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libhermit/tools/uhyve-net.c
Stefan Lankes c6157e3ef7 use interrupts to notifiy incoming packets
=> avoid busy waiting in uhyve's network adapter
2017-09-18 00:23:09 +02:00

189 lines
5.1 KiB
C
Executable file

/* Copyright (c) 2015, IBM
* Author(s): Dan Williams <djwillia@us.ibm.com>
* Ricardo Koller <kollerr@us.ibm.com>
* Copyright (c) 2017, RWTH Aachen University
* Author(s): Tim van de Kamp <tim.van.de.kamp@rwth-aachen.de>
*
* Permission to use, copy, modify, and/or distribute this software
* for any purpose with or without fee is hereby granted, provided
* that the above copyright notice and this permission notice appear
* in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
* WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE
* AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR
* CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
* OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
* NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
* CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
/* We used several existing projects as guides
* kvmtest.c: http://lwn.net/Articles/658512/
* lkvm: http://github.com/clearlinux/kvmtool
*/
/*
* 15.1.2017: extend original version (https://github.com/Solo5/solo5)
* for HermitCore
*/
#include "uhyve-net.h"
#include <ctype.h>
/* TODO: create an array or equal for more then one netif */
static uhyve_netinfo_t netinfo;
//-------------------------------------- ATTACH LINUX TAP -----------------------------------------//
int attach_linux_tap(const char *dev)
{
struct ifreq ifr;
int fd, err;
// @<number> indicates a pre-existing open fd onto the correct device.
if (dev[0] == '@') {
fd = atoi(&dev[1]);
if (fcntl(fd, F_SETFL, O_NONBLOCK) == -1)
return -1;
return fd;
}
fd = open("/dev/net/tun", O_RDWR | O_NONBLOCK);
// Initialize interface request for TAP interface
memset(&ifr, 0x00, sizeof(ifr));
ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
if (strlen(dev) > IFNAMSIZ) {
errno = EINVAL;
return -1;
}
strncpy(ifr.ifr_name, dev, IFNAMSIZ);
// Try to create OR attach to an existing device. The Linux API has no way
// to differentiate between the two
// create before a tap device with these commands:
//
// sudo ip tuntap add <devname> mode tap user <user>
// sudo ip addr add 10.0.5.1/24 broadcast 10.0.5.255
// sudo ip link set dev <devname> up
//
if (ioctl(fd, TUNSETIFF, (void *)&ifr) < 0) {
err = errno;
close(fd);
errno = err;
return -1;
}
// If we got back a different device than the one requested, e.g. because
// the caller mistakenly passed in '%d' (yes, that's really in the Linux API)
// then fail
if (strncmp(ifr.ifr_name, dev, IFNAMSIZ) != 0) {
close(fd);
errno = ENODEV;
return -1;
}
// Attempt a zero-sized write to the device. If the device was freshly created
// (as opposed to attached to an existing ine) this will fail with EIO. Ignore
// any other error return since that may indicate the device is up
//
// If this check produces a false positive then caller's later writes to fd will
// fali with EIO, which is not great but at least we tried
char buf[1] = { 0 };
if (write(fd, buf, 0) == -1 && errno == EIO) {
close(fd);
errno = ENODEV;
return -1;
}
return fd;
}
//---------------------------------- GET MAC ----------------------------------------------//
char* uhyve_get_mac(void)
{
return netinfo.mac_str;
}
//---------------------------------- SET MAC ----------------------------------------------//
int uhyve_set_mac(void)
{
int mac_is_set = 0;
uint8_t guest_mac[6];
char* str = getenv("HERMIT_NETIF_MAC");
if (str)
{
const char *macptr = str;
const char *v_macptr = macptr;
// checking str is a valid MAC address
int i = 0;
int s = 0;
while(*v_macptr) {
if(isxdigit(*v_macptr)) {
i++;
} else if (*v_macptr == ':') {
if (i / 2 - 1 != s++)
break;
} else {
s = -1;
}
v_macptr++;
}
if (i != 12 || s != 5) {
warnx("Malformed mac address: %s\n", macptr);
} else {
snprintf(netinfo.mac_str, sizeof(netinfo.mac_str), "%s", macptr);
mac_is_set = 1;
}
}
if (!mac_is_set) {
int rfd = open("/dev/urandom", O_RDONLY);
if(rfd == -1)
err(1, "Could not open /dev/urandom\n");
int ret;
ret = read(rfd, guest_mac, sizeof(guest_mac));
// compare the number of bytes read with the size of guest_mac
assert(ret == sizeof(guest_mac));
close(rfd);
guest_mac[0] &= 0xfe; // creats a random MAC-address in the locally administered
guest_mac[0] |= 0x02; // address range which can be used without conflict with other public devices
// save the MAC address in the netinfo
snprintf(netinfo.mac_str, sizeof(netinfo.mac_str),
"%02x:%02x:%02x:%02x:%02x:%02x",
guest_mac[0], guest_mac[1], guest_mac[2],
guest_mac[3], guest_mac[4], guest_mac[5]);
}
return 0;
}
//-------------------------------------- SETUP NETWORK ---------------------------------------------//
int uhyve_net_init(const char *netif)
{
if (netif == NULL) {
err(1, "ERROR: no netif defined\n");
return -1;
}
// attaching netif
netfd = attach_linux_tap(netif);
if (netfd < 0) {
err(1, "Could not attach interface: %s\n", netif);
exit(1);
}
uhyve_set_mac();
return netfd;
}