[PATCH linux-next 1/3] selftests: net: udpgso_bench_rx: Fix verifty exceptions

[Yang Yang <yang.yang29@zte.com.cn>]

From: Zhang Yunkai (CGEL ZTE) <zhang.yunkai@zte.com.cn>

The verification function of this test case is likely to encounter the
following error, which may confuse users.

Executing the following command fails:
bash# udpgso_bench_tx -l 4 -4 -D "$DST"
bash# udpgso_bench_tx -l 4 -4 -D "$DST" -S 0
bash# udpgso_bench_rx -4 -G -S 1472 -v
udpgso_bench_rx: data[1472]: len 2944, a(97) != q(113)

This is because the sending buffers are not aligned by 26 bytes, and the
GRO is not merged sequentially, and the receiver does not judge this
situation. We do the validation after the data is split at the receiving
end, just as the application actually uses this feature.

Signed-off-by: Zhang Yunkai (CGEL ZTE) <zhang.yunkai@zte.com.cn>
Reviewed-by: xu xin (CGEL ZTE) <xu.xin16@zte.com.cn>
Reviewed-by: Yang Yang (CGEL ZTE) <yang.yang29@zte.com.cn>
Cc: Xuexin Jiang (CGEL ZTE) <jiang.xuexin@zte.com.cn>
---
 tools/testing/selftests/net/udpgso_bench_rx.c | 38 +++++++++++++++++++++------
 1 file changed, 30 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/net/udpgso_bench_rx.c b/tools/testing/selftests/net/udpgso_bench_rx.c
index f35a924d4a30..a5b7f30659a5 100644
--- a/tools/testing/selftests/net/udpgso_bench_rx.c
+++ b/tools/testing/selftests/net/udpgso_bench_rx.c
@@ -189,16 +189,16 @@ static char sanitized_char(char val)
 	return (val >= 'a' && val <= 'z') ? val : '.';
 }
 
-static void do_verify_udp(const char *data, int len)
+static void do_verify_udp(const char *data, int start, int len)
 {
-	char cur = data[0];
+	char cur = data[start];
 	int i;
 
 	/* verify contents */
 	if (cur < 'a' || cur > 'z')
 		error(1, 0, "data initial byte out of range");
 
-	for (i = 1; i < len; i++) {
+	for (i = start + 1; i < start + len; i++) {
 		if (cur == 'z')
 			cur = 'a';
 		else
@@ -212,6 +212,24 @@ static void do_verify_udp(const char *data, int len)
 	}
 }
 
+static void do_verify_udp_gro(const char *data, int len, int gso_size)
+{
+	int remaining = len;
+	int start = 0;
+
+	while (remaining) {
+		if (remaining < 0)
+			break;
+
+		if (remaining > gso_size)
+			do_verify_udp(data, start, gso_size);
+		else
+			do_verify_udp(data, start, remaining);
+		start += gso_size;
+		remaining -= gso_size;
+	}
+}
+
 static int recv_msg(int fd, char *buf, int len, int *gso_size)
 {
 	char control[CMSG_SPACE(sizeof(int))] = {0};
@@ -264,16 +282,20 @@ static void do_flush_udp(int fd)
 		if (cfg_expected_pkt_len && ret != cfg_expected_pkt_len)
 			error(1, 0, "recv: bad packet len, got %d,"
 			      " expected %d\n", ret, cfg_expected_pkt_len);
+		if (cfg_expected_gso_size && cfg_expected_gso_size != gso_size)
+			error(1, 0, "recv: bad gso size, got %d, expected %d %s",
+				gso_size, cfg_expected_gso_size, "(-1 == no gso cmsg))\n");
 		if (len && cfg_verify) {
 			if (ret == 0)
 				error(1, errno, "recv: 0 byte datagram\n");
 
-			do_verify_udp(rbuf, ret);
+			if (!cfg_gro_segment)
+				do_verify_udp(rbuf, 0, ret);
+			else if (gso_size > 0)
+				do_verify_udp_gro(rbuf, ret, gso_size);
+			else
+				do_verify_udp_gro(rbuf, ret, ret);
 		}
-		if (cfg_expected_gso_size && cfg_expected_gso_size != gso_size)
-			error(1, 0, "recv: bad gso size, got %d, expected %d "
-			      "(-1 == no gso cmsg))\n", gso_size,
-			      cfg_expected_gso_size);
 
 		packets++;
 		bytes += ret;
-- 
2.15.2