net/hub.c

   1 /*
   2  * Hub net client
   3  *
   4  * Copyright IBM, Corp. 2012
   5  *
   6  * Authors:
   7  *  Stefan Hajnoczi   <stefanha@linux.vnet.ibm.com>
   8  *  Zhi Yong Wu       <wuzhy@linux.vnet.ibm.com>
   9  *
  10  * This work is licensed under the terms of the GNU LGPL, version 2 or later.
  11  * See the COPYING.LIB file in the top-level directory.
  12  *
  13  */
  14
  15 #include "monitor.h"
  16 #include "net.h"
  17 #include "hub.h"
  18 #include "iov.h"
  19
  20 /*
  21  * A hub broadcasts incoming packets to all its ports except the source port.
  22  * Hubs can be used to provide independent network segments, also confusingly
  23  * named the QEMU 'vlan' feature.
  24  */
  25
  26 typedef struct NetHub NetHub;
  27
  28 typedef struct NetHubPort {
  29     NetClientState nc;
  30     QLIST_ENTRY(NetHubPort) next;
  31     NetHub *hub;
  32     int id;
  33 } NetHubPort;
  34
  35 struct NetHub {
  36     int id;
  37     QLIST_ENTRY(NetHub) next;
  38     int num_ports;
  39     QLIST_HEAD(, NetHubPort) ports;
  40 };
  41
  42 static QLIST_HEAD(, NetHub) hubs = QLIST_HEAD_INITIALIZER(&hubs);
  43
  44 static ssize_t net_hub_receive(NetHub *hub, NetHubPort *source_port,
  45                                const uint8_t *buf, size_t len)
  46 {
  47     NetHubPort *port;
  48
  49     QLIST_FOREACH(port, &hub->ports, next) {
  50         if (port == source_port) {
  51             continue;
  52         }
  53
  54         qemu_send_packet(&port->nc, buf, len);
  55     }
  56     return len;
  57 }
  58
  59 static ssize_t net_hub_receive_iov(NetHub *hub, NetHubPort *source_port,
  60                                    const struct iovec *iov, int iovcnt)
  61 {
  62     NetHubPort *port;
  63     ssize_t len = iov_size(iov, iovcnt);
  64
  65     QLIST_FOREACH(port, &hub->ports, next) {
  66         if (port == source_port) {
  67             continue;
  68         }
  69
  70         qemu_sendv_packet(&port->nc, iov, iovcnt);
  71     }
  72     return len;
  73 }
  74
  75 static NetHub *net_hub_new(int id)
  76 {
  77     NetHub *hub;
  78
  79     hub = g_malloc(sizeof(*hub));
  80     hub->id = id;
  81     hub->num_ports = 0;
  82     QLIST_INIT(&hub->ports);
  83
  84     QLIST_INSERT_HEAD(&hubs, hub, next);
  85
  86     return hub;
  87 }
  88
  89 static int net_hub_port_can_receive(NetClientState *nc)
  90 {
  91     NetHubPort *port;
  92     NetHubPort *src_port = DO_UPCAST(NetHubPort, nc, nc);
  93     NetHub *hub = src_port->hub;
  94
  95     QLIST_FOREACH(port, &hub->ports, next) {
  96         if (port == src_port) {
  97             continue;
  98         }
  99
 100         if (qemu_can_send_packet(&port->nc)) {
 101             return 1;
 102         }
 103     }
 104
 105     return 0;
 106 }
 107
 108 static ssize_t net_hub_port_receive(NetClientState *nc,
 109                                     const uint8_t *buf, size_t len)
 110 {
 111     NetHubPort *port = DO_UPCAST(NetHubPort, nc, nc);
 112
 113     return net_hub_receive(port->hub, port, buf, len);
 114 }
 115
 116 static ssize_t net_hub_port_receive_iov(NetClientState *nc,
 117                                         const struct iovec *iov, int iovcnt)
 118 {
 119     NetHubPort *port = DO_UPCAST(NetHubPort, nc, nc);
 120
 121     return net_hub_receive_iov(port->hub, port, iov, iovcnt);
 122 }
 123
 124 static void net_hub_port_cleanup(NetClientState *nc)
 125 {
 126     NetHubPort *port = DO_UPCAST(NetHubPort, nc, nc);
 127
 128     QLIST_REMOVE(port, next);
 129 }
 130
 131 static NetClientInfo net_hub_port_info = {
 132     .type = NET_CLIENT_OPTIONS_KIND_HUBPORT,
 133     .size = sizeof(NetHubPort),
 134     .can_receive = net_hub_port_can_receive,
 135     .receive = net_hub_port_receive,
 136     .receive_iov = net_hub_port_receive_iov,
 137     .cleanup = net_hub_port_cleanup,
 138 };
 139
 140 static NetHubPort *net_hub_port_new(NetHub *hub, const char *name)
 141 {
 142     NetClientState *nc;
 143     NetHubPort *port;
 144     int id = hub->num_ports++;
 145     char default_name[128];
 146
 147     if (!name) {
 148         snprintf(default_name, sizeof(default_name),
 149                  "hub%dport%d", hub->id, id);
 150         name = default_name;
 151     }
 152
 153     nc = qemu_new_net_client(&net_hub_port_info, NULL, "hub", name);
 154     port = DO_UPCAST(NetHubPort, nc, nc);
 155     port->id = id;
 156     port->hub = hub;
 157
 158     QLIST_INSERT_HEAD(&hub->ports, port, next);
 159
 160     return port;
 161 }
 162
 163 /**
 164  * Create a port on a given hub
 165  * @name: Net client name or NULL for default name.
