diff --git a/CMakeLists.txt b/CMakeLists.txt
index d4a3fa4..ec99347 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -37,6 +37,8 @@ list(APPEND CSOURCES
 	src/capture_traffic.c
 	src/cap_utils.h
 	src/cap_utils.c
+	src/measure.h
+	src/measure.c
 )
 
 add_executable(donar ${CSOURCES} src/donar.c)
diff --git a/r/thunder_configure.R b/r/thunder_configure.R
index 668208a..2daf8a5 100644
--- a/r/thunder_configure.R
+++ b/r/thunder_configure.R
@@ -3,7 +3,7 @@ library(sqldf)
 library(plyr)
 library(cowplot)
 
-thunder_ms <- read.csv("thunder_23.csv")
+thunder_ms <- read.csv("thunder_22.csv")
 thunder_ms <- sqldf("select run,ident,jmax,links,latency, CAST(latency as real) / 1000. as lat_ms from thunder_ms")
 thunder_ms$links <- as.factor(thunder_ms$links)
 thunder_ms$jmax <- as.factor(thunder_ms$jmax)
@@ -61,7 +61,7 @@ thunder_bw$links <- as.factor(thunder_bw$links)
 v3 <- ggplot(data = thunder_bw, aes(x = jmax, y=sent_ratio, fill=links)) +
   geom_boxplot(outlier.size=0.1) +
   #scale_y_log10() +
-  coord_cartesian(ylim = c(1,2)) +
+  coord_cartesian(ylim = c(1,4)) +
   scale_fill_grey() +
   ylab("bandwidth ratio") +
   xlab("max allowed jitter") +
diff --git a/r/tor_owd.R b/r/tor_owd.R
new file mode 100644
index 0000000..3922804
--- /dev/null
+++ b/r/tor_owd.R
@@ -0,0 +1,20 @@
+library(ggplot2)
+library(sqldf)
+library(dplyr)
+library(cowplot)
+
+tor_owd <- read.csv("tor_owd.csv")
+
+for (run_id in c(0:39)) {
+  print(run_id)
+  sel_owd <- filter(tor_owd, measure_type != "delta", run == paste("./out/nBV7DWLpj8WA6Be3-",run_id,sep=""))
+  ggplot(data = sel_owd, aes(x = packet_id, y=latency_ms, color=measure_type)) +
+    geom_line() +
+    theme_classic() +
+    ggsave(paste("tor_owd_",run_id,".png", sep = ""), dpi=150, dev='png', height=18, width=32, units="cm")
+}
+
+ggplot(data = sqldf("select * from tor_owd where measure_type='delta_abs'"), aes(x=latency_ms)) +
+  stat_ecdf(pad = FALSE) +
+  coord_cartesian(xlim = c(0,500)) +
+  theme_classic()
diff --git a/scripts/Makefile b/scripts/Makefile
index df9cfa8..27e15c6 100644
--- a/scripts/Makefile
+++ b/scripts/Makefile
@@ -4,7 +4,15 @@ simple_test:
 	./run-3 \
 		1,simple_test . \
 		thunder-client 600 100 100 8 150 . \
-		thunder-server 8 150 . \
+		thunder-server 8 150 100. \
+		tor3 -f /etc/torrc_simple . \
+		tor3 -f /etc/torrc_simple
+
+simple_test_2:
+	./run-3 \
+		1,simple_test . \
+		orig-client 600 100 100 . \
+		orig-server 100. \
 		tor3 -f /etc/torrc_simple . \
 		tor3 -f /etc/torrc_simple
 
