selftests/xsk: Add a test for shared umem feature

Add a new test for testing shared umem feature. This is accomplished by
adding a new XDP program and using the multiple sockets.

The new XDP program redirects the packets based on the destination MAC
address.
Signed-off-by: Tushar Vyavahare <tushar.vyavahare@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20230927135241.2287547-9-tushar.vyavahare@intel.com

tools/testing/selftests/bpf/progs/xsk_xdp_progs.c

@@ -3,11 +3,12 @@
 
 #include <linux/bpf.h>
 #include <bpf/bpf_helpers.h>
+#include <linux/if_ether.h>
 #include "xsk_xdp_common.h"
 
 struct {
 	__uint(type, BPF_MAP_TYPE_XSKMAP);
-	__uint(max_entries, 1);
+	__uint(max_entries, 2);
 	__uint(key_size, sizeof(int));
 	__uint(value_size, sizeof(int));
 } xsk SEC(".maps");
@@ -52,4 +53,21 @@ SEC("xdp.frags") int xsk_xdp_populate_metadata(struct xdp_md *xdp)
 	return bpf_redirect_map(&xsk, 0, XDP_DROP);
 }
 
+SEC("xdp") int xsk_xdp_shared_umem(struct xdp_md *xdp)
+{
+	void *data = (void *)(long)xdp->data;
+	void *data_end = (void *)(long)xdp->data_end;
+	struct ethhdr *eth = data;
+
+	if (eth + 1 > data_end)
+		return XDP_DROP;
+
+	/* Redirecting packets based on the destination MAC address */
+	idx = ((unsigned int)(eth->h_dest[5])) / 2;
+	if (idx > MAX_SOCKETS)
+		return XDP_DROP;
+
+	return bpf_redirect_map(&xsk, idx, XDP_DROP);
+}
+
 char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/xsk_xdp_common.h

@@ -3,6 +3,8 @@
 #ifndef XSK_XDP_COMMON_H_
 #define XSK_XDP_COMMON_H_
 
+#define MAX_SOCKETS 2
+
 struct xdp_info {
 	__u64 count;
 } __attribute__((aligned(32)));

tools/testing/selftests/bpf/xskxceiver.c

@@ -651,7 +651,7 @@ static u32 pkt_get_buffer_len(struct xsk_umem_info *umem, u32 len)
 	return ceil_u32(len, umem->frame_size) * umem->frame_size;
 }
 
-static struct pkt_stream *pkt_stream_generate(u32 nb_pkts, u32 pkt_len)
+static struct pkt_stream *__pkt_stream_generate(u32 nb_pkts, u32 pkt_len, u32 nb_start, u32 nb_off)
 {
 	struct pkt_stream *pkt_stream;
 	u32 i;
@@ -666,12 +666,17 @@ static struct pkt_stream *pkt_stream_generate(u32 nb_pkts, u32 pkt_len)
 		struct pkt *pkt = &pkt_stream->pkts[i];
 
 		pkt_set(pkt_stream, pkt, 0, pkt_len);
-		pkt->pkt_nb = i;
+		pkt->pkt_nb = nb_start + i * nb_off;
 	}
 
 	return pkt_stream;
 }
 
+static struct pkt_stream *pkt_stream_generate(u32 nb_pkts, u32 pkt_len)
+{
+	return __pkt_stream_generate(nb_pkts, pkt_len, 0, 1);
+}
+
 static struct pkt_stream *pkt_stream_clone(struct pkt_stream *pkt_stream)
 {
 	return pkt_stream_generate(pkt_stream->nb_pkts, pkt_stream->pkts[0].len);
@@ -721,6 +726,24 @@ static void pkt_stream_receive_half(struct test_spec *test)
 	pkt_stream->nb_valid_entries /= 2;
 }
 
