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Message-ID: <20200925000356.3856047-1-kafai@fb.com>
Date: Thu, 24 Sep 2020 17:03:56 -0700
From: Martin KaFai Lau <kafai@...com>
To: <bpf@...r.kernel.org>
CC: Alexei Starovoitov <ast@...nel.org>,
Daniel Borkmann <daniel@...earbox.net>, <kernel-team@...com>,
Lorenz Bauer <lmb@...udflare.com>, <netdev@...r.kernel.org>
Subject: [PATCH v4 bpf-next 03/13] bpf: Change bpf_sk_release and bpf_sk_*cgroup_id to accept ARG_PTR_TO_BTF_ID_SOCK_COMMON
The previous patch allows the networking bpf prog to use the
bpf_skc_to_*() helpers to get a PTR_TO_BTF_ID socket pointer,
e.g. "struct tcp_sock *". It allows the bpf prog to read all the
fields of the tcp_sock.
This patch changes the bpf_sk_release() and bpf_sk_*cgroup_id()
to take ARG_PTR_TO_BTF_ID_SOCK_COMMON such that they will
work with the pointer returned by the bpf_skc_to_*() helpers
also. For example, the following will work:
sk = bpf_skc_lookup_tcp(skb, tuple, tuplen, BPF_F_CURRENT_NETNS, 0);
if (!sk)
return;
tp = bpf_skc_to_tcp_sock(sk);
if (!tp) {
bpf_sk_release(sk);
return;
}
lsndtime = tp->lsndtime;
/* Pass tp to bpf_sk_release() will also work */
bpf_sk_release(tp);
Since PTR_TO_BTF_ID could be NULL, the helper taking
ARG_PTR_TO_BTF_ID_SOCK_COMMON has to check for NULL at runtime.
A btf_id of "struct sock" may not always mean a fullsock. Regardless
the helper's running context may get a non-fullsock or not,
considering fullsock check/handling is pretty cheap, it is better to
keep the same verifier expectation on helper that takes ARG_PTR_TO_BTF_ID*
will be able to handle the minisock situation. In the bpf_sk_*cgroup_id()
case, it will try to get a fullsock by using sk_to_full_sk() as its
skb variant bpf_sk"b"_*cgroup_id() has already been doing.
bpf_sk_release can already handle minisock, so nothing special has to
be done.
Signed-off-by: Martin KaFai Lau <kafai@...com>
---
include/uapi/linux/bpf.h | 8 ++++----
net/core/filter.c | 30 ++++++++++++++----------------
tools/include/uapi/linux/bpf.h | 8 ++++----
3 files changed, 22 insertions(+), 24 deletions(-)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index a22812561064..c96a56d9c3be 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -2512,7 +2512,7 @@ union bpf_attr {
* result is from *reuse*\ **->socks**\ [] using the hash of the
* tuple.
*
- * long bpf_sk_release(struct bpf_sock *sock)
+ * long bpf_sk_release(void *sock)
* Description
* Release the reference held by *sock*. *sock* must be a
* non-**NULL** pointer that was returned from
@@ -3234,11 +3234,11 @@ union bpf_attr {
*
* **-EOVERFLOW** if an overflow happened: The same object will be tried again.
*
- * u64 bpf_sk_cgroup_id(struct bpf_sock *sk)
+ * u64 bpf_sk_cgroup_id(void *sk)
* Description
* Return the cgroup v2 id of the socket *sk*.
*
- * *sk* must be a non-**NULL** pointer to a full socket, e.g. one
+ * *sk* must be a non-**NULL** pointer to a socket, e.g. one
* returned from **bpf_sk_lookup_xxx**\ (),
* **bpf_sk_fullsock**\ (), etc. The format of returned id is
* same as in **bpf_skb_cgroup_id**\ ().
@@ -3248,7 +3248,7 @@ union bpf_attr {
* Return
* The id is returned or 0 in case the id could not be retrieved.
