[PATCHv2 1/2] util: Functions to update host network device's multicast filter

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From: Tony Krowiak <akrowiak@xxxxxxxxxxxxxxxxxx>

This patch provides the utility functions to needed to synchronize the
changes made to a guest domain network device's multicast filter
with the corresponding macvtap device's filter on the host:

* Get/add/remove multicast MAC addresses
* Get the macvtap device's RX filter list

changes from v1:
* Using virHexToBin function to parse HEX MAC address instead of
  sscanf in virMacAddrParseHex function
* Using ENOSYS in error messages for empty functions
* Reading entire file with virFileReadAll function when
  parsing /proc/net/dev_mcast file
* Using VIR_APPEND_ELEMENT macro when appending array of
  /proc/net/dev_mcast file objects
* Misc. formatting changes

Signed-off-by: Tony Krowiak <akrowiak@xxxxxxxxxxxxxxxxxx>
---
 src/libvirt_private.syms |    4 +
 src/util/virmacaddr.c    |   25 ++++
 src/util/virmacaddr.h    |    4 +
 src/util/virnetdev.c     |  358 ++++++++++++++++++++++++++++++++++++++++++++++
 src/util/virnetdev.h     |   10 ++
 5 files changed, 401 insertions(+), 0 deletions(-)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index d6265ac..6d06a2c 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1590,13 +1590,16 @@ virMacAddrIsBroadcastRaw;
 virMacAddrIsMulticast;
 virMacAddrIsUnicast;
 virMacAddrParse;
+virMacAddrParseHex;
 virMacAddrSet;
 virMacAddrSetRaw;
 
 
 # util/virnetdev.h
+virNetDevAddMulti;
 virNetDevAddRoute;
 virNetDevClearIPv4Address;
+virNetDevDelMulti;
 virNetDevExists;
 virNetDevGetIndex;
 virNetDevGetIPv4Address;
@@ -1604,6 +1607,7 @@ virNetDevGetLinkInfo;
 virNetDevGetMAC;
 virNetDevGetMTU;
 virNetDevGetPhysicalFunction;
+virNetDevGetRxFilter;
 virNetDevGetVirtualFunctionIndex;
 virNetDevGetVirtualFunctionInfo;
 virNetDevGetVirtualFunctions;
diff --git a/src/util/virmacaddr.c b/src/util/virmacaddr.c
index ebd1182..612a409 100644
--- a/src/util/virmacaddr.c
+++ b/src/util/virmacaddr.c
@@ -29,6 +29,7 @@
 #include "c-ctype.h"
 #include "virmacaddr.h"
 #include "virrandom.h"
+#include "virutil.h"
 
 static const unsigned char virMacAddrBroadcastAddrRaw[VIR_MAC_BUFLEN] =
     { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
@@ -198,6 +199,30 @@ virMacAddrFormat(const virMacAddr *addr,
     return str;
 }
 
+/**
+ * virMacAddrParseHex:
+ * @str: string hexadecimal representation of MAC address, e.g., "F801EFCE3aCB"
+ * @addr: 6-byte MAC address
+ *
+ * Parse the hexadecimal representation of a MAC address
+ *
+ * Return 0 upon success, or -1 in case of error.
+ */
+int
+virMacAddrParseHex(const char *str, virMacAddrPtr addr)
+{
+    size_t i;
+
+    if (strspn(str, "0123456789abcdefABCDEF") != VIR_MAC_HEXLEN ||
+        str[VIR_MAC_HEXLEN])
+        return -1;
+
+    for (i = 0; i < VIR_MAC_BUFLEN; i++)
+        addr->addr[i] = (virHexToBin(str[2 * i]) << 4 |
+                         virHexToBin(str[2 * i + 1]));
+    return 0;
+}
+
 void virMacAddrGenerate(const unsigned char prefix[VIR_MAC_PREFIX_BUFLEN],
                         virMacAddrPtr addr)
 {
diff --git a/src/util/virmacaddr.h b/src/util/virmacaddr.h
index 49efc36..72a285a 100644
--- a/src/util/virmacaddr.h
+++ b/src/util/virmacaddr.h
@@ -27,6 +27,7 @@
 # include "internal.h"
 
 # define VIR_MAC_BUFLEN 6
+#define VIR_MAC_HEXLEN (VIR_MAC_BUFLEN * 2)
 # define VIR_MAC_PREFIX_BUFLEN 3
 # define VIR_MAC_STRING_BUFLEN (VIR_MAC_BUFLEN * 3)
 
@@ -50,6 +51,9 @@ void virMacAddrGenerate(const unsigned char prefix[VIR_MAC_PREFIX_BUFLEN],
                         virMacAddrPtr addr);
 int virMacAddrParse(const char* str,
                     virMacAddrPtr addr) ATTRIBUTE_RETURN_CHECK;
+int virMacAddrParseHex(const char* str,
+                       virMacAddrPtr addr)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
 bool virMacAddrIsUnicast(const virMacAddr *addr);
 bool virMacAddrIsMulticast(const virMacAddr *addr);
 bool virMacAddrIsBroadcastRaw(const unsigned char s[VIR_MAC_BUFLEN]);
diff --git a/src/util/virnetdev.c b/src/util/virnetdev.c
index db5623a..1410cfe 100644
--- a/src/util/virnetdev.c
+++ b/src/util/virnetdev.c
@@ -56,6 +56,35 @@
 
 VIR_LOG_INIT("util.netdev");
 
+# define PROC_NET_DEV_MCAST "/proc/net/dev_mcast"
+# define MAX_MCAST_SIZE 50*14336
+# define VIR_MCAST_NAME_LEN (IFNAMSIZ + 1)
+# define VIR_MCAST_INDEX_TOKEN_IDX 0
+# define VIR_MCAST_NAME_TOKEN_IDX 1
+# define VIR_MCAST_USERS_TOKEN_IDX 2
+# define VIR_MCAST_GLOBAL_TOKEN_IDX 3
+# define VIR_MCAST_ADDR_TOKEN_IDX 4
+# define VIR_MCAST_NUM_TOKENS 5
+# define VIR_MCAST_TOKEN_DELIMS " \n"
+# define VIR_MCAST_ADDR_LEN (VIR_MAC_HEXLEN + 1)
+
+typedef struct _virNetDevMcastEntry virNetDevMcastEntry;
+typedef virNetDevMcastEntry *virNetDevMcastEntryPtr;
+struct _virNetDevMcastEntry  {
+        int index;
+        char name[VIR_MCAST_NAME_LEN];
+        int users;
+        bool global;
+        virMacAddr macaddr;
+};
+
+typedef struct _virNetDevMcast virNetDevMcast;
+typedef virNetDevMcast *virNetDevMcastPtr;
+struct _virNetDevMcast {
+    size_t nentries;
+    virNetDevMcastEntryPtr *entries;
+};
+
 #if defined(HAVE_STRUCT_IFREQ)
 static int virNetDevSetupControlFull(const char *ifname,
                                      struct ifreq *ifr,
@@ -1934,6 +1963,266 @@ virNetDevGetLinkInfo(const char *ifname,
 #endif /* defined(__linux__) */
 
