Adding upstream version 1.7.3.upstream/1.7.3upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 206 insertions, 0 deletions

diff --git a/snmp-agent.cc b/snmp-agent.cc
new file mode 100644
index 0000000..4b2bc6b
--- /dev/null
+++ b/snmp-agent.cc
@@ -0,0 +1,206 @@
+#include "snmp-agent.hh"
+#include "misc.hh"
+#include "threadname.hh"
+#ifdef RECURSOR
+#include "logger.hh"
+#else
+#include "dolog.hh"
+#endif
+
+#ifdef HAVE_NET_SNMP
+
+#ifndef HAVE_SNMP_SELECT_INFO2
+/* that's terrible, because it means we are going to have trouble with large
+   FD numbers at some point.. */
+# define netsnmp_large_fd_set fd_set
+# define snmp_read2 snmp_read
+# define snmp_select_info2 snmp_select_info
+# define netsnmp_large_fd_set_init(...)
+# define netsnmp_large_fd_set_cleanup(...)
+# define NETSNMP_LARGE_FD_SET FD_SET
+# define NETSNMP_LARGE_FD_CLR FD_CLR
+# define NETSNMP_LARGE_FD_ZERO FD_ZERO
+# define NETSNMP_LARGE_FD_ISSET FD_ISSET
+#else
+# include <net-snmp/library/large_fd_set.h>
+#endif
+
+const oid SNMPAgent::snmpTrapOID[] = { 1, 3, 6, 1, 6, 3, 1, 1, 4, 1, 0 };
+const size_t SNMPAgent::snmpTrapOIDLen = OID_LENGTH(SNMPAgent::snmpTrapOID);
+
+int SNMPAgent::setCounter64Value(netsnmp_request_info* request,
+                                 uint64_t value)
+{
+  struct counter64 val64;
+  val64.high = value >> 32;
+  val64.low = value & 0xffffffff;
+  snmp_set_var_typed_value(request->requestvb,
+                           ASN_COUNTER64,
+                           &val64,
+                           sizeof(val64));
+  return SNMP_ERR_NOERROR;
+}
+
+bool SNMPAgent::sendTrap(int fd,
+                         netsnmp_variable_list* varList)
+{
+  ssize_t written = write(fd, &varList, sizeof(varList));
+
+  if (written != sizeof(varList)) {
+    snmp_free_varbind(varList);
+    return false;
+  }
+  return true;
+}
+
+void SNMPAgent::handleTrapsEvent()
+{
+  netsnmp_variable_list* varList = nullptr;
+  ssize_t got = 0;
+
+  do {
+    got = read(d_trapPipe[0], &varList, sizeof(varList));
+
+    if (got == sizeof(varList)) {
+      send_v2trap(varList);
+      snmp_free_varbind(varList);
+    }
+  }
+  while (got > 0);
+}
+
+void SNMPAgent::handleSNMPQueryEvent(int fd)
+{
+  netsnmp_large_fd_set fdset;
+  netsnmp_large_fd_set_init(&fdset, FD_SETSIZE);
+  NETSNMP_LARGE_FD_ZERO(&fdset);
+  NETSNMP_LARGE_FD_SET(fd, &fdset);
+  snmp_read2(&fdset);
+}
+
+void SNMPAgent::handleTrapsCB(int fd, FDMultiplexer::funcparam_t& var)
+{
+  SNMPAgent** agent = boost::any_cast<SNMPAgent*>(&var);
+  if (!agent || !*agent)
+    throw std::runtime_error("Invalid value received in SNMP trap callback");
+
+  (*agent)->handleTrapsEvent();
+}
+
+void SNMPAgent::handleSNMPQueryCB(int fd, FDMultiplexer::funcparam_t& var)
+{
+  SNMPAgent** agent = boost::any_cast<SNMPAgent*>(&var);
+  if (!agent || !*agent)
+    throw std::runtime_error("Invalid value received in SNMP trap callback");
+
+  (*agent)->handleSNMPQueryEvent(fd);