*
- * u64 bpf_sk_ancestor_cgroup_id(struct bpf_sock *sk, int ancestor_level)
+ * u64 bpf_sk_ancestor_cgroup_id(void *sk, int ancestor_level)
* Description
* Return id of cgroup v2 that is ancestor of cgroup associated
* with the *sk* at the *ancestor_level*. The root cgroup is at
diff --git a/net/core/filter.c b/net/core/filter.c
index 6d1864f2bd51..06d397eeef2a 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -4088,18 +4088,17 @@ static inline u64 __bpf_sk_cgroup_id(struct sock *sk)
{
struct cgroup *cgrp;
+ sk = sk_to_full_sk(sk);
+ if (!sk || !sk_fullsock(sk))
+ return 0;
+
cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
return cgroup_id(cgrp);
}
BPF_CALL_1(bpf_skb_cgroup_id, const struct sk_buff *, skb)
{
- struct sock *sk = skb_to_full_sk(skb);
-
- if (!sk || !sk_fullsock(sk))
- return 0;
-
- return __bpf_sk_cgroup_id(sk);
+ return __bpf_sk_cgroup_id(skb->sk);
}
static const struct bpf_func_proto bpf_skb_cgroup_id_proto = {
@@ -4115,6 +4114,10 @@ static inline u64 __bpf_sk_ancestor_cgroup_id(struct sock *sk,
struct cgroup *ancestor;
struct cgroup *cgrp;
+ sk = sk_to_full_sk(sk);
+ if (!sk || !sk_fullsock(sk))
+ return 0;
+
cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
ancestor = cgroup_ancestor(cgrp, ancestor_level);
if (!ancestor)
@@ -4126,12 +4129,7 @@ static inline u64 __bpf_sk_ancestor_cgroup_id(struct sock *sk,
BPF_CALL_2(bpf_skb_ancestor_cgroup_id, const struct sk_buff *, skb, int,
ancestor_level)
{
- struct sock *sk = skb_to_full_sk(skb);
-
- if (!sk || !sk_fullsock(sk))
- return 0;
-
- return __bpf_sk_ancestor_cgroup_id(sk, ancestor_level);
+ return __bpf_sk_ancestor_cgroup_id(skb->sk, ancestor_level);
}
static const struct bpf_func_proto bpf_skb_ancestor_cgroup_id_proto = {
@@ -4151,7 +4149,7 @@ static const struct bpf_func_proto bpf_sk_cgroup_id_proto = {
.func = bpf_sk_cgroup_id,
.gpl_only = false,
.ret_type = RET_INTEGER,
- .arg1_type = ARG_PTR_TO_SOCKET,
+ .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
};
BPF_CALL_2(bpf_sk_ancestor_cgroup_id, struct sock *, sk, int, ancestor_level)
@@ -4163,7 +4161,7 @@ static const struct bpf_func_proto bpf_sk_ancestor_cgroup_id_proto = {
.func = bpf_sk_ancestor_cgroup_id,
.gpl_only = false,
.ret_type = RET_INTEGER,
- .arg1_type = ARG_PTR_TO_SOCKET,
+ .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
.arg2_type = ARG_ANYTHING,
};
#endif
@@ -5697,7 +5695,7 @@ static const struct bpf_func_proto bpf_sk_lookup_udp_proto = {
BPF_CALL_1(bpf_sk_release, struct sock *, sk)
{
- if (sk_is_refcounted(sk))
+ if (sk && sk_is_refcounted(sk))
sock_gen_put(sk);
return 0;
}
@@ -5706,7 +5704,7 @@ static const struct bpf_func_proto bpf_sk_release_proto = {
.func = bpf_sk_release,
.gpl_only = false,
.ret_type = RET_INTEGER,
- .arg1_type = ARG_PTR_TO_SOCK_COMMON,
+ .arg1_type = ARG_PTR_TO_BTF_ID_SOCK_COMMON,
};
BPF_CALL_5(bpf_xdp_sk_lookup_udp, struct xdp_buff *, ctx,
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index a22812561064..c96a56d9c3be 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -2512,7 +2512,7 @@ union bpf_attr {
* result is from *reuse*\ **->socks**\ [] using the hash of the
* tuple.
*
- * long bpf_sk_release(struct bpf_sock *sock)
+ * long bpf_sk_release(void *sock)
* Description
* Release the reference held by *sock*. *sock* must be a
* non-**NULL** pointer that was returned from
@@ -3234,11 +3234,11 @@ union bpf_attr {
*
* **-EOVERFLOW** if an overflow happened: The same object will be tried again.
*
- * u64 bpf_sk_cgroup_id(struct bpf_sock *sk)
+ * u64 bpf_sk_cgroup_id(void *sk)
* Description
* Return the cgroup v2 id of the socket *sk*.
*
- * *sk* must be a non-**NULL** pointer to a full socket, e.g. one
+ * *sk* must be a non-**NULL** pointer to a socket, e.g. one
* returned from **bpf_sk_lookup_xxx**\ (),
* **bpf_sk_fullsock**\ (), etc. The format of returned id is
* same as in **bpf_skb_cgroup_id**\ ().
@@ -3248,7 +3248,7 @@ union bpf_attr {
* Return
* The id is returned or 0 in case the id could not be retrieved.
*
- * u64 bpf_sk_ancestor_cgroup_id(struct bpf_sock *sk, int ancestor_level)
+ * u64 bpf_sk_ancestor_cgroup_id(void *sk, int ancestor_level)
* Description
* Return id of cgroup v2 that is ancestor of cgroup associated
* with the *sk* at the *ancestor_level*. The root cgroup is at
--
2.24.1
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