From f2a6ee924d26527dc55a745dc917a820f34e64e5 Mon Sep 17 00:00:00 2001 From: Prankur Gupta Date: Tue, 17 Aug 2021 15:42:21 -0700 Subject: [PATCH] selftests/bpf: Add tests for {set|get} socket option from setsockopt BPF Adding selftests for the newly added functionality to call bpf_setsockopt() and bpf_getsockopt() from setsockopt BPF programs. Test Details: 1. BPF Program Checks for changes in IPV6_TCLASS(SOL_IPV6) via setsockopt If the cca for the socket is not cubic do nothing If the newly set value for IPV6_TCLASS is 45 (0x2d) (as per our use-case) then change the cc from cubic to reno 2. User Space Program Creates an AF_INET6 socket and set the cca for that to be "cubic" Attach the program and set the IPV6_TCLASS to 0x2d using setsockopt Verify the cca for the socket changed to reno Signed-off-by: Prankur Gupta Signed-off-by: Daniel Borkmann Acked-by: Song Liu Link: https://lore.kernel.org/bpf/20210817224221.3257826-3-prankgup@fb.com --- tools/testing/selftests/bpf/bpf_tcp_helpers.h | 18 ++++++ .../selftests/bpf/prog_tests/sockopt_qos_to_cc.c | 70 ++++++++++++++++++++++ .../selftests/bpf/progs/sockopt_qos_to_cc.c | 39 ++++++++++++ 3 files changed, 127 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/sockopt_qos_to_cc.c create mode 100644 tools/testing/selftests/bpf/progs/sockopt_qos_to_cc.c diff --git a/tools/testing/selftests/bpf/bpf_tcp_helpers.h b/tools/testing/selftests/bpf/bpf_tcp_helpers.h index 029589c..c9f9bda 100644 --- a/tools/testing/selftests/bpf/bpf_tcp_helpers.h +++ b/tools/testing/selftests/bpf/bpf_tcp_helpers.h @@ -12,6 +12,10 @@ SEC("struct_ops/"#name) \ BPF_PROG(name, args) +#ifndef SOL_TCP +#define SOL_TCP 6 +#endif + #define tcp_jiffies32 ((__u32)bpf_jiffies64()) struct sock_common { @@ -203,6 +207,20 @@ static __always_inline bool tcp_is_cwnd_limited(const struct sock *sk) return !!BPF_CORE_READ_BITFIELD(tp, is_cwnd_limited); } +static __always_inline bool tcp_cc_eq(const char *a, const char *b) +{ + int i; + + for (i = 0; i < TCP_CA_NAME_MAX; i++) { + if (a[i] != b[i]) + return false; + if (!a[i]) + break; + } + + return true; +} + extern __u32 tcp_slow_start(struct tcp_sock *tp, __u32 acked) __ksym; extern void tcp_cong_avoid_ai(struct tcp_sock *tp, __u32 w, __u32 acked) __ksym; diff --git a/tools/testing/selftests/bpf/prog_tests/sockopt_qos_to_cc.c b/tools/testing/selftests/bpf/prog_tests/sockopt_qos_to_cc.c new file mode 100644 index 0000000..6b53b3c --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/sockopt_qos_to_cc.c @@ -0,0 +1,70 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ +#include +#include +#include "sockopt_qos_to_cc.skel.h" + +static void run_setsockopt_test(int cg_fd, int sock_fd) +{ + socklen_t optlen; + char cc[16]; /* TCP_CA_NAME_MAX */ + int buf; + int err = -1; + + buf = 0x2D; + err = setsockopt(sock_fd, SOL_IPV6, IPV6_TCLASS, &buf, sizeof(buf)); + if (!ASSERT_OK(err, "setsockopt(sock_fd, IPV6_TCLASS)")) + return; + + /* Verify the setsockopt cc change */ + optlen = sizeof(cc); + err = getsockopt(sock_fd, SOL_TCP, TCP_CONGESTION, cc, &optlen); + if (!ASSERT_OK(err, "getsockopt(sock_fd, TCP_CONGESTION)")) + return; + + if (!ASSERT_STREQ(cc, "reno", "getsockopt(sock_fd, TCP_CONGESTION)")) + return; +} + +void test_sockopt_qos_to_cc(void) +{ + struct sockopt_qos_to_cc *skel; + char cc_cubic[16] = "cubic"; /* TCP_CA_NAME_MAX */ + int cg_fd = -1; + int sock_fd = -1; + int err; + + cg_fd = test__join_cgroup("/sockopt_qos_to_cc"); + if (!ASSERT_GE(cg_fd, 0, "cg-join(sockopt_qos_to_cc)")) + return; + + skel = sockopt_qos_to_cc__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel")) + goto done; + + sock_fd = socket(AF_INET6, SOCK_STREAM, 0); + if (!ASSERT_GE(sock_fd, 0, "v6 socket open")) + goto done; + + err = setsockopt(sock_fd, SOL_TCP, TCP_CONGESTION, &cc_cubic, + sizeof(cc_cubic)); + if (!ASSERT_OK(err, "setsockopt(sock_fd, TCP_CONGESTION)")) + goto done; + + skel->links.sockopt_qos_to_cc = + bpf_program__attach_cgroup(skel->progs.sockopt_qos_to_cc, + cg_fd); + if (!ASSERT_OK_PTR(skel->links.sockopt_qos_to_cc, + "prog_attach(sockopt_qos_to_cc)")) + goto done; + + run_setsockopt_test(cg_fd, sock_fd); + +done: + if (sock_fd != -1) + close(sock_fd); + if (cg_fd != -1) + close(cg_fd); + /* destroy can take null and error pointer */ + sockopt_qos_to_cc__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/sockopt_qos_to_cc.c b/tools/testing/selftests/bpf/progs/sockopt_qos_to_cc.c new file mode 100644 index 0000000..1bce83b --- /dev/null +++ b/tools/testing/selftests/bpf/progs/sockopt_qos_to_cc.c @@ -0,0 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ +#include +#include +#include +#include +#include +#include "bpf_tcp_helpers.h" + +char _license[] SEC("license") = "GPL"; + +SEC("cgroup/setsockopt") +int sockopt_qos_to_cc(struct bpf_sockopt *ctx) +{ + void *optval_end = ctx->optval_end; + int *optval = ctx->optval; + char buf[TCP_CA_NAME_MAX]; + char cc_reno[TCP_CA_NAME_MAX] = "reno"; + char cc_cubic[TCP_CA_NAME_MAX] = "cubic"; + + if (ctx->level != SOL_IPV6 || ctx->optname != IPV6_TCLASS) + return 1; + + if (optval + 1 > optval_end) + return 0; /* EPERM, bounds check */ + + if (bpf_getsockopt(ctx->sk, SOL_TCP, TCP_CONGESTION, &buf, sizeof(buf))) + return 0; + + if (!tcp_cc_eq(buf, cc_cubic)) + return 0; + + if (*optval == 0x2d) { + if (bpf_setsockopt(ctx->sk, SOL_TCP, TCP_CONGESTION, &cc_reno, + sizeof(cc_reno))) + return 0; + } + return 1; +} -- 2.7.4