[libvirt] [PATCH v4 2/5] util: introduce helper to parse message from RTM_GETNEIGH query
Chen Hanxiao
chen_han_xiao at 126.com
Thu Feb 8 07:47:01 UTC 2018
From: Chen Hanxiao <chenhanxiao at gmail.com>
introduce helper to parse RTM_GETNEIGH query message and
store it in struct virArpTable.
Signed-off-by: Chen Hanxiao <chenhanxiao at gmail.com>
---
v4:
use netlink query instead of parsing /proc/net/arp
v3:
s/virGetArpTable/virArpTableGet
alloc virArpTable in virArpTableGet
return ENOSUPP on none-Linux platform
move helpers to virarptable.[ch]
po/POTFILES.in | 1 +
src/Makefile.am | 1 +
src/libvirt_private.syms | 5 ++
src/util/virarptable.c | 182 +++++++++++++++++++++++++++++++++++++++++++++++
src/util/virarptable.h | 47 ++++++++++++
5 files changed, 236 insertions(+)
create mode 100644 src/util/virarptable.c
create mode 100644 src/util/virarptable.h
diff --git a/po/POTFILES.in b/po/POTFILES.in
index cbf2accba..0f2ba7490 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -193,6 +193,7 @@ src/uml/uml_conf.c
src/uml/uml_driver.c
src/util/iohelper.c
src/util/viralloc.c
+src/util/virarptable.c
src/util/viraudit.c
src/util/virauth.c
src/util/virauthconfig.c
diff --git a/src/Makefile.am b/src/Makefile.am
index 79adc9ba5..dd79b58e0 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -98,6 +98,7 @@ augeastest_DATA =
UTIL_SOURCES = \
util/viralloc.c util/viralloc.h \
util/virarch.h util/virarch.c \
+ util/virarptable.h util/virarptable.c \
util/viratomic.h util/viratomic.c \
util/viraudit.c util/viraudit.h \
util/virauth.c util/virauth.h \
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index d90eb3dde..1167220f2 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1346,6 +1346,11 @@ virArchGetWordSize;
virArchToString;
+# util/virarptable.h
+virArpTableFree;
+virArpTableGet;
+
+
# util/viraudit.h
virAuditClose;
virAuditEncode;
diff --git a/src/util/virarptable.c b/src/util/virarptable.c
new file mode 100644
index 000000000..cbf085403
--- /dev/null
+++ b/src/util/virarptable.c
@@ -0,0 +1,182 @@
+/*
+ * virarptable.c Linux ARP table handling
+ *
+ * Copyright (C) 2018 Chen Hanxiao
+ *
+ * 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, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ * Chen Hanxiao <chenhanxiao at gmail.com>
+ */
+
+#include <config.h>
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <arpa/inet.h>
+
+#include "viralloc.h"
+#include "virarptable.h"
+#include "virfile.h"
+#include "virlog.h"
+#include "virnetlink.h"
+#include "virsocketaddr.h"
+#include "virstring.h"
+
+#define VIR_FROM_THIS VIR_FROM_NONE
+
+VIR_LOG_INIT("util.arptable");
+
+#ifdef __linux__
+
+# define NDA_RTA(r) \
+ ((struct rtattr*)(((char*)(r)) + NLMSG_ALIGN(sizeof(struct ndmsg))))
+
+static int
+parse_rtattr(struct rtattr *tb[], int max, struct rtattr *rta, int len)
+{
+ memset(tb, 0, sizeof(struct rtattr *) * (max + 1));
+ while (RTA_OK(rta, len)) {
+ if ((rta->rta_type <= max) && (!tb[rta->rta_type]))
+ tb[rta->rta_type] = rta;
+ rta = RTA_NEXT(rta, len);
+ }
+
+ if (len)
+ VIR_WARN("malformed netlink message: Deficit %d, rta_len=%d",
+ len, rta->rta_len);
+ return 0;
+}
+
+virArpTablePtr virArpTableGet(void)
+{
+ int num = 0;
+ int msglen;
+ void *nlData = NULL;
+ virArpTablePtr table = NULL;
+ char *ipstr = NULL;
+ struct nlmsghdr* nh;
