Archipelago » qemu

/*

 *  xen paravirt network card backend

 *

 *  (c) Gerd Hoffmann <kraxel@redhat.com>

 *

 *  This program is free software; you can redistribute it and/or modify

 *  it under the terms of the GNU General Public License as published by

 *  the Free Software Foundation; under version 2 of the License.

 *

 *  This program is distributed in the hope that it will be useful,

 *  but WITHOUT ANY WARRANTY; without even the implied warranty of

 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *  GNU General Public License for more details.

 *

 *  You should have received a copy of the GNU General Public License along

 *  with this program; if not, see <http://www.gnu.org/licenses/>.

 *

 *  Contributions after 2012-01-13 are licensed under the terms of the

 *  GNU GPL, version 2 or (at your option) any later version.

 */

#include <stdio.h>

#include <stdlib.h>

#include <stdarg.h>

#include <string.h>

#include <unistd.h>

#include <signal.h>

#include <inttypes.h>

#include <fcntl.h>

#include <errno.h>

#include <sys/socket.h>

#include <sys/ioctl.h>

#include <sys/types.h>

#include <sys/stat.h>

#include <sys/mman.h>

#include <sys/wait.h>

#include "hw.h"

#include "net/net.h"

#include "net/checksum.h"

#include "net/util.h"

#include "xen_backend.h"

#include <xen/io/netif.h>

/* ------------------------------------------------------------- */

struct XenNetDev {

    struct XenDevice      xendev;  /* must be first */

    char                  *mac;

    int                   tx_work;

    int                   tx_ring_ref;

    int                   rx_ring_ref;

    struct netif_tx_sring *txs;

    struct netif_rx_sring *rxs;

    netif_tx_back_ring_t  tx_ring;

    netif_rx_back_ring_t  rx_ring;

    NICConf               conf;

    NICState              *nic;

};

/* ------------------------------------------------------------- */

static void net_tx_response(struct XenNetDev *netdev, netif_tx_request_t *txp, int8_t st)

{

    RING_IDX i = netdev->tx_ring.rsp_prod_pvt;

    netif_tx_response_t *resp;

    int notify;

    resp = RING_GET_RESPONSE(&netdev->tx_ring, i);

    resp->id     = txp->id;

    resp->status = st;

#if 0

    if (txp->flags & NETTXF_extra_info) {

        RING_GET_RESPONSE(&netdev->tx_ring, ++i)->status = NETIF_RSP_NULL;

    }

#endif

    netdev->tx_ring.rsp_prod_pvt = ++i;

    RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&netdev->tx_ring, notify);

    if (notify) {

        xen_be_send_notify(&netdev->xendev);

    }

    if (i == netdev->tx_ring.req_cons) {

        int more_to_do;

        RING_FINAL_CHECK_FOR_REQUESTS(&netdev->tx_ring, more_to_do);

        if (more_to_do) {

            netdev->tx_work++;

        }

    }

}

static void net_tx_error(struct XenNetDev *netdev, netif_tx_request_t *txp, RING_IDX end)

{

#if 0

    /*

     * Hmm, why netback fails everything in the ring?

     * Should we do that even when not supporting SG and TSO?

     */

    RING_IDX cons = netdev->tx_ring.req_cons;

    do {

        make_tx_response(netif, txp, NETIF_RSP_ERROR);

        if (cons >= end) {

            break;

        }

        txp = RING_GET_REQUEST(&netdev->tx_ring, cons++);

    } while (1);

    netdev->tx_ring.req_cons = cons;

    netif_schedule_work(netif);

    netif_put(netif);

#else

    net_tx_response(netdev, txp, NETIF_RSP_ERROR);

#endif

}

static void net_tx_packets(struct XenNetDev *netdev)

{

    netif_tx_request_t txreq;

    RING_IDX rc, rp;

    void *page;

    void *tmpbuf = NULL;

    for (;;) {

        rc = netdev->tx_ring.req_cons;

        rp = netdev->tx_ring.sring->req_prod;

        xen_rmb(); /* Ensure we see queued requests up to 'rp'. */

        while ((rc != rp)) {

            if (RING_REQUEST_CONS_OVERFLOW(&netdev->tx_ring, rc)) {

                break;

