This test creates a client and a server exchanging a single byte with a Segment Routing Header and the eBPF program saves the inner segment in a sk_storage. The test program checks that the segment is correct.

Signed-off-by: Mathieu Jadin mathjadin@gmail.com --- .../bpf/prog_tests/tcp_ipv6_exthdr_srh.c | 171 ++++++++++++++++++ .../selftests/bpf/progs/tcp_ipv6_exthdr_srh.c | 78 ++++++++ 2 files changed, 249 insertions(+) create mode 100644 tools/testing/selftests/bpf/prog_tests/tcp_ipv6_exthdr_srh.c create mode 100644 tools/testing/selftests/bpf/progs/tcp_ipv6_exthdr_srh.c

diff --git a/tools/testing/selftests/bpf/prog_tests/tcp_ipv6_exthdr_srh.c b/tools/testing/selftests/bpf/prog_tests/tcp_ipv6_exthdr_srh.c new file mode 100644 index 000000000000..70f7ee230975 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/tcp_ipv6_exthdr_srh.c @@ -0,0 +1,171 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <test_progs.h> +#include <linux/seg6.h> +#include "cgroup_helpers.h" +#include "network_helpers.h" + +struct tcp_srh_storage { + struct in6_addr inner_segment; +}; + +static void send_byte(int fd) +{ + char b = 0x55; + + if (CHECK_FAIL(send(fd, &b, sizeof(b), 0) != 1)) + perror("Failed to send single byte"); +} + +static int verify_srh(int map_fd, int server_fd, struct ipv6_sr_hdr *client_srh) +{ + int err = 0; + struct tcp_srh_storage val; + + if (CHECK_FAIL(bpf_map_lookup_elem(map_fd, &server_fd, &val) < 0)) { + perror("Failed to read socket storage"); + return -1; + } + + if (memcmp(&val.inner_segment, &client_srh->segments[1], + sizeof(struct in6_addr))) { + log_err("The inner segment of the received SRH differs from the sent one"); + err++; + } + + return err; +} + +static int run_test(int cgroup_fd, int listen_fd) +{ + struct bpf_prog_load_attr attr = { + .prog_type = BPF_PROG_TYPE_SOCK_OPS, + .file = "./tcp_ipv6_exthdr_srh.o", + .expected_attach_type = BPF_CGROUP_SOCK_OPS, + }; + size_t srh_size = sizeof(struct ipv6_sr_hdr) + + 2 * sizeof(struct in6_addr); + struct ipv6_sr_hdr *client_srh; + struct bpf_object *obj; + struct bpf_map *map; + struct timeval tv; + int client_fd; + int server_fd; + int prog_fd; + int map_fd; + char byte; + int err; + + err = bpf_prog_load_xattr(&attr, &obj, &prog_fd); + if (err) { + log_err("Failed to load BPF object"); + return -1; + } + + map = bpf_object__next_map(obj, NULL); + 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 = connect_to_fd(listen_fd, 0); + if (client_fd < 0) { + err = -1; + goto close_bpf_object; + } + + server_fd = accept(listen_fd, NULL, 0); + if (server_fd < 0) { + err = -1; + goto close_client_fd; + } + + /* Set an SRH with ::1 as an intermediate segment on the client */ + + client_srh = calloc(1, srh_size); + if (!client_srh) { + log_err("Failed to create the SRH to send"); + goto close_server_fd; + } + client_srh->type = IPV6_SRCRT_TYPE_4; + // We do not count the first 8 bytes (RFC 8200 Section 4.4) + client_srh->hdrlen = (2 * sizeof(struct in6_addr)) >> 3; + client_srh->segments_left = 1; + client_srh->first_segment = 1; + // client_srh->segments[0] is set by the kernel + memcpy(&client_srh->segments[1], &in6addr_loopback, + sizeof(struct in6_addr)); + + if (setsockopt(client_fd, SOL_IPV6, IPV6_RTHDR, client_srh, + srh_size)) { + log_err("Failed to set the SRH on the client"); + goto free_srh; + } + + /* Send traffic with this SRH + * and check its parsing on the server side + */ + + tv.tv_sec = 1; + tv.tv_usec = 0; + if (setsockopt(server_fd, SOL_SOCKET, SO_RCVTIMEO, (const char *)&tv, + sizeof(tv))) { + log_err("Failed to set