This patch adds a base for MPTCP specific tests.

It is currently limited to the is_mptcp field in case of plain TCP connection because for the moment there is no easy way to get the subflow sk from a msk in userspace. This implies that we cannot lookup the sk_storage attached to the subflow sk in the sockops program.

Acked-by: Matthieu Baerts matthieu.baerts@tessares.net Signed-off-by: Nicolas Rybowski nicolas.rybowski@tessares.net ---

Notes: v1 -> v2: - new patch: mandatory selftests (Alexei)

tools/testing/selftests/bpf/config | 1 + tools/testing/selftests/bpf/network_helpers.c | 37 +++++- tools/testing/selftests/bpf/network_helpers.h | 3 + .../testing/selftests/bpf/prog_tests/mptcp.c | 119 ++++++++++++++++++ tools/testing/selftests/bpf/progs/mptcp.c | 48 +++++++ 5 files changed, 203 insertions(+), 5 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/mptcp.c create mode 100644 tools/testing/selftests/bpf/progs/mptcp.c

diff --git a/tools/testing/selftests/bpf/config b/tools/testing/selftests/bpf/config index 2118e23ac07a..8377836ea976 100644 --- a/tools/testing/selftests/bpf/config +++ b/tools/testing/selftests/bpf/config @@ -39,3 +39,4 @@ CONFIG_BPF_JIT=y CONFIG_BPF_LSM=y CONFIG_SECURITY=y CONFIG_LIRC=y +CONFIG_MPTCP=y diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c index 12ee40284da0..85cbb683965c 100644 --- a/tools/testing/selftests/bpf/network_helpers.c +++ b/tools/testing/selftests/bpf/network_helpers.c @@ -14,6 +14,10 @@ #include "bpf_util.h" #include "network_helpers.h"

+#ifndef IPPROTO_MPTCP +#define IPPROTO_MPTCP 262 +#endif + #define clean_errno() (errno == 0 ? "None" : strerror(errno)) #define log_err(MSG, ...) ({ \ int __save = errno; \ @@ -66,8 +70,8 @@ static int settimeo(int fd, int timeout_ms)

#define save_errno_close(fd) ({ int __save = errno; close(fd); errno = __save; })

-int start_server(int family, int type, const char *addr_str, __u16 port, - int timeout_ms) +static int start_server_proto(int family, int type, int protocol, + const char *addr_str, __u16 port, int timeout_ms) { struct sockaddr_storage addr = {}; socklen_t len; @@ -76,7 +80,7 @@ int start_server(int family, int type, const char *addr_str, __u16 port, if (make_sockaddr(family, addr_str, port, &addr, &len)) return -1;

- fd = socket(family, type, 0); + fd = socket(family, type, protocol); if (fd < 0) { log_err("Failed to create server socket"); return -1; @@ -104,6 +108,19 @@ int start_server(int family, int type, const char *addr_str, __u16 port, return -1; }

+int start_server(int family, int type, const char *addr_str, __u16 port, + int timeout_ms) +{ + return start_server_proto(family, type, 0, addr_str, port, timeout_ms); +} + +int start_mptcp_server(int family, const char *addr_str, __u16 port, + int timeout_ms) +{ + return start_server_proto(family, SOCK_STREAM, IPPROTO_MPTCP, addr_str, + port, timeout_ms); +} + int fastopen_connect(int server_fd, const char *data, unsigned int data_len, int timeout_ms) { @@ -153,7 +170,7 @@ static int connect_fd_to_addr(int fd, return 0; }

-int connect_to_fd(int server_fd, int timeout_ms) +static int connect_to_fd_proto(int server_fd, int protocol, int timeout_ms) { struct sockaddr_storage addr; struct sockaddr_in *addr_in; @@ -173,7 +190,7 @@ int connect_to_fd(int server_fd, int timeout_ms) }

addr_in = (struct sockaddr_in *)&addr; - fd = socket(addr_in->sin_family, type, 0); + fd = socket(addr_in->sin_family, type, protocol); if (fd < 0) { log_err("Failed to create client socket"); return -1; @@ -192,6 +209,16 @@ int connect_to_fd(int server_fd, int timeout_ms) return -1; }

+int connect_to_fd(int server_fd, int timeout_ms) +{ + return connect_to_fd_proto(server_fd, 0, timeout_ms); +} + +int connect_to_mptcp_fd(int server_fd, int timeout_ms) +{ + return connect_to_fd_proto(server_fd, IPPROTO_MPTCP, timeout_ms); +} + int connect_fd_to_fd(int client_fd, int server_fd, int timeout_ms) { struct sockaddr_storage addr; diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h index 7205f8afdba1..336423a789e9 100644 --- a/tools/testing/selftests/bpf/network_helpers.h +++ b/tools/testing/selftests/bpf/network_helpers.h @@ -35,7 +35,10 @@ extern struct ipv6_packet pkt_v6;