            }

            memcpy(&txreq, RING_GET_REQUEST(&netdev->tx_ring, rc), sizeof(txreq));

            netdev->tx_ring.req_cons = ++rc;

#if 1

            /* should not happen in theory, we don't announce the *

             * feature-{sg,gso,whatelse} flags in xenstore (yet?) */

            if (txreq.flags & NETTXF_extra_info) {

                xen_be_printf(&netdev->xendev, 0, "FIXME: extra info flag\n");

                net_tx_error(netdev, &txreq, rc);

                continue;

            }

            if (txreq.flags & NETTXF_more_data) {

                xen_be_printf(&netdev->xendev, 0, "FIXME: more data flag\n");

                net_tx_error(netdev, &txreq, rc);

                continue;

            }

#endif

            if (txreq.size < 14) {

                xen_be_printf(&netdev->xendev, 0, "bad packet size: %d\n", txreq.size);

                net_tx_error(netdev, &txreq, rc);

                continue;

            }

            if ((txreq.offset + txreq.size) > XC_PAGE_SIZE) {

                xen_be_printf(&netdev->xendev, 0, "error: page crossing\n");

                net_tx_error(netdev, &txreq, rc);

                continue;

            }

            xen_be_printf(&netdev->xendev, 3, "tx packet ref %d, off %d, len %d, flags 0x%x%s%s%s%s\n",

                          txreq.gref, txreq.offset, txreq.size, txreq.flags,

                          (txreq.flags & NETTXF_csum_blank)     ? " csum_blank"     : "",

                          (txreq.flags & NETTXF_data_validated) ? " data_validated" : "",

                          (txreq.flags & NETTXF_more_data)      ? " more_data"      : "",

                          (txreq.flags & NETTXF_extra_info)     ? " extra_info"     : "");

            page = xc_gnttab_map_grant_ref(netdev->xendev.gnttabdev,

                                           netdev->xendev.dom,

                                           txreq.gref, PROT_READ);

            if (page == NULL) {

                xen_be_printf(&netdev->xendev, 0, "error: tx gref dereference failed (%d)\n",

                              txreq.gref);

                net_tx_error(netdev, &txreq, rc);

                continue;

            }

            if (txreq.flags & NETTXF_csum_blank) {

                /* have read-only mapping -> can't fill checksum in-place */

                if (!tmpbuf) {

                    tmpbuf = g_malloc(XC_PAGE_SIZE);

                }

                memcpy(tmpbuf, page + txreq.offset, txreq.size);

                net_checksum_calculate(tmpbuf, txreq.size);

                qemu_send_packet(qemu_get_queue(netdev->nic), tmpbuf,

                                 txreq.size);

            } else {

                qemu_send_packet(qemu_get_queue(netdev->nic),

                                 page + txreq.offset, txreq.size);

            }

            xc_gnttab_munmap(netdev->xendev.gnttabdev, page, 1);

            net_tx_response(netdev, &txreq, NETIF_RSP_OKAY);

        }

        if (!netdev->tx_work) {

            break;

        }

        netdev->tx_work = 0;

    }

    g_free(tmpbuf);

}

/* ------------------------------------------------------------- */

static void net_rx_response(struct XenNetDev *netdev,

                            netif_rx_request_t *req, int8_t st,

                            uint16_t offset, uint16_t size,

                            uint16_t flags)

{

    RING_IDX i = netdev->rx_ring.rsp_prod_pvt;

    netif_rx_response_t *resp;

    int notify;

    resp = RING_GET_RESPONSE(&netdev->rx_ring, i);

    resp->offset     = offset;

    resp->flags      = flags;

    resp->id         = req->id;

    resp->status     = (int16_t)size;

    if (st < 0) {

        resp->status = (int16_t)st;

