## nm-utils nm-utils — Utility functions |

## Synopsis

    #include <nm-utils.h>

    gboolean            nm_utils_init                       (GError **error);
    void                nm_utils_deinit                     (void);
    gboolean            nm_utils_is_empty_ssid              (const guint8 *ssid,
                                                             int len);
    const char *        nm_utils_escape_ssid                (const guint8 *ssid,
                                                             guint32 len);
    gboolean            nm_utils_same_ssid                  (const GByteArray *ssid1,
                                                             const GByteArray *ssid2,
                                                             gboolean ignore_trailing_null);
    char *              nm_utils_ssid_to_utf8               (const GByteArray *ssid);
    GHashTable *        nm_utils_gvalue_hash_dup            (GHashTable *hash);
    void                nm_utils_slist_free                 (GSList *list,
                                                             GDestroyNotify elem_destroy_fn);
    enum                NMUtilsSecurityType;
    gboolean            nm_utils_security_valid             (NMUtilsSecurityType type,
                                                             guint32 wifi_caps,
                                                             gboolean have_ap,
                                                             gboolean adhoc,
                                                             guint32 ap_flags,
                                                             guint32 ap_wpa,
                                                             guint32 ap_rsn);
    GSList *            nm_utils_ip4_addresses_from_gvalue  (const GValue *value);
    void                nm_utils_ip4_addresses_to_gvalue    (GSList *list,
                                                             GValue *value);
    GSList *            nm_utils_ip4_routes_from_gvalue     (const GValue *value);
    void                nm_utils_ip4_routes_to_gvalue       (GSList *list,
                                                             GValue *value);
    guint32             nm_utils_ip4_netmask_to_prefix      (guint32 netmask);
    guint32             nm_utils_ip4_prefix_to_netmask      (guint32 prefix);
    guint32             nm_utils_ip4_get_default_prefix     (guint32 ip);
    GSList *            nm_utils_ip6_addresses_from_gvalue  (const GValue *value);
    void                nm_utils_ip6_addresses_to_gvalue    (GSList *list,
                                                             GValue *value);
    GSList *            nm_utils_ip6_routes_from_gvalue     (const GValue *value);
    void                nm_utils_ip6_routes_to_gvalue       (GSList *list,
                                                             GValue *value);
    GSList *            nm_utils_ip6_dns_from_gvalue        (const GValue *value);
    void                nm_utils_ip6_dns_to_gvalue          (GSList *list,
                                                             GValue *value);
    char *              nm_utils_uuid_generate              (void);
    char *              nm_utils_uuid_generate_from_string  (const char *s);
    GByteArray *        nm_utils_rsa_key_encrypt            (const GByteArray *data,
                                                             const char *in_password,
                                                             char **out_password,
                                                             GError **error);
    guint32             nm_utils_wifi_freq_to_channel       (guint32 freq);
    guint32             nm_utils_wifi_channel_to_freq       (guint32 channel,
                                                             const char *band);
    guint32             nm_utils_wifi_find_next_channel     (guint32 channel,
                                                             int direction,
                                                             char *band);
    gboolean            nm_utils_wifi_is_channel_valid      (guint32 channel,
                                                             const char *band);

## Description

A collection of utility functions for working SSIDs, IP addresses, WiFi access points and devices, among other things.

## Details

### nm_utils_init ()

    gboolean            nm_utils_init                       (GError **error);

Initializes libnm-util; should be called when starting and program that uses libnm-util. Sets up an `atexit()` handler to ensure de-initialization is performed, but calling `nm_utils_deinit()` to explicitly deinitialize libnm-util can also be done. This function can be called more than once.

`error` : | location to store error, or `NULL`
Returns : | TRUE if the initialization was successful, FALSE on failure.

### nm_utils_deinit ()

    void                nm_utils_deinit                     (void);

Frees all resources used internally by libnm-util. This function is called from an `atexit()` handler, set up by `nm_utils_init()`, but is safe to be called more than once. Subsequent calls have no effect until `nm_utils_init()` is called again.

### nm_utils_is_empty_ssid ()

    gboolean            nm_utils_is_empty_ssid              (const guint8 *ssid,
                                                             int len);

Different manufacturers use different mechanisms for not broadcasting the AP's SSID. This function attempts to detect blank/empty SSIDs using a number of known SSID-cloaking methods.

`ssid` : | pointer to a buffer containing the SSID data
`len` : | length of the SSID data in `ssid`
Returns : | TRUE if the SSID is "empty", FALSE if it is not

### nm_utils_escape_ssid ()

    const char *        nm_utils_escape_ssid                (const guint8 *ssid,
                                                             guint32 len);

This function does a quick printable character conversion of the SSID, simply replacing embedded NULLs and non-printable characters with the hexadecimal representation of that character. Intended for debugging only, should not be used for display of SSIDs.

