[PATCH v4 bpf-next 11/11] bpf: Test BPF_SK_REUSEPORT_SELECT_OR_MIGRATE.
From: Kuniyuki Iwashima
Date: Mon Apr 26 2021 - 23:49:55 EST
This patch adds a test for BPF_SK_REUSEPORT_SELECT_OR_MIGRATE and
removes 'static' from settimeo() in network_helpers.c.
Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxxxx>
---
tools/testing/selftests/bpf/network_helpers.c | 2 +-
tools/testing/selftests/bpf/network_helpers.h | 1 +
.../bpf/prog_tests/migrate_reuseport.c | 484 ++++++++++++++++++
.../bpf/progs/test_migrate_reuseport.c | 51 ++
4 files changed, 537 insertions(+), 1 deletion(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/migrate_reuseport.c
create mode 100644 tools/testing/selftests/bpf/progs/test_migrate_reuseport.c
diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c
index 12ee40284da0..2060bc122c53 100644
--- a/tools/testing/selftests/bpf/network_helpers.c
+++ b/tools/testing/selftests/bpf/network_helpers.c
@@ -40,7 +40,7 @@ struct ipv6_packet pkt_v6 = {
.tcp.doff = 5,
};
-static int settimeo(int fd, int timeout_ms)
+int settimeo(int fd, int timeout_ms)
{
struct timeval timeout = { .tv_sec = 3 };
diff --git a/tools/testing/selftests/bpf/network_helpers.h b/tools/testing/selftests/bpf/network_helpers.h
index 7205f8afdba1..5e0d51c07b63 100644
--- a/tools/testing/selftests/bpf/network_helpers.h
+++ b/tools/testing/selftests/bpf/network_helpers.h
@@ -33,6 +33,7 @@ struct ipv6_packet {
} __packed;
extern struct ipv6_packet pkt_v6;
+int settimeo(int fd, int timeout_ms);
int start_server(int family, int type, const char *addr, __u16 port,
int timeout_ms);
int connect_to_fd(int server_fd, int timeout_ms);
diff --git a/tools/testing/selftests/bpf/prog_tests/migrate_reuseport.c b/tools/testing/selftests/bpf/prog_tests/migrate_reuseport.c
new file mode 100644
index 000000000000..1b33df1902fe
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/migrate_reuseport.c
@@ -0,0 +1,484 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Check if we can migrate child sockets.
+ *
+ * 1. call listen() for 5 server sockets.
+ * 2. update a map to migrate all child sockets
+ * to the last server socket (migrate_map[cookie] = 4)
+ * 3. call connect() for 25 client sockets.
+ * 4. call shutdown() for first 4 server sockets
+ * and migrate the requests in the accept queue
+ * to the last server socket.
+ * 5. call listen() for the second server socket.
+ * 6. call shutdown() for the last server
+ * and migrate the requests in the accept queue
+ * to the second server socket.
+ * 7. call listen() for the last server.
+ * 8. call shutdown() for the second server
+ * and migrate the requests in the accept queue
+ * to the last server socket.
+ * 9. call accept() for the last server socket.
