Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next

Martin KaFai Lau says:

====================
pull-request: bpf-next 2025-11-10

We've added 19 non-merge commits during the last 3 day(s) which contain
a total of 22 files changed, 1345 insertions(+), 197 deletions(-).

The main changes are:

1) Preserve skb metadata after a TC BPF program has changed the skb,
   from Jakub Sitnicki.
   This allows a TC program at the end of a TC filter chain to still see
   the skb metadata, even if another TC program at the front of the chain
   has changed the skb using BPF helpers.

2) Initial af_smc bpf_struct_ops support to control the smc specific
   syn/synack options, from D. Wythe.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next:
  bpf/selftests: Add selftest for bpf_smc_hs_ctrl
  net/smc: bpf: Introduce generic hook for handshake flow
  bpf: Export necessary symbols for modules with struct_ops
  selftests/bpf: Cover skb metadata access after bpf_skb_change_proto
  selftests/bpf: Cover skb metadata access after change_head/tail helper
  selftests/bpf: Cover skb metadata access after bpf_skb_adjust_room
  selftests/bpf: Cover skb metadata access after vlan push/pop helper
  selftests/bpf: Expect unclone to preserve skb metadata
  selftests/bpf: Dump skb metadata on verification failure
  selftests/bpf: Verify skb metadata in BPF instead of userspace
  bpf: Make bpf_skb_change_head helper metadata-safe
  bpf: Make bpf_skb_change_proto helper metadata-safe
  bpf: Make bpf_skb_adjust_room metadata-safe
  bpf: Make bpf_skb_vlan_push helper metadata-safe
  bpf: Make bpf_skb_vlan_pop helper metadata-safe
  vlan: Make vlan_remove_tag return nothing
  bpf: Unclone skb head on bpf_dynptr_write to skb metadata
  net: Preserve metadata on pskb_expand_head
  net: Helper to move packet data and metadata after skb_push/pull
====================

Link: https://patch.msgid.link/20251110232427.3929291-1-martin.lau@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

2 files changed, 56 insertions, 0 deletions

diff --git a/include/net/netns/smc.h b/include/net/netns/smc.h
index 6ceb12baec24..ed24c9f638ee 100644
--- a/include/net/netns/smc.h
+++ b/include/net/netns/smc.h
@@ -17,6 +17,9 @@ struct netns_smc {
 #ifdef CONFIG_SYSCTL
 	struct ctl_table_header		*smc_hdr;
 #endif
+#if IS_ENABLED(CONFIG_SMC_HS_CTRL_BPF)
+	struct smc_hs_ctrl __rcu	*hs_ctrl;
+#endif /* CONFIG_SMC_HS_CTRL_BPF */
 	unsigned int			sysctl_autocorking_size;
 	unsigned int			sysctl_smcr_buf_type;
 	int				sysctl_smcr_testlink_time;
diff --git a/include/net/smc.h b/include/net/smc.h
index 08bee529ed8d..bfdc4c41f019 100644
--- a/include/net/smc.h
+++ b/include/net/smc.h
@@ -17,6 +17,8 @@
 #include <linux/wait.h>
 #include <linux/dibs.h>
 
+struct tcp_sock;
+struct inet_request_sock;
 struct sock;
 
 #define SMC_MAX_PNETID_LEN	16	/* Max. length of PNET id */
@@ -50,4 +52,55 @@ struct smcd_dev {
 	u8 going_away : 1;
 };
 
+#define SMC_HS_CTRL_NAME_MAX 16
+
+enum {
+	/* ops can be inherit from init_net */
+	SMC_HS_CTRL_FLAG_INHERITABLE = 0x1,
+
+	SMC_HS_CTRL_ALL_FLAGS = SMC_HS_CTRL_FLAG_INHERITABLE,
+};
+
+struct smc_hs_ctrl {
+	/* private */
+
+	struct list_head list;
+	struct module *owner;
+
+	/* public */
+
+	/* unique name */
+	char name[SMC_HS_CTRL_NAME_MAX];
+	int flags;
+
+	/* Invoked before computing SMC option for SYN packets.
+	 * We can control whether to set SMC options by returning various value.
+	 * Return 0 to disable SMC, or return any other value to enable it.
+	 */
+	int (*syn_option)(struct tcp_sock *tp);
+
+	/* Invoked before Set up SMC options for SYN-ACK packets
+	 * We can control whether to respond SMC options by returning various
+	 * value. Return 0 to disable SMC, or return any other value to enable
+	 * it.
+	 */
+	int (*synack_option)(const struct tcp_sock *tp,
+			     struct inet_request_sock *ireq);
+};
+
+#if IS_ENABLED(CONFIG_SMC_HS_CTRL_BPF)
+#define smc_call_hsbpf(init_val, tp, func, ...) ({				\
+	typeof(init_val) __ret = (init_val);					\
+	struct smc_hs_ctrl *ctrl;						\
+	rcu_read_lock();							\
+	ctrl = rcu_dereference(sock_net((struct sock *)(tp))->smc.hs_ctrl);	\
+	if (ctrl && ctrl->func)							\
+		__ret = ctrl->func(tp, ##__VA_ARGS__);				\
+	rcu_read_unlock();							\
+	__ret;									\
+})
+#else
+#define smc_call_hsbpf(init_val, tp, ...)  ({ (void)(tp); (init_val); })
+#endif /* CONFIG_SMC_HS_CTRL_BPF */
+
 #endif	/* _SMC_H */