Commit 1c1f14f9 authored by Jakub Kicinski's avatar Jakub Kicinski
Browse files

Merge branch 'mptcp-fixes-for-v6-6' 

Mat Martineau says:

====================
mptcp: Fixes for v6.6

Patch 1 corrects the logic for MP_JOIN tests where 0 RSTs are expected.

Patch 2 ensures MPTCP packets are not incorrectly coalesced in the TCP
backlog queue.

Patch 3 avoids a zero-window probe and associated WARN_ON_ONCE() in an
expected MPTCP reinjection scenario.

Patches 4 & 5 allow an initial MPTCP subflow to be closed cleanly
instead of always sending RST. Associated selftest is updated.
====================

Link: https://lore.kernel.org/r/20231018-send-net-20231018-v1-0-17ecb002e41d@kernel.org


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parents 389db4fd 2cfaa8b3

net/ipv4/tcp_ipv4.c

+1 −0
Original line number Diff line number Diff line
@@ -1869,6 +1869,7 @@ bool tcp_add_backlog(struct sock *sk, struct sk_buff *skb, 
#ifdef CONFIG_TLS_DEVICE

	    tail->decrypted != skb->decrypted ||

#endif

	    !mptcp_skb_can_collapse(tail, skb) ||

	    thtail->doff != th->doff ||

	    memcmp(thtail + 1, th + 1, hdrlen - sizeof(*th)))

		goto no_coalesce;

net/mptcp/protocol.c

+23 −13
Original line number Diff line number Diff line
@@ -1298,7 +1298,7 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, 
	if (copy == 0) {

		u64 snd_una = READ_ONCE(msk->snd_una);



		if (snd_una != msk->snd_nxt) {

		if (snd_una != msk->snd_nxt || tcp_write_queue_tail(ssk)) {

			tcp_remove_empty_skb(ssk);

			return 0;

		}
@@ -1306,11 +1306,6 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, 
		zero_window_probe = true;

		data_seq = snd_una - 1;

		copy = 1;



		/* all mptcp-level data is acked, no skbs should be present into the

		 * ssk write queue

		 */

		WARN_ON_ONCE(reuse_skb);

	}



	copy = min_t(size_t, copy, info->limit - info->sent);
@@ -1339,7 +1334,6 @@ static int mptcp_sendmsg_frag(struct sock *sk, struct sock *ssk, 
	if (reuse_skb) {

		TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_PSH;

		mpext->data_len += copy;

		WARN_ON_ONCE(zero_window_probe);

		goto out;

	}
@@ -2354,6 +2348,26 @@ bool __mptcp_retransmit_pending_data(struct sock *sk) 
#define MPTCP_CF_PUSH		BIT(1)

#define MPTCP_CF_FASTCLOSE	BIT(2)



/* be sure to send a reset only if the caller asked for it, also

 * clean completely the subflow status when the subflow reaches

 * TCP_CLOSE state

 */

static void __mptcp_subflow_disconnect(struct sock *ssk,

				       struct mptcp_subflow_context *subflow,

				       unsigned int flags)

{

	if (((1 << ssk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) ||

	    (flags & MPTCP_CF_FASTCLOSE)) {

		/* The MPTCP code never wait on the subflow sockets, TCP-level

		 * disconnect should never fail

		 */

		WARN_ON_ONCE(tcp_disconnect(ssk, 0));

		mptcp_subflow_ctx_reset(subflow);

	} else {

		tcp_shutdown(ssk, SEND_SHUTDOWN);

	}

}



/* subflow sockets can be either outgoing (connect) or incoming

 * (accept).

 *
@@ -2391,7 +2405,7 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, 
	lock_sock_nested(ssk, SINGLE_DEPTH_NESTING);



	if ((flags & MPTCP_CF_FASTCLOSE) && !__mptcp_check_fallback(msk)) {

		/* be sure to force the tcp_disconnect() path,

		/* be sure to force the tcp_close path

		 * to generate the egress reset

		 */

		ssk->sk_lingertime = 0;
@@ -2401,11 +2415,7 @@ static void __mptcp_close_ssk(struct sock *sk, struct sock *ssk, 


	need_push = (flags & MPTCP_CF_PUSH) && __mptcp_retransmit_pending_data(sk);

	if (!dispose_it) {

		/* The MPTCP code never wait on the subflow sockets, TCP-level

		 * disconnect should never fail

		 */

		WARN_ON_ONCE(tcp_disconnect(ssk, 0));

		mptcp_subflow_ctx_reset(subflow);

