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netdevtap: Use common helper function to create unique tap name
Simplify GenerateName/ReserveName for netdevtap by using common functions. Signed-off-by: Shi Lei <shi_lei@massclouds.com> Reviewed-by: Laine Stump <laine@redhat.com>
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@ -2692,7 +2692,6 @@ virNetDevTapGetName;
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virNetDevTapGetRealDeviceName;
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virNetDevTapInterfaceStats;
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virNetDevTapReattachBridge;
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virNetDevTapReserveName;
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# util/virnetdevveth.h
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@ -3396,7 +3396,7 @@ qemuProcessNotifyNets(virDomainDefPtr def)
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case VIR_DOMAIN_NET_TYPE_BRIDGE:
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case VIR_DOMAIN_NET_TYPE_NETWORK:
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case VIR_DOMAIN_NET_TYPE_ETHERNET:
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virNetDevTapReserveName(net->ifname);
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virNetDevReserveName(net->ifname);
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break;
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case VIR_DOMAIN_NET_TYPE_USER:
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case VIR_DOMAIN_NET_TYPE_VHOSTUSER:
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@ -49,51 +49,11 @@
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#if defined(WITH_GETIFADDRS) && defined(AF_LINK)
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# include <ifaddrs.h>
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#endif
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#include <math.h>
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#define VIR_FROM_THIS VIR_FROM_NONE
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VIR_LOG_INIT("util.netdevtap");
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virMutex virNetDevTapCreateMutex = VIR_MUTEX_INITIALIZER;
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static int virNetDevTapLastID = -1; /* not "unsigned" because callers use %d */
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/**
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* virNetDevTapReserveName:
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* @name: name of an existing tap device
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*
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* Set the value of virNetDevTapLastID to assure that any new tap
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* device created with an autogenerated name will use a number higher
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* than the number in the given tap device name.
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*
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* Returns nothing.
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*/
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void
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virNetDevTapReserveName(const char *name)
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{
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unsigned int id;
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const char *idstr = NULL;
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if (STRPREFIX(name, VIR_NET_GENERATED_VNET_PREFIX)) {
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VIR_INFO("marking device in use: '%s'", name);
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idstr = name + strlen(VIR_NET_GENERATED_VNET_PREFIX);
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if (virStrToLong_ui(idstr, NULL, 10, &id) >= 0) {
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virMutexLock(&virNetDevTapCreateMutex);
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if (virNetDevTapLastID < (int)id)
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virNetDevTapLastID = id;
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virMutexUnlock(&virNetDevTapCreateMutex);
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}
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}
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}
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/**
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* virNetDevTapGetName:
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* @tapfd: a tun/tap file descriptor
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@ -183,55 +143,6 @@ virNetDevTapGetRealDeviceName(char *ifname G_GNUC_UNUSED)
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#ifdef TUNSETIFF
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/**
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* virNetDevTapGenerateName:
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* @ifname: pointer to pointer to string containing template
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*
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* generate a new (currently unused) name for a new tap device based
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* on the templace string in @ifname - replace %d with
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* ++virNetDevTapLastID, and keep trying new values until one is found
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* that doesn't already exist, or we've tried 10000 different
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* names. Once a usable name is found, replace the template with the
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* actual name.
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*
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* Returns 0 on success, -1 on failure.
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*/
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static int
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virNetDevTapGenerateName(char **ifname)
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{
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int id;
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double maxIDd = pow(10, IFNAMSIZ - 1 - strlen(VIR_NET_GENERATED_VNET_PREFIX));
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int maxID = INT_MAX;
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int attempts = 0;
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if (maxIDd <= (double)INT_MAX)
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maxID = (int)maxIDd;
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do {
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g_autofree char *try = NULL;
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id = ++virNetDevTapLastID;
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/* reset before overflow */
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if (virNetDevTapLastID >= maxID)
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virNetDevTapLastID = -1;
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try = g_strdup_printf(*ifname, id);
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if (!virNetDevExists(try)) {
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g_free(*ifname);
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*ifname = g_steal_pointer(&try);
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return 0;
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}
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} while (++attempts < 10000);
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virReportError(VIR_ERR_INTERNAL_ERROR,
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_("no unused %s names available"),
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VIR_NET_GENERATED_VNET_PREFIX);
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return -1;
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}
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/**
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* virNetDevTapCreate:
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* @ifname: the interface name
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@ -263,16 +174,14 @@ int virNetDevTapCreate(char **ifname,
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int ret = -1;
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int fd = -1;
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virMutexLock(&virNetDevTapCreateMutex);
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/* if ifname is "vnet%d", then auto-generate a name for the new
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* device (the kernel could do this for us, but has a bad habit of
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* immediately re-using names that have just been released, which
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* can lead to race conditions).
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*/
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if (STREQ(*ifname, VIR_NET_GENERATED_VNET_PREFIX "%d") &&
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virNetDevTapGenerateName(ifname) < 0) {
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goto cleanup;
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* if ifname is just a user-provided name, virNetDevGenerateName
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* leaves it unchanged. */
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if (virNetDevGenerateName(ifname, VIR_NET_DEV_GEN_NAME_VNET) < 0) {
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return -1;
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}
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if (!tunpath)
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@ -333,7 +242,6 @@ int virNetDevTapCreate(char **ifname,
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ret = 0;
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cleanup:
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virMutexUnlock(&virNetDevTapCreateMutex);
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if (ret < 0) {
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VIR_FORCE_CLOSE(fd);
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while (i--)
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@ -29,10 +29,6 @@
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# define VIR_NETDEV_TAP_REQUIRE_MANUAL_CLEANUP 1
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#endif
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void
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virNetDevTapReserveName(const char *name)
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ATTRIBUTE_NONNULL(1);
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int virNetDevTapCreate(char **ifname,
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const char *tunpath,
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int *tapfd,
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