selftests/net: udpgso: test small gso_size boundary conditions

Verify that udpgso can generate segments smaller than device mtu, down
to the extreme case of 1B gso_size.

Verify that irrespective of gso_size, udpgso restricts the number of
segments it will generate per call (UDP_MAX_SEGMENTS).

Signed-off-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/tools/testing/selftests/net/udpgso.c b/tools/testing/selftests/net/udpgso.c
index 48a0592db938f3897e23a2e81fa260118f3064d4..e279051bc6312c132999e00a13b37c2555e6b2cb 100644 (file)
--- a/tools/testing/selftests/net/udpgso.c
+++ b/tools/testing/selftests/net/udpgso.c
@@ -34,6 +34,10 @@
 #define UDP_SEGMENT            103
 #endif
 
+#ifndef UDP_MAX_SEGMENTS
+#define UDP_MAX_SEGMENTS       (1 << 6UL)
+#endif
+
 #define CONST_MTU_TEST 1500
 
 #define CONST_HDRLEN_V4                (sizeof(struct iphdr) + sizeof(struct udphdr))
@@ -135,6 +139,38 @@ struct testcase testcases_v4[] = {
                .gso_len = CONST_MSS_V4,
                .tfail = true,
        },
+       {
+               /* send a single 1B MSS: will fail, see single MSS above */
+               .tlen = 1,
+               .gso_len = 1,
+               .tfail = true,
+               .r_num_mss = 1,
+       },
+       {
+               /* send 2 1B segments */
+               .tlen = 2,
+               .gso_len = 1,
+               .r_num_mss = 2,
+       },
+       {
+               /* send 2B + 2B + 1B segments */
+               .tlen = 5,
+               .gso_len = 2,
+               .r_num_mss = 2,
+               .r_len_last = 1,
+       },
+       {
+               /* send max number of min sized segments */
+               .tlen = UDP_MAX_SEGMENTS - CONST_HDRLEN_V4,
+               .gso_len = 1,
+               .r_num_mss = UDP_MAX_SEGMENTS - CONST_HDRLEN_V4,
+       },
+       {
+               /* send max number + 1 of min sized segments: fail */
+               .tlen = UDP_MAX_SEGMENTS - CONST_HDRLEN_V4 + 1,
+               .gso_len = 1,
+               .tfail = true,
+       },
        {
                /* EOL */
        }
@@ -210,6 +246,38 @@ struct testcase testcases_v6[] = {
                .gso_len = CONST_MSS_V6,
                .tfail = true,
        },
+       {
+               /* send a single 1B MSS: will fail, see single MSS above */
+               .tlen = 1,
+               .gso_len = 1,
+               .tfail = true,
+               .r_num_mss = 1,
+       },
+       {
+               /* send 2 1B segments */
+               .tlen = 2,
+               .gso_len = 1,
+               .r_num_mss = 2,
+       },
+       {
+               /* send 2B + 2B + 1B segments */
+               .tlen = 5,
+               .gso_len = 2,
+               .r_num_mss = 2,
+               .r_len_last = 1,
+       },
+       {
+               /* send max number of min sized segments */
+               .tlen = UDP_MAX_SEGMENTS - CONST_HDRLEN_V6,
+               .gso_len = 1,
+               .r_num_mss = UDP_MAX_SEGMENTS - CONST_HDRLEN_V6,
+       },
+       {
+               /* send max number + 1 of min sized segments: fail */
+               .tlen = UDP_MAX_SEGMENTS - CONST_HDRLEN_V6 + 1,
+               .gso_len = 1,
+               .tfail = true,
+       },
        {
                /* EOL */
        }
@@ -375,7 +443,8 @@ static bool __send_one(int fd, struct msghdr *msg, int flags)
        int ret;
 
        ret = sendmsg(fd, msg, flags);
-       if (ret == -1 && (errno == EMSGSIZE || errno == ENOMEM))
+       if (ret == -1 &&
+           (errno == EMSGSIZE || errno == ENOMEM || errno == EINVAL))
                return false;
        if (ret == -1)
                error(1, errno, "sendmsg");
@@ -466,7 +535,11 @@ static void run_one(struct testcase *test, int fdt, int fdr,
        if (!sent)
                return;
 
-       mss = addr->sa_family == AF_INET ? CONST_MSS_V4 : CONST_MSS_V6;
+       if (test->gso_len)
+               mss = test->gso_len;
+       else
+               mss = addr->sa_family == AF_INET ? CONST_MSS_V4 : CONST_MSS_V6;
+
 
        /* Recv all full MSS datagrams */
        for (i = 0; i < test->r_num_mss; i++) {