@@ -15,10 +23,10 @@ tor_bw_small:
 		  orig-client 120 500 100, \
 		  orig-client 600 100 100, \
 		  orig-client 1200 50 100 . \
-		orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server . \
+		orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100. \
 		tor3 -f /etc/torrc_simple, \
 		  tor3 -f /etc/torrc_simple, \
 		  tor3 -f /etc/torrc_simple, \
@@ -40,11 +48,11 @@ tor_bw_full:
 		  orig-client 6000 100 100, \
 		  orig-client 12000 50 100, \
 		  orig-client 30000 20 100 . \
-		orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server . \
+		orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100. \
 		tor3 -f /etc/torrc_simple, \
 		  tor3 -f /etc/torrc_simple, \
 		  tor3 -f /etc/torrc_simple, \
@@ -67,10 +75,10 @@ tor_guards_small:
 		  dup2-client 600 100 100 8, \
 		  dup2-client 600 100 100 8, \
 		  dup2-client 600 100 100 8 . \
-		dup2-server 8, \
-		  dup2-server 8, \
-		  dup2-server 8, \
-		  dup2-server 8 . \
+		dup2-server 8 100, \
+		  dup2-server 8 100, \
+		  dup2-server 8 100, \
+		  dup2-server 8 100. \
 		tor3 -f /etc/torrc_guard_1, \
 		  tor3 -f /etc/torrc_guard_3, \
 		  tor3 -f /etc/torrc_guard_5, \
@@ -92,15 +100,15 @@ tor_guards_full:
 		  dup2-client 6000 100 100 8, \
 		  dup2-client 6000 100 100 8, \
 		  dup2-client 6000 100 100 8 . \
-		dup2-server 8, \
-		  dup2-server 8, \
-		  dup2-server 8, \
-		  dup2-server 8, \
-		  dup2-server 8, \
-		  dup2-server 8, \
-		  dup2-server 8, \
-		  dup2-server 8, \
-		  dup2-server 8 . \
+		dup2-server 8 100, \
+		  dup2-server 8 100, \
+		  dup2-server 8 100, \
+		  dup2-server 8 100, \
+		  dup2-server 8 100, \
+		  dup2-server 8 100, \
+		  dup2-server 8 100, \
+		  dup2-server 8 100, \
+		  dup2-server 8 100. \
 		tor3 -f /etc/torrc_guard_1, \
 		  tor3 -f /etc/torrc_guard_2, \
 		  tor3 -f /etc/torrc_guard_3, \
@@ -130,9 +138,9 @@ tor_relays_full:
 		orig-client 6000 100 100, \
 		  orig-client 6000 100 100, \
 		  orig-client 6000 100 100 . \
-		orig-server, \
-		  orig-server, \
-		  orig-server-single . \
+		orig-server 100, \
+		  orig-server 100, \
+		  orig-server-single 100. \
 		tor3 -f /etc/torrc_simple, \
 		  tor2 -f /etc/torrc_simple, \
 		  tor2 -f /etc/torrc_simple . \
@@ -146,9 +154,9 @@ tor_relays_small:
 		orig-client 600 100 100, \
 		  orig-client 600 100 100, \
 		  orig-client 600 100 100 . \
-		orig-server, \
-		  orig-server, \
-		  orig-server-single . \
+		orig-server 100, \
+		  orig-server 100, \
+		  orig-server-single 100. \
 		tor3 -f /etc/torrc_simple, \
 		  tor2 -f /etc/torrc_simple, \
 		  tor2 -f /etc/torrc_simple . \
@@ -170,13 +178,13 @@ thunder_configure_small:
 		  thunder-client 600 100 100 $(link_num) 250, \
 		  thunder-client 600 100 100 $(link_num) 300, \
 		  thunder-client 600 100 100 $(link_num) 350. \
-		thunder-server $(link_num) 50, \
-		  thunder-server $(link_num) 100, \
-		  thunder-server $(link_num) 150, \
-		  thunder-server $(link_num) 200, \
-		  thunder-server $(link_num) 250, \
-		  thunder-server $(link_num) 300, \
-		  thunder-server $(link_num) 350. \
+		thunder-server $(link_num) 50 100, \
+		  thunder-server $(link_num) 100 100, \
+		  thunder-server $(link_num) 150 100, \
+		  thunder-server $(link_num) 200 100, \
+		  thunder-server $(link_num) 250 100, \
+		  thunder-server $(link_num) 300 100, \
+		  thunder-server $(link_num) 350 100. \
 		tor2 -f /etc/torrc_guard_2, \
 		  tor2 -f /etc/torrc_guard_2, \
 		  tor2 -f /etc/torrc_guard_2, \
@@ -202,13 +210,13 @@ thunder_configure_full:
 		  thunder-client 6000 100 100 $(link_num) 250, \
 		  thunder-client 6000 100 100 $(link_num) 300, \
 		  thunder-client 6000 100 100 $(link_num) 350. \
-		thunder-server $(link_num) 50, \
-		  thunder-server $(link_num) 100, \
-		  thunder-server $(link_num) 150, \
-		  thunder-server $(link_num) 200, \
-		  thunder-server $(link_num) 250, \
-		  thunder-server $(link_num) 300, \
-		  thunder-server $(link_num) 350. \
+		thunder-server $(link_num) 50 100, \
+		  thunder-server $(link_num) 100 100, \
+		  thunder-server $(link_num) 150 100, \
+		  thunder-server $(link_num) 200 100, \
+		  thunder-server $(link_num) 250 100, \
+		  thunder-server $(link_num) 300 100, \
+		  thunder-server $(link_num) 350 100. \
 		tor2 -f /etc/torrc_guard_2, \
 		  tor2 -f /etc/torrc_guard_2, \
 		  tor2 -f /etc/torrc_guard_2, \
@@ -237,12 +245,12 @@ thunder_configure_2_part:
 	    thunder-client 9900 30 100 8 ${jmax}, \
 	    thunder-client 9900 30 100 12 ${jmax}, \
 	    thunder-client 9900 30 100 16 ${jmax}. \
-	  thunder-server 2 ${jmax}, \
-	    thunder-server 4 ${jmax}, \
-	    thunder-server 6 ${jmax}, \
-	    thunder-server 8 ${jmax}, \
-	    thunder-server 12 ${jmax}, \
-	    thunder-server 16 ${jmax}. \
+	  thunder-server 2 ${jmax} 100, \
+	    thunder-server 4 ${jmax} 100, \
+	    thunder-server 6 ${jmax} 100, \
+	    thunder-server 8 ${jmax} 100, \
+	    thunder-server 12 ${jmax} 100, \
+	    thunder-server 16 ${jmax} 100. \
 	  tor2 -f /etc/torrc_simple, \
 	    tor2 -f /etc/torrc_simple, \
 	    tor2 -f /etc/torrc_simple, \
@@ -301,48 +309,48 @@ thunder_configure_2_full:
 		  thunder-client 9900 30 100 8 450, \
 		  thunder-client 9900 30 100 8 550, \
 		  thunder-client 9900 30 100 8 650. \
-		thunder-server 2 50, \
-		  thunder-server 2 150, \
-		  thunder-server 2 250, \
-		  thunder-server 2 350, \
-		  thunder-server 2 450, \
-		  thunder-server 2 550, \
-		  thunder-server 2 650, \
-		  thunder-server 4 50, \
-		  thunder-server 4 150, \
-		  thunder-server 4 250, \
-		  thunder-server 4 350, \
-		  thunder-server 4 450, \
-		  thunder-server 4 550, \
-		  thunder-server 4 650, \
-		  thunder-server 6 50, \
-		  thunder-server 6 150, \
-		  thunder-server 6 250, \
-		  thunder-server 6 350, \
-		  thunder-server 6 450, \
-		  thunder-server 6 550, \
-		  thunder-server 6 650, \
-		  thunder-server 12 50, \
-		  thunder-server 12 150, \
-		  thunder-server 12 250, \
-		  thunder-server 12 350, \
-		  thunder-server 12 450, \
-		  thunder-server 12 550, \
-		  thunder-server 12 650, \
-		  thunder-server 16 50, \
-		  thunder-server 16 150, \
-		  thunder-server 16 250, \
-		  thunder-server 16 350, \
-		  thunder-server 16 450, \
-		  thunder-server 16 550, \
-		  thunder-server 16 650, \
-		  thunder-server 8 50, \
-		  thunder-server 8 150, \
-		  thunder-server 8 250, \
-		  thunder-server 8 350, \
-		  thunder-server 8 450, \
-		  thunder-server 8 550, \
-		  thunder-server 8 650. \
+		thunder-server 2 50 100, \
+		  thunder-server 2 150 100, \
+		  thunder-server 2 250 100, \
+		  thunder-server 2 350 100, \
+		  thunder-server 2 450 100, \
+		  thunder-server 2 550 100, \
+		  thunder-server 2 650 100, \
+		  thunder-server 4 50 100, \
+		  thunder-server 4 150 100, \
+		  thunder-server 4 250 100, \
+		  thunder-server 4 350 100, \
+		  thunder-server 4 450 100, \
+		  thunder-server 4 550 100, \
+		  thunder-server 4 650 100, \
+		  thunder-server 6 50 100, \
+		  thunder-server 6 150 100, \
+		  thunder-server 6 250 100, \
+		  thunder-server 6 350 100, \
+		  thunder-server 6 450 100, \
+		  thunder-server 6 550 100, \
+		  thunder-server 6 650 100, \
+		  thunder-server 12 50 100, \
+		  thunder-server 12 150 100, \
+		  thunder-server 12 250 100, \
+		  thunder-server 12 350 100, \
+		  thunder-server 12 450 100, \
+		  thunder-server 12 550 100, \
+		  thunder-server 12 650 100, \
+		  thunder-server 16 50 100, \
+		  thunder-server 16 150 100, \
+		  thunder-server 16 250 100, \
+		  thunder-server 16 350 100, \
+		  thunder-server 16 450 100, \
+		  thunder-server 16 550 100, \
+		  thunder-server 16 650 100, \
+		  thunder-server 8 50 100, \
+		  thunder-server 8 150 100, \
+		  thunder-server 8 250 100, \
+		  thunder-server 8 350 100, \
+		  thunder-server 8 450 100, \
+		  thunder-server 8 550 100, \
+		  thunder-server 8 650 100. \
 		tor2 -f /etc/torrc_simple, \
 		  tor2 -f /etc/torrc_simple, \
 		  tor2 -f /etc/torrc_simple, \
@@ -455,86 +463,86 @@ thunder_configure_2_full_parse_red:
 tor_just_many_latencies:
 	./run-3 \
 		2,tor_just_many_latencies . \
-		orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100, \
-		  orig-client 9900 30 100 . \
-		orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server, \
-		  orig-server . \
+		orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100, \
+		  orig-client ${count} ${interval} 100 . \
+		orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100, \
+		  orig-server 100. \
 		tor3 -f /etc/torrc_simple, \
 		  tor3 -f /etc/torrc_simple, \
 		  tor3 -f /etc/torrc_simple, \
@@ -659,18 +667,18 @@ thunder_guards:
 		  thunder-client 9900 30 100 12 250, \
 		  thunder-client 9900 30 100 12 250, \
 		  thunder-client 9900 30 100 12 250. \
-		thunder-server 12 250, \
-		  thunder-server 12 250, \
-		  thunder-server 12 250, \
-		  thunder-server 12 250, \
-		  thunder-server 12 250, \
-		  thunder-server 12 250, \
-		  thunder-server 12 250, \
-		  thunder-server 12 250, \
-		  thunder-server 12 250, \
-		  thunder-server 12 250, \
-		  thunder-server 12 250, \
-		  thunder-server 12 250. \
+		thunder-server 12 250 100, \
+		  thunder-server 12 250 100, \
+		  thunder-server 12 250 100, \
+		  thunder-server 12 250 100, \
+		  thunder-server 12 250 100, \
+		  thunder-server 12 250 100, \
+		  thunder-server 12 250 100, \
+		  thunder-server 12 250 100, \
+		  thunder-server 12 250 100, \
+		  thunder-server 12 250 100, \
+		  thunder-server 12 250 100, \
+		  thunder-server 12 250 100. \
 		tor2 -f /etc/torrc_guard_2, \
 		  tor2 -f /etc/torrc_guard_4, \
 		  tor2 -f /etc/torrc_guard_6, \
diff --git a/scripts/deltams.py b/scripts/deltams.py
new file mode 100755
index 0000000..e7c0c64
--- /dev/null
+++ b/scripts/deltams.py
@@ -0,0 +1,34 @@
+#!/usr/bin/python3
+import sys,re
+
+print("run,packet_id,measure_type,latency,latency_ms")
+for i in range(1,len(sys.argv)):
+  path = sys.argv[i]
+  client_server = f"{sys.argv[i]}/log/server-measlat-stdout.log"
+  server_client = f"{sys.argv[i]}/log/client-measlat-stdout.log"
+  run = path
+
+  agg = {}
+  with open(client_server, 'r') as f:
+    for line in f:
+      res = re.match(r".*Packet (\d+) latency (\d+)µs", line)
+      if not res: continue
+      pkt_id,lat = res.groups()
+      pkt_id,lat = int(pkt_id), int(lat)
+      agg[pkt_id] = {"client_server": lat }
+
+  with open(server_client, 'r') as f:
+    for line in f:
+      res = re.match(r".*Packet (\d+) latency (\d+)µs", line)
+      if not res: continue
+      pkt_id,lat = res.groups()
+      pkt_id,lat = int(pkt_id), int(lat)
+      if not pkt_id in agg: agg[pkt_id] = {}
+      agg[pkt_id]["server_client"] = lat
+
+  for packet_id, lats in agg.items():
+    if "client_server" not in lats or "server_client" not in lats: continue
+    print(f"{run},{packet_id},client_server,{lats['client_server']},{lats['client_server'] / 1000}")
+    print(f"{run},{packet_id},server_client,{lats['server_client']},{lats['server_client'] / 1000}")
+    print(f"{run},{packet_id},delta,{lats['client_server'] - lats['server_client']},{(lats['client_server'] - lats['server_client'])/1000}")
+    print(f"{run},{packet_id},delta_abs,{abs(lats['client_server'] - lats['server_client'])},{abs(lats['client_server'] - lats['server_client'])/1000}")
diff --git a/scripts/dup2-server b/scripts/dup2-server
index 6272c17..b67b4f3 100755
--- a/scripts/dup2-server
+++ b/scripts/dup2-server
@@ -1,6 +1,6 @@
 #!/bin/bash
-mkdir -p $2/{log,shared}
-cd $2/shared
+mkdir -p $3/{log,shared}
+cd $3/shared
 
