[PATCH net-next 0/7] mptcp: Miscellaneous changes for 5.18

@@ -1264,10 +1264,10 @@ static u16 mptcp_make_csum(const struct mptcp_ext *mpext)
 void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
 			 struct mptcp_out_options *opts)
 {
-	if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) {
-		const struct sock *ssk = (const struct sock *)tp;
-		struct mptcp_subflow_context *subflow;
+	const struct sock *ssk = (const struct sock *)tp;
+	struct mptcp_subflow_context *subflow;
 
+	if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) {
 		subflow = mptcp_subflow_ctx(ssk);
 		subflow->send_mp_fail = 0;
 

@@ -1489,9 +1489,6 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
 	}
 
 	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;
 

@@ -336,6 +336,8 @@ static void mptcp_parse_option(const struct sk_buff *skb,
 		flags = *ptr++;
 		mp_opt->reset_transient = flags & MPTCP_RST_TRANSIENT;
 		mp_opt->reset_reason = *ptr;
+		pr_debug("MP_RST: transient=%u reason=%u",
+			 mp_opt->reset_transient, mp_opt->reset_reason);
 		break;
 
 	case MPTCPOPT_MP_FAIL:

@@ -1267,17 +1267,6 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
 	const struct sock *ssk = (const struct sock *)tp;
 	struct mptcp_subflow_context *subflow;
 
-	if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) {
-		subflow = mptcp_subflow_ctx(ssk);
-		subflow->send_mp_fail = 0;
-
-		*ptr++ = mptcp_option(MPTCPOPT_MP_FAIL,
-				      TCPOLEN_MPTCP_FAIL,
-				      0, 0);
-		put_unaligned_be64(opts->fail_seq, ptr);
-		ptr += 2;
-	}
-
 	/* DSS, MPC, MPJ, ADD_ADDR, FASTCLOSE and RST are mutually exclusive,
 	 * see mptcp_established_options*()
 	 */

@@ -1336,6 +1325,10 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
 			}
 			ptr += 1;
 		}
+
+		/* We might need to add MP_FAIL options in rare cases */
+		if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions))
+			goto mp_fail;
 	} else if (OPTIONS_MPTCP_MPC & opts->suboptions) {
 		u8 len, flag = MPTCP_CAP_HMAC_SHA256;
 

@@ -1476,6 +1469,21 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
 		put_unaligned_be64(opts->rcvr_key, ptr);
 		ptr += 2;
 
+		if (OPTION_MPTCP_RST & opts->suboptions)
+			goto mp_rst;
+		return;
+	} else if (unlikely(OPTION_MPTCP_FAIL & opts->suboptions)) {
+mp_fail:
+		/* MP_FAIL is mutually exclusive with others except RST */
+		subflow = mptcp_subflow_ctx(ssk);
+		subflow->send_mp_fail = 0;
+
+		*ptr++ = mptcp_option(MPTCPOPT_MP_FAIL,
+				      TCPOLEN_MPTCP_FAIL,
+				      0, 0);
+		put_unaligned_be64(opts->fail_seq, ptr);
+		ptr += 2;
+
 		if (OPTION_MPTCP_RST & opts->suboptions)
 			goto mp_rst;
 		return;

@@ -1267,8 +1267,27 @@ void mptcp_write_options(__be32 *ptr, const struct tcp_sock *tp,
 	const struct sock *ssk = (const struct sock *)tp;
 	struct mptcp_subflow_context *subflow;
 
-	/* DSS, MPC, MPJ, ADD_ADDR, FASTCLOSE and RST are mutually exclusive,
-	 * see mptcp_established_options*()
+	/* Which options can be used together?
+	 *
+	 * X: mutually exclusive
+	 * O: often used together
+	 * C: can be used together in some cases
+	 * P: could be used together but we prefer not to (optimisations)
+	 *
+	 *  Opt: | MPC  | MPJ  | DSS  | ADD  |  RM  | PRIO | FAIL |  FC  |
+	 * ------|------|------|------|------|------|------|------|------|
+	 *  MPC  |------|------|------|------|------|------|------|------|
+	 *  MPJ  |  X   |------|------|------|------|------|------|------|
+	 *  DSS  |  X   |  X   |------|------|------|------|------|------|
+	 *  ADD  |  X   |  X   |  P   |------|------|------|------|------|
+	 *  RM   |  C   |  C   |  C   |  P   |------|------|------|------|
+	 *  PRIO |  X   |  C   |  C   |  C   |  C   |------|------|------|
+	 *  FAIL |  X   |  X   |  C   |  X   |  X   |  X   |------|------|
+	 *  FC   |  X   |  X   |  X   |  X   |  X   |  X   |  X   |------|
+	 *  RST  |  X   |  X   |  X   |  X   |  X   |  X   |  O   |  O   |
+	 * ------|------|------|------|------|------|------|------|------|
+	 *
+	 * The same applies in mptcp_established_options() function.
 	 */
 	if (likely(OPTION_MPTCP_DSS & opts->suboptions)) {
 		struct mptcp_ext *mpext = &opts->ext_copy;

