On 2/21/23 4:18 AM, D. Wythe wrote:
From: "D. Wythe" <alibuda@xxxxxxxxxxxxxxxxx>
This PATCH adds a tiny selftest for SMC bpf capability,
making decisions on whether to use SMC by collecting
certain information from kernel smc sock.
Follow the steps below to run this test.
make -C tools/testing/selftests/bpf
cd tools/testing/selftests/bpf
sudo ./test_progs -t bpf_smc
Results shows:
18 bpf_smc:OK
Summary: 1/0 PASSED, 0 SKIPPED, 0 FAILED
Signed-off-by: D. Wythe <alibuda@xxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/bpf/prog_tests/bpf_smc.c | 39 +++
tools/testing/selftests/bpf/progs/bpf_smc.c | 315 +++++++++++++++++++++++
2 files changed, 354 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/bpf_smc.c
create mode 100644 tools/testing/selftests/bpf/progs/bpf_smc.c
diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_smc.c b/tools/testing/selftests/bpf/prog_tests/bpf_smc.c
new file mode 100644
index 0000000..b143932
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_smc.c
@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2019 Facebook */
copy-and-paste left-over...
diff --git a/tools/testing/selftests/bpf/progs/bpf_smc.c b/tools/testing/selftests/bpf/progs/bpf_smc.c
new file mode 100644
index 0000000..78c7976
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/bpf_smc.c
@@ -0,0 +1,315 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/bpf.h>
+#include <linux/stddef.h>
+#include <linux/smc.h>
+#include <stdbool.h>
+#include <linux/types.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_core_read.h>
+#include <bpf/bpf_tracing.h>
+
+#define BPF_STRUCT_OPS(name, args...) \
+ SEC("struct_ops/"#name) \
+ BPF_PROG(name, args)
+
+#define SMC_LISTEN (10)
+#define SMC_SOCK_CLOSED_TIMING (0)
+extern unsigned long CONFIG_HZ __kconfig;
+#define HZ CONFIG_HZ
+
+char _license[] SEC("license") = "GPL";
+#define max(a, b) ((a) > (b) ? (a) : (b))
+
+struct sock_common {
+ unsigned char skc_state;
+ __u16 skc_num;
+} __attribute__((preserve_access_index));
+
+struct sock {
+ struct sock_common __sk_common;
+ int sk_sndbuf;
+} __attribute__((preserve_access_index));
+
+struct inet_sock {
+ struct sock sk;
+} __attribute__((preserve_access_index));
+
+struct inet_connection_sock {
+ struct inet_sock icsk_inet;
+} __attribute__((preserve_access_index));
+
+struct tcp_sock {
+ struct inet_connection_sock inet_conn;
+ __u32 rcv_nxt;
+ __u32 snd_nxt;
+ __u32 snd_una;
+ __u32 delivered;
+ __u8 syn_data:1, /* SYN includes data */
+ syn_fastopen:1, /* SYN includes Fast Open option */
+ syn_fastopen_exp:1,/* SYN includes Fast Open exp. option */
+ syn_fastopen_ch:1, /* Active TFO re-enabling probe */
+ syn_data_acked:1,/* data in SYN is acked by SYN-ACK */
+ save_syn:1, /* Save headers of SYN packet */
+ is_cwnd_limited:1,/* forward progress limited by snd_cwnd? */
+ syn_smc:1; /* SYN includes SMC */
+} __attribute__((preserve_access_index));
+
+struct socket {
+ struct sock *sk;
+} __attribute__((preserve_access_index));
All these tcp_sock, socket, inet_sock definitions can go away if it includes
"vmlinux.h". tcp_ca_write_sk_pacing.c is a better example to follow. Try to
define the "common" (eg. tcp, tc...etc) missing macros in bpf_tracing_net.h. The
smc specific macros can stay in this file.
