udpfromto.c File Reference

API for sending and receiving packets on unconnected UDP sockets. More...

#include <freeradius-devel/util/udpfromto.h>
#include <fcntl.h>

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Macros
#define	SOL_IP   IPPROTO_IP

Functions
int	recvfromto (int fd, void *buf, size_t len, int flags, int *ifindex, struct sockaddr *from, socklen_t *from_len, struct sockaddr *to, socklen_t *to_len, fr_time_t *when)
	Read a packet from a file descriptor, retrieving additional header information. More...
int	sendfromto (int fd, void *buf, size_t len, int flags, int ifindex, struct sockaddr *from, socklen_t from_len, struct sockaddr *to, socklen_t to_len)
	Send packet via a file descriptor, setting the src address and outbound interface. More...
int	udpfromto_init (int s, int af)

Detailed Description

API for sending and receiving packets on unconnected UDP sockets.

Like recvfrom, but also stores the destination IP address. Useful on multihomed hosts.

Copyright

2007 Alan DeKok (aland.nosp@m.@dep.nosp@m.loyin.nosp@m.grad.nosp@m.ius.c.nosp@m.om)

2002 Miquel van Smoorenburg

Definition in file udpfromto.c.

Macro Definition Documentation

SOL_IP

#define SOL_IP   IPPROTO_IP

Definition at line 41 of file udpfromto.c.

Function Documentation

recvfromto()

int recvfromto	(	int	fd,
		void *	buf,
		size_t	len,
		int	flags,
		int *	ifindex,
		struct sockaddr *	from,
		socklen_t *	from_len,
		struct sockaddr *	to,
		socklen_t *	to_len,
		fr_time_t *	when
	)

Read a packet from a file descriptor, retrieving additional header information.

Abstracts away the complexity of using the complexity of using recvmsg().

In addition to reading data from the file descriptor, the src and dst addresses and the receiving interface index are retrieved. This enables us to send replies using the correct IP interface, in the case where the server is multihomed. This is not normally possible on unconnected datagram sockets.

Parameters

[in]	fd	The file descriptor to read from.
[out]	buf	Where to write the received datagram data.
[in]	len	of buf.
[in]	flags	passed unmolested to recvmsg.
[out]	ifindex	The interface which received the datagram (may be NULL). Will only be populated if to is not NULL.
[out]	from	Where to write the source address.
[in]	from_len	Length of the structure pointed to by from.
[out]	to	Where to write the destination address. If NULL recvmsg() will be used instead.
[in]	to_len	Length of the structure pointed to by to.
[out]	when	the packet was received (may be NULL). If SO_TIMESTAMP is not available or SO_TIMESTAMP Was not set on the socket, then another method will be used instead to get the time.

Returns

• 0 on success.
• -1 on failure.

Definition at line 191 of file udpfromto.c.

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sendfromto()

int sendfromto	(	int	fd,
		void *	buf,
		size_t	len,
		int	flags,
		int	ifindex,
		struct sockaddr *	from,
		socklen_t	from_len,
		struct sockaddr *	to,
		socklen_t	to_len
	)

Send packet via a file descriptor, setting the src address and outbound interface.

Abstracts away the complexity of using the complexity of using sendmsg().

Parameters

[in]	fd	The file descriptor to write to.
[in]	buf	Where to read datagram data from.
[in]	len	of datagram data.
[in]	flags	passed unmolested to sendmsg.
[in]	ifindex	The interface on which to send the datagram. If automatic interface selection is desired, value should be 0.
[in]	from	The source address.
[in]	from_len	Length of the structure pointed to by from.
[in]	to	The destination address.
[in]	to_len	Length of the structure pointed to by to.

Returns

• 0 on success.
• -1 on failure.

Definition at line 391 of file udpfromto.c.

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udpfromto_init()

int udpfromto_init	(	int	s,
		int	af
	)

Definition at line 92 of file udpfromto.c.

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