Patch to address a scalability issue when using dnsmasq in Openstack,

that causes DHCP to be extremely slow.

This patch was developed in-house. Since it is Solaris-specific, it is not

suitable for upstream.

--- dnsmasq-2.75/src/dhcp-common.c	2015-07-30 12:59:07.000000000 -0700

+++ new/src/dhcp-common.c	2016-09-22 15:12:02.104708123 -0700

@@ -493,6 +493,58 @@

       errno != EPERM)

     die(_("failed to set SO_BINDTODEVICE on DHCP socket: %s"), NULL, EC_BADNET);

 }

+#elif defined(HAVE_SOLARIS_NETWORK)

+int which_ifindex(void)

+{

+  /* If we are doing DHCP on exactly one interface, and using Solaris, we want

+   * to limit packet transmission/reception to that interface using IP_BOUND_IF

+   * for IPv4 and IPV6_BOUND_IF for IPv6. This is for the use case of OpenStack,

+   * which runs a new dnsmasq instance for each network it creates. Without this

+   * socket option, each of the dnsmasq process would unnecessarily process 

+   * packets that arrive on other interfaces as well, thus slowing down the 

+   * entire DHCP process.

+   */

+

+   struct irec *iface, *found;

+   struct iname *if_tmp;

+

+   if (!daemon->if_names)

+     return -1;

+

+   for (if_tmp = daemon->if_names; if_tmp; if_tmp = if_tmp->next)

+     if (if_tmp->name && (!if_tmp->used || strchr(if_tmp->name, '*')))

+       return -1;

+ 

+   for (found = NULL, iface = daemon->interfaces; iface; iface = iface->next)

+     if (iface->dhcp_ok)

+       {

+	 if (!found)

+	   found = iface;

+	 else if (strcmp(found->name, iface->name) != 0)

+	   return -1; /* more than one. */

+       }

+

+   if (found)

+     return found->index;

+

+   return -1;

+}

+

+void bindtoif(int ifindex, int fd, int is_dhcp6)

+{

+  if (is_dhcp6)

+    {

+      if (setsockopt(fd, IPPROTO_IPV6, IPV6_BOUND_IF, (char *)&ifindex, sizeof(ifindex)) == -1 && 

+          errno != EPERM)

+        die(_("failed to set IPv6_BOUND_IF on DHCP socket: %s"), NULL, EC_BADNET);

+    }

+  else

+    {

+      if (setsockopt(fd, IPPROTO_IP, IP_BOUND_IF, &ifindex, sizeof(ifindex)) == -1 &&

+          errno != EPERM)

+        die(_("failed to set IP_BOUND_IF on DHCP socket: %s"), NULL, EC_BADNET);

+    }

+}

 #endif

 static const struct opttab_t {

--- dnsmasq-2.75/src/dnsmasq.h	2016-09-22 15:20:19.502011580 -0700

+++ new/src/dnsmasq.h	2016-09-22 13:17:03.865473011 -0700

@@ -1464,6 +1464,9 @@

 #ifdef HAVE_LINUX_NETWORK

 char *whichdevice(void);

 void bindtodevice(char *device, int fd);

+#elif defined(HAVE_SOLARIS_NETWORK)

+int which_ifindex(void);

+void bindtoif(int ifindex, int fd, int is_dhcp6);

 #endif

 #  ifdef HAVE_DHCP6

 void display_opts6(void);

--- dnsmasq-2.75/src/dnsmasq.c	2015-07-30 12:59:07.000000000 -0700

+++ new/src/dnsmasq.c	2016-09-22 15:20:03.040122945 -0700

@@ -54,6 +54,10 @@

   char *bound_device = NULL;

   int did_bind = 0;

 #endif 

+#if defined(HAVE_SOLARIS_NETWORK)

+  int bound_ifindex = -1;

+  int did_bind = 0;

+#endif

 #if defined(HAVE_DHCP) || defined(HAVE_DHCP6)

   struct dhcp_context *context;

   struct dhcp_relay *relay;

@@ -306,6 +310,23 @@

 	      did_bind = 1;

 	    }

 	}

+#elif defined(HAVE_SOLARIS_NETWORK) && defined(HAVE_DHCP)

+      bound_ifindex = which_ifindex();

+

+      if (daemon->dhcp)

+	{

+          if (!daemon->relay4 && bound_ifindex >= 0)

+            {

+	      bindtoif(bound_ifindex, daemon->dhcpfd, 0);

+	      did_bind = 1;

+	    }

+

+	  if (daemon->enable_pxe && bound_ifindex >= 0)

+	    {

+              bindtoif(bound_ifindex, daemon->pxefd, 0);

+	      did_bind = 1;

+	    }

+	}

 #endif

 #if defined(HAVE_LINUX_NETWORK) && defined(HAVE_DHCP6)

@@ -314,6 +335,12 @@

 	  bindtodevice(bound_device, daemon->dhcp6fd);

 	  did_bind = 1;

 	}

+#elif defined(HAVE_SOLARIS_NETWORK) && defined(HAVE_DHCP6)

+      if (daemon->doing_dhcp6 && !daemon->relay6 && bound_ifindex >= 0)

+	{

+          bindtoif(bound_ifindex, daemon->dhcp6fd, 1);

+	  did_bind = 1;

+	}

 #endif

     }

   else 

@@ -788,6 +815,9 @@

 #  ifdef HAVE_LINUX_NETWORK

   if (did_bind)

     my_syslog(MS_DHCP | LOG_INFO, _("DHCP, sockets bound exclusively to interface %s"), bound_device);

+#  elif defined(HAVE_SOLARIS_NETWORK)

+  if (did_bind)

+    my_syslog(MS_DHCP | LOG_INFO, _("DHCP, sockets bound exclusively to interface index %d"), bound_ifindex);

 #  endif

   /* after dhcp_contruct_contexts */