libvirt/src/bridge.c

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/*
* Copyright (C) 2007 Red Hat, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* Authors:
* Mark McLoughlin <markmc@redhat.com>
*/
#include <config.h>
#ifdef WITH_QEMU
#include "bridge.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <paths.h>
#include <sys/wait.h>
#include <linux/param.h> /* HZ */
#include <linux/sockios.h> /* SIOCBRADDBR etc. */
#include <linux/if_bridge.h> /* SYSFS_BRIDGE_ATTR */
#include <linux/if_tun.h> /* IFF_TUN, IFF_NO_PI */
#include <net/if_arp.h> /* ARPHRD_ETHER */
#include "internal.h"
#define MAX_BRIDGE_ID 256
#define JIFFIES_TO_MS(j) (((j)*1000)/HZ)
#define MS_TO_JIFFIES(ms) (((ms)*HZ)/1000)
struct _brControl {
int fd;
};
/**
* brInit:
* @ctlp: pointer to bridge control return value
*
* Initialize a new bridge layer. In case of success
* @ctlp will contain a pointer to the new bridge structure.
*
* Returns 0 in case of success, an error code otherwise.
*/
int
brInit(brControl **ctlp)
{
int fd;
int flags;
if (!ctlp || *ctlp)
return EINVAL;
fd = socket(AF_INET, SOCK_STREAM, 0);
if (fd < 0)
return errno;
if ((flags = fcntl(fd, F_GETFD)) < 0 ||
fcntl(fd, F_SETFD, flags | FD_CLOEXEC) < 0) {
int err = errno;
close(fd);
return err;
}
*ctlp = malloc(sizeof(**ctlp));
if (!*ctlp) {
close(fd);
return ENOMEM;
}
(*ctlp)->fd = fd;
return 0;
}
/**
* brShutdown:
* @ctl: pointer to a bridge control
*
* Shutdown the bridge layer and deallocate the associated structures
*/
void
brShutdown(brControl *ctl)
{
if (!ctl)
return;
close(ctl->fd);
ctl->fd = 0;
free(ctl);
}
/**
* brAddBridge:
* @ctl: bridge control pointer
* @nameOrFmt: the bridge name (or name template)
* @name: pointer to @maxlen bytes to store the bridge name
* @maxlen: size of @name array
*
* This function register a new bridge, @nameOrFmt can be either
* a fixed name or a name template with '%d' for dynamic name allocation.
* in either case the final name for the bridge will be stored in @name.
*
* Returns 0 in case of success or an errno code in case of failure.
*/
#ifdef SIOCBRADDBR
int
brAddBridge(brControl *ctl,
const char *nameOrFmt,
char *name,
int maxlen)
{
int id, subst;
if (!ctl || !ctl->fd || !nameOrFmt || !name)
return EINVAL;
if (maxlen >= BR_IFNAME_MAXLEN)
maxlen = BR_IFNAME_MAXLEN;
subst = id = 0;
if (strstr(nameOrFmt, "%d"))
subst = 1;
do {
char try[BR_IFNAME_MAXLEN];
int len;
if (subst) {
len = snprintf(try, maxlen, nameOrFmt, id);
if (len >= maxlen)
return EADDRINUSE;
} else {
len = strlen(nameOrFmt);
if (len >= maxlen - 1)
return EINVAL;
strncpy(try, nameOrFmt, len);
try[len] = '\0';
}
if (ioctl(ctl->fd, SIOCBRADDBR, try) == 0) {
strncpy(name, try, maxlen);
return 0;
}
id++;
} while (subst && id <= MAX_BRIDGE_ID);
return errno;
}
#else
int brAddBridge (brControl *ctl ATTRIBUTE_UNUSED,
const char *nameOrFmt ATTRIBUTE_UNUSED,
char *name ATTRIBUTE_UNUSED,
int maxlen ATTRIBUTE_UNUSED)
{
return EINVAL;
}
#endif
/**
* brDeleteBridge:
* @ctl: bridge control pointer
* @name: the bridge name
*
* Remove a bridge from the layer.
*
* Returns 0 in case of success or an errno code in case of failure.