 166  *
 167  * If there is no existing hub with the given id then a new hub is created.
 168  */
 169 NetClientState *net_hub_add_port(int hub_id, const char *name)
 170 {
 171     NetHub *hub;
 172     NetHubPort *port;
 173
 174     QLIST_FOREACH(hub, &hubs, next) {
 175         if (hub->id == hub_id) {
 176             break;
 177         }
 178     }
 179
 180     if (!hub) {
 181         hub = net_hub_new(hub_id);
 182     }
 183
 184     port = net_hub_port_new(hub, name);
 185     return &port->nc;
 186 }
 187
 188 /**
 189  * Find a specific client on a hub
 190  */
 191 NetClientState *net_hub_find_client_by_name(int hub_id, const char *name)
 192 {
 193     NetHub *hub;
 194     NetHubPort *port;
 195     NetClientState *peer;
 196
 197     QLIST_FOREACH(hub, &hubs, next) {
 198         if (hub->id == hub_id) {
 199             QLIST_FOREACH(port, &hub->ports, next) {
 200                 peer = port->nc.peer;
 201
 202                 if (peer && strcmp(peer->name, name) == 0) {
 203                     return peer;
 204                 }
 205             }
 206         }
 207     }
 208     return NULL;
 209 }
 210
 211 /**
 212  * Find a available port on a hub; otherwise create one new port
 213  */
 214 NetClientState *net_hub_port_find(int hub_id)
 215 {
 216     NetHub *hub;
 217     NetHubPort *port;
 218     NetClientState *nc;
 219
 220     QLIST_FOREACH(hub, &hubs, next) {
 221         if (hub->id == hub_id) {
 222             QLIST_FOREACH(port, &hub->ports, next) {
 223                 nc = port->nc.peer;
 224                 if (!nc) {
 225                     return &(port->nc);
 226                 }
 227             }
 228             break;
 229         }
 230     }
 231
 232     nc = net_hub_add_port(hub_id, NULL);
 233     return nc;
 234 }
 235
 236 /**
 237  * Print hub configuration
 238  */
 239 void net_hub_info(Monitor *mon)
 240 {
 241     NetHub *hub;
 242     NetHubPort *port;
 243
 244     QLIST_FOREACH(hub, &hubs, next) {
 245         monitor_printf(mon, "hub %d\n", hub->id);
 246         QLIST_FOREACH(port, &hub->ports, next) {
 247             if (port->nc.peer) {
 248                 monitor_printf(mon, " \\ ");
 249                 print_net_client(mon, port->nc.peer);
 250             }
 251         }
 252     }
 253 }
 254
 255 /**
 256  * Get the hub id that a client is connected to
 257  *
 258  * @id              Pointer for hub id output, may be NULL
 259  */
 260 int net_hub_id_for_client(NetClientState *nc, int *id)
 261 {
 262     NetHubPort *port;
 263
 264     if (nc->info->type == NET_CLIENT_OPTIONS_KIND_HUBPORT) {
 265         port = DO_UPCAST(NetHubPort, nc, nc);
 266     } else if (nc->peer != NULL && nc->peer->info->type ==
 267             NET_CLIENT_OPTIONS_KIND_HUBPORT) {
 268         port = DO_UPCAST(NetHubPort, nc, nc->peer);
 269     } else {
 270         return -ENOENT;
 271     }
 272
 273     if (id) {
 274         *id = port->hub->id;
 275     }
 276     return 0;
 277 }
 278
 279 int net_init_hubport(const NetClientOptions *opts, const char *name,
 280                      NetClientState *peer)
 281 {
 282     const NetdevHubPortOptions *hubport;
 283
 284     assert(opts->kind == NET_CLIENT_OPTIONS_KIND_HUBPORT);
 285     hubport = opts->hubport;
 286
 287     /* Treat hub port like a backend, NIC must be the one to peer */
 288     if (peer) {
 289         return -EINVAL;
 290     }
 291
 292     net_hub_add_port(hubport->hubid, name);
 293     return 0;
 294 }
 295
 296 /**
 297  * Warn if hub configurations are likely wrong
 298  */
 299 void net_hub_check_clients(void)
 300 {
 301     NetHub *hub;
 302     NetHubPort *port;
 303     NetClientState *peer;
 304
 305     QLIST_FOREACH(hub, &hubs, next) {
 306         int has_nic = 0, has_host_dev = 0;
 307
 308         QLIST_FOREACH(port, &hub->ports, next) {
 309             peer = port->nc.peer;
 310             if (!peer) {
 311                 fprintf(stderr, "Warning: hub port %s has no peer\n",
 312                         port->nc.name);
 313                 continue;
 314             }
 315
 316             switch (peer->info->type) {
 317             case NET_CLIENT_OPTIONS_KIND_NIC:
 318                 has_nic = 1;
 319                 break;
 320             case NET_CLIENT_OPTIONS_KIND_USER:
 321             case NET_CLIENT_OPTIONS_KIND_TAP:
 322             case NET_CLIENT_OPTIONS_KIND_SOCKET:
 323             case NET_CLIENT_OPTIONS_KIND_VDE:
 324                 has_host_dev = 1;
 325                 break;
 326             default:
 327                 break;
 328             }
 329         }
 330         if (has_host_dev && !has_nic) {
 331             fprintf(stderr, "Warning: vlan %d with no nics\n", hub->id);
 332         }
 333         if (has_nic && !has_host_dev) {
 334             fprintf(stderr,
 335                     "Warning: vlan %d is not connected to host network\n",
 336                     hub->id);
 337         }
 338     }
 339 }