1 files changed, 278 insertions, 0 deletions
diff --git a/net/core/gso_test.c b/net/core/gso_test.c
new file mode 100644
index 000000000000..ceb684be4cbf
--- /dev/null
+++ b/net/core/gso_test.c
@@ -0,0 +1,278 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <kunit/test.h>
+#include <linux/skbuff.h>
+
+static const char hdr[] = "abcdefgh";
+#define GSO_TEST_SIZE 1000
+
+static void __init_skb(struct sk_buff *skb)
+{
+	skb_reset_mac_header(skb);
+	memcpy(skb_mac_header(skb), hdr, sizeof(hdr));
+
+	/* skb_segment expects skb->data at start of payload */
+	skb_pull(skb, sizeof(hdr));
+	skb_reset_network_header(skb);
+	skb_reset_transport_header(skb);
+
+	/* proto is arbitrary, as long as not ETH_P_TEB or vlan */
+	skb->protocol = htons(ETH_P_ATALK);
+	skb_shinfo(skb)->gso_size = GSO_TEST_SIZE;
+}
+
+enum gso_test_nr {
+	GSO_TEST_LINEAR,
+	GSO_TEST_NO_GSO,
+	GSO_TEST_FRAGS,
+	GSO_TEST_FRAGS_PURE,
+	GSO_TEST_GSO_PARTIAL,
+	GSO_TEST_FRAG_LIST,
+	GSO_TEST_FRAG_LIST_PURE,
+	GSO_TEST_FRAG_LIST_NON_UNIFORM,
+	GSO_TEST_GSO_BY_FRAGS,
+};
+
+struct gso_test_case {
+	enum gso_test_nr id;
+	const char *name;
+
+	/* input */
+	unsigned int linear_len;
+	unsigned int nr_frags;
+	const unsigned int *frags;
+	unsigned int nr_frag_skbs;
+	const unsigned int *frag_skbs;
+
+	/* output as expected */
+	unsigned int nr_segs;
+	const unsigned int *segs;
+};
+
+static struct gso_test_case cases[] = {
+	{
+		.id = GSO_TEST_NO_GSO,
+		.name = "no_gso",
+		.linear_len = GSO_TEST_SIZE,
+		.nr_segs = 1,
+		.segs = (const unsigned int[]) { GSO_TEST_SIZE },
+	},
+	{
+		.id = GSO_TEST_LINEAR,
+		.name = "linear",
+		.linear_len = GSO_TEST_SIZE + GSO_TEST_SIZE + 1,
+		.nr_segs = 3,
+		.segs = (const unsigned int[]) { GSO_TEST_SIZE, GSO_TEST_SIZE, 1 },
+	},
+	{
+		.id = GSO_TEST_FRAGS,
+		.name = "frags",
+		.linear_len = GSO_TEST_SIZE,
+		.nr_frags = 2,
+		.frags = (const unsigned int[]) { GSO_TEST_SIZE, 1 },
+		.nr_segs = 3,
+		.segs = (const unsigned int[]) { GSO_TEST_SIZE, GSO_TEST_SIZE, 1 },
+	},
+	{
+		.id = GSO_TEST_FRAGS_PURE,
+		.name = "frags_pure",
+		.nr_frags = 3,
+		.frags = (const unsigned int[]) { GSO_TEST_SIZE, GSO_TEST_SIZE, 2 },
+		.nr_segs = 3,
+		.segs = (const unsigned int[]) { GSO_TEST_SIZE, GSO_TEST_SIZE, 2 },
+	},
+	{
+		.id = GSO_TEST_GSO_PARTIAL,
+		.name = "gso_partial",
+		.linear_len = GSO_TEST_SIZE,
+		.nr_frags = 2,
+		.frags = (const unsigned int[]) { GSO_TEST_SIZE, 3 },
+		.nr_segs = 2,
+		.segs = (const unsigned int[]) { 2 * GSO_TEST_SIZE, 3 },
+	},
+	{
+		/* commit 89319d3801d1: frag_list on mss boundaries */
+		.id = GSO_TEST_FRAG_LIST,