*/
#ifdef SIOCBRDELBR
int
brDeleteBridge(brControl *ctl,
const char *name)
{
if (!ctl || !ctl->fd || !name)
return EINVAL;
return ioctl(ctl->fd, SIOCBRDELBR, name) == 0 ? 0 : errno;
}
#else
int
brDeleteBridge(brControl *ctl ATTRIBUTE_UNUSED,
const char *name ATTRIBUTE_UNUSED)
{
return EINVAL;
}
#endif
#if defined(SIOCBRADDIF) && defined(SIOCBRDELIF)
static int
brAddDelInterface(brControl *ctl,
int cmd,
const char *bridge,
const char *iface)
{
struct ifreq ifr;
int len;
if (!ctl || !ctl->fd || !bridge || !iface)
return EINVAL;
if ((len = strlen(bridge)) >= BR_IFNAME_MAXLEN)
return EINVAL;
memset(&ifr, 0, sizeof(struct ifreq));
strncpy(ifr.ifr_name, bridge, len);
ifr.ifr_name[len] = '\0';
if (!(ifr.ifr_ifindex = if_nametoindex(iface)))
return ENODEV;
return ioctl(ctl->fd, cmd, &ifr) == 0 ? 0 : errno;
}
#endif
/**
* brAddInterface:
* @ctl: bridge control pointer
* @bridge: the bridge name
* @iface: the network interface name
*
* Adds an interface to a bridge
*
* Returns 0 in case of success or an errno code in case of failure.
*/
#ifdef SIOCBRADDIF
int
brAddInterface(brControl *ctl,
const char *bridge,
const char *iface)
{
return brAddDelInterface(ctl, SIOCBRADDIF, bridge, iface);
}
#else
int
brAddInterface(brControl *ctl ATTRIBUTE_UNUSED,
const char *bridge ATTRIBUTE_UNUSED,
const char *iface ATTRIBUTE_UNUSED)
{
return EINVAL;
}
#endif
/**
* brDeleteInterface:
* @ctl: bridge control pointer
* @bridge: the bridge name
* @iface: the network interface name
*
* Removes an interface from a bridge
*
* Returns 0 in case of success or an errno code in case of failure.
*/
#ifdef SIOCBRDELIF
int
brDeleteInterface(brControl *ctl,
const char *bridge,
const char *iface)
{
return brAddDelInterface(ctl, SIOCBRDELIF, bridge, iface);
}
#else
int
brDeleteInterface(brControl *ctl ATTRIBUTE_UNUSED,
const char *bridge ATTRIBUTE_UNUSED,
const char *iface ATTRIBUTE_UNUSED)
{
return EINVAL;
}
#endif
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/**
* brAddTap:
* @ctl: bridge control pointer
* @bridge: the bridge name
* @ifname: the interface name (or name template)
* @maxlen: size of @ifname array
* @tapfd: file descriptor return value for the new tap device
*
* This function creates a new tap device on a bridge. @ifname can be either
* a fixed name or a name template with '%d' for dynamic name allocation.
* in either case the final name for the bridge will be stored in @ifname
* and the associated file descriptor in @tapfd.
*
* Returns 0 in case of success or an errno code in case of failure.
*/
int
brAddTap(brControl *ctl,
const char *bridge,
char *ifname,
int maxlen,
int *tapfd)
{
int id, subst, fd;
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if (!ctl || !ctl->fd || !bridge || !ifname || !tapfd)
return EINVAL;
subst = id = 0;
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if (strstr(ifname, "%d"))
subst = 1;
if ((fd = open("/dev/net/tun", O_RDWR)) < 0)
return errno;
do {
struct ifreq try;
int len;
memset(&try, 0, sizeof(struct ifreq));
try.ifr_flags = IFF_TAP|IFF_NO_PI;
if (subst) {
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len = snprintf(try.ifr_name, maxlen, ifname, id);
if (len >= maxlen) {
errno = EADDRINUSE;
goto error;
}
} else {
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len = strlen(ifname);
if (len >= maxlen - 1) {
errno = EINVAL;
goto error;
}
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strncpy(try.ifr_name, ifname, len);
try.ifr_name[len] = '\0';
}
if (ioctl(fd, TUNSETIFF, &try) == 0) {
if ((errno = brAddInterface(ctl, bridge, try.ifr_name)))
goto error;
if ((errno = brSetInterfaceUp(ctl, try.ifr_name, 1)))
goto error;
if (ifname)
strncpy(ifname, try.ifr_name, maxlen);
*tapfd = fd;
return 0;
}
id++;
} while (subst && id <= MAX_BRIDGE_ID);
error:
close(fd);
return errno;
}
/**
* brSetInterfaceUp:
* @ctl: bridge control pointer
* @ifname: the interface name
* @up: 1 for up, 0 for down
*
* Function to control if an interface is activated (up, 1) or not (down, 0)
*
* Returns 0 in case of success or an errno code in case of failure.
