net/can/can_socketcan.c

   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
  44 #ifndef DEBUG_CAN
  45 #define DEBUG_CAN 0
  46 #endif /*DEBUG_CAN*/
  47
  48 #define TYPE_CAN_HOST_SOCKETCAN "can-host-socketcan"
  49 #define CAN_HOST_SOCKETCAN(obj) \
  50      OBJECT_CHECK(CanHostSocketCAN, (obj), TYPE_CAN_HOST_SOCKETCAN)
  51
  52 #define CAN_READ_BUF_LEN  5
  53 typedef 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 } CanHostSocketCAN;
  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
  76 static void can_host_socketcan_display_msg(struct qemu_can_frame *msg)
  77 {
  78     int i;
  79     FILE *logfile = qemu_log_lock();
  80     qemu_log("[cansocketcan]: %03X [%01d] %s %s",
  81              msg->can_id & QEMU_CAN_EFF_MASK,
  82              msg->can_dlc,
  83              msg->can_id & QEMU_CAN_EFF_FLAG ? "EFF" : "SFF",
  84              msg->can_id & QEMU_CAN_RTR_FLAG ? "RTR" : "DAT");
  85
  86     for (i = 0; i < msg->can_dlc; i++) {
  87         qemu_log(" %02X", msg->data[i]);
  88     }
  89     qemu_log("\n");
  90     qemu_log_flush();
  91     qemu_log_unlock(logfile);
  92 }
  93
  94 static void can_host_socketcan_read(void *opaque)
  95 {
  96     CanHostSocketCAN *c = opaque;
  97     CanHostState *ch = CAN_HOST(c);
  98
  99     /* CAN_READ_BUF_LEN for multiple messages syscall is possible for future */
 100     c->bufcnt = read(c->fd, c->buf, sizeof(qemu_can_frame));
 101     if (c->bufcnt < 0) {
 102         warn_report("CAN bus host read failed (%s)", strerror(errno));
 103         return;
 104     }
 105
 106     can_bus_client_send(&ch->bus_client, c->buf, 1);
 107
 108     if (DEBUG_CAN) {
 109         can_host_socketcan_display_msg(c->buf);
 110     }
 111 }
 112
 113 static bool can_host_socketcan_can_receive(CanBusClientState *client)
 114 {
 115     return true;
 116 }
 117
 118 static ssize_t can_host_socketcan_receive(CanBusClientState *client,
 119                             const qemu_can_frame *frames, size_t frames_cnt)
 120 {
 121     CanHostState *ch = container_of(client, CanHostState, bus_client);
 122     CanHostSocketCAN *c = CAN_HOST_SOCKETCAN(ch);
 123
 124     size_t len = sizeof(qemu_can_frame);
 125     int res;
 126
 127     if (c->fd < 0) {
 128         return -1;
 129     }
 130
 131     res = write(c->fd, frames, len);
 132
 133     if (!res) {
 134         warn_report("[cansocketcan]: write message to host returns zero");
 135         return -1;
 136     }
 137
 138     if (res != len) {
 139         if (res < 0) {
 140             warn_report("[cansocketcan]: write to host failed (%s)",
 141                         strerror(errno));
 142         } else {
 143             warn_report("[cansocketcan]: write to host truncated");
 144         }
 145         return -1;
 146     }
 147
 148     return 1;
 149 }
 150
 151 static void can_host_socketcan_disconnect(CanHostState *ch)
 152 {
 153     CanHostSocketCAN *c = CAN_HOST_SOCKETCAN(ch);
 154
 155     if (c->fd >= 0) {
 156         qemu_set_fd_handler(c->fd, NULL, NULL, c);
 157         close(c->fd);
 158         c->fd = -1;
 159     }
 160
 161     g_free(c->rfilter);
 162     c->rfilter = NULL;
 163     c->rfilter_num = 0;
 164 }
 165
 166 static CanBusClientInfo can_host_socketcan_bus_client_info = {
 167     .can_receive = can_host_socketcan_can_receive,
 168     .receive = can_host_socketcan_receive,
 169 };
 170
 171 static void can_host_socketcan_connect(CanHostState *ch, Error **errp)
 172 {
 173     CanHostSocketCAN *c = CAN_HOST_SOCKETCAN(ch);
 174     int s; /* can raw socket */
 175     struct sockaddr_can addr;
 176     struct ifreq ifr;
 177
 178     /* open socket */
 179     s = qemu_socket(PF_CAN, SOCK_RAW, CAN_RAW);
