diff options
authorPaolo Abeni <pabeni@redhat.com>2020-05-15 19:22:15 +0200
committerDavid S. Miller <davem@davemloft.net>2020-05-15 12:30:13 -0700
commit90bf45134d55d626ae2713cac50cda10c6c8b0c2 (patch)
parentnet: phy: tja11xx: execute cable test on link up (diff)
mptcp: add new sock flag to deal with join subflows
MP_JOIN subflows must not land into the accept queue. Currently tcp_check_req() calls an mptcp specific helper to detect such scenario. Such helper leverages the subflow context to check for MP_JOIN subflows. We need to deal also with MP JOIN failures, even when the subflow context is not available due allocation failure. A possible solution would be changing the syn_recv_sock() signature to allow returning a more descriptive action/ error code and deal with that in tcp_check_req(). Since the above need is MPTCP specific, this patch instead uses a TCP request socket hole to add a MPTCP specific flag. Such flag is used by the MPTCP syn_recv_sock() to tell tcp_check_req() how to deal with the request socket. This change is a no-op for !MPTCP build, and makes the MPTCP code simpler. It allows also the next patch to deal correctly with MP JOIN failure. v1 -> v2: - be more conservative on drop_req initialization (Mat) RFC -> v1: - move the drop_req bit inside tcp_request_sock (Eric) Signed-off-by: Paolo Abeni <pabeni@redhat.com> Reviewed-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Reviewed-by: Christoph Paasch <cpaasch@apple.com> Signed-off-by: David S. Miller <davem@davemloft.net>
5 files changed, 17 insertions, 15 deletions
diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index e60db06ec28d..bf44e85d709d 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -120,6 +120,9 @@ struct tcp_request_sock {
u64 snt_synack; /* first SYNACK sent time */
bool tfo_listener;
bool is_mptcp;
+ bool drop_req;
u32 txhash;
u32 rcv_isn;
u32 snt_isn;
diff --git a/include/net/mptcp.h b/include/net/mptcp.h
index e60275659de6..c4a6ef4ba35b 100644
--- a/include/net/mptcp.h
+++ b/include/net/mptcp.h
@@ -68,6 +68,11 @@ static inline bool rsk_is_mptcp(const struct request_sock *req)
return tcp_rsk(req)->is_mptcp;
+static inline bool rsk_drop_req(const struct request_sock *req)
+ return tcp_rsk(req)->is_mptcp && tcp_rsk(req)->drop_req;
void mptcp_space(const struct sock *ssk, int *space, int *full_space);
bool mptcp_syn_options(struct sock *sk, const struct sk_buff *skb,
unsigned int *size, struct mptcp_out_options *opts);
@@ -121,8 +126,6 @@ static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
skb_ext_find(from, SKB_EXT_MPTCP));
-bool mptcp_sk_is_subflow(const struct sock *sk);
void mptcp_seq_show(struct seq_file *seq);
@@ -140,6 +143,11 @@ static inline bool rsk_is_mptcp(const struct request_sock *req)
return false;
+static inline bool rsk_drop_req(const struct request_sock *req)
+ return false;
static inline void mptcp_parse_option(const struct sk_buff *skb,
const unsigned char *ptr, int opsize,
struct tcp_options_received *opt_rx)
@@ -190,11 +198,6 @@ static inline bool mptcp_skb_can_collapse(const struct sk_buff *to,
return true;
-static inline bool mptcp_sk_is_subflow(const struct sock *sk)
- return false;
static inline void mptcp_space(const struct sock *ssk, int *s, int *fs) { }
static inline void mptcp_seq_show(struct seq_file *seq) { }
#endif /* CONFIG_MPTCP */
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c
index 7e40322cc5ec..495dda2449fe 100644
--- a/net/ipv4/tcp_minisocks.c
+++ b/net/ipv4/tcp_minisocks.c
@@ -774,7 +774,7 @@ struct sock *tcp_check_req(struct sock *sk, struct sk_buff *skb,
if (!child)
goto listen_overflow;
- if (own_req && sk_is_mptcp(child) && mptcp_sk_is_subflow(child)) {
+ if (own_req && rsk_drop_req(req)) {
reqsk_queue_removed(&inet_csk(sk)->icsk_accept_queue, req);
inet_csk_reqsk_queue_drop_and_put(sk, req);
return child;
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index e1f23016ed3f..a61e60e94137 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1638,13 +1638,6 @@ bool mptcp_finish_join(struct sock *sk)
return ret;
-bool mptcp_sk_is_subflow(const struct sock *sk)
- struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
- return subflow->mp_join == 1;
static bool mptcp_memory_free(const struct sock *sk, int wake)
struct mptcp_sock *msk = mptcp_sk(sk);
diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index 009d5c478062..5e03ed8ae899 100644
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -470,6 +470,8 @@ create_child:
if (child && *own_req) {
struct mptcp_subflow_context *ctx = mptcp_subflow_ctx(child);
+ tcp_rsk(req)->drop_req = false;
/* we need to fallback on ctx allocation failure and on pre-reqs
* checking above. In the latter scenario we additionally need
* to reset the context to non MPTCP status.
@@ -512,6 +514,7 @@ create_child:
goto close_child;
+ tcp_rsk(req)->drop_req = true;