*/
int
brSetInterfaceUp(brControl *ctl,
const char *ifname,
int up)
{
struct ifreq ifr;
int len;
int flags;
if (!ctl || !ifname)
return EINVAL;
if ((len = strlen(ifname)) >= BR_IFNAME_MAXLEN)
return EINVAL;
memset(&ifr, 0, sizeof(struct ifreq));
strncpy(ifr.ifr_name, ifname, len);
ifr.ifr_name[len] = '\0';
if (ioctl(ctl->fd, SIOCGIFFLAGS, &ifr) < 0)
return errno;
flags = up ? (ifr.ifr_flags | IFF_UP) : (ifr.ifr_flags & ~IFF_UP);
if (ifr.ifr_flags != flags) {
ifr.ifr_flags = flags;
if (ioctl(ctl->fd, SIOCSIFFLAGS, &ifr) < 0)
return errno;
}
return 0;
}
/**
* brGetInterfaceUp:
* @ctl: bridge control pointer
* @ifname: the interface name
* @up: where to store the status
*
* Function to query if an interface is activated (1) or not (0)
*
* Returns 0 in case of success or an errno code in case of failure.
*/
int
brGetInterfaceUp(brControl *ctl,
const char *ifname,
int *up)
{
struct ifreq ifr;
int len;
if (!ctl || !ifname || !up)
return EINVAL;
if ((len = strlen(ifname)) >= BR_IFNAME_MAXLEN)
return EINVAL;
memset(&ifr, 0, sizeof(struct ifreq));
strncpy(ifr.ifr_name, ifname, len);
ifr.ifr_name[len] = '\0';
if (ioctl(ctl->fd, SIOCGIFFLAGS, &ifr) < 0)
return errno;
*up = (ifr.ifr_flags & IFF_UP) ? 1 : 0;
return 0;
}
static int
brSetInetAddr(brControl *ctl,
const char *ifname,
int cmd,
const char *addr)
{
struct ifreq ifr;
struct in_addr inaddr;
int len, ret;
if (!ctl || !ctl->fd || !ifname || !addr)
return EINVAL;
if ((len = strlen(ifname)) >= BR_IFNAME_MAXLEN)
return EINVAL;
memset(&ifr, 0, sizeof(struct ifreq));
strncpy(ifr.ifr_name, ifname, len);
ifr.ifr_name[len] = '\0';
if ((ret = inet_pton(AF_INET, addr, &inaddr)) < 0)
return errno;
else if (ret == 0)
return EINVAL;
((struct sockaddr_in *)&ifr.ifr_data)->sin_family = AF_INET;
((struct sockaddr_in *)&ifr.ifr_data)->sin_addr = inaddr;
if (ioctl(ctl->fd, cmd, &ifr) < 0)
return errno;
return 0;
}
static int
brGetInetAddr(brControl *ctl,
const char *ifname,
int cmd,
char *addr,
int maxlen)
{
struct ifreq ifr;
struct in_addr *inaddr;
int len;
if (!ctl || !ctl->fd || !ifname || !addr)
return EINVAL;
if ((len = strlen(ifname)) >= BR_IFNAME_MAXLEN)
return EINVAL;
memset(&ifr, 0, sizeof(struct ifreq));
strncpy(ifr.ifr_name, ifname, len);
ifr.ifr_name[len] = '\0';
if (ioctl(ctl->fd, cmd, &ifr) < 0)
return errno;
if (maxlen < BR_INET_ADDR_MAXLEN || ifr.ifr_addr.sa_family != AF_INET)
return EFAULT;
inaddr = &((struct sockaddr_in *)&ifr.ifr_data)->sin_addr;
if (!inet_ntop(AF_INET, inaddr, addr, maxlen))
return errno;
return 0;
}
/**
* brSetInetAddress:
* @ctl: bridge control pointer
* @ifname: the interface name
* @addr: the string representation of the IP address
*
* Function to bind the interface to an IP address, it should handle
* IPV4 and IPv6. The string for addr would be of the form
* "ddd.ddd.ddd.ddd" assuming the common IPv4 format.
*
* Returns 0 in case of success or an errno code in case of failure.
*/
int
brSetInetAddress(brControl *ctl,
const char *ifname,
const char *addr)
{
return brSetInetAddr(ctl, ifname, SIOCSIFADDR, addr);
}
/**
* brGetInetAddress:
* @ctl: bridge control pointer
* @ifname: the interface name
* @addr: the array for the string representation of the IP address
* @maxlen: size of @addr in bytes
*
* Function to get the IP address of an interface, it should handle
* IPV4 and IPv6. The returned string for addr would be of the form
* "ddd.ddd.ddd.ddd" assuming the common IPv4 format.
*
* Returns 0 in case of success or an errno code in case of failure.
