+/* sub-option qualifiers */
+#define TELQUAL_IS 0 /* option is... */
+#define TELQUAL_SEND 1 /* send option */
+#define TELQUAL_INFO 2 /* ENVIRON: informational version of IS */
+#define TELQUAL_REPLY 2 /* AUTHENTICATION: client version of IS */
+#define TELQUAL_NAME 3 /* AUTHENTICATION: client version of IS */
+
+#define LFLOW_OFF 0 /* Disable remote flow control */
+#define LFLOW_ON 1 /* Enable remote flow control */
+#define LFLOW_RESTART_ANY 2 /* Restart output on any char */
+#define LFLOW_RESTART_XON 3 /* Restart output only on XON */
+
+/*
+ * LINEMODE suboptions
+ */
+
+#define LM_MODE 1
+#define LM_FORWARDMASK 2
+#define LM_SLC 3
+
+#define MODE_EDIT 0x01
+#define MODE_TRAPSIG 0x02
+#define MODE_ACK 0x04
+#define MODE_SOFT_TAB 0x08
+#define MODE_LIT_ECHO 0x10
+
+#define MODE_MASK 0x1f
+
+#define SLC_SYNCH 1
+#define SLC_BRK 2
+#define SLC_IP 3
+#define SLC_AO 4
+#define SLC_AYT 5
+#define SLC_EOR 6
+#define SLC_ABORT 7
+#define SLC_EOF 8
+#define SLC_SUSP 9
+#define SLC_EC 10
+#define SLC_EL 11
+#define SLC_EW 12
+#define SLC_RP 13
+#define SLC_LNEXT 14
+#define SLC_XON 15
+#define SLC_XOFF 16
+#define SLC_FORW1 17
+#define SLC_FORW2 18
+#define SLC_MCL 19
+#define SLC_MCR 20
+#define SLC_MCWL 21
+#define SLC_MCWR 22
+#define SLC_MCBOL 23
+#define SLC_MCEOL 24
+#define SLC_INSRT 25
+#define SLC_OVER 26
+#define SLC_ECR 27
+#define SLC_EWR 28
+#define SLC_EBOL 29
+#define SLC_EEOL 30
+
+#define NSLC 30
+
+/*
+ * For backwards compatibility, we define SLC_NAMES to be the
+ * list of names if SLC_NAMES is not defined.
+ */
+#define SLC_NAMELIST "0", "SYNCH", "BRK", "IP", "AO", "AYT", "EOR", \
+ "ABORT", "EOF", "SUSP", "EC", "EL", "EW", "RP", \
+ "LNEXT", "XON", "XOFF", "FORW1", "FORW2", \
+ "MCL", "MCR", "MCWL", "MCWR", "MCBOL", \
+ "MCEOL", "INSRT", "OVER", "ECR", "EWR", \
+ "EBOL", "EEOL", \
+ 0,
+
+#ifdef SLC_NAMES
+const char *slc_names[] = {
+ SLC_NAMELIST
+};
+#else
+extern char *slc_names[];
+#define SLC_NAMES SLC_NAMELIST
+#endif
+
+#define SLC_NAME_OK(x) ((unsigned int)(x) <= NSLC)
+#define SLC_NAME(x) slc_names[x]
+
+#define SLC_NOSUPPORT 0
+#define SLC_CANTCHANGE 1
+#define SLC_VARIABLE 2
+#define SLC_DEFAULT 3
+#define SLC_LEVELBITS 0x03
+
+#define SLC_FUNC 0
+#define SLC_FLAGS 1
+#define SLC_VALUE 2
+
+#define SLC_ACK 0x80
+#define SLC_FLUSHIN 0x40
+#define SLC_FLUSHOUT 0x20
+
+#define OLD_ENV_VAR 1
+#define OLD_ENV_VALUE 0
+#define NEW_ENV_VAR 0
+#define NEW_ENV_VALUE 1
+#define ENV_ESC 2
+#define ENV_USERVAR 3
+
+/*
+ * AUTHENTICATION suboptions
+ */
+
+/*
+ * Who is authenticating who ...
