DHCPv6: Don't limit the hex dumps to 10 characters with -vv or more

Change the type of optlen from uint16_t to u_int to avoid:
./print-dhcp6.c: In function 'dhcp6opt_print':
./print-dhcp6.c:698:31: warning: comparison of integer expressions of
different signedness: 'u_int' {aka 'unsigned int'} and 'int'
[-Wsign-compare]
  698 |                         if (i < optlen - 4)
      |                               ^
./print-dhcp6.c:752:31: warning: comparison of integer expressions of
different signedness: 'u_int' {aka 'unsigned int'} and 'int'
[-Wsign-compare]
  752 |                         if (i < optlen - 16)
      |                               ^

Add a test with -vv option, from an existing pcap.
Update a test output accordingly.

Author: fxlb

print-dhcp6.c

@@ -287,7 +287,7 @@ dhcp6opt_print(netdissect_options *ndo,
 	const u_char *tp;
 	u_int i;
 	uint16_t opttype;
-	uint16_t optlen;
+	u_int optlen;
 	uint8_t auth_proto;
 	uint8_t auth_alg;
 	uint8_t auth_rdm;
@@ -299,6 +299,7 @@ dhcp6opt_print(netdissect_options *ndo,
 	uint8_t dh6_reconf_type;
 	uint8_t dh6_lq_query_type;
 	u_int first_list_value;
+	u_int max_char;
 
 	if (cp == ep)
 		return;
@@ -549,13 +550,16 @@ dhcp6opt_print(netdissect_options *ndo,
 			break;
 		case DH6OPT_INTERFACE_ID:
 		case DH6OPT_SUBSCRIBER_ID:
-			/*
-			 * Since we cannot predict the encoding, print hex dump
-			 * at most 10 characters.
-			 */
 			tp = (const u_char *)(dh6o + 1);
 			ND_PRINT(" ");
-			for (i = 0; i < optlen && i < 10; i++)
+			/*
+			 * if ndo_vflag < 2, print hex dump up to 10 characters.
+			 */
+			if (ndo->ndo_vflag < 2)
+				max_char = ND_MIN(optlen, 10);
+			else
+				max_char = optlen;
+			for (i = 0; i < max_char; i++)
 				ND_PRINT("%02x", GET_U_1(tp + i));
 			if (i < optlen)
 				ND_PRINT("...");
@@ -681,12 +685,17 @@ dhcp6opt_print(netdissect_options *ndo,
 			}
 			tp = (const u_char *)(dh6o + 1);
 			ND_PRINT(" enterprise %u ", GET_BE_U_4(tp));
+			tp += 4;
 			/*
-			 * Print hex dump first 10 characters.
+			 * if ndo_vflag < 2, print hex dump up to 10 characters.
 			 */
-			for (i = 4; i < optlen && i < 14; i++)
+			if (ndo->ndo_vflag < 2)
+				max_char = ND_MIN(optlen - 4, 10);
+			else
+				max_char = optlen - 4;
+			for (i = 0; i < max_char; i++)
 				ND_PRINT("%02x", GET_U_1(tp + i));
-			if (i < optlen)
+			if (i < optlen - 4)
 				ND_PRINT("...");
 			ND_PRINT(")");
 			break;
@@ -730,12 +739,17 @@ dhcp6opt_print(netdissect_options *ndo,
 			}
 			tp = (const u_char *)(dh6o + 1);
 			ND_PRINT(" %s ", GET_IP6ADDR_STRING(tp));
+			tp += 16;
 			/*
-			 * Print hex dump first 10 characters.
+			 * if ndo_vflag < 2, print hex dump up to 10 characters.
 			 */
-			for (i = 16; i < optlen && i < 26; i++)
+			if (ndo->ndo_vflag < 2)
+				max_char = ND_MIN(optlen - 16, 10);
+			else
+				max_char = optlen - 16;
+			for (i = 0; i < max_char; i++)
 				ND_PRINT("%02x", GET_U_1(tp + i));
-			if (i < optlen)
+			if (i < optlen - 16)
 				ND_PRINT("...");
 			ND_PRINT(")");
 			break;
@@ -870,7 +884,15 @@ dhcp6opt_print(netdissect_options *ndo,
 				}
 				if (subopt_len > 0) {
 					ND_PRINT(" data ");
-					for (i = 0; i < subopt_len && i < 10; i++)
+					/*
+					 * if ndo_vflag < 2, print hex dump up
+					 * to 10 characters.
+					 */
+					if (ndo->ndo_vflag < 2)
+						max_char = ND_MIN(subopt_len, 10);
+					else
+						max_char = subopt_len;
+					for (i = 0; i < max_char; i++)
 						ND_PRINT("%02x",
 							 GET_U_1(tp + i));
 					if (i < subopt_len)

tests/TESTLIST

@@ -266,6 +266,7 @@ dhcpv6-domain-list	dhcpv6-domain-list.pcap	dhcpv6-domain-list.out	-v
 dhcpv6-mud	dhcpv6-mud.pcap		dhcpv6-mud.out -v
 dhcpv6-rfc6355-duid-uuid dhcpv6-rfc6355-duid-uuid.pcap dhcpv6-rfc6355-duid-uuid.out -v
 dhcpv6-vendor-specific-information dhcpv6-vendor-specific-information.pcap dhcpv6-vendor-specific-information.out -v
+dhcpv6-vendor-specific-information-vv dhcpv6-vendor-specific-information.pcap dhcpv6-vendor-specific-information-vv.out -vv
 
