[libvirt] [PATCH] Remove MAX_TAP_ID, take 2
(Sorry, my first posting included some gnulib droppings in the
patch. This removes that, everything else is the same.)
As far as I can tell, there's no reason to format the device string in
brAddTap(). Delegate the job to TUNSETIFF, thereby removing the loop
and the MAX_TAP_ID artificial limit. This patch allows me to get
421 guests running before hitting other limits.
Signed-off-by: Aron Griffis <aron.griffis(a)hp.com>
---
src/bridge.c | 94 +++++++++++++++++++++-------------------------------------
1 files changed, 34 insertions(+), 60 deletions(-)
diff --git a/src/bridge.c b/src/bridge.c
index 0509afd..ec37192 100644
--- a/src/bridge.c
+++ b/src/bridge.c
@@ -49,8 +49,6 @@
#include "util.h"
#include "logging.h"
-#define MAX_TAP_ID 256
-
#define JIFFIES_TO_MS(j) (((j)*1000)/HZ)
#define MS_TO_JIFFIES(ms) (((ms)*HZ)/1000)
@@ -466,76 +464,52 @@ brAddTap(brControl *ctl,
int vnet_hdr,
int *tapfd)
{
- int id, subst, fd;
+ int fd, len;
+ struct ifreq ifr = {0};
if (!ctl || !ctl->fd || !bridge || !ifname)
return EINVAL;
- subst = id = 0;
-
- if (strstr(*ifname, "%d"))
- subst = 1;
-
if ((fd = open("/dev/net/tun", O_RDWR)) < 0)
return errno;
- if (vnet_hdr)
- vnet_hdr = brProbeVnetHdr(fd);
+ ifr.ifr_flags = IFF_TAP|IFF_NO_PI;
- do {
- struct ifreq try;
- int len;
+#ifdef IFF_VNET_HDR
+ if (vnet_hdr && brProbeVnetHdr(fd))
+ ifr.ifr_flags |= IFF_VNET_HDR;
+#endif
- memset(&try, 0, sizeof(struct ifreq));
+ strncpy(ifr.ifr_name, *ifname, IFNAMSIZ-1);
- try.ifr_flags = IFF_TAP|IFF_NO_PI;
+ if (ioctl(fd, TUNSETIFF, &ifr) < 0)
+ goto error;
-#ifdef IFF_VNET_HDR
- if (vnet_hdr)
- try.ifr_flags |= IFF_VNET_HDR;
-#endif
+ len = strlen(ifr.ifr_name);
+ if (len >= BR_IFNAME_MAXLEN - 1) {
+ errno = EINVAL;
+ goto error;
+ }
- if (subst) {
- len = snprintf(try.ifr_name, BR_IFNAME_MAXLEN, *ifname, id);
- if (len >= BR_IFNAME_MAXLEN) {
- errno = EADDRINUSE;
- goto error;
- }
- } else {
- len = strlen(*ifname);
- if (len >= BR_IFNAME_MAXLEN - 1) {
- errno = EINVAL;
- goto error;
- }
-
- strncpy(try.ifr_name, *ifname, len);
- try.ifr_name[len] = '\0';
- }
-
- if (ioctl(fd, TUNSETIFF, &try) == 0) {
- /* We need to set the interface MTU before adding it
- * to the bridge, because the bridge will have its
- * MTU adjusted automatically when we add the new interface.
- */
- if ((errno = brSetInterfaceMtu(ctl, bridge, try.ifr_name)))
- goto error;
- if ((errno = brAddInterface(ctl, bridge, try.ifr_name)))
- goto error;
- if ((errno = brSetInterfaceUp(ctl, try.ifr_name, 1)))
- goto error;
- if (!tapfd &&
- (errno = ioctl(fd, TUNSETPERSIST, 1)))
- goto error;
- VIR_FREE(*ifname);
- if (!(*ifname = strdup(try.ifr_name)))
- goto error;
- if (tapfd)
- *tapfd = fd;
- return 0;
- }
-
- id++;
- } while (subst && id <= MAX_TAP_ID);
+ /* We need to set the interface MTU before adding it
+ * to the bridge, because the bridge will have its
+ * MTU adjusted automatically when we add the new interface.
+ */
+ if ((errno = brSetInterfaceMtu(ctl, bridge, ifr.ifr_name)))
+ goto error;
+ if ((errno = brAddInterface(ctl, bridge, ifr.ifr_name)))
+ goto error;
+ if ((errno = brSetInterfaceUp(ctl, ifr.ifr_name, 1)))
+ goto error;
+ if (!tapfd &&
+ (errno = ioctl(fd, TUNSETPERSIST, 1)))
+ goto error;
+ VIR_FREE(*ifname);
+ if (!(*ifname = strdup(ifr.ifr_name)))
+ goto error;
+ if (tapfd)
+ *tapfd = fd;
+ return 0;
error:
close(fd);