 donar \
   -a dup2 \
@@ -10,4 +10,4 @@ donar \
   -e 9000 \
 > ../log/server-donar-stdout.log 2> ../log/server-donar-stderr.log &
 
-udpecho -p 9000 > ../log/server-udpecho-stdout.log 2> ../log/server-udpecho-stderr.log
+udpecho -p 9000 -m -s $2 > ../log/server-udpecho-stdout.log 2> ../log/server-udpecho-stderr.log
diff --git a/scripts/orig-client b/scripts/orig-client
index 14e70bc..346b766 100755
--- a/scripts/orig-client
+++ b/scripts/orig-client
@@ -5,5 +5,5 @@ pushd $4/shared > /dev/null
 HS="`cat onion_services.pub | head -n1`.onion"
 popd > /dev/null
 
-measlat -h $HS -p 7500 -t tor > /dev/null 2> $4/log/client-bootstrap-stderr.log # Used to wait for connections
-measlat -h $HS -p 7500 -t tor -c $1 -i $2 -s $3 > $4/res/orig.csv 2> $4/log/client-measlat-stderr.log
+measlat -h $HS -p 7500 -t tor -r -s $3 > /dev/null 2> $4/log/client-bootstrap-stderr.log # Used to wait for connections
+measlat -h $HS -p 7500 -t tor -c $1 -i $2 -s $3 > $4/log/client-measlat-stdout.log 2> $4/log/client-measlat-stderr.log
diff --git a/scripts/orig-server b/scripts/orig-server
index dd3cbf5..d3d9f28 100755
--- a/scripts/orig-server
+++ b/scripts/orig-server
@@ -1,4 +1,4 @@
 #!/bin/bash
-mkdir -p $1/{log,shared}
-cd $1/shared
-torecho > ../log/server-udpecho-stdout.log 2> ../log/server-udpecho-stderr.log
+mkdir -p $2/{log,shared}
+cd $2/shared
+measlat -t tor -p 7500 -l -s $1 > ../log/server-measlat-stdout.log 2> ../log/server-measlat-stderr.log
diff --git a/scripts/orig-server-single b/scripts/orig-server-single
index f785c38..1284c2e 100755
--- a/scripts/orig-server-single
+++ b/scripts/orig-server-single
@@ -1,4 +1,4 @@
 #!/bin/bash
-mkdir -p $1/{log,shared}
-cd $1/shared
-torecho -n > ../log/server-udpecho-stdout.log 2> ../log/server-udpecho-stderr.log
+mkdir -p $2/{log,shared}
+cd $2/shared
+torecho -n -m -s $1 > ../log/server-udpecho-stdout.log 2> ../log/server-udpecho-stderr.log
diff --git a/scripts/thunder-client b/scripts/thunder-client
index 6705735..0f6075a 100755
--- a/scripts/thunder-client
+++ b/scripts/thunder-client
@@ -5,7 +5,7 @@ donar \
   -c \
   -o $6/shared/onion_services.pub \
   -l $4 \
-  -p jitter=$5 \
+  -p jitter=$5,scheduler=1 \
   -b \
   -r 9000 \
 > $6/log/client-donar-stdout.log 2> $6/log/client-donar-stderr.log &
diff --git a/scripts/thunder-server b/scripts/thunder-server
index e0a60e3..322c548 100755
--- a/scripts/thunder-server
+++ b/scripts/thunder-server
@@ -1,14 +1,14 @@
 #!/bin/bash
-mkdir -p $3/{log,shared}
-cd $3/shared
+mkdir -p $4/{log,shared}
+cd $4/shared
 
 donar \
   -a thunder \
   -s \
   -l $1 \
-  -p jitter=$2 \
+  -p jitter=$2,scheduler=1 \
   -b \
   -e 9000 \
 > ../log/server-donar-stdout.log 2> ../log/server-donar-stderr.log &
 
