peer.
+		 * Those previously written option includes:
+		 *     - Active side: resend_syn in ACK during syncookie
+		 *      or
+		 *     - Passive side: SYNACK during fastopen
+		 *
+		 * A valid packet has been received here after
+		 * the 3WHS, so the PARSE_ALL_HDR cb flag
+		 * can be cleared now.
+		 */
+		clear_parse_all_hdr_cb_flags(skops);
+
+	if (hdr_stg->resend_syn && !active_fin_out.flags)
+		/* Active side resent the syn option in ACK
+		 * because the server was in syncookie mode.
+		 * A valid packet has been received, so
+		 * clear header cb flags if there is no
+		 * more option to send.
+		 */
+		clear_hdr_cb_flags(skops);
+
+	if (hdr_stg->fastopen && !passive_fin_out.flags)
+		/* Passive side was in fastopen.
+		 * A valid packet has been received, so
+		 * the SYNACK has reached the peer.
+		 * Clear header cb flags if there is no more
+		 * option to send.
+		 */
+		clear_hdr_cb_flags(skops);
+
+	if (th->fin) {
+		struct bpf_test_option *fin_opt;
+		int err;
+
+		if (hdr_stg->active)
+			fin_opt = &active_fin_in;
+		else
+			fin_opt = &passive_fin_in;
+
+		err = load_option(skops, fin_opt, false);
+		if (err && err != -ENOMSG)
+			RET_CG_ERR(err);
+	}
+
+	return CG_OK;
+}
+
+SEC("sockops")
+int estab(struct bpf_sock_ops *skops)
+{
+	int true_val = 1;
+
+	switch (skops->op) {
+	case BPF_SOCK_OPS_TCP_LISTEN_CB:
+		bpf_setsockopt(skops, SOL_TCP, TCP_SAVE_SYN,
+			       &true_val, sizeof(true_val));
+		set_hdr_cb_flags(skops, BPF_SOCK_OPS_STATE_CB_FLAG);
+		break;
+	case BPF_SOCK_OPS_TCP_CONNECT_CB:
+		set_hdr_cb_flags(skops, 0);
+		break;
+	case BPF_SOCK_OPS_PARSE_HDR_OPT_CB:
+		return handle_parse_hdr(skops);
+	case BPF_SOCK_OPS_HDR_OPT_LEN_CB:
+		return handle_hdr_opt_len(skops);
+	case BPF_SOCK_OPS_WRITE_HDR_OPT_CB:
+		return handle_write_hdr_opt(skops);
+	case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB:
+		return handle_passive_estab(skops);
+	case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB:
+		return handle_active_estab(skops);
+	}
+
+	return CG_OK;
+}
+
+char _license[] SEC("license") = "GPL";