From: fxlb <fx.lebail@yahoo.com>
Date: Thu, 25 Apr 2013 15:44:14 +0000 (+0200)
Subject: DHCPv6 decoder update
X-Git-Tag: tcpdump-4.5.0~87^2
X-Git-Url: https://git.tcpdump.org/tcpdump/commitdiff_plain/af7a65c643c8025b6f1e83d4556c9fcf4ac46b4d?hp=5937079df9d8bf0865b8db9fac9603327fa87d1d

DHCPv6 decoder update
- Rename option 31 as SNTP_SERVERS (see RFC4075)
- Add decoder for option 56 (NTP_SERVER) from RFC5908
---

diff --git a/print-dhcp6.c b/print-dhcp6.c
index 35de278d..9bfe6e70 100644
--- a/print-dhcp6.c
+++ b/print-dhcp6.c
@@ -36,6 +36,7 @@
  *  RFC4075: Simple Network Time Protocol (SNTP) Configuration option,
  *  RFC4242: Information Refresh Time option,
  *  RFC4280: Broadcast and Multicast Control Servers options,
+ *  RFC5908: Network Time Protocol (NTP) Server Option for DHCPv6
  *  RFC6334: Dual-Stack Lite option,
  */
 
@@ -154,7 +155,7 @@ struct dhcp6_relay {
 #define DH6OPT_NISP_SERVERS 28
 #define DH6OPT_NIS_NAME 29
 #define DH6OPT_NISP_NAME 30
-#define DH6OPT_NTP_SERVERS 31
+#define DH6OPT_SNTP_SERVERS 31
 #define DH6OPT_LIFETIME 32
 #define DH6OPT_BCMCS_SERVER_D 33
 #define DH6OPT_BCMCS_SERVER_A 34
@@ -171,6 +172,10 @@ struct dhcp6_relay {
 #define DH6OPT_CLT_TIME 46
 #define DH6OPT_LQ_RELAY_DATA 47
 #define DH6OPT_LQ_CLIENT_LINK 48
+#define DH6OPT_NTP_SERVER 56
+#  define DH6OPT_NTP_SUBOPTION_SRV_ADDR 1
+#  define DH6OPT_NTP_SUBOPTION_MC_ADDR 2
+#  define DH6OPT_NTP_SUBOPTION_SRV_FQDN 3
 #define DH6OPT_AFTR_NAME 64
 
 struct dhcp6opt {
@@ -238,8 +243,8 @@ dhcp6opt_name(int type)
 		return "IA_PD";
 	case DH6OPT_IA_PD_PREFIX:
 		return "IA_PD-prefix";
-	case DH6OPT_NTP_SERVERS:
-		return "NTP-server";
+	case DH6OPT_SNTP_SERVERS:
+		return "SNTP-servers";
 	case DH6OPT_LIFETIME:
 		return "lifetime";
 	case DH6OPT_NIS_SERVERS:
@@ -280,6 +285,8 @@ dhcp6opt_name(int type)
 		return "LQ-relay-data";
 	case DH6OPT_LQ_CLIENT_LINK:
 		return "LQ-client-link";
+	case DH6OPT_NTP_SERVER:
+		return "NTP-server";
 	case DH6OPT_AFTR_NAME:
 		return "AFTR-Name";
 	default:
@@ -337,6 +344,8 @@ dhcp6opt_print(const u_char *cp, const u_char *ep)
 	u_int authinfolen, authrealmlen;
 	int remain_len;  /* Length of remaining options */
 	int label_len;   /* Label length */
+	u_int16_t subopt_code;
+	u_int16_t subopt_len;
 
 	if (cp == ep)
 		return;
@@ -581,7 +590,7 @@ dhcp6opt_print(const u_char *cp, const u_char *ep)
 			break;
 		case DH6OPT_SIP_SERVER_A:
 		case DH6OPT_DNS:
-		case DH6OPT_NTP_SERVERS:
+		case DH6OPT_SNTP_SERVERS:
 		case DH6OPT_NIS_SERVERS:
 		case DH6OPT_NISP_SERVERS:
 		case DH6OPT_BCMCS_SERVER_A:
@@ -719,6 +728,40 @@ dhcp6opt_print(const u_char *cp, const u_char *ep)
 				printf("%02x", tp[i]);
 			printf("...)");
 			break;
+		case DH6OPT_NTP_SERVER:
+			if (optlen < 4) {
+				printf(" ?)");
+				break;
+			}
+			tp = (u_char *)(dh6o + 1);
+			while (tp < ep - 4) {
+				subopt_code = EXTRACT_16BITS(tp);
+				tp += 2;
+				subopt_len = EXTRACT_16BITS(tp);
+				tp += 2;
+				printf(" subopt:%d", subopt_code);
+				switch (subopt_code) {
+				case DH6OPT_NTP_SUBOPTION_SRV_ADDR:
+				case DH6OPT_NTP_SUBOPTION_MC_ADDR:
+					if (subopt_len != 16) {
+						printf(" ?");
+						break;
+					}
+					printf(" %s", ip6addr_string(&tp[0]));
+					tp += subopt_len;
+					break;
+				case DH6OPT_NTP_SUBOPTION_SRV_FQDN:
+					putchar(' ');
+					ns_nprint(tp, ep);
+					tp += subopt_len;
+					break;
+				default:
+					printf(" ?");
+					break;
+				}
+			}
+			printf(")");
+			break;
 		case DH6OPT_AFTR_NAME:
 			if (optlen < 3) {
 				printf(" ?)");
diff --git a/tests/TESTLIST b/tests/TESTLIST
index fc6bcb90..2e2f74db 100644
--- a/tests/TESTLIST
+++ b/tests/TESTLIST
@@ -88,6 +88,7 @@ dhcpv6-aftr-name	dhcpv6-AFTR-Name-RFC6334.pcap	dhcpv6-AFTR-Name-RFC6334.out	-t -
 dhcpv6-ia-na	dhcpv6-ia-na.pcap	dhcpv6-ia-na.out	-t -v
 dhcpv6-ia-pd	dhcpv6-ia-pd.pcap	dhcpv6-ia-pd.out	-t -v
 dhcpv6-ia-ta	dhcpv6-ia-ta.pcap	dhcpv6-ia-ta.out	-t -v
+dhcpv6-ntp-server	dhcpv6-ntp-server.pcap	dhcpv6-ntp-server.out	-t -v
 
 # ZeroMQ/PGM tests
 # ZMTP/1.0 over TCP
diff --git a/tests/dhcpv6-ntp-server.out b/tests/dhcpv6-ntp-server.out
new file mode 100644
index 00000000..23db5bd6
--- /dev/null
+++ b/tests/dhcpv6-ntp-server.out
@@ -0,0 +1 @@
+IP6 (hlim 64, next-header UDP (17) payload length: 113) fe80::20c:29ff:fe9b:a15d.547 > fe80::20c:29ff:fe38:f368.546: [udp sum ok] dhcp6 reply (xid=f69b57 (client-ID hwaddr/time type 1 time 418384703 000c2938f368) (server-ID hwaddr/time type 1 time 418354459 000c299ba153) (NTP-server subopt:1 2a01::1 subopt:2 ff05::101 subopt:3 ntp.example.com.))
diff --git a/tests/dhcpv6-ntp-server.pcap b/tests/dhcpv6-ntp-server.pcap
new file mode 100644
index 00000000..5657692e
Binary files /dev/null and b/tests/dhcpv6-ntp-server.pcap differ