config.c

关于tor匿名通信的源代码

  V(BWHistoryReadValues,              CSV,      ""),
  V(BWHistoryWriteEnds,               ISOTIME,  NULL),
  V(BWHistoryWriteInterval,           UINT,     "900"),
  V(BWHistoryWriteValues,             CSV,      ""),

  V(TorVersion,                       STRING,   NULL),

  V(LastRotatedOnionKey,              ISOTIME,  NULL),
  V(LastWritten,                      ISOTIME,  NULL),

  { NULL, CONFIG_TYPE_OBSOLETE, 0, NULL }
};

#undef VAR
#undef V
#undef OBSOLETE

/** Represents an English description of a configuration variable; used when
 * generating configuration file comments. */
typedef struct config_var_description_t {
  const char *name;
  const char *description;
} config_var_description_t;

static config_var_description_t options_description[] = {
  /* ==== general options */
  { "AvoidDiskWrites", "If non-zero, try to write to disk less frequently than"
    " we would otherwise." },
  { "BandwidthRate", "A token bucket limits the average incoming bandwidth on "
    "this node to the specified number of bytes per second." },
  { "BandwidthBurst", "Limit the maximum token buffer size (also known as "
    "burst) to the given number of bytes." },
  { "ConnLimit", "Minimum number of simultaneous sockets we must have." },
  { "ConstrainedSockets", "Shrink tx and rx buffers for sockets to avoid "
    "system limits on vservers and related environments.  See man page for "
    "more information regarding this option." },
  { "ConstrainedSockSize", "Limit socket buffers to this size when "
    "ConstrainedSockets is enabled." },
  /*  ControlListenAddress */
  { "ControlPort", "If set, Tor will accept connections from the same machine "
    "(localhost only) on this port, and allow those connections to control "
    "the Tor process using the Tor Control Protocol (described in"
    "control-spec.txt).", },
  { "CookieAuthentication", "If this option is set to 1, don't allow any "
    "connections to the control port except when the connecting process "
    "can read a file that Tor creates in its data directory." },
  { "DataDirectory", "Store working data, state, keys, and caches here." },
  { "DirServer", "Tor only trusts directories signed with one of these "
    "servers' keys.  Used to override the standard list of directory "
    "authorities." },
  /* { "FastFirstHopPK", "" }, */
  /* FetchServerDescriptors, FetchHidServDescriptors,
   * FetchUselessDescriptors */
  { "Group", "On startup, setgid to this group." },
  { "HardwareAccel", "If set, Tor tries to use hardware crypto accelerators "
    "when it can." },
  /* HashedControlPassword */
  { "HTTPProxy", "Force Tor to make all HTTP directory requests through this "
    "host:port (or host:80 if port is not set)." },
  { "HTTPProxyAuthenticator", "A username:password pair to be used with "
    "HTTPProxy." },
  { "HTTPSProxy", "Force Tor to make all TLS (SSL) connectinos through this "
    "host:port (or host:80 if port is not set)." },
  { "HTTPSProxyAuthenticator", "A username:password pair to be used with "
    "HTTPSProxy." },
  { "KeepalivePeriod", "Send a padding cell every N seconds to keep firewalls "
    "from closing our connections while Tor is not in use." },
  { "Log", "Where to send logging messages.  Format is "
    "minSeverity[-maxSeverity] (stderr|stdout|syslog|file FILENAME)." },
  { "OutboundBindAddress", "Make all outbound connections originate from the "
    "provided IP address (only useful for multiple network interfaces)." },
  { "PIDFile", "On startup, write our PID to this file. On clean shutdown, "
    "remove the file." },
  { "PreferTunneledDirConns", "If non-zero, avoid directory servers that "
    "don't support tunneled connections." },
  /* PreferTunneledDirConns */
  /* ProtocolWarnings */
  /* RephistTrackTime */
  { "RunAsDaemon", "If set, Tor forks and daemonizes to the background when "
    "started.  Unix only." },
  { "SafeLogging", "If set to 0, Tor logs potentially sensitive strings "
    "rather than replacing them with the string [scrubbed]." },
  { "TunnelDirConns", "If non-zero, when a directory server we contact "
    "supports it, we will build a one-hop circuit and make an encrypted "
    "connection via its ORPort." },
  { "User", "On startup, setuid to this user" },