+ *
+ * Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxxxx>
+ */
+
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+#include "test_progs.h"
+#include "test_migrate_reuseport.skel.h"
+#include "network_helpers.h"
+
+#define NR_SERVERS 5
+#define NR_CLIENTS (NR_SERVERS * 5)
+#define MIGRATED_TO (NR_SERVERS - 1)
+
+/* fastopenq->max_qlen and sk->sk_max_ack_backlog */
+#define QLEN (NR_CLIENTS * 5)
+
+#define MSG "Hello World\0"
+#define MSGLEN 12
+
+static struct migrate_reuseport_test_case {
+ const char *name;
+ __s64 servers[NR_SERVERS];
+ __s64 clients[NR_CLIENTS];
+ struct sockaddr_storage addr;
+ socklen_t addrlen;
+ int family;
+ bool drop_ack;
+ bool expire_synack_timer;
+ bool fastopen;
+} test_cases[] = {
+ {
+ .name = "IPv4 - TCP_ESTABLISHED - inet_csk_listen_stop",
+ .family = AF_INET,
+ .drop_ack = false,
+ .expire_synack_timer = false,
+ .fastopen = false,
+ },
+ {
+ .name = "IPv4 - TCP_SYN_RECV - inet_csk_listen_stop",
+ .family = AF_INET,
+ .drop_ack = true,
+ .expire_synack_timer = false,
+ .fastopen = true,
+ },
+ {
+ .name = "IPv4 - TCP_NEW_SYN_RECV - inet_csk_complete_hashdance",
+ .family = AF_INET,
+ .drop_ack = true,
+ .expire_synack_timer = false,
+ .fastopen = false,
+ },
+ {
+ .name = "IPv4 - TCP_NEW_SYN_RECV - reqsk_timer_handler",
+ .family = AF_INET,
+ .drop_ack = true,
+ .expire_synack_timer = true,
+ .fastopen = false,
+ },
+ {
+ .name = "IPv6 - TCP_ESTABLISHED - inet_csk_listen_stop",
+ .family = AF_INET6,
+ .drop_ack = false,
+ .expire_synack_timer = false,
+ .fastopen = false,
+ },
+ {
+ .name = "IPv6 - TCP_SYN_RECV - inet_csk_listen_stop",
+ .family = AF_INET6,
+ .drop_ack = true,
+ .expire_synack_timer = false,
+ .fastopen = true,
+ },
+ {
+ .name = "IPv6 - TCP_NEW_SYN_RECV - inet_csk_complete_hashdance",
+ .family = AF_INET6,
+ .drop_ack = true,
+ .expire_synack_timer = false,
+ .fastopen = false,
+ },
+ {
+ .name = "IPv6 - TCP_NEW_SYN_RECV - reqsk_timer_handler",
+ .family = AF_INET6,
+ .drop_ack = true,
+ .expire_synack_timer = true,
+ .fastopen = false,
+ }
+};
+
+static void init_fds(__s64 fds[], int len)
+{
+ int i;
+
+ for (i = 0; i < len; i++)
+ fds[i] = -1;
+}
+
+static void close_fds(__s64 fds[], int len)
+{
+ int i;
+
+ for (i = 0; i < len; i++) {
+ if (fds[i] != -1) {
+ close(fds[i]);
+ fds[i] = -1;
+ }
+ }
+}
+
+static int setup_fastopen(char *buf, int size, int *saved_len, bool restore)
+{
+ int err = 0, fd, len;
+
+ fd = open("/proc/sys/net/ipv4/tcp_fastopen", O_RDWR);
+ if (!ASSERT_NEQ(fd, -1, "open"))
+ return -1;
+
+ if (restore) {
+ len = write(fd, buf, *saved_len);
+ if (!ASSERT_EQ(len, *saved_len, "write - restore"))
+ err = -1;
+ } else {
+ *saved_len = read(fd, buf, size);
+ if (!ASSERT_LT(1, *saved_len, "read")) {
+ err = -1;
+ goto close;
+ }
+
+ err = lseek(fd, 0, SEEK_SET);
+ if (!ASSERT_OK(err, "lseek"))
+ goto close;
+
+ /* (TFO_CLIENT_ENABLE | TFO_SERVER_ENABLE) */
+ len = write(fd, "3", 1);
+ if (!ASSERT_EQ(len, 1, "write - setup"))
+ err = -1;
+ }
+
+close:
+ close(fd);
+
+ return err;
+}
+
+static int run_iptables(struct migrate_reuseport_test_case *test_case,
+ bool add_rule)
+{
+ char buf[128];
+ int err;
+
+ sprintf(buf, "%s -%c OUTPUT -o lo -p tcp --dport %d --tcp-flags SYN,ACK ACK -j DROP",
+ test_case->family == AF_INET ? "iptables" : "ip6tables",
+ add_rule ? 'A' : 'D',
+ ntohs(test_case->family == AF_INET ?
