1 files changed, 331 insertions, 0 deletions
diff --git a/net/tap-linux.c b/net/tap-linux.c
new file mode 100644
index 000000000..958476974
--- /dev/null
+++ b/net/tap-linux.c
@@ -0,0 +1,331 @@
+/*
+ * QEMU System Emulator
+ *
+ * Copyright (c) 2003-2008 Fabrice Bellard
+ * Copyright (c) 2009 Red Hat, Inc.
+ *
+ * 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-common.h"
+#include "tap_int.h"
+#include "tap-linux.h"
+#include "net/tap.h"
+
+#include <net/if.h>
+#include <sys/ioctl.h>
+
+#include "qapi/error.h"
+#include "qemu/error-report.h"
+#include "qemu/cutils.h"
+
+#define PATH_NET_TUN "/dev/net/tun"
+
+int tap_open(char *ifname, int ifname_size, int *vnet_hdr,
+             int vnet_hdr_required, int mq_required, Error **errp)
+{
+    struct ifreq ifr;
+    int fd, ret;
+    int len = sizeof(struct virtio_net_hdr);
+    unsigned int features;
+
+    TFR(fd = open(PATH_NET_TUN, O_RDWR));
+    if (fd < 0) {
+        error_setg_errno(errp, errno, "could not open %s", PATH_NET_TUN);
+        return -1;
+    }
+    memset(&ifr, 0, sizeof(ifr));
+    ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
+
+    if (ioctl(fd, TUNGETFEATURES, &features) == -1) {
+        warn_report("TUNGETFEATURES failed: %s", strerror(errno));
+        features = 0;
+    }
+
+    if (features & IFF_ONE_QUEUE) {
+        ifr.ifr_flags |= IFF_ONE_QUEUE;
+    }
+
+    if (*vnet_hdr) {
+        if (features & IFF_VNET_HDR) {
+            *vnet_hdr = 1;
+            ifr.ifr_flags |= IFF_VNET_HDR;
+        } else {
+            *vnet_hdr = 0;
+        }
+
+        if (vnet_hdr_required && !*vnet_hdr) {
+            error_setg(errp, "vnet_hdr=1 requested, but no kernel "
+                       "support for IFF_VNET_HDR available");
+            close(fd);
+            return -1;
+        }
+        /*
+         * Make sure vnet header size has the default value: for a persistent
+         * tap it might have been modified e.g. by another instance of qemu.
+         * Ignore errors since old kernels do not support this ioctl: in this
+         * case the header size implicitly has the correct value.
+         */
+        ioctl(fd, TUNSETVNETHDRSZ, &len);
+    }
+
+    if (mq_required) {
+        if (!(features & IFF_MULTI_QUEUE)) {
+            error_setg(errp, "multiqueue required, but no kernel "
+                       "support for IFF_MULTI_QUEUE available");
+            close(fd);
+            return -1;
+        } else {
+            ifr.ifr_flags |= IFF_MULTI_QUEUE;
+        }
+    }
+
+    if (ifname[0] != '\0')
+        pstrcpy(ifr.ifr_name, IFNAMSIZ, ifname);
+    else
+        pstrcpy(ifr.ifr_name, IFNAMSIZ, "tap%d");
+    ret = ioctl(fd, TUNSETIFF, (void *) &ifr);
+    if (ret != 0) {
+        if (ifname[0] != '\0') {
+            error_setg_errno(errp, errno, "could not configure %s (%s)",
+                             PATH_NET_TUN, ifr.ifr_name);
+        } else {
+            error_setg_errno(errp, errno, "could not configure %s",
+                             PATH_NET_TUN);
+        }
+        close(fd);
+        return -1;
+    }
+    pstrcpy(ifname, ifname_size, ifr.ifr_name);
+    fcntl(fd, F_SETFL, O_NONBLOCK);
+    return fd;
+}
+
+/* sndbuf implements a kind of flow control for tap.
+ * Unfortunately when it's enabled, and packets are sent
+ * to other guests on the same host, the receiver
+ * can lock up the transmitter indefinitely.
+ *
+ * To avoid packet loss, sndbuf should be set to a value lower than the tx
+ * queue capacity of any destination network interface.
+ * Ethernet NICs generally have txqueuelen=1000, so 1Mb is
+ * a good value, given a 1500 byte MTU.