+ struct rtattr * tb[NDA_MAX+1];
+
+ msglen = virNetlinkGetNeighbor(&nlData, 0, 0);
+ if (msglen < 0)
+ return NULL;
+
+ if (VIR_ALLOC(table) < 0)
+ return NULL;
+
+ nh = (struct nlmsghdr*)nlData;
+
+ while (NLMSG_OK(nh, msglen)) {
+ struct ndmsg *r = NLMSG_DATA(nh);
+ int len = nh->nlmsg_len;
+ void *addr;
+
+ if ((len -= NLMSG_LENGTH(sizeof(*nh))) < 0) {
+ virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+ _("wrong nlmsg len"));
+ goto cleanup;
+ }
+
+ if (r->ndm_family && (r->ndm_family != AF_INET))
+ goto next_nlmsg;
+
+ /* catch stale and reachalbe arp entry only */
+ if (r->ndm_state &&
+ (!(r->ndm_state == NUD_STALE || r->ndm_state == NUD_REACHABLE))) {
+ nh = NLMSG_NEXT(nh, msglen);
+ continue;
+ }
+
+ if (nh->nlmsg_type == NLMSG_DONE)
+ goto end_of_netlink_messages;
+
+ parse_rtattr(tb, NDA_MAX, NDA_RTA(r),
+ nh->nlmsg_len - NLMSG_LENGTH(sizeof(*r)));
+
+ if (tb[NDA_DST] == NULL || tb[NDA_LLADDR] == NULL)
+ goto next_nlmsg;
+
+ if (tb[NDA_DST]) {
+ virSocketAddr virAddr;
+ if (VIR_REALLOC_N(table->t, num + 1) < 0)
+ goto cleanup;
+
+ table->n = num + 1;
+
+ addr = RTA_DATA(tb[NDA_DST]);
+ bzero(&virAddr, sizeof(virAddr));
+ virAddr.len = sizeof(virAddr.data.inet4);
+ virAddr.data.inet4.sin_family = AF_INET;
+ virAddr.data.inet4.sin_addr = *(struct in_addr *)addr;
+ ipstr = virSocketAddrFormat(&virAddr);
+
+ if (VIR_STRDUP(table->t[num].ipaddr, ipstr) < 0)
+ goto cleanup;
+
+ VIR_FREE(ipstr);
+ }
+
+ if (tb[NDA_LLADDR]) {
+ virMacAddr macaddr;
+ char ifmac[VIR_MAC_STRING_BUFLEN];
+
+ addr = RTA_DATA(tb[NDA_LLADDR]);
+ memcpy(macaddr.addr, addr, VIR_MAC_BUFLEN);
+ macaddr.generated = false;
+
+ virMacAddrFormat(&macaddr, ifmac);
+
+ if (VIR_STRDUP(table->t[num].mac, ifmac) < 0)
+ goto cleanup;
+
+ num++;
+ }
+
+ next_nlmsg:
+ nh = NLMSG_NEXT(nh, msglen);
+ }
+
+ end_of_netlink_messages:
+ VIR_FREE(nlData);
+ return table;
+
+ cleanup:
+ VIR_FREE(ipstr);
+ VIR_FREE(nlData);
+ return NULL;
+}
+
+#else
+
+virArpTablePtr virArpTableGet(void)
+{
+ virReportError(VIR_ERR_NO_SUPPORT, "%s",
+ _("get arp table not implemented on this platform"));
+ return NULL;
+}
+
+#endif /* __linux__ */
+
+void
+virArpTableFree(virArpTablePtr table)
+{
+ size_t i;
+ for (i = 0; i < table->n; i++) {
+ VIR_FREE(table->t[i].ipaddr);
+ VIR_FREE(table->t[i].mac);
+ }
+ VIR_FREE(table);
+}
diff --git a/src/util/virarptable.h b/src/util/virarptable.h
new file mode 100644
index 000000000..682919812
--- /dev/null
+++ b/src/util/virarptable.h
@@ -0,0 +1,47 @@
+/*
+ * virarptable.h Linux ARP table handling
+ *
+ * Copyright (C) 2018 Chen Hanxiao
+ *
+ * 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, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Authors:
+ * Chen Hanxiao <chenhanxiao at gmail.com>
+ */
+
+#ifndef __VIR_ARPTABLE_H__
+# define __VIR_ARPTABLE_H__
+
+# include "internal.h"
+
+typedef struct _virArpTableEntry virArpTableEntry;
+typedef virArpTableEntry *virArpTableEntryPtr;
+typedef struct _virArpTable virArpTable;
+typedef virArpTable *virArpTablePtr;
+
+struct _virArpTableEntry{
+ char *ipaddr;
+ char *mac;
+};
+
+struct _virArpTable {
+ int n;
+ virArpTableEntryPtr t;
+};
+
+virArpTablePtr virArpTableGet(void);
+void virArpTableFree(virArpTablePtr table);
+
+#endif /* __VIR_ARPTABLE_H__ */
--
2.14.3
More information about the libvir-list
mailing list