EACCES The user tried to execute an operation without the
necessary permissions. These include: sending a packet to
a broadcast address without having the SO_BROADCAST flag
set; sending a packet via a prohibit route; modifying
firewall settings without superuser privileges (the
CAP_NET_ADMIN capability); binding to a privileged port
without superuser privileges (the CAP_NET_BIND_SERVICE
capability).
EADDRINUSE
Tried to bind to an address already in use.
EADDRNOTAVAIL
A nonexistent interface was requested or the requested
source address was not local.
EAGAIN Operation on a nonblocking socket would block.
EALREADY
A connection operation on a nonblocking socket is already
in progress.
ECONNABORTED
A connection was closed during an accept(2).
EHOSTUNREACH
No valid routing table entry matches the destination
address. This error can be caused by an ICMP message from
a remote router or for the local routing table.
EINVAL Invalid argument passed. For send operations this can be
caused by sending to a blackhole route.
EISCONN
connect(2) was called on an already connected socket.
EMSGSIZE
Datagram is bigger than an MTU on the path and it cannot
be fragmented.
ENOBUFS, ENOMEM
Not enough free memory. This often means that the memory
allocation is limited by the socket buffer limits, not by
the system memory, but this is not 100% consistent.
ENOENT SIOCGSTAMP was called on a socket where no packet arrived.
ENOPKG A kernel subsystem was not configured.
ENOPROTOOPT and EOPNOTSUPP
Invalid socket option passed.
ENOTCONN
The operation is defined only on a connected socket, but
the socket wasn't connected.
EPERM User doesn't have permission to set high priority, change
configuration, or send signals to the requested process or
group.
EPIPE The connection was unexpectedly closed or shut down by the
other end.
ESOCKTNOSUPPORT
The socket is not configured or an unknown socket type was
requested.
Other errors may be generated by the overlaying protocols; see
tcp(7), raw(7), udp(7), and socket(7).
