bpf: remove SK_REDIRECT from UAPI

Now that SK_REDIRECT is no longer a valid return code. Remove it
from the UAPI completely. Then do a namespace remapping internal
to sockmap so SK_REDIRECT is no longer externally visible.

Patchs primary change is to do a namechange from SK_REDIRECT to
__SK_REDIRECT

Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 0d7948c..7bf4c75 100644 (file)
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -788,7 +788,6 @@ struct xdp_md {
 enum sk_action {
        SK_DROP = 0,
        SK_PASS,
-       SK_REDIRECT,
 };
 
 #define BPF_TAG_SIZE   8

diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c
index 66f00a2..dbd7b32 100644 (file)
--- a/kernel/bpf/sockmap.c
+++ b/kernel/bpf/sockmap.c
@@ -101,13 +101,19 @@ static inline void bpf_compute_data_end_sk_skb(struct sk_buff *skb)
        TCP_SKB_CB(skb)->bpf.data_end = skb->data + skb_headlen(skb);
 }
 
+enum __sk_action {
+       __SK_DROP = 0,
+       __SK_PASS,
+       __SK_REDIRECT,
+};
+
 static int smap_verdict_func(struct smap_psock *psock, struct sk_buff *skb)
 {
        struct bpf_prog *prog = READ_ONCE(psock->bpf_verdict);
        int rc;
 
        if (unlikely(!prog))
-               return SK_DROP;
+               return __SK_DROP;
 
        skb_orphan(skb);
        /* We need to ensure that BPF metadata for maps is also cleared
@@ -122,8 +128,10 @@ static int smap_verdict_func(struct smap_psock *psock, struct sk_buff *skb)
        preempt_enable();
        skb->sk = NULL;
 
+       /* Moving return codes from UAPI namespace into internal namespace */
        return rc == SK_PASS ?
-               (TCP_SKB_CB(skb)->bpf.map ? SK_REDIRECT : SK_PASS) : SK_DROP;
+               (TCP_SKB_CB(skb)->bpf.map ? __SK_REDIRECT : __SK_PASS) :
+               __SK_DROP;
 }
 
 static void smap_do_verdict(struct smap_psock *psock, struct sk_buff *skb)
@@ -133,7 +141,7 @@ static void smap_do_verdict(struct smap_psock *psock, struct sk_buff *skb)
 
        rc = smap_verdict_func(psock, skb);
        switch (rc) {
-       case SK_REDIRECT:
+       case __SK_REDIRECT:
                sk = do_sk_redirect_map(skb);
                if (likely(sk)) {
                        struct smap_psock *peer = smap_psock_sk(sk);
@@ -149,7 +157,7 @@ static void smap_do_verdict(struct smap_psock *psock, struct sk_buff *skb)
                        }
                }
        /* Fall through and free skb otherwise */
-       case SK_DROP:
+       case __SK_DROP:
        default:
                kfree_skb(skb);
        }

diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index c174971..01cc7ba 100644 (file)
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -576,7 +576,7 @@ union bpf_attr {
  *     @map: pointer to sockmap
  *     @key: key to lookup sock in map
  *     @flags: reserved for future use
- *     Return: SK_REDIRECT
+ *     Return: SK_PASS
  *
  * int bpf_sock_map_update(skops, map, key, flags)
  *     @skops: pointer to bpf_sock_ops
@@ -789,7 +789,6 @@ struct xdp_md {
 enum sk_action {
        SK_DROP = 0,
        SK_PASS,
-       SK_REDIRECT,
 };
 
 #define BPF_TAG_SIZE   8