  /* ==== client options */
  { "AllowInvalidNodes", "Where on our circuits should Tor allow servers "
    "that the directory authorities haven't called \"valid\"?" },
  { "AllowNonRFC953Hostnames", "If set to 1, we don't automatically reject "
    "hostnames for having invalid characters." },
  /*  CircuitBuildTimeout, CircuitIdleTimeout */
  { "ClientOnly", "If set to 1, Tor will under no circumstances run as a "
    "server, even if ORPort is enabled." },
  { "EntryNodes", "A list of preferred entry nodes to use for the first hop "
    "in circuits, when possible." },
  /* { "EnforceDistinctSubnets" , "" }, */
  { "ExitNodes", "A list of preferred nodes to use for the last hop in "
    "circuits, when possible." },
  { "ExcludeNodes", "A list of nodes never to use when building a circuit." },
  { "FascistFirewall", "If set, Tor will only create outgoing connections to "
    "servers running on the ports listed in FirewallPorts." },
  { "FirewallPorts", "A list of ports that we can connect to.  Only used "
    "when FascistFirewall is set." },
  { "LongLivedPorts", "A list of ports for services that tend to require "
    "high-uptime connections." },
  { "MapAddress", "Force Tor to treat all requests for one address as if "
    "they were for another." },
  { "NewCircuitPeriod", "Force Tor to consider whether to build a new circuit "
    "every NUM seconds." },
  { "MaxCircuitDirtiness", "Do not attach new streams to a circuit that has "
    "been used more than this many seconds ago." },
  /* NatdPort, NatdListenAddress */
  { "NodeFamily", "A list of servers that constitute a 'family' and should "
    "never be used in the same circuit." },
  { "NumEntryGuards", "How many entry guards should we keep at a time?" },
  /* PathlenCoinWeight */
  { "ReachableAddresses", "Addresses we can connect to, as IP/bits:port-port. "
    "By default, we assume all addresses are reachable." },
  /* reachablediraddresses, reachableoraddresses. */
  { "RendNodes", "A list of preferred nodes to use for a rendezvous point, "
    "when possible." },
  { "RendExcludenodes", "A list of nodes never to use as rendezvous points." },
  /* SafeSOCKS */
  { "SOCKSPort", "The port where we listen for SOCKS connections from "
    "applications." },
  { "SOCKSListenAddress", "Bind to this address to listen to connections from "
    "SOCKS-speaking applications." },
  { "SOCKSPolicy", "Set an entry policy to limit which addresses can connect "
    "to the SOCKSPort." },
  /* SocksTimeout */
  { "StrictExitNodes", "If set, Tor will fail to operate when none of the "
    "configured ExitNodes can be used." },
  { "StrictEntryNodes", "If set, Tor will fail to operate when none of the "
    "configured EntryNodes can be used." },
  /* TestSocks */
  { "TrackHostsExit", "Hosts and domains which should, if possible, be "
    "accessed from the same exit node each time we connect to them." },
  { "TrackHostsExitExpire", "Time after which we forget which exit we were "
    "using to connect to hosts in TrackHostsExit." },
  /* "TransPort", "TransListenAddress */
  { "UseEntryGuards", "Set to 0 if we want to pick from the whole set of "
    "servers for the first position in each circuit, rather than picking a "
    "set of 'Guards' to prevent profiling attacks." },