-udpecho -p 9000 > ../log/server-udpecho-stdout.log 2> ../log/server-udpecho-stderr.log
+udpecho -p 9000 -m -s $3 > ../log/server-udpecho-stdout.log 2> ../log/server-udpecho-stderr.log
diff --git a/src/meas_lat.c b/src/meas_lat.c
index 43f9c13..bfa6fce 100644
--- a/src/meas_lat.c
+++ b/src/meas_lat.c
@@ -8,138 +8,20 @@
 #include "net_tools.h"
 #include "socks5.h"
 #include "utils.h"
+#include "measure.h"
+#include "url.h"
+#include "tor_os.h"
+#include "tor_ctl.h"
 
 struct measlat_ctx {
-  int count, size, interval, verbose;
+  struct measure_conf mc;
+  struct sockaddr_in addr;
+  socklen_t addrlen;
+  int verbose, is_timer_started, is_from_needed, tor_flags;
   char *host, *port, *transport;
 };
 
-struct measure_conf {
-  uint64_t max_measure;
-  uint64_t payload_size;
-  char* payload;
-  uint64_t counter;
-};
-
-struct packet_header {
-  uint64_t counter;
-  struct timespec emit_time;
-};
-
-struct measure_conf* create_measure_conf(int max_mes, int plsize) {
-  struct measure_conf* mc = malloc(sizeof(struct measure_conf));
-  if (mc == NULL) {
-    perror("Malloc failed");
-    exit(EXIT_FAILURE);
-  }
-
-  mc->counter = 0;
-  mc->max_measure = max_mes;
-  mc->payload_size = plsize;
-  mc->payload = malloc(mc->payload_size);
-  if (mc->payload == NULL) {
-    perror("malloc failed");
-    exit(EXIT_FAILURE);
-  }
-
-  return mc;
-}
-
-void free_mesure_conf(void* v) {
-  struct measure_conf* mc = (struct measure_conf*)v;
-  free(mc->payload);
-  free(mc);
-}
-
-int on_udp_err(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
-  return 1;
-}
-
-int on_udp(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
-  ssize_t res;
-  uint64_t micro_sec;
-  struct timespec curr;
-  struct measure_conf* mc = fdinfo->other;
-  res = read(fdinfo->fd, mc->payload, mc->payload_size);
-  if (res == -1 && errno == EAGAIN) return 1;
-  if (res != mc->payload_size) {
-    perror("read error");
-    exit(EXIT_FAILURE);
-  }
-  struct packet_header* head = (struct packet_header*) mc->payload;
-  if (clock_gettime(CLOCK_MONOTONIC, &curr) == -1){
-    perror("clock_gettime error");
-    exit(EXIT_FAILURE);
-  }
-  time_t now;
-  time(&now);
-  char* ctime_no_newline = strtok(ctime(&now), "\n");
-
-  micro_sec = elapsed_micros (&head->emit_time, &curr);
-  printf("[%s] Packet %llu latency %luµs\n", ctime_no_newline, (unsigned long long)head->counter, micro_sec);
-
-  if (mc->max_measure > 0 && head->counter >= mc->max_measure) {
-    printf("Measurement done\n");
-    exit(EXIT_SUCCESS);
-  }
-  return 0;
-}
-
-void free_timer_conf(void* v) {
-  struct measure_conf* mc = v;
-  free(mc->payload);
-  free(mc);
-}
-
-int on_timer(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
-  ssize_t s;
-  uint64_t ticks = 0;
-  struct measure_conf* mc = fdinfo->other;
-
-  s = read(fdinfo->fd, &ticks, sizeof(uint64_t));
-  if (s == -1 && errno == EAGAIN) return 1;
-  if (s != sizeof(uint64_t)) {
-    perror("Read error");
-    exit(EXIT_FAILURE);
-  }
-
-  if (ticks != 1) {
-    fprintf(stderr, "Has ticked %lu times, expected 1 time. This is a bug\n", ticks);
-  }
-  mc->counter++;
-
-  memset(mc->payload, 0, mc->payload_size);
-  struct packet_header* head = (struct packet_header*)mc->payload;
-  head->counter = mc->counter;
-  if (clock_gettime(CLOCK_MONOTONIC, &head->emit_time) == -1) {
-    perror("clock_gettime error");
-    exit(EXIT_FAILURE);
-  }
-
-  char *my_msg = "Tu n'es pas tout a fait la misere,\nCar les levres les plus pauvres te denoncent\nPar un sourire.";
-  size_t msg_len = strlen(my_msg);
-  size_t cursor_msg = 0;
-  for (size_t i = sizeof(struct packet_header); i < mc->payload_size; i++) {
-    mc->payload[i] = my_msg[cursor_msg];
-    cursor_msg = (cursor_msg + 1) % msg_len;
-  }
-
-  struct evt_core_fdinfo* tgtinfo = evt_core_get_first_from_cat (ctx, "udp-read");
-  if (tgtinfo == NULL) tgtinfo = evt_core_get_first_from_cat (ctx, "tcp-read");
-  if (tgtinfo == NULL) {
-    printf("No connection yet\n");
-    return 1;
-  }
-  s = send(tgtinfo->fd, mc->payload, mc->payload_size, 0);
-  if (s < 0) {
-    perror("Send error");
-    //exit(EXIT_FAILURE);
-  }
-  return 0;
-}
-
-
-void register_timer(struct evt_core_ctx* evts, int udp, int interval, int count, int size) {
+void register_timer(struct evt_core_ctx* evts, struct timespec* next_tick) {
   struct timespec now;
   struct itimerspec timer_config;
   char url[1024];
@@ -148,16 +30,26 @@ void register_timer(struct evt_core_ctx* evts, int udp, int interval, int count,
   fdinfo.cat = &cat;
   fdinfo.url = url;
 
+  struct evt_core_cat* ucat = evt_core_get_from_cat (evts, "tcp-read");
+  if (ucat == NULL) {
+    fprintf(stderr, "Category udp-read not found\n");
+    exit(EXIT_FAILURE);
+  }
+  struct measlat_ctx* mctx = ucat->app_ctx;
+  mctx->is_timer_started = 1;
+
   if (clock_gettime(CLOCK_REALTIME, &now) == -1) {
     perror("clock_gettime");
     exit(EXIT_FAILURE);
   }
-  uint64_t micro_sec = interval;
-  timer_config.it_value.tv_sec = now.tv_sec + 1;
-  timer_config.it_value.tv_nsec = now.tv_nsec;
+  uint64_t micro_sec = mctx->mc.interval;
+  timer_config.it_value.tv_sec = next_tick == NULL ? now.tv_sec + 1 : next_tick->tv_sec;
+  timer_config.it_value.tv_nsec = next_tick == NULL ? now.tv_nsec : next_tick->tv_nsec;
   timer_config.it_interval.tv_sec = micro_sec / 1000;
   timer_config.it_interval.tv_nsec = micro_sec % 1000 * 1000000;
 
+  printf("timer_config: sec=%ld nsec=%ld \n", (uint64_t) timer_config.it_value.tv_sec, (uint64_t) timer_config.it_value.tv_nsec);
+
   fdinfo.fd = timerfd_create(CLOCK_REALTIME, 0);
   if (fdinfo.fd == -1) {
     perror("Unable to timerfd_create");
@@ -168,13 +60,123 @@ void register_timer(struct evt_core_ctx* evts, int udp, int interval, int count,
     exit(EXIT_FAILURE);
   }
   fdinfo.cat->name = "timer";
-  fdinfo.other = create_measure_conf(count, size);
-  fdinfo.free_other = free_timer_conf;
-  sprintf(fdinfo.url, "timer:%d:%d", interval, count);
+  sprintf(fdinfo.url, "timer:%ld:%ld", mctx->mc.interval, mctx->mc.max_measure);
   evt_core_add_fd (evts, &fdinfo);
   printf("--- Timer registered\n");
 }
 
