mptcp: add csum_reqd in mptcp_options_received

This patch added a new flag csum_reqd in struct mptcp_options_received, if
the flag MPTCP_CAP_CHECKSUM_REQD is set in the receiving MP_CAPABLE
suboption, set this flag.

In mptcp_sk_clone and subflow_finish_connect, if the csum_reqd flag is set,
enable the msk->csum_enabled flag.

Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index ae69059..2e25515 100644 (file)
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -71,11 +71,9 @@ static void mptcp_parse_option(const struct sk_buff *skb,
                 * "If a checksum is not present when its use has been
                 * negotiated, the receiver MUST close the subflow with a RST as
                 * it is considered broken."
-                *
-                * We don't implement DSS checksum - fall back to TCP.
                 */
                if (flags & MPTCP_CAP_CHECKSUM_REQD)
-                       break;
+                       mp_opt->csum_reqd = 1;
 
                mp_opt->mp_capable = 1;
                if (opsize >= TCPOLEN_MPTCP_MPC_SYNACK) {
@@ -327,6 +325,8 @@ void mptcp_get_options(const struct sock *sk,
                       const struct sk_buff *skb,
                       struct mptcp_options_received *mp_opt)
 {
+       struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+       struct mptcp_sock *msk = mptcp_sk(subflow->conn);
        const struct tcphdr *th = tcp_hdr(skb);
        const unsigned char *ptr;
        int length;
@@ -342,6 +342,7 @@ void mptcp_get_options(const struct sock *sk,
        mp_opt->dss = 0;
        mp_opt->mp_prio = 0;
        mp_opt->reset = 0;
+       mp_opt->csum_reqd = READ_ONCE(msk->csum_enabled);
 
        length = (th->doff * 4) - sizeof(struct tcphdr);
        ptr = (const unsigned char *)(th + 1);

diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index f0da067..b6e5c09 100644 (file)
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2810,6 +2810,8 @@ struct sock *mptcp_sk_clone(const struct sock *sk,
        msk->token = subflow_req->token;
        msk->subflow = NULL;
        WRITE_ONCE(msk->fully_established, false);
+       if (mp_opt->csum_reqd)
+               WRITE_ONCE(msk->csum_enabled, true);
 
        msk->write_seq = subflow_req->idsn + 1;
        msk->snd_nxt = msk->write_seq;

diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index a7ed0b8..66e5063 100644 (file)
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -133,6 +133,7 @@ struct mptcp_options_received {
                rm_addr : 1,
                mp_prio : 1,
                echo : 1,
+               csum_reqd : 1,
                backup : 1;
        u32     token;
        u32     nonce;

diff --git a/net/mptcp/subflow.c b/net/mptcp/subflow.c
index aa6b307..9b82ce6 100644 (file)
--- a/net/mptcp/subflow.c
+++ b/net/mptcp/subflow.c
@@ -405,6 +405,8 @@ static void subflow_finish_connect(struct sock *sk, const struct sk_buff *skb)
                        goto fallback;
                }
 
+               if (mp_opt.csum_reqd)
+                       WRITE_ONCE(mptcp_sk(parent)->csum_enabled, true);
                subflow->mp_capable = 1;
                subflow->can_ack = 1;
                subflow->remote_key = mp_opt.sndr_key;