| Message ID | 50885831cb65affbe180d3d9be3ba879f8e331f2.1632666254.git.geliangtang@gmail.com (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | The infinite mapping support | expand |
On Sun, 26 Sep 2021, Geliang Tang wrote: > This patch added a new member last_retrans_seq in mptcp_subflow_context > to track the last retransmitting sequence number. > > Add a new helper named mptcp_is_data_contiguous() to check whether the > data is contiguous on a subflow. > > When a bad checksum is detected and a single contiguous subflow is in use, > don't send RST + MP_FAIL, send data_ack + MP_FAIL instead. > > Suggested-by: Paolo Abeni <pabeni@redhat.com> > Signed-off-by: Geliang Tang <geliangtang@gmail.com> Hi Geliang - I know there's been a lot of churn in this part of the patch series, hopefully we can simplify a little to allow us to merge the first step of infinite mapping send/recv. In v3 and v4 reviews, I suggested tracking the subflow sequence number like you do in this patch. After the discussion in the 2021-09-23 meeting, proper tracking of contiguous data appeared even more complicated, so Paolo had a suggestion to allow fallback in one simple-to-check case: Only do infinite mapping fallback if there is a single subflow AND there have been no retransmissions AND there have never been any MP_JOINs. That can be tracked with a "allow_infinite_fallback" bool in mptcp_sock, which gets initialized to 'true' when the connection begins and is set to 'false' on any retransmit or successful MP_JOIN. Paolo, is that an accurate summary? It's important that this type of fallback only happens when it is guaranteed that the stream is fully in-sequence, otherwise the application's data gets corrupted. The above suggestion lets us merge working infinite mapping code, and then figure out the more complicated "fallback after retransmissions or join" logic in a separate patch series. Thanks, Mat > --- > net/mptcp/protocol.c | 6 ++++++ > net/mptcp/protocol.h | 8 ++++++++ > net/mptcp/subflow.c | 12 ++++++------ > 3 files changed, 20 insertions(+), 6 deletions(-) > > diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c > index f8ad049d6941..cf8cccfefb51 100644 > --- a/net/mptcp/protocol.c > +++ b/net/mptcp/protocol.c > @@ -729,6 +729,9 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk) > if (unlikely(subflow->disposable)) > return; > > + if (!subflow->last_retrans_seq || mptcp_is_data_contiguous(ssk)) > + subflow->last_retrans_seq = tcp_sk(ssk)->snd_una - 1; > + > ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf); > sk_rbuf = READ_ONCE(sk->sk_rcvbuf); > if (unlikely(ssk_rbuf > sk_rbuf)) > @@ -2415,6 +2418,7 @@ static void mptcp_check_fastclose(struct mptcp_sock *msk) > static void __mptcp_retrans(struct sock *sk) > { > struct mptcp_sock *msk = mptcp_sk(sk); > + struct mptcp_subflow_context *subflow; > struct mptcp_sendmsg_info info = {}; > struct mptcp_data_frag *dfrag; > size_t copied = 0; > @@ -2464,6 +2468,8 @@ static void __mptcp_retrans(struct sock *sk) > dfrag->already_sent = max(dfrag->already_sent, info.sent); > tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, > info.size_goal); > + subflow = mptcp_subflow_ctx(ssk); > + subflow->last_retrans_seq = tcp_sk(ssk)->snd_nxt; > } > > release_sock(ssk); > diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h > index 7379ab580a7e..e090a9244f8b 100644 > --- a/net/mptcp/protocol.h > +++ b/net/mptcp/protocol.h > @@ -416,6 +416,7 @@ struct mptcp_subflow_context { > u32 map_data_len; > __wsum map_data_csum; > u32 