+ */
+#define TAP_DEFAULT_SNDBUF 0
+
+void tap_set_sndbuf(int fd, const NetdevTapOptions *tap, Error **errp)
+{
+    int sndbuf;
+
+    sndbuf = !tap->has_sndbuf       ? TAP_DEFAULT_SNDBUF :
+             tap->sndbuf > INT_MAX  ? INT_MAX :
+             tap->sndbuf;
+
+    if (!sndbuf) {
+        sndbuf = INT_MAX;
+    }
+
+    if (ioctl(fd, TUNSETSNDBUF, &sndbuf) == -1 && tap->has_sndbuf) {
+        error_setg_errno(errp, errno, "TUNSETSNDBUF ioctl failed");
+    }
+}
+
+int tap_probe_vnet_hdr(int fd, Error **errp)
+{
+    struct ifreq ifr;
+
+    if (ioctl(fd, TUNGETIFF, &ifr) != 0) {
+        /* TUNGETIFF is available since kernel v2.6.27 */
+        error_setg_errno(errp, errno,
+                         "Unable to query TUNGETIFF on FD %d", fd);
+        return -1;
+    }
+
+    return ifr.ifr_flags & IFF_VNET_HDR;
+}
+
+int tap_probe_has_ufo(int fd)
+{
+    unsigned offload;
+
+    offload = TUN_F_CSUM | TUN_F_UFO;
+
+    if (ioctl(fd, TUNSETOFFLOAD, offload) < 0)
+        return 0;
+
+    return 1;
+}
+
+/* Verify that we can assign given length */
+int tap_probe_vnet_hdr_len(int fd, int len)
+{
+    int orig;
+    if (ioctl(fd, TUNGETVNETHDRSZ, &orig) == -1) {
+        return 0;
+    }
+    if (ioctl(fd, TUNSETVNETHDRSZ, &len) == -1) {
+        return 0;
+    }
+    /* Restore original length: we can't handle failure. */
+    if (ioctl(fd, TUNSETVNETHDRSZ, &orig) == -1) {
+        fprintf(stderr, "TUNGETVNETHDRSZ ioctl() failed: %s. Exiting.\n",
+                strerror(errno));
+        abort();
+        return -errno;
+    }
+    return 1;
+}
+
+void tap_fd_set_vnet_hdr_len(int fd, int len)
+{
+    if (ioctl(fd, TUNSETVNETHDRSZ, &len) == -1) {
+        fprintf(stderr, "TUNSETVNETHDRSZ ioctl() failed: %s. Exiting.\n",
+                strerror(errno));
+        abort();
+    }
+}
+
+int tap_fd_set_vnet_le(int fd, int is_le)
+{
+    int arg = is_le ? 1 : 0;
+
+    if (!ioctl(fd, TUNSETVNETLE, &arg)) {
+        return 0;
+    }
+
+    /* Check if our kernel supports TUNSETVNETLE */
+    if (errno == EINVAL) {
+        return -errno;
+    }
+
+    error_report("TUNSETVNETLE ioctl() failed: %s.", strerror(errno));
+    abort();
+}
+
+int tap_fd_set_vnet_be(int fd, int is_be)
+{
+    int arg = is_be ? 1 : 0;
+
+    if (!ioctl(fd, TUNSETVNETBE, &arg)) {
+        return 0;
+    }
+
+    /* Check if our kernel supports TUNSETVNETBE */
+    if (errno == EINVAL) {
+        return -errno;
+    }
+
+    error_report("TUNSETVNETBE ioctl() failed: %s.", strerror(errno));
+    abort();
+}
+
+void tap_fd_set_offload(int fd, int csum, int tso4,
+                        int tso6, int ecn, int ufo)
+{
+    unsigned int offload = 0;
+
+    /* Check if our kernel supports TUNSETOFFLOAD */
+    if (ioctl(fd, TUNSETOFFLOAD, 0) != 0 && errno == EINVAL) {
+        return;
+    }
+
+    if (csum) {
+        offload |= TUN_F_CSUM;
+        if (tso4)
+            offload |= TUN_F_TSO4;
+        if (tso6)
+            offload |= TUN_F_TSO6;
+        if ((tso4 || tso6) && ecn)
+            offload |= TUN_F_TSO_ECN;
+        if (ufo)
+            offload |= TUN_F_UFO;
+    }
+
+    if (ioctl(fd, TUNSETOFFLOAD, offload) != 0) {
+        offload &= ~TUN_F_UFO;
+        if (ioctl(fd, TUNSETOFFLOAD, offload) != 0) {
+            fprintf(stderr, "TUNSETOFFLOAD ioctl() failed: %s\n",
+                    strerror(errno));
+        }
+    }
+}
+
+/* Enable a specific queue of tap. */
+int tap_fd_enable(int fd)
+{
+    struct ifreq ifr;
+    int ret;
+
+    memset(&ifr, 0, sizeof(ifr));
+
+    ifr.ifr_flags = IFF_ATTACH_QUEUE;
+    ret = ioctl(fd, TUNSETQUEUE, (void *) &ifr);
+
+    if (ret != 0) {
+        error_report("could not enable queue");
+    }
+
+    return ret;
+}
+
+/* Disable a specific queue of tap/ */
+int tap_fd_disable(int fd)
+{
+    struct ifreq ifr;
+    int ret;
+
+    memset(&ifr, 0, sizeof(ifr));
+
+    ifr.ifr_flags = IFF_DETACH_QUEUE;
+    ret = ioctl(fd, TUNSETQUEUE, (void *) &ifr);
+
+    if (ret != 0) {
+        error_report("could not disable queue");
+    }
+
+    return ret;
+}
+
+int tap_fd_get_ifname(int fd, char *ifname)
+{
+    struct ifreq ifr;
+
+    if (ioctl(fd, TUNGETIFF, &ifr) != 0) {
+        error_report("TUNGETIFF ioctl() failed: %s",
+                     strerror(errno));
+        return -1;
+    }
+
+    pstrcpy(ifname, sizeof(ifr.ifr_name), ifr.ifr_name);
+    return 0;
+}
+
+int tap_fd_set_steering_ebpf(int fd, int prog_fd)
+{
+    if (ioctl(fd, TUNSETSTEERINGEBPF, (void *) &prog_fd) != 0) {
+        error_report("Issue while setting TUNSETSTEERINGEBPF:"
+                    " %s with fd: %d, prog_fd: %d",
+                    strerror(errno), fd, prog_fd);
+
+       return -1;
+    }
+
+    return 0;
+}