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mptcp: consolidate synack processing.

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Currently the MPTCP code uses 2 hooks to process syn-ack
packets, mptcp_rcv_synsent() and the sk_rx_dst_set()
callback.

We can drop the first, moving the relevant code into the
latter, reducing the hooking into the TCP code. This is
also needed by the next patch.

v1 -> v2:
 - use local tcp sock ptr instead of casting the sk variable
   several times - DaveM

Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paolo Abeni 2020-04-30 15:01:51 +02:00 committed by David S. Miller
parent 30724ccbfc
commit 263e1201a2
4 changed files with 24 additions and 29 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

1
include/net/mptcp.h
View file

@ -72,7 +72,6 @@ void mptcp_parse_option(const struct sk_buff *skb, const unsigned char *ptr,
int opsize, struct tcp_options_received *opt_rx);
bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
unsigned int *size, struct mptcp_out_options *opts);
void mptcp_rcv_synsent(struct sock *sk);
bool mptcp_synack_options(const struct request_sock *req, unsigned int *size,
struct mptcp_out_options *opts);
bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,

3
net/ipv4/tcp_input.c
View file

@ -5990,9 +5990,6 @@ static int tcp_rcv_synsent_state_process(struct sock *sk, struct sk_buff *skb,
tcp_sync_mss(sk, icsk->icsk_pmtu_cookie);
tcp_initialize_rcv_mss(sk);
if (sk_is_mptcp(sk))
mptcp_rcv_synsent(sk);
/* Remember, tcp_poll() does not lock socket!
* Change state from SYN-SENT only after copied_seq
* is initialized. */

22
net/mptcp/options.c
View file

@ -344,28 +344,6 @@ bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
return false;
}
void mptcp_rcv_synsent(struct sock *sk)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
struct tcp_sock *tp = tcp_sk(sk);
if (subflow->request_mptcp && tp->rx_opt.mptcp.mp_capable) {
subflow->mp_capable = 1;
subflow->can_ack = 1;
subflow->remote_key = tp->rx_opt.mptcp.sndr_key;
pr_debug("subflow=%p, remote_key=%llu", subflow,
subflow->remote_key);
} else if (subflow->request_join && tp->rx_opt.mptcp.mp_join) {
subflow->mp_join = 1;
subflow->thmac = tp->rx_opt.mptcp.thmac;
subflow->remote_nonce = tp->rx_opt.mptcp.nonce;
pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u", subflow,
subflow->thmac, subflow->remote_nonce);
} else if (subflow->request_mptcp) {
tcp_sk(sk)->is_mptcp = 0;
}
}
/* MP_JOIN client subflow must wait for 4th ack before sending any data:
* TCP can't schedule delack timer before the subflow is fully established.
* MPTCP uses the delack timer to do 3rd ack retransmissions

27
net/mptcp/subflow.c
View file

@ -222,6 +222,7 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
{
struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
struct sock *parent = subflow->conn;
struct tcp_sock *tp = tcp_sk(sk);
subflow->icsk_af_ops->sk_rx_dst_set(sk, skb);
@ -230,14 +231,35 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
parent->sk_state_change(parent);
}
if (subflow->conn_finished || !tcp_sk(sk)->is_mptcp)
/* be sure no special action on any packet other than syn-ack */
if (subflow->conn_finished)
return;
subflow->conn_finished = 1;
if (subflow->request_mptcp && tp->rx_opt.mptcp.mp_capable) {
subflow->mp_capable = 1;
subflow->can_ack = 1;
subflow->remote_key = tp->rx_opt.mptcp.sndr_key;
pr_debug("subflow=%p, remote_key=%llu", subflow,
subflow->remote_key);
} else if (subflow->request_join && tp->rx_opt.mptcp.mp_join) {
subflow->mp_join = 1;
subflow->thmac = tp->rx_opt.mptcp.thmac;
subflow->remote_nonce = tp->rx_opt.mptcp.nonce;
pr_debug("subflow=%p, thmac=%llu, remote_nonce=%u", subflow,
subflow->thmac, subflow->remote_nonce);
} else if (subflow->request_mptcp) {
tp->is_mptcp = 0;
}
if (!tp->is_mptcp)
return;
if (subflow->mp_capable) {
pr_debug("subflow=%p, remote_key=%llu", mptcp_subflow_ctx(sk),
subflow->remote_key);
mptcp_finish_connect(sk);
subflow->conn_finished = 1;
if (skb) {
pr_debug("synack seq=%u", TCP_SKB_CB(skb)->seq);
@ -264,7 +286,6 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
if (!mptcp_finish_join(sk))
goto do_reset;
subflow->conn_finished = 1;
MPTCP_INC_STATS(sock_net(sk), MPTCP_MIB_JOINSYNACKRX);
} else {
do_reset: