hw/xen_nic.c

   1 /*
   2  *  xen paravirt network card backend
   3  *
   4  *  (c) Gerd Hoffmann <kraxel@redhat.com>
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; under version 2 of the License.
   9  *
  10  *  This program is distributed in the hope that it will be useful,
  11  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  *  GNU General Public License for more details.
  14  *
  15  *  You should have received a copy of the GNU General Public License along
  16  *  with this program; if not, write to the Free Software Foundation, Inc.,
  17  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <stdarg.h>
  23 #include <string.h>
  24 #include <unistd.h>
  25 #include <signal.h>
  26 #include <inttypes.h>
  27 #include <fcntl.h>
  28 #include <errno.h>
  29 #include <pthread.h>
  30 #include <sys/socket.h>
  31 #include <sys/ioctl.h>
  32 #include <sys/types.h>
  33 #include <sys/stat.h>
  34 #include <sys/mman.h>
  35 #include <sys/wait.h>
  36 #include <linux/if.h>
  37 #include <linux/if_tun.h>
  38
  39 #include <xs.h>
  40 #include <xenctrl.h>
  41 #include <xen/io/xenbus.h>
  42 #include <xen/io/netif.h>
  43
  44 #include "hw.h"
  45 #include "net.h"
  46 #include "qemu-char.h"
  47 #include "xen_backend.h"
  48
  49 /* ------------------------------------------------------------- */
  50
  51 struct XenNetDev {
  52     struct XenDevice      xendev;  /* must be first */
  53     char                  *mac;
  54     int                   tx_work;
  55     int                   tx_ring_ref;
  56     int                   rx_ring_ref;
  57     struct netif_tx_sring *txs;
  58     struct netif_rx_sring *rxs;
  59     netif_tx_back_ring_t  tx_ring;
  60     netif_rx_back_ring_t  rx_ring;
  61     VLANClientState       *vs;
  62 };
  63
  64 /* ------------------------------------------------------------- */
  65
  66 static void net_tx_response(struct XenNetDev *netdev, netif_tx_request_t *txp, int8_t st)
  67 {
  68     RING_IDX i = netdev->tx_ring.rsp_prod_pvt;
  69     netif_tx_response_t *resp;
  70     int notify;
  71
  72     resp = RING_GET_RESPONSE(&netdev->tx_ring, i);
  73     resp->id     = txp->id;
  74     resp->status = st;
  75
  76 #if 0
  77     if (txp->flags & NETTXF_extra_info)
  78         RING_GET_RESPONSE(&netdev->tx_ring, ++i)->status = NETIF_RSP_NULL;
  79 #endif
  80
  81     netdev->tx_ring.rsp_prod_pvt = ++i;
  82     RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&netdev->tx_ring, notify);
  83     if (notify)
  84         xen_be_send_notify(&netdev->xendev);
  85
  86     if (i == netdev->tx_ring.req_cons) {
  87         int more_to_do;
  88         RING_FINAL_CHECK_FOR_REQUESTS(&netdev->tx_ring, more_to_do);
  89         if (more_to_do)
  90             netdev->tx_work++;
  91     }
  92 }
  93
  94 static void net_tx_error(struct XenNetDev *netdev, netif_tx_request_t *txp, RING_IDX end)
  95 {
  96 #if 0
  97     /*
  98      * Hmm, why netback fails everything in the ring?
  99      * Should we do that even when not supporting SG and TSO?
