Merge branch 'mptcp-more-misc-fixes-for-v6-8'

Matthieu Baerts says:

====================
mptcp: more misc. fixes for v6.8

This series includes 6 types of fixes:

- Patch 1 fixes v4 mapped in v6 addresses support for the userspace PM,
  when asking to delete a subflow. It was done everywhere else, but not
  there. Patch 2 validates the modification, thanks to a subtest in
  mptcp_join.sh. These patches can be backported up to v5.19.

- Patch 3 is a small fix for a recent bug-fix patch, just to avoid
  printing an irrelevant warning (pr_warn()) once. It can be backported
  up to v5.6, alongside the bug-fix that has been introduced in the
  v6.8-rc5.

- Patches 4 to 6 are fixes for bugs found by Paolo while working on
  TCP_NOTSENT_LOWAT support for MPTCP. These fixes can improve the
  performances in some cases. Patches can be backported up to v5.6,
  v5.11 and v6.7 respectively.

- Patch 7 makes sure 'ss -M' is available when starting MPTCP Join
  selftest as it is required for some subtests since v5.18.

- Patch 8 fixes a possible double-free on socket dismantle. The issue
  always existed, but was unnoticed because it was not causing any
  problem so far. This fix can be backported up to v5.6.

- Patch 9 is a fix for a very recent patch causing lockdep warnings in
  subflow diag. The patch causing the regression -- which fixes another
  issue present since v5.7 -- should be part of the future v6.8-rc6.
  Patch 10 validates the modification, thanks to a new subtest in
  diag.sh.
====================

Link: https://lore.kernel.org/r/20240223-upstream-net-20240223-misc-fixes-v1-0-162e87e48497@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net/mptcp/diag.c

@@ -21,6 +21,9 @@ static int subflow_get_info(struct sock *sk, struct sk_buff *skb)
 	bool slow;
 	int err;
 
+	if (inet_sk_state_load(sk) == TCP_LISTEN)
+		return 0;
+
 	start = nla_nest_start_noflag(skb, INET_ULP_INFO_MPTCP);
 	if (!start)
 		return -EMSGSIZE;

net/mptcp/options.c

@@ -981,10 +981,10 @@ static bool check_fully_established(struct mptcp_sock *msk, struct sock *ssk,
 	if (mp_opt->deny_join_id0)
 		WRITE_ONCE(msk->pm.remote_deny_join_id0, true);
 
-set_fully_established:
 	if (unlikely(!READ_ONCE(msk->pm.server_side)))
 		pr_warn_once("bogus mpc option on established client sk");
 
+set_fully_established:
 	mptcp_data_lock((struct sock *)msk);
 	__mptcp_subflow_fully_established(msk, subflow, mp_opt);
 	mptcp_data_unlock((struct sock *)msk);

net/mptcp/pm_userspace.c

@@ -495,6 +495,16 @@ int mptcp_pm_nl_subflow_destroy_doit(struct sk_buff *skb, struct genl_info *info
 		goto destroy_err;
 	}
 
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	if (addr_l.family == AF_INET && ipv6_addr_v4mapped(&addr_r.addr6)) {
+		ipv6_addr_set_v4mapped(addr_l.addr.s_addr, &addr_l.addr6);
+		addr_l.family = AF_INET6;
+	}
+	if (addr_r.family == AF_INET && ipv6_addr_v4mapped(&addr_l.addr6)) {
+		ipv6_addr_set_v4mapped(addr_r.addr.s_addr, &addr_r.addr6);
+		addr_r.family = AF_INET6;
+	}
+#endif
 	if (addr_l.family != addr_r.family) {
 		GENL_SET_ERR_MSG(info, "address families do not match");
 		err = -EINVAL;

net/mptcp/protocol.c

@@ -1260,6 +1260,7 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk,
 		mpext = mptcp_get_ext(skb);
 		if (!mptcp_skb_can_collapse_to(data_seq, skb, mpext)) {
 			TCP_SKB_CB(skb)->eor = 1;
+			tcp_mark_push(tcp_sk(ssk), skb);
 			goto alloc_skb;
 		}
 