+		.name = "frag_list",
+		.linear_len = GSO_TEST_SIZE,
+		.nr_frag_skbs = 2,
+		.frag_skbs = (const unsigned int[]) { GSO_TEST_SIZE, GSO_TEST_SIZE },
+		.nr_segs = 3,
+		.segs = (const unsigned int[]) { GSO_TEST_SIZE, GSO_TEST_SIZE, GSO_TEST_SIZE },
+	},
+	{
+		.id = GSO_TEST_FRAG_LIST_PURE,
+		.name = "frag_list_pure",
+		.nr_frag_skbs = 2,
+		.frag_skbs = (const unsigned int[]) { GSO_TEST_SIZE, GSO_TEST_SIZE },
+		.nr_segs = 2,
+		.segs = (const unsigned int[]) { GSO_TEST_SIZE, GSO_TEST_SIZE },
+	},
+	{
+		/* commit 43170c4e0ba7: GRO of frag_list trains */
+		.id = GSO_TEST_FRAG_LIST_NON_UNIFORM,
+		.name = "frag_list_non_uniform",
+		.linear_len = GSO_TEST_SIZE,
+		.nr_frag_skbs = 4,
+		.frag_skbs = (const unsigned int[]) { GSO_TEST_SIZE, 1, GSO_TEST_SIZE, 2 },
+		.nr_segs = 4,
+		.segs = (const unsigned int[]) { GSO_TEST_SIZE, GSO_TEST_SIZE, GSO_TEST_SIZE, 3 },
+	},
+	{
+		/* commit 3953c46c3ac7 ("sk_buff: allow segmenting based on frag sizes") and
+		 * commit 90017accff61 ("sctp: Add GSO support")
+		 *
+		 * "there will be a cover skb with protocol headers and
+		 *  children ones containing the actual segments"
+		 */
+		.id = GSO_TEST_GSO_BY_FRAGS,
+		.name = "gso_by_frags",
+		.nr_frag_skbs = 4,
+		.frag_skbs = (const unsigned int[]) { 100, 200, 300, 400 },
+		.nr_segs = 4,
+		.segs = (const unsigned int[]) { 100, 200, 300, 400 },
+	},
+};
+
+static void gso_test_case_to_desc(struct gso_test_case *t, char *desc)
+{
+	sprintf(desc, "%s", t->name);
+}
+
+KUNIT_ARRAY_PARAM(gso_test, cases, gso_test_case_to_desc);
+
+static void gso_test_func(struct kunit *test)
+{
+	const int shinfo_size = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
+	struct sk_buff *skb, *segs, *cur, *next, *last;
+	const struct gso_test_case *tcase;
+	netdev_features_t features;
+	struct page *page;
+	int i;
+
+	tcase = test->param_value;
+
+	page = alloc_page(GFP_KERNEL);
+	KUNIT_ASSERT_NOT_NULL(test, page);
+	skb = build_skb(page_address(page), sizeof(hdr) + tcase->linear_len + shinfo_size);
+	KUNIT_ASSERT_NOT_NULL(test, skb);
+	__skb_put(skb, sizeof(hdr) + tcase->linear_len);
+
+	__init_skb(skb);
+
+	if (tcase->nr_frags) {
+		unsigned int pg_off = 0;
+
+		page = alloc_page(GFP_KERNEL);
+		KUNIT_ASSERT_NOT_NULL(test, page);
+		page_ref_add(page, tcase->nr_frags - 1);
+
+		for (i = 0; i < tcase->nr_frags; i++) {
+			skb_fill_page_desc(skb, i, page, pg_off, tcase->frags[i]);
+			pg_off += tcase->frags[i];
+		}
+
+		KUNIT_ASSERT_LE(test, pg_off, PAGE_SIZE);
+
+		skb->data_len = pg_off;
+		skb->len += skb->data_len;
+		skb->truesize += skb->data_len;
+	}
+
+	if (tcase->frag_skbs) {
