[libvirt] [PATCHv3 2/9] util: functions to manage bridge fdb (forwarding database)
Laine Stump
laine at laine.org
Mon Dec 8 16:00:02 UTC 2014
These two functions use netlink RTM_NEWNEIGH and RTM_DELNEIGH messages
to add and delete entries from a bridge's fdb. The bridge itself is
not referenced in the arguments to the functions, only the name of the
device that is attached to the bridge (since a device can only be
attached to one bridge at a time, and must be attached for this
function to make sense, the kernel easily infers which bridge's fdb is
being modified by looking at the device name/index).
---
No change from V2.
src/libvirt_private.syms | 2 +
src/util/virnetdevbridge.c | 147 +++++++++++++++++++++++++++++++++++++++++++++
src/util/virnetdevbridge.h | 16 +++++
3 files changed, 165 insertions(+)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 7cb57a9..3e445fc 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1661,6 +1661,8 @@ virNetDevBandwidthUpdateRate;
virNetDevBridgeAddPort;
virNetDevBridgeCreate;
virNetDevBridgeDelete;
+virNetDevBridgeFDBAdd;
+virNetDevBridgeFDBDel;
virNetDevBridgeGetSTP;
virNetDevBridgeGetSTPDelay;
virNetDevBridgeGetVlanFiltering;
diff --git a/src/util/virnetdevbridge.c b/src/util/virnetdevbridge.c
index c6a3e8e..78c4a25 100644
--- a/src/util/virnetdevbridge.c
+++ b/src/util/virnetdevbridge.c
@@ -37,6 +37,9 @@
#include <netinet/in.h>
#ifdef __linux__
+# if defined(HAVE_LIBNL)
+# include "virnetlink.h"
+# endif
# include <linux/sockios.h>
# include <linux/param.h> /* HZ */
# if NETINET_LINUX_WORKAROUND
@@ -913,3 +916,147 @@ virNetDevBridgeSetVlanFiltering(const char *brname ATTRIBUTE_UNUSED,
return -1;
}
#endif
+
+
+#if defined(__linux__) && defined(HAVE_LIBNL)
+/* virNetDevBridgeFDBAddDel:
+ * @mac: the MAC address being added to the table
+ * @ifname: name of the port (interface) of the bridge that wants this MAC
+ * @flags: any of virNetDevBridgeFDBFlags ORed together.
+ * @isAdd: true if adding the entry, fals if deleting
+ *
+ * Use netlink RTM_NEWNEIGH and RTM_DELNEIGH messages to add and
+ * delete entries from a bridge's fdb. The bridge itself is not
+ * referenced in the arguments to the function, only the name of the
+ * device that is attached to the bridge (since a device can only be
+ * attached to one bridge at a time, and must be attached for this
+ * function to make sense, the kernel easily infers which bridge's fdb
+ * is being modified by looking at the device name/index).
+ *
+ * Attempting to add an existing entry, or delete a non-existing entry
+ * *is* an error.
+ *
+ * returns 0 on success, -1 on failure.
+ */
+static int
+virNetDevBridgeFDBAddDel(const virMacAddr *mac, const char *ifname,
+ unsigned int flags, bool isAdd)
+{
+ int ret = -1;
+ struct nlmsghdr *resp = NULL;
+ struct nlmsgerr *err;
+ unsigned int recvbuflen;
+ struct nl_msg *nl_msg;
+ struct ndmsg ndm = { .ndm_family = PF_BRIDGE, .ndm_state = NUD_NOARP };
+
+ if (virNetDevGetIndex(ifname, &ndm.ndm_ifindex) < 0)
+ return -1;
+
+ if (flags & VIR_NETDEVBRIDGE_FDB_FLAG_ROUTER)
+ ndm.ndm_flags |= NTF_ROUTER;
+ if (flags & VIR_NETDEVBRIDGE_FDB_FLAG_SELF)
+ ndm.ndm_flags |= NTF_SELF;
+ if (flags & VIR_NETDEVBRIDGE_FDB_FLAG_MASTER)
+ ndm.ndm_flags |= NTF_MASTER;
+ /* default self (same as iproute2's bridge command */
+ if (!(ndm.ndm_flags & (NTF_MASTER | NTF_SELF)))
+ ndm.ndm_flags |= NTF_SELF;
+
+ if (flags & VIR_NETDEVBRIDGE_FDB_FLAG_PERMANENT)
+ ndm.ndm_state |= NUD_PERMANENT;
+ if (flags & VIR_NETDEVBRIDGE_FDB_FLAG_TEMP)
