Migrate virtio-net from semu

src/devices/netdev.c

@@ -0,0 +1,116 @@
+/*
+ * rv32emu is freely redistributable under the MIT License. See the file
+ * "LICENSE" for information on usage and redistribution of this file.
+ */
+
+#include "netdev.h"
+
+#include <stdbool.h>
+#include <string.h>
+
+#include "utils.h"
+
+#if defined(__linux__) && !defined(__EMSCRIPTEN__)
+
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/if.h>
+#include <linux/if_tun.h>
+#include <stdlib.h>
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+static int net_init_tap(netdev_t *netdev)
+{
+    net_tap_options_t *tap = (net_tap_options_t *) netdev->op;
+
+    tap->tap_fd = open("/dev/net/tun", O_RDWR);
+    if (tap->tap_fd < 0) {
+        rv_log_error("failed to open TAP device: %s", strerror(errno));
+        return -1;
+    }
+
+    struct ifreq ifreq = {
+        .ifr_flags = IFF_TAP | IFF_NO_PI,
+    };
+
+    strncpy(ifreq.ifr_name, "tap%d", sizeof(ifreq.ifr_name) - 1);
+
+    if (ioctl(tap->tap_fd, TUNSETIFF, &ifreq) < 0) {
+        rv_log_error("failed to allocate TAP device: %s", strerror(errno));
+        close(tap->tap_fd);
+        tap->tap_fd = -1;
+        return -1;
+    }
+
+    rv_log_info("allocated TAP interface: %s", ifreq.ifr_name);
+
+    if (fcntl(tap->tap_fd, F_SETFL,
+              fcntl(tap->tap_fd, F_GETFL, 0) | O_NONBLOCK) < 0) {
+        rv_log_error("failed to set TAP non-blocking mode: %s",
+                     strerror(errno));
+        close(tap->tap_fd);
+        tap->tap_fd = -1;
+        return -1;
+    }
+
+    return 0;
+}
+
+bool netdev_init(netdev_t *netdev, const char *net_type)
+{
+    if (!netdev || !net_type || strcmp(net_type, "tap"))
+        return false;
+
+    netdev->name = (char *) net_type;
+    netdev->type = NETDEV_IMPL_tap;
+    netdev->op = calloc(1, sizeof(net_tap_options_t));
+    if (!netdev->op)
+        return false;
+
+    if (net_init_tap(netdev) < 0) {
+        free(netdev->op);
+        netdev->op = NULL;
+        return false;
+    }
+
+    return true;
+}
+
+void netdev_delete(netdev_t *netdev)
+{
+    if (!netdev || !netdev->op)
+        return;
+
+    switch (netdev->type) {
+    case NETDEV_IMPL_tap: {
+        net_tap_options_t *tap = (net_tap_options_t *) netdev->op;
+        if (tap->tap_fd >= 0)
+            close(tap->tap_fd);
+        break;
+    }
+    default:
+        break;
+    }
+
+    free(netdev->op);
+    netdev->op = NULL;
+}
+
+#else
+
+bool netdev_init(netdev_t *netdev, const char *net_type)
+{
+    (void) netdev;
+    (void) net_type;
+
+    rv_log_error("virtio-net TAP backend is only supported on Linux hosts");
+    return false;
+}
+
+void netdev_delete(netdev_t *netdev)
+{
+    (void) netdev;
+}
+
+#endif

src/devices/netdev.h

@@ -0,0 +1,28 @@
+/*
+ * rv32emu is freely redistributable under the MIT License. See the file
+ * "LICENSE" for information on usage and redistribution of this file.
+ */
+
+#pragma once
+
+#include <stdbool.h>
+
+typedef struct netdev netdev_t;
+
+typedef enum {
+    NETDEV_IMPL_tap,
+} netdev_impl_t;
+
+typedef struct {
+    int tap_fd;
+} net_tap_options_t;
+
+struct netdev {
+    char *name;
+    netdev_impl_t type;
+    void *op;
+};
+
+bool netdev_init(netdev_t *netdev, const char *net_type);
+
+void netdev_delete(netdev_t *netdev);