[Qemu-devel] [PULL 0/5] net: Add and use new function socket_set_fast_reuse

[Qemu-devel] [PULL 0/5] net: Add and use new function socket_set_fast_reuse

[Stefan Weil]

The following changes since commit a684f3cf9b9b9c3cb82be87aafc463de8974610c:

  Merge remote-tracking branch 'kraxel/seabios-1.7.3.2' into staging (2013-09-30 17:15:27 -0500)

are available in the git repository at:


  git://qemu.weilnetz.de/qemu.git mingw

for you to fetch changes up to 04fd1c789677fe121cb9546c652d088c994477fb:

  util: call socket_set_fast_reuse instead of setting SO_REUSEADDR (2013-10-02 19:20:31 +0200)

----------------------------------------------------------------
Sebastian Ottlik (5):
      util: add socket_set_fast_reuse function which will replace setting SO_REUSEADDR
      gdbstub: call socket_set_fast_reuse instead of setting SO_REUSEADDR
      net: call socket_set_fast_reuse instead of setting SO_REUSEADDR
      slirp: call socket_set_fast_reuse instead of setting SO_REUSEADDR
      util: call socket_set_fast_reuse instead of setting SO_REUSEADDR

 gdbstub.c              |    6 ++----
 include/qemu/sockets.h |    1 +
 net/socket.c           |   19 ++++++++++---------
 slirp/misc.c           |    3 +--
 slirp/socket.c         |    4 +---
 slirp/tcp_subr.c       |    6 ++----
 slirp/udp.c            |    4 ++--
 util/oslib-posix.c     |   12 ++++++++++++
 util/oslib-win32.c     |   10 ++++++++++
 util/qemu-sockets.c    |    6 +++---
 10 files changed, 44 insertions(+), 27 deletions(-)

[PULL 1/5] util: add socket_set_fast_reuse function which will
[PULL 2/5] gdbstub: call socket_set_fast_reuse instead of setting
[PULL 3/5] net: call socket_set_fast_reuse instead of setting
[PULL 4/5] slirp: call socket_set_fast_reuse instead of setting
[PULL 5/5] util: call socket_set_fast_reuse instead of setting

[Qemu-devel] [PULL 1/5] util: add socket_set_fast_reuse function which will replace setting SO_REUSEADDR

[Stefan Weil]

From: Sebastian Ottlik <ottlik@fzi.de>

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>
---
 include/qemu/sockets.h |    1 +
 util/oslib-posix.c     |   12 ++++++++++++
 util/oslib-win32.c     |   10 ++++++++++
 3 files changed, 23 insertions(+)

diff --git a/include/qemu/sockets.h b/include/qemu/sockets.h
index c5174d7..45588d7 100644
--- a/include/qemu/sockets.h
+++ b/include/qemu/sockets.h
@@ -39,6 +39,7 @@ 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);
 
diff --git a/util/oslib-posix.c b/util/oslib-posix.c
index 253bc3d..e00a44c 100644
--- a/util/oslib-posix.c
+++ b/util/oslib-posix.c
@@ -157,6 +157,18 @@ void qemu_set_nonblock(int fd)
     fcntl(fd, F_SETFL, f | O_NONBLOCK);
 }
 
+int socket_set_fast_reuse(int fd)
+{
+    int val = 1, ret;
+
+    ret = setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
+                     (const char *)&val, sizeof(val));
+
+    assert(ret == 0);
+
+    return ret;
+}
+
 void qemu_set_cloexec(int fd)
 {
     int f;
diff --git a/util/oslib-win32.c b/util/oslib-win32.c
index 983b7a2..776ccfa 100644
--- a/util/oslib-win32.c
+++ b/util/oslib-win32.c
@@ -124,6 +124,16 @@ void qemu_set_nonblock(int fd)
     qemu_fd_register(fd);
 }
 
+int socket_set_fast_reuse(int fd)
+{
+    /* Enabling the reuse of an endpoint that was used by a socket still in
+     * TIME_WAIT state is usually performed by setting SO_REUSEADDR. On Windows
+     * fast reuse is the default and SO_REUSEADDR does strange things. So we
+     * don't have to do anything here. More info can be found at:
+     * http://msdn.microsoft.com/en-us/library/windows/desktop/ms740621.aspx */
+    return 0;
+}
+
 int inet_aton(const char *cp, struct in_addr *ia)
 {
     uint32_t addr = inet_addr(cp);
-- 
1.7.10.4

[Qemu-devel] [PULL 2/5] gdbstub: call socket_set_fast_reuse instead of setting SO_REUSEADDR

[Stefan Weil]

From: Sebastian Ottlik <ottlik@fzi.de>

SO_REUSEADDR should be avoided on Windows but is desired on other operating
systems. So instead of setting it we call socket_set_fast_reuse that will result
in the appropriate behaviour on all operating systems.