  /* === server options */
  { "Address", "The advertised (external) address we should use." },
  /* Accounting* options. */
  /* AssumeReachable */
  { "ContactInfo", "Administrative contact information to advertise for this "
    "server." },
  { "ExitPolicy", "Address/port ranges for which to accept or reject outgoing "
    "connections on behalf of Tor users." },
  /*  { "ExitPolicyRejectPrivate, "" }, */
  { "MaxAdvertisedBandwidth", "If set, we will not advertise more than this "
    "amount of bandwidth for our bandwidth rate, regardless of how much "
    "bandwidth we actually detect." },
  { "MaxOnionsPending", "Reject new attempts to extend circuits when we "
    "already have this many pending." },
  { "MyFamily", "Declare a list of other servers as belonging to the same "
    "family as this one, so that clients will not use two from the same "
    "family in the same circuit." },
  { "Nickname", "Set the server nickname." },
  { "NoPublish", "{DEPRECATED}" },
  { "NumCPUs", "How many processes to use at once for public-key crypto." },
  { "ORPort", "Advertise this port to listen for connections from Tor clients "
    "and servers." },
  { "ORListenAddress", "Bind to this address to listen for connections from "
    "clients and servers, instead of the default 0.0.0.0:ORPort." },
  { "PublishServerDescriptor", "Set to 0 to keep the server from "
    "uploading info to the directory authorities." },
  /*{ "RedirectExit", "When an outgoing connection tries to connect to a "
   *"given address, redirect it to another address instead." },
   */
  /* ServerDNS: DetectHijacking, ResolvConfFile, SearchDomains */
  { "ShutdownWaitLength", "Wait this long for clients to finish when "
    "shutting down because of a SIGINT." },
  /* { "TestVia", } */

  /* === directory cache options */
  { "DirPort", "Serve directory information from this port, and act as a "
    "directory cache." },
  { "DirListenAddress", "Bind to this address to listen for connections from "
    "clients and servers, instead of the default 0.0.0.0:DirPort." },
  { "DirPolicy", "Set a policy to limit who can connect to the directory "
    "port" },

  /*  Authority options: AuthDirBadExit, AuthDirInvalid, AuthDirReject,
   * AuthDirRejectUnlisted, AuthDirListBadExits, AuthoritativeDirectory,
   * DirAllowPrivateAddresses, HSAuthoritativeDir,
   * NamingAuthoritativeDirectory, RecommendedVersions,
   * RecommendedClientVersions, RecommendedServerVersions, RendPostPeriod,
   * RunTesting, V1AuthoritativeDirectory, VersioningAuthoritativeDirectory, */

  /* Hidden service options: HiddenService: dir,excludenodes, nodes,
   * options, port.  PublishHidServDescriptor */

  /* Nonpersistent options: __LeaveStreamsUnattached, __AllDirActionsPrivate */
  { NULL, NULL },
};

static config_var_description_t state_description[] = {
  { "AccountingBytesReadInInterval",
    "How many bytes have we read in this accounting period?" },
  { "AccountingBytesWrittenInInterval",
    "How many bytes have we written in this accounting period?" },
  { "AccountingExpectedUsage",
    "How many bytes did we expect to use per minute? (0 for no estimate.)" },
  { "AccountingIntervalStart", "When did this accounting period begin?" },
  { "AccountingSecondsActive", "How long have we been awake in this period?" },

  { "BWHistoryReadEnds", "When does the last-recorded read-interval end?" },
  { "BWHistoryReadInterval", "How long is each read-interval (in seconds)?" },
  { "BWHistoryReadValues", "Number of bytes read in each interval." },
  { "BWHistoryWriteEnds", "When does the last-recorded write-interval end?" },
  { "BWHistoryWriteInterval", "How long is each write-interval (in seconds)?"},
  { "BWHistoryWriteValues", "Number of bytes written in each interval." },

  { "EntryGuard", "One of the nodes we have chosen as a fixed entry" },
  { "EntryGuardDownSince",
    "The last entry guard has been unreachable since this time." },
  { "EntryGuardUnlistedSince",
    "The last entry guard has been unusable since this time." },

  { "LastRotatedOnionKey",
    "The last time at which we changed the medium-term private key used for "
    "building circuits." },
  { "LastWritten", "When was this state file last regenerated?" },

  { "TorVersion", "Which version of Tor generated this state file?" },
  { NULL, NULL },
};

/** Type of a callback to validate whether a given configuration is
 * well-formed and consistent. See options_trial_assign() for documentation
 * of arguments. */
typedef int (*validate_fn_t)(void*,void*,int,char**);