    }

    xen_be_printf(&netdev->xendev, 3, "rx response: idx %d, status %d, flags 0x%x\n",

                  i, resp->status, resp->flags);

    netdev->rx_ring.rsp_prod_pvt = ++i;

    RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&netdev->rx_ring, notify);

    if (notify) {

        xen_be_send_notify(&netdev->xendev);

    }

}

#define NET_IP_ALIGN 2

static int net_rx_ok(NetClientState *nc)

{

    struct XenNetDev *netdev = qemu_get_nic_opaque(nc);

    RING_IDX rc, rp;

    if (netdev->xendev.be_state != XenbusStateConnected) {

        return 0;

    }

    rc = netdev->rx_ring.req_cons;

    rp = netdev->rx_ring.sring->req_prod;

    xen_rmb();

    if (rc == rp || RING_REQUEST_CONS_OVERFLOW(&netdev->rx_ring, rc)) {

        xen_be_printf(&netdev->xendev, 2, "%s: no rx buffers (%d/%d)\n",

                      __FUNCTION__, rc, rp);

        return 0;

    }

    return 1;

}

static ssize_t net_rx_packet(NetClientState *nc, const uint8_t *buf, size_t size)

{

    struct XenNetDev *netdev = qemu_get_nic_opaque(nc);

    netif_rx_request_t rxreq;

    RING_IDX rc, rp;

    void *page;

    if (netdev->xendev.be_state != XenbusStateConnected) {

        return -1;

    }

    rc = netdev->rx_ring.req_cons;

    rp = netdev->rx_ring.sring->req_prod;

    xen_rmb(); /* Ensure we see queued requests up to 'rp'. */

    if (rc == rp || RING_REQUEST_CONS_OVERFLOW(&netdev->rx_ring, rc)) {

        xen_be_printf(&netdev->xendev, 2, "no buffer, drop packet\n");

        return -1;

    }

    if (size > XC_PAGE_SIZE - NET_IP_ALIGN) {

        xen_be_printf(&netdev->xendev, 0, "packet too big (%lu > %ld)",

                      (unsigned long)size, XC_PAGE_SIZE - NET_IP_ALIGN);

        return -1;

    }

    memcpy(&rxreq, RING_GET_REQUEST(&netdev->rx_ring, rc), sizeof(rxreq));

    netdev->rx_ring.req_cons = ++rc;

    page = xc_gnttab_map_grant_ref(netdev->xendev.gnttabdev,

                                   netdev->xendev.dom,

                                   rxreq.gref, PROT_WRITE);

    if (page == NULL) {

        xen_be_printf(&netdev->xendev, 0, "error: rx gref dereference failed (%d)\n",

                      rxreq.gref);

        net_rx_response(netdev, &rxreq, NETIF_RSP_ERROR, 0, 0, 0);

        return -1;

    }

    memcpy(page + NET_IP_ALIGN, buf, size);

    xc_gnttab_munmap(netdev->xendev.gnttabdev, page, 1);

    net_rx_response(netdev, &rxreq, NETIF_RSP_OKAY, NET_IP_ALIGN, size, 0);

    return size;

}

/* ------------------------------------------------------------- */

static NetClientInfo net_xen_info = {

    .type = NET_CLIENT_OPTIONS_KIND_NIC,

    .size = sizeof(NICState),

    .can_receive = net_rx_ok,

    .receive = net_rx_packet,

};

static int net_init(struct XenDevice *xendev)

{

    struct XenNetDev *netdev = container_of(xendev, struct XenNetDev, xendev);

    /* read xenstore entries */

    if (netdev->mac == NULL) {

        netdev->mac = xenstore_read_be_str(&netdev->xendev, "mac");

    }

    /* do we have all we need? */

    if (netdev->mac == NULL) {

        return -1;

    }

    if (net_parse_macaddr(netdev->conf.macaddr.a, netdev->mac) < 0) {

        return -1;

    }

    netdev->nic = qemu_new_nic(&net_xen_info, &netdev->conf,

                               "xen", NULL, netdev);

    snprintf(qemu_get_queue(netdev->nic)->info_str,

             sizeof(qemu_get_queue(netdev->nic)->info_str),

             "nic: xenbus vif macaddr=%s", netdev->mac);

