Introduce tail adjustment functionality in xskxceiver using
bpf_xdp_adjust_tail(). Add `xsk_xdp_adjust_tail` to modify packet sizes
and drop unmodified packets. Implement `is_adjust_tail_supported` to check
helper availability. Develop packet resizing tests, including shrinking
and growing scenarios, with functions for both single-buffer and
multi-buffer cases. Update the test framework to handle various scenarios
and adjust MTU settings. These changes enhance the testing of packet tail
adjustments, improving AF_XDP framework reliability.
Signed-off-by: Tushar Vyavahare <tushar.vyavahare@xxxxxxxxx>
---
.../selftests/bpf/progs/xsk_xdp_progs.c | 48 +++++++
tools/testing/selftests/bpf/xsk_xdp_common.h | 1 +
tools/testing/selftests/bpf/xskxceiver.c | 118 +++++++++++++++++-
tools/testing/selftests/bpf/xskxceiver.h | 2 +
4 files changed, 167 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/bpf/progs/xsk_xdp_progs.c b/tools/testing/selftests/bpf/progs/xsk_xdp_progs.c
index ccde6a4c6319..2e8e2faf17e0 100644
--- a/tools/testing/selftests/bpf/progs/xsk_xdp_progs.c
+++ b/tools/testing/selftests/bpf/progs/xsk_xdp_progs.c
@@ -4,6 +4,8 @@
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include <linux/if_ether.h>
+#include <linux/ip.h>
+#include <linux/errno.h>
#include "xsk_xdp_common.h"
struct {
@@ -70,4 +72,50 @@ SEC("xdp") int xsk_xdp_shared_umem(struct xdp_md *xdp)
return bpf_redirect_map(&xsk, idx, XDP_DROP);
}
+SEC("xdp.frags") int xsk_xdp_adjust_tail(struct xdp_md *xdp)
+{
+ __u32 buff_len, curr_buff_len;
+ int ret;
+
+ buff_len = bpf_xdp_get_buff_len(xdp);
+ if (buff_len == 0)
+ return XDP_DROP;
+
+ ret = bpf_xdp_adjust_tail(xdp, count);
+ if (ret < 0) {
+ /* Handle unsupported cases */
+ if (ret == -EOPNOTSUPP) {
+ /* Set count to -EOPNOTSUPP to indicate to userspace that this case is
+ * unsupported
+ */
+ count = -EOPNOTSUPP;
+ return bpf_redirect_map(&xsk, 0, XDP_DROP);
+ }
+
+ return XDP_DROP;
+ }
+
+ curr_buff_len = bpf_xdp_get_buff_len(xdp);
+ if (curr_buff_len != buff_len + count)
+ return XDP_DROP;
+
+ if (curr_buff_len > buff_len) {
+ __u32 *pkt_data = (void *)(long)xdp->data;
+ __u32 len, words_to_end, seq_num;
+
+ len = curr_buff_len - PKT_HDR_ALIGN;
+ words_to_end = len / sizeof(*pkt_data) - 1;
+ seq_num = words_to_end;
+
+ /* Convert sequence number to network byte order. Store this in the last 4 bytes of
+ * the packet. Use 'count' to determine the position at the end of the packet for
+ * storing the sequence number.