+int on_receive_measure_packet_err(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
+  return 1;
+}
+
+int on_receive_measure_packet(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
+  ssize_t nread;
+  struct measlat_ctx* mctx = fdinfo->cat->app_ctx;
+
+  if (mctx->is_from_needed) nread = recvfrom(fdinfo->fd, mctx->mc.payload, mctx->mc.payload_size, MSG_TRUNC, (struct sockaddr*)&mctx->addr, &mctx->addrlen);
+  else nread = recv(fdinfo->fd, mctx->mc.payload, mctx->mc.payload_size, 0);
+
+  if ((nread == -1 && errno == EAGAIN) || nread == 0) return 1;
+  // @FIXME logic is wrong for TCP here but would lead (hopefully) to a crash
+
+  // First we parse the packet and exit if needed
+  measure_parse (nread, &mctx->mc);
+
+  // Old behaviour where we work in a RTT way and send back the packet
+  if (measure_need_reply (&mctx->mc)) {
+    ssize_t nwritten;
+    if (mctx->is_from_needed) nwritten = sendto(fdinfo->fd, mctx->mc.payload, nread, 0, (struct sockaddr*)&mctx->addr, mctx->addrlen);
+    else nwritten = send(fdinfo->fd, mctx->mc.payload, nread, 0);
+
+    // @FIXME don't support EAGAIN on write. Could be intended, you don't think so?
+    if (nwritten != nread) {
+      fprintf(stderr, "Didn't write the same number of bytes as read. nread=%ld, nwritten=%ld\n", nread, nwritten);
+      perror("write errno");
+      exit(EXIT_FAILURE);
+    }
+    return 0;
+  }
+
+  // Used to start sending from the server in sync with client
+  if (!mctx->is_timer_started) {
+    struct timespec next_tick = {0};
+    measure_next_tick(&mctx->mc, &next_tick);
+    register_timer (ctx, &next_tick);
+  }
+
+  return 0;
+}
+
+
+int on_tcp_co(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
+  int conn_sock1, conn_sock2;
+  struct sockaddr_in addr;
+  socklen_t in_len;
+  char url[1024], port[6];
+  struct evt_core_cat local_cat = {0};
+  struct evt_core_fdinfo to_fdinfo = {0};
+  to_fdinfo.cat = &local_cat;
+  to_fdinfo.url = url;
+
+  in_len = sizeof(addr);
+  conn_sock1 = accept(fdinfo->fd, (struct sockaddr*)&addr, &in_len);
+
+  if (conn_sock1 == -1 && errno == EAGAIN) return 1;
+  if (conn_sock1 == -1) goto co_error;
+
+  url_get_port(port, fdinfo->url);
+
+  to_fdinfo.fd = conn_sock1;
+  to_fdinfo.cat->name = "tcp-read";
+  sprintf(to_fdinfo.url, "tcp:read:127.0.0.1:%s", port);
+  evt_core_add_fd (ctx, &to_fdinfo);
+
+  return 0;
+
+co_error:
+  perror("Failed to handle new connection");
+  exit(EXIT_FAILURE);
+}
+
+int on_timer(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
+  ssize_t s;
+  uint64_t ticks = 0;
+  struct measlat_ctx* mctx = fdinfo->cat->app_ctx;
+
+  s = read(fdinfo->fd, &ticks, sizeof(uint64_t));
+  if (s == -1 && errno == EAGAIN) return 1;
+  if (s != sizeof(uint64_t)) {
+    perror("Read error");
+    exit(EXIT_FAILURE);
+  }
+
+  if (ticks != 1) {
+    fprintf(stderr, "Has ticked %lu times, expected 1 time. This is a bug\n", ticks);
+  }
+
+  struct measure_packet* head = measure_generate(&mctx->mc);
+  //printf("send(id=%ld,is_echo=%d)\n", head->counter, head->is_echo);
+
+  struct evt_core_fdinfo* tgtinfo = evt_core_get_first_from_cat (ctx, "udp-read");
+  if (tgtinfo == NULL) tgtinfo = evt_core_get_first_from_cat (ctx, "tcp-read");
+  if (tgtinfo == NULL) {
+    printf("No connection yet\n");
+    struct evt_core_fdinfo* timer_fd = evt_core_get_first_from_cat (ctx, "timer");
+    evt_core_rm_fd(ctx, timer_fd->fd);
+    mctx->is_timer_started = 0;
+    return 1;
+  }
+  if (mctx->is_from_needed) s = sendto(tgtinfo->fd, mctx->mc.payload, mctx->mc.payload_size, 0, (struct sockaddr*)&mctx->addr, mctx->addrlen);
+  else s = send(tgtinfo->fd, mctx->mc.payload, mctx->mc.payload_size, 0);
+
+  if (s < 0) {
+    perror("Send error");
+    //exit(EXIT_FAILURE);
+  }
+
+  return 0;
+}
+
 int on_socks5_success_measlat(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
   char url[1024];
   struct evt_core_cat cat = {0};
@@ -192,18 +194,16 @@ int on_socks5_success_measlat(struct evt_core_ctx* ctx, struct evt_core_fdinfo*
 
   fdinfo_n.fd = dup(fdinfo->fd);
   fdinfo_n.cat->name = "tcp-read";
-  fdinfo_n.other = create_measure_conf (mctx->count, mctx->size);
-  fdinfo_n.free_other = free_mesure_conf;
   sprintf(fdinfo_n.url, "tcp:read:%s:%d", s5ctx->addr, s5ctx->port);
 
   evt_core_add_fd (ctx, &fdinfo_n);
   printf("--- Tor socket registered\n");
 
-  register_timer(ctx, fdinfo->fd, mctx->interval, mctx->count, mctx->size);
+  register_timer(ctx, NULL);
   return 1;
 }
 
-void spawn_tor_socket(struct evt_core_ctx* evts) {
+void spawn_tor_client(struct evt_core_ctx* evts) {
   struct evt_core_cat* ucat = evt_core_get_from_cat (evts, "tcp-read");
   if (ucat == NULL) {
     fprintf(stderr, "Category udp-read not found\n");
@@ -212,11 +212,12 @@ void spawn_tor_socket(struct evt_core_ctx* evts) {
   struct measlat_ctx* mctx = ucat->app_ctx;
 
   socks5_create_dns_client (evts, "127.0.0.1", "9050", mctx->host, atoi(mctx->port));
+  printf("--- Tor client SOCKS started\n");
 }
 
 int on_socks5_failed_measlat(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
   evt_core_rm_fd (ctx, fdinfo->fd);
-  spawn_tor_socket(ctx);
+  spawn_tor_client(ctx);
 
   return 1;
 }
@@ -231,18 +232,24 @@ void register_categories(struct evt_core_ctx* evts, struct measlat_ctx* mctx) {
   template.flags = EPOLLIN | EPOLLET;
   evt_core_add_cat(evts, &template);
 
-  template.cb = on_udp; // intended but not elegant
-  template.err_cb = on_udp_err; // intended but not elegant
+  template.cb = on_receive_measure_packet; // intended but not elegant
+  template.err_cb = NULL; // intended but not elegant
   template.name = "tcp-read";
   template.flags = EPOLLIN | EPOLLET;
   evt_core_add_cat(evts, &template);
 