 
+#if defined(SIOCADDMULTI) && defined(HAVE_STRUCT_IFREQ)
+/**
+ * virNetDevAddMulti:
+ * @ifname: interface name to which to add multicast MAC address
+ * @macaddr: MAC address
+ *
+ * This function adds the @macaddr to the multicast list for a given interface
+ * @ifname.
+ *
+ * Returns 0 in case of success or -1 on failure
+ */
+int virNetDevAddMulti(const char *ifname,
+                      virMacAddrPtr macaddr)
+{
+    int fd = -1;
+    int ret = -1;
+    struct ifreq ifr;
+
+    if ((fd = virNetDevSetupControl(ifname, &ifr)) < 0)
+        return -1;
+
+    ifr.ifr_hwaddr.sa_family = AF_UNSPEC;
+    virMacAddrGetRaw(macaddr, (unsigned char *)ifr.ifr_hwaddr.sa_data);
+
+    if (ioctl(fd, SIOCADDMULTI, &ifr) < 0) {
+        char macstr[VIR_MAC_STRING_BUFLEN];
+        virReportSystemError(errno,
+                             _("Cannot add multicast MAC %s on '%s' interface"),
+                             virMacAddrFormat(macaddr, macstr), ifname);
+        goto cleanup;
+    }
+
+    ret = 0;
+
+ cleanup:
+    VIR_FORCE_CLOSE(fd);
+    return ret;
+}
+#else
+int virNetDevAddMulti(const char *ifname,
+                      virMacAddrPtr macaddr ATTRIBUTE_UNUSED)
+{
+    char macstr[VIR_MAC_STRING_BUFLEN];
+    virReportSystemError(ENOSYS,
+                         _("Cannot add multicast MAC %s on '%s' interface"),
+                         virMacAddrFormat(macaddr, macstr), ifname);
+    return -1;
+}
+#endif
+
+#if defined(SIOCDELMULTI) && defined(HAVE_STRUCT_IFREQ)
+/**
+ * virNetDevDelMulti:
+ * @ifname: interface name from which to delete the multicast MAC address
+ * @macaddr: MAC address
+ *
+ * This function deletes the @macaddr from the multicast list for a given
+ * interface @ifname.
+ *
+ * Returns 0 in case of success or -1 on failure
+ */
+int virNetDevDelMulti(const char *ifname,
+                      virMacAddrPtr macaddr)
+{
+    int fd = -1;
+    int ret = -1;
+    struct ifreq ifr;
+
+    if ((fd = virNetDevSetupControl(ifname, &ifr)) < 0)
+        return -1;
+
+    ifr.ifr_hwaddr.sa_family = AF_UNSPEC;
+    virMacAddrGetRaw(macaddr, (unsigned char *)ifr.ifr_hwaddr.sa_data);
+
+    if (ioctl(fd, SIOCDELMULTI, &ifr) < 0) {
+        char macstr[VIR_MAC_STRING_BUFLEN];
+        virReportSystemError(errno,
+                             _("Cannot add multicast MAC %s on '%s' interface"),
+                             virMacAddrFormat(macaddr, macstr), ifname);
+        goto cleanup;
+    }
+
+    ret = 0;
+
+ cleanup:
+    VIR_FORCE_CLOSE(fd);
+    return ret;
+}
+#else
+int virNetDevDelMulti(const char *ifname,
+                      virMacAddrPtr macaddr ATTRIBUTE_UNUSED)
+{
+    char macstr[VIR_MAC_STRING_BUFLEN];
+    virReportSystemError(ENOSYS,
+                         _("Cannot delete multicast MAC %s on '%s' interface"),
+                         virMacAddrFormat(macaddr, macstr), ifname);
+    return -1;
+}
+#endif
+
+static int virNetDevParseMcast(char *buf, virNetDevMcastEntryPtr mcast)
+{
+    int ifindex;
+    int num;
+    char *next;
+    char *token;
+    char *saveptr;
+    char *endptr;
+
+    for (ifindex = 0, next = buf; ifindex < VIR_MCAST_NUM_TOKENS; ifindex++,
+         next = NULL) {
+        token = strtok_r(next, VIR_MCAST_TOKEN_DELIMS, &saveptr);
+
+        if (token == NULL) {
+            virReportSystemError(EINVAL,
+                                 _("failed to parse multicast address from '%s'"),
+                                 buf);
+            return -1;
+        }
+
+        switch (ifindex) {
+            case VIR_MCAST_INDEX_TOKEN_IDX:
+                if (virStrToLong_i(token, &endptr, 10, &num) < 0) {
+                    virReportSystemError(EINVAL,
+                                         _("Failed to parse interface index from '%s'"),
+                                         buf);
+                    return -1;
+
+                }
+
+                mcast->index = num;
+
+                break;
+            case VIR_MCAST_NAME_TOKEN_IDX:
+                if (virStrncpy(mcast->name, token, strlen(token),
+                    VIR_MCAST_NAME_LEN) == NULL) {
+                    virReportSystemError(EINVAL,
+                                         _("Failed to parse network device name from '%s'"),
+                                         buf);
+                    return -1;
+                }
+
+                break;
+            case VIR_MCAST_USERS_TOKEN_IDX:
+                if (virStrToLong_i(token, &endptr, 10, &num) < 0) {
+                    virReportSystemError(EINVAL,
+                                         _("Failed to parse users from '%s'"),
+                                         buf);
+                    return -1;
+
+                }
+
+                mcast->users = num;
+
+                break;
+            case VIR_MCAST_GLOBAL_TOKEN_IDX:
+                if (virStrToLong_i(token, &endptr, 10, &num) < 0) {
+                    virReportSystemError(EINVAL,
+                                         _("Failed to parse users from '%s'"),
+                                         buf);
+                    return -1;
+
+                }
+
+                mcast->global = num;
+
+                break;
+            case VIR_MCAST_ADDR_TOKEN_IDX:
+                if (virMacAddrParseHex((const char*)token,
+                    &mcast->macaddr) < 0) {
+                    virReportSystemError(EINVAL,
+                                         _("Failed to parse MAC address from '%s'"),
+                                         buf);
+                }
+
+                break;
+            default:
+                break;
+        }
+    }
+
+    return 0;
+}
+
+
+static void virNetDevMcastEntryListFree(size_t nentries,
+                                        virNetDevMcastEntryPtr *entries)
+{
+    size_t i;
+
+    if (entries) {
+        for (i = 0; i < nentries; i++)
+            VIR_FREE(entries[i]);
+
+        VIR_FREE(entries);
+    }
+}
+
+
+static int virNetDevGetMcast(const char *ifname,
+                             virNetDevMcastPtr mcast)
+{
+    char *cur = NULL;
+    char *buf = NULL;
+    char *next = NULL;
+    int ret = -1, len;
+    virNetDevMcastEntryPtr entry = NULL;
+    virNetDevMcastEntryPtr *entries = NULL;
+    size_t nentries = 0;
+    mcast->entries = NULL;
+    mcast->nentries = 0;
+
+    /* Read entire multicast table into memory */
+    if ((len = virFileReadAll(PROC_NET_DEV_MCAST, MAX_MCAST_SIZE, &buf)) <= 0)
+        goto cleanup;
+
+    cur = buf;
+
+    while (cur) {
+        if (!entry) {
+            if (VIR_ALLOC(entry))
+                goto cleanup;
+        }
+
+        next = strchr(cur, '\n');
+
+        if (next) {
+            next++;
+        }
+
+        if (virNetDevParseMcast(cur, entry))
+            goto cleanup;
+
+        /* Only return global multicast MAC addresses for
+         * specified interface */
+        if (entry->global && STREQ(ifname, entry->name)) {
+            if (VIR_APPEND_ELEMENT(entries, nentries, entry))
+                 goto cleanup;
+
+            entry = NULL;
+        } else {
+            memset(entry, 0, sizeof(virNetDevMcastEntry));
+        }
+
+        cur = next && ((next - buf) < len) ? next : NULL;
+    }
+
+    mcast->nentries = nentries;
+    mcast->entries = entries;
+    ret = 0;
+ cleanup:
+    if (ret < 0)
+        virNetDevMcastEntryListFree(nentries, entries);
+
+    VIR_FREE(entry);
+
+    return ret;
+}
+
+
 VIR_ENUM_IMPL(virNetDevRxFilterMode,
               VIR_NETDEV_RX_FILTER_MODE_LAST,
               "none",
@@ -1941,6 +2230,38 @@ VIR_ENUM_IMPL(virNetDevRxFilterMode,
               "all");
 
