xref: /openbmc/qemu/net/can/can_socketcan.c (revision 90f37362)
1 /*
2  * CAN c support to connect to the Linux host SocketCAN interfaces
3  *
4  * Copyright (c) 2013-2014 Jin Yang
5  * Copyright (c) 2014-2018 Pavel Pisa
6  *
7  * Initial development supported by Google GSoC 2013 from RTEMS project slot
8  *
9  * Permission is hereby granted, free of charge, to any person obtaining a copy
10  * of this software and associated documentation files (the "Software"), to deal
11  * in the Software without restriction, including without limitation the rights
12  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
13  * copies of the Software, and to permit persons to whom the Software is
14  * furnished to do so, subject to the following conditions:
15  *
16  * The above copyright notice and this permission notice shall be included in
17  * all copies or substantial portions of the Software.
18  *
19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
20  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
21  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
22  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
23  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
24  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
25  * THE SOFTWARE.
26  */
27 
28 #include "qemu/osdep.h"
29 #include "qemu/log.h"
30 #include "qemu/main-loop.h"
31 #include "qemu/module.h"
32 #include "qapi/error.h"
33 #include "chardev/char.h"
34 #include "qemu/sockets.h"
35 #include "qemu/error-report.h"
36 #include "net/can_emu.h"
37 #include "net/can_host.h"
38 
39 #include <sys/ioctl.h>
40 #include <net/if.h>
41 #include <linux/can.h>
42 #include <linux/can/raw.h>
43 #include "qom/object.h"
44 
45 #ifndef DEBUG_CAN
46 #define DEBUG_CAN 0
47 #endif /*DEBUG_CAN*/
48 
49 #define TYPE_CAN_HOST_SOCKETCAN "can-host-socketcan"
50 OBJECT_DECLARE_SIMPLE_TYPE(CanHostSocketCAN, CAN_HOST_SOCKETCAN)
51 
52 #define CAN_READ_BUF_LEN  5
53 struct CanHostSocketCAN {
54     CanHostState       parent;
55     char               *ifname;
56 
57     qemu_can_filter    *rfilter;
58     int                rfilter_num;
59     can_err_mask_t     err_mask;
60 
61     qemu_can_frame     buf[CAN_READ_BUF_LEN];
62     int                bufcnt;
63     int                bufptr;
64 
65     int                fd;
66 };
67 
68 /* Check that QEMU and Linux kernel flags encoding and structure matches */
69 QEMU_BUILD_BUG_ON(QEMU_CAN_EFF_FLAG != CAN_EFF_FLAG);
70 QEMU_BUILD_BUG_ON(QEMU_CAN_RTR_FLAG != CAN_RTR_FLAG);
71 QEMU_BUILD_BUG_ON(QEMU_CAN_ERR_FLAG != CAN_ERR_FLAG);
72 QEMU_BUILD_BUG_ON(QEMU_CAN_INV_FILTER != CAN_INV_FILTER);
73 QEMU_BUILD_BUG_ON(offsetof(qemu_can_frame, data)
74                   != offsetof(struct can_frame, data));
75 
can_host_socketcan_display_msg(struct qemu_can_frame * msg)76 static void can_host_socketcan_display_msg(struct qemu_can_frame *msg)
77 {
78     int i;
79     FILE *logfile = qemu_log_trylock();
80 
81     if (logfile) {
82         fprintf(logfile, "[cansocketcan]: %03X [%01d] %s %s",
83                 msg->can_id & QEMU_CAN_EFF_MASK,
84                 msg->can_dlc,
85                 msg->can_id & QEMU_CAN_EFF_FLAG ? "EFF" : "SFF",
86                 msg->can_id & QEMU_CAN_RTR_FLAG ? "RTR" : "DAT");
87 
88         for (i = 0; i < msg->can_dlc; i++) {
89             fprintf(logfile, " %02X", msg->data[i]);
90         }
91         fprintf(logfile, "\n");
92         qemu_log_unlock(logfile);
93     }
94 }
95 
can_host_socketcan_read(void * opaque)96 static void can_host_socketcan_read(void *opaque)
97 {
98     CanHostSocketCAN *c = opaque;
99     CanHostState *ch = CAN_HOST(c);
100 
101     /* CAN_READ_BUF_LEN for multiple messages syscall is possible for future */
102     c->bufcnt = read(c->fd, c->buf, sizeof(qemu_can_frame));
103     if (c->bufcnt < 0) {
104         warn_report("CAN bus host read failed (%s)", strerror(errno));
