// Test that a bare ACK does not complete a connection when TCP_DEFER_ACCEPT // timeout is not hit but an ACK w/ data does complete and deliver the // connection to the accept queue. 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 +0 setsockopt(3, SOL_TCP, TCP_DEFER_ACCEPT, [5], 4) = 0 +0.000 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0 +0 bind(3, ..., ...) = 0 // Set backlog to 1 so that we can easily test. +0 listen(3, 1) = 0 // Establish a connection without timestamps. +0.0 < S 0:0(0) win 32792 <mss 1460,sackOK,nop,nop,nop,wscale 7> +0.0 > S. 0:0(0) ack 1 <...> // Send a bare ACK this should not complete the connection as we // set the TCP_DEFER_ACCEPT above. +0.0 < . 1:1(0) ack 1 win 257 // The bare ACK should be dropped and no connection should be delivered // to the accept queue. +0.100 accept(3, ..., ...) = -1 EWOULDBLOCK (operation would block) // Send another bare ACK and it should still fail we set TCP_DEFER_ACCEPT // to 5 seconds above. +2.5 < . 1:1(0) ack 1 win 257 +0.100 accept(3, ..., ...) = -1 EWOULDBLOCK (operation would block) // set accept socket back to blocking. +0.000 fcntl(3, F_SETFL, O_RDWR) = 0 // Now send an ACK w/ data. This should complete the connection // and deliver the socket to the accept queue. +0.1 < . 1:5(4) ack 1 win 257 +0.0 > . 1:1(0) ack 5 <...> // This should cause connection to transition to connected state. +0.000 accept(3, ..., ...) = 4 +0.000 fcntl(4, F_SETFL, O_RDWR|O_NONBLOCK) = 0 // Now read the data and we should get 4 bytes. +0.000 read(4,..., 4) = 4 +0.000 close(4) = 0 +0.0 > F. 1:1(0) ack 5 <...> +0.0 < F. 5:5(0) ack 2 win 257 +0.01 > . 2:2(0) ack 6 <...>