rxrpc: Fix call timeouts

Fix the rxrpc call expiration timeouts and make them settable from
userspace.  By analogy with other rx implementations, there should be three
timeouts:

 (1) "Normal timeout"

     This is set for all calls and is triggered if we haven't received any
     packets from the peer in a while.  It is measured from the last time
     we received any packet on that call.  This is not reset by any
     connection packets (such as CHALLENGE/RESPONSE packets).

     If a service operation takes a long time, the server should generate
     PING ACKs at a duration that's substantially less than the normal
     timeout so is to keep both sides alive.  This is set at 1/6 of normal
     timeout.

 (2) "Idle timeout"

     This is set only for a service call and is triggered if we stop
     receiving the DATA packets that comprise the request data.  It is
     measured from the last time we received a DATA packet.

 (3) "Hard timeout"

     This can be set for a call and specified the maximum lifetime of that
     call.  It should not be specified by default.  Some operations (such
     as volume transfer) take a long time.

Allow userspace to set/change the timeouts on a call with sendmsg, using a
control message:

	RXRPC_SET_CALL_TIMEOUTS

The data to the message is a number of 32-bit words, not all of which need
be given:

	u32 hard_timeout;	/* sec from first packet */
	u32 idle_timeout;	/* msec from packet Rx */
	u32 normal_timeout;	/* msec from data Rx */

This can be set in combination with any other sendmsg() that affects a
call.

Signed-off-by: David Howells <dhowells@redhat.com>

1 files changed, 49 insertions, 10 deletions

diff --git a/net/rxrpc/sendmsg.c b/net/rxrpc/sendmsg.c
index de5ab327c18a..03e0676db28c 100644
--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -158,6 +158,7 @@ static void rxrpc_queue_packet(struct rxrpc_sock *rx, struct rxrpc_call *call,
 			       rxrpc_notify_end_tx_t notify_end_tx)
 {
 	struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
+	unsigned long now;
 	rxrpc_seq_t seq = sp->hdr.seq;
 	int ret, ix;
 	u8 annotation = RXRPC_TX_ANNO_UNACK;
@@ -197,11 +198,11 @@ static void rxrpc_queue_packet(struct rxrpc_sock *rx, struct rxrpc_call *call,
 			break;
 		case RXRPC_CALL_SERVER_ACK_REQUEST:
 			call->state = RXRPC_CALL_SERVER_SEND_REPLY;
-			call->ack_at = call->expire_at;
+			now = jiffies;
+			WRITE_ONCE(call->ack_at, now + MAX_JIFFY_OFFSET);
 			if (call->ackr_reason == RXRPC_ACK_DELAY)
 				call->ackr_reason = 0;
-			__rxrpc_set_timer(call, rxrpc_timer_init_for_send_reply,
-					  ktime_get_real());
+			trace_rxrpc_timer(call, rxrpc_timer_init_for_send_reply, now);
 			if (!last)
 				break;
 			/* Fall through */
@@ -223,14 +224,12 @@ static void rxrpc_queue_packet(struct rxrpc_sock *rx, struct rxrpc_call *call,
 		_debug("need instant resend %d", ret);
 		rxrpc_instant_resend(call, ix);
 	} else {
-		ktime_t now = ktime_get_real(), resend_at;
+		unsigned long now = jiffies, resend_at;
 
-		resend_at = ktime_add_ms(now, rxrpc_resend_timeout);
-
-		if (ktime_before(resend_at, call->resend_at)) {
-			call->resend_at = resend_at;
-			rxrpc_set_timer(call, rxrpc_timer_set_for_send, now);
-		}
+		resend_at = now + rxrpc_resend_timeout;
+		WRITE_ONCE(call->resend_at, resend_at);
+		rxrpc_reduce_call_timer(call, resend_at, now,
+					rxrpc_timer_set_for_send);
 	}
 
 	rxrpc_free_skb(skb, rxrpc_skb_tx_freed);
@@ -513,6 +512,19 @@ static int rxrpc_sendmsg_cmsg(struct msghdr *msg, struct rxrpc_send_params *p)
 				return -EINVAL;
 			break;
 
+		case RXRPC_SET_CALL_TIMEOUT:
+			if (len & 3 || len < 4 || len > 12)
+				return -EINVAL;
+			memcpy(&p->call.timeouts, CMSG_DATA(cmsg), len);
+			p->call.nr_timeouts = len / 4;
+			if (p->call.timeouts.hard > INT_MAX / HZ)
+				return -ERANGE;
+			if (p->call.nr_timeouts >= 2 && p->call.timeouts.idle > 60 * 60 * 1000)
+				return -ERANGE;
+			if (p->call.nr_timeouts >= 3 && p->call.timeouts.normal > 60 * 60 * 1000)
+				return -ERANGE;
+			break;
+
 		default:
 			return -EINVAL;
 		}
@@ -577,11 +589,13 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
 {
 	enum rxrpc_call_state state;
 	struct rxrpc_call *call;
+	unsigned long now, j;
 	int ret;
 
 	struct rxrpc_send_params p = {
 		.call.tx_total_len	= -1,
 		.call.user_call_ID	= 0,
+		.call.nr_timeouts	= 0,
 		.abort_code		= 0,
 		.command		= RXRPC_CMD_SEND_DATA,
 		.exclusive		= false,
@@ -646,6 +660,31 @@ int rxrpc_do_sendmsg(struct rxrpc_sock *rx, struct msghdr *msg, size_t len)
 		}
 	}
 
+	switch (p.call.nr_timeouts) {
+	case 3:
+		j = msecs_to_jiffies(p.call.timeouts.normal);
+		if (p.call.timeouts.normal > 0 && j == 0)
+			j = 1;
+		WRITE_ONCE(call->next_rx_timo, j);
+		/* Fall through */
+	case 2:
+		j = msecs_to_jiffies(p.call.timeouts.idle);
+		if (p.call.timeouts.idle > 0 && j == 0)
+			j = 1;
+		WRITE_ONCE(call->next_req_timo, j);
+		/* Fall through */
+	case 1:
+		if (p.call.timeouts.hard > 0) {
+			j = msecs_to_jiffies(p.call.timeouts.hard);
+			now = jiffies;
+			j += now;
+			WRITE_ONCE(call->expect_term_by, j);
+			rxrpc_reduce_call_timer(call, j, now,
+						rxrpc_timer_set_for_hard);
+		}
+		break;
+	}
+
 	state = READ_ONCE(call->state);
 	_debug("CALL %d USR %lx ST %d on CONN %p",
 	       call->debug_id, call->user_call_ID, state, call->conn);