xref: /qemu/net/hub.c (revision 49713c41) 
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 "qemu/osdep.h"
16 #include "qapi/error.h"
17 #include "monitor/monitor.h"
18 #include "net/net.h"
19 #include "clients.h"
20 #include "hub.h"
21 #include "qemu/iov.h"
22 #include "qemu/error-report.h"
23 
24 /*
25  * A hub broadcasts incoming packets to all its ports except the source port.
26  * Hubs can be used to provide independent network segments, also confusingly
27  * named the QEMU 'vlan' feature.
28  */
29 
30 typedef struct NetHub NetHub;
31 
32 typedef struct NetHubPort {
33     NetClientState nc;
34     QLIST_ENTRY(NetHubPort) next;
35     NetHub *hub;
36     int id;
37 } NetHubPort;
38 
39 struct NetHub {
40     int id;
41     QLIST_ENTRY(NetHub) next;
42     int num_ports;
43     QLIST_HEAD(, NetHubPort) ports;
44 };
45 
46 static QLIST_HEAD(, NetHub) hubs = QLIST_HEAD_INITIALIZER(&hubs);
47 
48 static ssize_t net_hub_receive(NetHub *hub, NetHubPort *source_port,
49                                const uint8_t *buf, size_t len)
50 {
51     NetHubPort *port;
52 
53     QLIST_FOREACH(port, &hub->ports, next) {
54         if (port == source_port) {
55             continue;
56         }
57 
58         qemu_send_packet(&port->nc, buf, len);
59     }
60     return len;
61 }
62 
63 static ssize_t net_hub_receive_iov(NetHub *hub, NetHubPort *source_port,
64                                    const struct iovec *iov, int iovcnt)
65 {
66     NetHubPort *port;
67     ssize_t len = iov_size(iov, iovcnt);
68 
69     QLIST_FOREACH(port, &hub->ports, next) {
70         if (port == source_port) {
71             continue;
72         }
73 
74         qemu_sendv_packet(&port->nc, iov, iovcnt);
75     }
76     return len;
77 }
78 
79 static NetHub *net_hub_new(int id)
80 {
81     NetHub *hub;
82 
83     hub = g_malloc(sizeof(*hub));
84     hub->id = id;
85     hub->num_ports = 0;
86     QLIST_INIT(&hub->ports);
87 
88     QLIST_INSERT_HEAD(&hubs, hub, next);
89 
90     return hub;
91 }
92 
93 static int net_hub_port_can_receive(NetClientState *nc)
94 {
95     NetHubPort *port;
96     NetHubPort *src_port = DO_UPCAST(NetHubPort, nc, nc);
97     NetHub *hub = src_port->hub;
98 
99     QLIST_FOREACH(port, &hub->ports, next) {
100         if (port == src_port) {
101             continue;
102         }
103 
104         if (qemu_can_send_packet(&port->nc)) {
105             return 1;
106         }
107     }
108 
109     return 0;
110 }
111 
112 static ssize_t net_hub_port_receive(NetClientState *nc,
113                                     const uint8_t *buf, size_t len)
114 {
115     NetHubPort *port = DO_UPCAST(NetHubPort, nc, nc);
116 
117     return net_hub_receive(port->hub, port, buf, len);
118 }
119 
120 static ssize_t net_hub_port_receive_iov(NetClientState *nc,
121                                         const struct iovec *iov, int iovcnt)
122 {
123     NetHubPort *port = DO_UPCAST(NetHubPort, nc, nc);
124 
125     return net_hub_receive_iov(port->hub, port, iov, iovcnt);
126 }
127 
128 static void net_hub_port_cleanup(NetClientState *nc)
129 {
130     NetHubPort *port = DO_UPCAST(NetHubPort, nc, nc);
131 
132     QLIST_REMOVE(port, next);
133 }
134 
135 static NetClientInfo net_hub_port_info = {
136     .type = NET_CLIENT_DRIVER_HUBPORT,
137     .size = sizeof(NetHubPort),
138     .can_receive = net_hub_port_can_receive,
139     .receive = net_hub_port_receive,
140     .receive_iov = net_hub_port_receive_iov,
141     .cleanup = net_hub_port_cleanup,
142 };
143 
144 static NetHubPort *net_hub_port_new(NetHub *hub, const char *name,
145                                     NetClientState *hubpeer)
146 {
147     NetClientState *nc;
148     NetHubPort *port;
149     int id = hub->num_ports++;
150     char default_name[128];
151 
152     if (!name) {
153         snprintf(default_name, sizeof(default_name),
154                  "hub%dport%d", hub->id, id);
155         name = default_name;
156     }
157 
158     nc = qemu_new_net_client(&net_hub_port_info, hubpeer, "hub", name);
159     port = DO_UPCAST(NetHubPort, nc, nc);
160     port->id = id;
161     port->hub = hub;
162 
163     QLIST_INSERT_HEAD(&hub->ports, port, next);
164 
165     return port;
166 }
167 
168 /**
169  * Create a port on a given hub
170  * @hub_id: Number of the hub
171  * @name: Net client name or NULL for default name.
172  * @hubpeer: Peer to use (if "netdev=id" has been specified)
173  *
174  * If there is no existing hub with the given id then a new hub is created.