-  template.cb = on_udp;
-  template.err_cb = on_udp_err;
+  template.cb = on_receive_measure_packet;
+  template.err_cb = on_receive_measure_packet_err;
   template.name = "udp-read";
   template.flags = EPOLLIN | EPOLLET;
   evt_core_add_cat(evts, &template);
 
+  template.cb = on_tcp_co;
+  template.err_cb = NULL;
+  template.name = "tcp-co";
+  template.flags = EPOLLIN | EPOLLET;
+  evt_core_add_cat(evts, &template);
+
   template.cb = on_socks5_success_measlat;
   template.err_cb = on_socks5_failed_measlat;
   template.name = "socks5-success";
@@ -260,7 +267,7 @@ void register_categories(struct evt_core_ctx* evts, struct measlat_ctx* mctx) {
 
 }
 
-void spawn_udp_socket(struct evt_core_ctx* evts) {
+void spawn_udp_client(struct evt_core_ctx* evts) {
   struct evt_core_cat* ucat = evt_core_get_from_cat (evts, "udp-read");
   if (ucat == NULL) {
     fprintf(stderr, "Category udp-read not found\n");
@@ -277,13 +284,72 @@ void spawn_udp_socket(struct evt_core_ctx* evts) {
 
   fdinfo.fd = udp_sock;
   fdinfo.cat->name = "udp-read";
-  fdinfo.other = create_measure_conf (mctx->count, mctx->size);
-  fdinfo.free_other = free_mesure_conf;
+  fdinfo.other = &mctx->mc;
+  fdinfo.free_other = NULL;
   sprintf(fdinfo.url, "udp:read:%s:%s", mctx->host, mctx->port);
   evt_core_add_fd (evts, &fdinfo);
-  printf("--- UDP socket registered\n");
+  printf("--- UDP client registered\n");
 
-  register_timer(evts, fdinfo.fd, mctx->interval, mctx->count, mctx->size);
+  register_timer(evts, NULL);
+}
+
+void spawn_udp_server(struct evt_core_ctx* evts) {
+  struct evt_core_cat* ucat = evt_core_get_from_cat (evts, "udp-read");
+  if (ucat == NULL) {
+    fprintf(stderr, "Category udp-read not found\n");
+    exit(EXIT_FAILURE);
+  }
+  struct measlat_ctx* mctx = ucat->app_ctx;
+  int udp_sock = create_udp_server (mctx->host, mctx->port);
+
+  char url[1024];
+  struct evt_core_cat cat = {0};
+  struct evt_core_fdinfo fdinfo = {0};
+  fdinfo.cat = &cat;
+  fdinfo.url = url;
+
+  fdinfo.fd = udp_sock;
+  sprintf(url, "udp:rw:127.0.0.1:%s", mctx->port);
+  fdinfo.cat->name = "udp-read";
+  evt_core_add_fd(evts, &fdinfo);
+  printf("--- UDP server is listening\n");
+}
+
+void spawn_tor_server(struct evt_core_ctx* evts, uint16_t *ports) {
+  char buffer[1024];
+  int tcp_serv_sock, err;
+
+  sprintf(buffer, "%d", ports[0]);
+  tcp_serv_sock = create_tcp_server ("0.0.0.0", buffer);
+  err = listen(tcp_serv_sock, SOMAXCONN);
+
+  struct evt_core_cat cat = {0};
+  struct evt_core_fdinfo fdinfo = {0};
+  fdinfo.cat = &cat;
+  fdinfo.url = buffer;
+
+  fdinfo.fd = tcp_serv_sock;
+  sprintf(buffer, "tcp:co:127.0.0.1:%d", ports[0]);
+  fdinfo.cat->name = "tcp-co";
+  evt_core_add_fd(evts, &fdinfo);
+  printf("--- TCP server is listening\n");
+}
+
+void measlat_create_onion_services(struct tor_os_str* tos, struct tor_ctl* tctl, uint16_t* ports, int ports_count, enum TOR_ONION_FLAGS tof) {
+    tor_os_create (tos, "onion_services.pub", "onion_services.txt", ports_count);
+    tor_os_read (tos);
+
+    int err = 0;
+    err = tor_ctl_connect (tctl, "127.0.0.1", "9051");
+    if (err < 0) {
+      fprintf(stderr, "Unable to open Tor Socket\n");
+      exit(EXIT_FAILURE);
+    }
+    err = tor_ctl_add_onion (tctl, tos, ports, tof);
+    if (err != 0) {
+      fprintf(stderr, "Unable to create Onion Services (error: %d)\n", err);
+      exit(EXIT_FAILURE);
+    }
 }
 
 int main(int argc, char** argv) {
@@ -295,7 +361,7 @@ int main(int argc, char** argv) {
   struct evt_core_ctx evts = {0};
 
   // 1. Parse parameters
-  while ((opt = getopt(argc, argv, "vh:p:c:s:i:t:")) != -1) {
+  while ((opt = getopt(argc, argv, "vh:p:c:s:i:t:lrn")) != -1) {
       switch(opt) {
       case 'v':
         mctx.verbose++;
@@ -306,17 +372,26 @@ int main(int argc, char** argv) {
       case 'p': // port
         mctx.port = optarg;
         break;
+      case 'l':
+        mctx.mc.is_server = 1;
+        break;
       case 't': // transport
         mctx.transport = optarg;
         break;
       case 'c': // count
-        mctx.count = atoi(optarg);
+        mctx.mc.max_measure = atoi(optarg);
         break;
       case 's': // size - payload in bytes
-        mctx.size = atoi(optarg);
+        mctx.mc.payload_size = atoi(optarg);
+        break;
+      case 'r':
+        mctx.mc.is_rtt = 1;
+        break;
+      case 'n':
+        mctx.tor_flags |= TOR_ONION_FLAG_NON_ANONYMOUS;
         break;
       case 'i': // interval - every ms
-        mctx.interval = atoi(optarg);
+        mctx.mc.interval = atoi(optarg);
         break;
       default:
         goto usage;
@@ -324,25 +399,41 @@ int main(int argc, char** argv) {
   }
 
   // 2. Check and fix parameters
-  size_t header_size = sizeof(struct packet_header);
-  if (mctx.interval <= 0) mctx.interval = 1000;
-  if (mctx.count <= 0) mctx.count = 1;
-  if (mctx.size < header_size) mctx.size = header_size;
+  measure_prepare (&mctx.mc);
+  mctx.addrlen = sizeof(mctx.addr);
   if (mctx.transport == NULL) mctx.transport = "udp";
-  if (mctx.host == NULL || mctx.port == NULL) goto usage;
-  printf("[measlat_conf] host=%s, port=%s, transport=%s, count=%d, size=%d, interval=%d\n",
-          mctx.host, mctx.port, mctx.transport, mctx.count, mctx.size, mctx.interval);
+  if (mctx.host == NULL) mctx.host = "127.0.0.1";
+  if (mctx.port == NULL) mctx.port = strcmp(mctx.transport, "udp") == 0 ? "9000" : "7500";
+  printf("[measlat_conf] host=%s, port=%s, listen=%d, transport=%s, count=%ld, size=%ld, interval=%ld, is_rtt=%d\n",
+          mctx.host, mctx.port, mctx.mc.is_server, mctx.transport, mctx.mc.max_measure, mctx.mc.payload_size, mctx.mc.interval, mctx.mc.is_rtt);
 
