From: John Fastabend <john.fastabend@gmail.com>
Date: Wed, 1 Nov 2017 02:17:31 +0000 (-0700)
Subject: bpf: remove SK_REDIRECT from UAPI
X-Git-Url: http://git.lede-project.org./?a=commitdiff_plain;h=04686ef299db5ff299bfc5a4504b189e46842078;p=openwrt%2Fstaging%2Fblogic.git

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 0d7948ce2128..7bf4c750dd3a 100644
--- 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 66f00a2b27f4..dbd7b322a86b 100644
--- 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 c174971afbe6..01cc7ba39924 100644
--- 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