the receive timeout on the server"); + err = -1; + goto free_srh; + } + + send_byte(client_fd); + if (recv(server_fd, &byte, 1, 0) != 1) { + log_err("Failed to get the byte under one second on the server 2"); + err = -1; + goto free_srh; + } + + err += verify_srh(map_fd, server_fd, client_srh); + +free_srh: + free(client_srh); +close_server_fd: + close(server_fd); +close_client_fd: + close(client_fd); +close_bpf_object: + bpf_object__close(obj); + return err; +} + +void test_tcp_ipv6_exthdr_srh(void) +{ + int server_fd, cgroup_fd; + + cgroup_fd = test__join_cgroup("/tcp_ipv6_exthdr_srh"); + if (CHECK_FAIL(cgroup_fd < 0)) + return; + + server_fd = start_server(AF_INET6, SOCK_STREAM, "::1", 0, 0); + if (CHECK_FAIL(server_fd < 0)) + goto close_cgroup_fd; + + if (CHECK_FAIL(system("sysctl net.ipv6.conf.all.seg6_enabled=1"))) + goto close_server; + + if (CHECK_FAIL(system("sysctl net.ipv6.conf.lo.seg6_enabled=1"))) + goto reset_sysctl; + + CHECK_FAIL(run_test(cgroup_fd, server_fd)); + + if (CHECK_FAIL(system("sysctl net.ipv6.conf.lo.seg6_enabled=0"))) + log_err("Cannot reset sysctl net.ipv6.conf.lo.seg6_enabled to 0"); + +reset_sysctl: + if (CHECK_FAIL(system("sysctl net.ipv6.conf.all.seg6_enabled=0"))) + log_err("Cannot reset sysctl net.ipv6.conf.all.seg6_enabled to 0"); + +close_server: + close(server_fd); +close_cgroup_fd: + close(cgroup_fd); +} diff --git a/tools/testing/selftests/bpf/progs/tcp_ipv6_exthdr_srh.c b/tools/testing/selftests/bpf/progs/tcp_ipv6_exthdr_srh.c new file mode 100644 index 000000000000..cb4b4e23e337 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/tcp_ipv6_exthdr_srh.c @@ -0,0 +1,78 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/types.h> +#include <bpf/bpf_helpers.h> +#include <linux/in6.h> +#include <linux/ipv6.h> +#include <linux/seg6.h> +#include <linux/bpf.h> + +char _license[] SEC("license") = "GPL"; + +#define NEXTHDR_ROUTING 43 + +struct tcp_srh_storage { + struct in6_addr inner_segment; +}; + +struct { + __uint(type, BPF_MAP_TYPE_SK_STORAGE); + __uint(map_flags, BPF_F_NO_PREALLOC); + __type(key, int); + __type(value, struct tcp_srh_storage); +} socket_storage_map SEC(".maps"); + +/* Check the header received from the active side */ +static int read_incoming_srh(struct bpf_sock_ops *skops, + struct tcp_srh_storage *storage) +{ + __u32 seg_size = 2 * sizeof(struct in6_addr); + struct ipv6_sr_hdr *srh; + struct ipv6hdr *ip6; + void *seg_list; + int ret = 1; + + ip6 = (struct ipv6hdr *)skops->skb_data; + if (ip6 + 1 <= skops->skb_data_end && ip6->nexthdr == NEXTHDR_ROUTING) { + srh = (struct ipv6_sr_hdr *)(ip6 + 1); + if (srh + 1 <= skops->skb_data_end) { + if (srh->type != IPV6_SRCRT_TYPE_4) + return ret; + + seg_list = (void *)(srh + 1); + if (seg_list + seg_size <= skops->skb_data_end) { + // This is an SRH with at least 2 segments + storage->inner_segment = srh->segments[1]; + ret = 0; + } + } + } + + return ret; +} + +SEC("sockops") +int srh_read(struct bpf_sock_ops *skops) +{ + struct tcp_srh_storage *storage; + int true_val = 1; + + if (!skops->sk) + return 1; + + storage = bpf_sk_storage_get(&socket_storage_map, skops->sk, 0, + BPF_SK_STORAGE_GET_F_CREATE); + if (!storage) + return 1; + + switch (skops->op) { + case BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB: + case BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB: + bpf_sock_ops_cb_flags_set(skops, skops->bpf_sock_ops_cb_flags | + BPF_SOCK_OPS_PARSE_IPV6_HDR_CB_FLAG); + break; + case BPF_SOCK_OPS_PARSE_IPV6_HDR_CB: + return read_incoming_srh(skops, storage); + } + + return 0; +}