[Qemu-devel] [RFC PATCH v5 05/14] net: port socket to GSource

[Liu Ping Fan <qemulist@gmail.com>]

From: Liu Ping Fan <pingfank@linux.vnet.ibm.com>

Port NetSocketState onto NetClientSource. The only thing specail is that
owning to the socket's state machine changes, we need to change the handler.
We implement that by destroy the old NetClientSource and attach a new one
with NetSocketState.

Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
---
 net/socket.c |  196 +++++++++++++++++++++++++++++++++++++++++++++++-----------
 1 files changed, 159 insertions(+), 37 deletions(-)

diff --git a/net/socket.c b/net/socket.c
index 396dc8c..abdb809 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -31,6 +31,8 @@
 #include "qemu/option.h"
 #include "qemu/sockets.h"
 #include "qemu/iov.h"
+#include "util/event_gsource.h"
+
 
 typedef struct NetSocketState {
     NetClientState nc;
@@ -42,13 +44,15 @@ typedef struct NetSocketState {
     unsigned int send_index;      /* number of bytes sent (only SOCK_STREAM) */
     uint8_t buf[4096];
     struct sockaddr_in dgram_dst; /* contains inet host and port destination iff connectionless (SOCK_DGRAM) */
-    IOHandler *send_fn;           /* differs between SOCK_STREAM/SOCK_DGRAM */
     bool read_poll;               /* waiting to receive data? */
     bool write_poll;              /* waiting to transmit data? */
+    EventGSource *nsrc;
 } NetSocketState;
 
-static void net_socket_accept(void *opaque);
 static void net_socket_writable(void *opaque);
+static gboolean net_socket_listen_handler(gpointer data);
+static gboolean net_socket_establish_handler(gpointer data);
+
 
 /* Only read packets from socket when peer can receive them */
 static int net_socket_can_send(void *opaque)
@@ -58,25 +62,14 @@ static int net_socket_can_send(void *opaque)
     return qemu_can_send_packet(&s->nc);
 }
 
-static void net_socket_update_fd_handler(NetSocketState *s)
-{
-    qemu_set_fd_handler2(s->fd,
-                         s->read_poll  ? net_socket_can_send : NULL,
-                         s->read_poll  ? s->send_fn : NULL,
-                         s->write_poll ? net_socket_writable : NULL,
-                         s);
-}
-
 static void net_socket_read_poll(NetSocketState *s, bool enable)
 {
     s->read_poll = enable;
-    net_socket_update_fd_handler(s);
 }
 
 static void net_socket_write_poll(NetSocketState *s, bool enable)
 {
     s->write_poll = enable;
-    net_socket_update_fd_handler(s);
 }
 
 static void net_socket_writable(void *opaque)
@@ -141,6 +134,59 @@ static ssize_t net_socket_receive_dgram(NetClientState *nc, const uint8_t *buf,
     return ret;
 }
 
+static gushort socket_connecting_readable(void *opaque)
+{
+    return G_IO_IN;
+}
+
+static gushort socket_listen_readable(void *opaque)
+{
+    /* listen only handle in-req, no err */
+    return G_IO_IN;
+}
+
+static gushort socket_establish_readable(void *opaque)
+{
+    NetSocketState *s = opaque;
+
+    /* rely on net_socket_send to handle err */
+    if (s->read_poll && net_socket_can_send(s)) {
+        return G_IO_IN|G_IO_HUP|G_IO_ERR;
+    }
+    return G_IO_HUP|G_IO_ERR;
+}
+
+static gushort socket_establish_writable(void *opaque)
+{
+    NetSocketState *s = opaque;
+
+    if (s->write_poll) {
+        return G_IO_OUT;
+    }
+    return 0;
+}
+
+static gushort socket_dgram_readable(void *opaque)
+{
+    NetSocketState *s = opaque;
+
+    /* rely on net_socket_send_dgram to handle err */
+    if (s->read_poll && net_socket_can_send(s)) {
+        return G_IO_IN|G_IO_ERR;
+    }
+    return G_IO_ERR;
+}
+
+static gushort socket_dgram_writable(void *opaque)
+{
+    NetSocketState *s = opaque;
+
+    if (s->write_poll) {
+        return G_IO_OUT;
+    }
+    return 0;
+}
+
 static void net_socket_send(void *opaque)
 {
     NetSocketState *s = opaque;
@@ -160,7 +206,11 @@ static void net_socket_send(void *opaque)
         net_socket_read_poll(s, false);
         net_socket_write_poll(s, false);
         if (s->listen_fd != -1) {
-            qemu_set_fd_handler(s->listen_fd, net_socket_accept, NULL, s);
+            event_source_release(s->nsrc);
+            s->nsrc = event_source_new(s->listen_fd, net_socket_listen_handler,
+                                s);
+            s->nsrc->readable = socket_listen_readable;
+            s->nc.info->bind_ctx(&s->nc, NULL);
         }
         closesocket(s->fd);
 