Signed-off-by: Sebastian Ottlik <ottlik@fzi.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Weil <sw@weilnetz.de>
---
 gdbstub.c |    6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/gdbstub.c b/gdbstub.c
index 2b7f22b..0e5a3f5 100644
--- a/gdbstub.c
+++ b/gdbstub.c
@@ -1553,7 +1553,7 @@ static void gdb_accept(void)
 static int gdbserver_open(int port)
 {
     struct sockaddr_in sockaddr;
-    int fd, val, ret;
+    int fd, ret;
 
     fd = socket(PF_INET, SOCK_STREAM, 0);
     if (fd < 0) {
@@ -1564,9 +1564,7 @@ static int gdbserver_open(int port)
     fcntl(fd, F_SETFD, FD_CLOEXEC);
 #endif
 
-    /* allow fast reuse */
-    val = 1;
-    qemu_setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
+    socket_set_fast_reuse(fd);
 
     sockaddr.sin_family = AF_INET;
     sockaddr.sin_port = htons(port);
-- 
1.7.10.4

[Qemu-devel] [PULL 3/5] net: call socket_set_fast_reuse instead of setting SO_REUSEADDR

[Stefan Weil]

From: Sebastian Ottlik <ottlik@fzi.de>

SO_REUSEADDR should be avoided on Windows but is desired on other operating
systems. So instead of setting it we call socket_set_fast_reuse that will result
in the appropriate behaviour on all operating systems.

An exception to this rule are multicast sockets where it is sensible to have
multiple sockets listen on the same ip and port and we should set SO_REUSEADDR
on windows.

Signed-off-by: Sebastian Ottlik <ottlik@fzi.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Weil <sw@weilnetz.de>
---
 net/socket.c |   19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/net/socket.c b/net/socket.c
index e61309d..fb21e20 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -262,6 +262,11 @@ static int net_socket_mcast_create(struct sockaddr_in *mcastaddr, struct in_addr
         return -1;
     }
 
+    /* Allow multiple sockets to bind the same multicast ip and port by setting
+     * SO_REUSEADDR. This is the only situation where SO_REUSEADDR should be set
+     * on windows. Use socket_set_fast_reuse otherwise as it sets SO_REUSEADDR
+     * only on posix systems.
+     */
     val = 1;
     ret = qemu_setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
     if (ret < 0) {
@@ -510,7 +515,7 @@ static int net_socket_listen_init(NetClientState *peer,
     NetClientState *nc;
     NetSocketState *s;
     struct sockaddr_in saddr;
-    int fd, val, ret;
+    int fd, ret;
 
     if (parse_host_port(&saddr, host_str) < 0)
         return -1;
@@ -522,9 +527,7 @@ static int net_socket_listen_init(NetClientState *peer,
     }
     qemu_set_nonblock(fd);
 
-    /* allow fast reuse */
-    val = 1;
-    qemu_setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &val, sizeof(val));
+    socket_set_fast_reuse(fd);
 
     ret = bind(fd, (struct sockaddr *)&saddr, sizeof(saddr));
     if (ret < 0) {
@@ -645,7 +648,7 @@ static int net_socket_udp_init(NetClientState *peer,
                                  const char *lhost)
 {
     NetSocketState *s;
-    int fd, val, ret;
+    int fd, ret;
     struct sockaddr_in laddr, raddr;
 
     if (parse_host_port(&laddr, lhost) < 0) {
@@ -661,11 +664,9 @@ static int net_socket_udp_init(NetClientState *peer,
         perror("socket(PF_INET, SOCK_DGRAM)");
         return -1;
     }
-    val = 1;
-    ret = qemu_setsockopt(fd, SOL_SOCKET, SO_REUSEADDR,
-                          &val, sizeof(val));
+
+    ret = socket_set_fast_reuse(fd);
     if (ret < 0) {
-        perror("setsockopt(SOL_SOCKET, SO_REUSEADDR)");
         closesocket(fd);
         return -1;
     }
-- 
1.7.10.4

[Qemu-devel] [PULL 4/5] slirp: call socket_set_fast_reuse instead of setting SO_REUSEADDR

[Stefan Weil]

From: Sebastian Ottlik <ottlik@fzi.de>

SO_REUSEADDR should be avoided on Windows but is desired on other operating
systems. So instead of setting it we call socket_set_fast_reuse that will result
in the appropriate behaviour on all operating systems.

Signed-off-by: Sebastian Ottlik <ottlik@fzi.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Weil <sw@weilnetz.de>
---
 slirp/misc.c     |    3 +--
 slirp/socket.c   |    4 +---
 slirp/tcp_subr.c |    6 ++----
 slirp/udp.c      |    4 ++--
 4 files changed, 6 insertions(+), 11 deletions(-)