+}
+
+#endif /* HAVE_NET_SNMP */
+
+void SNMPAgent::worker()
+{
+#ifdef HAVE_NET_SNMP
+  FDMultiplexer* mplexer = FDMultiplexer::getMultiplexerSilent();
+  if (mplexer == nullptr) {
+    throw std::runtime_error("No FD multiplexer found for the SNMP agent!");
+  }
+
+#ifdef RECURSOR
+  string threadName = "pdns-r/SNMP";
+#else
+  string threadName = "dnsdist/SNMP";
+#endif
+  setThreadName(threadName);
+
+  int maxfd = 0;
+  int block = 1;
+  netsnmp_large_fd_set fdset;
+  struct timeval timeout = { 0, 0 };
+  struct timeval now;
+
+  /* we want to be notified if a trap is waiting
+   to be sent */
+  mplexer->addReadFD(d_trapPipe[0], &handleTrapsCB, this);
+
+  while(true) {
+    netsnmp_large_fd_set_init(&fdset, FD_SETSIZE);
+    NETSNMP_LARGE_FD_ZERO(&fdset);
+
+    block = 1;
+    timeout = { 0, 0 };
+    snmp_select_info2(&maxfd, &fdset, &timeout, &block);
+
+    for (int fd = 0; fd < maxfd; fd++) {
+      if (NETSNMP_LARGE_FD_ISSET(fd, &fdset)) {
+        mplexer->addReadFD(fd, &handleSNMPQueryCB, this);
+      }
+    }
+
+    /* run updates now */
+    int res = mplexer->run(&now, (timeout.tv_sec * 1000) + (timeout.tv_usec / 1000));
+
+    /* we handle timeouts here, the rest has already been handled by callbacks */
+    if (res == 0) {
+      snmp_timeout();
+      run_alarms();
+    }
+
+    for (int fd = 0; fd < maxfd; fd++) {
+      if (NETSNMP_LARGE_FD_ISSET(fd, &fdset)) {
+        try {
+          mplexer->removeReadFD(fd);
+        }
+        catch(const FDMultiplexerException& e) {
+          /* we might get an exception when removing a closed file descriptor,
+             just ignore it */
+        }
+      }
+    }
+  }
+#endif /* HAVE_NET_SNMP */
+}
+
+SNMPAgent::SNMPAgent(const std::string& name, const std::string& daemonSocket)
+{
+#ifdef HAVE_NET_SNMP
+  netsnmp_enable_subagent();
+  snmp_disable_log();
+  if (!daemonSocket.empty()) {
+    netsnmp_ds_set_string(NETSNMP_DS_APPLICATION_ID,
+                          NETSNMP_DS_AGENT_X_SOCKET,
+                          daemonSocket.c_str());
+  }
+  /* no need to load any MIBS,
+     and it causes import errors if some modules are not present */
+  setenv("MIBS", "", 1);
+
+  init_agent(name.c_str());
+
+  /* we use select() so don't use SIGALARM to handle alarms.
+     Note that we need to handle alarms for automatic reconnection
+     to the daemon to work.
+  */
+  netsnmp_ds_set_boolean(NETSNMP_DS_LIBRARY_ID,
+                         NETSNMP_DS_LIB_ALARM_DONT_USE_SIG,
+                         1);
+
+  init_snmp(name.c_str());
+
+  if (pipe(d_trapPipe) < 0)
+    unixDie("Creating pipe");
+
+  if (!setNonBlocking(d_trapPipe[0])) {
+    close(d_trapPipe[0]);
+    close(d_trapPipe[1]);
+    unixDie("Setting pipe non-blocking");
+  }
+
+  if (!setNonBlocking(d_trapPipe[1])) {
+    close(d_trapPipe[0]);
+    close(d_trapPipe[1]);
+    unixDie("Setting pipe non-blocking");
+  }
+
+#endif /* HAVE_NET_SNMP */
+}