mptcp: better binary layout for mptcp_options_received

This change reorder the mptcp_options_received fields
to shrink the structure a bit and to ensure the most
frequently used fields are all in the first cacheline.

Sub-opt specific flags are moved out of the suboptions area,
and we must now explicitly set them when the relevant
suboption is parsed.

There is a notable exception: 'csum_reqd' is used by both DSS
and MPC suboptions, and keeping such field in the suboptions
flag area will simplfy the next patch.

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

net/mptcp/options.c

@@ -83,8 +83,7 @@ static void mptcp_parse_option(const struct sk_buff *skb,
 		if (flags & MPTCP_CAP_CHECKSUM_REQD)
 			mp_opt->csum_reqd = 1;
 
-		if (flags & MPTCP_CAP_DENY_JOIN_ID0)
-			mp_opt->deny_join_id0 = 1;
+		mp_opt->deny_join_id0 = !!(flags & MPTCP_CAP_DENY_JOIN_ID0);
 
 		mp_opt->mp_capable = 1;
 		if (opsize >= TCPOLEN_MPTCP_MPC_SYNACK) {
@@ -262,6 +261,8 @@ static void mptcp_parse_option(const struct sk_buff *skb,
 
 		mp_opt->add_addr = 1;
 		mp_opt->addr.id = *ptr++;
+		mp_opt->addr.port = 0;
+		mp_opt->ahmac = 0;
 		if (mp_opt->addr.family == AF_INET) {
 			memcpy((u8 *)&mp_opt->addr.addr.s_addr, (u8 *)ptr, 4);
 			ptr += 4;
@@ -363,15 +364,12 @@ void mptcp_get_options(const struct sock *sk,
 	mp_opt->mp_capable = 0;
 	mp_opt->mp_join = 0;
 	mp_opt->add_addr = 0;
-	mp_opt->ahmac = 0;
 	mp_opt->fastclose = 0;
-	mp_opt->addr.port = 0;
 	mp_opt->rm_addr = 0;
 	mp_opt->dss = 0;
 	mp_opt->mp_prio = 0;
 	mp_opt->reset = 0;
 	mp_opt->csum_reqd = 0;
-	mp_opt->deny_join_id0 = 0;
 	mp_opt->mp_fail = 0;
 
 	length = (th->doff * 4) - sizeof(struct tcphdr);

net/mptcp/protocol.h

@@ -140,28 +140,28 @@ struct mptcp_options_received {
 		add_addr : 1,
 		rm_addr : 1,
 		mp_prio : 1,
-		mp_fail : 1,
-		echo : 1,
 		csum_reqd : 1,
-		backup : 1,
-		deny_join_id0 : 1;
+		mp_fail : 1;
 	u32	token;
 	u32	nonce;
-	u64	thmac;
-	u8	hmac[MPTCPOPT_HMAC_LEN];
-	u8	join_id;
-	u8	use_map:1,
+	u16	use_map:1,
 		dsn64:1,
 		data_fin:1,
 		use_ack:1,
 		ack64:1,
 		mpc_map:1,
+		reset_reason:4,
+		reset_transient:1,
+		echo:1,
+		backup:1,
+		deny_join_id0:1,
 		__unused:2;
+	u8	join_id;
+	u64	thmac;
+	u8	hmac[MPTCPOPT_HMAC_LEN];
 	struct mptcp_addr_info addr;
 	struct mptcp_rm_list rm_list;
 	u64	ahmac;
-	u8	reset_reason:4;
-	u8	reset_transient:1;
 	u64	fail_seq;
 };