/** Information on the keys, value types, key-to-struct-member mappings,
 * variable descriptions, validation functions, and abbreviations for a
 * configuration or storage format. */
typedef struct {
  size_t size; /**< Size of the struct that everything gets parsed into. */
  uint32_t magic; /**< Required 'magic value' to make sure we have a struct
                   * of the right type. */
  off_t magic_offset; /**< Offset of the magic value within the struct. */
  config_abbrev_t *abbrevs; /**< List of abbreviations that we expand when
                             * parsing this format. */
  config_var_t *vars; /**< List of variables we recognize, their default
                       * values, and where we stick them in the structure. */
  validate_fn_t validate_fn; /**< Function to validate config. */
  /** Documentation for configuration variables. */
  config_var_description_t *descriptions;
  /** If present, extra is a LINELIST variable for unrecognized
   * lines.  Otherwise, unrecognized lines are an error. */
  config_var_t *extra;
} config_format_t;

/** Macro: assert that <b>cfg</b> has the right magic field for format
 * <b>fmt</b>. */
#define CHECK(fmt, cfg) STMT_BEGIN                                      \
    tor_assert(fmt && cfg);                                             \
    tor_assert((fmt)->magic ==                                          \
               *(uint32_t*)STRUCT_VAR_P(cfg,fmt->magic_offset));        \
  STMT_END

static void config_line_append(config_line_t **lst,
                               const char *key, const char *val);
static void option_clear(config_format_t *fmt, or_options_t *options,
                         config_var_t *var);
static void option_reset(config_format_t *fmt, or_options_t *options,
                         config_var_t *var, int use_defaults);
static void config_free(config_format_t *fmt, void *options);
static int config_lines_eq(config_line_t *a, config_line_t *b);
static int option_is_same(config_format_t *fmt,
                          or_options_t *o1, or_options_t *o2,
                          const char *name);
static or_options_t *options_dup(config_format_t *fmt, or_options_t *old);
static int options_validate(or_options_t *old_options, or_options_t *options,
                            int from_setconf, char **msg);
static int options_act_reversible(or_options_t *old_options, char **msg);
static int options_act(or_options_t *old_options);
static int options_transition_allowed(or_options_t *old, or_options_t *new,
                                      char **msg);
static int options_transition_affects_workers(or_options_t *old_options,
                                              or_options_t *new_options);
static int options_transition_affects_descriptor(or_options_t *old_options,
                                                 or_options_t *new_options);
static int check_nickname_list(const char *lst, const char *name, char **msg);
static void config_register_addressmaps(or_options_t *options);

static int parse_bridge_line(const char *line, int validate_only);
static int parse_dir_server_line(const char *line,
                                 authority_type_t required_type,
                                 int validate_only);
static int parse_redirect_line(smartlist_t *result,
                               config_line_t *line, char **msg);
static int validate_data_directory(or_options_t *options);
static int write_configuration_file(const char *fname, or_options_t *options);
static config_line_t *get_assigned_option(config_format_t *fmt,
                                      or_options_t *options, const char *key,
                                      int escape_val);
static void config_init(config_format_t *fmt, void *options);
static int or_state_validate(or_state_t *old_options, or_state_t *options,
                             int from_setconf, char **msg);
static int or_state_load(void);
static int options_init_logs(or_options_t *options, int validate_only);

static uint64_t config_parse_memunit(const char *s, int *ok);
static int config_parse_interval(const char *s, int *ok);
static void print_svn_version(void);
static void init_libevent(void);
static int opt_streq(const char *s1, const char *s2);
/** Versions of libevent. */
typedef enum {
  /* Note: we compare these, so it's important that "old" precede everything,
   * and that "other" come last. */
  LE_OLD=0, LE_10C, LE_10D, LE_10E, LE_11, LE_11A, LE_11B, LE_12, LE_12A,
  LE_13, LE_13A, LE_13B, LE_13C, LE_13D,
  LE_OTHER
} le_version_t;
static le_version_t decode_libevent_version(void);
#if defined(HAVE_EVENT_GET_VERSION) && defined(HAVE_EVENT_GET_METHOD)
static void check_libevent_version(const char *m, int server);
#endif

/** Magic value for or_options_t. */
#define OR_OPTIONS_MAGIC 9090909

/** Configuration format for or_options_t. */
static config_format_t options_format = {
  sizeof(or_options_t),
  OR_OPTIONS_MAGIC,