int start_server(int family, int type, const char *addr, __u16 port, int timeout_ms); +int start_mptcp_server(int family, const char *addr, __u16 port, + int timeout_ms); int connect_to_fd(int server_fd, int timeout_ms); +int connect_to_mptcp_fd(int server_fd, int timeout_ms); int connect_fd_to_fd(int client_fd, int server_fd, int timeout_ms); int fastopen_connect(int server_fd, const char *data, unsigned int data_len, int timeout_ms); diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c new file mode 100644 index 000000000000..0e65d64868e9 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c @@ -0,0 +1,119 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <test_progs.h> +#include "cgroup_helpers.h" +#include "network_helpers.h" + +struct mptcp_storage { + __u32 invoked; + __u32 is_mptcp; +}; + +static int verify_sk(int map_fd, int client_fd, const char *msg, __u32 is_mptcp) +{ + int err = 0, cfd = client_fd; + struct mptcp_storage val; + + /* Currently there is no easy way to get back the subflow sk from the MPTCP + * sk, thus we cannot access here the sk_storage associated to the subflow + * sk. Also, there is no sk_storage associated with the MPTCP sk since it + * does not trigger sockops events. + * We silently pass this situation at the moment. + */ + if (is_mptcp == 1) + return 0; + + if (CHECK_FAIL(bpf_map_lookup_elem(map_fd, &cfd, &val) < 0)) { + perror("Failed to read socket storage"); + return -1; + } + + if (val.invoked != 1) { + log_err("%s: unexpected invoked count %d != %d", + msg, val.invoked, 1); + err++; + } + + if (val.is_mptcp != is_mptcp) { + log_err("%s: unexpected bpf_tcp_sock.is_mptcp %d != %d", + msg, val.is_mptcp, is_mptcp); + err++; + } + + return err; +} + +static int run_test(int cgroup_fd, int server_fd, bool is_mptcp) +{ + int client_fd, prog_fd, map_fd, err; + struct bpf_object *obj; + struct bpf_map *map; + + struct bpf_prog_load_attr attr = { + .prog_type = BPF_PROG_TYPE_SOCK_OPS, + .file = "./mptcp.o", + .expected_attach_type = BPF_CGROUP_SOCK_OPS, + }; + + err = bpf_prog_load_xattr(&attr, &obj, &prog_fd); + if (err) { + log_err("Failed to load BPF object"); + return -1; + } + + map = bpf_map__next(NULL, obj); + map_fd = bpf_map__fd(map); + + err = bpf_prog_attach(prog_fd, cgroup_fd, BPF_CGROUP_SOCK_OPS, 0); + if (err) { + log_err("Failed to attach BPF program"); + goto close_bpf_object; + } + + client_fd = is_mptcp ? connect_to_mptcp_fd(server_fd, 0) : + connect_to_fd(server_fd, 0); + if (client_fd < 0) { + err = -1; + goto close_client_fd; + } + + err += is_mptcp ? verify_sk(map_fd, client_fd, "MPTCP subflow socket", 1) : + verify_sk(map_fd, client_fd, "plain TCP socket", 0); + +close_client_fd: + close(client_fd); + +close_bpf_object: + bpf_object__close(obj); + return err; +} + +void test_mptcp(void) +{ + int server_fd, cgroup_fd; + + cgroup_fd = test__join_cgroup("/mptcp"); + if (CHECK_FAIL(cgroup_fd < 0)) + return; + + /* without MPTCP */ + server_fd = start_server(AF_INET, SOCK_STREAM, NULL, 0, 0); + if (CHECK_FAIL(server_fd < 0)) + goto with_mptcp; + + CHECK_FAIL(run_test(cgroup_fd, server_fd, false)); + + close(server_fd); + +with_mptcp: + /* with MPTCP */ + server_fd = start_mptcp_server(AF_INET, NULL, 0, 0); + if (CHECK_FAIL(server_fd < 0)) + goto close_cgroup_fd; + + CHECK_FAIL(run_test(cgroup_fd, server_fd, true)); + + close(server_fd); + +close_cgroup_fd: + close(cgroup_fd); +} diff --git a/tools/testing/selftests/bpf/progs/mptcp.c b/tools/testing/selftests/bpf/progs/mptcp.c new file mode 100644 index 000000000000..be5ee8dac2b3 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/mptcp.c @@ -0,0 +1,48 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/bpf.h> +#include <bpf/bpf_helpers.h> + +char _license[] SEC("license") = "GPL"; +__u32 _version SEC("version") = 1; + +struct mptcp_storage { + __u32 invoked; + __u32 is_mptcp; +}; + +struct { + __uint(type, BPF_MAP_TYPE_SK_STORAGE); + __uint(map_flags, BPF_F_NO_PREALLOC); + __type(key, int); + __type(value, struct mptcp_storage); +} socket_storage_map SEC(".maps"); + +SEC("sockops") +int _sockops(struct bpf_sock_ops *ctx) +{ + struct mptcp_storage *storage; + struct bpf_tcp_sock *tcp_sk; + int op = (int)ctx->op; + struct bpf_sock *sk; + + sk = ctx->sk; + if (!sk) + return 1; + + storage = bpf_sk_storage_get(&socket_storage_map, sk, 0, + BPF_SK_STORAGE_GET_F_CREATE); + if (!storage) + return 1; + + if (op != BPF_SOCK_OPS_TCP_CONNECT_CB) + return 1; + + tcp_sk = bpf_tcp_sock(sk); + if (!tcp_sk) + return 1; + + storage->invoked++; + storage->is_mptcp = tcp_sk->is_mptcp; + + return 1; +}