in readconf.c [134:179]
static int read_config_file_depth(const char *filename, struct passwd *pw,
const char *host, const char *original_host, Options *options,
int flags, int *activep, int *want_final_pass, int depth);
static int process_config_line_depth(Options *options, struct passwd *pw,
const char *host, const char *original_host, char *line,
const char *filename, int linenum, int *activep, int flags,
int *want_final_pass, int depth);
/* Keyword tokens. */
typedef enum {
oBadOption,
oHost, oMatch, oInclude,
oForwardAgent, oForwardX11, oForwardX11Trusted, oForwardX11Timeout,
oGatewayPorts, oExitOnForwardFailure,
oPasswordAuthentication, oRSAAuthentication,
oChallengeResponseAuthentication, oXAuthLocation,
oIdentityFile, oHostname, oPort, oCipher, oRemoteForward, oLocalForward,
oCertificateFile, oAddKeysToAgent, oIdentityAgent,
oUser, oEscapeChar, oRhostsRSAAuthentication, oProxyCommand,
oGlobalKnownHostsFile, oUserKnownHostsFile, oConnectionAttempts,
oBatchMode, oCheckHostIP, oStrictHostKeyChecking, oCompression,
oCompressionLevel, oTCPKeepAlive, oNumberOfPasswordPrompts,
oUsePrivilegedPort, oLogFacility, oLogLevel, oCiphers, oMacs,
oPubkeyAuthentication,
oKbdInteractiveAuthentication, oKbdInteractiveDevices, oHostKeyAlias,
oDynamicForward, oPreferredAuthentications, oHostbasedAuthentication,
oHostKeyAlgorithms, oBindAddress, oBindInterface, oPKCS11Provider,
oClearAllForwardings, oNoHostAuthenticationForLocalhost,
oEnableSSHKeysign, oRekeyLimit, oVerifyHostKeyDNS, oConnectTimeout,
oAddressFamily, oGssAuthentication, oGssDelegateCreds,
oGssServerIdentity,
oServerAliveInterval, oServerAliveCountMax, oIdentitiesOnly,
oSendEnv, oSetEnv, oControlPath, oControlMaster, oControlPersist,
oHashKnownHosts,
oTunnel, oTunnelDevice,
oLocalCommand, oPermitLocalCommand, oRemoteCommand,
oVisualHostKey,
oKexAlgorithms, oIPQoS, oRequestTTY, oIgnoreUnknown, oProxyUseFdpass,
oCanonicalDomains, oCanonicalizeHostname, oCanonicalizeMaxDots,
oCanonicalizeFallbackLocal, oCanonicalizePermittedCNAMEs,
oStreamLocalBindMask, oStreamLocalBindUnlink, oRevokedHostKeys,
oFingerprintHash, oUpdateHostkeys, oHostbasedKeyTypes,
oPubkeyAcceptedKeyTypes, oCASignatureAlgorithms, oProxyJump,
oIgnore, oIgnoredUnknownOption, oDeprecated, oUnsupported
} OpCodes;