selftests, xsk: Fix bpf_res cleanup test

After commit 710ad98c ("veth: Do not record rx queue hint in veth_xmit"),
veth no longer receives traffic on the same queue as it was sent on. This
breaks the bpf_res test for the AF_XDP selftests as the socket tied to
queue 1 will not receive traffic anymore.

Modify the test so that two sockets are tied to queue id 0 using a shared
umem instead. When killing the first socket enter the second socket into
the xskmap so that traffic will flow to it. This will still test that the
resources are not cleaned up until after the second socket dies, without
having to rely on veth supporting rx_queue hints.
Reported-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20220125082945.26179-1-magnus.karlsson@gmail.com

tools/testing/selftests/bpf/xdpxceiver.c

@@ -266,22 +266,24 @@ static int xsk_configure_umem(struct xsk_umem_info *umem, void *buffer, u64 size
 }
 
 static int xsk_configure_socket(struct xsk_socket_info *xsk, struct xsk_umem_info *umem,
-				struct ifobject *ifobject, u32 qid)
+				struct ifobject *ifobject, bool shared)
 {
-	struct xsk_socket_config cfg;
+	struct xsk_socket_config cfg = {};
 	struct xsk_ring_cons *rxr;
 	struct xsk_ring_prod *txr;
 
 	xsk->umem = umem;
 	cfg.rx_size = xsk->rxqsize;
 	cfg.tx_size = XSK_RING_PROD__DEFAULT_NUM_DESCS;
-	cfg.libbpf_flags = 0;
+	cfg.libbpf_flags = XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD;
 	cfg.xdp_flags = ifobject->xdp_flags;
 	cfg.bind_flags = ifobject->bind_flags;
+	if (shared)
+		cfg.bind_flags |= XDP_SHARED_UMEM;
 
 	txr = ifobject->tx_on ? &xsk->tx : NULL;
 	rxr = ifobject->rx_on ? &xsk->rx : NULL;
-	return xsk_socket__create(&xsk->xsk, ifobject->ifname, qid, umem->umem, rxr, txr, &cfg);
+	return xsk_socket__create(&xsk->xsk, ifobject->ifname, 0, umem->umem, rxr, txr, &cfg);
 }
 
 static struct option long_options[] = {
@@ -387,7 +389,6 @@ static void __test_spec_init(struct test_spec *test, struct ifobject *ifobj_tx,
 	for (i = 0; i < MAX_INTERFACES; i++) {
 		struct ifobject *ifobj = i ? ifobj_rx : ifobj_tx;
 
-		ifobj->umem = &ifobj->umem_arr[0];
 		ifobj->xsk = &ifobj->xsk_arr[0];
 		ifobj->use_poll = false;
 		ifobj->pacing_on = true;
@@ -401,11 +402,12 @@ static void __test_spec_init(struct test_spec *test, struct ifobject *ifobj_tx,
 			ifobj->tx_on = false;
 		}
 
+		memset(ifobj->umem, 0, sizeof(*ifobj->umem));
+		ifobj->umem->num_frames = DEFAULT_UMEM_BUFFERS;
+		ifobj->umem->frame_size = XSK_UMEM__DEFAULT_FRAME_SIZE;
+
 		for (j = 0; j < MAX_SOCKETS; j++) {
-			memset(&ifobj->umem_arr[j], 0, sizeof(ifobj->umem_arr[j]));
 			memset(&ifobj->xsk_arr[j], 0, sizeof(ifobj->xsk_arr[j]));
-			ifobj->umem_arr[j].num_frames = DEFAULT_UMEM_BUFFERS;
-			ifobj->umem_arr[j].frame_size = XSK_UMEM__DEFAULT_FRAME_SIZE;
 			ifobj->xsk_arr[j].rxqsize = XSK_RING_CONS__DEFAULT_NUM_DESCS;
 		}
 	}
@@ -950,7 +952,10 @@ static void tx_stats_validate(struct ifobject *ifobject)
 
 static void thread_common_ops(struct test_spec *test, struct ifobject *ifobject)
 {
+	u64 umem_sz = ifobject->umem->num_frames * ifobject->umem->frame_size;
 	int mmap_flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE;
+	int ret, ifindex;
+	void *bufs;
 	u32 i;
 
 	ifobject->ns_fd = switch_namespace(ifobject->nsname);
@@ -958,23 +963,20 @@ static void thread_common_ops(struct test_spec *test, struct ifobject *ifobject)
 	if (ifobject->umem->unaligned_mode)
 		mmap_flags |= MAP_HUGETLB;
 
