qemu-e2k/include/qemu/sockets.h
Sebastian Ottlik 606600a176 util: add socket_set_fast_reuse function which will replace setting SO_REUSEADDR
If a socket is closed it remains in TIME_WAIT state for some time. On operating
systems using BSD sockets the endpoint of the socket may not be reused while in
this state unless SO_REUSEADDR was set on the socket. On windows on the other
hand the default behaviour is to allow reuse (i.e. identical to SO_REUSEADDR on
other operating systems) and setting SO_REUSEADDR on a socket allows it to be
bound to a endpoint even if the endpoint is already used by another socket
independently of the other sockets state. This can even result in undefined
behaviour.

Many sockets used by QEMU should not block the use of their endpoint after being
closed while they are still in TIME_WAIT state. Currently QEMU sets SO_REUSEADDR
for such sockets, which can lead to problems on Windows. This patch introduces
the function socket_set_fast_reuse that should be used instead of setting
SO_REUSEADDR when fast socket reuse is desired and behaves correctly on all
operating systems.

As a failure of this function can only be caused by bad QEMU internal errors, an
assertion handles these situations. The return value is still passed on, to
minimize changes in client code and prevent unused variable warnings if NDEBUG
is defined.

Signed-off-by: Sebastian Ottlik <ottlik@fzi.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Weil <sw@weilnetz.de>
2013-10-02 19:20:31 +02:00

85 lines
2.8 KiB
C

/* headers to use the BSD sockets */
#ifndef QEMU_SOCKET_H
#define QEMU_SOCKET_H
#ifdef _WIN32
#include <windows.h>
#include <winsock2.h>
#include <ws2tcpip.h>
#define socket_error() WSAGetLastError()
int inet_aton(const char *cp, struct in_addr *ia);
#else
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/tcp.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <sys/un.h>
#define socket_error() errno
#define closesocket(s) close(s)
#endif /* !_WIN32 */
#include "qemu/option.h"
#include "qapi/error.h"
#include "qapi/qmp/qerror.h"
extern QemuOptsList socket_optslist;
/* misc helpers */
int qemu_socket(int domain, int type, int protocol);
int qemu_accept(int s, struct sockaddr *addr, socklen_t *addrlen);
int socket_set_cork(int fd, int v);
int socket_set_nodelay(int fd);
void qemu_set_block(int fd);
void qemu_set_nonblock(int fd);
int socket_set_fast_reuse(int fd);
int send_all(int fd, const void *buf, int len1);
int recv_all(int fd, void *buf, int len1, bool single_read);
/* callback function for nonblocking connect
* valid fd on success, negative error code on failure
*/
typedef void NonBlockingConnectHandler(int fd, void *opaque);
InetSocketAddress *inet_parse(const char *str, Error **errp);
int inet_listen_opts(QemuOpts *opts, int port_offset, Error **errp);
int inet_listen(const char *str, char *ostr, int olen,
int socktype, int port_offset, Error **errp);
int inet_connect_opts(QemuOpts *opts, Error **errp,
NonBlockingConnectHandler *callback, void *opaque);
int inet_connect(const char *str, Error **errp);
int inet_nonblocking_connect(const char *str,
NonBlockingConnectHandler *callback,
void *opaque, Error **errp);
int inet_dgram_opts(QemuOpts *opts, Error **errp);
const char *inet_strfamily(int family);
int unix_listen_opts(QemuOpts *opts, Error **errp);
int unix_listen(const char *path, char *ostr, int olen, Error **errp);
int unix_connect_opts(QemuOpts *opts, Error **errp,
NonBlockingConnectHandler *callback, void *opaque);
int unix_connect(const char *path, Error **errp);
int unix_nonblocking_connect(const char *str,
NonBlockingConnectHandler *callback,
void *opaque, Error **errp);
SocketAddress *socket_parse(const char *str, Error **errp);
int socket_connect(SocketAddress *addr, Error **errp,
NonBlockingConnectHandler *callback, void *opaque);
int socket_listen(SocketAddress *addr, Error **errp);
int socket_dgram(SocketAddress *remote, SocketAddress *local, Error **errp);
/* Old, ipv4 only bits. Don't use for new code. */
int parse_host_port(struct sockaddr_in *saddr, const char *str);
int socket_init(void);
#endif /* QEMU_SOCKET_H */