[PATCH net-next 2/3] mptcp: add MP_FAIL suboption handling

[Geliang Tang <geliangtang@gmail.com>]

Add handling for sending and receiving MP_FAIL suboption.

Signed-off-by: Geliang Tang <geliangtang@gmail.com>
---
 net/mptcp/options.c  | 18 ++++++++++++++++++
 net/mptcp/protocol.h |  2 ++
 2 files changed, 20 insertions(+)

diff --git a/net/mptcp/options.c b/net/mptcp/options.c
index cc3039f0ac43..82b3d7c566b4 100644
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -288,6 +288,15 @@ static void mptcp_parse_option(const struct sk_buff *skb,
 		pr_debug("MP_PRIO: backup=%d", mp_opt->backup);
 		break;
 
+	case MPTCPOPT_MP_FAIL:
+		if (opsize != TCPOLEN_MPTCP_FAIL)
+			break;
+
+		ptr += 2;
+		mp_opt->data_seq = get_unaligned_be64(ptr);
+		pr_debug("MP_FAIL: data_seq=%lld", mp_opt->data_seq);
+		break;
+
 	default:
 		break;
 	}
@@ -975,6 +984,15 @@ void mptcp_write_options(__be32 *ptr, struct mptcp_out_options *opts)
 				      opts->backup, 0);
 	}
 
+	if (OPTION_MPTCP_FAIL & opts->suboptions) {
+		struct mptcp_ext *mpext = &opts->ext_copy;
+
+		*ptr++ = mptcp_option(MPTCPOPT_MP_FAIL,
+				      TCPOLEN_MPTCP_FAIL,
+				      0, 0);
+		put_unaligned_be64(mpext->data_seq, ptr);
+	}
+
 	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 623c9a1c4343..e6ae0a73716b 100644
--- 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_PRIO	BIT(9)
+#define OPTION_MPTCP_FAIL	BIT(10)
 
 /* MPTCP option subtypes */
 #define MPTCPOPT_MP_CAPABLE	0
@@ -60,6 +61,7 @@
 #define TCPOLEN_MPTCP_PORT_LEN		2
 #define TCPOLEN_MPTCP_RM_ADDR_BASE	4
 #define TCPOLEN_MPTCP_PRIO		3
+#define TCPOLEN_MPTCP_FAIL		12
 
 /* MPTCP MP_JOIN flags */
 #define MPTCPOPT_BACKUP		BIT(0)
-- 
2.17.1