 
+static int virNetDevGetMulticastTable(const char *ifname,
+                                      virNetDevRxFilterPtr filter)
+{
+    size_t i;
+    int ret = -1;
+    virNetDevMcast mcast;
+    filter->multicast.nTable = 0;
+    filter->multicast.table = NULL;
+
+    if (virNetDevGetMcast(ifname, &mcast) < 0)
+        goto cleanup;
+
+    if (mcast.nentries > 0) {
+        if (VIR_ALLOC_N(filter->multicast.table, mcast.nentries))
+            goto cleanup;
+
+        for (i = 0; i < mcast.nentries; i++) {
+            virMacAddrSet(&filter->multicast.table[i],
+                          &mcast.entries[i]->macaddr);
+        }
+
+        filter->multicast.nTable = mcast.nentries;
+    }
+
+    ret = 0;
+ cleanup:
+    virNetDevMcastEntryListFree(mcast.nentries, mcast.entries);
+
+    return ret;
+}
+
+
 virNetDevRxFilterPtr
 virNetDevRxFilterNew(void)
 {
@@ -1963,3 +2284,40 @@ virNetDevRxFilterFree(virNetDevRxFilterPtr filter)
         VIR_FREE(filter);
     }
 }
+
+
+/**
+ * virNetDevGetRxFilter:
+ * This function supplies the RX filter list for a given device interface
+ *
+ * @ifname: Name of the interface
+ * @filter: The RX filter list
+ *
+ * Returns 0 or -1 on failure.
+ */
+int virNetDevGetRxFilter(const char *ifname,
+                         virNetDevRxFilterPtr *filter)
+{
+    int ret = -1;
+    virNetDevRxFilterPtr fil = virNetDevRxFilterNew();
+
+    if (!fil)
+        goto cleanup;
+
+    if (virNetDevGetMAC(ifname, &fil->mac))
+        goto cleanup;
+
+    if (virNetDevGetMulticastTable(ifname, fil))
+        goto cleanup;
+
+    ret = 0;
+ cleanup:
+    if (ret < 0) {
+        virNetDevRxFilterFree(fil);
+        fil = NULL;
+    }
+
+    *filter = fil;
+
+    return ret;
+}
diff --git a/src/util/virnetdev.h b/src/util/virnetdev.h
index 2a6e67d..ac4beff 100644
--- a/src/util/virnetdev.h
+++ b/src/util/virnetdev.h
@@ -189,5 +189,15 @@ int virNetDevGetLinkInfo(const char *ifname,
 virNetDevRxFilterPtr virNetDevRxFilterNew(void)
    ATTRIBUTE_RETURN_CHECK;
 void virNetDevRxFilterFree(virNetDevRxFilterPtr filter);
+int virNetDevGetRxFilter(const char *ifname,
+                         virNetDevRxFilterPtr *filter)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
+
+int virNetDevAddMulti(const char *ifname,
+                      virMacAddrPtr macaddr)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
+int virNetDevDelMulti(const char *ifname,
+                      virMacAddrPtr macaddr)
+    ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2) ATTRIBUTE_RETURN_CHECK;
 
 #endif /* __VIR_NETDEV_H__ */
-- 
1.7.1

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