+static void pkt_stream_even_odd_sequence(struct test_spec *test)
+{
+	struct pkt_stream *pkt_stream;
+	u32 i;
+
+	for (i = 0; i < test->nb_sockets; i++) {
+		pkt_stream = test->ifobj_tx->xsk_arr[i].pkt_stream;
+		pkt_stream = __pkt_stream_generate(pkt_stream->nb_pkts / 2,
+						   pkt_stream->pkts[0].len, i, 2);
+		test->ifobj_tx->xsk_arr[i].pkt_stream = pkt_stream;
+
+		pkt_stream = test->ifobj_rx->xsk_arr[i].pkt_stream;
+		pkt_stream = __pkt_stream_generate(pkt_stream->nb_pkts / 2,
+						   pkt_stream->pkts[0].len, i, 2);
+		test->ifobj_rx->xsk_arr[i].pkt_stream = pkt_stream;
+	}
+}
+
 static u64 pkt_get_addr(struct pkt *pkt, struct xsk_umem_info *umem)
 {
 	if (!pkt->valid)
@@ -1584,6 +1607,7 @@ static void thread_common_ops(struct test_spec *test, struct ifobject *ifobject)
 	LIBBPF_OPTS(bpf_xdp_query_opts, opts);
 	void *bufs;
 	int ret;
+	u32 i;
 
 	if (ifobject->umem->unaligned_mode)
 		mmap_flags |= MAP_HUGETLB | MAP_HUGE_2MB;
@@ -1608,9 +1632,12 @@ static void thread_common_ops(struct test_spec *test, struct ifobject *ifobject)
 
 	xsk_populate_fill_ring(ifobject->umem, ifobject->xsk->pkt_stream, ifobject->use_fill_ring);
 
-	ret = xsk_update_xskmap(ifobject->xskmap, ifobject->xsk->xsk, 0);
+	for (i = 0; i < test->nb_sockets; i++) {
+		ifobject->xsk = &ifobject->xsk_arr[i];
+		ret = xsk_update_xskmap(ifobject->xskmap, ifobject->xsk->xsk, i);
 		if (ret)
 			exit_with_error(errno);
+	}
 }
 
 static void *worker_testapp_validate_tx(void *arg)
@@ -2111,6 +2138,23 @@ static int testapp_xdp_metadata_copy(struct test_spec *test)
 	return testapp_validate_traffic(test);
 }
 
+static int testapp_xdp_shared_umem(struct test_spec *test)
+{
+	struct xsk_xdp_progs *skel_rx = test->ifobj_rx->xdp_progs;
+	struct xsk_xdp_progs *skel_tx = test->ifobj_tx->xdp_progs;
+
+	test->total_steps = 1;
+	test->nb_sockets = 2;
+
+	test_spec_set_xdp_prog(test, skel_rx->progs.xsk_xdp_shared_umem,
+			       skel_tx->progs.xsk_xdp_shared_umem,
+			       skel_rx->maps.xsk, skel_tx->maps.xsk);
+
+	pkt_stream_even_odd_sequence(test);
+
+	return testapp_validate_traffic(test);
+}
+
 static int testapp_poll_txq_tmout(struct test_spec *test)
 {
 	test->ifobj_tx->use_poll = true;
@@ -2412,6 +2456,7 @@ static const struct test_spec tests[] = {
 	{.name = "STAT_FILL_EMPTY", .test_func = testapp_stats_fill_empty},
 	{.name = "XDP_PROG_CLEANUP", .test_func = testapp_xdp_prog_cleanup},
 	{.name = "XDP_DROP_HALF", .test_func = testapp_xdp_drop},
+	{.name = "XDP_SHARED_UMEM", .test_func = testapp_xdp_shared_umem},
 	{.name = "XDP_METADATA_COPY", .test_func = testapp_xdp_metadata},
 	{.name = "XDP_METADATA_COPY_MULTI_BUFF", .test_func = testapp_xdp_metadata_mb},
 	{.name = "SEND_RECEIVE_9K_PACKETS", .test_func = testapp_send_receive_mb},

tools/testing/selftests/bpf/xskxceiver.h

@@ -8,6 +8,7 @@
 #include <limits.h>
 
 #include "xsk_xdp_progs.skel.h"
+#include "xsk_xdp_common.h"
 
 #ifndef SOL_XDP
 #define SOL_XDP 283
@@ -35,7 +36,6 @@
 #define TEST_SKIP 2
 #define MAX_INTERFACES 2
 #define MAX_INTERFACE_NAME_CHARS 16
-#define MAX_SOCKETS 2
 #define MAX_TEST_NAME_SIZE 48
 #define MAX_TEARDOWN_ITER 10
 #define PKT_HDR_SIZE (sizeof(struct ethhdr) + 2) /* Just to align the data in the packet */