ip-utils.c File Reference

IP address related utility functions. More...

#include <errno.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <net/if.h>
#include <string.h>
#include <unistd.h>
#include <glib.h>
#include "ip-utils.h"

Include dependency graph for ip-utils.c:

Functions
const struct ifaddrs *	janus_network_query_devices (const struct ifaddrs *ifa, const janus_network_query_config *query)
	Look up network devices matching the given query. The first matching device is returned, so to find all matching devices simply pass the ifa_next of the returned device in a subsequent call to this function to find more matches. More...
int	janus_network_prepare_device_query (const char *user_value, const janus_network_query_options query_mode, janus_network_query_config *query)
	Initialise a network device query. More...
int	janus_network_prepare_device_query_default (const char *user_value, janus_network_query_config *query)
	Initialise a network device query with default query options. This function will Initialise the query to accept any supported match type. More...
int	janus_network_get_devices_ipv4 (const struct ifaddrs *ifa, const janus_network_query_config *query, struct in_addr *result)
	Copies the IPv4 address from a network inteface description to the given result structure. More...
int	janus_network_get_devices_ipv6 (const struct ifaddrs *ifa, const janus_network_query_config *query, struct in6_addr *result)
	Copies the IPv6 address from a network inteface description to the given result structure. More...
int	janus_network_get_device_address (const struct ifaddrs *ifa, janus_network_address *result)
	Copies the IP address from a network interface description to the given result structure. More...
void	janus_network_address_nullify (janus_network_address *a)
	Set the given network address to a null/nil value. More...
int	janus_network_address_is_null (const janus_network_address *a)
	Test if a given network address is null-valued. More...
int	janus_network_address_from_sockaddr (struct sockaddr *s, janus_network_address *a)
	Convert a struct sockaddr to a janus_network_address. More...
int	janus_network_address_to_string_buffer (const janus_network_address *a, janus_network_address_string_buffer *buf)
	Convert the given network address to a form which can be used to extract a human readable network address from. More...
void	janus_network_address_string_buffer_nullify (janus_network_address_string_buffer *b)
	Set the given network address string buffer to a null/nil value. More...
int	janus_network_address_string_buffer_is_null (const janus_network_address_string_buffer *b)
	Test if a given network address string buffer is null-valued. More...
const char *	janus_network_address_string_from_buffer (const janus_network_address_string_buffer *b)
	Extract the human readable representation of a network address from a given buffer. More...
int	janus_network_string_is_valid_address (janus_network_query_options addr_type, const char *user_value)
	Test if a given IP address string is a valid address of the specified type. More...
int	janus_network_string_to_address (janus_network_query_options addr_type, const char *user_value, janus_network_address *result)
	Convert an IP address string to a janus_network_address instance. More...
int	janus_network_lookup_interface (const struct ifaddrs *ifas, const char *iface, janus_network_address *result)
	Convert an interface name or IP address to a janus_network_address instance. More...
int	janus_network_detect_local_ip (janus_network_query_options addr_type, janus_network_address *result)
	Helper method to find a valid local IP address, that is an address that can be used to communicate. More...
char *	janus_network_detect_local_ip_as_string (janus_network_query_options addr_type)
	Wrapper to janus_network_detect_local_ip that returns a string instead. More...

Detailed Description

IP address related utility functions.

Author

Johan Ouwerkerk jm.ou.nosp@m.werk.nosp@m.erk@g.nosp@m.mail.nosp@m..com

Copyright

GNU General Public License v3 Provides functions to query for network devices with a given device name or address. Devices may be looked up by either a device name or by the IPv4 or IPv6 address of the configured network interface. This functionality may be used to bind to user configurable network devices instead of relying on unpredictable implementation defined defaults. Parsing IPv4/IPv6 addresses is done using inet_pton(), making these functions generally robust against malformed input.

Core

Function Documentation

janus_network_address_from_sockaddr()

int janus_network_address_from_sockaddr	(	struct sockaddr *	s,
		janus_network_address *	a
	)

Convert a struct sockaddr to a janus_network_address.

