On Tue, Feb 25, 2020 at 01:56:33PM +0000, Lorenz Bauer wrote:
> Add basic psock hooks for UDP sockets. This allows adding and
> removing sockets, as well as automatic removal on unhash and close.
>
> Signed-off-by: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
> ---
> MAINTAINERS | 1 +
> include/linux/udp.h | 4 ++++
> net/core/sock_map.c | 47 +++++++++++++++++++++++-----------------
> net/ipv4/Makefile | 1 +
> net/ipv4/udp_bpf.c | 53 +++++++++++++++++++++++++++++++++++++++++++++
> 5 files changed, 86 insertions(+), 20 deletions(-)
> create mode 100644 net/ipv4/udp_bpf.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 2af5fa73155e..495ba52038ad 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -9358,6 +9358,7 @@ F: include/linux/skmsg.h
> F: net/core/skmsg.c
> F: net/core/sock_map.c
> F: net/ipv4/tcp_bpf.c
> +F: net/ipv4/udp_bpf.c
>
> LANTIQ / INTEL Ethernet drivers
> M: Hauke Mehrtens <hauke@xxxxxxxxxx>
> diff --git a/include/linux/udp.h b/include/linux/udp.h
> index aa84597bdc33..d90d8fd5f73d 100644
> --- a/include/linux/udp.h
> +++ b/include/linux/udp.h
> @@ -143,4 +143,8 @@ static inline bool udp_unexpected_gso(struct sock *sk, struct sk_buff *skb)
>
> #define IS_UDPLITE(__sk) (__sk->sk_protocol == IPPROTO_UDPLITE)
>
> +#if defined(CONFIG_NET_SOCK_MSG)
> +int udp_bpf_init(struct sock *sk);
> +#endif
> +
> #endif /* _LINUX_UDP_H */
> diff --git a/net/core/sock_map.c b/net/core/sock_map.c
> index c84cc9fc7f6b..f998192c425f 100644
> --- a/net/core/sock_map.c
> +++ b/net/core/sock_map.c
> @@ -153,7 +153,7 @@ static struct sk_psock *sock_map_psock_get_checked(struct sock *sk)
> rcu_read_lock();
> psock = sk_psock(sk);
> if (psock) {
> - if (sk->sk_prot->recvmsg != tcp_bpf_recvmsg) {
> + if (sk->sk_prot->close != sock_map_close) {
> psock = ERR_PTR(-EBUSY);
> goto out;
> }
> @@ -166,6 +166,14 @@ static struct sk_psock *sock_map_psock_get_checked(struct sock *sk)
> return psock;
> }
>
> +static int sock_map_init_hooks(struct sock *sk)
> +{
> + if (sk->sk_type == SOCK_DGRAM)
> + return udp_bpf_init(sk);
> + else
> + return tcp_bpf_init(sk);
> +}
> +
> static int sock_map_link(struct bpf_map *map, struct sk_psock_progs *progs,
> struct sock *sk)
> {
> @@ -220,7 +228,7 @@ static int sock_map_link(struct bpf_map *map, struct sk_psock_progs *progs,
> if (msg_parser)
> psock_set_prog(&psock->progs.msg_parser, msg_parser);
>
> - ret = tcp_bpf_init(sk);
> + ret = sock_map_init_hooks(sk);
> if (ret < 0)
> goto out_drop;
>
> @@ -267,7 +275,7 @@ static int sock_map_link_no_progs(struct bpf_map *map, struct sock *sk)
> return -ENOMEM;
>
> init:
> - ret = tcp_bpf_init(sk);
> + ret = sock_map_init_hooks(sk);
> if (ret < 0)
> sk_psock_put(sk, psock);
> return ret;
> @@ -394,9 +402,14 @@ static int sock_map_get_next_key(struct bpf_map *map, void *key, void *next)
> return 0;
> }
>
> +static bool sock_map_sk_is_tcp(const struct sock *sk)
> +{
> + return sk->sk_type == SOCK_STREAM && sk->sk_protocol == IPPROTO_TCP;
> +}
> +
> static bool sock_map_redirect_allowed(const struct sock *sk)
> {
> - return sk->sk_state != TCP_LISTEN;
> + return sock_map_sk_is_tcp(sk) && sk->sk_state != TCP_LISTEN;
> }
>
> static int sock_map_update_common(struct bpf_map *map, u32 idx,
> @@ -466,15 +479,17 @@ static bool sock_map_op_okay(const struct bpf_sock_ops_kern *ops)
> ops->op == BPF_SOCK_OPS_TCP_LISTEN_CB;
> }
>
> +static bool sock_map_sk_is_udp(const struct sock *sk)
> +{
> + return sk->sk_type == SOCK_DGRAM && sk->sk_protocol == IPPROTO_UDP;
> +}
> +
> static bool sock_map_sk_is_suitable(const struct sock *sk)
> {
> - return sk->sk_type == SOCK_STREAM &&
> - sk->sk_protocol == IPPROTO_TCP;
> -}
> + const int tcp_flags = TCPF_ESTABLISHED | TCPF_LISTEN | TCPF_SYN_RECV;
hmm... I thought this patch is for adding UDP only. However, if I read
it correctly, the tcp_flags is changed (| TCPF_SYN_RECV)?
Please elaborate in the commit message.
>
> -static bool sock_map_sk_state_allowed(const struct sock *sk)
> -{
> - return (1 << sk->sk_state) & (TCPF_ESTABLISHED | TCPF_LISTEN);
> + return (sock_map_sk_is_udp(sk) && sk_hashed(sk)) ||
> + (sock_map_sk_is_tcp(sk) && (1 << sk->sk_state) & tcp_flags);
> }
>
> static int sock_map_update_elem(struct bpf_map *map, void *key,
