net/filter.c

   1 /*
   2  * Copyright (c) 2015 FUJITSU LIMITED
   3  * Author: Yang Hongyang <yanghy@cn.fujitsu.com>
   4  *
   5  * This work is licensed under the terms of the GNU GPL, version 2 or
   6  * later.  See the COPYING file in the top-level directory.
   7  */
   8
   9 #include "qemu/osdep.h"
  10 #include "qapi/error.h"
  11 #include "qemu-common.h"
  12 #include "qapi/qmp/qerror.h"
  13 #include "qemu/error-report.h"
  14
  15 #include "net/filter.h"
  16 #include "net/net.h"
  17 #include "net/vhost_net.h"
  18 #include "qom/object_interfaces.h"
  19 #include "qemu/iov.h"
  20
  21 static inline bool qemu_can_skip_netfilter(NetFilterState *nf)
  22 {
  23     return !nf->on;
  24 }
  25
  26 ssize_t qemu_netfilter_receive(NetFilterState *nf,
  27                                NetFilterDirection direction,
  28                                NetClientState *sender,
  29                                unsigned flags,
  30                                const struct iovec *iov,
  31                                int iovcnt,
  32                                NetPacketSent *sent_cb)
  33 {
  34     if (qemu_can_skip_netfilter(nf)) {
  35         return 0;
  36     }
  37     if (nf->direction == direction ||
  38         nf->direction == NET_FILTER_DIRECTION_ALL) {
  39         return NETFILTER_GET_CLASS(OBJECT(nf))->receive_iov(
  40                                    nf, sender, flags, iov, iovcnt, sent_cb);
  41     }
  42
  43     return 0;
  44 }
  45
  46 static NetFilterState *netfilter_next(NetFilterState *nf,
  47                                       NetFilterDirection dir)
  48 {
  49     NetFilterState *next;
  50
  51     if (dir == NET_FILTER_DIRECTION_TX) {
  52         /* forward walk through filters */
  53         next = QTAILQ_NEXT(nf, next);
  54     } else {
  55         /* reverse order */
  56         next = QTAILQ_PREV(nf, NetFilterHead, next);
  57     }
  58
  59     return next;
  60 }
  61
  62 ssize_t qemu_netfilter_pass_to_next(NetClientState *sender,
  63                                     unsigned flags,
  64                                     const struct iovec *iov,
  65                                     int iovcnt,
  66                                     void *opaque)
  67 {
  68     int ret = 0;
  69     int direction;
  70     NetFilterState *nf = opaque;
  71     NetFilterState *next = NULL;
  72
  73     if (!sender || !sender->peer) {
  74         /* no receiver, or sender been deleted, no need to pass it further */
  75         goto out;
  76     }
  77
  78     if (nf->direction == NET_FILTER_DIRECTION_ALL) {
  79         if (sender == nf->netdev) {
  80             /* This packet is sent by netdev itself */
  81             direction = NET_FILTER_DIRECTION_TX;
  82         } else {
  83             direction = NET_FILTER_DIRECTION_RX;
  84         }
  85     } else {
  86         direction = nf->direction;
  87     }
  88
  89     next = netfilter_next(nf, direction);
  90     while (next) {
  91         /*
  92          * if qemu_netfilter_pass_to_next been called, means that
  93          * the packet has been hold by filter and has already retured size
  94          * to the sender, so sent_cb shouldn't be called later, just
  95          * pass NULL to next.
  96          */
  97         ret = qemu_netfilter_receive(next, direction, sender, flags, iov,
  98                                      iovcnt, NULL);
  99         if (ret) {
 100             return ret;
 101         }
 102         next = netfilter_next(next, direction);
 103     }
 104
 105     /*
 106      * We have gone through all filters, pass it to receiver.
 107      * Do the valid check again incase sender or receiver been
 108      * deleted while we go through filters.
 109      */
 110     if (sender && sender->peer) {
 111         qemu_net_queue_send_iov(sender->peer->incoming_queue,
 112                                 sender, flags, iov, iovcnt, NULL);
 113     }
 114
 115 out:
 116     /* no receiver, or sender been deleted */
 117     return iov_size(iov, iovcnt);
 118 }
 119
 120 static char *netfilter_get_netdev_id(Object *obj, Error **errp)
 121 {
 122     NetFilterState *nf = NETFILTER(obj);
 123
 124     return g_strdup(nf->netdev_id);
 125 }
 126
 127 static void netfilter_set_netdev_id(Object *obj, const char *str, Error **errp)
 128 {
 129     NetFilterState *nf = NETFILTER(obj);
 130
 131     nf->netdev_id = g_strdup(str);
 132 }
 133
 134 static int netfilter_get_direction(Object *obj, Error **errp G_GNUC_UNUSED)
 135 {
 136     NetFilterState *nf = NETFILTER(obj);
 137     return nf->direction;
 138 }
 139
 140 static void netfilter_set_direction(Object *obj, int direction, Error **errp)
 141 {
 142     NetFilterState *nf = NETFILTER(obj);
 143     nf->direction = direction;
 144 }
 145
 146 static char *netfilter_get_status(Object *obj, Error **errp)
 147 {
 148     NetFilterState *nf = NETFILTER(obj);
 149
 150     return nf->on ? g_strdup("on") : g_strdup("off");
 151 }
 152
 153 static void netfilter_set_status(Object *obj, const char *str, Error **errp)
 154 {
 155     NetFilterState *nf = NETFILTER(obj);
 156     NetFilterClass *nfc = NETFILTER_GET_CLASS(obj);
 157
 158     if (strcmp(str, "on") && strcmp(str, "off")) {
 159         error_setg(errp, "Invalid value for netfilter status, "
 160                          "should be 'on' or 'off'");
 161         return;
 162     }
 163     if (nf->on == !strcmp(str, "on")) {
 164         return;
 165     }
 166     nf->on = !nf->on;
 167     if (nf->netdev && nfc->status_changed) {
 168         nfc->status_changed(nf, errp);
 169     }
 170 }
 171
 172 static void netfilter_init(Object *obj)
 173 {
 174     NetFilterState *nf = NETFILTER(obj);
 175
 176     nf->on = true;
 177
 178     object_property_add_str(obj, "netdev",
 179                             netfilter_get_netdev_id, netfilter_set_netdev_id,
 180                             NULL);
 181     object_property_add_enum(obj, "queue", "NetFilterDirection",
 182                              NetFilterDirection_lookup,
 183                              netfilter_get_direction, netfilter_set_direction,
 184                              NULL);
 185     object_property_add_str(obj, "status",
 186                             netfilter_get_status, netfilter_set_status,
 187                             NULL);
 188 }
 189
 190 static void netfilter_complete(UserCreatable *uc, Error **errp)
 191 {
 192     NetFilterState *nf = NETFILTER(uc);
 193     NetClientState *ncs[MAX_QUEUE_NUM];
 194     NetFilterClass *nfc = NETFILTER_GET_CLASS(uc);
 195     int queues;
 196     Error *local_err = NULL;
 197
 198     if (!nf->netdev_id) {
 199         error_setg(errp, "Parameter 'netdev' is required");
 200         return;
 201     }
 202
 203     queues = qemu_find_net_clients_except(nf->netdev_id, ncs,
 204                                           NET_CLIENT_DRIVER_NIC,
 205                                           MAX_QUEUE_NUM);
 206     if (queues < 1) {
 207         error_setg(errp, QERR_INVALID_PARAMETER_VALUE, "netdev",
 208                    "a network backend id");
 209         return;
 210     } else if (queues > 1) {
 211         error_setg(errp, "multiqueue is not supported");
 212         return;
 213     }
 214
 215     if (get_vhost_net(ncs[0])) {
 216         error_setg(errp, "Vhost is not supported");
 217         return;
 218     }
 219
 220     nf->netdev = ncs[0];
 221
 222     if (nfc->setup) {
 223         nfc->setup(nf, &local_err);
 224         if (local_err) {
 225             error_propagate(errp, local_err);
 226             return;
 227         }
 228     }
 229     QTAILQ_INSERT_TAIL(&nf->netdev->filters, nf, next);
 230 }
 231
 232 static void netfilter_finalize(Object *obj)
 233 {
 234     NetFilterState *nf = NETFILTER(obj);
 235     NetFilterClass *nfc = NETFILTER_GET_CLASS(obj);
 236
 237     if (nfc->cleanup) {
 238         nfc->cleanup(nf);
 239     }
 240
 241     if (nf->netdev && !QTAILQ_EMPTY(&nf->netdev->filters) &&
 242         nf->next.tqe_prev) {
 243         QTAILQ_REMOVE(&nf->netdev->filters, nf, next);
 244     }
 245     g_free(nf->netdev_id);
 246 }
 247
 248 static void netfilter_class_init(ObjectClass *oc, void *data)
 249 {
 250     UserCreatableClass *ucc = USER_CREATABLE_CLASS(oc);
 251
 252     ucc->complete = netfilter_complete;
 253 }
 254
 255 static const TypeInfo netfilter_info = {
 256     .name = TYPE_NETFILTER,
 257     .parent = TYPE_OBJECT,
 258     .abstract = true,
 259     .class_size = sizeof(NetFilterClass),
 260     .class_init = netfilter_class_init,
 261     .instance_size = sizeof(NetFilterState),
 262     .instance_init = netfilter_init,
 263     .instance_finalize = netfilter_finalize,
 264     .interfaces = (InterfaceInfo[]) {
 265         { TYPE_USER_CREATABLE },
 266         { }
 267     }
 268 };
 269
 270 static void register_types(void)
 271 {
 272     type_register_static(&netfilter_info);
 273 }
 274
 275 type_init(register_types);