+ ndm.ndm_state |= NUD_REACHABLE;
+ /* default permanent, same as iproute2's bridge command */
+ if (!(ndm.ndm_state & (NUD_PERMANENT | NUD_REACHABLE)))
+ ndm.ndm_state |= NUD_PERMANENT;
+
+ nl_msg = nlmsg_alloc_simple(isAdd ? RTM_NEWNEIGH : RTM_DELNEIGH,
+ NLM_F_REQUEST |
+ (isAdd ? (NLM_F_CREATE | NLM_F_EXCL) : 0));
+ if (!nl_msg) {
+ virReportOOMError();
+ return -1;
+ }
+
+ if (nlmsg_append(nl_msg, &ndm, sizeof(ndm), NLMSG_ALIGNTO) < 0)
+ goto buffer_too_small;
+ if (nla_put(nl_msg, NDA_LLADDR, VIR_MAC_BUFLEN, mac) < 0)
+ goto buffer_too_small;
+
+ /* NB: this message can also accept a Destination IP, a port, a
+ * vlan tag, and a via (see iproute2/bridge/fdb.c:fdb_modify()),
+ * but those aren't required for our application
+ */
+
+ if (virNetlinkCommand(nl_msg, &resp, &recvbuflen, 0, 0,
+ NETLINK_ROUTE, 0) < 0) {
+ goto cleanup;
+ }
+ if (recvbuflen < NLMSG_LENGTH(0) || resp == NULL)
+ goto malformed_resp;
+
+ switch (resp->nlmsg_type) {
+ case NLMSG_ERROR:
+ err = (struct nlmsgerr *)NLMSG_DATA(resp);
+ if (resp->nlmsg_len < NLMSG_LENGTH(sizeof(*err)))
+ goto malformed_resp;
+ if (err->error) {
+ virReportSystemError(-err->error,
+ _("error adding fdb entry for %s"), ifname);
+ goto cleanup;
+ }
+ break;
+ case NLMSG_DONE:
+ break;
+
+ default:
+ goto malformed_resp;
+ }
+
+ ret = 0;
+ cleanup:
+ nlmsg_free(nl_msg);
+ VIR_FREE(resp);
+ return ret;
+
+ malformed_resp:
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("malformed netlink response message"));
+ goto cleanup;
+
+ buffer_too_small:
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("allocated netlink buffer is too small"));
+ goto cleanup;
+}
+
+
+#else
+static int
+virNetDevBridgeFDBAddDel(const virMacAddr *mac ATTRIBUTE_UNUSED,
+ const char *ifname ATTRIBUTE_UNUSED,
+ unsigned int fdbFlags ATTRIBUTE_UNUSED,
+ bool isAdd ATTRIBUTE_UNUSED)
+{
+ virReportSystemError(ENOSYS, "%s",
+ _("Unable to add/delete fdb entries on this platform"));
+ return -1;
+}
+
+
+#endif
+
+int
+virNetDevBridgeFDBAdd(const virMacAddr *mac, const char *ifname,
+ unsigned int flags)
+{
+ return virNetDevBridgeFDBAddDel(mac, ifname, flags, true);
+}
+
+
+int
+virNetDevBridgeFDBDel(const virMacAddr *mac, const char *ifname,
+ unsigned int flags)
+{
+ return virNetDevBridgeFDBAddDel(mac, ifname, flags, false);
+}
diff --git a/src/util/virnetdevbridge.h b/src/util/virnetdevbridge.h
index 8188a2f..141f231 100644
--- a/src/util/virnetdevbridge.h
+++ b/src/util/virnetdevbridge.h
@@ -24,6 +24,7 @@
# define __VIR_NETDEV_BRIDGE_H__
# include "internal.h"
+# include "virmacaddr.h"
int virNetDevBridgeCreate(const char *brname)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_RETURN_CHECK;
@@ -77,4 +78,19 @@ int virNetDevBridgePortSetUnicastFlood(const char *brname,
bool enable)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
+typedef enum {
+ VIR_NETDEVBRIDGE_FDB_FLAG_ROUTER = (1 << 0),
+ VIR_NETDEVBRIDGE_FDB_FLAG_SELF = (1 << 1),
+ VIR_NETDEVBRIDGE_FDB_FLAG_MASTER = (1 << 2),
+
+ VIR_NETDEVBRIDGE_FDB_FLAG_PERMANENT = (1 << 3),
+ VIR_NETDEVBRIDGE_FDB_FLAG_TEMP = (1 << 4),
+} virNetDevBridgeFDBFlags;
+
+int virNetDevBridgeFDBAdd(const virMacAddr *mac, const char *ifname,
+ unsigned int flags)
+ ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
+int virNetDevBridgeFDBDel(const virMacAddr *mac, const char *ifname,
+ unsigned int flags)
+ ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
#endif /* __VIR_NETDEV_BRIDGE_H__ */
--
1.9.3
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