@@ -231,6 +281,8 @@ static void net_socket_send_dgram(void *opaque)
         /* end of connection */
         net_socket_read_poll(s, false);
         net_socket_write_poll(s, false);
+        /* for dgram err, removing it */
+        g_source_remove_poll(&s->nsrc->source, &s->nsrc->gfd);
         return;
     }
     qemu_send_packet(&s->nc, s->buf, size);
@@ -331,6 +383,14 @@ static void net_socket_cleanup(NetClientState *nc)
         closesocket(s->listen_fd);
         s->listen_fd = -1;
     }
+    event_source_release(s->nsrc);
+}
+
+static void net_socket_bind_ctx(NetClientState *nc, GMainContext *ctx)
+{
+    NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);
+
+    g_source_attach(&s->nsrc->source, ctx);
 }
 
 static NetClientInfo net_dgram_socket_info = {
@@ -338,8 +398,23 @@ static NetClientInfo net_dgram_socket_info = {
     .size = sizeof(NetSocketState),
     .receive = net_socket_receive_dgram,
     .cleanup = net_socket_cleanup,
+    .bind_ctx = net_socket_bind_ctx,
 };
 
+static gboolean net_socket_dgram_handler(gpointer data)
+{
+    EventGSource *nsrc = (EventGSource *)data;
+    NetSocketState *s = nsrc->opaque;
+
+    /* for err, unregister the handler */
+    if (nsrc->gfd.revents & (G_IO_IN|G_IO_ERR)) {
+        net_socket_send_dgram(s);
+    } else {
+        net_socket_writable(s);
+    }
+    return true;
+}
+
 static NetSocketState *net_socket_fd_init_dgram(NetClientState *peer,
                                                 const char *model,
                                                 const char *name,
@@ -393,8 +468,12 @@ static NetSocketState *net_socket_fd_init_dgram(NetClientState *peer,
 
     s->fd = fd;
     s->listen_fd = -1;
-    s->send_fn = net_socket_send_dgram;
+    s->nsrc = event_source_new(fd, net_socket_dgram_handler, s);
+    s->nsrc->readable = socket_dgram_readable;
+    s->nsrc->writable = socket_dgram_writable;
+    nc->info->bind_ctx(nc, NULL);
     net_socket_read_poll(s, true);
+    net_socket_write_poll(s, true);
 
     /* mcast: save bound address as dst */
     if (is_connected) {
@@ -408,20 +487,30 @@ err:
     return NULL;
 }
 
-static void net_socket_connect(void *opaque)
-{
-    NetSocketState *s = opaque;
-    s->send_fn = net_socket_send;
-    net_socket_read_poll(s, true);
-}
-
 static NetClientInfo net_socket_info = {
     .type = NET_CLIENT_OPTIONS_KIND_SOCKET,
     .size = sizeof(NetSocketState),
     .receive = net_socket_receive,
     .cleanup = net_socket_cleanup,
+    .bind_ctx = net_socket_bind_ctx,
 };
 
