From: Tony Ambardar <tony.ambardar@xxxxxxxxx>
Linux 5.1 implemented 64-bit time types and related syscalls to address the
Y2038 problem generally across archs. Userspace handling of Y2038 varies
with the libc however. While musl libc uses 64-bit time across all 32-bit
and 64-bit platforms, GNU glibc uses 64-bit time on 64-bit platforms but
defaults to 32-bit time on 32-bit platforms unless they "opt-in" to 64-bit
time or explicitly use 64-bit syscalls and time structures.
One specific area is the standard setsockopt() call, SO_TIMESTAMPNS option
used for timestamping, and the related output 'struct timespec'. GNU glibc
defaults as above, also exposing the SO_TIMESTAMPNS_NEW flag to explicitly
use a 64-bit call and 'struct __kernel_timespec'. Since these are not
exposed or needed with musl libc, their use in tc_redirect.c leads to
compile errors building for mips64el/musl:
tc_redirect.c: In function 'rcv_tstamp':
tc_redirect.c:425:32: error: 'SO_TIMESTAMPNS_NEW' undeclared (first use in this function); did you mean 'SO_TIMESTAMPNS'?
425 | cmsg->cmsg_type == SO_TIMESTAMPNS_NEW)
| ^~~~~~~~~~~~~~~~~~
| SO_TIMESTAMPNS
tc_redirect.c:425:32: note: each undeclared identifier is reported only once for each function it appears in
tc_redirect.c: In function 'test_inet_dtime':
tc_redirect.c:491:49: error: 'SO_TIMESTAMPNS_NEW' undeclared (first use in this function); did you mean 'SO_TIMESTAMPNS'?
491 | err = setsockopt(listen_fd, SOL_SOCKET, SO_TIMESTAMPNS_NEW,
| ^~~~~~~~~~~~~~~~~~
| SO_TIMESTAMPNS
However, using SO_TIMESTAMPNS_NEW isn't strictly needed, nor is Y2038 being
explicitly tested. The timestamp checks in tc_redirect.c are simple: the
packet receive timestamp is non-zero and processed/handled in less than 5
seconds.
Switch to using the standard setsockopt() call and SO_TIMESTAMPNS option to
ensure compatibility across glibc and musl libc. In the worst-case, there
is a 5-second window 14 years from now where tc_redirect tests may fail on
32-bit systems. However, we should reasonably expect glibc to adopt a
64-bit mandate rather than the current "opt-in" policy before the Y2038
roll-over.
Fixes: ce6f6cffaeaa ("selftests/bpf: Wait for the netstamp_needed_key static key to be turned on")
Fixes: c803475fd8dd ("bpf: selftests: test skb->tstamp in redirect_neigh")
Signed-off-by: Tony Ambardar <tony.ambardar@xxxxxxxxx>
---
tools/testing/selftests/bpf/prog_tests/tc_redirect.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/tc_redirect.c b/tools/testing/selftests/bpf/prog_tests/tc_redirect.c
index 327d51f59142..53b8ffc943dc 100644
--- a/tools/testing/selftests/bpf/prog_tests/tc_redirect.c
+++ b/tools/testing/selftests/bpf/prog_tests/tc_redirect.c
@@ -471,7 +471,7 @@ static int set_forwarding(bool enable)
static int __rcv_tstamp(int fd, const char *expected, size_t s, __u64 *tstamp)
{
- struct __kernel_timespec pkt_ts = {};
+ struct timespec pkt_ts = {};
char ctl[CMSG_SPACE(sizeof(pkt_ts))];
struct timespec now_ts;
struct msghdr msg = {};
@@ -495,7 +495,7 @@ static int __rcv_tstamp(int fd, const char *expected, size_t s, __u64 *tstamp)
cmsg = CMSG_FIRSTHDR(&msg);
if (cmsg && cmsg->cmsg_level == SOL_SOCKET &&
- cmsg->cmsg_type == SO_TIMESTAMPNS_NEW)
+ cmsg->cmsg_type == SO_TIMESTAMPNS)
memcpy(&pkt_ts, CMSG_DATA(cmsg), sizeof(pkt_ts));
pkt_ns = pkt_ts.tv_sec * NSEC_PER_SEC + pkt_ts.tv_nsec;
@@ -537,9 +537,9 @@ static int wait_netstamp_needed_key(void)
if (!ASSERT_GE(srv_fd, 0, "start_server"))
goto done;
- err = setsockopt(srv_fd, SOL_SOCKET, SO_TIMESTAMPNS_NEW,
+ err = setsockopt(srv_fd, SOL_SOCKET, SO_TIMESTAMPNS,
&opt, sizeof(opt));
- if (!ASSERT_OK(err, "setsockopt(SO_TIMESTAMPNS_NEW)"))
+ if (!ASSERT_OK(err, "setsockopt(SO_TIMESTAMPNS)"))
goto done;
cli_fd = connect_to_fd(srv_fd, TIMEOUT_MILLIS);
@@ -621,9 +621,9 @@ static void test_inet_dtime(int family, int type, const char *addr, __u16 port)
return;
/* Ensure the kernel puts the (rcv) timestamp for all skb */
- err = setsockopt(listen_fd, SOL_SOCKET, SO_TIMESTAMPNS_NEW,
+ err = setsockopt(listen_fd, SOL_SOCKET, SO_TIMESTAMPNS,
&opt, sizeof(opt));
- if (!ASSERT_OK(err, "setsockopt(SO_TIMESTAMPNS_NEW)"))
+ if (!ASSERT_OK(err, "setsockopt(SO_TIMESTAMPNS)"))
goto done;
if (type == SOCK_STREAM) {
--
2.34.1