`ssid` : | pointer to a buffer containing the SSID data
`len` : | length of the SSID data in `ssid`
Returns : | pointer to the escaped SSID, which uses an internal static buffer and will be overwritten by subsequent calls to this function

### nm_utils_same_ssid ()

    gboolean            nm_utils_same_ssid                  (const GByteArray *ssid1,
                                                             const GByteArray *ssid2,
                                                             gboolean ignore_trailing_null);

Earlier versions of the Linux kernel added a NULL byte to the end of the SSID to enable easy printing of the SSID on the console or in a terminal, but this behavior was problematic (SSIDs are simply byte arrays, not strings) and thus was changed. This function compensates for that behavior at the cost of some compatibility with odd SSIDs that may legitimately have trailing NULLs, even though that is functionally pointless.

`ssid1` : | first SSID data to compare
`ssid2` : | second SSID data to compare
`ignore_trailing_null` : | TRUE to ignore one trailing NULL byte
Returns : | TRUE if the SSIDs are the same, FALSE if they are not

### nm_utils_ssid_to_utf8 ()

    char *              nm_utils_ssid_to_utf8               (const GByteArray *ssid);

WiFi SSIDs are byte arrays, they are _not_ strings. Thus, an SSID may contain embedded NULLs and other unprintable characters. Often it is useful to print the SSID out for debugging purposes, but that should be the _only_ use of this function. Do not use this function for any persistent storage of the SSID, since the printable SSID returned from this function cannot be converted back into the real SSID of the access point.

This function does almost everything humanly possible to convert the input into a printable UTF-8 string, using roughly the following procedure:

1) if the input data is already UTF-8 safe, no conversion is performed 2) attempts to get the current system language from the LANG environment variable, and depending on the language, uses a table of alternative encodings to try. For example, if LANG=hu_HU, the table may first try the ISO-8859-2 encoding, and if that fails, try the Windows-1250 encoding. If all fallback encodings fail, replaces non-UTF-8 characters with '?'. 3) If the system language was unable to be determined, falls back to the ISO-8859-1 encoding, then to the Windows-1251 encoding. 4) If step 3 fails, replaces non-UTF-8 characters with '?'.

Again, this function should be used for debugging and display purposes _only_.

`ssid` : | a byte array containing the SSID data
Returns : | an allocated string containing a UTF-8 representation of the SSID, which must be freed by the caller using `g_free()`. Returns NULL on errors. [transfer full]

### nm_utils_gvalue_hash_dup ()

    GHashTable *        nm_utils_gvalue_hash_dup            (GHashTable *hash);

Utility function to duplicate a hash table of GValues.

`hash` : | a GHashTable mapping string:GValue
Returns : | a newly allocated duplicated GHashTable, caller must free the returned hash with `g_hash_table_unref()` or `g_hash_table_destroy()`. [transfer container][element-type utf8 GObject.Value]

### nm_utils_slist_free ()

    void                nm_utils_slist_free                 (GSList *list,
                                                             GDestroyNotify elem_destroy_fn);

Utility function to free a GSList.

`list` : | a GSList
`elem_destroy_fn` : | user function called for each element in `list`

### enum NMUtilsSecurityType

    typedef enum {
    	NMU_SEC_INVALID = 0,
    	NMU_SEC_NONE,
    	NMU_SEC_STATIC_WEP,
    	NMU_SEC_LEAP,
    	NMU_SEC_DYNAMIC_WEP,
    	NMU_SEC_WPA_PSK,
    	NMU_SEC_WPA_ENTERPRISE,
    	NMU_SEC_WPA2_PSK,
    	NMU_SEC_WPA2_ENTERPRISE
    } NMUtilsSecurityType;

### nm_utils_security_valid ()

    gboolean            nm_utils_security_valid             (NMUtilsSecurityType type,
                                                             guint32 wifi_caps,
                                                             gboolean have_ap,
                                                             gboolean adhoc,
                                                             guint32 ap_flags,
                                                             guint32 ap_wpa,
                                                             guint32 ap_rsn);

Given a set of device capabilities, and a desired security type to check against, determines whether the combination of device, desired security type, and AP capabilities intersect.