   // 3. Bind events
   register_categories(&evts, &mctx);
-  if (strcmp(mctx.transport, "udp") == 0) spawn_udp_socket(&evts);
-  else if (strcmp(mctx.transport, "tor") == 0) spawn_tor_socket(&evts);
+
+  struct tor_os_str tos = {0};
+  struct tor_ctl tctl = {0};
+  uint16_t ports[] = {7500};
+  int ports_count = sizeof(ports) / sizeof(ports[0]);
+
+  if (mctx.mc.is_server && strcmp(mctx.transport, "udp") == 0) {
+    spawn_udp_server (&evts);
+    mctx.is_from_needed = 1;
+
+  }
+  else if (mctx.mc.is_server && strcmp(mctx.transport, "tor") == 0) {
+    spawn_tor_server(&evts, ports);
+    measlat_create_onion_services (&tos, &tctl, ports, ports_count, mctx.tor_flags);
+    printf("--- Onion services created\n");
+  }
+  else if (strcmp(mctx.transport, "udp") == 0) spawn_udp_client(&evts);
+  else if (strcmp(mctx.transport, "tor") == 0) spawn_tor_client(&evts);
+  else exit(EXIT_FAILURE);
 
   // 4. Run main loop
   evt_core_loop(&evts);
 
   return 0;
 usage:
-  fprintf(stderr, "Usage: %s -h <host> -p <port> [-t <udp|tor>] [-c <count>] [-i <ms>] [-s <bytes>]\n", argv[0]);
+  fprintf(stderr, "Usage: %s -h <host> -p <port> [-l] [-r] [-t <udp|tor>] [-c <count>] [-i <ms>] [-s <bytes>]\n", argv[0]);
   exit(EXIT_FAILURE);
 }
diff --git a/src/measure.c b/src/measure.c
new file mode 100644
index 0000000..e7d1fb2
--- /dev/null
+++ b/src/measure.c
@@ -0,0 +1,93 @@
+#include "measure.h"
+#define ONE_SEC 1000000000L
+
+void measure_parse(int size, struct measure_conf* mc) {
+  struct timespec curr;
+  uint64_t micro_sec;
+  if (size != mc->payload_size) {
+    perror("read error");
+    exit(EXIT_FAILURE);
+  }
+  struct measure_packet* head = (struct measure_packet*) mc->payload;
+  if (clock_gettime(CLOCK_REALTIME, &curr) == -1){
+    perror("clock_gettime error");
+    exit(EXIT_FAILURE);
+  }
+  time_t now;
+  time(&now);
+  char* ctime_no_newline = strtok(ctime(&now), "\n");
+
+  micro_sec = elapsed_micros (&head->emit_time, &curr);
+  printf("[%s] Packet %llu latency %luµs\n", ctime_no_newline, (unsigned long long)head->counter, micro_sec);
+
+  if (!mc->is_server && head->counter >= mc->max_measure) {
+    printf("Measurement done\n");
+    exit(EXIT_SUCCESS);
+  }
+}
+
+void measure_prepare(struct measure_conf* mc) {
+  if (mc->interval <= 0) mc->interval = 1000;
+  if (mc->max_measure <= 0) mc->max_measure = 1;
+  if (mc->payload_size < sizeof(struct measure_packet)) mc->payload_size = sizeof(struct measure_packet);
+
+  if ((mc->payload = malloc(sizeof(char) * mc->payload_size)) == NULL) {
+    perror("payload malloc failed");
+    exit(EXIT_FAILURE);
+  }
+  memset(mc->payload, 0, mc->payload_size);
+
+  char *my_msg = "Tu n'es pas tout a fait la misere,\nCar les levres les plus pauvres te denoncent\nPar un sourire.";
+  size_t msg_len = strlen(my_msg);
+  size_t cursor_msg = 0;
+  for (size_t i = sizeof(struct measure_packet); i < mc->payload_size; i++) {
+    mc->payload[i] = my_msg[cursor_msg];
+    cursor_msg = (cursor_msg + 1) % msg_len;
+  }
+}
+struct measure_packet* measure_generate(struct measure_conf* mc) {
+  struct measure_packet* head = (struct measure_packet*)mc->payload;
+  mc->counter++;
+
+  head->counter = mc->counter;
+  head->is_echo = mc->is_rtt && !mc->is_server;
+  if (clock_gettime(CLOCK_REALTIME, &head->emit_time) == -1) {
+    perror("clock_gettime error");
+    exit(EXIT_FAILURE);
+  }
+  return head;
+}
+
+uint8_t timespec_gt(struct timespec *t1, struct timespec *t2) {
+  return t1->tv_sec > t2->tv_sec || (t1->tv_sec == t2->tv_sec && t1->tv_nsec > t2->tv_nsec);
+}
+
+void measure_next_tick(struct measure_conf *mc, struct timespec *next) {
+  struct measure_packet *head = (struct measure_packet*) mc->payload;
+  struct timespec now, *sent_at = &head->emit_time;
+  mc->counter = head->counter;
+
+  if (clock_gettime(CLOCK_REALTIME, &now) == -1) {
+    perror("clock_gettime error");
+    exit(EXIT_FAILURE);
+  }
+  memcpy(next, sent_at, sizeof(struct timespec));
+
+  while(!timespec_gt (next, &now)) {
+    next->tv_nsec += mc->interval * 1000000L;
+    if (next->tv_nsec > ONE_SEC) {
+      next->tv_sec += next->tv_nsec / ONE_SEC;
+      next->tv_nsec = next->tv_nsec % ONE_SEC;
+    }
+    mc->counter++;
+  }
+  mc->counter--;
+  printf("interval: %ld\n", mc->interval);
+  printf("sent_at: sec=%ld nsec=%ld \n", (uint64_t) sent_at->tv_sec, (uint64_t) sent_at->tv_nsec);
+  printf("now: sec=%ld nsec=%ld \n", (uint64_t) now.tv_sec, (uint64_t) now.tv_nsec);
+  printf("next: sec=%ld nsec=%ld \n", (uint64_t) next->tv_sec, (uint64_t) next->tv_nsec);
+}
+
+uint8_t measure_need_reply(struct measure_conf* mc) {
+  return mc->is_server && ((struct measure_packet*)mc->payload)->is_echo;
+};
diff --git a/src/measure.h b/src/measure.h
new file mode 100644
index 0000000..72a53f8
--- /dev/null
+++ b/src/measure.h
@@ -0,0 +1,28 @@
+#pragma once
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdint.h>
+#include <time.h>
+#include <string.h>
+#include "utils.h"
+
+struct measure_conf {
+  uint64_t max_measure;
+  uint64_t payload_size;
+  uint64_t interval;
+  char* payload;
+  uint64_t counter;
+  uint8_t is_server, is_rtt;
+};
+
+struct measure_packet {
+  uint64_t counter;
+  uint8_t is_echo;
+  struct timespec emit_time;
+};
+
+void measure_parse(int size, struct measure_conf* mc);
+void measure_prepare(struct measure_conf* mc);
+struct measure_packet* measure_generate(struct measure_conf* mc);
+uint8_t measure_need_reply(struct measure_conf* mc);
+void measure_next_tick(struct measure_conf *mc, struct timespec *next);
diff --git a/src/tor_echo.c b/src/tor_echo.c
index f015ece..7c33600 100644
--- a/src/tor_echo.c
+++ b/src/tor_echo.c
@@ -6,6 +6,12 @@
 #include "evt_core.h"
 #include "net_tools.h"
 #include "url.h"
+#include "measure.h"
+
+struct torecho_ctx {
+  uint8_t is_measlat;
+  struct measure_conf mc;
+};
 
 void te_create_onion_services(struct tor_os_str* tos, struct tor_ctl* tctl, uint16_t* ports, int ports_count, enum TOR_ONION_FLAGS tof) {
     tor_os_create (tos, "onion_services.pub", "onion_services.txt", ports_count);
@@ -55,21 +61,23 @@ co_error:
 }
 
 int te_on_tcp(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
-  char buffer[1500];
   ssize_t nread, nwritten;
   struct sockaddr_in addr;
   socklen_t addrlen = sizeof(addr);
+  struct torecho_ctx *tctx = fdinfo->cat->app_ctx;
 
