GETSOURCEFILTER(3SOCKET)GETSOURCEFILTER(3SOCKET)NAME
getsourcefilter, setsourcefilter, getipv4sourcefilter, setipv4source‐
filter - retrieve and set a socket's multicast filter
SYNOPSIS
cc [ flag... ] file... -lsocket [ library... ]
#include <netinet/in.h>
int getsourcefilter(int s, uint32_t interface,
struct sockaddr *group, socklen_t grouplen, uint32_t *fmode,
uint_t *numsrc, struct sockaddr_storage *slist);
int setsourcefilter(int s, uint32_t interface,
struct sockaddr *group, socklen_t grouplen, uint32_t fmode,
uint_t numsrc, struct sockaddr_storage *slist);
int getipv4sourcefilter(int s, struct in_addr interface,
struct in_addr group, uint32_t *fmode, uint32_t *numsrc,
struct in_addr *slist);
int setipv4sourcefilter(int s, struct in_addr interface,
struct in_addr group,uint32_t fmode, uint32_t numsrc,
struct in_addr *slist);
DESCRIPTION
These functions allow applications to retrieve and modify the multicast
filtering state for a tuple consisting of socket, interface, and multi‐
cast group values.
A multicast filter is described by a filter mode, which is MODE_INCLUDE
or MODE_EXCLUDE, and a list of source addresses which are filtered. If
a group is simply joined with no source address restrictions, the fil‐
ter mode is MODE_EXCLUDE and the source list is empty.
The getsourcefilter() and setsourcefilter() functions are protocol-
independent. They can be used on either PF_INET or PF_INET6 sockets.
The getipv4sourcefilter() and setipv4sourcefilter() functions are
IPv4-specific. They must be used only on PF_INET sockets.
For the protocol-independent functions, the first four arguments iden‐
tify the socket, interface, multicast group tuple values. The argument
s is an open socket of type SOCK_DGRAM or SOCK_RAW. The interface argu‐
ment is the interface index. The interface name can be mapped to the
index using if_nametoindex(3SOCKET). The group points to either a sock‐
addr_in containing an IPv4 multicast address if the socket is PF_INET
or a sockaddr_in6 containing an IPv6 multicast address if the socket is
PF_INET6. The grouplen is the size of the structure pointed to by
group.
For the IPv4-specific functions, the first three arguments identify the
same socket, interface, multicast group tuple values. The argument s is
an open socket of type SOCK_DGRAM or SOCK_RAW and protocol family
PF_INET. The interface argument is the IPv4 address assigned to the
local interface. The group argument is the IPv4 multicast address.
The getsourcefilter() and getipv4sourcefilter() functions retrieve the
current filter for the given tuple consisting of socket, interface, and
multicast group values. On successful return, fmode contains either
MODE_INCLUDE or MODE_EXCLUDE, indicating the filter mode. On input, the
numsrc argument holds the number of addresses that can fit in the slist
array. On return, slist contains as many addresses as fit, while num‐
src contains the total number of source addresses in the filter. It is
possible that numsrc can contain a number larger than the number of
addresses in the slist array. An application might determine the
required buffer size by calling getsourcefilter() with numsrc contain‐
ing 0 and slist a NULL pointer. On return, numsrc contains the number
of elements that the slist buffer must be able to hold. Alternatively,
the maximum number of source addresses allowed by this implementation
is defined in <netinet/in.h>:
#define MAX_SRC_FILTER_SIZE 64
The setsourcefilter() and setipv4sourcefilter functions replace the
current filter with the filter specified in the arguments fmode, num‐
src, and slist. The fmode argument must be set to either MODE_INCLUDE
or MODE_EXCLUDE. The numsrc argument is the number of addresses in the
slist array. The slist argument points to the array of source addresses
to be included or excluded, depending on the fmode value.
RETURN VALUES
If successful, all four functions return 0. Otherwise, they return −1
and set errno to indicate the error.
ERRORS
These functions will fail if:
EBADF
The s argument is not a valid descriptor.
EAFNOSUPPORT
The address family of the passed-in sockaddr is not
AF_INET or AF_INET6.
ENOPROTOOPT
The socket s is not of type SOCK_DGRAM or SOCK_RAW.
ENOPROTOOPT
The address family of the group parameter does not
match the protocol family of the socket.
ENOSR
Insufficient STREAMS resources available for the opera‐
tion to complete.
ENXIO
The interface argument, either an index or an IPv4
address, does not identify a valid interface.
The getsourcefilter() and getipv4sourcefilter() functions will fail if:
EADDRNOTAVAIL
The tuple consisting of socket, interface, and multi‐
cast group values does not exist; group is not being
listened to on interface by socket.
The functions setsourcefilter()and setipv4sourcefilter() can fail in
the following additional case:
ENOBUFS
The source filter list is larger than that allowed by the
implementation.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌────────────────────┬─────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├────────────────────┼─────────────────┤
│Interface Stability │ Committed │
├────────────────────┼─────────────────┤
│MT-Level │ Safe │
└────────────────────┴─────────────────┘
SEE ALSOif_nametoindex(3SOCKET), socket(3SOCKET), attributes(5)
RFC 3678
Aug 20, 2007 GETSOURCEFILTER(3SOCKET)