new file mode 100644
@@ -0,0 +1,173 @@
+// 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 socket
+ * to the last server socket (migrate_map[cookie] = 4)
+ * 3. call connect() for 25 client sockets.
+ * 4. call close() for first 4 server sockets.
+ * 5. call accept() for the last server socket.
+ *
+ * Author: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
+ */
+
+#include <bpf/bpf.h>
+#include <bpf/libbpf.h>
+
+#include "test_progs.h"
+#include "test_select_reuseport_migrate.skel.h"
+
+#define ADDRESS "127.0.0.1"
+#define PORT 80
+#define NUM_SERVERS 5
+#define NUM_CLIENTS (NUM_SERVERS * 5)
+
+
+static int test_listen(struct test_select_reuseport_migrate *skel, int server_fds[])
+{
+ int i, err, optval = 1, migrated_to = NUM_SERVERS - 1;
+ int prog_fd, reuseport_map_fd, migrate_map_fd;
+ struct sockaddr_in addr;
+ socklen_t addr_len;
+ __u64 value;
+
+ prog_fd = bpf_program__fd(skel->progs.prog_select_reuseport_migrate);
+ reuseport_map_fd = bpf_map__fd(skel->maps.reuseport_map);
+ migrate_map_fd = bpf_map__fd(skel->maps.migrate_map);
+
+ addr_len = sizeof(addr);
+ addr.sin_family = AF_INET;
+ addr.sin_port = htons(PORT);
+ inet_pton(AF_INET, ADDRESS, &addr.sin_addr.s_addr);
+
+ for (i = 0; i < NUM_SERVERS; i++) {
+ server_fds[i] = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+ if (CHECK_FAIL(server_fds[i] == -1))
+ return -1;
+
+ err = setsockopt(server_fds[i], SOL_SOCKET, SO_REUSEPORT,
+ &optval, sizeof(optval));
+ if (CHECK_FAIL(err == -1))
+ return -1;
+
+ if (i == 0) {
+ err = setsockopt(server_fds[i], SOL_SOCKET, SO_ATTACH_REUSEPORT_EBPF,
+ &prog_fd, sizeof(prog_fd));
+ if (CHECK_FAIL(err == -1))
+ return -1;
+ }
+
+ err = bind(server_fds[i], (struct sockaddr *)&addr, addr_len);
+ if (CHECK_FAIL(err == -1))
+ return -1;
+
+ err = listen(server_fds[i], 32);
+ if (CHECK_FAIL(err == -1))
+ return -1;
+
+ err = bpf_map_update_elem(reuseport_map_fd, &i, &server_fds[i], BPF_NOEXIST);
+ if (CHECK_FAIL(err == -1))
+ return -1;
+
+ err = bpf_map_lookup_elem(reuseport_map_fd, &i, &value);
+ if (CHECK_FAIL(err == -1))
+ return -1;
+
+ err = bpf_map_update_elem(migrate_map_fd, &value, &migrated_to, BPF_NOEXIST);
+ if (CHECK_FAIL(err == -1))
+ return -1;
+ }
+
+ return 0;
+}
+
+static int test_connect(int client_fds[])
+{
+ struct sockaddr_in addr;
+ socklen_t addr_len;
+ int i, err;
+
+ addr_len = sizeof(addr);
+ addr.sin_family = AF_INET;
+ addr.sin_port = htons(PORT);
+ inet_pton(AF_INET, ADDRESS, &addr.sin_addr.s_addr);
+
+ for (i = 0; i < NUM_CLIENTS; i++) {
+ client_fds[i] = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+ if (CHECK_FAIL(client_fds[i] == -1))
+ return -1;
+
+ err = connect(client_fds[i], (struct sockaddr *)&addr, addr_len);
+ if (CHECK_FAIL(err == -1))
+ return -1;
+ }
+
+ return 0;
+}
+
+static void test_close(int server_fds[], int num)
+{
+ int i;
+
+ for (i = 0; i < num; i++)
+ if (server_fds[i] > 0)
+ close(server_fds[i]);
+}
+
+static int test_accept(int server_fd)
+{
+ struct sockaddr_in addr;
+ socklen_t addr_len;
+ int cnt, client_fd;
+
+ fcntl(server_fd, F_SETFL, O_NONBLOCK);
+ addr_len = sizeof(addr);
+
+ for (cnt = 0; cnt < NUM_CLIENTS; cnt++) {
+ client_fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);
+ if (CHECK_FAIL(client_fd == -1))
+ return -1;
+ }
+
+ return cnt;
+}
+
+
+void test_select_reuseport_migrate(void)
+{
+ struct test_select_reuseport_migrate *skel;
+ int server_fds[NUM_SERVERS] = {0};
+ int client_fds[NUM_CLIENTS] = {0};
+ __u32 duration = 0;
+ int err;
+
+ skel = test_select_reuseport_migrate__open_and_load();
+ if (CHECK_FAIL(!skel))
+ goto destroy;
+
+ err = test_listen(skel, server_fds);
+ if (err)
+ goto close_server;
+
+ err = test_connect(client_fds);
+ if (err)
+ goto close_client;
+
+ test_close(server_fds, NUM_SERVERS - 1);
+
+ err = test_accept(server_fds[NUM_SERVERS - 1]);
+ CHECK(err != NUM_CLIENTS,
+ "accept",
+ "expected (%d) != actual (%d)\n",
+ NUM_CLIENTS, err);
+
+close_client:
+ test_close(client_fds, NUM_CLIENTS);
+
+close_server:
+ test_close(server_fds, NUM_SERVERS);
+
+destroy:
+ test_select_reuseport_migrate__destroy(skel);
+}
new file mode 100644
@@ -0,0 +1,53 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Check if we can migrate child sockets.
+ *
+ * 1. If reuse_md->migration is 0 (SYN packet),
+ * return SK_PASS without selecting a listener.
+ * 2. If reuse_md->migration is not 0 (socket migration),
+ * select a listener (reuseport_map[migrate_map[cookie]])
+ *
+ * Author: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
+ */
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+#define NULL ((void *)0)
+
+struct bpf_map_def SEC("maps") reuseport_map = {
+ .type = BPF_MAP_TYPE_REUSEPORT_SOCKARRAY,
+ .key_size = sizeof(int),
+ .value_size = sizeof(__u64),
+ .max_entries = 256,
+};
+
+struct bpf_map_def SEC("maps") migrate_map = {
+ .type = BPF_MAP_TYPE_HASH,
+ .key_size = sizeof(__u64),
+ .value_size = sizeof(int),
+ .max_entries = 256,
+};
+
+SEC("sk_reuseport/migrate")
+int prog_select_reuseport_migrate(struct sk_reuseport_md *reuse_md)
+{
+ int *key, flags = 0;
+ __u64 cookie;
+
+ if (!reuse_md->migration)
+ return SK_PASS;
+
+ cookie = bpf_get_socket_cookie(reuse_md->sk);
+
+ key = bpf_map_lookup_elem(&migrate_map, &cookie);
+ if (key == NULL)
+ return SK_DROP;
+
+ bpf_sk_select_reuseport(reuse_md, &reuseport_map, key, flags);
+
+ return SK_PASS;
+}
+
+int _version SEC("version") = 1;
+char _license[] SEC("license") = "GPL";