 100      */
 101     RING_IDX cons = netdev->tx_ring.req_cons;
 102
 103     do {
 104         make_tx_response(netif, txp, NETIF_RSP_ERROR);
 105         if (cons >= end)
 106             break;
 107         txp = RING_GET_REQUEST(&netdev->tx_ring, cons++);
 108     } while (1);
 109     netdev->tx_ring.req_cons = cons;
 110     netif_schedule_work(netif);
 111     netif_put(netif);
 112 #else
 113     net_tx_response(netdev, txp, NETIF_RSP_ERROR);
 114 #endif
 115 }
 116
 117 static void net_tx_packets(struct XenNetDev *netdev)
 118 {
 119     netif_tx_request_t txreq;
 120     RING_IDX rc, rp;
 121     void *page;
 122     void *tmpbuf = NULL;
 123
 124     for (;;) {
 125         rc = netdev->tx_ring.req_cons;
 126         rp = netdev->tx_ring.sring->req_prod;
 127         xen_rmb(); /* Ensure we see queued requests up to 'rp'. */
 128
 129         while ((rc != rp)) {
 130             if (RING_REQUEST_CONS_OVERFLOW(&netdev->tx_ring, rc))
 131                 break;
 132             memcpy(&txreq, RING_GET_REQUEST(&netdev->tx_ring, rc), sizeof(txreq));
 133             netdev->tx_ring.req_cons = ++rc;
 134
 135 #if 1
 136             /* should not happen in theory, we don't announce the *
 137              * feature-{sg,gso,whatelse} flags in xenstore (yet?) */
 138             if (txreq.flags & NETTXF_extra_info) {
 139                 xen_be_printf(&netdev->xendev, 0, "FIXME: extra info flag\n");
 140                 net_tx_error(netdev, &txreq, rc);
 141                 continue;
 142             }
 143             if (txreq.flags & NETTXF_more_data) {
 144                 xen_be_printf(&netdev->xendev, 0, "FIXME: more data flag\n");
 145                 net_tx_error(netdev, &txreq, rc);
 146                 continue;
 147             }
 148 #endif
 149
 150             if (txreq.size < 14) {
 151                 xen_be_printf(&netdev->xendev, 0, "bad packet size: %d\n", txreq.size);
 152                 net_tx_error(netdev, &txreq, rc);
 153                 continue;
 154             }
 155
 156             if ((txreq.offset + txreq.size) > XC_PAGE_SIZE) {
 157                 xen_be_printf(&netdev->xendev, 0, "error: page crossing\n");
 158                 net_tx_error(netdev, &txreq, rc);
 159                 continue;
 160             }
 161
 162             xen_be_printf(&netdev->xendev, 3, "tx packet ref %d, off %d, len %d, flags 0x%x%s%s%s%s\n",
 163                           txreq.gref, txreq.offset, txreq.size, txreq.flags,
 164                           (txreq.flags & NETTXF_csum_blank)     ? " csum_blank"     : "",
 165                           (txreq.flags & NETTXF_data_validated) ? " data_validated" : "",
 166                           (txreq.flags & NETTXF_more_data)      ? " more_data"      : "",
 167                           (txreq.flags & NETTXF_extra_info)     ? " extra_info"     : "");
 168
 169             page = xc_gnttab_map_grant_ref(netdev->xendev.gnttabdev,
 170                                            netdev->xendev.dom,
 171                                            txreq.gref, PROT_READ);
 172             if (page == NULL) {
 173                 xen_be_printf(&netdev->xendev, 0, "error: tx gref dereference failed (%d)\n",
 174                               txreq.gref);
 175                 net_tx_error(netdev, &txreq, rc);
 176                 continue;
 177             }
 178             if (txreq.flags & NETTXF_csum_blank) {
 179                 /* have read-only mapping -> can't fill checksum in-place */
 180                 if (!tmpbuf)
 181                     tmpbuf = malloc(PAGE_SIZE);
 182                 memcpy(tmpbuf, page + txreq.offset, txreq.size);
 183                 net_checksum_calculate(tmpbuf, txreq.size);
 184                 qemu_send_packet(netdev->vs, tmpbuf, txreq.size);
 185             } else {
 186                 qemu_send_packet(netdev->vs, page + txreq.offset, txreq.size);
 187             }
 188             xc_gnttab_munmap(netdev->xendev.gnttabdev, page, 1);
 189             net_tx_response(netdev, &txreq, NETIF_RSP_OKAY);