`type` : | the security type to check AP flags and device capabilties against, e.g. NMU_SEC_STATIC_WEP
`wifi_caps` : | bitfield of the capabilities of the specific WiFi device, e.g. NM_WIFI_DEVICE_CAP_CIPHER_WEP40
`have_ap` : | whether the `ap_flags`, `ap_wpa`, and `ap_rsn` arguments are valid
`adhoc` : | whether the capabilities being tested are from an Ad-Hoc AP (IBSS)
`ap_flags` : | bitfield of AP capabilities, e.g. NM_802_11_AP_FLAGS_PRIVACY
`ap_wpa` : | bitfield of AP capabilties derived from the AP's WPA beacon, e.g. (NM_802_11_AP_SEC_PAIR_TKIP | NM_802_11_AP_SEC_KEY_MGMT_PSK)
`ap_rsn` : | bitfield of AP capabilties derived from the AP's RSN/WPA2 beacon, e.g. (NM_802_11_AP_SEC_PAIR_CCMP | NM_802_11_AP_SEC_PAIR_TKIP)
Returns : | TRUE if the device capabilities and AP capabilties intersect and are compatible with the desired `type`, FALSE if they are not

### nm_utils_ip4_addresses_from_gvalue ()

    GSList *            nm_utils_ip4_addresses_from_gvalue  (const GValue *value);

Utility function to convert a GPtrArray of GArrays of guint32s representing a list of NetworkManager IPv4 addresses (which is a tuple of address, gateway, and prefix) into a GSList of NMIP4Address objects. The specific format of this serialization is not guaranteed to be stable and the GArray may be extended in the future.

`value` : | gvalue containing a GPtrArray of GArrays of guint32s
Returns : | a newly allocated GSList of NMIP4Address objects. [transfer full][element-type NetworkManager.IP4Address]

### nm_utils_ip4_addresses_to_gvalue ()

    void                nm_utils_ip4_addresses_to_gvalue    (GSList *list,
                                                             GValue *value);

Utility function to convert a GSList of NMIP4Address objects into a GPtrArray of GArrays of guint32s representing a list of NetworkManager IPv4 addresses (which is a tuple of address, gateway, and prefix). The specific format of this serialization is not guaranteed to be stable and may be extended in the future.

`list` : | a list of NMIP4Address objects
`value` : | a pointer to a GValue into which to place the converted addresses, which should be unset by the caller (when no longer needed) with `g_value_unset()`.

### nm_utils_ip4_routes_from_gvalue ()

    GSList *            nm_utils_ip4_routes_from_gvalue     (const GValue *value);

Utility function to convert a GPtrArray of GArrays of guint32s representing a list of NetworkManager IPv4 routes (which is a tuple of route, next hop, prefix, and metric) into a GSList of NMIP4Route objects. The specific format of this serialization is not guaranteed to be stable and may be extended in the future.

`value` : | gvalue containing a GPtrArray of GArrays of guint32s
Returns : | a newly allocated GSList of NMIP4Route objects. [transfer full][element-type NetworkManager.IP4Route]

### nm_utils_ip4_routes_to_gvalue ()

    void                nm_utils_ip4_routes_to_gvalue       (GSList *list,
                                                             GValue *value);

Utility function to convert a GSList of NMIP4Route objects into a GPtrArray of GArrays of guint32s representing a list of NetworkManager IPv4 routes (which is a tuple of route, next hop, prefix, and metric). The specific format of this serialization is not guaranteed to be stable and may be extended in the future.

`list` : | a list of NMIP4Route objects
`value` : | a pointer to a GValue into which to place the converted routes, which should be unset by the caller (when no longer needed) with `g_value_unset()`.

### nm_utils_ip4_netmask_to_prefix ()

    guint32             nm_utils_ip4_netmask_to_prefix      (guint32 netmask);

`netmask` : | an IPv4 netmask in network byte order
Returns : | the CIDR prefix represented by the netmask

### nm_utils_ip4_prefix_to_netmask ()

    guint32             nm_utils_ip4_prefix_to_netmask      (guint32 prefix);

`prefix` : | a CIDR prefix
Returns : | the netmask represented by the prefix

### nm_utils_ip4_get_default_prefix ()

    guint32             nm_utils_ip4_get_default_prefix     (guint32 ip);

When the Internet was originally set up, various ranges of IP addresses were segmented into three network classes: A, B, and C. This function will return a prefix that is associated with the IP address specified defining where it falls in the predefined classes.

`ip` : | an IPv4 address (in network byte order)
Returns : | the default class prefix for the given IP

### nm_utils_ip6_addresses_from_gvalue ()

    GSList *            nm_utils_ip6_addresses_from_gvalue  (const GValue *value);

Utility function to convert a GPtrArray of GValueArrays of (GArray of guchars) and guint32 representing a list of NetworkManager IPv6 addresses (which is a tuple of address, prefix, and gateway), into a GSList of NMIP6Address objects. The specific format of this serialization is not guaranteed to be stable and the GValueArray may be extended in the future.

`value` : | gvalue containing a GPtrArray of GValueArrays of (GArray of guchars) and guint32
Returns : | a newly allocated GSList of NMIP6Address objects. [transfer full][element-type NetworkManager.IP6Address]

### nm_utils_ip6_addresses_to_gvalue ()

    void                nm_utils_ip6_addresses_to_gvalue    (GSList *list,
                                                             GValue *value);

Utility function to convert a GSList of NMIP6Address objects into a GPtrArray of GValueArrays representing a list of NetworkManager IPv6 addresses (which is a tuple of address, prefix, and gateway). The specific format of this serialization is not guaranteed to be stable and may be extended in the future.

