Archipelago » qemu

/*

 * 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 "net/tap.h"

#include "config-host.h"

#include <signal.h>

#include <sys/ioctl.h>

#include <sys/stat.h>

#include <sys/wait.h>

#include <net/if.h>

#include "net.h"

#include "sysemu.h"

#include "qemu-char.h"

#include "qemu-common.h"

#ifdef __linux__

#include "net/tap-linux.h"

#endif

#if !defined(_AIX)

/* Maximum GSO packet size (64k) plus plenty of room for

 * the ethernet and virtio_net headers

 */

#define TAP_BUFSIZE (4096 + 65536)

typedef struct TAPState {

    VLANClientState *vc;

    int fd;

    char down_script[1024];

    char down_script_arg[128];

    uint8_t buf[TAP_BUFSIZE];

    unsigned int read_poll : 1;

    unsigned int write_poll : 1;

    unsigned int has_vnet_hdr : 1;

    unsigned int using_vnet_hdr : 1;

    unsigned int has_ufo: 1;

} TAPState;

static int launch_script(const char *setup_script, const char *ifname, int fd);

static int tap_can_send(void *opaque);

static void tap_send(void *opaque);

static void tap_writable(void *opaque);

static void tap_update_fd_handler(TAPState *s)

{

    qemu_set_fd_handler2(s->fd,

                         s->read_poll  ? tap_can_send : NULL,

                         s->read_poll  ? tap_send     : NULL,

                         s->write_poll ? tap_writable : NULL,

                         s);

}

static void tap_read_poll(TAPState *s, int enable)

{

    s->read_poll = !!enable;

    tap_update_fd_handler(s);

}

static void tap_write_poll(TAPState *s, int enable)

{

    s->write_poll = !!enable;

    tap_update_fd_handler(s);

}

static void tap_writable(void *opaque)

{

    TAPState *s = opaque;

    tap_write_poll(s, 0);

    qemu_flush_queued_packets(s->vc);

}

static ssize_t tap_write_packet(TAPState *s, const struct iovec *iov, int iovcnt)

{

    ssize_t len;

    do {

        len = writev(s->fd, iov, iovcnt);

    } while (len == -1 && errno == EINTR);

    if (len == -1 && errno == EAGAIN) {

        tap_write_poll(s, 1);

        return 0;

    }

    return len;

}

static ssize_t tap_receive_iov(VLANClientState *vc, const struct iovec *iov,

                               int iovcnt)

{

    TAPState *s = vc->opaque;

    const struct iovec *iovp = iov;

    struct iovec iov_copy[iovcnt + 1];

    struct virtio_net_hdr hdr = { 0, };

    if (s->has_vnet_hdr && !s->using_vnet_hdr) {

        iov_copy[0].iov_base = &hdr;

        iov_copy[0].iov_len =  sizeof(hdr);

        memcpy(&iov_copy[1], iov, iovcnt * sizeof(*iov));

        iovp = iov_copy;

        iovcnt++;

    }

    return tap_write_packet(s, iovp, iovcnt);

}

static ssize_t tap_receive_raw(VLANClientState *vc, const uint8_t *buf, size_t size)

{

    TAPState *s = vc->opaque;

    struct iovec iov[2];

    int iovcnt = 0;

    struct virtio_net_hdr hdr = { 0, };

    if (s->has_vnet_hdr) {

        iov[iovcnt].iov_base = &hdr;

        iov[iovcnt].iov_len  = sizeof(hdr);

        iovcnt++;

    }

    iov[iovcnt].iov_base = (char *)buf;

    iov[iovcnt].iov_len  = size;

    iovcnt++;

    return tap_write_packet(s, iov, iovcnt);

}

static ssize_t tap_receive(VLANClientState *vc, const uint8_t *buf, size_t size)

{

    TAPState *s = vc->opaque;

    struct iovec iov[1];

    if (s->has_vnet_hdr && !s->using_vnet_hdr) {

        return tap_receive_raw(vc, buf, size);

    }

    iov[0].iov_base = (char *)buf;

    iov[0].iov_len  = size;

    return tap_write_packet(s, iov, 1);

}

static int tap_can_send(void *opaque)

{

    TAPState *s = opaque;

    return qemu_can_send_packet(s->vc);

}

#ifndef __sun__

ssize_t tap_read_packet(int tapfd, uint8_t *buf, int maxlen)

{

    return read(tapfd, buf, maxlen);

}

#endif

static void tap_send_completed(VLANClientState *vc, ssize_t len)

{

    TAPState *s = vc->opaque;

    tap_read_poll(s, 1);

}

static void tap_send(void *opaque)

{

    TAPState *s = opaque;

    int size;

    do {

        uint8_t *buf = s->buf;

        size = tap_read_packet(s->fd, s->buf, sizeof(s->buf));

        if (size <= 0) {

            break;

        }

        if (s->has_vnet_hdr && !s->using_vnet_hdr) {

            buf  += sizeof(struct virtio_net_hdr);

            size -= sizeof(struct virtio_net_hdr);

        }

        size = qemu_send_packet_async(s->vc, buf, size, tap_send_completed);

        if (size == 0) {

            tap_read_poll(s, 0);

        }

    } while (size > 0);

}

/* 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.

