summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorPetar Penkov <ppenkov@google.com>2019-08-13 02:30:39 +0300
committerDaniel Borkmann <daniel@iogearbox.net>2019-08-13 17:31:10 +0300
commit9840a4ffcf0b26e08472ed53d176a6a0f1d4c498 (patch)
tree5b8fa71c24e314f5c38f7ab7bab4212e30f24ecf
parentd66fa3c70e598746a907e5db5ed024035e01817a (diff)
downloadlinux-9840a4ffcf0b26e08472ed53d176a6a0f1d4c498.tar.xz
selftests/bpf: fix race in flow dissector tests
Since the "last_dissection" map holds only the flow keys for the most recent packet, there is a small race in the skb-less flow dissector tests if a new packet comes between transmitting the test packet, and reading its keys from the map. If this happens, the test packet keys will be overwritten and the test will fail. Changing the "last_dissection" map to a hash map, keyed on the source/dest port pair resolves this issue. Additionally, let's clear the last test results from the map between tests to prevent previous test cases from interfering with the following test cases. Fixes: 0905beec9f52 ("selftests/bpf: run flow dissector tests in skb-less mode") Signed-off-by: Petar Penkov <ppenkov@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
-rw-r--r--tools/testing/selftests/bpf/prog_tests/flow_dissector.c22
-rw-r--r--tools/testing/selftests/bpf/progs/bpf_flow.c13
2 files changed, 27 insertions, 8 deletions
diff --git a/tools/testing/selftests/bpf/prog_tests/flow_dissector.c b/tools/testing/selftests/bpf/prog_tests/flow_dissector.c
index 700d73d2f22a..6892b88ae065 100644
--- a/tools/testing/selftests/bpf/prog_tests/flow_dissector.c
+++ b/tools/testing/selftests/bpf/prog_tests/flow_dissector.c
@@ -109,6 +109,8 @@ struct test tests[] = {
.iph.protocol = IPPROTO_TCP,
.iph.tot_len = __bpf_constant_htons(MAGIC_BYTES),
.tcp.doff = 5,
+ .tcp.source = 80,
+ .tcp.dest = 8080,
},
.keys = {
.nhoff = ETH_HLEN,
@@ -116,6 +118,8 @@ struct test tests[] = {
.addr_proto = ETH_P_IP,
.ip_proto = IPPROTO_TCP,
.n_proto = __bpf_constant_htons(ETH_P_IP),
+ .sport = 80,
+ .dport = 8080,
},
},
{
@@ -125,6 +129,8 @@ struct test tests[] = {
.iph.nexthdr = IPPROTO_TCP,
.iph.payload_len = __bpf_constant_htons(MAGIC_BYTES),
.tcp.doff = 5,
+ .tcp.source = 80,
+ .tcp.dest = 8080,
},
.keys = {
.nhoff = ETH_HLEN,
@@ -132,6 +138,8 @@ struct test tests[] = {
.addr_proto = ETH_P_IPV6,
.ip_proto = IPPROTO_TCP,
.n_proto = __bpf_constant_htons(ETH_P_IPV6),
+ .sport = 80,
+ .dport = 8080,
},
},
{
@@ -143,6 +151,8 @@ struct test tests[] = {
.iph.protocol = IPPROTO_TCP,
.iph.tot_len = __bpf_constant_htons(MAGIC_BYTES),
.tcp.doff = 5,
+ .tcp.source = 80,
+ .tcp.dest = 8080,
},
.keys = {
.nhoff = ETH_HLEN + VLAN_HLEN,
@@ -150,6 +160,8 @@ struct test tests[] = {
.addr_proto = ETH_P_IP,
.ip_proto = IPPROTO_TCP,
.n_proto = __bpf_constant_htons(ETH_P_IP),
+ .sport = 80,
+ .dport = 8080,
},
},
{
@@ -161,6 +173,8 @@ struct test tests[] = {
.iph.nexthdr = IPPROTO_TCP,
.iph.payload_len = __bpf_constant_htons(MAGIC_BYTES),
.tcp.doff = 5,
+ .tcp.source = 80,
+ .tcp.dest = 8080,
},
.keys = {
.nhoff = ETH_HLEN + VLAN_HLEN * 2,
@@ -169,6 +183,8 @@ struct test tests[] = {
.addr_proto = ETH_P_IPV6,
.ip_proto = IPPROTO_TCP,
.n_proto = __bpf_constant_htons(ETH_P_IPV6),
+ .sport = 80,
+ .dport = 8080,
},
},
{
@@ -487,7 +503,8 @@ void test_flow_dissector(void)
BPF_FLOW_DISSECTOR_F_PARSE_1ST_FRAG;
struct bpf_prog_test_run_attr tattr = {};
struct bpf_flow_keys flow_keys = {};
- __u32 key = 0;
+ __u32 key = (__u32)(tests[i].keys.sport) << 16 |
+ tests[i].keys.dport;
/* For skb-less case we can't pass input flags; run
* only the tests that have a matching set of flags.
@@ -504,6 +521,9 @@ void test_flow_dissector(void)
CHECK_ATTR(err, tests[i].name, "skb-less err %d\n", err);
CHECK_FLOW_KEYS(tests[i].name, flow_keys, tests[i].keys);
+
+ err = bpf_map_delete_elem(keys_fd, &key);
+ CHECK_ATTR(err, tests[i].name, "bpf_map_delete_elem %d\n", err);
}
bpf_prog_detach(prog_fd, BPF_FLOW_DISSECTOR);
diff --git a/tools/testing/selftests/bpf/progs/bpf_flow.c b/tools/testing/selftests/bpf/progs/bpf_flow.c
index 08bd8b9d58d0..040a44206f29 100644
--- a/tools/testing/selftests/bpf/progs/bpf_flow.c
+++ b/tools/testing/selftests/bpf/progs/bpf_flow.c
@@ -65,8 +65,8 @@ struct {
} jmp_table SEC(".maps");
struct {
- __uint(type, BPF_MAP_TYPE_ARRAY);
- __uint(max_entries, 1);
+ __uint(type, BPF_MAP_TYPE_HASH);
+ __uint(max_entries, 1024);
__type(key, __u32);
__type(value, struct bpf_flow_keys);
} last_dissection SEC(".maps");
@@ -74,12 +74,11 @@ struct {
static __always_inline int export_flow_keys(struct bpf_flow_keys *keys,
int ret)
{
- struct bpf_flow_keys *val;
- __u32 key = 0;
+ __u32 key = (__u32)(keys->sport) << 16 | keys->dport;
+ struct bpf_flow_keys val;
- val = bpf_map_lookup_elem(&last_dissection, &key);
- if (val)
- memcpy(val, keys, sizeof(*val));
+ memcpy(&val, keys, sizeof(val));
+ bpf_map_update_elem(&last_dissection, &key, &val, BPF_ANY);
return ret;
}