From 52229de8462dc1414acab832e9c955e7e2e4e55f Mon Sep 17 00:00:00 2001
From: Nico Vergauwen <vergauwennico@gmail.com>
Date: Thu, 6 May 2021 21:01:49 +0200
Subject: [PATCH] pm: refresh ticket params before expiry from sender side

---
 CHANGELOG_PENDING.md |  1 +
 pm/recipient.go      |  1 +
 pm/sender.go         |  4 +++-
 pm/sender_test.go    | 13 ++++++++++++-
 4 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG_PENDING.md b/CHANGELOG_PENDING.md
index 0ed519ee6e..d2622590a0 100644
--- a/CHANGELOG_PENDING.md
+++ b/CHANGELOG_PENDING.md
@@ -13,6 +13,7 @@
 
 - \#1875 Update 'trying to transcode' log statement with manifestID (@kyriediculous)
 - \#1837 Only log discovery errors when request is not cancelled (@yondonfu)
+- \#1877 Refresh TicketParams for the active session before expiry (@kyriediculous)
 
 #### Orchestrator
 
diff --git a/pm/recipient.go b/pm/recipient.go
index 894b2b0b75..6823d0f39f 100644
--- a/pm/recipient.go
+++ b/pm/recipient.go
@@ -22,6 +22,7 @@ var errInsufficientSenderReserve = errors.New("insufficient sender reserve")
 var maxWinProb = new(big.Int).Sub(new(big.Int).Lsh(big.NewInt(1), 256), big.NewInt(1))
 
 var paramsExpirationBlock = big.NewInt(10)
+var paramsExpiryBuffer = int64(1)
 
 // Recipient is an interface which describes an object capable
 // of receiving tickets
diff --git a/pm/sender.go b/pm/sender.go
index 570c3864b7..0efdf849ad 100644
--- a/pm/sender.go
+++ b/pm/sender.go
@@ -155,7 +155,9 @@ func (s *sender) validateTicketParams(ticketParams *TicketParams, numTickets int
 	}
 
 	latestBlock := s.timeManager.LastSeenBlock()
-	if ticketParams.ExpirationBlock.Cmp(latestBlock) <= 0 {
+
+	currentBuffer := new(big.Int).Sub(latestBlock, ticketParams.ExpirationBlock).Int64()
+	if currentBuffer > paramsExpiryBuffer {
 		return ErrTicketParamsExpired
 	}
 
diff --git a/pm/sender_test.go b/pm/sender_test.go
index 8217ed5106..9bd77a246a 100644
--- a/pm/sender_test.go
+++ b/pm/sender_test.go
@@ -498,13 +498,24 @@ func TestValidateTicketParams_ExpiredParams_ReturnsError(t *testing.T) {
 	sender.maxEV = big.NewRat(100, 1)
 	sender.depositMultiplier = 2
 
+	sender.timeManager.(*stubTimeManager).lastSeenBlock = big.NewInt(100)
+
 	// test expired
 	ticketParams := defaultTicketParams(t, RandAddress())
-	ticketParams.ExpirationBlock = big.NewInt(int64(-1))
+	ticketParams.ExpirationBlock = big.NewInt(int64(1))
 	err := sender.ValidateTicketParams(&ticketParams)
 	assert.EqualError(t, err, ErrTicketParamsExpired.Error())
 
+	// test within 10% of expiry
+	ticketParams.ExpirationBlock = big.NewInt(99)
+	err = sender.ValidateTicketParams(&ticketParams)
+	assert.Nil(t, err)
+
 	// test nil
+	ticketParams.ExpirationBlock = big.NewInt(105)
+	err = sender.ValidateTicketParams(&ticketParams)
+	assert.Nil(t, err)
+
 	ticketParams.ExpirationBlock = big.NewInt(0)
 	err = sender.ValidateTicketParams(&ticketParams)
 	assert.Nil(t, err)