 */

#define TAP_DEFAULT_SNDBUF 1024*1024

static int tap_set_sndbuf(TAPState *s, QemuOpts *opts)

{

    int sndbuf;

    sndbuf = qemu_opt_get_size(opts, "sndbuf", TAP_DEFAULT_SNDBUF);

    if (!sndbuf) {

        sndbuf = INT_MAX;

    }

    if (ioctl(s->fd, TUNSETSNDBUF, &sndbuf) == -1 && qemu_opt_get(opts, "sndbuf")) {

        qemu_error("TUNSETSNDBUF ioctl failed: %s\n", strerror(errno));

        return -1;

    }

    return 0;

}

int tap_has_ufo(VLANClientState *vc)

{

    TAPState *s = vc->opaque;

    assert(vc->type == NET_CLIENT_TYPE_TAP);

    return s->has_ufo;

}

int tap_has_vnet_hdr(VLANClientState *vc)

{

    TAPState *s = vc->opaque;

    assert(vc->type == NET_CLIENT_TYPE_TAP);

    return s->has_vnet_hdr;

}

void tap_using_vnet_hdr(VLANClientState *vc, int using_vnet_hdr)

{

    TAPState *s = vc->opaque;

    using_vnet_hdr = using_vnet_hdr != 0;

    assert(vc->type == NET_CLIENT_TYPE_TAP);

    assert(s->has_vnet_hdr == using_vnet_hdr);

    s->using_vnet_hdr = using_vnet_hdr;

}

static int tap_probe_vnet_hdr(int fd)

{

    struct ifreq ifr;

    if (ioctl(fd, TUNGETIFF, &ifr) != 0) {

        qemu_error("TUNGETIFF ioctl() failed: %s\n", strerror(errno));

        return 0;

    }

    return ifr.ifr_flags & IFF_VNET_HDR;

}

void tap_set_offload(VLANClientState *vc, int csum, int tso4,

                     int tso6, int ecn, int ufo)

{

    TAPState *s = vc->opaque;

    unsigned int offload = 0;

    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(s->fd, TUNSETOFFLOAD, offload) != 0) {

        offload &= ~TUN_F_UFO;

        if (ioctl(s->fd, TUNSETOFFLOAD, offload) != 0) {

            fprintf(stderr, "TUNSETOFFLOAD ioctl() failed: %s\n",

                    strerror(errno));

        }

    }

}

static void tap_cleanup(VLANClientState *vc)

{

    TAPState *s = vc->opaque;

    qemu_purge_queued_packets(vc);

    if (s->down_script[0])

        launch_script(s->down_script, s->down_script_arg, s->fd);

    tap_read_poll(s, 0);

    tap_write_poll(s, 0);

    close(s->fd);

    qemu_free(s);

}

/* fd support */

static TAPState *net_tap_fd_init(VLANState *vlan,

                                 const char *model,

                                 const char *name,

                                 int fd,

                                 int vnet_hdr)

{

    TAPState *s;

    unsigned int offload;

    s = qemu_mallocz(sizeof(TAPState));

    s->fd = fd;

    s->has_vnet_hdr = vnet_hdr != 0;

    s->using_vnet_hdr = 0;

    s->vc = qemu_new_vlan_client(NET_CLIENT_TYPE_TAP,

                                 vlan, NULL, model, name, NULL,

                                 tap_receive, tap_receive_raw,

                                 tap_receive_iov, tap_cleanup, s);

    s->has_ufo = 0;

    /* Check if tap supports UFO */

    offload = TUN_F_CSUM | TUN_F_UFO;

    if (ioctl(s->fd, TUNSETOFFLOAD, offload) == 0)

       s->has_ufo = 1;

    tap_set_offload(s->vc, 0, 0, 0, 0, 0);

    tap_read_poll(s, 1);

    return s;

}

#ifdef _AIX

int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int vnet_hdr_required)

{

    fprintf (stderr, "no tap on AIX\n");

    return -1;

}

#else

int tap_open(char *ifname, int ifname_size, int *vnet_hdr, int vnet_hdr_required)

{

    struct ifreq ifr;

    int fd, ret;

    TFR(fd = open("/dev/net/tun", O_RDWR));

    if (fd < 0) {

        fprintf(stderr, "warning: could not open /dev/net/tun: no virtual network emulation\n");

        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;

        }

        if (vnet_hdr_required && !*vnet_hdr) {

            qemu_error("vnet_hdr=1 requested, but no kernel "

                       "support for IFF_VNET_HDR available");

            close(fd);

            return -1;

        }

    }

    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) {

        fprintf(stderr, "warning: could not configure /dev/net/tun: no virtual network emulation\n");

        close(fd);

        return -1;