		__mptcp_subflow_disconnect(ssk, subflow, flags);

		release_sock(ssk);



		goto out;

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

+19 −2
Original line number Diff line number Diff line
@@ -1432,7 +1432,9 @@ chk_rst_nr() 
	count=$(get_counter ${ns_tx} "MPTcpExtMPRstTx")

	if [ -z "$count" ]; then

		print_skip

	elif [ $count -lt $rst_tx ]; then

	# accept more rst than expected except if we don't expect any

	elif { [ $rst_tx -ne 0 ] && [ $count -lt $rst_tx ]; } ||

	     { [ $rst_tx -eq 0 ] && [ $count -ne 0 ]; }; then

		fail_test "got $count MP_RST[s] TX expected $rst_tx"

	else

		print_ok
@@ -1442,7 +1444,9 @@ chk_rst_nr() 
	count=$(get_counter ${ns_rx} "MPTcpExtMPRstRx")

	if [ -z "$count" ]; then

		print_skip

	elif [ "$count" -lt "$rst_rx" ]; then

	# accept more rst than expected except if we don't expect any

	elif { [ $rst_rx -ne 0 ] && [ $count -lt $rst_rx ]; } ||

	     { [ $rst_rx -eq 0 ] && [ $count -ne 0 ]; }; then

		fail_test "got $count MP_RST[s] RX expected $rst_rx"

	else

		print_ok
@@ -2305,6 +2309,7 @@ remove_tests() 
		chk_join_nr 1 1 1

		chk_rm_tx_nr 1

		chk_rm_nr 1 1

		chk_rst_nr 0 0

	fi



	# multiple subflows, remove
@@ -2317,6 +2322,7 @@ remove_tests() 
			run_tests $ns1 $ns2 10.0.1.1

		chk_join_nr 2 2 2

		chk_rm_nr 2 2

		chk_rst_nr 0 0

	fi



	# single address, remove
@@ -2329,6 +2335,7 @@ remove_tests() 
		chk_join_nr 1 1 1

		chk_add_nr 1 1

		chk_rm_nr 1 1 invert

		chk_rst_nr 0 0

	fi



	# subflow and signal, remove
@@ -2342,6 +2349,7 @@ remove_tests() 
		chk_join_nr 2 2 2

		chk_add_nr 1 1

		chk_rm_nr 1 1

		chk_rst_nr 0 0

	fi



	# subflows and signal, remove
@@ -2356,6 +2364,7 @@ remove_tests() 
		chk_join_nr 3 3 3

		chk_add_nr 1 1

		chk_rm_nr 2 2

		chk_rst_nr 0 0

	fi



	# addresses remove
@@ -2370,6 +2379,7 @@ remove_tests() 
		chk_join_nr 3 3 3

		chk_add_nr 3 3

		chk_rm_nr 3 3 invert

		chk_rst_nr 0 0

	fi



	# invalid addresses remove
@@ -2384,6 +2394,7 @@ remove_tests() 
		chk_join_nr 1 1 1

		chk_add_nr 3 3

		chk_rm_nr 3 1 invert

		chk_rst_nr 0 0

	fi



	# subflows and signal, flush
@@ -2398,6 +2409,7 @@ remove_tests() 
		chk_join_nr 3 3 3

		chk_add_nr 1 1

		chk_rm_nr 1 3 invert simult

		chk_rst_nr 0 0

	fi



	# subflows flush
@@ -2417,6 +2429,7 @@ remove_tests() 
		else

			chk_rm_nr 3 3

		fi

		chk_rst_nr 0 0

	fi



	# addresses flush
@@ -2431,6 +2444,7 @@ remove_tests() 
		chk_join_nr 3 3 3

		chk_add_nr 3 3

		chk_rm_nr 3 3 invert simult

		chk_rst_nr 0 0

	fi



	# invalid addresses flush
@@ -2445,6 +2459,7 @@ remove_tests() 
		chk_join_nr 1 1 1

		chk_add_nr 3 3

		chk_rm_nr 3 1 invert

		chk_rst_nr 0 0

	fi



	# remove id 0 subflow
@@ -2456,6 +2471,7 @@ remove_tests() 
			run_tests $ns1 $ns2 10.0.1.1

		chk_join_nr 1 1 1

		chk_rm_nr 1 1

		chk_rst_nr 0 0

	fi



	# remove id 0 address
@@ -2468,6 +2484,7 @@ remove_tests() 
		chk_join_nr 1 1 1

		chk_add_nr 1 1

		chk_rm_nr 1 1 invert

		chk_rst_nr 0 0 invert

	fi

}