map_csum_len; > + u32 last_retrans_seq; > u32 request_mptcp : 1, /* send MP_CAPABLE */ > request_join : 1, /* send MP_JOIN */ > request_bkup : 1, > @@ -625,6 +626,13 @@ static inline bool mptcp_has_another_subflow(struct sock *ssk) > return false; > } > > +static inline bool mptcp_is_data_contiguous(struct sock *ssk) > +{ > + struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); > + > + return before(subflow->last_retrans_seq, tcp_sk(ssk)->snd_una); > +} > + > void __init mptcp_proto_init(void); > #if IS_ENABLED(CONFIG_MPTCP_IPV6) > int __init mptcp_proto_v6_init(void); > diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c > index 6172f380dfb7..a8f46a48feb1 100644 > --- a/net/mptcp/subflow.c > +++ b/net/mptcp/subflow.c > @@ -1166,15 +1166,15 @@ static bool subflow_check_data_avail(struct sock *ssk) > fallback: > /* RFC 8684 section 3.7. */ > if (subflow->send_mp_fail) { > - if (mptcp_has_another_subflow(ssk)) { > + if (mptcp_has_another_subflow(ssk) || !mptcp_is_data_contiguous(ssk)) { > + ssk->sk_err = EBADMSG; > + tcp_set_state(ssk, TCP_CLOSE); > + subflow->reset_transient = 0; > + subflow->reset_reason = MPTCP_RST_EMIDDLEBOX; > + tcp_send_active_reset(ssk, GFP_ATOMIC); > while ((skb = skb_peek(&ssk->sk_receive_queue))) > sk_eat_skb(ssk, skb); > } > - ssk->sk_err = EBADMSG; > - tcp_set_state(ssk, TCP_CLOSE); > - subflow->reset_transient = 0; > - subflow->reset_reason = MPTCP_RST_EMIDDLEBOX; > - tcp_send_active_reset(ssk, GFP_ATOMIC); > WRITE_ONCE(subflow->data_avail, 0); > return true; > } > -- > 2.31.1 > > > -- Mat Martineau Intel
Mat Martineau <mathew.j.martineau@linux.intel.com> 于2021年9月28日周二 上午8:52写道： > > On Sun, 26 Sep 2021, Geliang Tang wrote: > > > This patch added a new member last_retrans_seq in mptcp_subflow_context > > to track the last retransmitting sequence number. > > > > Add a new helper named mptcp_is_data_contiguous() to check whether the > > data is contiguous on a subflow. > > > > When a bad checksum is detected and a single contiguous subflow is in use, > > don't send RST + MP_FAIL, send data_ack + MP_FAIL instead. > > > > Suggested-by: Paolo Abeni <pabeni@redhat.com> > > Signed-off-by: Geliang Tang <geliangtang@gmail.com> > > Hi Geliang - > > I know there's been a lot of churn in this part of the patch series, > hopefully we can simplify a little to allow us to merge the first step of > infinite mapping send/recv. Hi Mat, Paolo, Matt, I prefer to continue doing more iterations of this series instead of merging part of them first. There's still some work to do in it, but it's nearly finished. I'll send a v6 recently. And the infinite mapping support is the last issue assigned to me on GitHub. So I'm thinking about what should I do next. Could you give me some suggestions? Thanks, -Geliang > > In v3 and v4 reviews, I suggested tracking the subflow sequence number > like you do in this patch. After the discussion in the 2021-09-23 meeting, > proper tracking of contiguous data appeared even more complicated, so > Paolo had a suggestion to allow fallback in one simple-to-check case: Only > do infinite mapping fallback if there is a single subflow AND there have > been no retransmissions AND there have never been any MP_JOINs. > > That can be tracked with a "allow_infinite_fallback" bool in mptcp_sock, > which gets initialized to 'true' when the connection begins and is set to > 'false' on any retransmit or successful MP_JOIN. > > Paolo, is that an accurate summary? > > > It's important that this type of fallback only happens when it is > guaranteed that