+ */
+ seq_num = __constant_htonl(words_to_end);
+ bpf_xdp_store_bytes(xdp, curr_buff_len - count, &seq_num, sizeof(seq_num));
+ }
+
+ return bpf_redirect_map(&xsk, 0, XDP_DROP);
+}
+
char _license[] SEC("license") = "GPL";
diff --git a/tools/testing/selftests/bpf/xsk_xdp_common.h b/tools/testing/selftests/bpf/xsk_xdp_common.h
index 5a6f36f07383..45810ff552da 100644
--- a/tools/testing/selftests/bpf/xsk_xdp_common.h
+++ b/tools/testing/selftests/bpf/xsk_xdp_common.h
@@ -4,6 +4,7 @@
#define XSK_XDP_COMMON_H_
#define MAX_SOCKETS 2
+#define PKT_HDR_ALIGN (sizeof(struct ethhdr) + 2) /* Just to align the data in the packet */
struct xdp_info {
__u64 count;
diff --git a/tools/testing/selftests/bpf/xskxceiver.c b/tools/testing/selftests/bpf/xskxceiver.c
index d60ee6a31c09..ee196b638662 100644
--- a/tools/testing/selftests/bpf/xskxceiver.c
+++ b/tools/testing/selftests/bpf/xskxceiver.c
@@ -524,6 +524,8 @@ static void __test_spec_init(struct test_spec *test, struct ifobject *ifobj_tx,
test->nb_sockets = 1;
test->fail = false;
test->set_ring = false;
+ test->adjust_tail = false;
+ test->adjust_tail_support = false;
test->mtu = MAX_ETH_PKT_SIZE;
test->xdp_prog_rx = ifobj_rx->xdp_progs->progs.xsk_def_prog;
test->xskmap_rx = ifobj_rx->xdp_progs->maps.xsk;
@@ -992,6 +994,31 @@ static bool is_metadata_correct(struct pkt *pkt, void *buffer, u64 addr)
return true;
}
+static bool is_adjust_tail_supported(struct xsk_xdp_progs *skel_rx)
+{
+ struct bpf_map *data_map;
+ int value = 0;
+ int key = 0;
+ int ret;
+
+ data_map = bpf_object__find_map_by_name(skel_rx->obj, "xsk_xdp_.bss");
+ if (!data_map || !bpf_map__is_internal(data_map)) {
+ ksft_print_msg("Error: could not find bss section of XDP program\n");
+ exit_with_error(errno);
+ }
+
+ ret = bpf_map_lookup_elem(bpf_map__fd(data_map), &key, &value);
+ if (ret) {
+ ksft_print_msg("Error: bpf_map_lookup_elem failed with error %d\n", ret);
+ return false;
+ }
+
+ /* Set the 'count' variable to -EOPNOTSUPP in the XDP program if the adjust_tail helper is
+ * not supported. Skip the adjust_tail test case in this scenario.
+ */
+ return value != -EOPNOTSUPP;
+}
+
static bool is_frag_valid(struct xsk_umem_info *umem, u64 addr, u32 len, u32 expected_pkt_nb,
u32 bytes_processed)
{
@@ -1768,8 +1795,13 @@ static void *worker_testapp_validate_rx(void *arg)
if (!err && ifobject->validation_func)
err = ifobject->validation_func(ifobject);
- if (err)
- report_failure(test);
+
+ if (err) {
+ if (test->adjust_tail && !is_adjust_tail_supported(ifobject->xdp_progs))
+ test->adjust_tail_support = false;
+ else
+ report_failure(test);
+ }
pthread_exit(NULL);
}
@@ -2516,6 +2548,84 @@ static int testapp_hw_sw_max_ring_size(struct test_spec *test)
return testapp_validate_traffic(test);
}
+static int testapp_xdp_adjust_tail(struct test_spec *test, int count)
+{
+ struct xsk_xdp_progs *skel_rx = test->ifobj_rx->xdp_progs;
+ struct xsk_xdp_progs *skel_tx = test->ifobj_tx->xdp_progs;
+ struct bpf_map *data_map;
+ int key = 0;
+
+ test_spec_set_xdp_prog(test, skel_rx->progs.xsk_xdp_adjust_tail,
+ skel_tx->progs.xsk_xdp_adjust_tail,