@@ -3177,8 +3178,50 @@ static struct ipv6_pinfo *mptcp_inet6_sk(const struct sock *sk)
 
 	return (struct ipv6_pinfo *)(((u8 *)sk) + offset);
 }
+
+static void mptcp_copy_ip6_options(struct sock *newsk, const struct sock *sk)
+{
+	const struct ipv6_pinfo *np = inet6_sk(sk);
+	struct ipv6_txoptions *opt;
+	struct ipv6_pinfo *newnp;
+
+	newnp = inet6_sk(newsk);
+
+	rcu_read_lock();
+	opt = rcu_dereference(np->opt);
+	if (opt) {
+		opt = ipv6_dup_options(newsk, opt);
+		if (!opt)
+			net_warn_ratelimited("%s: Failed to copy ip6 options\n", __func__);
+	}
+	RCU_INIT_POINTER(newnp->opt, opt);
+	rcu_read_unlock();
+}
 #endif
 
+static void mptcp_copy_ip_options(struct sock *newsk, const struct sock *sk)
+{
+	struct ip_options_rcu *inet_opt, *newopt = NULL;
+	const struct inet_sock *inet = inet_sk(sk);
+	struct inet_sock *newinet;
+
+	newinet = inet_sk(newsk);
+
+	rcu_read_lock();
+	inet_opt = rcu_dereference(inet->inet_opt);
+	if (inet_opt) {
+		newopt = sock_kmalloc(newsk, sizeof(*inet_opt) +
+				      inet_opt->opt.optlen, GFP_ATOMIC);
+		if (newopt)
+			memcpy(newopt, inet_opt, sizeof(*inet_opt) +
+			       inet_opt->opt.optlen);
+		else
+			net_warn_ratelimited("%s: Failed to copy ip options\n", __func__);
+	}
+	RCU_INIT_POINTER(newinet->inet_opt, newopt);
+	rcu_read_unlock();
+}
+
 struct sock *mptcp_sk_clone_init(const struct sock *sk,
 				 const struct mptcp_options_received *mp_opt,
 				 struct sock *ssk,
@@ -3199,6 +3242,13 @@ struct sock *mptcp_sk_clone_init(const struct sock *sk,
 
 	__mptcp_init_sock(nsk);
 
+#if IS_ENABLED(CONFIG_MPTCP_IPV6)
+	if (nsk->sk_family == AF_INET6)
+		mptcp_copy_ip6_options(nsk, sk);
+	else
+#endif
+		mptcp_copy_ip_options(nsk, sk);
+
 	msk = mptcp_sk(nsk);
 	msk->local_key = subflow_req->local_key;
 	msk->token = subflow_req->token;
@@ -3210,7 +3260,7 @@ struct sock *mptcp_sk_clone_init(const struct sock *sk,
 	msk->write_seq = subflow_req->idsn + 1;
 	msk->snd_nxt = msk->write_seq;
 	msk->snd_una = msk->write_seq;
-	msk->wnd_end = msk->snd_nxt + req->rsk_rcv_wnd;
+	msk->wnd_end = msk->snd_nxt + tcp_sk(ssk)->snd_wnd;
 	msk->setsockopt_seq = mptcp_sk(sk)->setsockopt_seq;
 	mptcp_init_sched(msk, mptcp_sk(sk)->sched);
 

net/mptcp/protocol.h

@@ -790,6 +790,16 @@ static inline bool mptcp_data_fin_enabled(const struct mptcp_sock *msk)
 	       READ_ONCE(msk->write_seq) == READ_ONCE(msk->snd_nxt);
 }
 