+static inline struct smc_prediction *smc_prediction_get(const struct smc_sock *smc,
+ const struct tcp_sock *tp, __u64 tstamp)
+{
+ struct smc_prediction zero = {}, *smc_predictor;
+ __u16 key;
+ __u32 gap;
+ int err;
+
+ err = bpf_core_read(&key, sizeof(__u16), &tp->inet_conn.icsk_inet.sk.__sk_common.skc_num);
+ if (err)
+ return NULL;
+
+ /* BAD key */
+ if (key == 0)
+ return NULL;
+
+ smc_predictor = bpf_map_lookup_elem(&negotiator_map, &key);
+ if (!smc_predictor) {
+ zero.start_tstamp = bpf_jiffies64();
+ zero.pacing_delta = SMC_PREDICTION_MIN_PACING_DELTA;
+ bpf_map_update_elem(&negotiator_map, &key, &zero, 0);
+ smc_predictor = bpf_map_lookup_elem(&negotiator_map, &key);
+ if (!smc_predictor)
+ return NULL;
+ }
+
+ if (tstamp) {
+ bpf_spin_lock(&smc_predictor->lock);
+ gap = (tstamp - smc_predictor->start_tstamp) / smc_predictor->pacing_delta;
+ /* new splice */
+ if (gap > 0) {
+ smc_predictor->start_tstamp = tstamp;
+ smc_predictor->last_rate_of_lcc =
+ (smc_prediction_calt_rate(smc_predictor) * 7) >> (2 + gap);
+ smc_predictor->closed_long_cc = 0;
+ smc_predictor->closed_total_cc = 0;
+ smc_predictor->incoming_long_cc = 0;
+ }
+ bpf_spin_unlock(&smc_predictor->lock);
+ }
+ return smc_predictor;
+}
+
+/* BPF struct ops for smc protocol negotiator */
+struct smc_sock_negotiator_ops {
+ /* ret for negotiate */
+ int (*negotiate)(struct smc_sock *smc);
+
+ /* info gathering timing */
+ void (*collect_info)(struct smc_sock *smc, int timing);
+};
+
+int BPF_STRUCT_OPS(bpf_smc_negotiate, struct smc_sock *smc)
+{
+ struct smc_prediction *smc_predictor;
+ struct tcp_sock *tp;
+ struct sock *clcsk;
+ int ret = SK_DROP;
+ __u32 rate = 0;
+
+ /* Only make decison during listen */
+ if (smc->sk.__sk_common.skc_state != SMC_LISTEN)
+ return SK_PASS;
+
+ clcsk = BPF_CORE_READ(smc, clcsock, sk);
Instead of using bpf_core_read here, why not directly gets the clcsk like the
'smc->sk.__sk_common.skc_state' above.
+ if (!clcsk)
+ goto error;
+
+ tp = tcp_sk(clcsk);
There is a bpf_skc_to_tcp_sock(). Give it a try after changing the above
BPF_CORE_READ.
+ if (!tp)
+ goto error;
+
+ smc_predictor = smc_prediction_get(smc, tp, bpf_jiffies64());
+ if (!smc_predictor)
+ return SK_PASS;
+
+ bpf_spin_lock(&smc_predictor->lock);
+
+ if (smc_predictor->incoming_long_cc == 0)
+ goto out_locked_pass;
+
+ if (smc_predictor->incoming_long_cc > SMC_PREDICTION_MAX_LONGCC_PER_SPLICE) {
+ ret = 100;
+ goto out_locked_drop;
+ }
+
+ rate = smc_prediction_calt_rate(smc_predictor);
+ if (rate < SMC_PREDICTION_LONGCC_RATE_THRESHOLD) {
+ ret = 200;
+ goto out_locked_drop;
+ }
+out_locked_pass:
+ smc_predictor->incoming_long_cc++;
+ bpf_spin_unlock(&smc_predictor->lock);
+ return SK_PASS;
+out_locked_drop:
+ bpf_spin_unlock(&smc_predictor->lock);
+error:
+ return SK_DROP;
+}
+
+void BPF_STRUCT_OPS(bpf_smc_collect_info, struct smc_sock *smc, int timing)
Try to stay with SEC("struct_ops/...") void BPF_PROG(....)
