* THE SOFTWARE.
*/
+#include "tap_int.h"
+#include "tap-linux.h"
#include "net/tap.h"
-#include "net/tap-linux.h"
#include <net/if.h>
#include <sys/ioctl.h>
-#include "sysemu.h"
+#include "sysemu/sysemu.h"
#include "qemu-common.h"
-#include "qemu-error.h"
+#include "qemu/error-report.h"
-int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int vnet_hdr_required)
+#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)
{
struct ifreq ifr;
int fd, ret;
+ int len = sizeof(struct virtio_net_hdr);
+ unsigned int features;
- TFR(fd = open("/dev/net/tun", O_RDWR));
+ TFR(fd = open(PATH_NET_TUN, O_RDWR));
if (fd < 0) {
- fprintf(stderr, "warning: could not open /dev/net/tun: no virtual network emulation\n");
+ error_report("could not open %s: %m", PATH_NET_TUN);
return -1;
}
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
- if (*vnet_hdr) {
- unsigned int features;
+ if (ioctl(fd, TUNGETFEATURES, &features) == 0 &&
+ features & IFF_ONE_QUEUE) {
+ ifr.ifr_flags |= IFF_ONE_QUEUE;
+ }
+ if (*vnet_hdr) {
if (ioctl(fd, TUNGETFEATURES, &features) == 0 &&
features & IFF_VNET_HDR) {
*vnet_hdr = 1;
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 ((ioctl(fd, TUNGETFEATURES, &features) != 0) ||
+ !(features & IFF_MULTI_QUEUE)) {
+ error_report("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, "tap%d");
ret = ioctl(fd, TUNSETIFF, (void *) &ifr);
if (ret != 0) {
- fprintf(stderr, "warning: could not configure /dev/net/tun: no virtual network emulation\n");
+ if (ifname[0] != '\0') {
+ error_report("could not configure %s (%s): %m", PATH_NET_TUN, ifr.ifr_name);
+ } else {
+ error_report("could not configure %s: %m", PATH_NET_TUN);
+ }
close(fd);
return -1;
}
return fd;
}
-/* sndbuf should be set to a value lower than the tx queue
- * capacity of any destination network interface.
+/* 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 default, given a 1500 byte MTU.
+ * a good value, given a 1500 byte MTU.
*/
-#define TAP_DEFAULT_SNDBUF 1024*1024
+#define TAP_DEFAULT_SNDBUF 0
-int tap_set_sndbuf(int fd, QemuOpts *opts)
+int tap_set_sndbuf(int fd, const NetdevTapOptions *tap)
{
int sndbuf;
- sndbuf = qemu_opt_get_size(opts, "sndbuf", TAP_DEFAULT_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 && qemu_opt_get(opts, "sndbuf")) {
+ if (ioctl(fd, TUNSETSNDBUF, &sndbuf) == -1 && tap->has_sndbuf) {
error_report("TUNSETSNDBUF ioctl failed: %s", strerror(errno));
return -1;
}
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();
+ }
+}
+
void tap_fd_set_offload(int fd, int csum, int tso4,
int tso6, int ecn, int ufo)
{
}
}
}
+
+/* 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;
+}
projects / qemu.git / blobdiff