+static inline void mptcp_write_space(struct sock *sk)
+{
+	if (sk_stream_is_writeable(sk)) {
+		/* pairs with memory barrier in mptcp_poll */
+		smp_mb();
+		if (test_and_clear_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags))
+			sk_stream_write_space(sk);
+	}
+}
+
 static inline void __mptcp_sync_sndbuf(struct sock *sk)
 {
 	struct mptcp_subflow_context *subflow;
@@ -808,6 +818,7 @@ static inline void __mptcp_sync_sndbuf(struct sock *sk)
 
 	/* the msk max wmem limit is <nr_subflows> * tcp wmem[2] */
 	WRITE_ONCE(sk->sk_sndbuf, new_sndbuf);
+	mptcp_write_space(sk);
 }
 
 /* The called held both the msk socket and the subflow socket locks,
@@ -838,16 +849,6 @@ static inline void mptcp_propagate_sndbuf(struct sock *sk, struct sock *ssk)
 	local_bh_enable();
 }
 
-static inline void mptcp_write_space(struct sock *sk)
-{
-	if (sk_stream_is_writeable(sk)) {
-		/* pairs with memory barrier in mptcp_poll */
-		smp_mb();
-		if (test_and_clear_bit(MPTCP_NOSPACE, &mptcp_sk(sk)->flags))
-			sk_stream_write_space(sk);
-	}
-}
-
 void mptcp_destroy_common(struct mptcp_sock *msk, unsigned int flags);
 
 #define MPTCP_TOKEN_MAX_RETRIES	4

tools/testing/selftests/net/mptcp/diag.sh

@@ -20,7 +20,7 @@ flush_pids()
 
 	ip netns pids "${ns}" | xargs --no-run-if-empty kill -SIGUSR1 &>/dev/null
 
-	for _ in $(seq 10); do
+	for _ in $(seq $((timeout_poll * 10))); do
 		[ -z "$(ip netns pids "${ns}")" ] && break
 		sleep 0.1
 	done
@@ -91,6 +91,15 @@ chk_msk_nr()
 	__chk_msk_nr "grep -c token:" "$@"
 }
 
+chk_listener_nr()
+{
+	local expected=$1
+	local msg="$2"
+
+	__chk_nr "ss -inmlHMON $ns | wc -l" "$expected" "$msg - mptcp" 0
+	__chk_nr "ss -inmlHtON $ns | wc -l" "$expected" "$msg - subflows"
+}
+
 wait_msk_nr()
 {
 	local condition="grep -c token:"
@@ -289,5 +298,24 @@ flush_pids
 chk_msk_inuse 0 "many->0"
 chk_msk_cestab 0 "many->0"
 
+chk_listener_nr 0 "no listener sockets"
+NR_SERVERS=100
+for I in $(seq 1 $NR_SERVERS); do
+	ip netns exec $ns ./mptcp_connect -p $((I + 20001)) \
+		-t ${timeout_poll} -l 0.0.0.0 >/dev/null 2>&1 &
+done
+
+for I in $(seq 1 $NR_SERVERS); do
+	mptcp_lib_wait_local_port_listen $ns $((I + 20001))
+done
+
+chk_listener_nr $NR_SERVERS "many listener sockets"
+
+# graceful termination
+for I in $(seq 1 $NR_SERVERS); do
+	echo a | ip netns exec $ns ./mptcp_connect -p $((I + 20001)) 127.0.0.1 >/dev/null 2>&1 &
+done
+flush_pids
+
 mptcp_lib_result_print_all_tap
 exit $ret

tools/testing/selftests/net/mptcp/mptcp_join.sh

@@ -161,6 +161,11 @@ check_tools()
 		exit $ksft_skip
 	fi
 
+	if ! ss -h | grep -q MPTCP; then
+		echo "SKIP: ss tool does not support MPTCP"
+		exit $ksft_skip
+	fi
+
 	# Use the legacy version if available to support old kernel versions
 	if iptables-legacy -V &> /dev/null; then
 		iptables="iptables-legacy"
@@ -3333,16 +3338,17 @@ userspace_pm_rm_sf()
 {
 	local evts=$evts_ns1
 	local t=${3:-1}
-	local ip=4
+	local ip
 	local tk da dp sp
 	local cnt
 