Parameters

s	The struct sockaddr to convert
a	The address to write to

Returns

0 on success, or -EINVAL otherwise.

janus_network_address_is_null()

int janus_network_address_is_null

(

const janus_network_address *

a

)

Test if a given network address is null-valued.

Parameters

a	The address to check

Returns

A positive integer if the given address is null-valued, 0 otherwise.

See also

janus_network_address_nullify

janus_network_address_nullify()

void janus_network_address_nullify

(

janus_network_address *

a

)

Set the given network address to a null/nil value.

Parameters

a	The address to nullify. Nothing is done if the pointer is NULL itself.

See also

janus_network_address_is_null

janus_network_address_string_buffer_is_null()

int janus_network_address_string_buffer_is_null

(

const janus_network_address_string_buffer *

b

)

Test if a given network address string buffer is null-valued.

Parameters

b	The buffer to check

Returns

A positive integer if the given buffer is null-valued, 0 otherwise.

See also

janus_network_address_string_buffer_nullify

janus_network_address_string_buffer_nullify()

void janus_network_address_string_buffer_nullify

(

janus_network_address_string_buffer *

b

)

Set the given network address string buffer to a null/nil value.

Parameters

b	The address to nullify. Nothing is done if the pointer is NULL itself.

See also

janus_network_address_string_buffer_is_null

janus_network_address_string_from_buffer()

const char* janus_network_address_string_from_buffer

(

const janus_network_address_string_buffer *

b

)

Extract the human readable representation of a network address from a given buffer.

Parameters

b	The buffer containing the given network

Returns

A pointer to the human readable representation of the network address inside the given buffer, or NULL if the buffer is invalid or NULL.

See also

janus_network_address_to_string_buffer

janus_network_address_to_string_buffer()

int janus_network_address_to_string_buffer	(	const janus_network_address *	a,
		janus_network_address_string_buffer *	buf
	)

Convert the given network address to a form which can be used to extract a human readable network address from.

Parameters

a	The address to convert
buf	A buffer to contain the human readable form.

Returns

0 on success, or -EINVAL if any argument is NULL.

See also

janus_network_address

janus_network_address_string_buffer

janus_network_address_string_from_buffer

man 3 inet_ntop

janus_network_detect_local_ip()

int janus_network_detect_local_ip	(	janus_network_query_options	addr_type,
		janus_network_address *	result
	)

Helper method to find a valid local IP address, that is an address that can be used to communicate.

Parameters

addr_type	The type of address you're interested in (janus_network_query_options_ipv4, janus_network_query_options_ipv6 or janus_network_query_options_any_ip)
result	Pointer to a valid janus_network_address instance that will contain the result

Returns

0 in case of success, -EINVAL otherwise otherwise

janus_network_detect_local_ip_as_string()

char* janus_network_detect_local_ip_as_string

(

janus_network_query_options

addr_type

)

Wrapper to janus_network_detect_local_ip that returns a string instead.

Note

The string is allocated with g_strdup and so needs to be freed by the caller

Parameters

addr_type

The type of address you're interested in (janus_network_query_options_ipv4, janus_network_query_options_ipv6 or janus_network_query_options_any_ip)

Returns

0 in case of success, -EINVAL otherwise otherwise

janus_network_get_device_address()

int janus_network_get_device_address	(	const struct ifaddrs *	ifa,
		janus_network_address *	result
	)

Copies the IP address from a network interface description to the given result structure.

Returns

0 on success, or -EINVAL if any argument is NULL or the given network interface does not correspond to an IP address.

See also

janus_network_address

janus_network_get_devices_ipv4()

int janus_network_get_devices_ipv4	(	const struct ifaddrs *	ifa,
		const janus_network_query_config *	query,
		struct in_addr *	result
	)

Copies the IPv4 address from a network inteface description to the given result structure.

Parameters

ifa	The network interface description to grab the IPv4 address from. It should be obtained with janus_network_query_devices().
query	A description of the criteria to look for when determining whether or not a network interface is a match
result	Pointer to a structure to populate with the IPv4 address of the given network interface

Returns

0 on success, -EINVAL if any argument is NULL or the network interface description or the network device query do not correspond to an IPv4 configuration.