+ ((struct sockaddr_in *)&test_case->addr)->sin_port :
+ ((struct sockaddr_in6 *)&test_case->addr)->sin6_port));
+
+ err = system(buf);
+
+ return err == -1 ? err : WEXITSTATUS(err);
+}
+
+static int start_servers(struct migrate_reuseport_test_case *test_case,
+ struct test_migrate_reuseport *skel)
+{
+ int reuseport = 1, qlen = QLEN, migrated_to = MIGRATED_TO;
+ int i, err, prog_fd, reuseport_map_fd, migrate_map_fd;
+ __u64 value;
+
+ prog_fd = bpf_program__fd(skel->progs.prog_migrate_reuseport);
+ reuseport_map_fd = bpf_map__fd(skel->maps.reuseport_map);
+ migrate_map_fd = bpf_map__fd(skel->maps.migrate_map);
+
+ make_sockaddr(test_case->family,
+ test_case->family == AF_INET ? "127.0.0.1" : "::1", 0,
+ &test_case->addr, &test_case->addrlen);
+
+ for (i = 0; i < NR_SERVERS; i++) {
+ test_case->servers[i] = socket(test_case->family, SOCK_STREAM,
+ IPPROTO_TCP);
+ if (!ASSERT_NEQ(test_case->servers[i], -1, "socket"))
+ return -1;
+
+ err = setsockopt(test_case->servers[i], SOL_SOCKET,
+ SO_REUSEPORT, &reuseport, sizeof(reuseport));
+ if (!ASSERT_OK(err, "setsockopt - SO_REUSEPORT"))
+ return -1;
+
+ err = bind(test_case->servers[i],
+ (struct sockaddr *)&test_case->addr,
+ test_case->addrlen);
+ if (!ASSERT_OK(err, "bind"))
+ return -1;
+
+ if (i == 0) {
+ err = setsockopt(test_case->servers[i], SOL_SOCKET,
+ SO_ATTACH_REUSEPORT_EBPF,
+ &prog_fd, sizeof(prog_fd));
+ if (!ASSERT_OK(err,
+ "setsockopt - SO_ATTACH_REUSEPORT_EBPF"))
+ return -1;
+
+ err = getsockname(test_case->servers[i],
+ (struct sockaddr *)&test_case->addr,
+ &test_case->addrlen);
+ if (!ASSERT_OK(err, "getsockname"))
+ return -1;
+ }
+
+ if (test_case->fastopen) {
+ err = setsockopt(test_case->servers[i],
+ SOL_TCP, TCP_FASTOPEN,
+ &qlen, sizeof(qlen));
+ if (!ASSERT_OK(err, "setsockopt - TCP_FASTOPEN"))
+ return -1;
+ }
+
+ err = listen(test_case->servers[i], qlen);
+ if (!ASSERT_OK(err, "listen"))
+ return -1;
+
+ value = (__u64)test_case->servers[i];
+ err = bpf_map_update_elem(reuseport_map_fd, &i, &value,
+ BPF_NOEXIST);
+ if (!ASSERT_OK(err, "bpf_map_update_elem - reuseport_map"))
+ return -1;
+
+ err = bpf_map_lookup_elem(reuseport_map_fd, &i, &value);
+ if (!ASSERT_OK(err, "bpf_map_lookup_elem - reuseport_map"))
+ return -1;
+
+ err = bpf_map_update_elem(migrate_map_fd, &value, &migrated_to,
+ BPF_NOEXIST);
+ if (!ASSERT_OK(err, "bpf_map_update_elem - migrate_map"))
+ return -1;
+ }
+
+ return 0;
+}
+
+static int start_clients(struct migrate_reuseport_test_case *test_case)
+{
+ char buf[MSGLEN] = MSG;
+ int i, err;
+
+ for (i = 0; i < NR_CLIENTS; i++) {
+ test_case->clients[i] = socket(test_case->family, SOCK_STREAM,
+ IPPROTO_TCP);
+ if (!ASSERT_NEQ(test_case->clients[i], -1, "socket"))
+ return -1;
+
+ /* iptables only drops the final ACK, so clients will
+ * transition to TCP_ESTABLISHED immediately.