 # ZeroMQ/PGM tests
 # ZMTP/1.0 over TCP

tests/dhcpv4v6-rfc5970-rfc8572.out

@@ -73,4 +73,4 @@
    11  14:15:33.148466 IP6 (flowlabel 0x1570c, hlim 64, next-header UDP (17) payload length: 157) fe80::40d3:61ff:fe62:3810.547 > fe80::200:1ff:fe01:0.546: [udp sum ok] dhcp6 advertise (xid=654242 (IA_NA IAID:16842752 T1:0 T2:0 (IA_ADDR 1234:5678::4 pltime:18000 vltime:28800)) (client-ID hwaddr/time type 1 time 701792102 000001010000) (server-ID hwaddr/time type 1 time 701792110 42d361623810) (Bootfile-URL my-startup-config) (DNS-search-list aristanetworks.com.) (DNS-server 1234:5678::2))
    12  14:15:34.152941 IP6 (flowlabel 0x03f85, hlim 1, next-header UDP (17) payload length: 126) fe80::200:1ff:fe01:0.546 > ff02::1:2.547: [udp sum ok] dhcp6 request (xid=becafa (vendor-specific-info enterprise 30065 (code 1 len 6 data 417269737461))) (client-ID hwaddr/time type 1 time 701792102 000001010000) (server-ID hwaddr/time type 1 time 701792110 42d361623810) (option-request Bootfile-URL DNS-search-list DNS-server) (elapsed-time 0) (IA_NA IAID:16842752 T1:3600 T2:5400 (IA_ADDR 1234:5678::4 pltime:7200 vltime:7500)))
    13  14:15:34.156427 IP6 (flowlabel 0x1570c, hlim 64, next-header UDP (17) payload length: 157) fe80::40d3:61ff:fe62:3810.547 > fe80::200:1ff:fe01:0.546: [udp sum ok] dhcp6 reply (xid=becafa (IA_NA IAID:16842752 T1:0 T2:0 (IA_ADDR 1234:5678::4 pltime:7200 vltime:28800)) (client-ID hwaddr/time type 1 time 701792102 000001010000) (server-ID hwaddr/time type 1 time 701792110 42d361623810) (Bootfile-URL my-startup-config) (DNS-search-list aristanetworks.com.) (DNS-server 1234:5678::2))
-   14  08:08:32.009292 IP6 (flowlabel 0x09903, hlim 1, next-header UDP (17) payload length: 138) fe80::200:44ff:fe01:0.546 > ff02::1:2.547: [udp sum ok] dhcp6 inf-req (xid=b5fcf (vendor-specific-info enterprise 30065 (code 1 len 44 data 4172697374613b546573...))) (client-ID hwaddr type 1 000044010000) (option-request Bootfile-URL DNS-search-list DNS-server) (elapsed-time 331) (user-class Arista;Test-Dhcpv6Discover;4.21.XX))
+   14  08:08:32.009292 IP6 (flowlabel 0x09903, hlim 1, next-header UDP (17) payload length: 138) fe80::200:44ff:fe01:0.546 > ff02::1:2.547: [udp sum ok] dhcp6 inf-req (xid=b5fcf (vendor-specific-info enterprise 30065 (code 1 len 44 data 4172697374613b546573742d446863707636446973636f7665723b30312e30303b4853483134343235313438))) (client-ID hwaddr type 1 000044010000) (option-request Bootfile-URL DNS-search-list DNS-server) (elapsed-time 331) (user-class Arista;Test-Dhcpv6Discover;4.21.XX))

tests/dhcpv6-vendor-specific-information-vv.out

@@ -0,0 +1 @@
+    1  23:25:55.136477 IP6 (hlim 64, next-header UDP (17) payload length: 595) fc00:502:411:1::1.546 > fc00:502:400:0:10:32:0:69.547: [udp sum ok] dhcp6 relay-fwd (linkaddr=fc00:502:411:1::1 peeraddr=fc00:502:411:1::1 (interface-ID 54d46ffa109a) (vendor-specific-info enterprise 4491 (code 38 len 4 data 01020300)) (code 39 len 6 data 54d46ffa109a))) (relay-message (dhcp6 request (xid=d98c5d (reconfigure-accept) (vendor-class) (option-request vendor-specific-info) (vendor-specific-info enterprise 4491 (code 1 len 16 data 00200021002200250026087a087b0027)) (code 2 len 3 data 45434d)) (code 3 len 12 data 45434d3a454d54413a455053)) (code 4 len 10 data 445247373930382d3533)) (code 5 len 3 data 312e30)) (code 6 len 26 data 647267373930382d5031352d31342d7633303272313231313161)) (code 7 len 5 data 322e332e31)) (code 8 len 6 data 353444343646)) (code 9 len 7 data 44524737393038)) (code 10 len 5 data 436973636f)) (code 35 len 122 data 057801010102010303010104010105010106010107010f0801100901000a01010b01180c01010d0200400e02000a0f010110040000000611010014010015013f1601011701011801041901041a01041b01201c01021d01081e01201f0110200110210102220101230100240100250101260200ff270101280100)) (code 36 len 6 data 54d46ffa109a))) (client-ID hwaddr type 1 54d46ffa109a) (server-ID hwaddr/time type 1 time 336091266 000c290f1c3b) (IA_NA IAID:1878659226 T1:0 T2:0 (IA_ADDR fc00:502:411:1::31 pltime:27000 vltime:43200) (vendor-specific-info enterprise 4491 (code 32 len 16 data fc000502040000000010003200000069)) (code 2170 len 16 data 000200040a200045000100040a200045)) (code 3 len 4 data 00000001)) (code 37 len 16 data fc000502040000000010003200000069)) (code 38 len 4 data 00000000)) (code 33 len 13 data 73616d706c65636d362e62696e)) (code 34 len 16 data fc000502040000000010003200000069)))) (elapsed-time 0))))