See also

man 7 ip

janus_network_query_devices

janus_network_get_devices_ipv6()

int janus_network_get_devices_ipv6	(	const struct ifaddrs *	ifa,
		const janus_network_query_config *	query,
		struct in6_addr *	result
	)

Copies the IPv6 address from a network inteface description to the given result structure.

Parameters

ifa	The network interface description to grab the IPv6 address from. It should be obtained with janus_network_query_devices().
query	A description of the criteria to look for when determining whether or not a network interface is a match
result	Pointer to a structure to populate with the IPv6 address of the given network interface

Returns

0 on success, -EINVAL if any argument is NULL or the network interface description or the network device query do not correspond to an IPv6 configuration.

See also

man 7 ipv6

janus_network_query_devices

janus_network_lookup_interface()

int janus_network_lookup_interface	(	const struct ifaddrs *	ifas,
		const char *	iface,
		janus_network_address *	result
	)

Convert an interface name or IP address to a janus_network_address instance.

Parameters

ifas	The list of interfaces to look into (e.g., as returned from getifaddrs)
iface	The interface name or IP address to look for
result	Pointer to a valid janus_network_address instance that will contain the result

Returns

0 in case of success, -EINVAL otherwise otherwise

janus_network_prepare_device_query()

int janus_network_prepare_device_query	(	const char *	user_value,
		const janus_network_query_options	query_mode,
		janus_network_query_config *	query
	)

Initialise a network device query.

Parameters

user_value	The user-supplied string which is supposed to describe either the device name or its IP address.
query_mode	(A mask of) Options describing the supported types of matches which should be accepted when performing a look up with this query. This can be used to restrict the query to 'by device name' or 'IPv4 only' type searches.
query	The query object to configure.

Returns

0 on success or -EINVAL if any of the arguments are NULL or the given value to look for does not correspond to a valid IPv4/IPv6 address and matching by name is disabled.

See also

janus_network_query_options

janus_network_prepare_device_query_default()

int janus_network_prepare_device_query_default	(	const char *	user_value,
		janus_network_query_config *	query
	)

Initialise a network device query with default query options. This function will Initialise the query to accept any supported match type.

Parameters

user_value	The user-supplied string which is supposed to describe either the device name or its IP address.
query	The query object to configure.

Returns

0 on success, or -EINVAL if any of the arguments are NULL

See also

janus_network_prepare_device_query

janus_network_query_devices()

const struct ifaddrs* janus_network_query_devices	(	const struct ifaddrs *	ifas,
		const janus_network_query_config *	query
	)

Look up network devices matching the given query. The first matching device is returned, so to find all matching devices simply pass the ifa_next of the returned device in a subsequent call to this function to find more matches.

Parameters

ifas	The first node of the list of network interfaces to search through. This should be obtained (indirectly) from getifaddrs().
query	A description of the criteria to look for when determining whether or not a network interface is a match.

Returns

a pointer to a node describing the matching network interface or NULL if no (further) match was found.

See also

man 3 getifaddrs

janus_network_string_is_valid_address()

int janus_network_string_is_valid_address	(	janus_network_query_options	addr_type,
		const char *	user_value
	)

Test if a given IP address string is a valid address of the specified type.

Parameters

addr_type	The type of address you're interested in (janus_network_query_options_ipv4, janus_network_query_options_ipv6 or janus_network_query_options_any_ip)
user_value	The IP address string to check

Returns

A positive integer if the given string is a valid address, 0 otherwise.

janus_network_string_to_address()

int janus_network_string_to_address	(	janus_network_query_options	addr_type,
		const char *	user_value,
		janus_network_address *	result
	)

Convert an IP address string to a janus_network_address instance.

Parameters

addr_type	The type of address you're interested in (janus_network_query_options_ipv4, janus_network_query_options_ipv6 or janus_network_query_options_any_ip)
user_value	The IP address string to check
result	Pointer to a valid janus_network_address instance that will contain the result

Returns

0 in case of success, -EINVAL otherwise otherwise