+ */
+ err = settimeo(test_case->clients[i], 100);
+ if (!ASSERT_OK(err, "settimeo"))
+ return -1;
+
+ if (test_case->fastopen) {
+ int fastopen = 1;
+
+ err = setsockopt(test_case->clients[i], IPPROTO_TCP,
+ TCP_FASTOPEN_CONNECT, &fastopen,
+ sizeof(fastopen));
+ if (!ASSERT_OK(err,
+ "setsockopt - TCP_FASTOPEN_CONNECT"))
+ return -1;
+ }
+
+ err = connect(test_case->clients[i],
+ (struct sockaddr *)&test_case->addr,
+ test_case->addrlen);
+ if (!ASSERT_OK(err, "connect"))
+ return -1;
+
+ err = write(test_case->clients[i], buf, MSGLEN);
+ if (!ASSERT_EQ(err, MSGLEN, "write"))
+ return -1;
+ }
+
+ return 0;
+}
+
+static int migrate_dance(struct migrate_reuseport_test_case *test_case)
+{
+ int i, err;
+
+ /* Migrate TCP_ESTABLISHED and TCP_SYN_RECV requests
+ * to the last listener based on eBPF.
+ */
+ for (i = 0; i < MIGRATED_TO; i++) {
+ err = shutdown(test_case->servers[i], SHUT_RDWR);
+ if (!ASSERT_OK(err, "shutdown"))
+ return -1;
+ }
+
+ /* No dance for TCP_NEW_SYN_RECV to migrate based on eBPF */
+ if (!test_case->fastopen && test_case->drop_ack)
+ return 0;
+
+ /* Note that we use the second listener instead of the
+ * first one here.
+ *
+ * The fist listener is bind()ed with port 0 and,
+ * SOCK_BINDPORT_LOCK is not set to sk_userlocks, so
+ * calling listen() again will bind() the first listener
+ * on a new ephemeral port and detach it from the existing
+ * reuseport group. (See: __inet_bind(), tcp_set_state())
+ *
+ * OTOH, the second one is bind()ed with a specific port,
+ * and SOCK_BINDPORT_LOCK is set. Thus, re-listen() will
+ * resurrect the listener on the existing reuseport group.
+ */
+ err = listen(test_case->servers[1], QLEN);
+ if (!ASSERT_OK(err, "listen"))
+ return -1;
+
+ /* Migrate from the last listener to the second one.
+ *
+ * All listeners were detached out of the reuseport_map,
+ * so migration will be done by kernel random pick from here.
+ */
+ err = shutdown(test_case->servers[MIGRATED_TO], SHUT_RDWR);
+ if (!ASSERT_OK(err, "shutdown"))
+ return -1;
+
+ /* Back to the existing reuseport group */
+ err = listen(test_case->servers[MIGRATED_TO], QLEN);
+ if (!ASSERT_OK(err, "listen"))
+ return -1;
+
+ /* Migrate back to the last one from the second one */
+ err = shutdown(test_case->servers[1], SHUT_RDWR);
+ if (!ASSERT_OK(err, "shutdown"))
+ return -1;
+
+ return 0;
+}
+
+static int count_requests(struct migrate_reuseport_test_case *test_case)
+{
+ struct sockaddr_storage addr;
+ socklen_t len = sizeof(addr);
+ char buf[MSGLEN];
+ int cnt, client;
+
+ settimeo(test_case->servers[MIGRATED_TO], 2000);
+
+ for (cnt = 0; cnt < NR_CLIENTS; cnt++) {
+ client = accept(test_case->servers[MIGRATED_TO],
+ (struct sockaddr *)&addr, &len);
+ if (!ASSERT_NEQ(client, -1, "accept"))
+ goto out;
+
+ memset(buf, 0, MSGLEN);
+
+ read(client, &buf, MSGLEN);
+ if (!ASSERT_STREQ(buf, MSG, "read")) {
+ close(client);
+ goto out;
+ }
+
+ close(client);
+ }
+
+out:
+ return cnt;
+}
+
+static void run_test(struct migrate_reuseport_test_case *test_case,
+ struct test_migrate_reuseport *skel)
+{
+ bool added_rule = false;
+ int err, saved_len;
+ char buf[16];
+
+ init_fds(test_case->servers, NR_SERVERS);
+ init_fds(test_case->clients, NR_CLIENTS);
+
+ if (test_case->fastopen) {
+ memset(buf, 0, sizeof(buf));
+
+ err = setup_fastopen(buf, sizeof(buf), &saved_len, false);
+ if (!ASSERT_OK(err, "setup_fastopen - setup"))
+ return;
+ }
+
+ err = start_servers(test_case, skel);
+ if (!ASSERT_OK(err, "start_servers"))
+ goto close_servers;
+
+ if (test_case->drop_ack) {
+ /* Drop the final ACK of the 3-way handshake and stick the
+ * in-flight requests on TCP_SYN_RECV or TCP_NEW_SYN_RECV.
