diff --git a/gtests/net/packetdrill/packet_to_string_test.c b/gtests/net/packetdrill/packet_to_string_test.c
index 4774f7ed30dab34395652e13d702877500aef44e..965395bae2e9ff27ecb703cf672be34a29648bc9 100644
--- a/gtests/net/packetdrill/packet_to_string_test.c
+++ b/gtests/net/packetdrill/packet_to_string_test.c
@@ -307,7 +307,7 @@ static void test_sctp_ipv6_packet_to_string(void)
 		     "SUPPORTED_ADDRESS_TYPES[types=[IPv4, IPv6, HOSTNAME]], "
 		     "ECN_CAPABLE[], "
 		     "FORWARD_TSN_SUPPORTED[], "
-		     "SUPPORTED_EXTENSIONS[types=[I-DATA]], "
+		     "SUPPORTED_EXTENSIONS[types=[I_DATA]], "
 		     "PAD[len=12, val=...]]; "
 		"INIT_ACK[flgs=0x00, tag=1, a_rwnd=65536, os=15, is=15, tsn=16909060, "
 			 "STATE_COOKIE[len=7, val=...], "
@@ -370,7 +370,7 @@ static void test_sctp_ipv6_packet_to_string(void)
 		     "SUPPORTED_ADDRESS_TYPES[types=[IPv4, IPv6, HOSTNAME]], "
 		     "ECN_CAPABLE[], "
 		     "FORWARD_TSN_SUPPORTED[], "
-		     "SUPPORTED_EXTENSIONS[types=[I-DATA]], "
+		     "SUPPORTED_EXTENSIONS[types=[I_DATA]], "
 		     "PAD[len=12, val=...]]; "
 		"INIT_ACK[flgs=0x00, tag=1, a_rwnd=65536, os=15, is=15, tsn=16909060, "
 			 "STATE_COOKIE[len=7, val=...], "
@@ -433,7 +433,7 @@ static void test_sctp_ipv6_packet_to_string(void)
 		     "SUPPORTED_ADDRESS_TYPES[types=[IPv4, IPv6, HOSTNAME]], "
 		     "ECN_CAPABLE[], "
 		     "FORWARD_TSN_SUPPORTED[], "
-		     "SUPPORTED_EXTENSIONS[types=[I-DATA]], "
+		     "SUPPORTED_EXTENSIONS[types=[I_DATA]], "
 		     "PAD[len=12, val=...]]; "
 		"INIT_ACK[flgs=0x00, tag=1, a_rwnd=65536, os=15, is=15, tsn=16909060, "
 			 "STATE_COOKIE[len=7, val=...], "
diff --git a/gtests/net/packetdrill/sctp.h b/gtests/net/packetdrill/sctp.h
index e8d0650b5cdd220bb22306feecd143fc7bde5a64..48476f18e2f79e88496d1f1424d22ff98e3d3e86 100644
--- a/gtests/net/packetdrill/sctp.h
+++ b/gtests/net/packetdrill/sctp.h
@@ -41,7 +41,6 @@ struct sctp_common_header {
 #define SCTP_INIT_CHUNK_TYPE				0x01
 #define SCTP_INIT_ACK_CHUNK_TYPE			0x02
 #define SCTP_SACK_CHUNK_TYPE				0x03
-#define SCTP_NR_SACK_CHUNK_TYPE				0x10
 #define SCTP_HEARTBEAT_CHUNK_TYPE			0x04
 #define SCTP_HEARTBEAT_ACK_CHUNK_TYPE			0x05
 #define SCTP_ABORT_CHUNK_TYPE				0x06
@@ -53,11 +52,12 @@ struct sctp_common_header {
 #define SCTP_ECNE_CHUNK_TYPE				0x0c
 #define SCTP_CWR_CHUNK_TYPE				0x0d
 #define SCTP_SHUTDOWN_COMPLETE_CHUNK_TYPE		0x0e
+#define SCTP_NR_SACK_CHUNK_TYPE				0x10
 #define SCTP_I_DATA_CHUNK_TYPE				0x40
 #define SCTP_RECONFIG_CHUNK_TYPE			0x82
