1*5d4cadefSSoham Chakradeo// SPDX-License-Identifier: GPL-2.0 2*5d4cadefSSoham Chakradeo// Test RFC 3042 "Limited Transmit": "sending a new data segment in 3*5d4cadefSSoham Chakradeo// response to each of the first two duplicate acknowledgments that 4*5d4cadefSSoham Chakradeo// arrive at the sender". 5*5d4cadefSSoham Chakradeo// This variation tests a receiver that supports SACK. 6*5d4cadefSSoham Chakradeo 7*5d4cadefSSoham Chakradeo`./defaults.sh` 8*5d4cadefSSoham Chakradeo 9*5d4cadefSSoham Chakradeo// Establish a connection. 10*5d4cadefSSoham Chakradeo 0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 11*5d4cadefSSoham Chakradeo +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 12*5d4cadefSSoham Chakradeo +0 bind(3, ..., ...) = 0 13*5d4cadefSSoham Chakradeo +0 listen(3, 1) = 0 14*5d4cadefSSoham Chakradeo 15*5d4cadefSSoham Chakradeo +.1 < S 0:0(0) win 32792 <mss 1000,sackOK,nop,nop,nop,wscale 7> 16*5d4cadefSSoham Chakradeo +0 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 8> 17*5d4cadefSSoham Chakradeo +.1 < . 1:1(0) ack 1 win 320 18*5d4cadefSSoham Chakradeo +0 accept(3, ..., ...) = 4 19*5d4cadefSSoham Chakradeo 20*5d4cadefSSoham Chakradeo// Write some data, and send the initial congestion window. 21*5d4cadefSSoham Chakradeo +0 write(4, ..., 15000) = 15000 22*5d4cadefSSoham Chakradeo +0 > P. 1:10001(10000) ack 1 23*5d4cadefSSoham Chakradeo 24*5d4cadefSSoham Chakradeo// Limited transmit: on first dupack, send a new data segment. 25*5d4cadefSSoham Chakradeo +.11 < . 1:1(0) ack 1 win 320 <sack 1001:2001,nop,nop> 26*5d4cadefSSoham Chakradeo +0 > . 10001:11001(1000) ack 1 27*5d4cadefSSoham Chakradeo 28*5d4cadefSSoham Chakradeo// Limited transmit: on second dupack, send a new data segment. 29*5d4cadefSSoham Chakradeo +.01 < . 1:1(0) ack 1 win 320 <sack 1001:3001,nop,nop> 30*5d4cadefSSoham Chakradeo +0 > . 11001:12001(1000) ack 1 31*5d4cadefSSoham Chakradeo 32*5d4cadefSSoham Chakradeo// It turned out to be reordering, not loss. 33*5d4cadefSSoham Chakradeo +.01 < . 1:1(0) ack 3001 win 320 34*5d4cadefSSoham Chakradeo +0 > P. 12001:14001(2000) ack 1 35*5d4cadefSSoham Chakradeo 36*5d4cadefSSoham Chakradeo +.02 < . 1:1(0) ack 5001 win 320 37*5d4cadefSSoham Chakradeo +0 > P. 14001:15001(1000) ack 1 38*5d4cadefSSoham Chakradeo 39*5d4cadefSSoham Chakradeo// Client gradually ACKs all data. 40*5d4cadefSSoham Chakradeo +.02 < . 1:1(0) ack 7001 win 320 41*5d4cadefSSoham Chakradeo +.02 < . 1:1(0) ack 9001 win 320 42*5d4cadefSSoham Chakradeo +.02 < . 1:1(0) ack 11001 win 320 43*5d4cadefSSoham Chakradeo +.02 < . 1:1(0) ack 13001 win 320 44*5d4cadefSSoham Chakradeo +.02 < . 1:1(0) ack 15001 win 320 45*5d4cadefSSoham Chakradeo 46*5d4cadefSSoham Chakradeo// Clean up. 47*5d4cadefSSoham Chakradeo +.17 close(4) = 0 48*5d4cadefSSoham Chakradeo +0 > F. 15001:15001(0) ack 1 49*5d4cadefSSoham Chakradeo +.1 < F. 1:1(0) ack 15002 win 257 50*5d4cadefSSoham Chakradeo +0 > . 15002:15002(0) ack 2 51