On 2025-01-16 15:44:39, D. Wythe wrote:
>The introduction of IPPROTO_SMC enables eBPF programs to determine
>whether to use SMC based on the context of socket creation, such as
>network namespaces, PID and comm name, etc.
>
>As a subsequent enhancement, to introduce a new generic hook that
>allows decisions on whether to use SMC or not at runtime, including
>but not limited to local/remote IP address or ports.
>
>Moreover, in the future, we can achieve more complex extensions to the
>protocol stack by extending this ops.
>
>Signed-off-by: D. Wythe <alibuda@xxxxxxxxxxxxxxxxx>
>---
> include/net/netns/smc.h | 3 ++
> include/net/smc.h | 53 +++++++++++++++++++++++
> net/ipv4/tcp_output.c | 18 ++++++--
> net/smc/Kconfig | 12 ++++++
> net/smc/Makefile | 1 +
> net/smc/smc_ops.c | 53 +++++++++++++++++++++++
> net/smc/smc_ops.h | 28 ++++++++++++
> net/smc/smc_sysctl.c | 94 +++++++++++++++++++++++++++++++++++++++++
> 8 files changed, 258 insertions(+), 4 deletions(-)
> create mode 100644 net/smc/smc_ops.c
> create mode 100644 net/smc/smc_ops.h
>
>diff --git a/include/net/netns/smc.h b/include/net/netns/smc.h
>index fc752a50f91b..81b3fdb39cd2 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_OPS)
>+ struct smc_ops __rcu *ops;
>+#endif /* CONFIG_SMC_OPS */
> 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 db84e4e35080..271838591b63 100644
>--- a/include/net/smc.h
>+++ b/include/net/smc.h
>@@ -18,6 +18,8 @@
> #include "linux/ism.h"
>
> struct sock;
>+struct tcp_sock;
>+struct inet_request_sock;
>
> #define SMC_MAX_PNETID_LEN 16 /* Max. length of PNET id */
>
>@@ -97,4 +99,55 @@ struct smcd_dev {
> u8 going_away : 1;
> };
>
>+#define SMC_OPS_NAME_MAX 16
>+
>+enum {
>+ /* ops can be inherit from init_net */
>+ SMC_OPS_FLAG_INHERITABLE = 0x1,
>+
>+ SMC_OPS_ALL_FLAGS = SMC_OPS_FLAG_INHERITABLE,
>+};
>+
>+struct smc_ops {
>+ /* priavte */
>+
>+ struct list_head list;
>+ struct module *owner;
>+
>+ /* public */
>+
>+ /* unique name */
>+ char name[SMC_OPS_NAME_MAX];
>+ int flags;
>+
>+ /* Invoked before computing SMC option for SYN packets.
>+ * We can control whether to set SMC options by returning varios value.
>+ * Return 0 to disable SMC, or return any other value to enable it.
>+ */
>+ int (*set_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 varios
>+ * value. Return 0 to disable SMC, or return any other value to enable
>+ * it.
>+ */
>+ int (*set_option_cond)(const struct tcp_sock *tp,
>+ struct inet_request_sock *ireq);
>+};
>+
>+#if IS_ENABLED(CONFIG_SMC_OPS)
>+#define smc_call_retops(init_val, sk, func, ...) ({ \
>+ typeof(init_val) __ret = (init_val); \
>+ struct smc_ops *ops; \
>+ rcu_read_lock(); \
>+ ops = READ_ONCE(sock_net(sk)->smc.ops); \
>+ if (ops && ops->func) \
>+ __ret = ops->func(__VA_ARGS__); \
>+ rcu_read_unlock(); \
>+ !!__ret; \
>+})
Here you force the return value to be bool by !!ret, what if the
future caller expects the return value to be an integer or other types ?
Best regards,
Dust