+static gboolean net_socket_connect_handler(gpointer data)
+{
+    EventGSource *nsrc = data;
+    NetSocketState *s = nsrc->opaque;
+
+    event_source_release(s->nsrc);
+    s->nsrc = event_source_new(s->fd, net_socket_establish_handler, s);
+    s->nsrc->readable = socket_establish_readable;
+    s->nsrc->writable = socket_establish_writable;
+    s->nc.info->bind_ctx(&s->nc, NULL);
+    net_socket_read_poll(s, true);
+    net_socket_write_poll(s, true);
+
+    return true;
+}
+
 static NetSocketState *net_socket_fd_init_stream(NetClientState *peer,
                                                  const char *model,
                                                  const char *name,
@@ -440,9 +529,20 @@ static NetSocketState *net_socket_fd_init_stream(NetClientState *peer,
     s->listen_fd = -1;
 
     if (is_connected) {
-        net_socket_connect(s);
+        assert(!s->nsrc);
+        s->nsrc = event_source_new(fd, net_socket_establish_handler, s);
+        s->nsrc->readable = socket_establish_readable;
+        s->nsrc->writable = socket_establish_writable;
+        nc->info->bind_ctx(nc, NULL);
+        net_socket_read_poll(s, true);
+        net_socket_write_poll(s, true);
     } else {
-        qemu_set_fd_handler(s->fd, NULL, net_socket_connect, s);
+        assert(!s->nsrc);
+        s->nsrc = event_source_new(fd, net_socket_connect_handler, s);
+        s->nsrc->readable = socket_connecting_readable;
+        nc->info->bind_ctx(nc, NULL);
+        net_socket_read_poll(s, true);
+        net_socket_write_poll(s, false);
     }
     return s;
 }
@@ -473,30 +573,49 @@ static NetSocketState *net_socket_fd_init(NetClientState *peer,
     return NULL;
 }
 
-static void net_socket_accept(void *opaque)
+static gboolean net_socket_establish_handler(gpointer data)
 {
-    NetSocketState *s = opaque;
+    EventGSource *nsrc = (EventGSource *)data;
+    NetSocketState *s = nsrc->opaque;
+
+    /* for err case, resort to the logic in net_socket_send to recover */
+    if (nsrc->gfd.revents & (G_IO_IN | G_IO_HUP | G_IO_ERR)) {
+        net_socket_send(s);
+    }
+    if ((nsrc->gfd.revents & G_IO_OUT)) {
+        net_socket_writable(s);
+    }
+    return true;
+}
+
+static gboolean net_socket_listen_handler(gpointer data)
+{
+    EventGSource *nsrc = data;
+    NetSocketState *s = nsrc->opaque;
     struct sockaddr_in saddr;
     socklen_t len;
     int fd;
 
-    for(;;) {
-        len = sizeof(saddr);
-        fd = qemu_accept(s->listen_fd, (struct sockaddr *)&saddr, &len);
-        if (fd < 0 && errno != EINTR) {
-            return;
-        } else if (fd >= 0) {
-            qemu_set_fd_handler(s->listen_fd, NULL, NULL, NULL);
-            break;
-        }
+    len = sizeof(saddr);
+    fd = qemu_accept(s->listen_fd, (struct sockaddr *)&saddr, &len);
+    if (fd < 0 && errno != EINTR) {
+        return false;
     }
 
     s->fd = fd;
     s->nc.link_down = false;
-    net_socket_connect(s);
+    /* prevent more than one connect req */
+    event_source_release(s->nsrc);
+    s->nsrc = event_source_new(fd, net_socket_establish_handler, s);
+    s->nsrc->readable = socket_establish_readable;
+    s->nsrc->writable = socket_establish_writable;
+    s->nc.info->bind_ctx(&s->nc, NULL);
+    net_socket_read_poll(s, true);
     snprintf(s->nc.info_str, sizeof(s->nc.info_str),
              "socket: connection from %s:%d",
              inet_ntoa(saddr.sin_addr), ntohs(saddr.sin_port));
+
+    return true;
 }
 
 static int net_socket_listen_init(NetClientState *peer,
@@ -542,7 +661,10 @@ static int net_socket_listen_init(NetClientState *peer,
     s->listen_fd = fd;
     s->nc.link_down = true;
 
-    qemu_set_fd_handler(s->listen_fd, net_socket_accept, NULL, s);
+    s->nsrc = event_source_new(fd, net_socket_listen_handler, s);
+    s->nsrc->readable = socket_listen_readable;
+    nc->info->bind_ctx(nc, NULL);
+
     return 0;
 }
 
-- 
1.7.4.4