561882: net-snmpd reports wrong speed for disconnected interfaces

Source: upstream, SVN rev. 18099

Index: net-snmp/include/net-snmp/data_access/interface.h
===================================================================
--- net-snmp/include/net-snmp/data_access/interface.h	(revision 18098)
+++ net-snmp/include/net-snmp/data_access/interface.h	(revision 18099)
@@ -71,6 +71,9 @@
 
 #endif                          /* ifOperStatus_ENUMS */
 
+/* nominal speed of network interface - used when the real speed is unknown */
+#define NOMINAL_LINK_SPEED 10000000
+
 /**---------------------------------------------------------------------*/
 /*
  * structure definitions
Index: net-snmp/agent/mibgroup/if-mib/data_access/interface_linux.c
===================================================================
--- net-snmp/agent/mibgroup/if-mib/data_access/interface_linux.c	(revision 18098)
+++ net-snmp/agent/mibgroup/if-mib/data_access/interface_linux.c	(revision 18099)
@@ -61,10 +61,12 @@
 #endif  /* HAVE_PTHREAD_H && HAVE_LINUX_RTNETLINK_H */
 #endif  /* NETSNMP_ENABLE_IPV6 */
 unsigned long long
-netsnmp_linux_interface_get_if_speed(int fd, const char *name);
+netsnmp_linux_interface_get_if_speed(int fd, const char *name,
+        unsigned long long defaultspeed);
 #ifdef HAVE_LINUX_ETHTOOL_H
 unsigned long long
-netsnmp_linux_interface_get_if_speed_mii(int fd, const char *name);
+netsnmp_linux_interface_get_if_speed_mii(int fd, const char *name,
+        unsigned long long defaultspeed);
 #endif
 
 #define PROC_SYS_NET_IPVx_NEIGH_RETRANS_TIME_MS "/proc/sys/net/ipv%d/neigh/%s/retrans_time_ms"
@@ -694,7 +696,17 @@
         }
 
         if (IANAIFTYPE_ETHERNETCSMACD == entry->type) {
-            unsigned long long speed = netsnmp_linux_interface_get_if_speed(fd, entry->name);
+            unsigned long long speed;
+            unsigned long long defaultspeed = NOMINAL_LINK_SPEED;
+            if (!(entry->os_flags & IFF_RUNNING)) {
+                /*
+                 * use speed 0 if the if speed cannot be determined *and* the
+                 * interface is down
+                 */
+                defaultspeed = 0;
+            }
+            speed = netsnmp_linux_interface_get_if_speed(fd,
+                    entry->name, defaultspeed);
             if (speed > 0xffffffffL) {
                 entry->speed = 0xffffffff;
             } else
@@ -789,7 +801,8 @@
  * Determines network interface speed from ETHTOOL_GSET
  */
 unsigned long long
-netsnmp_linux_interface_get_if_speed(int fd, const char *name)
+netsnmp_linux_interface_get_if_speed(int fd, const char *name,
+            unsigned long long defaultspeed)
 {
     struct ifreq ifr;
     struct ethtool_cmd edata;
@@ -804,7 +817,7 @@
     if (ioctl(fd, SIOCETHTOOL, &ifr) == -1) {
         DEBUGMSGTL(("mibII/interfaces", "ETHTOOL_GSET on %s failed\n",
                     ifr.ifr_name));
-        return netsnmp_linux_interface_get_if_speed_mii(fd,name);
+        return netsnmp_linux_interface_get_if_speed_mii(fd,name,defaultspeed);
     }
     
     if (edata.speed != SPEED_10 && edata.speed != SPEED_100
@@ -818,7 +831,7 @@
         DEBUGMSGTL(("mibII/interfaces", "fallback to mii for %s\n",
                     ifr.ifr_name));
         /* try MII */
-        return netsnmp_linux_interface_get_if_speed_mii(fd,name);
+        return netsnmp_linux_interface_get_if_speed_mii(fd,name,defaultspeed);
     }
 
     /* return in bps */
@@ -833,12 +846,14 @@
  */
 unsigned long long
 #ifdef HAVE_LINUX_ETHTOOL_H
-netsnmp_linux_interface_get_if_speed_mii(int fd, const char *name)
+netsnmp_linux_interface_get_if_speed_mii(int fd, const char *name,
+        unsigned long long  defaultspeed)
 #else
-netsnmp_linux_interface_get_if_speed(int fd, const char *name)
+netsnmp_linux_interface_get_if_speed(int fd, const char *name,
+        unsigned long long defaultspeed)
 #endif
 {
-    unsigned long long retspeed = 10000000;
+    unsigned long long retspeed = defaultspeed;
     struct ifreq ifr;
 
     /* the code is based on mii-diag utility by Donald Becker
Index: net-snmp/agent/mibgroup/mibII/interfaces.c
===================================================================
--- net-snmp/agent/mibgroup/mibII/interfaces.c	(revision 18098)
+++ net-snmp/agent/mibgroup/mibII/interfaces.c	(revision 18099)
@@ -1439,16 +1439,17 @@
 * Determines network interface speed. It is system specific. Only linux
 * realization is made. 
 */
-unsigned int getIfSpeed(int fd, struct ifreq ifr)
+unsigned int getIfSpeed(int fd, struct ifreq ifr, unsigned int defaultspeed)
 {
 #ifdef linux
     /** temporary expose internal until this module can be re-written */
     extern unsigned int
-        netsnmp_linux_interface_get_if_speed(int fd, const char *name);
+        netsnmp_linux_interface_get_if_speed(int fd, const char *name,
+                unsigned long long defaultspeed);
 
-    return netsnmp_linux_interface_get_if_speed(fd, ifr.ifr_name);
+    return netsnmp_linux_interface_get_if_speed(fd, ifr.ifr_name, defaultspeed);
 #else /*!linux*/			   
-    return 10000000;
+    return defaultspeed;
 #endif 
 }
 
@@ -1769,11 +1770,30 @@
              * do only guess if_type from name, if we could not read
              * * it before from SIOCGIFHWADDR 
              */
+            unsigned int defaultspeed = NOMINAL_LINK_SPEED;
+                if (!(nnew->if_flags & IFF_RUNNING)) {
+                    /* 
+                     * use speed 0 if the if speed cannot be determined *and* the
+                     * interface is down
+                     */
+                    defaultspeed = 0;
+                }
+
             if (!nnew->if_type)
                 nnew->if_type = if_type_from_name(nnew->if_name);
-            nnew->if_speed = nnew->if_type == 6 ? getIfSpeed(fd, ifrq) :
-                nnew->if_type == 24 ? 10000000 :
-                nnew->if_type == 9 ? 4000000 : 0;
+            switch(nnew->if_type) {
+            case 6:
+                nnew->if_speed = getIfSpeed(fd, ifrq, defaultspeed);
+                break;
+            case 24:
+                nnew->if_speed = 10000000;
+                break;
+            case 9:
+                nnew->if_speed = 4000000;
+                break;
+            default:
+                nnew->if_speed = 0;
+            }
             /*Zero speed means link problem*/
             if(nnew->if_speed == 0 && nnew->if_flags & IFF_UP){
                 nnew->if_flags &= ~IFF_RUNNING;