Re: [MPTCP] [PATCH] Revert tcp_skb_cb to it's original size and cleanup main TCP Rx code from MPTCP specific code.

This patch returns tcp_skb_cb to it's original size. It also refactors MPTCP code so that there are no MPTCP checks in the main Rx pathi, no performance overheads such as cpu prodiction issues. tcp_v4_rcv() and tcp_v4_do_rcv() do not have any MPTCP specific checks any more, niether does tcp_ack(). On the Rx path MPTCP options are not parsed till the data is being pushed up to the meta socket (mptcp_data_ready). on the Tx side there is one check to add MPTCP specific options but that's it, that should not be that bad as for regular TCP it is a simple check, but it would be good to remove it.. I have tested the changes with ndiffports set to 2, so join works. I have also tested accessing multipath-tcp.org and downloading files from there and also ran the speed test. The Bad: The error cases still have MPTCP checks but that should be OK as they are error cases. I had to use a special marker 0xFEE1DEAD for indicate a special case. I had to introdue a new socket specfic function. IPv6 has not been changed yet. I am sure I have missed some corner cases and more testing will reveal more issues but we just have to fix them. I would like to hear comments from the list and if this direction seems reasonable we can take this as the starting point, port it to latest Linux and share the design with the mainstream folks.

Signed-off-by: Rao Shoaib <rao.shoaib(a)oracle.com&gt; --- include/linux/skbuff.h | 8 ++- include/net/mptcp.h | 21 +++--- include/net/mptcp_v4.h | 1 + include/net/sock.h | 12 +++- include/net/tcp.h | 23 +++---- net/ipv4/af_inet.c | 4 ++ net/ipv4/tcp_input.c | 37 ++-------- net/ipv4/tcp_ipv4.c | 135 +++++++++++++++++++++++-------------- net/ipv4/tcp_output.c | 1 + net/ipv6/af_inet6.c | 4 ++ net/ipv6/tcp_ipv6.c | 4 -- net/mptcp/mptcp_ctrl.c | 21 ++++++ net/mptcp/mptcp_input.c | 131 ++++++++++++++++++++++++++++-------- net/mptcp/mptcp_ipv4.c | 35 +--------- net/mptcp/mptcp_ipv6.c | 4 +- net/mptcp/mptcp_output.c | 160 +++++++++++++++++--------------------------- net/mptcp/mptcp_redundant.c | 6 +- net/mptcp/mptcp_rr.c | 4 +- net/mptcp/mptcp_sched.c | 10 +-- 19 files changed, 335 insertions(+), 286 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index f66cd5e..348cbc1 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -532,7 +532,13 @@ struct sk_buff { struct rb_node rbnode; /* used in netem & tcp stack */ }; struct sock *sk; - struct net_device *dev; + union { + struct net_device *dev; + struct { + __u8 mptcp_flags; + __u8 mptcp_dss_off; + }; + };

diff --git a/include/net/tcp.h b/include/net/tcp.h index 655ecd4..cbe8ef2 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -47,6 +47,9 @@ #include <linux/seq_file.h> #include <linux/memcontrol.h> +typedef int (* process_unclaimed)(struct sock *sk, struct sk_buff *skb); +extern process_unclaimed tcp_process_unclaimed; + extern struct inet_hashinfo tcp_hashinfo; extern struct percpu_counter tcp_orphan_count; @@ -581,6 +584,7 @@ struct sock *tcp_v4_syn_recv_sock(struct sock *sk, struct sk_buff *skb, struct request_sock *req, struct dst_entry *dst); int tcp_v4_do_rcv(struct sock *sk, struct sk_buff *skb); + int tcp_v4_connect(struct sock *sk, struct sockaddr *uaddr, int addr_len); int tcp_connect(struct sock *sk); struct sk_buff *tcp_make_synack(struct sock *sk, struct dst_entry *dst, @@ -842,11 +846,6 @@ struct tcp_skb_cb { __u32 tcp_gso_segs; }; -#ifdef CONFIG_MPTCP - __u8 mptcp_flags; /* flags for the MPTCP layer */ - __u8 dss_off; /* Number of 4-byte words until - * seq-number */ -#endif __u8 tcp_flags; /* TCP header flags. (tcp[13]) */ __u8 sacked; /* State flags for SACK/FACK. */ @@ -859,9 +858,13 @@ struct tcp_skb_cb { #define TCPCB_RETRANS (TCPCB_SACKED_RETRANS|TCPCB_EVER_RETRANS| \ TCPCB_REPAIRED) - __u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */ + __u8 ip_dsfield; /* IPv4 tos or IPv6 dsfield */ /* 1 byte hole */ - __u32 ack_seq; /* Sequence number ACK'd */ + union { + __u32 ack_seq; /* Sequence number ACK'd */ + __u32 mptcp_data_seq;

+ __u32 mptcp_path_mask; + };

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index 73480b9..1e7827f 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -356,6 +356,10 @@ lookup_protocol: sk->sk_destruct = inet_sock_destruct; sk->sk_protocol = protocol; sk->sk_backlog_rcv = sk->sk_prot->backlog_rcv; + sk->sk_prequeue = sk->sk_prot->prequeue; + if (sk->sk_prequeue == NULL) { + sk->sk_prequeue = sk_prequeue; + }