| /* |
| * 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 "tap_int.h" |
| #include "tap-linux.h" |
| #include "net/tap.h" |
| |
| #include <net/if.h> |
| #include <sys/ioctl.h> |
| |
| #include "sysemu/sysemu.h" |
| #include "qemu-common.h" |
| #include "qemu/error-report.h" |
| |
| #define PATH_NET_TUN "/dev/net/tun" |
| |
| int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int vnet_hdr_required) |
| { |
| struct ifreq ifr; |
| int fd, ret; |
| int len = sizeof(struct virtio_net_hdr); |
| |
| TFR(fd = open(PATH_NET_TUN, O_RDWR)); |
| if (fd < 0) { |
| 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_VNET_HDR) { |
| *vnet_hdr = 1; |
| ifr.ifr_flags |= IFF_VNET_HDR; |
| } else { |
| *vnet_hdr = 0; |
| } |
| |
| if (vnet_hdr_required && !*vnet_hdr) { |
| error_report("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 (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_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; |
| } |
| 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 |
| |
| int tap_set_sndbuf(int fd, const NetdevTapOptions *tap) |
| { |
| 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_report("TUNSETSNDBUF ioctl failed: %s", strerror(errno)); |
| return -1; |
| } |
| return 0; |
| } |
| |
| int tap_probe_vnet_hdr(int fd) |
| { |
| struct ifreq ifr; |
| |
| if (ioctl(fd, TUNGETIFF, &ifr) != 0) { |
| error_report("TUNGETIFF ioctl() failed: %s", strerror(errno)); |
| return 0; |
| } |
| |
| 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)); |
| assert(0); |
| 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)); |
| assert(0); |
| } |
| } |
| |
| 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)); |
| } |
| } |
| } |