 #define SCTP_PAD_CHUNK_TYPE				0x84
-#define SCTP_FORWARD_TSN_CHUNK_TYPE                     0xc0
-#define SCTP_I_FORWARD_TSN_CHUNK_TYPE                   0xc2
+#define SCTP_FORWARD_TSN_CHUNK_TYPE			0xc0
+#define SCTP_I_FORWARD_TSN_CHUNK_TYPE			0xc2
 
 
 #define MAX_SCTP_CHUNK_BYTES	0xffff
diff --git a/gtests/net/packetdrill/sctp_chunk_to_string.c b/gtests/net/packetdrill/sctp_chunk_to_string.c
index 51b8c217640d55267c1ac379e6b9cac104ca075a..f9738d975c82114badfab18a1b51cdd1bcb8fe64 100644
--- a/gtests/net/packetdrill/sctp_chunk_to_string.c
+++ b/gtests/net/packetdrill/sctp_chunk_to_string.c
@@ -263,19 +263,16 @@ static int sctp_supported_extensions_parameter_to_string(
 			fputs("INIT", s);
 			break;
 		case SCTP_INIT_ACK_CHUNK_TYPE:
-			fputs("INIT-ACK", s);
+			fputs("INIT_ACK", s);
 			break;
 		case SCTP_SACK_CHUNK_TYPE:
 			fputs("SACK", s);
 			break;
-		case SCTP_NR_SACK_CHUNK_TYPE:
-			fputs("NR-SACK", s);
-			break;
 		case SCTP_HEARTBEAT_CHUNK_TYPE:
 			fputs("HEARTBEAT", s);
 			break;
 		case SCTP_HEARTBEAT_ACK_CHUNK_TYPE:
-			fputs("HEARTBEAT-ACK", s);
+			fputs("HEARTBEAT_ACK", s);
 			break;
 		case SCTP_ABORT_CHUNK_TYPE:
 			fputs("ABORT", s);
@@ -284,16 +281,16 @@ static int sctp_supported_extensions_parameter_to_string(
 			fputs("SHUTDOWN", s);
 			break;
 		case SCTP_SHUTDOWN_ACK_CHUNK_TYPE:
-			fputs("SHUTDOWN-ACK", s);
+			fputs("SHUTDOWN_ACK", s);
 			break;
 		case SCTP_ERROR_CHUNK_TYPE:
 			fputs("ERROR", s);
 			break;
 		case SCTP_COOKIE_ECHO_CHUNK_TYPE:
-			fputs("COOKIE-ECHO", s);
+			fputs("COOKIE_ECHO", s);
 			break;
 		case SCTP_COOKIE_ACK_CHUNK_TYPE:
-			fputs("COOKIE-ACK", s);
+			fputs("COOKIE_ACK", s);
 			break;
 		case SCTP_ECNE_CHUNK_TYPE:
 			fputs("ECNE", s);
@@ -302,16 +299,25 @@ static int sctp_supported_extensions_parameter_to_string(
 			fputs("CWR", s);
 			break;
 		case SCTP_SHUTDOWN_COMPLETE_CHUNK_TYPE:
-			fputs("SHUTDOWN-COMPLETE", s);
+			fputs("SHUTDOWN_COMPLETE", s);
+			break;
+		case SCTP_NR_SACK_CHUNK_TYPE:
+			fputs("NR_SACK", s);
 			break;
 		case SCTP_I_DATA_CHUNK_TYPE:
-			fputs("I-DATA", s);
+			fputs("I_DATA", s);
+			break;
+		case SCTP_RECONFIG_CHUNK_TYPE:
+			fputs("RECONFIG", s);
 			break;
 		case SCTP_PAD_CHUNK_TYPE:
 			fputs("PAD", s);
 			break;
-		case SCTP_RECONFIG_CHUNK_TYPE:
-			fputs("RECONFIG", s);
+		case SCTP_FORWARD_TSN_CHUNK_TYPE:
+			fputs("FORWARD_TSN", s);
+			break;
+		case SCTP_I_FORWARD_TSN_CHUNK_TYPE:
+			fputs("I_FORWARD_TSN", s);
 			break;
 		default:
 			fprintf(s, "0x%02x", parameter->chunk_type[i]);