the stream is fully in-sequence, otherwise the > application's data gets corrupted. The above suggestion lets us merge > working infinite mapping code, and then figure out the more complicated > "fallback after retransmissions or join" logic in a separate patch series. > > > Thanks, > > Mat > > > > > --- > > net/mptcp/protocol.c | 6 ++++++ > > net/mptcp/protocol.h | 8 ++++++++ > > net/mptcp/subflow.c | 12 ++++++------ > > 3 files changed, 20 insertions(+), 6 deletions(-) > > > > diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c > > index f8ad049d6941..cf8cccfefb51 100644 > > --- a/net/mptcp/protocol.c > > +++ b/net/mptcp/protocol.c > > @@ -729,6 +729,9 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk) > > if (unlikely(subflow->disposable)) > > return; > > > > + if (!subflow->last_retrans_seq || mptcp_is_data_contiguous(ssk)) > > + subflow->last_retrans_seq = tcp_sk(ssk)->snd_una - 1; > > + > > ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf); > > sk_rbuf = READ_ONCE(sk->sk_rcvbuf); > > if (unlikely(ssk_rbuf > sk_rbuf)) > > @@ -2415,6 +2418,7 @@ static void mptcp_check_fastclose(struct mptcp_sock *msk) > > static void __mptcp_retrans(struct sock *sk) > > { > > struct mptcp_sock *msk = mptcp_sk(sk); > > + struct mptcp_subflow_context *subflow; > > struct mptcp_sendmsg_info info = {}; > > struct mptcp_data_frag *dfrag; > > size_t copied = 0; > > @@ -2464,6 +2468,8 @@ static void __mptcp_retrans(struct sock *sk) > > dfrag->already_sent = max(dfrag->already_sent, info.sent); > > tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, > > info.size_goal); > > + subflow = mptcp_subflow_ctx(ssk); > > + subflow->last_retrans_seq = tcp_sk(ssk)->snd_nxt; > > } > > > > release_sock(ssk); > > diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h > > index 7379ab580a7e..e090a9244f8b 100644 > > --- a/net/mptcp/protocol.h > > +++ b/net/mptcp/protocol.h > > @@ -416,6 +416,7 @@ struct mptcp_subflow_context { > > u32 map_data_len; > > __wsum map_data_csum; > > u32 map_csum_len; > > + u32 last_retrans_seq; > > u32 request_mptcp : 1, /* send MP_CAPABLE */ > > request_join : 1, /* send MP_JOIN */ > > request_bkup : 1, > > @@ -625,6 +626,13 @@ static inline bool mptcp_has_another_subflow(struct sock *ssk) > > return false; > > } > > > > +static inline bool mptcp_is_data_contiguous(struct sock *ssk) > > +{ > > + struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); > > + > > + return before(subflow->last_retrans_seq, tcp_sk(ssk)->snd_una); > > +} > > + > > void __init mptcp_proto_init(void); > > #if IS_ENABLED(CONFIG_MPTCP_IPV6) > > int __init mptcp_proto_v6_init(void); > > diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c > > index 6172f380dfb7..a8f46a48feb1 100644 > > --- a/net/mptcp/subflow.c > > +++ b/net/mptcp/subflow.c > > @@ -1166,15 +1166,15 @@ static bool subflow_check_data_avail(struct sock *ssk) > > fallback: > > /* RFC 8684 section 3.7. */ > > if (subflow->send_mp_fail) { > > - if (mptcp_has_another_subflow(ssk)) { > > + if (mptcp_has_another_subflow(ssk) || !mptcp_is_data_contiguous(ssk)) { > > + ssk->sk_err = EBADMSG; > > + tcp_set_state(ssk, TCP_CLOSE); > > + subflow->reset_transient = 0; > > + subflow->reset_reason = MPTCP_RST_EMIDDLEBOX; > > + tcp_send_active_reset(ssk, GFP_ATOMIC); > > while ((skb = skb_peek(&ssk->sk_receive_queue))) > > sk_eat_skb(ssk, skb); > > } > > - ssk->sk_err = EBADMSG; > > - tcp_set_state(ssk, TCP_CLOSE); > > - subflow->reset_transient = 0; > > - subflow->reset_reason = MPTCP_RST_EMIDDLEBOX; > > - tcp_send_active_reset(ssk, GFP_ATOMIC); > > WRITE_ONCE(subflow->data_avail, 0); > > return true; > > } > > -- > > 2.31.1 > > > > > > > > -- > Mat Martineau > Intel >