+ */
+#define AUTH_WHO_CLIENT 0 /* Client authenticating server */
+#define AUTH_WHO_SERVER 1 /* Server authenticating client */
+#define AUTH_WHO_MASK 1
+
+#define AUTHTYPE_NULL 0
+#define AUTHTYPE_KERBEROS_V4 1
+#define AUTHTYPE_KERBEROS_V5 2
+#define AUTHTYPE_SPX 3
+#define AUTHTYPE_MINK 4
+#define AUTHTYPE_CNT 5
+
+#define AUTHTYPE_TEST 99
+
+#ifdef AUTH_NAMES
+const char *authtype_names[] = {
+ "NULL", "KERBEROS_V4", "KERBEROS_V5", "SPX", "MINK", 0,
+};
+#else
+extern char *authtype_names[];
+#endif
+
+#define AUTHTYPE_NAME_OK(x) ((unsigned int)(x) < AUTHTYPE_CNT)
+#define AUTHTYPE_NAME(x) authtype_names[x]
+
+/*
+ * ENCRYPTion suboptions
+ */
+#define ENCRYPT_IS 0 /* I pick encryption type ... */
+#define ENCRYPT_SUPPORT 1 /* I support encryption types ... */
+#define ENCRYPT_REPLY 2 /* Initial setup response */
+#define ENCRYPT_START 3 /* Am starting to send encrypted */
+#define ENCRYPT_END 4 /* Am ending encrypted */
+#define ENCRYPT_REQSTART 5 /* Request you start encrypting */
+#define ENCRYPT_REQEND 6 /* Request you send encrypting */
+#define ENCRYPT_ENC_KEYID 7
+#define ENCRYPT_DEC_KEYID 8
+#define ENCRYPT_CNT 9
+
+#define ENCTYPE_ANY 0
+#define ENCTYPE_DES_CFB64 1
+#define ENCTYPE_DES_OFB64 2
+#define ENCTYPE_CNT 3
+
+#ifdef ENCRYPT_NAMES
+const char *encrypt_names[] = {
+ "IS", "SUPPORT", "REPLY", "START", "END",
+ "REQUEST-START", "REQUEST-END", "ENC-KEYID", "DEC-KEYID",
+ 0,
+};
+const char *enctype_names[] = {
+ "ANY", "DES_CFB64", "DES_OFB64", 0,
+};
+#else
+extern char *encrypt_names[];
+extern char *enctype_names[];
+#endif
+
+#define ENCRYPT_NAME_OK(x) ((unsigned int)(x) < ENCRYPT_CNT)
+#define ENCRYPT_NAME(x) encrypt_names[x]
+
+#define ENCTYPE_NAME_OK(x) ((unsigned int)(x) < ENCTYPE_CNT)
+#define ENCTYPE_NAME(x) enctype_names[x]
+
+/* normal */
+static const char *cmds[] = {
+ "IS", "SEND", "INFO",
+};
+
+/* 37: Authentication */
+static const char *authcmd[] = {
+ "IS", "SEND", "REPLY", "NAME",
+};
+static const char *authtype[] = {
+ "NULL", "KERBEROS_V4", "KERBEROS_V5", "SPX", "MINK",
+ "SRP", "RSA", "SSL", NULL, NULL,
+ "LOKI", "SSA", "KEA_SJ", "KEA_SJ_INTEG", "DSS",
+ "NTLM",
+};
+
+/* 38: Encryption */
+static const char *enccmd[] = {
+ "IS", "SUPPORT", "REPLY", "START", "END",
+ "REQUEST-START", "REQUEST-END", "END_KEYID", "DEC_KEYID",
+};
+static const char *enctype[] = {
+ "NULL", "DES_CFB64", "DES_OFB64", "DES3_CFB64", "DES3_OFB64",
+ NULL, "CAST5_40_CFB64", "CAST5_40_OFB64", "CAST128_CFB64", "CAST128_OFB64",
+};
+
+#define STR_OR_ID(x, tab) \
+ (((x) < sizeof(tab)/sizeof(tab[0]) && tab[(x)]) ? tab[(x)] : numstr(x))
+
+static char *
+numstr(int x)
+{
+ static char buf[20];
+
+ snprintf(buf, sizeof(buf), "%#x", x);
+ return buf;
+}
+
+/* sp points to IAC byte */
+static int
+telnet_parse(netdissect_options *ndo, const u_char *sp, u_int length, int print)