diff --git a/slirp/misc.c b/slirp/misc.c
index c0d4899..6c1636f 100644
--- a/slirp/misc.c
+++ b/slirp/misc.c
@@ -212,8 +212,7 @@ fork_exec(struct socket *so, const char *ex, int do_pty)
                     so->s = accept(s, (struct sockaddr *)&addr, &addrlen);
                 } while (so->s < 0 && errno == EINTR);
                 closesocket(s);
-                opt = 1;
-                qemu_setsockopt(so->s, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(int));
+                socket_set_fast_reuse(so->s);
                 opt = 1;
                 qemu_setsockopt(so->s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(int));
 		qemu_set_nonblock(so->s);
diff --git a/slirp/socket.c b/slirp/socket.c
index 25d60e7..37ac5cf 100644
--- a/slirp/socket.c
+++ b/slirp/socket.c
@@ -627,9 +627,7 @@ tcp_listen(Slirp *slirp, uint32_t haddr, u_int hport, uint32_t laddr,
 	addr.sin_port = hport;
 
 	if (((s = qemu_socket(AF_INET,SOCK_STREAM,0)) < 0) ||
-#ifndef _WIN32
-	    (qemu_setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(int)) < 0) ||
-#endif
+	    (socket_set_fast_reuse(s) < 0) ||
 	    (bind(s,(struct sockaddr *)&addr, sizeof(addr)) < 0) ||
 	    (listen(s,1) < 0)) {
 		int tmperrno = errno; /* Don't clobber the real reason we failed */
diff --git a/slirp/tcp_subr.c b/slirp/tcp_subr.c
index 043f28f..7571c5a 100644
--- a/slirp/tcp_subr.c
+++ b/slirp/tcp_subr.c
@@ -337,8 +337,7 @@ int tcp_fconnect(struct socket *so)
     struct sockaddr_in addr;
 
     qemu_set_nonblock(s);
-    opt = 1;
-    qemu_setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
+    socket_set_fast_reuse(s);
     opt = 1;
     qemu_setsockopt(s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(opt));
 
@@ -426,8 +425,7 @@ void tcp_connect(struct socket *inso)
         return;
     }
     qemu_set_nonblock(s);
-    opt = 1;
-    qemu_setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(int));
+    socket_set_fast_reuse(s);
     opt = 1;
     qemu_setsockopt(s, SOL_SOCKET, SO_OOBINLINE, &opt, sizeof(int));
     socket_set_nodelay(s);
diff --git a/slirp/udp.c b/slirp/udp.c
index b105f87..8cc6cb6 100644
--- a/slirp/udp.c
+++ b/slirp/udp.c
@@ -354,7 +354,7 @@ udp_listen(Slirp *slirp, uint32_t haddr, u_int hport, uint32_t laddr,
 {
 	struct sockaddr_in addr;
 	struct socket *so;
-	socklen_t addrlen = sizeof(struct sockaddr_in), opt = 1;
+	socklen_t addrlen = sizeof(struct sockaddr_in);
 
 	so = socreate(slirp);
 	if (!so) {
@@ -372,7 +372,7 @@ udp_listen(Slirp *slirp, uint32_t haddr, u_int hport, uint32_t laddr,
 		udp_detach(so);
 		return NULL;
 	}
-	qemu_setsockopt(so->s, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(int));
+	socket_set_fast_reuse(so->s);
 
 	getsockname(so->s,(struct sockaddr *)&addr,&addrlen);
 	so->so_fport = addr.sin_port;
-- 
1.7.10.4

[Qemu-devel] [PULL 5/5] util: call socket_set_fast_reuse instead of setting SO_REUSEADDR

[Stefan Weil]

From: Sebastian Ottlik <ottlik@fzi.de>

SO_REUSEADDR should be avoided on Windows but is desired on other operating
systems. So instead of setting it we call socket_set_fast_reuse that will result
in the appropriate behaviour on all operating systems.

Signed-off-by: Sebastian Ottlik <ottlik@fzi.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Weil <sw@weilnetz.de>
---
 util/qemu-sockets.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/util/qemu-sockets.c b/util/qemu-sockets.c
index 095716e..6b97dc1 100644
--- a/util/qemu-sockets.c
+++ b/util/qemu-sockets.c
@@ -155,7 +155,7 @@ int inet_listen_opts(QemuOpts *opts, int port_offset, Error **errp)
             continue;
         }
 
-        qemu_setsockopt(slisten, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
+        socket_set_fast_reuse(slisten);
 #ifdef IPV6_V6ONLY
         if (e->ai_family == PF_INET6) {
             /* listen on both ipv4 and ipv6 */
@@ -274,7 +274,7 @@ static int inet_connect_addr(struct addrinfo *addr, bool *in_progress,
         error_set_errno(errp, errno, QERR_SOCKET_CREATE_FAILED);
         return -1;
     }
-    qemu_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
+    socket_set_fast_reuse(sock);
     if (connect_state != NULL) {
         qemu_set_nonblock(sock);
     }
@@ -455,7 +455,7 @@ int inet_dgram_opts(QemuOpts *opts, Error **errp)
         error_set_errno(errp, errno, QERR_SOCKET_CREATE_FAILED);
         goto err;
     }
-    qemu_setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));
+    socket_set_fast_reuse(sock);
 
     /* bind socket */
     if (bind(sock, local->ai_addr, local->ai_addrlen) < 0) {
-- 
1.7.10.4