Fix unit test with assumed congestion avoidance

test_tcp_fast_rexmit_wraparound correctness relied on the congestion
window being in congestion avoidance so that only a single TCP_MSS
segment is sent upon ACKing the first segment.

It's not known whether the test was relying tcp_alloc() to set ssthresh
to 0 and thus start in congestion avoidance or if the test was working by
accident until changes in b90a54f989

This fixes the test by enforcing the requirement of starting in
congestion avoidance

Signed-off-by: goldsimon <goldsimon@gmx.de>
(cherry picked from commit 8bf402fd67)
This commit is contained in:
Joel Cunningham 2017-03-09 16:40:54 -06:00 committed by goldsimon
parent 0381849624
commit c31bd404e2

View File

@ -422,6 +422,8 @@ START_TEST(test_tcp_fast_rexmit_wraparound)
pcb->mss = TCP_MSS; pcb->mss = TCP_MSS;
/* disable initial congestion window (we don't send a SYN here...) */ /* disable initial congestion window (we don't send a SYN here...) */
pcb->cwnd = 2*TCP_MSS; pcb->cwnd = 2*TCP_MSS;
/* start in congestion advoidance */
pcb->ssthresh = pcb->cwnd;
/* send 6 mss-sized segments */ /* send 6 mss-sized segments */
for (i = 0; i < 6; i++) { for (i = 0; i < 6; i++) {
@ -442,7 +444,9 @@ START_TEST(test_tcp_fast_rexmit_wraparound)
/* ACK the first segment */ /* ACK the first segment */
p = tcp_create_rx_segment(pcb, NULL, 0, 0, TCP_MSS, TCP_ACK); p = tcp_create_rx_segment(pcb, NULL, 0, 0, TCP_MSS, TCP_ACK);
test_tcp_input(p, &netif); test_tcp_input(p, &netif);
/* ensure this didn't trigger a retransmission */ /* ensure this didn't trigger a retransmission. Only one
segment should be transmitted because cwnd opened up by
TCP_MSS and a fraction since we are in congestion avoidance */
EXPECT(txcounters.num_tx_calls == 1); EXPECT(txcounters.num_tx_calls == 1);
EXPECT(txcounters.num_tx_bytes == TCP_MSS + 40U); EXPECT(txcounters.num_tx_bytes == TCP_MSS + 40U);
memset(&txcounters, 0, sizeof(txcounters)); memset(&txcounters, 0, sizeof(txcounters));