`list` : | a list of NMIP6Address objects
`value` : | a pointer to a GValue into which to place the converted addresses, which should be unset by the caller (when no longer needed) with `g_value_unset()`.

### nm_utils_ip6_routes_from_gvalue ()

    GSList *            nm_utils_ip6_routes_from_gvalue     (const GValue *value);

Utility function GPtrArray of GValueArrays of (GArray or guchars), guint32, (GArray of guchars), and guint32 representing a list of NetworkManager IPv6 routes (which is a tuple of destination, prefix, next hop, and metric) into a GSList of NMIP6Route objects. The specific format of this serialization is not guaranteed to be stable and may be extended in the future.

`value` : | gvalue containing a GPtrArray of GValueArrays of (GArray or guchars), guint32, (GArray of guchars), and guint32
Returns : | a newly allocated GSList of NMIP6Route objects. [transfer full][element-type NetworkManager.IP6Route]

### nm_utils_ip6_routes_to_gvalue ()

    void                nm_utils_ip6_routes_to_gvalue       (GSList *list,
                                                             GValue *value);

Utility function to convert a GSList of NMIP6Route objects into a GPtrArray of GValueArrays of (GArray or guchars), guint32, (GArray of guchars), and guint32 representing a list of NetworkManager IPv6 routes (which is a tuple of destination, prefix, next hop, and metric). The specific format of this serialization is not guaranteed to be stable and may be extended in the future.

`list` : | a list of NMIP6Route objects
`value` : | a pointer to a GValue into which to place the converted routes, which should be unset by the caller (when no longer needed) with `g_value_unset()`.

### nm_utils_ip6_dns_from_gvalue ()

    GSList *            nm_utils_ip6_dns_from_gvalue        (const GValue *value);

### nm_utils_ip6_dns_to_gvalue ()

    void                nm_utils_ip6_dns_to_gvalue          (GSList *list,
                                                             GValue *value);

### nm_utils_uuid_generate ()

    char *              nm_utils_uuid_generate              (void);

Returns : | a newly allocated UUID suitable for use as the NMSettingConnection object's "id": property. Should be freed with `g_free()`

### nm_utils_uuid_generate_from_string ()

    char *              nm_utils_uuid_generate_from_string  (const char *s);

For a given `s`, this function will always return the same UUID.

`s` : | a string to use as the seed for the UUID
Returns : | a newly allocated UUID suitable for use as the NMSettingConnection object's "id": property

### nm_utils_rsa_key_encrypt ()

    GByteArray *        nm_utils_rsa_key_encrypt            (const GByteArray *data,
                                                             const char *in_password,
                                                             char **out_password,
                                                             GError **error);

Encrypts the given RSA private key data with the given password (or generates a password if no password was given) and converts the data to PEM format suitable for writing to a file.

`data` : | RSA private key data to be encrypted
`in_password` : | existing password to use, if any. [allow-none]
`out_password` : | if `in_password` was NULL, a random password will be generated and returned in this argument. [out][allow-none]
`error` : | detailed error information on return, if an error occurred
Returns : | on success, PEM-formatted data suitable for writing to a PEM-formatted certificate/private key file. [transfer full]

### nm_utils_wifi_freq_to_channel ()

    guint32             nm_utils_wifi_freq_to_channel       (guint32 freq);

Utility function to translate a WiFi frequency to its corresponding channel.

`freq` : | frequency
Returns : | the channel represented by the frequency or 0

### nm_utils_wifi_channel_to_freq ()

    guint32             nm_utils_wifi_channel_to_freq       (guint32 channel,
                                                             const char *band);

Utility function to translate a WiFi channel to its corresponding frequency.

`channel` : | channel
`band` : | frequency band for wireless ("a" or "bg")
Returns : | the frequency represented by the channel of the band, or -1 when the freq is invalid, or 0 when the band is invalid

### nm_utils_wifi_find_next_channel ()

    guint32             nm_utils_wifi_find_next_channel     (guint32 channel,
                                                             int direction,
                                                             char *band);

Utility function to find out next/previous WiFi channel for a channel.

`channel` : | current channel
`direction` : | whether going downward (0 or less) or upward (1 or more)
`band` : | frequency band for wireless ("a" or "bg")
Returns : | the next channel in the specified direction or 0

### nm_utils_wifi_is_channel_valid ()

    gboolean            nm_utils_wifi_is_channel_valid      (guint32 channel,
                                                             const char *band);

Utility function to verify WiFi channel validity.

`channel` : | channel
`band` : | frequency band for wireless ("a" or "bg")
Returns : | TRUE or FALSE