NAME
bindresvport,
bindresvport_sa —
bind a socket to a reserved privileged IP port
LIBRARY
Standard C Library (libc, -lc)
SYNOPSIS
#include <sys/types.h>
#include <rpc/rpc.h>
int
bindresvport(
int
sd,
struct sockaddr_in
*sin);
int
bindresvport_sa(
int
sd,
struct sockaddr
*sa);
DESCRIPTION
bindresvport() and
bindresvport_sa() are
used to bind a socket descriptor to a reserved privileged IP port, that is, a
port number in the range 0-1023. The routine returns 0 if it is successful,
otherwise -1 is returned and
errno set to reflect the
cause of the error.
If
sin is a pointer to a
struct
sockaddr_in then the appropriate fields in the structure should be
defined. Note that
sin->sin_family must be
initialized to the address family of the socket, passed by
sd. If
sin->sin_port is
‘0’ then a port (in the range 600-1023) will be chosen, and if
bind(2) is successful, the
sin->sin_port will be updated to contain the
allocated port.
If
sin is the
NULL
pointer, a port
will be allocated (as above). However, there is no way for
bindresvport() to return the allocated port in this case.
getsockname(2) can be used
to determine the assigned port.
Only root can bind to a privileged port; this call will fail for any other
users.
Function prototype of
bindresvport() is biased to
AF_INET
socket.
bindresvport_sa()
acts exactly the same, with more neutral function prototype. Note that both
functions behave exactly the same, and both support
AF_INET6
sockets as well as
AF_INET
sockets.
RETURN VALUES
If the bind is successful, a 0 value is returned. A return value of -1 indicates
an error, which is further specified in the global
errno.
ERRORS
-
-
- [
EPFNOSUPPORT
]
- If second argument was supplied, and address family did not
match between arguments.
bindresvport() may also fail and set
errno for any of the errors specified for the calls
bind(2),
getsockopt(2), or
setsockopt(2).
SEE ALSO
bind(2),
getsockname(2),
getsockopt(2),
setsockopt(2),
ip(4)