[Qemu-devel] [PATCH V4 2/7] CAN bus support to connect bust to Linux host SocketCAN interface.

[pisa]

From: Pavel Pisa <address@hidden>

Connection to the real host CAN bus network through
SocketCAN network interface is available only for Linux
host system. Mechanism is generic, support for another
CAN API and operating systems can be implemented in future.

Signed-off-by: Pavel Pisa <address@hidden>
---
 hw/can/Makefile.objs   |   4 +
 hw/can/can_socketcan.c | 314 +++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 318 insertions(+)
 create mode 100644 hw/can/can_socketcan.c

diff --git a/hw/can/Makefile.objs b/hw/can/Makefile.objs
index 1028d7c455..f999085f7a 100644
--- a/hw/can/Makefile.objs
+++ b/hw/can/Makefile.objs
@@ -2,5 +2,9 @@
 
 ifeq ($(CONFIG_CAN_CORE),y)
 common-obj-y += can_core.o
+ifeq ($(CONFIG_LINUX),y)
+common-obj-y += can_socketcan.o
+else
 common-obj-y += can_host_stub.o
 endif
+endif
diff --git a/hw/can/can_socketcan.c b/hw/can/can_socketcan.c
new file mode 100644
index 0000000000..f6df747c5a
--- /dev/null
+++ b/hw/can/can_socketcan.c
@@ -0,0 +1,314 @@
+/*
+ * CAN socketcan support to connect to the Linux host SocketCAN interfaces
+ *
+ * Copyright (c) 2013-2014 Jin Yang
+ * Copyright (c) 2014-2018 Pavel Pisa
+ *
+ * Initial development supported by Google GSoC 2013 from RTEMS project slot
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to 
deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 
FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "qemu/error-report.h"
+#include "chardev/char.h"
+#include "qemu/sockets.h"
+#include "qemu/error-report.h"
+#include "hw/hw.h"
+#include "can/can_emu.h"
+
+#include <sys/ioctl.h>
+#include <net/if.h>
+#include <linux/can.h>
+#include <linux/can/raw.h>
+
+#ifndef DEBUG_CAN
+#define DEBUG_CAN 0
+#endif /*DEBUG_CAN*/
+
+#define CAN_READ_BUF_LEN  5
+typedef struct {
+    CanBusClientState  bus_client;
+    qemu_can_filter    *rfilter;
+    int                rfilter_num;
+    can_err_mask_t     err_mask;
+
+    qemu_can_frame     buf[CAN_READ_BUF_LEN];
+    int                bufcnt;
+    int                bufptr;
+
+    int                fd;
+} CanBusSocketcanConnectState;
+
+static void can_bus_socketcan_display_msg(struct qemu_can_frame *msg)
+{
+    int i;
+
+    /* Check that QEMU and Linux kernel flags encoding matches */
+    assert(QEMU_CAN_EFF_FLAG == CAN_EFF_FLAG);
+    assert(QEMU_CAN_RTR_FLAG == CAN_RTR_FLAG);
+    assert(QEMU_CAN_ERR_FLAG == CAN_ERR_FLAG);
+
+    assert(QEMU_CAN_INV_FILTER == CAN_INV_FILTER);
+
+    assert(offsetof(qemu_can_frame, data) == offsetof(struct can_frame, data));
+
+    qemu_log_lock();
+    qemu_log("[cansocketcan]: %03X [%01d] %s %s",
+             msg->can_id & QEMU_CAN_EFF_MASK,
+             msg->can_dlc,
+             msg->can_id & QEMU_CAN_EFF_FLAG ? "EFF" : "SFF",
+             msg->can_id & QEMU_CAN_RTR_FLAG ? "RTR" : "DAT");
+
+    for (i = 0; i < msg->can_dlc; i++) {
+        qemu_log(" %02X", msg->data[i]);
+    }
+    qemu_log("\n");
+    qemu_log_flush();
+    qemu_log_unlock();
+}
+
+static void can_bus_socketcan_read(void *opaque)
+{
+    CanBusSocketcanConnectState *c;
