[PATCH net-next 1/3] mptcp: add MP_PRIO suboption handling

[Geliang Tang]

Add handling for sending and receiving MP_PRIO suboption.

Signed-off-by: Geliang Tang <geliangtang@xxxxxxxxx>
---
 net/mptcp/options.c  | 14 ++++++++++++++
 net/mptcp/protocol.h |  5 +++++
 2 files changed, 19 insertions(+)

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index 490b92534afc..cc3039f0ac43 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -280,6 +280,14 @@ static void mptcp_parse_option(const struct sk_buff *skb,
 		pr_debug("RM_ADDR: id=%d", mp_opt->rm_id);
 		break;
 
+	case MPTCPOPT_MP_PRIO:
+		if (opsize != TCPOLEN_MPTCP_PRIO)
+			break;
+
+		mp_opt->backup = (*ptr++) & MPTCP_PRIO_BACKUP;
+		pr_debug("MP_PRIO: backup=%d", mp_opt->backup);
+		break;
+
 	default:
 		break;
 	}
@@ -961,6 +969,12 @@ void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts)
 				      0, opts->rm_id);
 	}
 
+	if (OPTION_MPTCP_PRIO & opts->suboptions) {
+		*ptr++ = mptcp_option(MPTCPOPT_MP_PRIO,
+				      TCPOLEN_MPTCP_PRIO,
+				      opts->backup, 0);
+	}
+
 	if (OPTION_MPTCP_MPJ_SYN & opts->suboptions) {
 		*ptr++ = mptcp_option(MPTCPOPT_MP_JOIN,
 				      TCPOLEN_MPTCP_MPJ_SYN,
diff --git a/net/mptcp/protocol.h b/net/mptcp/protocol.h
index db56535dfc29..623c9a1c4343 100644
--- a/net/mptcp/protocol.h
+++ b/net/mptcp/protocol.h
@@ -23,6 +23,7 @@
 #define OPTION_MPTCP_ADD_ADDR	BIT(6)
 #define OPTION_MPTCP_ADD_ADDR6	BIT(7)
 #define OPTION_MPTCP_RM_ADDR	BIT(8)
+#define OPTION_MPTCP_PRIO	BIT(9)
 
 /* MPTCP option subtypes */
 #define MPTCPOPT_MP_CAPABLE	0
@@ -58,6 +59,7 @@
 #define TCPOLEN_MPTCP_ADD_ADDR6_BASE_PORT	22
 #define TCPOLEN_MPTCP_PORT_LEN		2
 #define TCPOLEN_MPTCP_RM_ADDR_BASE	4
+#define TCPOLEN_MPTCP_PRIO		3
 
 /* MPTCP MP_JOIN flags */
 #define MPTCPOPT_BACKUP		BIT(0)
@@ -84,6 +86,9 @@
 #define MPTCP_ADDR_IPVERSION_4	4
 #define MPTCP_ADDR_IPVERSION_6	6
 
+/* MPTCP MP_PRIO flags */
+#define MPTCP_PRIO_BACKUP	BIT(0)
+
 /* MPTCP socket flags */
 #define MPTCP_DATA_READY	0
 #define MPTCP_SEND_SPACE	1
-- 
2.17.1