selftests/xsk: dump packet at error

Dump the content of the packet when a test finds that packets are
received out of order, the length is wrong, or some other packet
error. Use the already existing pkt_dump function for this and call it
when the above errors are detected. Get rid of the command line option
for dumping packets as it is not useful to print out thousands of
good packets followed by the faulty one you would like to see.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20230516103109.3066-5-magnus.karlsson@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/test_xsk.sh

@@ -68,9 +68,6 @@
 # Run with verbose output:
 #   sudo ./test_xsk.sh -v
 #
-# Run and dump packet contents:
-#   sudo ./test_xsk.sh -D
-#
 # Set up veth interfaces and leave them up so xskxceiver can be launched in a debugger:
 #   sudo ./test_xsk.sh -d
 #
@@ -81,11 +78,10 @@
 
 ETH=""
 
-while getopts "vDi:d" flag
+while getopts "vi:d" flag
 do
 	case "${flag}" in
 		v) verbose=1;;
-		D) dump_pkts=1;;
 		d) debug=1;;
 		i) ETH=${OPTARG};;
 	esac
@@ -157,10 +153,6 @@ if [[ $verbose -eq 1 ]]; then
 	ARGS+="-v "
 fi
 
-if [[ $dump_pkts -eq 1 ]]; then
-	ARGS="-D "
-fi
-
 retval=$?
 test_status $retval "${TEST_NAME}"
 

tools/testing/selftests/bpf/xskxceiver.c

@@ -275,7 +275,6 @@ static bool ifobj_zc_avail(struct ifobject *ifobject)
 static struct option long_options[] = {
 	{"interface", required_argument, 0, 'i'},
 	{"busy-poll", no_argument, 0, 'b'},
-	{"dump-pkts", no_argument, 0, 'D'},
 	{"verbose", no_argument, 0, 'v'},
 	{0, 0, 0, 0}
 };
@@ -286,7 +285,6 @@ static void usage(const char *prog)
 		"  Usage: %s [OPTIONS]\n"
 		"  Options:\n"
 		"  -i, --interface      Use interface\n"
-		"  -D, --dump-pkts      Dump packets L2 - L5\n"
 		"  -v, --verbose        Verbose output\n"
 		"  -b, --busy-poll      Enable busy poll\n";
 
@@ -310,7 +308,7 @@ static void parse_command_line(struct ifobject *ifobj_tx, struct ifobject *ifobj
 	opterr = 0;
 
 	for (;;) {
-		c = getopt_long(argc, argv, "i:Dvb", long_options, &option_index);
+		c = getopt_long(argc, argv, "i:vb", long_options, &option_index);
 		if (c == -1)
 			break;
 
@@ -332,9 +330,6 @@ static void parse_command_line(struct ifobject *ifobj_tx, struct ifobject *ifobj
 
 			interface_nb++;
 			break;
-		case 'D':
-			opt_pkt_dump = true;
-			break;
 		case 'v':
 			opt_verbose = true;
 			break;
@@ -714,7 +709,7 @@ static bool is_pkt_valid(struct pkt *pkt, void *buffer, u64 addr, u32 len)
 
 	if (!pkt) {
 		ksft_print_msg("[%s] too many packets received\n", __func__);
-		return false;
+		goto error;
 	}
 
 	if (len < MIN_PKT_SIZE || pkt->len < MIN_PKT_SIZE) {
@@ -725,22 +720,23 @@ static bool is_pkt_valid(struct pkt *pkt, void *buffer, u64 addr, u32 len)
 	if (pkt->len != len) {
 		ksft_print_msg("[%s] expected length [%d], got length [%d]\n",
 			       __func__, pkt->len, len);
-		return false;
+		goto error;
 	}
 
 	pkt_data = ntohl(*((u32 *)(data + PKT_HDR_SIZE)));
 	seqnum = pkt_data >> 16;
 
-	if (opt_pkt_dump)
-		pkt_dump(data, len);
-
 	if (pkt->pkt_nb != seqnum) {
 		ksft_print_msg("[%s] expected seqnum [%d], got seqnum [%d]\n",
 			       __func__, pkt->pkt_nb, seqnum);
-		return false;
+		goto error;
 	}
 
 	return true;
+
+error:
+	pkt_dump(data, len);
+	return false;
 }
 
 static void kick_tx(struct xsk_socket_info *xsk)

tools/testing/selftests/bpf/xskxceiver.h

@@ -85,7 +85,6 @@ enum test_type {
 	TEST_TYPE_MAX
 };
 
-static bool opt_pkt_dump;
 static bool opt_verbose;
 
 struct xsk_umem_info {