 190         }
 191         if (!netdev->tx_work)
 192             break;
 193         netdev->tx_work = 0;
 194     }
 195     free(tmpbuf);
 196 }
 197
 198 /* ------------------------------------------------------------- */
 199
 200 static void net_rx_response(struct XenNetDev *netdev,
 201                             netif_rx_request_t *req, int8_t st,
 202                             uint16_t offset, uint16_t size,
 203                             uint16_t flags)
 204 {
 205     RING_IDX i = netdev->rx_ring.rsp_prod_pvt;
 206     netif_rx_response_t *resp;
 207     int notify;
 208
 209     resp = RING_GET_RESPONSE(&netdev->rx_ring, i);
 210     resp->offset     = offset;
 211     resp->flags      = flags;
 212     resp->id         = req->id;
 213     resp->status     = (int16_t)size;
 214     if (st < 0)
 215         resp->status = (int16_t)st;
 216
 217     xen_be_printf(&netdev->xendev, 3, "rx response: idx %d, status %d, flags 0x%x\n",
 218                   i, resp->status, resp->flags);
 219
 220     netdev->rx_ring.rsp_prod_pvt = ++i;
 221     RING_PUSH_RESPONSES_AND_CHECK_NOTIFY(&netdev->rx_ring, notify);
 222     if (notify)
 223         xen_be_send_notify(&netdev->xendev);
 224 }
 225
 226 #define NET_IP_ALIGN 2
 227
 228 static int net_rx_ok(void *opaque)
 229 {
 230     struct XenNetDev *netdev = opaque;
 231     RING_IDX rc, rp;
 232
 233     if (netdev->xendev.be_state != XenbusStateConnected)
 234         return 0;
 235
 236     rc = netdev->rx_ring.req_cons;
 237     rp = netdev->rx_ring.sring->req_prod;
 238     xen_rmb();
 239
 240     if (rc == rp || RING_REQUEST_CONS_OVERFLOW(&netdev->rx_ring, rc)) {
 241         xen_be_printf(&netdev->xendev, 2, "%s: no rx buffers (%d/%d)\n",
 242                       __FUNCTION__, rc, rp);
 243         return 0;
 244     }
 245     return 1;
 246 }
 247
 248 static void net_rx_packet(void *opaque, const uint8_t *buf, int size)
 249 {
 250     struct XenNetDev *netdev = opaque;
 251     netif_rx_request_t rxreq;
 252     RING_IDX rc, rp;
 253     void *page;
 254
 255     if (netdev->xendev.be_state != XenbusStateConnected)
 256         return;
 257
 258     rc = netdev->rx_ring.req_cons;
 259     rp = netdev->rx_ring.sring->req_prod;
 260     xen_rmb(); /* Ensure we see queued requests up to 'rp'. */
 261
 262     if (rc == rp || RING_REQUEST_CONS_OVERFLOW(&netdev->rx_ring, rc)) {
 263         xen_be_printf(&netdev->xendev, 2, "no buffer, drop packet\n");
 264         return;
 265     }
 266     if (size > XC_PAGE_SIZE - NET_IP_ALIGN) {
 267         xen_be_printf(&netdev->xendev, 0, "packet too big (%d > %ld)",
 268                       size, XC_PAGE_SIZE - NET_IP_ALIGN);
 269         return;
 270     }
 271
 272     memcpy(&rxreq, RING_GET_REQUEST(&netdev->rx_ring, rc), sizeof(rxreq));
 273     netdev->rx_ring.req_cons = ++rc;
 274
 275     page = xc_gnttab_map_grant_ref(netdev->xendev.gnttabdev,
 276                                    netdev->xendev.dom,
 277                                    rxreq.gref, PROT_WRITE);
 278     if (page == NULL) {
 279         xen_be_printf(&netdev->xendev, 0, "error: rx gref dereference failed (%d)\n",
 280                       rxreq.gref);
 281         net_rx_response(netdev, &rxreq, NETIF_RSP_ERROR, 0, 0, 0);
 282         return;
 283     }
 284     memcpy(page + NET_IP_ALIGN, buf, size);
 285     xc_gnttab_munmap(netdev->xendev.gnttabdev, page, 1);
 286     net_rx_response(netdev, &rxreq, NETIF_RSP_OKAY, NET_IP_ALIGN, size, 0);
 287 }
 288
 289 /* ------------------------------------------------------------- */
 290
 291 static int net_init(struct XenDevice *xendev)
 292 {
 293     struct XenNetDev *netdev = container_of(xendev, struct XenNetDev, xendev);
 294     VLANState *vlan;
 295
 296     /* read xenstore entries */
 297     if (netdev->mac == NULL)
 298         netdev->mac = xenstore_read_be_str(&netdev->xendev, "mac");
 299
 300     /* do we have all we need? */
 301     if (netdev->mac == NULL)
 302         return -1;
 303