 	[ "$1" == "$ns2" ] && evts=$evts_ns2
-	if mptcp_lib_is_v6 $2; then ip=6; fi
+	[ -n "$(mptcp_lib_evts_get_info "saddr4" "$evts" $t)" ] && ip=4
+	[ -n "$(mptcp_lib_evts_get_info "saddr6" "$evts" $t)" ] && ip=6
 	tk=$(mptcp_lib_evts_get_info token "$evts")
-	da=$(mptcp_lib_evts_get_info "daddr$ip" "$evts" $t)
-	dp=$(mptcp_lib_evts_get_info dport "$evts" $t)
-	sp=$(mptcp_lib_evts_get_info sport "$evts" $t)
+	da=$(mptcp_lib_evts_get_info "daddr$ip" "$evts" $t $2)
+	dp=$(mptcp_lib_evts_get_info dport "$evts" $t $2)
+	sp=$(mptcp_lib_evts_get_info sport "$evts" $t $2)
 
 	cnt=$(rm_sf_count ${1})
 	ip netns exec $1 ./pm_nl_ctl dsf lip $2 lport $sp \
@@ -3429,20 +3435,23 @@ userspace_tests()
 	if reset_with_events "userspace pm add & remove address" &&
 	   continue_if mptcp_lib_has_file '/proc/sys/net/mptcp/pm_type'; then
 		set_userspace_pm $ns1
-		pm_nl_set_limits $ns2 1 1
+		pm_nl_set_limits $ns2 2 2
 		speed=5 \
 			run_tests $ns1 $ns2 10.0.1.1 &
 		local tests_pid=$!
 		wait_mpj $ns1
 		userspace_pm_add_addr $ns1 10.0.2.1 10
-		chk_join_nr 1 1 1
-		chk_add_nr 1 1
-		chk_mptcp_info subflows 1 subflows 1
-		chk_subflows_total 2 2
-		chk_mptcp_info add_addr_signal 1 add_addr_accepted 1
+		userspace_pm_add_addr $ns1 10.0.3.1 20
+		chk_join_nr 2 2 2
+		chk_add_nr 2 2
+		chk_mptcp_info subflows 2 subflows 2
+		chk_subflows_total 3 3
+		chk_mptcp_info add_addr_signal 2 add_addr_accepted 2
 		userspace_pm_rm_addr $ns1 10
 		userspace_pm_rm_sf $ns1 "::ffff:10.0.2.1" $SUB_ESTABLISHED
-		chk_rm_nr 1 1 invert
+		userspace_pm_rm_addr $ns1 20
+		userspace_pm_rm_sf $ns1 10.0.3.1 $SUB_ESTABLISHED
+		chk_rm_nr 2 2 invert
 		chk_mptcp_info subflows 0 subflows 0
 		chk_subflows_total 1 1
 		kill_events_pids

tools/testing/selftests/net/mptcp/mptcp_lib.sh

@@ -213,9 +213,9 @@ mptcp_lib_get_info_value() {
 	grep "${2}" | sed -n 's/.*\('"${1}"':\)\([0-9a-f:.]*\).*$/\2/p;q'
 }
 
-# $1: info name ; $2: evts_ns ; $3: event type
+# $1: info name ; $2: evts_ns ; [$3: event type; [$4: addr]]
 mptcp_lib_evts_get_info() {
-	mptcp_lib_get_info_value "${1}" "^type:${3:-1}," < "${2}"
+	grep "${4:-}" "${2}" | mptcp_lib_get_info_value "${1}" "^type:${3:-1},"
 }
 
 # $1: PID