| Message ID | 20200803231045.2683198-1-kafai@fb.com |
|---|---|
| State | RFC |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | BPF TCP header options | expand |
Martin KaFai Lau wrote: > In tcp_init_transfer(), it currently calls the bpf prog to give it a > chance to handle the just "ESTABLISHED" event (e.g. do setsockopt > on the newly established sk). Right now, it is done by calling the > general purpose tcp_call_bpf(). > > In the later patch, it also needs to pass the just-received skb which > concludes the 3 way handshake. E.g. the SYNACK received at the active side. > The bpf prog can then learn some specific header options written by the > peer's bpf-prog and potentially do setsockopt on the newly established sk. > Thus, instead of reusing the general purpose tcp_call_bpf(), a new function > bpf_skops_established() is added to allow passing the "skb" to the bpf prog. > The actual skb passing from bpf_skops_established() to the bpf prog > will happen together in a later patch which has the necessary bpf pieces. > > A "skb" arg is also added to tcp_init_transfer() such that > it can then be passed to bpf_skops_established(). > > Calling the new bpf_skops_established() instead of tcp_call_bpf() > should be a noop in this patch. Yep, looks like a noop. > > Signed-off-by: Martin KaFai Lau <kafai@fb.com> Acked-by: John Fastabend <john.fastabend@gmail.com> [...] > > +#ifdef CONFIG_CGROUP_BPF > +static void bpf_skops_established(struct sock *sk, int bpf_op, > + struct sk_buff *skb) Small nit because its an RFC anyways. Should we call this bpf_skops_fullsock(...) instead? Just a suggestion. > +{ > + struct bpf_sock_ops_kern sock_ops; > + > + sock_owned_by_me(sk); > + > + memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp)); > + sock_ops.op = bpf_op; > + sock_ops.is_fullsock = 1; > + sock_ops.sk = sk; > + /* skb will be passed to the bpf prog in a later patch. */ > + > + BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops); > +}
On Mon, Aug 03, 2020 at 06:28:04PM -0700, John Fastabend wrote: > Martin KaFai Lau wrote: > > In tcp_init_transfer(), it currently calls the bpf prog to give it a > > chance to handle the just "ESTABLISHED" event (e.g. do setsockopt > > on the newly established sk). Right now, it is done by calling the > > general purpose tcp_call_bpf(). > > > > In the later patch, it also needs to pass the just-received skb which > > concludes the 3 way handshake. E.g. the SYNACK received at the active side. > > The bpf prog can then learn some specific header options written by the > > peer's bpf-prog and potentially do setsockopt on the newly established sk. > > Thus, instead of reusing the general purpose tcp_call_bpf(), a new function > > bpf_skops_established() is added to allow passing the "skb" to the bpf prog. > > The actual skb passing from bpf_skops_established() to the bpf prog > > will happen together in a later patch which has the necessary bpf pieces. > > > > A "skb" arg is also added to tcp_init_transfer() such that > > it can then be passed to bpf_skops_established(). > > > > Calling the new bpf_skops_established() instead of tcp_call_bpf() > > should be a noop in this patch. > > Yep, looks like a noop. > > > > > Signed-off-by: Martin KaFai Lau <kafai@fb.com> > > Acked-by: John Fastabend <john.fastabend@gmail.com> > > [...] > > > > > +#ifdef CONFIG_CGROUP_BPF > > +static void bpf_skops_established(struct sock *sk, int bpf_op, > > + struct sk_buff *skb) > > > Small nit because its an RFC anyways. > > Should we call this bpf_skops_fullsock(...) instead? Just a suggestion. I prefer to stay with the current suffix "_established" which names after the sock_ops->op that it is calling. I think it is understood that established sk is a fullsock.
