int
getpeername(
int s
, struct sockaddr * restrict name
, socklen_t * restrict namelen
)
)
returns the name of the peer connected to
socket
s
.
One common use occurs when a process inherits an open socket, such as
TCP servers forked from
inetd(8).
In this scenario,
getpeername(
)
is used to determine the connecting client's IP address.
getpeername()
takes three parameters:
s
contains the file descriptor of the socket whose peer should be looked up.
name
points to a
sockaddr
structure that will hold the address information for the connected peer.
Normal use requires one to use a structure
specific to the protocol family in use, such as
sockaddr_in
(IPv4) or
sockaddr_in6
(IPv6), cast to a (struct sockaddr *).
For greater portability, especially with the newer protocol families, the new
struct
sockaddr_storage
should be used.
sockaddr_storage
is large enough to hold any of the other sockaddr_* variants.
On return, it can be cast to the correct sockaddr type,
based on the protocol family contained in its ss_family field.
namelen
indicates the amount of space pointed to by
name
,
in bytes.
If address information for the local end of the socket is required, the getsockname(2) function should be used instead.
If
name
does not point to enough space to hold the entire socket address, the
result will be truncated to
namelen
bytes.
namelen
is set to the actual size of the socket address returned in
name
.
Otherwise,
errno
is set and a value of -1 is returned.
EBADF
]
s
is not a valid descriptor.
ENOTSOCK
]
s
is a file, not a socket.
ENOTCONN
]
ENOBUFS
]
EFAULT
]
name
parameter points to memory not in a valid part of the
process address space.
)
function call appeared in
4.2BSD.