test_bpf: allow tests to specify an skb fragment.

This introduce a new test->aux flag (FLAG_SKB_FRAG) to tell the
populate_skb() function to add a fragment to the test skb containing
the data specified in test->frag_data).

Signed-off-by: Nicolas Schichan <nschichan@freebox.fr>
Acked-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/lib/test_bpf.c b/lib/test_bpf.c
index 6843d0b..e261751 100644 (file)
--- a/lib/test_bpf.c
+++ b/lib/test_bpf.c
@@ -23,6 +23,7 @@
 #include <linux/netdevice.h>
 #include <linux/if_vlan.h>
 #include <linux/random.h>
+#include <linux/highmem.h>
 
 /* General test specific settings */
 #define MAX_SUBTESTS   3
@@ -56,6 +57,7 @@
 /* Flags that can be passed to test cases */
 #define FLAG_NO_DATA           BIT(0)
 #define FLAG_EXPECTED_FAIL     BIT(1)
+#define FLAG_SKB_FRAG          BIT(2)
 
 enum {
        CLASSIC  = BIT(6),      /* Old BPF instructions only. */
@@ -81,6 +83,7 @@ struct bpf_test {
                __u32 result;
        } test[MAX_SUBTESTS];
        int (*fill_helper)(struct bpf_test *self);
+       __u8 frag_data[MAX_DATA];
 };
 
 /* Large test cases need separate allocation and fill handler. */
@@ -4525,6 +4528,9 @@ static struct sk_buff *populate_skb(char *buf, int size)
 
 static void *generate_test_data(struct bpf_test *test, int sub)
 {
+       struct sk_buff *skb;
+       struct page *page;
+
        if (test->aux & FLAG_NO_DATA)
                return NULL;
 
@@ -4532,7 +4538,38 @@ static void *generate_test_data(struct bpf_test *test, int sub)
         * subtests generate skbs of different sizes based on
         * the same data.
         */
-       return populate_skb(test->data, test->test[sub].data_size);
+       skb = populate_skb(test->data, test->test[sub].data_size);
+       if (!skb)
+               return NULL;
+
+       if (test->aux & FLAG_SKB_FRAG) {
+               /*
+                * when the test requires a fragmented skb, add a
+                * single fragment to the skb, filled with
+                * test->frag_data.
+                */
+               void *ptr;
+
+               page = alloc_page(GFP_KERNEL);
+
+               if (!page)
+                       goto err_kfree_skb;
+
+               ptr = kmap(page);
+               if (!ptr)
+                       goto err_free_page;
+               memcpy(ptr, test->frag_data, MAX_DATA);
+               kunmap(page);
+               skb_add_rx_frag(skb, 0, page, 0, MAX_DATA, MAX_DATA);
+       }
+
+       return skb;
+
+err_free_page:
+       __free_page(page);
+err_kfree_skb:
+       kfree_skb(skb);
+       return NULL;
 }
 
 static void release_test_data(const struct bpf_test *test, void *data)