selftests: drv-net: gro: add test for packet ordering

Add a test to check if the NIC reorders packets if the hit GRO.

Link: https://patch.msgid.link/20260318033819.1469350-6-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 35 insertions, 3 deletions

diff --git a/tools/testing/selftests/net/lib/gro.c b/tools/testing/selftests/net/lib/gro.c
index 41794b9f6f8a..3e611ae25f61 100644
--- a/tools/testing/selftests/net/lib/gro.c
+++ b/tools/testing/selftests/net/lib/gro.c
@@ -131,6 +131,7 @@ static int ethhdr_proto = -1;
 static bool ipip;
 static uint64_t txtime_ns;
 static int num_flows = 4;
+static bool order_check;
 
 #define CAPACITY_PAYLOAD_LEN 200
 
@@ -1136,6 +1137,7 @@ static void check_capacity_pkts(int fd)
 	static char buffer[IP_MAXPACKET + ETH_HLEN + 1];
 	struct iphdr *iph = (struct iphdr *)(buffer + ETH_HLEN);
 	struct ipv6hdr *ip6h = (struct ipv6hdr *)(buffer + ETH_HLEN);
+	int num_pkt = 0, num_coal = 0, pkt_idx;
 	const char *fail_reason = NULL;
 	int flow_order[num_flows * 2];
 	int coalesced[num_flows];
@@ -1144,8 +1146,6 @@ static void check_capacity_pkts(int fd)
 	int total_data = 0;
 	int pkt_size = -1;
 	int data_len = 0;
-	int num_pkt = 0;
-	int num_coal = 0;
 	int flow_id;
 	int sport;
 
@@ -1203,6 +1203,34 @@ static void check_capacity_pkts(int fd)
 		total_data += data_len;
 	}
 
+	/* Check flow ordering. We expect to see all non-coalesced first segs
+	 * then interleaved coalesced and non-coalesced second frames.
+	 */
+	pkt_idx = 0;
+	for (flow_id = 0; order_check && flow_id < num_flows; flow_id++) {
+		bool coaled = coalesced[flow_id] > CAPACITY_PAYLOAD_LEN;
+
+		if (coaled)
+			continue;
+
+		if (flow_order[pkt_idx] != flow_id) {
+			vlog("Flow order mismatch (non-coalesced) at position %d: expected flow %d, got flow %d\n",
+			     pkt_idx, flow_id, flow_order[pkt_idx]);
+			fail_reason = fail_reason ?: "bad packet order (1)";
+		}
+		pkt_idx++;
+	}
+	for (flow_id = 0; order_check && flow_id < num_flows; flow_id++) {
+		bool coaled = coalesced[flow_id] > CAPACITY_PAYLOAD_LEN;
+
+		if (flow_order[pkt_idx] != flow_id) {
+			vlog("Flow order mismatch at position %d: expected flow %d, got flow %d, coalesced: %d\n",
+			     pkt_idx, flow_id, flow_order[pkt_idx], coaled);
+			fail_reason = fail_reason ?: "bad packet order (2)";
+		}
+		pkt_idx++;
+	}
+
 	if (!fail_reason) {
 		vlog("All %d flows coalesced correctly\n", num_flows);
 		printf("Test succeeded\n\n");
@@ -1622,12 +1650,13 @@ static void parse_args(int argc, char **argv)
 		{ "saddr", required_argument, NULL, 's' },
 		{ "smac", required_argument, NULL, 'S' },
 		{ "test", required_argument, NULL, 't' },
+		{ "order-check", no_argument, NULL, 'o' },
 		{ "verbose", no_argument, NULL, 'v' },
 		{ 0, 0, 0, 0 }
 	};
 	int c;
 
-	while ((c = getopt_long(argc, argv, "46d:D:ei:n:rs:S:t:v", opts, NULL)) != -1) {
+	while ((c = getopt_long(argc, argv, "46d:D:ei:n:rs:S:t:ov", opts, NULL)) != -1) {
 		switch (c) {
 		case '4':
 			proto = PF_INET;
@@ -1666,6 +1695,9 @@ static void parse_args(int argc, char **argv)
 		case 't':
 			testname = optarg;
 			break;
+		case 'o':
+			order_check = true;
+			break;
 		case 'v':
 			verbose = true;
 			break;