[PATCH v2 1/4] util: introduce helper to parse /proc/net/arp

[Chen Hanxiao <chen_han_xiao@xxxxxxx>]

From: Chen Hanxiao <chenhanxiao@xxxxxxxxx>

introduce helper to parse /proc/net/arp and
store it in struct virArpTable.

Signed-off-by: Chen Hanxiao <chenhanxiao@xxxxxxxxx>
---
 src/libvirt_private.syms |  2 ++
 src/util/virmacaddr.c    | 67 ++++++++++++++++++++++++++++++++++++++++++++++++
 src/util/virmacaddr.h    | 18 +++++++++++++
 3 files changed, 87 insertions(+)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index bc8cc1fba..26385a2e9 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -2133,6 +2133,8 @@ virLogVMessage;
 
 
 # util/virmacaddr.h
+virArpTableFree;
+virGetArpTable;
 virMacAddrCmp;
 virMacAddrCmpRaw;
 virMacAddrCompare;
diff --git a/src/util/virmacaddr.c b/src/util/virmacaddr.c
index 409fdc34d..540bdbbaa 100644
--- a/src/util/virmacaddr.c
+++ b/src/util/virmacaddr.c
@@ -27,10 +27,15 @@
 #include <stdio.h>
 
 #include "c-ctype.h"
+#include "viralloc.h"
+#include "virfile.h"
 #include "virmacaddr.h"
 #include "virrandom.h"
+#include "virstring.h"
 #include "virutil.h"
 
+#define VIR_FROM_THIS VIR_FROM_NONE
+
 static const unsigned char virMacAddrBroadcastAddrRaw[VIR_MAC_BUFLEN] =
     { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
 
@@ -257,3 +262,65 @@ virMacAddrIsBroadcastRaw(const unsigned char s[VIR_MAC_BUFLEN])
 {
     return memcmp(virMacAddrBroadcastAddrRaw, s, sizeof(*s)) == 0;
 }
+
+int
+virGetArpTable(virArpTablePtr *table)
+{
+#define PROC_NET_ARP    "/proc/net/arp"
+    FILE *fp = NULL;
+    char line[1024];
+    int num = 0;
+    int ret = -1;
+
+    if (!(fp = fopen(PROC_NET_ARP, "r")))
+        goto cleanup;
+
+    while (fgets(line, sizeof(line), fp)) {
+        char ip[32], mac[32], dev_name[32], hwtype[32],
+             flags[32], mask[32], nouse[32];
+
+        if (STRPREFIX(line, "IP address"))
+            continue;
+
+        num++;
+        if (VIR_REALLOC_N((*table)->t, num) < 0)
+            goto cleanup;
+        (*table)->n = num;
+        /* /proc/net/arp looks like:
+         * 172.16.17.254  0x1 0x2  e4:68:a3:8d:ed:d3  *   enp3s0
+         */
+        sscanf(line, "%[0-9.]%[ ]%[^ ]%[ ]%[^ ]%[ ]%[^ ]%[ ]%[^ ]%[ ]%[^ \t\n]",
+               ip, nouse,
+               hwtype, nouse,
+               flags, nouse,
+               mac, nouse,
+               mask, nouse,
+               dev_name);
+
+
+        if (VIR_STRDUP((*table)->t[num - 1].ipaddr, ip) < 0)
+            goto cleanup;
+        if (VIR_STRDUP((*table)->t[num - 1].mac, mac) < 0)
+            goto cleanup;
+        if (VIR_STRDUP((*table)->t[num - 1].dev_name, dev_name) < 0)
+            goto cleanup;
+    }
+
+    ret = 0;
+
+ cleanup:
+    VIR_FORCE_FCLOSE(fp);
+    return ret;
+}
+
+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->t[i].dev_name);
+    }
+    VIR_FREE(table);
+}
diff --git a/src/util/virmacaddr.h b/src/util/virmacaddr.h
index ef4285d63..eb18092d1 100644
--- a/src/util/virmacaddr.h
+++ b/src/util/virmacaddr.h
@@ -40,6 +40,22 @@ struct _virMacAddr {
                        false otherwise. */
 };
 
+typedef struct _virArpTableEntry virArpTableEntry;
+typedef virArpTableEntry *virArpTableEntryPtr;
+typedef struct _virArpTable virArpTable;
+typedef virArpTable *virArpTablePtr;
+
+struct _virArpTableEntry{
+    char *ipaddr;
+    char *mac;
+    char *dev_name;
+};
+
+struct _virArpTable {
+    int n;
+    virArpTableEntryPtr t;
+};
+
 int virMacAddrCompare(const char *mac1, const char *mac2);
 int virMacAddrCmp(const virMacAddr *mac1, const virMacAddr *mac2);
 int virMacAddrCmpRaw(const virMacAddr *mac1,
@@ -59,5 +75,7 @@ int virMacAddrParseHex(const char* str,
 bool virMacAddrIsUnicast(const virMacAddr *addr);
 bool virMacAddrIsMulticast(const virMacAddr *addr);
 bool virMacAddrIsBroadcastRaw(const unsigned char s[VIR_MAC_BUFLEN]);
+int virGetArpTable(virArpTablePtr *table);
+void virArpTableFree(virArpTablePtr table);
 
 #endif /* __VIR_MACADDR_H__ */
-- 
2.14.3

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