-  nread = recv(fdinfo->fd, buffer, sizeof(buffer), 0);
+  nread = recv(fdinfo->fd, tctx->mc.payload, tctx->mc.payload_size, 0);
   if (nread == -1 && errno == EAGAIN) return 1; // Read done
   if (nread == 0) { fprintf(stderr, "WARN! Read 0 bytes.\n"); return 1; }
-  if (nread < 0 || nread > sizeof(buffer)) {
-    fprintf(stderr, "Message is either truncated or an error occured. nread=%ld\n", nread);
+  if (nread < 0 || nread > tctx->mc.payload_size) {
+    fprintf(stderr, "Message is either truncated or an error occured. nread=%ld, expected=%ld\n", nread, tctx->mc.payload_size);
     perror("read errno");
     exit(EXIT_FAILURE);
   }
 
-  nwritten = send(fdinfo->fd, buffer, nread, 0);
+  if (tctx->is_measlat) measure_parse (nread, &tctx->mc);
+
+  nwritten = send(fdinfo->fd, tctx->mc.payload, nread, 0);
   // @FIXME don't support EAGAIN on write. Could be intended, you don't think so?
   if (nwritten != nread) {
     fprintf(stderr, "Didn't write the same number of bytes as read - not supported. nread=%ld, nwritten=%ld\n", nread, nwritten);
@@ -91,13 +99,21 @@ int main(int argc, char** argv) {
   struct tor_ctl tctl;
   enum TOR_ONION_FLAGS tof = TOR_ONION_FLAG_NONE;
   char url[1024];
+  struct torecho_ctx tctx = {0};
+  tctx.mc.is_server = 1;
+  tctx.mc.payload_size = 1500;
 
-
-  while ((opt = getopt(argc, argv, "n")) != -1) {
+  while ((opt = getopt(argc, argv, "ns:m")) != -1) {
       switch(opt) {
       case 'n':
         tof |= TOR_ONION_FLAG_NON_ANONYMOUS;
         break;
+      case 'm':
+        tctx.is_measlat = 1;
+        break;
+      case 's':
+        tctx.mc.payload_size = atoi(optarg);
+        break;
       default:
         break;
       }
@@ -105,7 +121,7 @@ int main(int argc, char** argv) {
 
   // 1. Register categories
   struct evt_core_cat tcp_co = {
-    .app_ctx = NULL,
+    .app_ctx = &tctx,
     .free_app_ctx = NULL,
     .cb = te_on_tcp_co,
     .err_cb = NULL,
@@ -114,7 +130,7 @@ int main(int argc, char** argv) {
     .socklist = NULL
   };
   struct evt_core_cat tcp_all = {
-    .app_ctx = NULL,
+    .app_ctx = &tctx  ,
     .free_app_ctx = NULL,
     .cb = te_on_tcp,
     .err_cb = NULL,
@@ -122,6 +138,8 @@ int main(int argc, char** argv) {
     .flags = EPOLLIN | EPOLLOUT | EPOLLET | EPOLLRDHUP,
     .socklist = NULL
   };
+  measure_prepare (&tctx.mc);
+
   evt_core_init(&evts, 0);
   evt_core_add_cat(&evts, &tcp_co);
   evt_core_add_cat(&evts, &tcp_all);
diff --git a/src/udp_echo.c b/src/udp_echo.c
index df887cc..92f3e34 100644
--- a/src/udp_echo.c
+++ b/src/udp_echo.c
@@ -4,22 +4,30 @@
 #include <errno.h>
 #include "evt_core.h"
 #include "net_tools.h"
+#include "measure.h"
+
+struct udpecho_ctx {
+  struct measure_conf mc;
+  uint8_t is_measlat;
+};
 
 int on_udp(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
-  char buffer[1500];
   ssize_t nread, nwritten;
   struct sockaddr_in addr;
   socklen_t addrlen = sizeof(addr);
+  struct udpecho_ctx *uctx = fdinfo->cat->app_ctx;
 
-  nread = recvfrom(fdinfo->fd, buffer, sizeof(buffer), MSG_TRUNC, (struct sockaddr*)&addr, &addrlen);
+  nread = recvfrom(fdinfo->fd, uctx->mc.payload, uctx->mc.payload_size, MSG_TRUNC, (struct sockaddr*)&addr, &addrlen);
   if (nread == -1 && errno == EAGAIN) return 1; // Read done
-  if (nread <= 0 || nread > sizeof(buffer)) {
-    fprintf(stderr, "Message is either truncated or an error occured. nread=%ld\n", nread);
+  if (nread <= 0 || nread > uctx->mc.payload_size) {
+    fprintf(stderr, "Message is either truncated or an error occured. nread=%ld, expected=%ld\n", nread, uctx->mc.payload_size);
     perror("read errno");
     exit(EXIT_FAILURE);
   }
 
-  nwritten = sendto(fdinfo->fd, buffer, nread, 0, (struct sockaddr*)&addr, addrlen);
+  if (uctx->is_measlat) measure_parse (nread, &uctx->mc);
+
+  nwritten = sendto(fdinfo->fd, uctx->mc.payload, nread, 0, (struct sockaddr*)&addr, addrlen);
   // @FIXME don't support EAGAIN on write. Could be intended, you don't think so?
   if (nwritten != nread) {
     fprintf(stderr, "Didn't write the same number of bytes as read. nread=%ld, nwritten=%ld\n", nread, nwritten);
@@ -33,12 +41,15 @@ int main(int argc, char** argv) {
   setvbuf(stdout, NULL, _IONBF, 0);
   printf("~ udpecho ~\n");
 
+  struct udpecho_ctx uctx = {0};
   int opt, udp_sock, verbose = 0;
   char *port = NULL, *bindhost = NULL;
   struct evt_core_ctx evts = {0};
+  uctx.mc.is_server = 1;
+  uctx.mc.payload_size = 1500;
 
   // 1. Parse parameters
-  while ((opt = getopt(argc, argv, "b:p:v")) != -1) {
+  while ((opt = getopt(argc, argv, "b:p:vms:")) != -1) {
       switch(opt) {
       case 'v':
         verbose++;
@@ -49,15 +60,22 @@ int main(int argc, char** argv) {
       case 'b':
         bindhost = optarg;
         break;
+      case 'm':
+        uctx.is_measlat = 1;
+        break;
+      case 's':
+        uctx.mc.payload_size = atoi(optarg);
+        break;
       default:
         goto usage;
       }
   }
   if (bindhost == NULL) bindhost = "127.0.0.1";
+  measure_prepare (&uctx.mc);
 
   // 2. Register category
   struct evt_core_cat udp_read = {
-    .app_ctx = NULL,
+    .app_ctx = &uctx,
     .free_app_ctx = NULL,
     .cb = on_udp,
     .err_cb = NULL,