    /* fill info */

    xenstore_write_be_int(&netdev->xendev, "feature-rx-copy", 1);

    xenstore_write_be_int(&netdev->xendev, "feature-rx-flip", 0);

    return 0;

}

static int net_connect(struct XenDevice *xendev)

{

    struct XenNetDev *netdev = container_of(xendev, struct XenNetDev, xendev);

    int rx_copy;

    if (xenstore_read_fe_int(&netdev->xendev, "tx-ring-ref",

                             &netdev->tx_ring_ref) == -1) {

        return -1;

    }

    if (xenstore_read_fe_int(&netdev->xendev, "rx-ring-ref",

                             &netdev->rx_ring_ref) == -1) {

        return 1;

    }

    if (xenstore_read_fe_int(&netdev->xendev, "event-channel",

                             &netdev->xendev.remote_port) == -1) {

        return -1;

    }

    if (xenstore_read_fe_int(&netdev->xendev, "request-rx-copy", &rx_copy) == -1) {

        rx_copy = 0;

    }

    if (rx_copy == 0) {

        xen_be_printf(&netdev->xendev, 0, "frontend doesn't support rx-copy.\n");

        return -1;

    }

    netdev->txs = xc_gnttab_map_grant_ref(netdev->xendev.gnttabdev,

                                          netdev->xendev.dom,

                                          netdev->tx_ring_ref,

                                          PROT_READ | PROT_WRITE);

    netdev->rxs = xc_gnttab_map_grant_ref(netdev->xendev.gnttabdev,

                                          netdev->xendev.dom,

                                          netdev->rx_ring_ref,

                                          PROT_READ | PROT_WRITE);

    if (!netdev->txs || !netdev->rxs) {

        return -1;

    }

    BACK_RING_INIT(&netdev->tx_ring, netdev->txs, XC_PAGE_SIZE);

    BACK_RING_INIT(&netdev->rx_ring, netdev->rxs, XC_PAGE_SIZE);

    xen_be_bind_evtchn(&netdev->xendev);

    xen_be_printf(&netdev->xendev, 1, "ok: tx-ring-ref %d, rx-ring-ref %d, "

                  "remote port %d, local port %d\n",

                  netdev->tx_ring_ref, netdev->rx_ring_ref,

                  netdev->xendev.remote_port, netdev->xendev.local_port);

    net_tx_packets(netdev);

    return 0;

}

static void net_disconnect(struct XenDevice *xendev)

{

    struct XenNetDev *netdev = container_of(xendev, struct XenNetDev, xendev);

    xen_be_unbind_evtchn(&netdev->xendev);

    if (netdev->txs) {

        xc_gnttab_munmap(netdev->xendev.gnttabdev, netdev->txs, 1);

        netdev->txs = NULL;

    }

    if (netdev->rxs) {

        xc_gnttab_munmap(netdev->xendev.gnttabdev, netdev->rxs, 1);

        netdev->rxs = NULL;

    }

    if (netdev->nic) {

        qemu_del_nic(netdev->nic);

        netdev->nic = NULL;

    }

}

static void net_event(struct XenDevice *xendev)

{

    struct XenNetDev *netdev = container_of(xendev, struct XenNetDev, xendev);

    net_tx_packets(netdev);

    qemu_flush_queued_packets(qemu_get_queue(netdev->nic));

}

static int net_free(struct XenDevice *xendev)

{

    struct XenNetDev *netdev = container_of(xendev, struct XenNetDev, xendev);

    g_free(netdev->mac);

    return 0;

}

/* ------------------------------------------------------------- */

struct XenDevOps xen_netdev_ops = {

    .size       = sizeof(struct XenNetDev),

    .flags      = DEVOPS_FLAG_NEED_GNTDEV,

    .init       = net_init,

    .initialise    = net_connect,

    .event      = net_event,

    .disconnect = net_disconnect,

    .free       = net_free,

};