*/
int
brGetInetAddress(brControl *ctl,
const char *ifname,
char *addr,
int maxlen)
{
return brGetInetAddr(ctl, ifname, SIOCGIFADDR, addr, maxlen);
}
/**
* brSetInetNetmask:
* @ctl: bridge control pointer
* @ifname: the interface name
* @addr: the string representation of the netmask
*
* Function to set the netmask of an interface, it should handle
* IPV4 and IPv6 forms. The string for addr would be of the form
* "ddd.ddd.ddd.ddd" assuming the common IPv4 format.
*
* Returns 0 in case of success or an errno code in case of failure.
*/
int
brSetInetNetmask(brControl *ctl,
const char *ifname,
const char *addr)
{
return brSetInetAddr(ctl, ifname, SIOCSIFNETMASK, addr);
}
/**
* brGetInetNetmask:
* @ctl: bridge control pointer
* @ifname: the interface name
* @addr: the array for the string representation of the netmask
* @maxlen: size of @addr in bytes
*
* Function to get the netmask of an interface, it should handle
* IPV4 and IPv6. The returned string for addr would be of the form
* "ddd.ddd.ddd.ddd" assuming the common IPv4 format.
*
* Returns 0 in case of success or an errno code in case of failure.
*/
int
brGetInetNetmask(brControl *ctl,
const char *ifname,
char *addr,
int maxlen)
{
return brGetInetAddr(ctl, ifname, SIOCGIFNETMASK, addr, maxlen);
}
static int
brctlSpawn(char * const *argv)
{
pid_t pid, ret;
int status;
int null = -1;
if ((null = open(_PATH_DEVNULL, O_RDONLY)) < 0)
return errno;
pid = fork();
if (pid == -1) {
int saved_errno = errno;
close(null);
return saved_errno;
}
if (pid == 0) { /* child */
dup2(null, STDIN_FILENO);
dup2(null, STDOUT_FILENO);
dup2(null, STDERR_FILENO);
close(null);
execvp(argv[0], argv);
_exit (1);
}
close(null);
while ((ret = waitpid(pid, &status, 0) == -1) && errno == EINTR);
if (ret == -1)
return errno;
return (WIFEXITED(status) && WEXITSTATUS(status) == 0) ? 0 : EINVAL;
}
/**
* brSetForwardDelay:
* @ctl: bridge control pointer
* @bridge: the bridge name
* @delay: delay in seconds
*
* Set the bridge forward delay
*
* Returns 0 in case of success or an errno code in case of failure.
*/
int
brSetForwardDelay(brControl *ctl ATTRIBUTE_UNUSED,
const char *bridge,
int delay)
{
char **argv;
int retval = ENOMEM;
int n;
char delayStr[30];
n = 1 + /* brctl */
1 + /* setfd */
1 + /* brige name */
1; /* value */
snprintf(delayStr, sizeof(delayStr), "%d", delay);
if (!(argv = calloc(n + 1, sizeof(*argv))))
goto error;
n = 0;
if (!(argv[n++] = strdup(BRCTL)))
goto error;
if (!(argv[n++] = strdup("setfd")))
goto error;
if (!(argv[n++] = strdup(bridge)))
goto error;
if (!(argv[n++] = strdup(delayStr)))
goto error;
argv[n++] = NULL;
retval = brctlSpawn(argv);
error:
if (argv) {
n = 0;
while (argv[n])
free(argv[n++]);
free(argv);
}
return retval;
}
/**
* brSetEnableSTP:
* @ctl: bridge control pointer
* @bridge: the bridge name
* @enable: 1 to enable, 0 to disable
*
* Control whether the bridge participates in the spanning tree protocol,
* in general don't disable it without good reasons.
*
* Returns 0 in case of success or an errno code in case of failure.
*/
int
brSetEnableSTP(brControl *ctl ATTRIBUTE_UNUSED,
const char *bridge,
int enable)
{
char **argv;
int retval = ENOMEM;
int n;
n = 1 + /* brctl */
1 + /* stp */
1 + /* brige name */
1; /* value */
if (!(argv = calloc(n + 1, sizeof(*argv))))
goto error;
n = 0;
if (!(argv[n++] = strdup(BRCTL)))
goto error;
if (!(argv[n++] = strdup("stp")))
goto error;
if (!(argv[n++] = strdup(bridge)))
goto error;
if (!(argv[n++] = strdup(enable ? "on" : "off")))
goto error;
argv[n++] = NULL;
retval = brctlSpawn(argv);
error:
if (argv) {
n = 0;
while (argv[n])
free(argv[n++]);
free(argv);
}
return retval;
}
#endif /* WITH_QEMU */