+ */
+ err = run_iptables(test_case, true);
+ if (!ASSERT_OK(err, "run_iptables - add rule"))
+ goto close_servers;
+
+ added_rule = true;
+ }
+
+ err = start_clients(test_case);
+ if (!ASSERT_OK(err, "start_clients"))
+ goto close_clients;
+
+ /* Migrate the requests in the accept queue only.
+ * TCP_NEW_SYN_RECV requests are not migrated at this point.
+ */
+ err = migrate_dance(test_case);
+ if (!ASSERT_OK(err, "migrate_dance"))
+ goto close_clients;
+
+ if (test_case->expire_synack_timer) {
+ /* Wait for SYN+ACK timer to expire so that
+ * reqsk_timer_handler() migrates TCP_NEW_SYN_RECV requests.
+ */
+ sleep(1);
+ }
+
+ if (test_case->drop_ack) {
+ /* Resume 3WHS and migrate TCP_NEW_SYN_RECV requests */
+ err = run_iptables(test_case, false);
+ if (!ASSERT_OK(err, "run_iptables - delete rule"))
+ goto close_clients;
+
+ added_rule = false;
+ }
+
+ err = count_requests(test_case);
+ ASSERT_EQ(err, NR_CLIENTS, test_case->name);
+
+close_clients:
+ close_fds(test_case->clients, NR_CLIENTS);
+
+ if (added_rule) {
+ err = run_iptables(test_case, false);
+ ASSERT_OK(err, "run_iptables - clean up rule");
+ }
+
+close_servers:
+ close_fds(test_case->servers, NR_SERVERS);
+
+ if (test_case->fastopen) {
+ err = setup_fastopen(buf, sizeof(buf), &saved_len, true);
+ ASSERT_OK(err, "setup_fastopen - restore");
+ }
+}
+
+void test_migrate_reuseport(void)
+{
+ struct test_migrate_reuseport *skel;
+ int i;
+
+ skel = test_migrate_reuseport__open_and_load();
+ if (!ASSERT_OK_PTR(skel, "open_and_load"))
+ return;
+
+ for (i = 0; i < ARRAY_SIZE(test_cases); i++)
+ run_test(&test_cases[i], skel);
+
+ test_migrate_reuseport__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_migrate_reuseport.c b/tools/testing/selftests/bpf/progs/test_migrate_reuseport.c
new file mode 100644
index 000000000000..d7136dc29fa2
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_migrate_reuseport.c
@@ -0,0 +1,51 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Check if we can migrate child sockets.
+ *
+ * 1. If reuse_md->migrating_sk is NULL (SYN packet),
+ * return SK_PASS without selecting a listener.
+ * 2. If reuse_md->migrating_sk is not NULL (socket migration),
+ * select a listener (reuseport_map[migrate_map[cookie]])
+ *
+ * Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxxxx>
+ */
+
+#include <stddef.h>
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+struct {
+ __uint(type, BPF_MAP_TYPE_REUSEPORT_SOCKARRAY);
+ __uint(max_entries, 256);
+ __type(key, int);
+ __type(value, __u64);
+} reuseport_map SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_HASH);
+ __uint(max_entries, 256);
+ __type(key, __u64);
+ __type(value, int);
+} migrate_map SEC(".maps");
+
+SEC("sk_reuseport/migrate")
+int prog_migrate_reuseport(struct sk_reuseport_md *reuse_md)
+{
+ int *key, flags = 0;
+ __u64 cookie;
+
+ if (!reuse_md->migrating_sk)
+ return SK_PASS;
+
+ cookie = bpf_get_socket_cookie(reuse_md->sk);
+
+ key = bpf_map_lookup_elem(&migrate_map, &cookie);
+ if (!key)
+ return SK_DROP;
+
+ bpf_sk_select_reuseport(reuse_md, &reuseport_map, key, flags);
+
+ return SK_PASS;
+}
+
+char _license[] SEC("license") = "GPL";
--
2.30.2