+ skel_rx->maps.xsk, skel_tx->maps.xsk);
+
+ data_map = bpf_object__find_map_by_name(skel_rx->obj, "xsk_xdp_.bss");
+ if (!data_map || !bpf_map__is_internal(data_map)) {
+ ksft_print_msg("Error: could not find bss section of XDP program\n");
+ return TEST_FAILURE;
+ }
+
+ if (bpf_map_update_elem(bpf_map__fd(data_map), &key, &count, BPF_ANY)) {
+ ksft_print_msg("Error: could not update count element\n");
+ return TEST_FAILURE;
+ }
+
+ return testapp_validate_traffic(test);
+}
+
+static int testapp_adjust_tail(struct test_spec *test, u32 value, u32 pkt_len)
+{
+ u32 pkt_cnt = DEFAULT_BATCH_SIZE;
+ int ret;
+
+ test->adjust_tail_support = true;
+ test->adjust_tail = true;
+ test->total_steps = 1;
+
+ pkt_stream_replace_ifobject(test->ifobj_tx, pkt_cnt, pkt_len);
+ pkt_stream_replace_ifobject(test->ifobj_rx, pkt_cnt, pkt_len + value);
+
+ ret = testapp_xdp_adjust_tail(test, value);
+ if (ret)
+ return ret;
+
+ if (!test->adjust_tail_support) {
+ ksft_test_result_skip("%s %sResize pkt with bpf_xdp_adjust_tail() not supported\n",
+ mode_string(test), busy_poll_string(test));
+ return TEST_SKIP;
+ }
+
+ return 0;
+}
+
+static int testapp_adjust_tail_common(struct test_spec *test, int adjust_value, u32 len,
+ bool set_mtu)
+{
+ if (set_mtu)
+ test->mtu = MAX_ETH_JUMBO_SIZE;
+ return testapp_adjust_tail(test, adjust_value, len);
+}
+
+static int testapp_adjust_tail_shrink(struct test_spec *test)
+{
+ return testapp_adjust_tail_common(test, -4, MIN_PKT_SIZE, false);
+}
+
+static int testapp_adjust_tail_shrink_mb(struct test_spec *test)
+{
+ return testapp_adjust_tail_common(test, -4, XSK_RING_PROD__DEFAULT_NUM_DESCS * 3, true);
+}
+
+static int testapp_adjust_tail_grow(struct test_spec *test)
+{
+ return testapp_adjust_tail_common(test, 4, MIN_PKT_SIZE, false);
+}
+
+static int testapp_adjust_tail_grow_mb(struct test_spec *test)
+{
+ return testapp_adjust_tail_common(test, 4, XSK_RING_PROD__DEFAULT_NUM_DESCS * 3, true);
+}
+
static void run_pkt_test(struct test_spec *test)
{
int ret;
@@ -2622,6 +2732,10 @@ static const struct test_spec tests[] = {
{.name = "TOO_MANY_FRAGS", .test_func = testapp_too_many_frags},
{.name = "HW_SW_MIN_RING_SIZE", .test_func = testapp_hw_sw_min_ring_size},
{.name = "HW_SW_MAX_RING_SIZE", .test_func = testapp_hw_sw_max_ring_size},
+ {.name = "XDP_ADJUST_TAIL_SHRINK", .test_func = testapp_adjust_tail_shrink},
+ {.name = "XDP_ADJUST_TAIL_SHRINK_MULTI_BUFF", .test_func = testapp_adjust_tail_shrink_mb},
+ {.name = "XDP_ADJUST_TAIL_GROW", .test_func = testapp_adjust_tail_grow},
+ {.name = "XDP_ADJUST_TAIL_GROW_MULTI_BUFF", .test_func = testapp_adjust_tail_grow_mb},
};
static void print_tests(void)
diff --git a/tools/testing/selftests/bpf/xskxceiver.h b/tools/testing/selftests/bpf/xskxceiver.h
index e46e823f6a1a..67fc44b2813b 100644
--- a/tools/testing/selftests/bpf/xskxceiver.h
+++ b/tools/testing/selftests/bpf/xskxceiver.h
@@ -173,6 +173,8 @@ struct test_spec {
u16 nb_sockets;
bool fail;
bool set_ring;
+ bool adjust_tail;
+ bool adjust_tail_support;
enum test_mode mode;
char name[MAX_TEST_NAME_SIZE];
};
--
2.34.1