+    c = (CanBusSocketcanConnectState *)opaque;
+
+
+
+    /* CAN_READ_BUF_LEN for multiple messages syscall is possible for future */
+    c->bufcnt = read(c->fd, c->buf, sizeof(qemu_can_frame));
+    if (c->bufcnt < 0) {
+        warn_report("CAN bus host read failed (%s)", strerror(errno));
+        return;
+    }
+
+    can_bus_client_send(&c->bus_client, c->buf, 1);
+
+    if (DEBUG_CAN) {
+        can_bus_socketcan_display_msg(c->buf);
+    }
+}
+
+static int can_bus_socketcan_can_receive(CanBusClientState *client)
+{
+    CanBusSocketcanConnectState *c;
+    c = container_of(client, CanBusSocketcanConnectState, bus_client);
+
+    if (c->fd < 0) {
+        return -1;
+    }
+
+    return 1;
+}
+
+static ssize_t can_bus_socketcan_receive(CanBusClientState *client,
+                            const qemu_can_frame *frames, size_t frames_cnt)
+{
+    CanBusSocketcanConnectState *c;
+    c = container_of(client, CanBusSocketcanConnectState, bus_client);
+    size_t len = sizeof(qemu_can_frame);
+    int res;
+
+    if (c->fd < 0) {
+        return -1;
+    }
+
+    res = write(c->fd, frames, len);
+
+    if (!res) {
+        warn_report("[cansocketcan]: write message to host returns zero");
+        return -1;
+    }
+
+    if (res != len) {
+        if (res < 0) {
+            warn_report("[cansocketcan]: write to host failed (%s)",
+                        strerror(errno));
+        } else {
+            warn_report("[cansocketcan]: write to host truncated");
+        }
+        return -1;
+    }
+
+    return 1;
+}
+
+static void can_bus_socketcan_cleanup(CanBusClientState *client)
+{
+    CanBusSocketcanConnectState *c;
+    c = container_of(client, CanBusSocketcanConnectState, bus_client);
+
+    if (c->fd >= 0) {
+        qemu_set_fd_handler(c->fd, NULL, NULL, c);
+        close(c->fd);
+        c->fd = -1;
+    }
+
+    c->rfilter_num = 0;
+    if (c->rfilter != NULL) {
+        g_free(c->rfilter);
+    }
+}
+
+static int can_bus_socketcan_set_filters(CanBusClientState *client,
+                   const struct qemu_can_filter *filters, size_t filters_cnt)
+{
+    CanBusSocketcanConnectState *c;
+    c = container_of(client, CanBusSocketcanConnectState, bus_client);
+
+    int i;
+
+    if (DEBUG_CAN) {
+        qemu_log_lock();
+        qemu_log("[cansocketcan]: filters set for channel\n");
+        for (i = 0; i < filters_cnt; i++) {
+            fprintf(stderr, "[%i]  id=0x%08x maks=0x%08x\n",
+                   i, filters[i].can_id, filters[i].can_mask);
+        }
+        qemu_log("\n");
+        qemu_log_flush();
+        qemu_log_unlock();
+    }
+
+    setsockopt(c->fd, SOL_CAN_RAW, CAN_RAW_FILTER,
+               filters, filters_cnt * sizeof(qemu_can_filter));
+
+    return 0;
+}
+
+static
+void can_bus_socketcan_update_read_handler(CanBusSocketcanConnectState *c)
+{
+    if (c->fd >= 0) {
+        qemu_set_fd_handler(c->fd, can_bus_socketcan_read, NULL, c);
+    }
+}
+
+static CanBusClientInfo can_bus_socketcan_bus_client_info = {
+    .can_receive = can_bus_socketcan_can_receive,
+    .receive = can_bus_socketcan_receive,
+    .cleanup = can_bus_socketcan_cleanup,
