On Mon, May 10, 2021 at 12:44:33PM +0900, Kuniyuki Iwashima wrote: > diff --git a/tools/testing/selftests/bpf/network_helpers.c b/tools/testing/selftests/bpf/network_helpers.c > index 12ee40284da0..2060bc122c53 100644 [ ... ] > +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_GE(*saved_len, 1, "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")) Is it to trigger the tcp_try_fastopen() case? I am not sure it is enough. At least, I think not for the very first connection before the cookie is saved. The second run of the test may be able to trigger it. setsockopt(TCP_FASTOPEN_NO_COOKIE) or another value in the "/proc/sys/net/ipv4/tcp_fastopen" (ip-sysctl.rst) may be needed. > + err = -1; > + } > + > +close: > + close(fd); > + > + return err; > +} > + [ ... ] > 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..72978b5d1fcb > --- /dev/null > +++ b/tools/testing/selftests/bpf/progs/test_migrate_reuseport.c > @@ -0,0 +1,67 @@ > +// 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"); > + > +int migrated_at_close SEC(".data"); > +int migrated_at_send_synack SEC(".data"); > +int migrated_at_recv_ack SEC(".data"); int migrated_at_close = 0; int migrated_at_send_synack = 0; int migrated_at_recv_ack = 0; and then use skel->bss->migrated_at_* in migrate_reuseport.c.