A listening socket can be enabled with the sockopt
TCP_DEFER_ACCEPT. This informs the kernel to not call the user-land
accept() until real data has been written to the socket.
A new flag LEV_OPT_DEFERRED_ACCEPT has been introduced to
automatically set this option. Optionally
evutil_make_tcp_listen_socket_deferred() can be called manually.
(Tweaked slightly by nickm.)
Linux provides some features that allow avoiding extra calls to
fcntl when creating new nonblocking/close-on-exec sockets, so
we can add wrapper functions to emulate those when they are not
available.
Additionally, even when we are emulating those functions, we can
take a fast path that cuts our fcntl calls in half: we don't need to
look up the previous value of a file's flags when we have just
created it.
- redeclaration of dst_size
- arpa/inet.h requires netinet/in.h first
- don't use a local with the same name as a global - it isn't needed so
remove it
First of all, it is totally okay to have an address end with .255,
depending on what your netmask is, so we shouldn't reject a local
address if it ends with .255.
Second, our check for ending with .255 was broken. So was our check
for class-d addresses.
Found by Dave Hart.
It is (in my benchmarks) way faster than _ftime, though the
conversion process is not so straightforward. In theory, it can
have a better granularity too, though in practice who knows what
you're getting.
Remember, the code
int is_less_than(int a, unsigned b) {
return a < b;
}
is buggy, since the C integer promotion rules basically turn it into
int is_less_than(int a, unsigned b) {
return ((unsigned)a) < b;
}
and we really want something closer to
int is_less_than(int a, unsigned b) {
return a < 0 || ((unsigned)a) < b;
}
.
Suggested by an example from Ralph Castain
Remember that in a fit of ANSI C compliance, Microsoft decided to
screw portability by renaming basically all the functions in unistd.h to
get prefixed with an understore.
For some reason, mingw didn't seem to mind, but at least some people's
compilers did: see bug 3044490.
This patch splits the formerly windows-only case of evutil_socketpair()
into an (internal-use-only) function named evutil_ersatz_socketpair(), and
makes it build and work right on non-Windows hosts.
We need this for convenience to test sendfile on solaris, where socketpair
can't give you an AF_INET pair, and sendfile() won't work on AF_UNIX.
Everybody but Linux documents this as taking an int, and Linux is
very tolerant of getting an int instead. If it weren't, everybody
doing fcntl(fd,F_SETFL,O_NONBLOCK) would break, since the glibc
headers define O_NONBLOCK as an int literal.