+    .poll = NULL
+};
+
+static CanBusSocketcanConnectState *
+    can_bus_socketcan_connect_new(const char *host_dev_name)
+{
+    int s; /* can raw socket */
+    CanBusSocketcanConnectState    *c;
+    struct sockaddr_can addr;
+    struct ifreq ifr;
+
+    c = g_malloc0(sizeof(CanBusSocketcanConnectState));
+    if (c == NULL) {
+        goto fail1;
+    }
+
+    c->fd = -1;
+
+    /* open socket */
+    s = socket(PF_CAN, SOCK_RAW, CAN_RAW);
+    if (s < 0) {
+        error_report("[cansocketcan]: CAN_RAW socket create failed  (%s)",
+                        strerror(errno));
+        goto fail;
+    }
+
+    addr.can_family = AF_CAN;
+    memset(&ifr.ifr_name, 0, sizeof(ifr.ifr_name));
+    strcpy(ifr.ifr_name, host_dev_name);
+    if (ioctl(s, SIOCGIFINDEX, &ifr) < 0) {
+        error_report("[cansocketcan]: host interface %s not available (%s)",
+                     host_dev_name, strerror(errno));
+        goto fail;
+    }
+    addr.can_ifindex = ifr.ifr_ifindex;
+
+    c->err_mask = 0xffffffff; /* Receive error frame. */
+    setsockopt(s, SOL_CAN_RAW, CAN_RAW_ERR_FILTER,
+                   &c->err_mask, sizeof(c->err_mask));
+
+    c->rfilter_num = 1;
+    c->rfilter = g_malloc0(c->rfilter_num * sizeof(struct qemu_can_filter));
+    if (c->rfilter == NULL) {
+        goto fail;
+    }
+
+    /* Receive all data frame. If |= CAN_INV_FILTER no data. */
+    c->rfilter[0].can_id = 0;
+    c->rfilter[0].can_mask = 0;
+    c->rfilter[0].can_mask &= ~CAN_ERR_FLAG;
+
+    setsockopt(s, SOL_CAN_RAW, CAN_RAW_FILTER, c->rfilter,
+               c->rfilter_num * sizeof(struct qemu_can_filter));
+
+    if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) < 0) {
+        error_report("[cansocketcan]: bind to host interface %s failed (%s)",
+                     host_dev_name, strerror(errno));
+        goto fail;
+    }
+
+    c->fd = s;
+
+    c->bus_client.info = &can_bus_socketcan_bus_client_info;
+
+    can_bus_socketcan_update_read_handler(c);
+
+    return c;
+
+fail:
+    can_bus_socketcan_cleanup(&c->bus_client);
+    g_free(c);
+fail1:
+
+    return NULL;
+}
+
+static int can_bus_connect_to_host_socketcan(CanBusState *bus,
+                                             const char *host_dev_name)
+{
+    CanBusSocketcanConnectState *c;
+
+    c = can_bus_socketcan_connect_new(host_dev_name);
+    if (c == NULL) {
+        error_report("CAN bus setup of host connect to \"%s\" failed",
+                      host_dev_name);
+        exit(1);
+    }
+
+    if (can_bus_insert_client(bus, &c->bus_client) < 0) {
+        error_report("CAN host device \"%s\" connect to bus \"%s\" failed",
+                      host_dev_name, bus->name);
+        exit(1);
+    }
+
+    if (0) {
+        /*
+         * Not used there or as a CanBusSocketcanConnectState method
+         * for now but included there for documentation purposes
+         * and to suppress warning.
+         */
+        can_bus_socketcan_set_filters(&c->bus_client, NULL, 0);
+    }
+
+    return 0;
+}
+
+int (*can_bus_connect_to_host_variant)(CanBusState *bus, const char *name) =
+        can_bus_connect_to_host_socketcan;
-- 
2.11.0