 180     if (s < 0) {
 181         error_setg_errno(errp, errno, "failed to create CAN_RAW socket");
 182         return;
 183     }
 184
 185     addr.can_family = AF_CAN;
 186     memset(&ifr.ifr_name, 0, sizeof(ifr.ifr_name));
 187     strcpy(ifr.ifr_name, c->ifname);
 188     if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
 189         error_setg_errno(errp, errno,
 190                          "SocketCAN host interface %s not available", c->ifname);
 191         goto fail;
 192     }
 193     addr.can_ifindex = ifr.ifr_ifindex;
 194
 195     c->err_mask = 0xffffffff; /* Receive error frame. */
 196     setsockopt(s, SOL_CAN_RAW, CAN_RAW_ERR_FILTER,
 197                    &c->err_mask, sizeof(c->err_mask));
 198
 199     c->rfilter_num = 1;
 200     c->rfilter = g_new(struct qemu_can_filter, c->rfilter_num);
 201
 202     /* Receive all data frame. If |= CAN_INV_FILTER no data. */
 203     c->rfilter[0].can_id = 0;
 204     c->rfilter[0].can_mask = 0;
 205     c->rfilter[0].can_mask &= ~CAN_ERR_FLAG;
 206
 207     setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, c->rfilter,
 208                c->rfilter_num * sizeof(struct qemu_can_filter));
 209
 210     if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
 211         error_setg_errno(errp, errno, "failed to bind to host interface %s",
 212                          c->ifname);
 213         goto fail;
 214     }
 215
 216     c->fd = s;
 217     ch->bus_client.info = &can_host_socketcan_bus_client_info;
 218     qemu_set_fd_handler(c->fd, can_host_socketcan_read, NULL, c);
 219     return;
 220
 221 fail:
 222     close(s);
 223     g_free(c->rfilter);
 224     c->rfilter = NULL;
 225     c->rfilter_num = 0;
 226 }
 227
 228 static char *can_host_socketcan_get_if(Object *obj, Error **errp)
 229 {
 230     CanHostSocketCAN *c = CAN_HOST_SOCKETCAN(obj);
 231
 232     return g_strdup(c->ifname);
 233 }
 234
 235 static void can_host_socketcan_set_if(Object *obj, const char *value, Error **errp)
 236 {
 237     CanHostSocketCAN *c = CAN_HOST_SOCKETCAN(obj);
 238     struct ifreq ifr;
 239
 240     if (strlen(value) >= sizeof(ifr.ifr_name)) {
 241         error_setg(errp, "CAN interface name longer than %zd characters",
 242                    sizeof(ifr.ifr_name) - 1);
 243         return;
 244     }
 245
 246     if (c->fd != -1) {
 247         error_setg(errp, "CAN interface already connected");
 248         return;
 249     }
 250
 251     g_free(c->ifname);
 252     c->ifname = g_strdup(value);
 253 }
 254
 255 static void can_host_socketcan_instance_init(Object *obj)
 256 {
 257     CanHostSocketCAN *c = CAN_HOST_SOCKETCAN(obj);
 258
 259     c->fd = -1;
 260 }
 261
 262 static void can_host_socketcan_class_init(ObjectClass *klass,
 263                                           void *class_data G_GNUC_UNUSED)
 264 {
 265     CanHostClass *chc = CAN_HOST_CLASS(klass);
 266
 267     object_class_property_add_str(klass, "if",
 268                                   can_host_socketcan_get_if,
 269                                   can_host_socketcan_set_if);
 270     chc->connect = can_host_socketcan_connect;
 271     chc->disconnect = can_host_socketcan_disconnect;
 272 }
 273
 274 static const TypeInfo can_host_socketcan_info = {
 275     .parent = TYPE_CAN_HOST,
 276     .name = TYPE_CAN_HOST_SOCKETCAN,
 277     .instance_size = sizeof(CanHostSocketCAN),
 278     .instance_init = can_host_socketcan_instance_init,
 279     .class_init = can_host_socketcan_class_init,
 280 };
 281
 282 static void can_host_register_types(void)
 283 {
 284     type_register_static(&can_host_socketcan_info);
 285 }
 286
 287 type_init(can_host_register_types);