From: Pieter Lexis <pieter.lexis@powerdns.com>
Date: Tue, 23 Jan 2018 15:14:40 +0000 (+0100)
Subject: Auth: add waitForMultiData function
X-Git-Tag: dnsdist-1.3.0~84^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d529011fee51367391f66be4a14015044fbe1e55;p=thirdparty%2Fpdns.git

Auth: add waitForMultiData function

And use this function in CommunicatorClass::doNotifications.
---

diff --git a/pdns/mastercommunicator.cc b/pdns/mastercommunicator.cc
index 2b6e25047a..ce227c7dd1 100644
--- a/pdns/mastercommunicator.cc
+++ b/pdns/mastercommunicator.cc
@@ -162,9 +162,10 @@ time_t CommunicatorClass::doNotifications()
   char buffer[1500];
   int sock;
   ssize_t size;
+  set<int> fds = {d_nsock4, d_nsock6};
 
   // receive incoming notifications on the nonblocking socket and take them off the list
-  while(waitFor2Data(d_nsock4, d_nsock6, 0, 0, &sock) > 0) {
+  while(waitForMultiData(fds, 0, 0, &sock) > 0) {
     fromlen=sizeof(from);
     size=recvfrom(sock,buffer,sizeof(buffer),0,(struct sockaddr *)&from,&fromlen);
     if(size < 0)
diff --git a/pdns/misc.cc b/pdns/misc.cc
index 8dc5d4b360..25a8c001fb 100644
--- a/pdns/misc.cc
+++ b/pdns/misc.cc
@@ -353,6 +353,46 @@ int waitForRWData(int fd, bool waitForRead, int seconds, int useconds, bool* err
   return ret;
 }
 
+// returns -1 in case of error, 0 if no data is available, 1 if there is. In the first two cases, errno is set
+int waitForMultiData(const set<int>& fds, const int seconds, const int useconds, int* fd) {
+  set<int> realFDs;
+  for (const auto& fd : fds) {
+    if (fd >= 0 && realFDs.count(fd) == 0) {
+      realFDs.insert(fd);
+    }
+  }
+
+  struct pollfd pfds[realFDs.size()];
+  memset(&pfds[0], 0, realFDs.size()*sizeof(struct pollfd));
+  int ctr = 0;
+  for (const auto& fd : realFDs) {
+    pfds[ctr].fd = fd;
+    pfds[ctr].events = POLLIN;
+    ctr++;
+  }
+
+  int ret;
+  if(seconds >= 0)
+    ret = poll(pfds, realFDs.size(), seconds * 1000 + useconds/1000);
+  else
+    ret = poll(pfds, realFDs.size(), -1);
+  if(ret <= 0)
+    return ret;
+
+  set<int> pollinFDs;
+  ctr = 0;
+  for (const auto& fd : realFDs) {
+    if (pfds[ctr].revents & POLLIN) {
+      pollinFDs.insert(pfds[ctr].fd);
+    }
+    ctr++;
+  }
+  set<int>::const_iterator it(pollinFDs.begin());
+  advance(it, random() % pollinFDs.size());
+  *fd = *it;
+  return 1;
+}
+
 // returns -1 in case of error, 0 if no data is available, 1 if there is. In the first two cases, errno is set
 int waitFor2Data(int fd1, int fd2, int seconds, int useconds, int*fd)
 {
diff --git a/pdns/misc.hh b/pdns/misc.hh
index f9db931a7c..6aff9ebc7b 100644
--- a/pdns/misc.hh
+++ b/pdns/misc.hh
@@ -63,6 +63,7 @@ string getHostname();
 string urlEncode(const string &text);
 int waitForData(int fd, int seconds, int useconds=0);
 int waitFor2Data(int fd1, int fd2, int seconds, int useconds, int* fd);
+int waitForMultiData(const set<int>& fds, const int seconds, const int useconds, int* fd);
 int waitForRWData(int fd, bool waitForRead, int seconds, int useconds, bool* error=nullptr, bool* disconnected=nullptr);
 uint16_t getShort(const unsigned char *p);
 uint16_t getShort(const char *p);