 304     vlan = qemu_find_vlan(netdev->xendev.dev);
 305     netdev->vs = qemu_new_vlan_client(vlan, "xen", NULL,
 306                                       net_rx_packet, net_rx_ok, NULL,
 307                                       netdev);
 308     snprintf(netdev->vs->info_str, sizeof(netdev->vs->info_str),
 309              "nic: xenbus vif macaddr=%s", netdev->mac);
 310
 311     /* fill info */
 312     xenstore_write_be_int(&netdev->xendev, "feature-rx-copy", 1);
 313     xenstore_write_be_int(&netdev->xendev, "feature-rx-flip", 0);
 314
 315     return 0;
 316 }
 317
 318 static int net_connect(struct XenDevice *xendev)
 319 {
 320     struct XenNetDev *netdev = container_of(xendev, struct XenNetDev, xendev);
 321     int rx_copy;
 322
 323     if (xenstore_read_fe_int(&netdev->xendev, "tx-ring-ref",
 324                                    &netdev->tx_ring_ref) == -1)
 325         return -1;
 326     if (xenstore_read_fe_int(&netdev->xendev, "rx-ring-ref",
 327                                    &netdev->rx_ring_ref) == -1)
 328         return 1;
 329     if (xenstore_read_fe_int(&netdev->xendev, "event-channel",
 330                                    &netdev->xendev.remote_port) == -1)
 331         return -1;
 332
 333     if (xenstore_read_fe_int(&netdev->xendev, "request-rx-copy", &rx_copy) == -1)
 334         rx_copy = 0;
 335     if (rx_copy == 0) {
 336         xen_be_printf(&netdev->xendev, 0, "frontend doesn't support rx-copy.\n");
 337         return -1;
 338     }
 339
 340     netdev->txs = xc_gnttab_map_grant_ref(netdev->xendev.gnttabdev,
 341                                           netdev->xendev.dom,
 342                                           netdev->tx_ring_ref,
 343                                           PROT_READ | PROT_WRITE);
 344     netdev->rxs = xc_gnttab_map_grant_ref(netdev->xendev.gnttabdev,
 345                                           netdev->xendev.dom,
 346                                           netdev->rx_ring_ref,
 347                                           PROT_READ | PROT_WRITE);
 348     if (!netdev->txs || !netdev->rxs)
 349         return -1;
 350     BACK_RING_INIT(&netdev->tx_ring, netdev->txs, XC_PAGE_SIZE);
 351     BACK_RING_INIT(&netdev->rx_ring, netdev->rxs, XC_PAGE_SIZE);
 352
 353     xen_be_bind_evtchn(&netdev->xendev);
 354
 355     xen_be_printf(&netdev->xendev, 1, "ok: tx-ring-ref %d, rx-ring-ref %d, "
 356                   "remote port %d, local port %d\n",
 357                   netdev->tx_ring_ref, netdev->rx_ring_ref,
 358                   netdev->xendev.remote_port, netdev->xendev.local_port);
 359     return 0;
 360 }
 361
 362 static void net_disconnect(struct XenDevice *xendev)
 363 {
 364     struct XenNetDev *netdev = container_of(xendev, struct XenNetDev, xendev);
 365
 366     xen_be_unbind_evtchn(&netdev->xendev);
 367
 368     if (netdev->txs) {
 369         xc_gnttab_munmap(netdev->xendev.gnttabdev, netdev->txs, 1);
 370         netdev->txs = NULL;
 371     }
 372     if (netdev->rxs) {
 373         xc_gnttab_munmap(netdev->xendev.gnttabdev, netdev->rxs, 1);
 374         netdev->rxs = NULL;
 375     }
 376     if (netdev->vs) {
 377         qemu_del_vlan_client(netdev->vs);
 378         netdev->vs = NULL;
 379     }
 380 }
 381
 382 static void net_event(struct XenDevice *xendev)
 383 {
 384     struct XenNetDev *netdev = container_of(xendev, struct XenNetDev, xendev);
 385     net_tx_packets(netdev);
 386 }
 387
 388 static int net_free(struct XenDevice *xendev)
 389 {
 390     struct XenNetDev *netdev = container_of(xendev, struct XenNetDev, xendev);
 391
 392     qemu_free(netdev->mac);
 393     return 0;
 394 }
 395
 396 /* ------------------------------------------------------------- */
 397
 398 struct XenDevOps xen_netdev_ops = {
 399     .size       = sizeof(struct XenNetDev),
 400     .flags      = DEVOPS_FLAG_NEED_GNTDEV,
 401     .init       = net_init,
 402     .connect    = net_connect,
 403     .event      = net_event,
 404     .disconnect = net_disconnect,
 405     .free       = net_free,
 406 };