@@ -1728,9 +1728,20 @@ mptcp_nl_cmd_get_limits(struct sk_buff *skb, struct genl_info *info)
 	return -EMSGSIZE;
 }
 
-static int mptcp_nl_addr_backup(struct net *net,
-				struct mptcp_addr_info *addr,
-				u8 bkup)
+static void mptcp_pm_nl_fullmesh(struct mptcp_sock *msk,
+				 struct mptcp_addr_info *addr)
+{
+	struct mptcp_rm_list list = { .nr = 0 };
+
+	list.ids[list.nr++] = addr->id;
+
+	mptcp_pm_nl_rm_subflow_received(msk, &list);
+	mptcp_pm_create_subflow_or_signal_addr(msk);
+}
+
+static int mptcp_nl_set_flags(struct net *net,
+			      struct mptcp_addr_info *addr,
+			      u8 bkup, u8 changed)
 {
 	long s_slot = 0, s_num = 0;
 	struct mptcp_sock *msk;

@@ -1744,7 +1755,10 @@ static int mptcp_nl_addr_backup(struct net *net,
 
 		lock_sock(sk);
 		spin_lock_bh(&msk->pm.lock);
-		ret = mptcp_pm_nl_mp_prio_send_ack(msk, addr, bkup);
+		if (changed & MPTCP_PM_ADDR_FLAG_BACKUP)
+			ret = mptcp_pm_nl_mp_prio_send_ack(msk, addr, bkup);
+		if (changed & MPTCP_PM_ADDR_FLAG_FULLMESH)
+			mptcp_pm_nl_fullmesh(msk, addr);
 		spin_unlock_bh(&msk->pm.lock);
 		release_sock(sk);
 

@@ -1761,6 +1775,8 @@ static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info)
 	struct mptcp_pm_addr_entry addr = { .addr = { .family = AF_UNSPEC }, }, *entry;
 	struct nlattr *attr = info->attrs[MPTCP_PM_ATTR_ADDR];
 	struct pm_nl_pernet *pernet = genl_info_pm_nl(info);
+	u8 changed, mask = MPTCP_PM_ADDR_FLAG_BACKUP |
+			   MPTCP_PM_ADDR_FLAG_FULLMESH;
 	struct net *net = sock_net(skb->sk);
 	u8 bkup = 0, lookup_by_id = 0;
 	int ret;

@@ -1783,15 +1799,18 @@ static int mptcp_nl_cmd_set_flags(struct sk_buff *skb, struct genl_info *info)
 		spin_unlock_bh(&pernet->lock);
 		return -EINVAL;
 	}
+	if ((addr.flags & MPTCP_PM_ADDR_FLAG_FULLMESH) &&
+	    (entry->flags & MPTCP_PM_ADDR_FLAG_SIGNAL)) {
+		spin_unlock_bh(&pernet->lock);
+		return -EINVAL;
+	}
 
-	if (bkup)
-		entry->flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
-	else
-		entry->flags &= ~MPTCP_PM_ADDR_FLAG_BACKUP;
+	changed = (addr.flags ^ entry->flags) & mask;
+	entry->flags = (entry->flags & ~mask) | (addr.flags & mask);
 	addr = *entry;
 	spin_unlock_bh(&pernet->lock);
 
-	mptcp_nl_addr_backup(net, &addr.addr, bkup);
+	mptcp_nl_set_flags(net, &addr.addr, bkup, changed);
 	return 0;
 }
 

@@ -28,7 +28,7 @@ static void syntax(char *argv[])
 	fprintf(stderr, "\tadd [flags signal|subflow|backup|fullmesh] [id <nr>] [dev <name>] <ip>\n");
 	fprintf(stderr, "\tdel <id> [<ip>]\n");
 	fprintf(stderr, "\tget <id>\n");
-	fprintf(stderr, "\tset <ip> [flags backup|nobackup]\n");
+	fprintf(stderr, "\tset <ip> [flags backup|nobackup|fullmesh|nofullmesh]\n");
 	fprintf(stderr, "\tflush\n");
 	fprintf(stderr, "\tdump\n");
 	fprintf(stderr, "\tlimits [<rcv addr max> <subflow max>]\n");

@@ -704,12 +704,14 @@ int set_flags(int fd, int pm_family, int argc, char *argv[])
 			if (++arg >= argc)
 				error(1, 0, " missing flags value");
 
