bpf: when doing BPF_PROG_TEST_RUN for flow dissector use no-skb mode

Now that we have bpf_flow_dissect which can work on raw data,
use it when doing BPF_PROG_TEST_RUN for flow dissector.

Simplifies bpf_prog_test_run_flow_dissector and allows us to
test no-skb mode.

Note, that previously, with bpf_flow_dissect_skb we used to call
eth_type_trans which pulled L2 (ETH_HLEN) header and we explicitly called
skb_reset_network_header. That means flow_keys->nhoff would be
initialized to 0 (skb_network_offset) in init_flow_keys.
Now we call bpf_flow_dissect with nhoff set to ETH_HLEN and need
to undo it once the dissection is done to preserve the existing behavior.

Signed-off-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 006ad86..db2ec88 100644 (file)
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -379,12 +379,12 @@ int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,
                                     union bpf_attr __user *uattr)
 {
        u32 size = kattr->test.data_size_in;
+       struct bpf_flow_dissector ctx = {};
        u32 repeat = kattr->test.repeat;
        struct bpf_flow_keys flow_keys;
        u64 time_start, time_spent = 0;
+       const struct ethhdr *eth;
        u32 retval, duration;
-       struct sk_buff *skb;
-       struct sock *sk;
        void *data;
        int ret;
        u32 i;
@@ -395,43 +395,31 @@ int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,
        if (kattr->test.ctx_in || kattr->test.ctx_out)
                return -EINVAL;
 
-       data = bpf_test_init(kattr, size, NET_SKB_PAD + NET_IP_ALIGN,
-                            SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
+       if (size < ETH_HLEN)
+               return -EINVAL;
+
+       data = bpf_test_init(kattr, size, 0, 0);
        if (IS_ERR(data))
                return PTR_ERR(data);
 
-       sk = kzalloc(sizeof(*sk), GFP_USER);
-       if (!sk) {
-               kfree(data);
-               return -ENOMEM;
-       }
-       sock_net_set(sk, current->nsproxy->net_ns);
-       sock_init_data(NULL, sk);
-
-       skb = build_skb(data, 0);
-       if (!skb) {
-               kfree(data);
-               kfree(sk);
-               return -ENOMEM;
-       }
-       skb->sk = sk;
-
-       skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
-       __skb_put(skb, size);
-       skb->protocol = eth_type_trans(skb,
-                                      current->nsproxy->net_ns->loopback_dev);
-       skb_reset_network_header(skb);
+       eth = (struct ethhdr *)data;
 
        if (!repeat)
                repeat = 1;
 
+       ctx.flow_keys = &flow_keys;
+       ctx.data = data;
+       ctx.data_end = (__u8 *)data + size;
+
        rcu_read_lock();
        preempt_disable();
        time_start = ktime_get_ns();
        for (i = 0; i < repeat; i++) {
-               retval = __skb_flow_bpf_dissect(prog, skb,
-                                               &flow_keys_dissector,
-                                               &flow_keys);
+               retval = bpf_flow_dissect(prog, &ctx, eth->h_proto, ETH_HLEN,
+                                         size);
+
+               flow_keys.nhoff -= ETH_HLEN;
+               flow_keys.thoff -= ETH_HLEN;
 
                if (signal_pending(current)) {
                        preempt_enable();
@@ -464,7 +452,6 @@ int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,
                              retval, duration);
 
 out:
-       kfree_skb(skb);
-       kfree(sk);
+       kfree(data);
        return ret;
 }