105         return;
106     }
107 
108     if (!ch->bus_client.fd_mode) {
109         c->buf[0].flags = 0;
110     } else {
111         if (c->bufcnt > CAN_MTU) {
112             c->buf[0].flags |= QEMU_CAN_FRMF_TYPE_FD;
113         }
114     }
115 
116     can_bus_client_send(&ch->bus_client, c->buf, 1);
117 
118     if (DEBUG_CAN) {
119         can_host_socketcan_display_msg(c->buf);
120     }
121 }
122 
can_host_socketcan_can_receive(CanBusClientState * client)123 static bool can_host_socketcan_can_receive(CanBusClientState *client)
124 {
125     return true;
126 }
127 
can_host_socketcan_receive(CanBusClientState * client,const qemu_can_frame * frames,size_t frames_cnt)128 static ssize_t can_host_socketcan_receive(CanBusClientState *client,
129                             const qemu_can_frame *frames, size_t frames_cnt)
130 {
131     CanHostState *ch = container_of(client, CanHostState, bus_client);
132     CanHostSocketCAN *c = CAN_HOST_SOCKETCAN(ch);
133 
134     size_t len;
135     int res;
136 
137     if (c->fd < 0) {
138         return -1;
139     }
140     if (frames->flags & QEMU_CAN_FRMF_TYPE_FD) {
141         if (!ch->bus_client.fd_mode) {
142             return 0;
143         }
144         len = CANFD_MTU;
145     } else {
146         len = CAN_MTU;
147 
148     }
149 
150     res = write(c->fd, frames, len);
151 
152     if (!res) {
153         warn_report("[cansocketcan]: write message to host returns zero");
154         return -1;
155     }
156 
157     if (res != len) {
158         if (res < 0) {
159             warn_report("[cansocketcan]: write to host failed (%s)",
160                         strerror(errno));
161         } else {
162             warn_report("[cansocketcan]: write to host truncated");
163         }
164         return -1;
165     }
166 
167     return 1;
168 }
169 
can_host_socketcan_disconnect(CanHostState * ch)170 static void can_host_socketcan_disconnect(CanHostState *ch)
171 {
172     CanHostSocketCAN *c = CAN_HOST_SOCKETCAN(ch);
173 
174     if (c->fd >= 0) {
175         qemu_set_fd_handler(c->fd, NULL, NULL, c);
176         close(c->fd);
177         c->fd = -1;
178     }
179 
180     g_free(c->rfilter);
181     c->rfilter = NULL;
182     c->rfilter_num = 0;
183 }
184 
185 static CanBusClientInfo can_host_socketcan_bus_client_info = {
186     .can_receive = can_host_socketcan_can_receive,
187     .receive = can_host_socketcan_receive,
188 };
189 
can_host_socketcan_connect(CanHostState * ch,Error ** errp)190 static void can_host_socketcan_connect(CanHostState *ch, Error **errp)
191 {
192     CanHostSocketCAN *c = CAN_HOST_SOCKETCAN(ch);
193     int s; /* can raw socket */
194     int mtu;
195     int enable_canfd = 1;
196     struct sockaddr_can addr;
197     struct ifreq ifr;
198 
199     if (!c->ifname) {
200         error_setg(errp, "'if' property not set");
201         return;
202     }
203 
204     /* open socket */
205     s = qemu_socket(PF_CAN, SOCK_RAW, CAN_RAW);
206     if (s < 0) {
207         error_setg_errno(errp, errno, "failed to create CAN_RAW socket");
208         return;
209     }
210 
211     addr.can_family = AF_CAN;
212     memset(&ifr.ifr_name, 0, sizeof(ifr.ifr_name));
213     strcpy(ifr.ifr_name, c->ifname);
214     /* check if the frame fits into the CAN netdevice */
215     if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
216         error_setg_errno(errp, errno,
217                          "SocketCAN host interface %s not available",
218                          c->ifname);
219         goto fail;
220     }
221     addr.can_ifindex = ifr.ifr_ifindex;
222 
223     if (ioctl(s, SIOCGIFMTU, &ifr) < 0) {
224         error_setg_errno(errp, errno,
225                          "SocketCAN host interface %s SIOCGIFMTU failed",
226                          c->ifname);
227         goto fail;
228     }
