@@ -508,4 +508,13 @@ config NETDEV_ADDR_LIST_TEST
default KUNIT_ALL_TESTS
depends on KUNIT
+config NET_TEST
+ tristate "KUnit tests for networking" if !KUNIT_ALL_TESTS
+ depends on KUNIT
+ default KUNIT_ALL_TESTS
+ help
+ KUnit tests covering core networking infra, such as sk_buff.
+
+ If unsure, say N.
+
endif # if NET
@@ -40,3 +40,4 @@ obj-$(CONFIG_NET_SOCK_MSG) += skmsg.o
obj-$(CONFIG_BPF_SYSCALL) += sock_map.o
obj-$(CONFIG_BPF_SYSCALL) += bpf_sk_storage.o
obj-$(CONFIG_OF) += of_net.o
+obj-$(CONFIG_NET_TEST) += gso_test.o
new file mode 100644
@@ -0,0 +1,87 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <kunit/test.h>
+#include <linux/skbuff.h>
+
+static const char hdr[] = "abcdefgh";
+static const int gso_size = 1000, last_seg_size = 1;
+
+/* default: create 3 segment gso packet */
+static const int payload_len = (2 * gso_size) + last_seg_size;
+
+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_size;
+}
+
+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;
+ struct page *page;
+
+ page = alloc_page(GFP_KERNEL);
+ KUNIT_ASSERT_NOT_NULL(test, page);
+ skb = build_skb(page_address(page), sizeof(hdr) + payload_len + shinfo_size);
+ KUNIT_ASSERT_NOT_NULL(test, skb);
+ __skb_put(skb, sizeof(hdr) + payload_len);
+
+ __init_skb(skb);
+
+ segs = skb_segment(skb, NETIF_F_SG | NETIF_F_HW_CSUM);
+ 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;
+ }
+
+ for (cur = segs; cur; cur = cur->next) {
+ /* 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);
+
+ /* all segs are gso_size, except for last */
+ if (cur->next) {
+ KUNIT_ASSERT_EQ(test, cur->len, sizeof(hdr) + gso_size);
+ } else {
+ KUNIT_ASSERT_EQ(test, cur->len, sizeof(hdr) + last_seg_size);
+
+ /* last seg can be found through segs->prev pointer */
+ KUNIT_ASSERT_PTR_EQ(test, cur, segs->prev);
+ }
+ }
+
+ consume_skb(segs);
+free_gso_skb:
+ consume_skb(skb);
+}
+
+static struct kunit_case gso_test_cases[] = {
+ KUNIT_CASE(gso_test_func),
+ {}
+};
+
+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");