[RFC,mptcp-next,v13,5/7] mptcp: add subflow_v(4,6)_send_synack()

Commit Message

Dmytro Shytyi Oct. 1, 2022, 3:15 a.m. UTC

In this patch we add skb to the msk, dequeue it from sk, remove TSs and
do skb mapping.

Signed-off-by: Dmytro Shytyi <[e-mail]>
---
 net/mptcp/fastopen.c | 55 ++++++++++++++++++++++++++++++++++++++++++++
 net/mptcp/protocol.c |  2 +-
 net/mptcp/protocol.h |  3 +++
 net/mptcp/subflow.c  | 42 +++++++++++++++++++++++++++++++++
 4 files changed, 101 insertions(+), 1 deletion(-)

Patch

diff --git a/net/mptcp/fastopen.c b/net/mptcp/fastopen.c
index dca736c61815..0193ed455a73 100644
--- a/net/mptcp/fastopen.c
+++ b/net/mptcp/fastopen.c
@@ -4,6 +4,61 @@ 
 
 #include "protocol.h"
 
+struct mptcp_skb_cb {
+	u64 map_seq;
+	u64 end_seq;
+	u32 offset;
+	u8  has_rxtstamp:1;
+};
+
+#define MPTCP_SKB_CB(__skb)	((struct mptcp_skb_cb *)&((__skb)->cb[0]))
+
+void subflow_fastopen_send_synack_set_params(struct mptcp_subflow_context *subflow,
+					     struct request_sock *treq)
+{
+	struct tcp_request_sock *tcp_r_sock = tcp_rsk(treq);
+	struct sock *ssk = subflow->tcp_sock;
+	struct sock *sk = subflow->conn;
+	struct mptcp_sock *msk;
+	struct sk_buff *skb;
+	struct tcp_sock *tp;
+	u32 offset;
+
+	msk = mptcp_sk(sk);
+	tp = tcp_sk(ssk);
+
+	/* mark subflow/msk as "mptfo" */
+	msk->is_mptfo = 1;
+
+	skb = skb_peek(&ssk->sk_receive_queue);
+
+	/* dequeue the skb from sk receive queue */
+	__skb_unlink(skb, &ssk->sk_receive_queue);
+	skb_ext_reset(skb);
+	skb_orphan(skb);
+
+	/* set the skb mapping */
+	tp->copied_seq += tp->rcv_nxt - tcp_r_sock->rcv_isn - 1;
+	subflow->map_seq = mptcp_subflow_get_mapped_dsn(subflow);
+	subflow->ssn_offset = tp->copied_seq - 1;
+
+	/* innitialize MPTCP_CB */
+	offset = tp->copied_seq - TCP_SKB_CB(skb)->seq;
+	MPTCP_SKB_CB(skb)->map_seq = mptcp_subflow_get_mapped_dsn(subflow);
+	MPTCP_SKB_CB(skb)->end_seq = msk->ack_seq;
+	MPTCP_SKB_CB(skb)->offset = offset;
+	MPTCP_SKB_CB(skb)->has_rxtstamp = TCP_SKB_CB(skb)->has_rxtstamp;
+
+	mptcp_data_lock(sk);
+
+	mptcp_set_owner_r(skb, sk);
+	__skb_queue_tail(&msk->receive_queue, skb);
+
+	(sk)->sk_data_ready(sk);
+
+	mptcp_data_unlock(sk);
+}
+
 void __mptcp_pre_connect(struct mptcp_sock *msk, struct sock *ssk,
 			 struct msghdr *msg, size_t size)
 {
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 0d8602ddf146..7f6de5028778 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -200,7 +200,7 @@  static void mptcp_rfree(struct sk_buff *skb)
 	mptcp_rmem_uncharge(sk, len);
 }
 
-static void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk)
+void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk)
 {
 	skb_orphan(skb);
 	skb->sk = sk;
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index c356c993597c..4d550241dbb2 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -846,6 +846,9 @@  void __mptcp_pre_connect(struct mptcp_sock *msk, struct sock *ssk,
 			 struct msghdr *msg, size_t len);
 void mptcp_gen_msk_ackseq_fastopen(struct mptcp_sock *msk, struct mptcp_subflow_context *subflow,
 				   struct mptcp_options_received mp_opt);
+void mptcp_set_owner_r(struct sk_buff *skb, struct sock *sk);
+void subflow_fastopen_send_synack_set_params(struct mptcp_subflow_context *subflow,
+					     struct request_sock *req);
 // Fast Open Mechanism functions end
 
 static inline bool mptcp_pm_should_add_signal(struct mptcp_sock *msk)
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 07dd23d0fe04..3c1f971f1d9e 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -307,6 +307,46 @@  static struct dst_entry *subflow_v4_route_req(const struct sock *sk,
 	return NULL;
 }
 
+static int subflow_v4_send_synack(const struct sock *sk, struct dst_entry *dst,
+				  struct flowi *fl,
+				  struct request_sock *req,
+				  struct tcp_fastopen_cookie *foc,
+				  enum tcp_synack_type synack_type,
+				  struct sk_buff *syn_skb)
+{
+	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+	struct inet_request_sock *ireq = inet_rsk(req);
+
+	/* clear tstamp_ok, as needed depending on cookie */
+	if (foc && foc->len > -1)
+		ireq->tstamp_ok = 0;
+
+	if (synack_type == TCP_SYNACK_FASTOPEN)
+		subflow_fastopen_send_synack_set_params(subflow, req);
+
+	return tcp_request_sock_ipv4_ops.send_synack(sk, dst, fl, req, foc, synack_type, syn_skb);
+}
+
+static int subflow_v6_send_synack(const struct sock *sk, struct dst_entry *dst,
+				  struct flowi *fl,
+				  struct request_sock *req,
+				  struct tcp_fastopen_cookie *foc,
+				  enum tcp_synack_type synack_type,
+				  struct sk_buff *syn_skb)
+{
+	struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+	struct inet_request_sock *ireq = inet_rsk(req);
+
+	/* clear tstamp_ok, as needed depending on cookie */
+	if (foc && foc->len > -1)
+		ireq->tstamp_ok = 0;
+
+	if (synack_type == TCP_SYNACK_FASTOPEN)
+		subflow_fastopen_send_synack_set_params(subflow, req);
+
+	return tcp_request_sock_ipv6_ops.send_synack(sk, dst, fl, req, foc, synack_type, syn_skb);
+}
+
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 static struct dst_entry *subflow_v6_route_req(const struct sock *sk,
 					      struct sk_buff *skb,
@@ -1920,6 +1960,7 @@  void __init mptcp_subflow_init(void)
 
 	subflow_request_sock_ipv4_ops = tcp_request_sock_ipv4_ops;
 	subflow_request_sock_ipv4_ops.route_req = subflow_v4_route_req;
+	subflow_request_sock_ipv4_ops.send_synack = subflow_v4_send_synack;
 
 	subflow_specific = ipv4_specific;
 	subflow_specific.conn_request = subflow_v4_conn_request;
@@ -1933,6 +1974,7 @@  void __init mptcp_subflow_init(void)
 #if IS_ENABLED(CONFIG_MPTCP_IPV6)
 	subflow_request_sock_ipv6_ops = tcp_request_sock_ipv6_ops;
 	subflow_request_sock_ipv6_ops.route_req = subflow_v6_route_req;
+	subflow_request_sock_ipv6_ops.send_synack = subflow_v6_send_synack;
 
 	subflow_v6_specific = ipv6_specific;
 	subflow_v6_specific.conn_request = subflow_v6_conn_request;