-	for (i = 0; i < test->nb_sockets; i++) {
-		u64 umem_sz = ifobject->umem->num_frames * ifobject->umem->frame_size;
-		u32 ctr = 0;
-		void *bufs;
-		int ret;
-
 	bufs = mmap(NULL, umem_sz, PROT_READ | PROT_WRITE, mmap_flags, -1, 0);
 	if (bufs == MAP_FAILED)
 		exit_with_error(errno);
 
-		ret = xsk_configure_umem(&ifobject->umem_arr[i], bufs, umem_sz);
+	ret = xsk_configure_umem(ifobject->umem, bufs, umem_sz);
 	if (ret)
 		exit_with_error(-ret);
 
+	for (i = 0; i < test->nb_sockets; i++) {
+		u32 ctr = 0;
+
 		while (ctr++ < SOCK_RECONF_CTR) {
-			ret = xsk_configure_socket(&ifobject->xsk_arr[i], &ifobject->umem_arr[i],
-						   ifobject, i);
+			ret = xsk_configure_socket(&ifobject->xsk_arr[i], ifobject->umem,
+						   ifobject, !!i);
 			if (!ret)
 				break;
 
@@ -985,8 +987,22 @@ static void thread_common_ops(struct test_spec *test, struct ifobject *ifobject)
 		}
 	}
 
-	ifobject->umem = &ifobject->umem_arr[0];
 	ifobject->xsk = &ifobject->xsk_arr[0];
+
+	if (!ifobject->rx_on)
+		return;
+
+	ifindex = if_nametoindex(ifobject->ifname);
+	if (!ifindex)
+		exit_with_error(errno);
+
+	ret = xsk_setup_xdp_prog(ifindex, &ifobject->xsk_map_fd);
+	if (ret)
+		exit_with_error(-ret);
+
+	ret = xsk_socket__update_xskmap(ifobject->xsk->xsk, ifobject->xsk_map_fd);
+	if (ret)
+		exit_with_error(-ret);
 }
 
 static void testapp_cleanup_xsk_res(struct ifobject *ifobj)
@@ -1142,14 +1158,16 @@ static void testapp_bidi(struct test_spec *test)
 
 static void swap_xsk_resources(struct ifobject *ifobj_tx, struct ifobject *ifobj_rx)
 {
+	int ret;
+
 	xsk_socket__delete(ifobj_tx->xsk->xsk);
-	xsk_umem__delete(ifobj_tx->umem->umem);
 	xsk_socket__delete(ifobj_rx->xsk->xsk);
-	xsk_umem__delete(ifobj_rx->umem->umem);
-	ifobj_tx->umem = &ifobj_tx->umem_arr[1];
 	ifobj_tx->xsk = &ifobj_tx->xsk_arr[1];
-	ifobj_rx->umem = &ifobj_rx->umem_arr[1];
 	ifobj_rx->xsk = &ifobj_rx->xsk_arr[1];
+
+	ret = xsk_socket__update_xskmap(ifobj_rx->xsk->xsk, ifobj_rx->xsk_map_fd);
+	if (ret)
+		exit_with_error(-ret);
 }
 
 static void testapp_bpf_res(struct test_spec *test)
@@ -1408,13 +1426,13 @@ static struct ifobject *ifobject_create(void)
 	if (!ifobj->xsk_arr)
 		goto out_xsk_arr;
 
-	ifobj->umem_arr = calloc(MAX_SOCKETS, sizeof(*ifobj->umem_arr));
-	if (!ifobj->umem_arr)
-		goto out_umem_arr;
+	ifobj->umem = calloc(1, sizeof(*ifobj->umem));
+	if (!ifobj->umem)
+		goto out_umem;
 
 	return ifobj;
 
-out_umem_arr:
+out_umem:
 	free(ifobj->xsk_arr);
 out_xsk_arr:
 	free(ifobj);
@@ -1423,7 +1441,7 @@ static struct ifobject *ifobject_create(void)
 
 static void ifobject_delete(struct ifobject *ifobj)
 {
-	free(ifobj->umem_arr);
+	free(ifobj->umem);
 	free(ifobj->xsk_arr);
 	free(ifobj);
 }

tools/testing/selftests/bpf/xdpxceiver.h

@@ -125,10 +125,10 @@ struct ifobject {
 	struct xsk_socket_info *xsk;
 	struct xsk_socket_info *xsk_arr;
 	struct xsk_umem_info *umem;
-	struct xsk_umem_info *umem_arr;
 	thread_func_t func_ptr;
 	struct pkt_stream *pkt_stream;
 	int ns_fd;
+	int xsk_map_fd;
 	u32 dst_ip;
 	u32 src_ip;
 	u32 xdp_flags;