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index f8ad049d6941..cf8cccfefb51 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -729,6 +729,9 @@ void mptcp_data_ready(struct sock *sk, struct sock *ssk) if (unlikely(subflow->disposable)) return; + if (!subflow->last_retrans_seq || mptcp_is_data_contiguous(ssk)) + subflow->last_retrans_seq = tcp_sk(ssk)->snd_una - 1; + ssk_rbuf = READ_ONCE(ssk->sk_rcvbuf); sk_rbuf = READ_ONCE(sk->sk_rcvbuf); if (unlikely(ssk_rbuf > sk_rbuf)) @@ -2415,6 +2418,7 @@ static void mptcp_check_fastclose(struct mptcp_sock *msk) static void __mptcp_retrans(struct sock *sk) { struct mptcp_sock *msk = mptcp_sk(sk); + struct mptcp_subflow_context *subflow; struct mptcp_sendmsg_info info = {}; struct mptcp_data_frag *dfrag; size_t copied = 0; @@ -2464,6 +2468,8 @@ static void __mptcp_retrans(struct sock *sk) dfrag->already_sent = max(dfrag->already_sent, info.sent); tcp_push(ssk, 0, info.mss_now, tcp_sk(ssk)->nonagle, info.size_goal); + subflow = mptcp_subflow_ctx(ssk); + subflow->last_retrans_seq = tcp_sk(ssk)->snd_nxt; } release_sock(ssk); diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h index 7379ab580a7e..e090a9244f8b 100644 --- a/net/mptcp/protocol.h +++ b/net/mptcp/protocol.h @@ -416,6 +416,7 @@ struct mptcp_subflow_context { u32 map_data_len; __wsum map_data_csum; u32 map_csum_len; + u32 last_retrans_seq; u32 request_mptcp : 1, /* send MP_CAPABLE */ request_join : 1, /* send MP_JOIN */ request_bkup : 1, @@ -625,6 +626,13 @@ static inline bool mptcp_has_another_subflow(struct sock *ssk) return false; } +static inline bool mptcp_is_data_contiguous(struct sock *ssk) +{ + struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(ssk); + + return before(subflow->last_retrans_seq, tcp_sk(ssk)->snd_una); +} + void __init mptcp_proto_init(void); #if IS_ENABLED(CONFIG_MPTCP_IPV6) int __init mptcp_proto_v6_init(void); diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c index 6172f380dfb7..a8f46a48feb1 100644 --- a/net/mptcp/subflow.c +++ b/net/mptcp/subflow.c @@ -1166,15 +1166,15 @@ static bool subflow_check_data_avail(struct sock *ssk) fallback: /* RFC 8684 section 3.7. */ if (subflow->send_mp_fail) { - if (mptcp_has_another_subflow(ssk)) { + if (mptcp_has_another_subflow(ssk) || !mptcp_is_data_contiguous(ssk)) { + ssk->sk_err = EBADMSG; + tcp_set_state(ssk, TCP_CLOSE); + subflow->reset_transient = 0; + subflow->reset_reason = MPTCP_RST_EMIDDLEBOX; + tcp_send_active_reset(ssk, GFP_ATOMIC); while ((skb = skb_peek(&ssk->sk_receive_queue))) sk_eat_skb(ssk, skb); } - ssk->sk_err = EBADMSG; - tcp_set_state(ssk, TCP_CLOSE); - subflow->reset_transient = 0; - subflow->reset_reason = MPTCP_RST_EMIDDLEBOX; - tcp_send_active_reset(ssk, GFP_ATOMIC); WRITE_ONCE(subflow->data_avail, 0); return true; }
This patch added a new member last_retrans_seq in mptcp_subflow_context to track the last retransmitting sequence number. Add a new helper named mptcp_is_data_contiguous() to check whether the data is contiguous on a subflow. When a bad checksum is detected and a single contiguous subflow is in use, don't send RST + MP_FAIL, send data_ack + MP_FAIL instead. Suggested-by: Paolo Abeni <pabeni@redhat.com> Signed-off-by: Geliang Tang <geliangtang@gmail.com> --- net/mptcp/protocol.c | 6 ++++++ net/mptcp/protocol.h | 8 ++++++++ net/mptcp/subflow.c | 12 ++++++------ 3 files changed, 20 insertions(+), 6 deletions(-)