diff --git a/README.md b/README.md
index a6ec95bb775e77a392c9fd113a48968fd2fc9e5e..1ba2207a813504c1c7987e3021a85541d6661f5d 100644
--- a/README.md
+++ b/README.md
@@ -24,7 +24,7 @@ sudo cp packetdrill /usr/bin
 ### Linux (Ubuntu)
 For installing the required packages run:
 ```
-sudo apt-get install make git libsctp-dev bison flex
+sudo apt-get install make git libsctp-dev bison flex python
 ```
 Then download the sources, compile them and install the binary:
 ```
@@ -37,7 +37,7 @@ sudo cp packetdrill /usr/bin
 ### FreeBSD
 For installing the required packages run:
 ```
-sudo pkg install git bison
+sudo pkg install git bison python
 ```
 Then download the sources, compile them and install the binary:
 ```
diff --git a/gtests/net/packetdrill/tests/linux/sctp/api_tests/cmsgs/sendmsg_sctp_init.pkt b/gtests/net/packetdrill/tests/linux/sctp/api_tests/cmsgs/sendmsg_sctp_init.pkt
index 3f00c4ffc186061ffb6f0119af85be933bdf8a79..d87f6a972ca2a4e4950a31eb550c175181cbcf54 100644
--- a/gtests/net/packetdrill/tests/linux/sctp/api_tests/cmsgs/sendmsg_sctp_init.pkt
+++ b/gtests/net/packetdrill/tests/linux/sctp/api_tests/cmsgs/sendmsg_sctp_init.pkt
@@ -8,7 +8,7 @@
 
 +0.0 sendmsg(3, {msg_name(...)=...,
 		 msg_iov(1)=[{iov_base=..., iov_len=1000}],
-		 msg_control(20)=[{cmsg_len=20,
+		 msg_control(24)=[{cmsg_len=24,
 				   cmsg_level=IPPROTO_SCTP,
 				   cmsg_type=SCTP_INIT,
 				   cmsg_data={sinit_num_ostreams=1,
diff --git a/gtests/net/packetdrill/tests/linux/sctp/api_tests/cmsgs/sendmsg_sctp_sndrcv.pkt b/gtests/net/packetdrill/tests/linux/sctp/api_tests/cmsgs/sendmsg_sctp_sndrcv.pkt
index 9f57a3ca70a6f4a10d5c200f59783b3eda7548c2..a67602a4e69d850df352eae99acb1abbaa9ac90d 100644
--- a/gtests/net/packetdrill/tests/linux/sctp/api_tests/cmsgs/sendmsg_sctp_sndrcv.pkt
+++ b/gtests/net/packetdrill/tests/linux/sctp/api_tests/cmsgs/sendmsg_sctp_sndrcv.pkt
@@ -25,7 +25,7 @@
 							 spp_dscp=0}, 152) = 0
 +0.0 sendmsg(3, {msg_name(...)=...,
 		 msg_iov(1)=[{iov_base=..., iov_len=1000}],
-		 msg_control(44)=[{cmsg_len=44,
+		 msg_control(48)=[{cmsg_len=48,
 				    cmsg_level=IPPROTO_SCTP,
 				    cmsg_type=SCTP_SNDRCV,
 				    cmsg_data={sinfo_stream=3,
@@ -44,7 +44,7 @@
 //test for sndrcvinfo
 +0.0 sendmsg(3, {msg_name(...)=...,
 		 msg_iov(1)=[{iov_base=..., iov_len=1000}],
-		 msg_control(44)=[{cmsg_len=44,
+		 msg_control(48)=[{cmsg_len=48,
 				    cmsg_level=IPPROTO_SCTP,
 				    cmsg_type=SCTP_SNDRCV,
 				    cmsg_data={sinfo_stream=3,
@@ -62,7 +62,7 @@
 
 +0.0 sendmsg(3, {msg_name(...)=...,
 		 msg_iov(1)=[{iov_base=..., iov_len=1000}],
-		 msg_control(44)=[{cmsg_len=44,
+		 msg_control(48)=[{cmsg_len=48,
 				    cmsg_level=IPPROTO_SCTP,
 				    cmsg_type=SCTP_SNDRCV,
 				    cmsg_data={sinfo_stream=3,
@@ -80,7 +80,7 @@
 
 +0.0 sendmsg(3, {msg_name(...)=...,
 		 msg_iov(1)=[{iov_base=..., iov_len=1000}],
-		 msg_control(44)=[{cmsg_len=44,
+		 msg_control(48)=[{cmsg_len=48,
 				    cmsg_level=IPPROTO_SCTP,
 				    cmsg_type=SCTP_SNDRCV,
 				    cmsg_data={sinfo_stream=3,
diff --git a/gtests/net/packetdrill/tests/linux/sctp/api_tests/getsockopt/sctp_primary_addr.pkt b/gtests/net/packetdrill/tests/linux/sctp/api_tests/getsockopt/sctp_primary_addr.pkt
index db160a48f491c9541e8f87a8b8af24035b05e340..f9e07d847fba63e805f4457d50b77f991fe0c5ce 100644
--- a/gtests/net/packetdrill/tests/linux/sctp/api_tests/getsockopt/sctp_primary_addr.pkt
+++ b/gtests/net/packetdrill/tests/linux/sctp/api_tests/getsockopt/sctp_primary_addr.pkt
@@ -13,19 +13,19 @@
 +0 setsockopt(3, IPPROTO_SCTP, SCTP_PRIMARY_ADDR, {ssp_assoc_id=...,
 						   ssp_addr={sa_family=AF_INET,
 							     sin_port=htons(8080),
-							     sin_addr=inet_addr("192.0.2.1")}}, 136) = 0
+							     sin_addr=inet_addr("192.0.2.1")}}, 132) = 0
 +0 getsockopt(3, IPPROTO_SCTP, SCTP_PRIMARY_ADDR, {ssp_assoc_id=...,
 						   ssp_addr={sa_family=AF_INET,
 						   sin_port=htons(8080),
-						   sin_addr=inet_addr("192.0.2.1")}}, [136]) = 0
+						   sin_addr=inet_addr("192.0.2.1")}}, [132]) = 0
 +0 getsockopt(3, IPPROTO_SCTP, SCTP_PRIMARY_ADDR, {ssp_assoc_id=...,
-						   ssp_addr=...}, [136]) = 0
+						   ssp_addr=...}, [132]) = 0
 
 +0 setsockopt(3, IPPROTO_SCTP, SCTP_PRIMARY_ADDR, {ssp_addr={sa_family=AF_INET,
 							     sin_port=htons(8080),
-							     sin_addr=inet_addr("192.0.2.1")}}, 136) = 0
+							     sin_addr=inet_addr("192.0.2.1")}}, 132) = 0
 +0 getsockopt(3, IPPROTO_SCTP, SCTP_PRIMARY_ADDR, {ssp_addr={sa_family=AF_INET,
 						   sin_port=htons(8080),
-						   sin_addr=inet_addr("192.0.2.1")}}, [136]) = 0
+						   sin_addr=inet_addr("192.0.2.1")}}, [132]) = 0
 
 +0 close(3) = 0