Commit 863f678f authored by Stefan Hajnoczi's avatar Stefan Hajnoczi Committed by Stefan Hajnoczi
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net: asynchronous send/receive infrastructure for net/socket.c 



The net/socket.c net client is not truly asynchronous.  This patch
borrows the qemu_set_fd_handler2() code from net/tap.c as the basis for
proper asynchronous send/receive.

Only read packets from the socket when the peer is able to receive.
This avoids needless queuing.

Later patches implement asynchronous send.

Signed-off-by: default avatarStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
parent 61518a74

net/socket.c

+52 −6
Original line number Diff line number Diff line
@@ -42,9 +42,51 @@ typedef struct NetSocketState { 
    unsigned int packet_len;

    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? */

} NetSocketState;



static void net_socket_accept(void *opaque);

static void net_socket_writable(void *opaque);



/* Only read packets from socket when peer can receive them */

static int net_socket_can_send(void *opaque)

{

    NetSocketState *s = 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)

{

    NetSocketState *s = opaque;



    net_socket_write_poll(s, false);



    qemu_flush_queued_packets(&s->nc);

}



/* XXX: we consider we can send the whole packet without blocking */

static ssize_t net_socket_receive(NetClientState *nc, const uint8_t *buf, size_t size)
@@ -81,7 +123,8 @@ static void net_socket_send(void *opaque) 
    } else if (size == 0) {

        /* end of connection */

    eoc:

        qemu_set_fd_handler(s->fd, NULL, NULL, NULL);

        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);

        }
@@ -152,7 +195,8 @@ static void net_socket_send_dgram(void *opaque) 
        return;

    if (size == 0) {

        /* end of connection */

        qemu_set_fd_handler(s->fd, NULL, NULL, NULL);

        net_socket_read_poll(s, false);

        net_socket_write_poll(s, false);

        return;

    }

    qemu_send_packet(&s->nc, s->buf, size);
@@ -243,7 +287,8 @@ static void net_socket_cleanup(NetClientState *nc) 
{

    NetSocketState *s = DO_UPCAST(NetSocketState, nc, nc);

    if (s->fd != -1) {

        qemu_set_fd_handler(s->fd, NULL, NULL, NULL);

        net_socket_read_poll(s, false);

        net_socket_write_poll(s, false);

        close(s->fd);

        s->fd = -1;

    }
@@ -314,8 +359,8 @@ static NetSocketState *net_socket_fd_init_dgram(NetClientState *peer, 


    s->fd = fd;

    s->listen_fd = -1;



    qemu_set_fd_handler(s->fd, net_socket_send_dgram, NULL, s);

    s->send_fn = net_socket_send_dgram;

    net_socket_read_poll(s, true);



    /* mcast: save bound address as dst */

    if (is_connected) {
@@ -332,7 +377,8 @@ err: 
static void net_socket_connect(void *opaque)

{

    NetSocketState *s = opaque;

    qemu_set_fd_handler(s->fd, net_socket_send, NULL, s);

    s->send_fn = net_socket_send;

    net_socket_read_poll(s, true);

}



static NetClientInfo net_socket_info = {