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[83.31.64.64]) by smtp.gmail.com with ESMTPSA id e11sm1897855ljk.128.2021.05.07.06.29.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 07 May 2021 06:29:45 -0700 (PDT) References: <20210426025001.7899-1-xiyou.wangcong@gmail.com> <20210426025001.7899-6-xiyou.wangcong@gmail.com> User-agent: mu4e 1.1.0; emacs 27.2 From: Jakub Sitnicki To: Cong Wang Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, jiang.wang@bytedance.com, duanxiongchun@bytedance.com, wangdongdong.6@bytedance.com, Cong Wang , John Fastabend , Daniel Borkmann , Lorenz Bauer Subject: Re: [Patch bpf-next v3 05/10] af_unix: implement unix_dgram_bpf_recvmsg() In-reply-to: <20210426025001.7899-6-xiyou.wangcong@gmail.com> Date: Fri, 07 May 2021 15:29:43 +0200 Message-ID: <87lf8qvfi0.fsf@cloudflare.com> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Mon, Apr 26, 2021 at 04:49 AM CEST, Cong Wang wrote: > From: Cong Wang > > We have to implement unix_dgram_bpf_recvmsg() to replace the > original ->recvmsg() to retrieve skmsg from ingress_msg. > > AF_UNIX is again special here because the lack of > sk_prot->recvmsg(). I simply add a special case inside > unix_dgram_recvmsg() to call sk->sk_prot->recvmsg() directly. > > Cc: John Fastabend > Cc: Daniel Borkmann > Cc: Jakub Sitnicki > Cc: Lorenz Bauer > Signed-off-by: Cong Wang > --- > include/net/af_unix.h | 3 +++ > net/unix/af_unix.c | 21 ++++++++++++++++--- > net/unix/unix_bpf.c | 49 +++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 70 insertions(+), 3 deletions(-) > > diff --git a/include/net/af_unix.h b/include/net/af_unix.h > index cca645846af1..e524c82794c9 100644 > --- a/include/net/af_unix.h > +++ b/include/net/af_unix.h > @@ -82,6 +82,9 @@ static inline struct unix_sock *unix_sk(const struct sock *sk) > long unix_inq_len(struct sock *sk); > long unix_outq_len(struct sock *sk); > > +int __unix_dgram_recvmsg(struct sock *sk, struct msghdr *msg, size_t size, > + int nonblock, int flags, int *addr_len); > + > #ifdef CONFIG_SYSCTL > int unix_sysctl_register(struct net *net); > void unix_sysctl_unregister(struct net *net); > diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c > index c4afc5fbe137..08458fa9f48b 100644 > --- a/net/unix/af_unix.c > +++ b/net/unix/af_unix.c > @@ -2088,11 +2088,11 @@ static void unix_copy_addr(struct msghdr *msg, struct sock *sk) > } > } > > -static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg, > - size_t size, int flags) > +int __unix_dgram_recvmsg(struct sock *sk, struct msghdr *msg, size_t size, > + int nonblock, int flags, int *addr_len) > { > struct scm_cookie scm; > - struct sock *sk = sock->sk; > + struct socket *sock = sk->sk_socket; > struct unix_sock *u = unix_sk(sk); > struct sk_buff *skb, *last; > long timeo; > @@ -2195,6 +2195,21 @@ static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg, > return err; > } > > +static int unix_dgram_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, > + int flags) > +{ > + struct sock *sk = sock->sk; > + int addr_len = 0; > + > +#ifdef CONFIG_BPF_SYSCALL > + if (sk->sk_prot != &unix_proto) > + return sk->sk_prot->recvmsg(sk, msg, size, flags & MSG_DONTWAIT, > + flags & ~MSG_DONTWAIT, &addr_len); > +#endif > + return __unix_dgram_recvmsg(sk, msg, size, flags & MSG_DONTWAIT, > + flags, &addr_len); > +} > + Nit: We can just pass NULL instead of &addr_len here it seems. 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