mptcp: add the outgoing MP_PRIO support

This patch added the outgoing MP_PRIO logic:

In mptcp_pm_nl_mp_prio_send_ack, find the related subflow and subsocket
according to the input parameter addr. Save the input priority value to
suflow's backup, then set subflow's send_mp_prio flag to true, and save
the input priority value to suflow's request_bkup. Finally, send out a
pure ACK on the related subsocket.

In mptcp_established_options_mp_prio, check whether the subflow's
send_mp_prio is set. If it is, this is the packet for sending MP_PRIO.
So save subflow->request_bkup value to mptcp_out_options's backup, and
change the option type to OPTION_MPTCP_PRIO.

In mptcp_write_options, clear the send_mp_prio flag and send out the
MP_PRIO suboption with mptcp_out_options's backup value.

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index e0d21c0..ef50a86 100644 (file)
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -679,6 +679,28 @@ static bool mptcp_established_options_rm_addr(struct sock *sk,
        return true;
 }
 
+static bool mptcp_established_options_mp_prio(struct sock *sk,
+                                             unsigned int *size,
+                                             unsigned int remaining,
+                                             struct mptcp_out_options *opts)
+{
+       struct mptcp_subflow_context *subflow = mptcp_subflow_ctx(sk);
+
+       if (!subflow->send_mp_prio)
+               return false;
+
+       if (remaining < TCPOLEN_MPTCP_PRIO)
+               return false;
+
+       *size = TCPOLEN_MPTCP_PRIO;
+       opts->suboptions |= OPTION_MPTCP_PRIO;
+       opts->backup = subflow->request_bkup;
+
+       pr_debug("prio=%d", opts->backup);
+
+       return true;
+}
+
 bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
                               unsigned int *size, unsigned int remaining,
                               struct mptcp_out_options *opts)
@@ -721,6 +743,12 @@ bool mptcp_established_options(struct sock *sk, struct sk_buff *skb,
                ret = true;
        }
 
+       if (mptcp_established_options_mp_prio(sk, &opt_size, remaining, opts)) {
+               *size += opt_size;
+               remaining -= opt_size;
+               ret = true;
+       }
+
        return ret;
 }
 
@@ -1168,6 +1196,18 @@ mp_capable_done:
                                      0, opts->rm_id);
        }
 
+       if (OPTION_MPTCP_PRIO & opts->suboptions) {
+               const struct sock *ssk = (const struct sock *)tp;
+               struct mptcp_subflow_context *subflow;
+
+               subflow = mptcp_subflow_ctx(ssk);
+               subflow->send_mp_prio = 0;
+
+               *ptr++ = mptcp_option(MPTCPOPT_MP_PRIO,
+                                     TCPOLEN_MPTCP_PRIO,
+                                     opts->backup, TCPOPT_NOP);
+       }
+
        if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) {
                *ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
                                      TCPOLEN_MPTCP_MPJ_SYN,

diff --git a/net/mptcp/pm_netlink.c b/net/mptcp/pm_netlink.c
index 7fe7be4..bf0d13c 100644 (file)
--- a/net/mptcp/pm_netlink.c
+++ b/net/mptcp/pm_netlink.c
@@ -442,6 +442,39 @@ void mptcp_pm_nl_add_addr_send_ack(struct mptcp_sock *msk)
        }
 }
 
+int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
+                                struct mptcp_addr_info *addr,
+                                u8 bkup)
+{
+       struct mptcp_subflow_context *subflow;
+
+       pr_debug("bkup=%d", bkup);
+
+       mptcp_for_each_subflow(msk, subflow) {
+               struct sock *ssk = mptcp_subflow_tcp_sock(subflow);
+               struct mptcp_addr_info local;
+
+               local_address((struct sock_common *)ssk, &local);
+               if (!addresses_equal(&local, addr, addr->port))
+                       continue;
+
+               subflow->backup = bkup;
+               subflow->send_mp_prio = 1;
+               subflow->request_bkup = bkup;
+
+               spin_unlock_bh(&msk->pm.lock);
+               pr_debug("send ack for mp_prio");
+               lock_sock(ssk);
+               tcp_send_ack(ssk);
+               release_sock(ssk);
+               spin_lock_bh(&msk->pm.lock);
+
+               return 0;
+       }
+
+       return -EINVAL;
+}
+
 void mptcp_pm_nl_rm_addr_received(struct mptcp_sock *msk)
 {
        struct mptcp_subflow_context *subflow, *tmp;

diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index d67de79..21763e0 100644 (file)
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -24,6 +24,7 @@
 #define OPTION_MPTCP_ADD_ADDR6 BIT(7)
 #define OPTION_MPTCP_RM_ADDR   BIT(8)
 #define OPTION_MPTCP_FASTCLOSE BIT(9)
+#define OPTION_MPTCP_PRIO      BIT(10)
 
 /* MPTCP option subtypes */
 #define MPTCPOPT_MP_CAPABLE    0
@@ -59,6 +60,7 @@
 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT      24
 #define TCPOLEN_MPTCP_PORT_LEN         4
 #define TCPOLEN_MPTCP_RM_ADDR_BASE     4
+#define TCPOLEN_MPTCP_PRIO             4
 #define TCPOLEN_MPTCP_FASTCLOSE                12
 
 /* MPTCP MP_JOIN flags */
@@ -396,6 +398,7 @@ struct mptcp_subflow_context {
                map_valid : 1,
                mpc_map : 1,
                backup : 1,
+               send_mp_prio : 1,
                rx_eof : 1,
                can_ack : 1,        /* only after processing the remote a key */
                disposable : 1;     /* ctx can be free at ulp release time */
@@ -550,6 +553,9 @@ void mptcp_pm_add_addr_received(struct mptcp_sock *msk,
                                const struct mptcp_addr_info *addr);
 void mptcp_pm_add_addr_send_ack(struct mptcp_sock *msk);
 void mptcp_pm_rm_addr_received(struct mptcp_sock *msk, u8 rm_id);
+int mptcp_pm_nl_mp_prio_send_ack(struct mptcp_sock *msk,
+                                struct mptcp_addr_info *addr,
+                                u8 bkup);
 void mptcp_pm_free_anno_list(struct mptcp_sock *msk);
 struct mptcp_pm_add_entry *
 mptcp_pm_del_add_timer(struct mptcp_sock *msk,