229     mtu = ifr.ifr_mtu;
230 
231     if (mtu >= CANFD_MTU) {
232         /* interface is ok - try to switch the socket into CAN FD mode */
233         if (setsockopt(s, SOL_CAN_RAW, CAN_RAW_FD_FRAMES,
234                         &enable_canfd, sizeof(enable_canfd))) {
235             warn_report("SocketCAN host interface %s enabling CAN FD failed",
236                         c->ifname);
237         } else {
238             c->parent.bus_client.fd_mode = true;
239         }
240     }
241 
242     c->err_mask = 0xffffffff; /* Receive error frame. */
243     setsockopt(s, SOL_CAN_RAW, CAN_RAW_ERR_FILTER,
244                    &c->err_mask, sizeof(c->err_mask));
245 
246     c->rfilter_num = 1;
247     c->rfilter = g_new(struct qemu_can_filter, c->rfilter_num);
248 
249     /* Receive all data frame. If |= CAN_INV_FILTER no data. */
250     c->rfilter[0].can_id = 0;
251     c->rfilter[0].can_mask = 0;
252     c->rfilter[0].can_mask &= ~CAN_ERR_FLAG;
253 
254     setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, c->rfilter,
255                c->rfilter_num * sizeof(struct qemu_can_filter));
256 
257     if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
258         error_setg_errno(errp, errno, "failed to bind to host interface %s",
259                          c->ifname);
260         goto fail;
261     }
262 
263     c->fd = s;
264     ch->bus_client.info = &can_host_socketcan_bus_client_info;
265     qemu_set_fd_handler(c->fd, can_host_socketcan_read, NULL, c);
266     return;
267 
268 fail:
269     close(s);
270     g_free(c->rfilter);
271     c->rfilter = NULL;
272     c->rfilter_num = 0;
273 }
274 
can_host_socketcan_get_if(Object * obj,Error ** errp)275 static char *can_host_socketcan_get_if(Object *obj, Error **errp)
276 {
277     CanHostSocketCAN *c = CAN_HOST_SOCKETCAN(obj);
278 
279     return g_strdup(c->ifname);
280 }
281 
can_host_socketcan_set_if(Object * obj,const char * value,Error ** errp)282 static void can_host_socketcan_set_if(Object *obj, const char *value,
283                                       Error **errp)
284 {
285     CanHostSocketCAN *c = CAN_HOST_SOCKETCAN(obj);
286     struct ifreq ifr;
287 
288     if (strlen(value) >= sizeof(ifr.ifr_name)) {
289         error_setg(errp, "CAN interface name longer than %zd characters",
290                    sizeof(ifr.ifr_name) - 1);
291         return;
292     }
293 
294     if (c->fd != -1) {
295         error_setg(errp, "CAN interface already connected");
296         return;
297     }
298 
299     g_free(c->ifname);
300     c->ifname = g_strdup(value);
301 }
302 
can_host_socketcan_instance_init(Object * obj)303 static void can_host_socketcan_instance_init(Object *obj)
304 {
305     CanHostSocketCAN *c = CAN_HOST_SOCKETCAN(obj);
306 
307     c->fd = -1;
308 }
309 
can_host_socketcan_class_init(ObjectClass * klass,void * class_data G_GNUC_UNUSED)310 static void can_host_socketcan_class_init(ObjectClass *klass,
311                                           void *class_data G_GNUC_UNUSED)
312 {
313     CanHostClass *chc = CAN_HOST_CLASS(klass);
314 
315     object_class_property_add_str(klass, "if",
316                                   can_host_socketcan_get_if,
317                                   can_host_socketcan_set_if);
318     chc->connect = can_host_socketcan_connect;
319     chc->disconnect = can_host_socketcan_disconnect;
320 }
321 
322 static const TypeInfo can_host_socketcan_info = {
323     .parent = TYPE_CAN_HOST,
324     .name = TYPE_CAN_HOST_SOCKETCAN,
325     .instance_size = sizeof(CanHostSocketCAN),
326     .instance_init = can_host_socketcan_instance_init,
327     .class_init = can_host_socketcan_class_init,
328 };
329 
can_host_register_types(void)330 static void can_host_register_types(void)
331 {
332     type_register_static(&can_host_socketcan_info);
333 }
334 
335 type_init(can_host_register_types);
336