diff --git a/include/net/tcp.h b/include/net/tcp.h index 895e7aabf136..ae18c2b222a3 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -394,7 +394,7 @@ void tcp_metrics_init(void); bool tcp_peer_is_proven(struct request_sock *req, struct dst_entry *dst); void tcp_close(struct sock *sk, long timeout); void tcp_init_sock(struct sock *sk); -void tcp_init_transfer(struct sock *sk, int bpf_op); +void tcp_init_transfer(struct sock *sk, int bpf_op, struct sk_buff *skb); __poll_t tcp_poll(struct file *file, struct socket *sock, struct poll_table_struct *wait); int tcp_getsockopt(struct sock *sk, int level, int optname, diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c index 19ad9586c720..d53190302087 100644 --- a/net/ipv4/tcp_fastopen.c +++ b/net/ipv4/tcp_fastopen.c @@ -272,7 +272,7 @@ static struct sock *tcp_fastopen_create_child(struct sock *sk, refcount_set(&req->rsk_refcnt, 2); /* Now finish processing the fastopen child socket. */ - tcp_init_transfer(child, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB); + tcp_init_transfer(child, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB, skb); tp->rcv_nxt = TCP_SKB_CB(skb)->seq + 1; diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index c1d2fb507701..9a8fb41676bc 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -138,6 +138,29 @@ void clean_acked_data_flush(void) EXPORT_SYMBOL_GPL(clean_acked_data_flush); #endif +#ifdef CONFIG_CGROUP_BPF +static void bpf_skops_established(struct sock *sk, int bpf_op, + struct sk_buff *skb) +{ + struct bpf_sock_ops_kern sock_ops; + + sock_owned_by_me(sk); + + memset(&sock_ops, 0, offsetof(struct bpf_sock_ops_kern, temp)); + sock_ops.op = bpf_op; + sock_ops.is_fullsock = 1; + sock_ops.sk = sk; + /* skb will be passed to the bpf prog in a later patch. */ + + BPF_CGROUP_RUN_PROG_SOCK_OPS(&sock_ops); +} +#else +static void bpf_skops_established(struct sock *sk, int bpf_op, + struct sk_buff *skb) +{ +} +#endif + static void tcp_gro_dev_warn(struct sock *sk, const struct sk_buff *skb, unsigned int len) { @@ -5806,7 +5829,7 @@ void tcp_rcv_established(struct sock *sk, struct sk_buff *skb) } EXPORT_SYMBOL(tcp_rcv_established); -void tcp_init_transfer(struct sock *sk, int bpf_op) +void tcp_init_transfer(struct sock *sk, int bpf_op, struct sk_buff *skb) { struct inet_connection_sock *icsk = inet_csk(sk); struct tcp_sock *tp = tcp_sk(sk); @@ -5827,7 +5850,7 @@ void tcp_init_transfer(struct sock *sk, int bpf_op) tp->snd_cwnd = tcp_init_cwnd(tp, __sk_dst_get(sk)); tp->snd_cwnd_stamp = tcp_jiffies32; - tcp_call_bpf(sk, bpf_op, 0, NULL); + bpf_skops_established(sk, bpf_op, skb); tcp_init_congestion_control(sk); tcp_init_buffer_space(sk); } @@ -5846,7 +5869,7 @@ void tcp_finish_connect(struct sock *sk, struct sk_buff *skb) sk_mark_napi_id(sk, skb); } - tcp_init_transfer(sk, BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB); + tcp_init_transfer(sk, BPF_SOCK_OPS_ACTIVE_ESTABLISHED_CB, skb); /* Prevent spurious tcp_cwnd_restart() on first data * packet. @@ -6318,7 +6341,8 @@ int tcp_rcv_state_process(struct sock *sk, struct sk_buff *skb) } else { tcp_try_undo_spurious_syn(sk); tp->retrans_stamp = 0; - tcp_init_transfer(sk, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB); + tcp_init_transfer(sk, BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB, + skb); WRITE_ONCE(tp->copied_seq, tp->rcv_nxt); } smp_mb();
In tcp_init_transfer(), it currently calls the bpf prog to give it a chance to handle the just "ESTABLISHED" event (e.g. do setsockopt on the newly established sk). Right now, it is done by calling the general purpose tcp_call_bpf(). In the later patch, it also needs to pass the just-received skb which concludes the 3 way handshake. E.g. the SYNACK received at the active side. The bpf prog can then learn some specific header options written by the peer's bpf-prog and potentially do setsockopt on the newly established sk. Thus, instead of reusing the general purpose tcp_call_bpf(), a new function bpf_skops_established() is added to allow passing the "skb" to the bpf prog. The actual skb passing from bpf_skops_established() to the bpf prog will happen together in a later patch which has the necessary bpf pieces. A "skb" arg is also added to tcp_init_transfer() such that it can then be passed to bpf_skops_established(). Calling the new bpf_skops_established() instead of tcp_call_bpf() should be a noop in this patch. Signed-off-by: Martin KaFai Lau <kafai@fb.com> --- include/net/tcp.h | 2 +- net/ipv4/tcp_fastopen.c | 2 +- net/ipv4/tcp_input.c | 32 ++++++++++++++++++++++++++++---- 3 files changed, 30 insertions(+), 6 deletions(-)