175  */
176 NetClientState *net_hub_add_port(int hub_id, const char *name,
177                                  NetClientState *hubpeer)
178 {
179     NetHub *hub;
180     NetHubPort *port;
181 
182     QLIST_FOREACH(hub, &hubs, next) {
183         if (hub->id == hub_id) {
184             break;
185         }
186     }
187 
188     if (!hub) {
189         hub = net_hub_new(hub_id);
190     }
191 
192     port = net_hub_port_new(hub, name, hubpeer);
193     return &port->nc;
194 }
195 
196 /**
197  * Find a specific client on a hub
198  */
199 NetClientState *net_hub_find_client_by_name(int hub_id, const char *name)
200 {
201     NetHub *hub;
202     NetHubPort *port;
203     NetClientState *peer;
204 
205     QLIST_FOREACH(hub, &hubs, next) {
206         if (hub->id == hub_id) {
207             QLIST_FOREACH(port, &hub->ports, next) {
208                 peer = port->nc.peer;
209 
210                 if (peer && strcmp(peer->name, name) == 0) {
211                     return peer;
212                 }
213             }
214         }
215     }
216     return NULL;
217 }
218 
219 /**
220  * Find a available port on a hub; otherwise create one new port
221  */
222 NetClientState *net_hub_port_find(int hub_id)
223 {
224     NetHub *hub;
225     NetHubPort *port;
226     NetClientState *nc;
227 
228     QLIST_FOREACH(hub, &hubs, next) {
229         if (hub->id == hub_id) {
230             QLIST_FOREACH(port, &hub->ports, next) {
231                 nc = port->nc.peer;
232                 if (!nc) {
233                     return &(port->nc);
234                 }
235             }
236             break;
237         }
238     }
239 
240     nc = net_hub_add_port(hub_id, NULL, NULL);
241     return nc;
242 }
243 
244 /**
245  * Print hub configuration
246  */
247 void net_hub_info(Monitor *mon)
248 {
249     NetHub *hub;
250     NetHubPort *port;
251 
252     QLIST_FOREACH(hub, &hubs, next) {
253         monitor_printf(mon, "hub %d\n", hub->id);
254         QLIST_FOREACH(port, &hub->ports, next) {
255             monitor_printf(mon, " \\ %s", port->nc.name);
256             if (port->nc.peer) {
257                 monitor_printf(mon, ": ");
258                 print_net_client(mon, port->nc.peer);
259             } else {
260                 monitor_printf(mon, "\n");
261             }
262         }
263     }
264 }
265 
266 /**
267  * Get the hub id that a client is connected to
268  *
269  * @id: Pointer for hub id output, may be NULL
270  */
271 int net_hub_id_for_client(NetClientState *nc, int *id)
272 {
273     NetHubPort *port;
274 
275     if (nc->info->type == NET_CLIENT_DRIVER_HUBPORT) {
276         port = DO_UPCAST(NetHubPort, nc, nc);
277     } else if (nc->peer != NULL && nc->peer->info->type ==
278             NET_CLIENT_DRIVER_HUBPORT) {
279         port = DO_UPCAST(NetHubPort, nc, nc->peer);
280     } else {
281         return -ENOENT;
282     }
283 
284     if (id) {
285         *id = port->hub->id;
286     }
287     return 0;
288 }
289 
290 int net_init_hubport(const Netdev *netdev, const char *name,
291                      NetClientState *peer, Error **errp)
292 {
293     const NetdevHubPortOptions *hubport;
294     NetClientState *hubpeer = NULL;
295 
296     assert(netdev->type == NET_CLIENT_DRIVER_HUBPORT);
297     assert(!peer);
298     hubport = &netdev->u.hubport;
299 
300     if (hubport->has_netdev) {
301         hubpeer = qemu_find_netdev(hubport->netdev);
302         if (!hubpeer) {
303             error_setg(errp, "netdev '%s' not found", hubport->netdev);
304             return -1;
305         }
306     }
307 
308     net_hub_add_port(hubport->hubid, name, hubpeer);
309 
310     return 0;
311 }
312 
313 /**
314  * Warn if hub configurations are likely wrong
315  */
316 void net_hub_check_clients(void)
317 {
318     NetHub *hub;
319     NetHubPort *port;
320     NetClientState *peer;
321 
322     QLIST_FOREACH(hub, &hubs, next) {
323         int has_nic = 0, has_host_dev = 0;
324 
325         QLIST_FOREACH(port, &hub->ports, next) {
326             peer = port->nc.peer;
327             if (!peer) {
328                 warn_report("hub port %s has no peer", port->nc.name);
329                 continue;
330             }
331 
332             switch (peer->info->type) {
333             case NET_CLIENT_DRIVER_NIC:
334                 has_nic = 1;
335                 break;
336             case NET_CLIENT_DRIVER_USER:
337             case NET_CLIENT_DRIVER_TAP:
338             case NET_CLIENT_DRIVER_SOCKET:
339             case NET_CLIENT_DRIVER_VDE:
340             case NET_CLIENT_DRIVER_VHOST_USER:
341                 has_host_dev = 1;
342                 break;
343             default:
344                 break;
345             }
346         }
347         if (has_host_dev && !has_nic) {
348             warn_report("vlan %d with no nics", hub->id);
349         }
350         if (has_nic && !has_host_dev) {
351             warn_report("vlan %d is not connected to host network", hub->id);
352         }
353     }
354 }
355 
356 bool net_hub_flush(NetClientState *nc)
357 {
358     NetHubPort *port;
359     NetHubPort *source_port = DO_UPCAST(NetHubPort, nc, nc);
360     int ret = 0;
361 
362     QLIST_FOREACH(port, &source_port->hub->ports, next) {
363         if (port != source_port) {
364             ret += qemu_net_queue_flush(port->nc.incoming_queue);
365         }
366     }
367     return ret ? true : false;
368 }
369