Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-22 04:02:20 +00:00
Code Issues Packages Projects Releases Wiki Activity

selftests/bpf: Wait for the netstamp_needed_key static key to be turned on

Browse Source 
After the previous patch that speeded up the test (by avoiding neigh
discovery in IPv6), the BPF CI occasionally hits this error:

rcv tstamp unexpected pkt rcv tstamp: actual 0 == expected 0

The test complains about the cmsg returned from the recvmsg() does not
have the rcv timestamp. Setting skb->tstamp or not is
controlled by a kernel static key "netstamp_needed_key". The static
key is enabled whenever this is at least one sk with the SOCK_TIMESTAMP
set.

The test_redirect_dtime does use setsockopt() to turn on
the SOCK_TIMESTAMP for the reading sk. In the kernel
net_enable_timestamp() has a delay to enable the "netstamp_needed_key"
when CONFIG_JUMP_LABEL is set. This potential delay is the likely reason
for packet missing rcv timestamp occasionally.

This patch is to create udp sockets with SOCK_TIMESTAMP set.
It sends and receives some packets until the received packet
has a rcv timestamp. It currently retries at most 5 times with 1s
in between. This should be enough to wait for the "netstamp_needed_key".
It then holds on to the socket and only closes it at the end of the test.
This guarantees that the test has the "netstamp_needed_key" key turned
on from the beginning.

To simplify the udp sockets setup, they are sending/receiving packets
in the same netns (ns_dst is used) and communicate over the "lo" dev.
Hence, the patch enables the "lo" dev in the ns_dst.

Fixes: c803475fd8 ("bpf: selftests: test skb->tstamp in redirect_neigh")
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240120060518.3604920-2-martin.lau@linux.dev
This commit is contained in:
Martin KaFai Lau 2024-01-19 22:05:18 -08:00 committed by Andrii Nakryiko
parent 177f1d083a
commit ce6f6cffae
1 changed files with 75 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

79
tools/testing/selftests/bpf/prog_tests/tc_redirect.c
View File

@ -291,6 +291,7 @@ static int netns_setup_links_and_routes(struct netns_setup_result *result)
SYS(fail, "ip addr add " IP4_DST "/32 dev dst");
SYS(fail, "ip addr add " IP6_DST "/128 dev dst nodad");
SYS(fail, "ip link set dev dst up");
SYS(fail, "ip link set dev lo up");
SYS(fail, "ip route add " IP4_SRC "/32 dev dst scope global");
SYS(fail, "ip route add " IP4_NET "/16 dev dst scope global");
@ -468,7 +469,7 @@ static int set_forwarding(bool enable)
return 0;
}
static void rcv_tstamp(int fd, const char *expected, size_t s)
static int __rcv_tstamp(int fd, const char *expected, size_t s, __u64 *tstamp)
{
struct __kernel_timespec pkt_ts = {};
char ctl[CMSG_SPACE(sizeof(pkt_ts))];
@ -489,7 +490,7 @@ static void rcv_tstamp(int fd, const char *expected, size_t s)
ret = recvmsg(fd, &msg, 0);
if (!ASSERT_EQ(ret, s, "recvmsg"))
return;
return -1;
ASSERT_STRNEQ(data, expected, s, "expected rcv data");
cmsg = CMSG_FIRSTHDR(&msg);
@ -498,6 +499,12 @@ static void rcv_tstamp(int fd, const char *expected, size_t s)
memcpy(&pkt_ts, CMSG_DATA(cmsg), sizeof(pkt_ts));
pkt_ns = pkt_ts.tv_sec * NSEC_PER_SEC + pkt_ts.tv_nsec;
if (tstamp) {
/* caller will check the tstamp itself */
*tstamp = pkt_ns;
return 0;
}
ASSERT_NEQ(pkt_ns, 0, "pkt rcv tstamp");
ret = clock_gettime(CLOCK_REALTIME, &now_ts);
@ -507,6 +514,60 @@ static void rcv_tstamp(int fd, const char *expected, size_t s)
if (ASSERT_GE(now_ns, pkt_ns, "check rcv tstamp"))
ASSERT_LT(now_ns - pkt_ns, 5 * NSEC_PER_SEC,
"check rcv tstamp");
return 0;
}
static void rcv_tstamp(int fd, const char *expected, size_t s)
{
__rcv_tstamp(fd, expected, s, NULL);
}
static int wait_netstamp_needed_key(void)
{
int opt = 1, srv_fd = -1, cli_fd = -1, nretries = 0, err, n;
char buf[] = "testing testing";
struct nstoken *nstoken;
__u64 tstamp = 0;
nstoken = open_netns(NS_DST);
if (!nstoken)
return -1;
srv_fd = start_server(AF_INET6, SOCK_DGRAM, "::1", 0, 0);
if (!ASSERT_GE(srv_fd, 0, "start_server"))
goto done;
err = setsockopt(srv_fd, SOL_SOCKET, SO_TIMESTAMPNS_NEW,
&opt, sizeof(opt));
if (!ASSERT_OK(err, "setsockopt(SO_TIMESTAMPNS_NEW)"))
goto done;
cli_fd = connect_to_fd(srv_fd, TIMEOUT_MILLIS);
if (!ASSERT_GE(cli_fd, 0, "connect_to_fd"))
goto done;
again:
n = write(cli_fd, buf, sizeof(buf));
if (!ASSERT_EQ(n, sizeof(buf), "send to server"))
goto done;
err = __rcv_tstamp(srv_fd, buf, sizeof(buf), &tstamp);
if (!ASSERT_OK(err, "__rcv_tstamp"))
goto done;
if (!tstamp && nretries++ < 5) {
sleep(1);
printf("netstamp_needed_key retry#%d\n", nretries);
goto again;
}
done:
if (!tstamp && srv_fd != -1) {
close(srv_fd);
srv_fd = -1;
}
if (cli_fd != -1)
close(cli_fd);
close_netns(nstoken);
return srv_fd;
}
static void snd_tstamp(int fd, char *b, size_t s)
@ -843,11 +904,20 @@ static void test_tc_redirect_dtime(struct netns_setup_result *setup_result)
{
struct test_tc_dtime *skel;
struct nstoken *nstoken;
int err;
int hold_tstamp_fd, err;
/* Hold a sk with the SOCK_TIMESTAMP set to ensure there
* is no delay in the kernel net_enable_timestamp().
* This ensures the following tests must have
* non zero rcv tstamp in the recvmsg().
*/
hold_tstamp_fd = wait_netstamp_needed_key();
if (!ASSERT_GE(hold_tstamp_fd, 0, "wait_netstamp_needed_key"))
return;
skel = test_tc_dtime__open();
if (!ASSERT_OK_PTR(skel, "test_tc_dtime__open"))
return;
goto done;
skel->rodata->IFINDEX_SRC = setup_result->ifindex_src_fwd;
skel->rodata->IFINDEX_DST = setup_result->ifindex_dst_fwd;
@ -892,6 +962,7 @@ static void test_tc_redirect_dtime(struct netns_setup_result *setup_result)
done:
test_tc_dtime__destroy(skel);
close(hold_tstamp_fd);
}
static void test_tc_redirect_neigh_fib(struct netns_setup_result *setup_result)