+		unsigned int total_size = 0, total_true_size = 0, alloc_size = 0;
+		struct sk_buff *frag_skb, *prev = NULL;
+
+		page = alloc_page(GFP_KERNEL);
+		KUNIT_ASSERT_NOT_NULL(test, page);
+		page_ref_add(page, tcase->nr_frag_skbs - 1);
+
+		for (i = 0; i < tcase->nr_frag_skbs; i++) {
+			unsigned int frag_size;
+
+			frag_size = tcase->frag_skbs[i];
+			frag_skb = build_skb(page_address(page) + alloc_size,
+					     frag_size + shinfo_size);
+			KUNIT_ASSERT_NOT_NULL(test, frag_skb);
+			__skb_put(frag_skb, frag_size);
+
+			if (prev)
+				prev->next = frag_skb;
+			else
+				skb_shinfo(skb)->frag_list = frag_skb;
+			prev = frag_skb;
+
+			total_size += frag_size;
+			total_true_size += frag_skb->truesize;
+			alloc_size += frag_size + shinfo_size;
+		}
+
+		KUNIT_ASSERT_LE(test, alloc_size, PAGE_SIZE);
+
+		skb->len += total_size;
+		skb->data_len += total_size;
+		skb->truesize += total_true_size;
+
+		if (tcase->id == GSO_TEST_GSO_BY_FRAGS)
+			skb_shinfo(skb)->gso_size = GSO_BY_FRAGS;
+	}
+
+	features = NETIF_F_SG | NETIF_F_HW_CSUM;
+	if (tcase->id == GSO_TEST_GSO_PARTIAL)
+		features |= NETIF_F_GSO_PARTIAL;
+
+	/* TODO: this should also work with SG,
+	 * rather than hit BUG_ON(i >= nfrags)
+	 */
+	if (tcase->id == GSO_TEST_FRAG_LIST_NON_UNIFORM)
+		features &= ~NETIF_F_SG;
+
+	segs = skb_segment(skb, features);
+	if (IS_ERR(segs)) {
+		KUNIT_FAIL(test, "segs error %lld", PTR_ERR(segs));
+		goto free_gso_skb;
+	} else if (!segs) {
+		KUNIT_FAIL(test, "no segments");
+		goto free_gso_skb;
+	}
+
+	last = segs->prev;
+	for (cur = segs, i = 0; cur; cur = next, i++) {
+		next = cur->next;
+
+		KUNIT_ASSERT_EQ(test, cur->len, sizeof(hdr) + tcase->segs[i]);
+
+		/* segs have skb->data pointing to the mac header */
+		KUNIT_ASSERT_PTR_EQ(test, skb_mac_header(cur), cur->data);
+		KUNIT_ASSERT_PTR_EQ(test, skb_network_header(cur), cur->data + sizeof(hdr));
+
+		/* header was copied to all segs */
+		KUNIT_ASSERT_EQ(test, memcmp(skb_mac_header(cur), hdr, sizeof(hdr)), 0);
+
+		/* last seg can be found through segs->prev pointer */
+		if (!next)
+			KUNIT_ASSERT_PTR_EQ(test, cur, last);
+
+		consume_skb(cur);
+	}
+
+	KUNIT_ASSERT_EQ(test, i, tcase->nr_segs);
+
+free_gso_skb:
+	consume_skb(skb);
+}
+
+static struct kunit_case gso_test_cases[] = {
+	KUNIT_CASE_PARAM(gso_test_func, gso_test_gen_params),
+	{}
+};
+
+static struct kunit_suite gso_test_suite = {
+	.name = "net_core_gso",
+	.test_cases = gso_test_cases,
+};
+
+kunit_test_suite(gso_test_suite);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("KUnit tests for segmentation offload");