leandrof/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

skmsg: Move sk_redir from TCP_SKB_CB to skb

Browse Source 
Currently TCP_SKB_CB() is hard-coded in skmsg code, it certainly
does not work for any other non-TCP protocols. We can move them to
skb ext, but it introduces a memory allocation on fast path.

Fortunately, we only need to a word-size to store all the information,
because the flags actually only contains 1 bit so can be just packed
into the lowest bit of the "pointer", which is stored as unsigned
long.

Inside struct sk_buff, '_skb_refdst' can be reused because skb dst is
no longer needed after ->sk_data_ready() so we can just drop it.

Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Jakub Sitnicki <jakub@cloudflare.com>
Link: https://lore.kernel.org/bpf/20210223184934.6054-5-xiyou.wangcong@gmail.com
This commit is contained in:
Cong Wang
2021-02-23 10:49:29 -08:00
committed by Alexei Starovoitov
parent 16137b09a6
commit e3526bb92a
5 changed files with 62 additions and 37 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
include/net/tcp.h
View File

@@ -883,30 +883,11 @@ struct tcp_skb_cb {
struct inet6_skb_parm h6;
#endif
} header; /* For incoming skbs */
struct {
__u32 flags;
struct sock *sk_redir;
} bpf;
};
};
#define TCP_SKB_CB(__skb) ((struct tcp_skb_cb *)&((__skb)->cb[0]))
static inline bool tcp_skb_bpf_ingress(const struct sk_buff *skb)
{
return TCP_SKB_CB(skb)->bpf.flags & BPF_F_INGRESS;
}
static inline struct sock *tcp_skb_bpf_redirect_fetch(struct sk_buff *skb)
{
return TCP_SKB_CB(skb)->bpf.sk_redir;
}
static inline void tcp_skb_bpf_redirect_clear(struct sk_buff *skb)
{
TCP_SKB_CB(skb)->bpf.sk_redir = NULL;
}
extern const struct inet_connection_sock_af_ops ipv4_specific;
#if IS_ENABLED(CONFIG_IPV6)