selftests: xsk: Implement bpf_link test

Introduce a test that is supposed to verify the persistence of BPF
resources based on underlying bpf_link usage.

Test will:
1) create and bind two sockets on queue ids 0 and 1
2) run a traffic on queue ids 0
3) remove xsk sockets from queue 0 on both veth interfaces
4) run a traffic on queues ids 1

Running traffic successfully on qids 1 means that BPF resources were
not removed on step 3).

In order to make it work, change the command that creates veth pair to
have the 4 queue pairs by default.

Introduce the arrays of xsks and umems to ifobject struct but keep a
pointers to single entities, so rest of the logic around Rx/Tx can be
kept as-is.

For umem handling, double the size of mmapped space and split that
between the two sockets.

Rename also bidi_pass to a variable 'second_step' of a boolean type as
it's now used also for the test that is introduced here and it doesn't
have anything in common with bi-directional testing.

Drop opt_queue command line argument as it wasn't working before anyway.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210329224316.17793-15-maciej.fijalkowski@intel.com

tools/testing/selftests/bpf/test_xsk.sh

@@ -107,7 +107,7 @@ setup_vethPairs() {
 	        echo "setting up ${VETH0}: namespace: ${NS0}"
 	fi
 	ip netns add ${NS1}
-	ip link add ${VETH0} type veth peer name ${VETH1}
+	ip link add ${VETH0} numtxqueues 4 numrxqueues 4 type veth peer name ${VETH1} numtxqueues 4 numrxqueues 4
 	if [ -f /proc/net/if_inet6 ]; then
 		echo 1 > /proc/sys/net/ipv6/conf/${VETH0}/disable_ipv6
 	fi
@@ -118,6 +118,7 @@ setup_vethPairs() {
 	ip netns exec ${NS1} ip link set ${VETH1} mtu ${MTU}
 	ip link set ${VETH0} mtu ${MTU}
 	ip netns exec ${NS1} ip link set ${VETH1} up
+	ip netns exec ${NS1} ip link set dev lo up
 	ip link set ${VETH0} up
 }
 

tools/testing/selftests/bpf/xdpxceiver.h

@@ -23,6 +23,7 @@
 #define MAX_SOCKS 1
 #define MAX_TEARDOWN_ITER 10
 #define MAX_BIDI_ITER 2
+#define MAX_BPF_ITER 2
 #define PKT_HDR_SIZE (sizeof(struct ethhdr) + sizeof(struct iphdr) + \
 			sizeof(struct udphdr))
 #define MIN_PKT_SIZE 64
@@ -63,6 +64,7 @@ enum TEST_TYPES {
 	TEST_TYPE_TEARDOWN,
 	TEST_TYPE_BIDI,
 	TEST_TYPE_STATS,
+	TEST_TYPE_BPF_RES,
 	TEST_TYPE_MAX
 };
 
@@ -77,10 +79,9 @@ enum STAT_TEST_TYPES {
 static int configured_mode = TEST_MODE_UNCONFIGURED;
 static u8 debug_pkt_dump;
 static u32 num_frames;
-static u8 bidi_pass;
+static bool second_step;
 static int test_type;
 
-static int opt_queue;
 static int opt_pkt_count;
 static u8 opt_verbose;
 
@@ -128,6 +129,8 @@ struct ifobject {
 	char ifname[MAX_INTERFACE_NAME_CHARS];
 	char nsname[MAX_INTERFACES_NAMESPACE_CHARS];
 	struct xsk_socket_info *xsk;
+	struct xsk_socket_info **xsk_arr;
+	struct xsk_umem_info **umem_arr;
 	struct xsk_umem_info *umem;
 	void *(*func_ptr)(void *arg);
 	struct flow_vector fv;