-			/* do not support flag list yet */
 			for (str = argv[arg]; (tok = strtok(str, ","));
 			     str = NULL) {
 				if (!strcmp(tok, "backup"))
 					flags |= MPTCP_PM_ADDR_FLAG_BACKUP;
-				else if (strcmp(tok, "nobackup"))
+				else if (!strcmp(tok, "fullmesh"))
+					flags |= MPTCP_PM_ADDR_FLAG_FULLMESH;
+				else if (strcmp(tok, "nobackup") &&
+					 strcmp(tok, "nofullmesh"))
 					error(1, errno,
 					      "unknown flag %s", argv[arg]);
 			}

@@ -289,7 +289,7 @@ do_transfer()
 	addr_nr_ns1="$7"
 	addr_nr_ns2="$8"
 	speed="$9"
-	bkup="${10}"
+	sflags="${10}"
 
 	port=$((10000+$TEST_COUNT))
 	TEST_COUNT=$((TEST_COUNT+1))

@@ -461,14 +461,13 @@ do_transfer()
 		fi
 	fi
 
-	if [ ! -z $bkup ]; then
+	if [ ! -z $sflags ]; then
 		sleep 1
 		for netns in "$ns1" "$ns2"; do
 			dump=(`ip netns exec $netns ./pm_nl_ctl dump`)
 			if [ ${#dump[@]} -gt 0 ]; then
 				addr=${dump[${#dump[@]} - 1]}
-				backup="ip netns exec $netns ./pm_nl_ctl set $addr flags $bkup"
-				$backup
+				ip netns exec $netns ./pm_nl_ctl set $addr flags $sflags
 			fi
 		done
 	fi

@@ -545,7 +544,7 @@ run_tests()
 	addr_nr_ns1="${5:-0}"
 	addr_nr_ns2="${6:-0}"
 	speed="${7:-fast}"
-	bkup="${8:-""}"
+	sflags="${8:-""}"
 	lret=0
 	oldin=""
 

@@ -574,7 +573,7 @@ run_tests()
 	fi
 
 	do_transfer ${listener_ns} ${connector_ns} MPTCP MPTCP ${connect_addr} \
-		${test_linkfail} ${addr_nr_ns1} ${addr_nr_ns2} ${speed} ${bkup}
+		${test_linkfail} ${addr_nr_ns1} ${addr_nr_ns2} ${speed} ${sflags}
 	lret=$?
 }
 

@@ -1888,6 +1887,44 @@ fullmesh_tests()
 	run_tests $ns1 $ns2 10.0.1.1 0 0 fullmesh_2 slow
 	chk_join_nr "fullmesh test 1x2, limited" 4 4 4
 	chk_add_nr 1 1
+
+	# set fullmesh flag
+	reset
+	ip netns exec $ns1 ./pm_nl_ctl limits 4 4
+	ip netns exec $ns1 ./pm_nl_ctl add 10.0.2.1 flags subflow
+	ip netns exec $ns2 ./pm_nl_ctl limits 4 4
+	run_tests $ns1 $ns2 10.0.1.1 0 0 1 slow fullmesh
+	chk_join_nr "set fullmesh flag test" 2 2 2
+	chk_rm_nr 0 1
+
+	# set nofullmesh flag
+	reset
+	ip netns exec $ns1 ./pm_nl_ctl limits 4 4
+	ip netns exec $ns1 ./pm_nl_ctl add 10.0.2.1 flags subflow,fullmesh
+	ip netns exec $ns2 ./pm_nl_ctl limits 4 4
+	run_tests $ns1 $ns2 10.0.1.1 0 0 fullmesh_1 slow nofullmesh
+	chk_join_nr "set nofullmesh flag test" 2 2 2
+	chk_rm_nr 0 1
+
+	# set backup,fullmesh flags
+	reset
+	ip netns exec $ns1 ./pm_nl_ctl limits 4 4
+	ip netns exec $ns1 ./pm_nl_ctl add 10.0.2.1 flags subflow
+	ip netns exec $ns2 ./pm_nl_ctl limits 4 4
+	run_tests $ns1 $ns2 10.0.1.1 0 0 1 slow backup,fullmesh
+	chk_join_nr "set backup,fullmesh flags test" 2 2 2
+	chk_prio_nr 0 1
+	chk_rm_nr 0 1
+
+	# set nobackup,nofullmesh flags
+	reset
+	ip netns exec $ns1 ./pm_nl_ctl limits 4 4
+	ip netns exec $ns2 ./pm_nl_ctl limits 4 4
+	ip netns exec $ns2 ./pm_nl_ctl add 10.0.2.2 flags subflow,backup,fullmesh
+	run_tests $ns1 $ns2 10.0.1.1 0 0 0 slow nobackup,nofullmesh
+	chk_join_nr "set nobackup,nofullmesh flags test" 2 2 2
+	chk_prio_nr 0 1
+	chk_rm_nr 0 1
 }
 
 all_tests()