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Mon, 26 Aug 2024 18:39:13 -0700 (PDT) Received: from n191-036-066.byted.org ([147.160.184.150]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-454fe1c5711sm48263401cf.82.2024.08.26.18.39.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 26 Aug 2024 18:39:13 -0700 (PDT) From: zijianzhang@bytedance.com To: bpf@vger.kernel.org Cc: edumazet@google.com, davem@davemloft.net, kuba@kernel.org, pabeni@redhat.com, dsahern@kernel.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, mykolal@fb.com, shuah@kernel.org, xiyou.wangcong@gmail.com, wangdongdong.6@bytedance.com, zhoufeng.zf@bytedance.com, Amery Hung , Zijian Zhang Subject: [PATCH bpf-next v2 2/2] bpf: selftests: reserve smaller tcp header options than the actual size Date: Tue, 27 Aug 2024 01:37:36 +0000 Message-Id: <20240827013736.2845596-3-zijianzhang@bytedance.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20240827013736.2845596-1-zijianzhang@bytedance.com> References: <20240827013736.2845596-1-zijianzhang@bytedance.com> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: bpf@iogearbox.net From: Amery Hung If eBPF users mistakenly reserve smaller header options than the actual size in BPF_SOCK_OPS_HDR_OPT_LEN_CB, bpf_reserve_hdr_opt should return an appropriate error value, and there will be no packet dropping. Signed-off-by: Zijian Zhang Signed-off-by: Amery Hung --- .../bpf/prog_tests/tcp_hdr_options.c | 51 +++++++++++++ .../bpf/progs/test_reserve_tcp_hdr_options.c | 71 +++++++++++++++++++ 2 files changed, 122 insertions(+) create mode 100644 tools/testing/selftests/bpf/progs/test_reserve_tcp_hdr_options.c diff --git a/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c b/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c index 56685fc03c7e..9c250b5bf00a 100644 --- a/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c +++ b/tools/testing/selftests/bpf/prog_tests/tcp_hdr_options.c @@ -14,6 +14,7 @@ #include "test_tcp_hdr_options.h" #include "test_tcp_hdr_options.skel.h" #include "test_misc_tcp_hdr_options.skel.h" +#include "test_reserve_tcp_hdr_options.skel.h" #define LO_ADDR6 "::1" #define CG_NAME "/tcpbpf-hdr-opt-test" @@ -25,6 +26,7 @@ static struct bpf_test_option exp_active_fin_in; static struct hdr_stg exp_passive_hdr_stg; static struct hdr_stg exp_active_hdr_stg = { .active = true, }; +static struct test_reserve_tcp_hdr_options *reserve_skel; static struct test_misc_tcp_hdr_options *misc_skel; static struct test_tcp_hdr_options *skel; static int lport_linum_map_fd; @@ -513,6 +515,49 @@ static void misc(void) bpf_link__destroy(link); } +static void reserve_hdr_opt(void) +{ + struct bpf_link *link; + struct sk_fds sk_fds; + char send_msg[1500]; + char recv_msg[sizeof(send_msg)]; + int ret; + + if (!ASSERT_OK(system("ip link set dev lo mtu 1500"), "set dev lo mtu to 1500")) + return; + + lport_linum_map_fd = bpf_map__fd(reserve_skel->maps.lport_linum_map); + + link = bpf_program__attach_cgroup(reserve_skel->progs.reserve_tcp_hdr_options, cg_fd); + if (!ASSERT_OK_PTR(link, "attach_cgroup(reserve_tcp_hdr_options)")) + return; + + if (sk_fds_connect(&sk_fds, false)) { + bpf_link__destroy(link); + return; + } + + ret = send(sk_fds.active_fd, send_msg, sizeof(send_msg), + MSG_EOR); + if (!ASSERT_EQ(ret, sizeof(send_msg), "send(msg)")) + goto check_linum; + + ret = read(sk_fds.passive_fd, recv_msg, sizeof(recv_msg)); + if (!ASSERT_EQ(ret, sizeof(send_msg), "read(msg)")) + goto check_linum; + + if (sk_fds_shutdown(&sk_fds)) + goto check_linum; + + ASSERT_FALSE(reserve_skel->bss->nr_err_reserve, "unexpected nr_err_reserve"); + ASSERT_TRUE(reserve_skel->bss->nr_nospc, "unexpected nr_nospc"); + +check_linum: + ASSERT_FALSE(check_error_linum(&sk_fds), "check_error_linum"); + sk_fds_close(&sk_fds); + bpf_link__destroy(link); +} + struct test { const char *desc; void (*run)(void); @@ -526,6 +571,7 @@ static struct test tests[] = { DEF_TEST(fastopen_estab), DEF_TEST(fin), DEF_TEST(misc), + DEF_TEST(reserve_hdr_opt), }; void test_tcp_hdr_options(void) @@ -540,6 +586,10 @@ void test_tcp_hdr_options(void) if (!ASSERT_OK_PTR(misc_skel, "open and load misc test skel")) goto skel_destroy; + reserve_skel = test_reserve_tcp_hdr_options__open_and_load(); + if (!ASSERT_OK_PTR(reserve_skel, "open and load reserve test skel")) + goto skel_destroy; + cg_fd = test__join_cgroup(CG_NAME); if (!ASSERT_GE(cg_fd, 0, "join_cgroup")) goto skel_destroy; @@ -558,6 +608,7 @@ void test_tcp_hdr_options(void) close(cg_fd); skel_destroy: + test_reserve_tcp_hdr_options__destroy(reserve_skel); test_misc_tcp_hdr_options__destroy(misc_skel); test_tcp_hdr_options__destroy(skel); } diff --git a/tools/testing/selftests/bpf/progs/test_reserve_tcp_hdr_options.c b/tools/testing/selftests/bpf/progs/test_reserve_tcp_hdr_options.c new file mode 100644 index 000000000000..a40d31c4ae1b --- /dev/null +++ b/tools/testing/selftests/bpf/progs/test_reserve_tcp_hdr_options.c @@ -0,0 +1,71 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2024 ByteDance Inc. */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#define BPF_PROG_TEST_TCP_HDR_OPTIONS +#include "test_tcp_hdr_options.h" + +unsigned int nr_err_reserve = 0; +unsigned int nr_nospc = 0; + +static bool skops_current_mss(const struct bpf_sock_ops *skops) +{ + return skops->args[0] == BPF_WRITE_HDR_TCP_CURRENT_MSS; +} + +static int handle_hdr_opt_len(struct bpf_sock_ops *skops) +{ + int err; + + if (skops_current_mss(skops)) { + err = bpf_reserve_hdr_opt(skops, 4, 0); + if (err) { + nr_err_reserve++; + RET_CG_ERR(err); + } + } else { + err = bpf_reserve_hdr_opt(skops, 8, 0); + if (err) { + if (err == -ENOSPC) { + nr_nospc++; + } else { + nr_err_reserve++; + RET_CG_ERR(err); + } + } + } + + return CG_OK; +} + +SEC("sockops") +int reserve_tcp_hdr_options(struct bpf_sock_ops *skops) +{ + switch (skops->op) { + case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: + case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB: + bpf_sock_ops_cb_flags_set(skops, + skops->bpf_sock_ops_cb_flags | + BPF_SOCK_OPS_WRITE_HDR_OPT_CB_FLAG); + break; + case BPF_SOCK_OPS_HDR_OPT_LEN_CB: + return handle_hdr_opt_len(skops); + case BPF_SOCK_OPS_WRITE_HDR_OPT_CB: + break; + } + + return CG_OK; +} + +char _license[] SEC("license") = "GPL";