[PATCH v21 bpf-next 17/23] bpf: selftests: update xdp_adjust_tail selftest to include multi-buffer

@@ -130,6 +130,133 @@ static void test_xdp_adjust_tail_grow2(void)
 	bpf_object__close(obj);
 }
 
+void test_xdp_adjust_mb_tail_shrink(void)
+{
+	const char *file = "./test_xdp_adjust_tail_shrink.o";
+	__u32 duration, retval, size, exp_size;
+	struct bpf_program *prog;
+	struct bpf_object *obj;
+	int err, prog_fd;
+	__u8 *buf;
+
+	/* For the individual test cases, the first byte in the packet
+	 * indicates which test will be run.
+	 */
+	obj = bpf_object__open(file);
+	if (libbpf_get_error(obj))
+		return;
+
+	prog = bpf_object__next_program(obj, NULL);
+	if (bpf_object__load(obj))
+		return;
+
+	prog_fd = bpf_program__fd(prog);
+
+	buf = malloc(9000);
+	if (CHECK(!buf, "malloc()", "error:%s\n", strerror(errno)))
+		goto out;
+
+	memset(buf, 0, 9000);
+
+	/* Test case removing 10 bytes from last frag, NOT freeing it */
+	exp_size = 8990; /* 9000 - 10 */
+	err = bpf_prog_test_run(prog_fd, 1, buf, 9000,
+				buf, &size, &retval, &duration);
+
+	CHECK(err || retval != XDP_TX || size != exp_size,
+	      "9k-10b", "err %d errno %d retval %d[%d] size %d[%u]\n",
+	      err, errno, retval, XDP_TX, size, exp_size);
+
+	/* Test case removing one of two pages, assuming 4K pages */
+	buf[0] = 1;
+	exp_size = 4900; /* 9000 - 4100 */
+	err = bpf_prog_test_run(prog_fd, 1, buf, 9000,
+				buf, &size, &retval, &duration);
+
+	CHECK(err || retval != XDP_TX || size != exp_size,
+	      "9k-1p", "err %d errno %d retval %d[%d] size %d[%u]\n",
+	      err, errno, retval, XDP_TX, size, exp_size);
+
+	/* Test case removing two pages resulting in a non mb xdp_buff */
+	buf[0] = 2;
+	exp_size = 800; /* 9000 - 8200 */
+	err = bpf_prog_test_run(prog_fd, 1, buf, 9000,
+				buf, &size, &retval, &duration);
+
+	CHECK(err || retval != XDP_TX || size != exp_size,
+	      "9k-2p", "err %d errno %d retval %d[%d] size %d[%u]\n",
+	      err, errno, retval, XDP_TX, size, exp_size);
+
+	free(buf);
+out:
+	bpf_object__close(obj);
+}
+
+void test_xdp_adjust_mb_tail_grow(void)
+{
+	const char *file = "./test_xdp_adjust_tail_grow.o";
+	__u32 duration, retval, size, exp_size;
+	struct bpf_program *prog;
+	struct bpf_object *obj;
+	int err, i, prog_fd;
+	__u8 *buf;
+
+	obj = bpf_object__open(file);
+	if (libbpf_get_error(obj))
+		return;
+
+	prog = bpf_object__next_program(obj, NULL);
+	if (bpf_object__load(obj))
+		return;
+
+	prog_fd = bpf_program__fd(prog);
+
+	buf = malloc(16384);
+	if (CHECK(!buf, "malloc()", "error:%s\n", strerror(errno)))
+		goto out;
+
+	/* Test case add 10 bytes to last frag */
+	memset(buf, 1, 16384);
+	size = 9000;
+	exp_size = size + 10;
+	err = bpf_prog_test_run(prog_fd, 1, buf, size,
+				buf, &size, &retval, &duration);
+
+	CHECK(err || retval != XDP_TX || size != exp_size,
+	      "9k+10b", "err %d retval %d[%d] size %d[%u]\n",
+	      err, retval, XDP_TX, size, exp_size);
+
+	for (i = 0; i < 9000; i++)
+		CHECK(buf[i] != 1, "9k+10b-old",
+		      "Old data not all ok, offset %i is failing [%u]!\n",
+		      i, buf[i]);
+
+	for (i = 9000; i < 9010; i++)
+		CHECK(buf[i] != 0, "9k+10b-new",
+		      "New data not all ok, offset %i is failing [%u]!\n",
+		      i, buf[i]);
+
+	for (i = 9010; i < 16384; i++)
+		CHECK(buf[i] != 1, "9k+10b-untouched",
+		      "Unused data not all ok, offset %i is failing [%u]!\n",
+		      i, buf[i]);
+
+	/* Test a too large grow */
+	memset(buf, 1, 16384);
+	size = 9001;
+	exp_size = size;
+	err = bpf_prog_test_run(prog_fd, 1, buf, size,
+				buf, &size, &retval, &duration);
+
+	CHECK(err || retval != XDP_DROP || size != exp_size,
+	      "9k+10b", "err %d retval %d[%d] size %d[%u]\n",
+	      err, retval, XDP_TX, size, exp_size);
+
+	free(buf);
+out:
+	bpf_object__close(obj);
+}
+
 void test_xdp_adjust_tail(void)
 {
 	if (test__start_subtest("xdp_adjust_tail_shrink"))

