/*
 * QEMU live migration
 *
 * Copyright IBM, Corp. 2008
 *
 * Authors:
 *  Anthony Liguori   <aliguori@us.ibm.com>
 *
 * This work is licensed under the terms of the GNU GPL, version 2.  See
 * the COPYING file in the top-level directory.
 *
 */

#include "qemu-common.h"
#include "qemu/sockets.h"
#include "migration/migration.h"
#include "sysemu/char.h"
#include "sysemu/sysemu.h"
#include "buffered_file.h"
#include "block/block.h"

//#define DEBUG_MIGRATION_TCP

#ifdef DEBUG_MIGRATION_TCP
#define dprintf(fmt, ...) \
    do { printf("migration-tcp: " fmt, ## __VA_ARGS__); } while (0)
#else
#define dprintf(fmt, ...) \
    do { } while (0)
#endif

static int socket_errno(FdMigrationState *s)
{
    return errno;
}

static int socket_write(FdMigrationState *s, const void * buf, size_t size)
{
    return socket_send(s->fd, buf, size);
}

static int tcp_close(FdMigrationState *s)
{
    dprintf("tcp_close\n");
    if (s->fd != -1) {
        socket_close(s->fd);
        s->fd = -1;
    }
    return 0;
}


static void tcp_wait_for_connect(void *opaque)
{
    FdMigrationState *s = opaque;
    int ret;

    dprintf("connect completed\n");
    ret = socket_get_error(s->fd);
    if (ret < 0) {
        dprintf("error connecting %d\n", val);
        migrate_fd_error(s);
        return;
    }

    qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);

    migrate_fd_connect(s);
}

MigrationState *tcp_start_outgoing_migration(const char *host_port,
                                             int64_t bandwidth_limit,
                                             int detach)
{
    SockAddress  addr;
    FdMigrationState *s;
    int ret;

    if (parse_host_port(&addr, host_port) < 0)
        return NULL;

    s = g_malloc0(sizeof(*s));

    s->get_error = socket_errno;
    s->write = socket_write;
    s->close = tcp_close;
    s->mig_state.cancel = migrate_fd_cancel;
    s->mig_state.get_status = migrate_fd_get_status;
    s->mig_state.release = migrate_fd_release;

    s->state = MIG_STATE_ACTIVE;
    s->mon_resume = NULL;
    s->bandwidth_limit = bandwidth_limit;
    s->fd = socket_create_inet(SOCKET_STREAM);
    if (s->fd == -1) {
        g_free(s);
        return NULL;
    }

    socket_set_nonblock(s->fd);

    if (!detach)
        migrate_fd_monitor_suspend(s);

    do {
        ret = socket_connect(s->fd, &addr);
        if (ret == -1)
            ret = -(s->get_error(s));

        if (ret == -EINPROGRESS || ret == -EWOULDBLOCK || ret == -EAGAIN)
            qemu_set_fd_handler2(s->fd, NULL, NULL, tcp_wait_for_connect, s);
    } while (ret == -EINTR);

    if (ret < 0 && ret != -EINPROGRESS && ret != -EWOULDBLOCK && ret != -EAGAIN) {
        dprintf("connect failed\n");
        socket_close(s->fd);
        g_free(s);
        return NULL;
    } else if (ret >= 0)
        migrate_fd_connect(s);

    return &s->mig_state;
}

static void tcp_accept_incoming_migration(void *opaque)
{
    SockAddress  addr;
    int s = (unsigned long)opaque;
    QEMUFile *f;
    int c, ret;

    c = socket_accept(s, &addr);
    dprintf("accepted migration\n");

    if (c == -1) {
        fprintf(stderr, "could not accept migration connection\n");
        return;
    }

    f = qemu_fopen_socket(c);
    if (f == NULL) {
        fprintf(stderr, "could not qemu_fopen socket\n");
        goto out;
    }

    vm_stop(0); /* just in case */
    ret = qemu_loadvm_state(f);
    if (ret < 0) {
        fprintf(stderr, "load of migration failed\n");
        goto out_fopen;
    }
    qemu_announce_self();
    dprintf("successfully loaded vm state\n");

    /* we've successfully migrated, close the server socket */
    qemu_set_fd_handler2(s, NULL, NULL, NULL, NULL);
    socket_close(s);

    vm_start();

out_fopen:
    qemu_fclose(f);
out:
    socket_close(c);
}

int tcp_start_incoming_migration(const char *host_port)
{
    SockAddress addr;
    int s;

    if (parse_host_port(&addr, host_port) < 0) {
        fprintf(stderr, "invalid host/port combination: %s\n", host_port);
        return -EINVAL;
    }

    s = socket_create_inet(SOCKET_STREAM);
    if (s == -1)
        return -socket_error();

    socket_set_xreuseaddr(s);

    if (socket_bind(s, &addr) == -1)
        goto err;

    if (socket_listen(s, 1) == -1)
        goto err;

    qemu_set_fd_handler2(s, NULL, tcp_accept_incoming_migration, NULL,
                         (void *)(unsigned long)s);

    return 0;

err:
    socket_close(s);
    return -socket_error();
}