    }

    pstrcpy(ifname, ifname_size, ifr.ifr_name);

    fcntl(fd, F_SETFL, O_NONBLOCK);

    return fd;

}

#endif

static int launch_script(const char *setup_script, const char *ifname, int fd)

{

    sigset_t oldmask, mask;

    int pid, status;

    char *args[3];

    char **parg;

    sigemptyset(&mask);

    sigaddset(&mask, SIGCHLD);

    sigprocmask(SIG_BLOCK, &mask, &oldmask);

    /* try to launch network script */

    pid = fork();

    if (pid == 0) {

        int open_max = sysconf(_SC_OPEN_MAX), i;

        for (i = 0; i < open_max; i++) {

            if (i != STDIN_FILENO &&

                i != STDOUT_FILENO &&

                i != STDERR_FILENO &&

                i != fd) {

                close(i);

            }

        }

        parg = args;

        *parg++ = (char *)setup_script;

        *parg++ = (char *)ifname;

        *parg++ = NULL;

        execv(setup_script, args);

        _exit(1);

    } else if (pid > 0) {

        while (waitpid(pid, &status, 0) != pid) {

            /* loop */

        }

        sigprocmask(SIG_SETMASK, &oldmask, NULL);

        if (WIFEXITED(status) && WEXITSTATUS(status) == 0) {

            return 0;

        }

    }

    fprintf(stderr, "%s: could not launch network script\n", setup_script);

    return -1;

}

static int net_tap_init(QemuOpts *opts, int *vnet_hdr)

{

    int fd, vnet_hdr_required;

    char ifname[128] = {0,};

    const char *setup_script;

    if (qemu_opt_get(opts, "ifname")) {

        pstrcpy(ifname, sizeof(ifname), qemu_opt_get(opts, "ifname"));

    }

    *vnet_hdr = qemu_opt_get_bool(opts, "vnet_hdr", 1);

    if (qemu_opt_get(opts, "vnet_hdr")) {

        vnet_hdr_required = *vnet_hdr;

    } else {

        vnet_hdr_required = 0;

    }

    TFR(fd = tap_open(ifname, sizeof(ifname), vnet_hdr, vnet_hdr_required));

    if (fd < 0) {

        return -1;

    }

    setup_script = qemu_opt_get(opts, "script");

    if (setup_script &&

        setup_script[0] != '\0' &&

        strcmp(setup_script, "no") != 0 &&

        launch_script(setup_script, ifname, fd)) {

        close(fd);

        return -1;

    }

    qemu_opt_set(opts, "ifname", ifname);

    return fd;

}

int net_init_tap(QemuOpts *opts, Monitor *mon, const char *name, VLANState *vlan)

{

    TAPState *s;

    int fd, vnet_hdr;

    if (qemu_opt_get(opts, "fd")) {

        if (qemu_opt_get(opts, "ifname") ||

            qemu_opt_get(opts, "script") ||

            qemu_opt_get(opts, "downscript") ||

            qemu_opt_get(opts, "vnet_hdr")) {

            qemu_error("ifname=, script=, downscript= and vnet_hdr= is invalid with fd=\n");

            return -1;

        }

        fd = net_handle_fd_param(mon, qemu_opt_get(opts, "fd"));

        if (fd == -1) {

            return -1;

        }

        fcntl(fd, F_SETFL, O_NONBLOCK);

        vnet_hdr = tap_probe_vnet_hdr(fd);

    } else {

        if (!qemu_opt_get(opts, "script")) {

            qemu_opt_set(opts, "script", DEFAULT_NETWORK_SCRIPT);

        }

        if (!qemu_opt_get(opts, "downscript")) {

            qemu_opt_set(opts, "downscript", DEFAULT_NETWORK_DOWN_SCRIPT);

        }

        fd = net_tap_init(opts, &vnet_hdr);

    }

    s = net_tap_fd_init(vlan, "tap", name, fd, vnet_hdr);

    if (!s) {

        close(fd);

        return -1;

    }

    if (tap_set_sndbuf(s, opts) < 0) {

        return -1;

    }

    if (qemu_opt_get(opts, "fd")) {

        snprintf(s->vc->info_str, sizeof(s->vc->info_str), "fd=%d", fd);

    } else {

        const char *ifname, *script, *downscript;

        ifname     = qemu_opt_get(opts, "ifname");

        script     = qemu_opt_get(opts, "script");

        downscript = qemu_opt_get(opts, "downscript");

        snprintf(s->vc->info_str, sizeof(s->vc->info_str),

                 "ifname=%s,script=%s,downscript=%s",

                 ifname, script, downscript);

        if (strcmp(downscript, "no") != 0) {

            snprintf(s->down_script, sizeof(s->down_script), "%s", downscript);

            snprintf(s->down_script_arg, sizeof(s->down_script_arg), "%s", ifname);

        }

    }

    if (vlan) {

        vlan->nb_host_devs++;

    }

    return 0;

}

#endif /* !defined(_AIX) */