@@ -138,4 +265,8 @@ void test_xdp_adjust_tail(void)
 		test_xdp_adjust_tail_grow();
 	if (test__start_subtest("xdp_adjust_tail_grow2"))
 		test_xdp_adjust_tail_grow2();
+	if (test__start_subtest("xdp_adjust_mb_tail_shrink"))
+		test_xdp_adjust_mb_tail_shrink();
+	if (test__start_subtest("xdp_adjust_mb_tail_grow"))
+		test_xdp_adjust_mb_tail_grow();
 }

@@ -7,11 +7,10 @@ int _xdp_adjust_tail_grow(struct xdp_md *xdp)
 {
 	void *data_end = (void *)(long)xdp->data_end;
 	void *data = (void *)(long)xdp->data;
-	unsigned int data_len;
+	int data_len = bpf_xdp_get_buff_len(xdp);
 	int offset = 0;
 
 	/* Data length determine test case */
-	data_len = data_end - data;
 
 	if (data_len == 54) { /* sizeof(pkt_v4) */
 		offset = 4096; /* test too large offset */

@@ -20,7 +19,12 @@ int _xdp_adjust_tail_grow(struct xdp_md *xdp)
 	} else if (data_len == 64) {
 		offset = 128;
 	} else if (data_len == 128) {
-		offset = 4096 - 256 - 320 - data_len; /* Max tail grow 3520 */
+		/* Max tail grow 3520 */
+		offset = 4096 - 256 - 320 - data_len;
+	} else if (data_len == 9000) {
+		offset = 10;
+	} else if (data_len == 9001) {
+		offset = 4096;
 	} else {
 		return XDP_ABORTED; /* No matching test */
 	}

@@ -12,14 +12,38 @@
 SEC("xdp")
 int _xdp_adjust_tail_shrink(struct xdp_md *xdp)
 {
-	void *data_end = (void *)(long)xdp->data_end;
-	void *data = (void *)(long)xdp->data;
+	__u8 *data_end = (void *)(long)xdp->data_end;
+	__u8 *data = (void *)(long)xdp->data;
 	int offset = 0;
 
-	if (data_end - data == 54) /* sizeof(pkt_v4) */
+	switch (bpf_xdp_get_buff_len(xdp)) {
+	case 54:
+		/* sizeof(pkt_v4) */
 		offset = 256; /* shrink too much */
-	else
+		break;
+	case 9000:
+		/* Multi-buffer test cases */
+		if (data + 1 > data_end)
+			return XDP_DROP;
+
+		switch (data[0]) {
+		case 0:
+			offset = 10;
+			break;
+		case 1:
+			offset = 4100;
+			break;
+		case 2:
+			offset = 8200;
+			break;
+		default:
+			return XDP_DROP;
+		}
+		break;
+	default:
 		offset = 20;
+		break;
+	}
 	if (bpf_xdp_adjust_tail(xdp, 0 - offset))
 		return XDP_DROP;
 	return XDP_TX;