commit 64d3d2c83b30c751570faf0c5d527ff3da9f2036

Author: Beniamino Galvani <bgalvani@redhat.com>

Date:   Sun Aug 28 20:44:05 2016 +0100

    Handle binding upstream servers to an interface

    (--server=1.2.3.4@eth0) when the named interface

    is destroyed and recreated in the kernel.

diff --git a/src/dbus.c b/src/dbus.c

index 7379341..e56d8c7 100644

--- a/src/dbus.c

+++ b/src/dbus.c

@@ -161,6 +161,10 @@ static void add_update_server(union mysockaddr *addr,

   if (serv)

     {

+      serv->sfd = NULL;

+      serv->queries = 0;

+      serv->failed_queries = 0;

+

       if (interface)

 	strcpy(serv->interface, interface);

       else

diff --git a/src/dnsmasq.h b/src/dnsmasq.h

index 69ae7a7..7b8020e 100644

--- a/src/dnsmasq.h

+++ b/src/dnsmasq.h

@@ -412,6 +412,7 @@ struct serverfd {

   int fd;

   union mysockaddr source_addr;

   char interface[IF_NAMESIZE+1];

+  unsigned int ifindex, used;

   struct serverfd *next;

 };

diff --git a/src/network.c b/src/network.c

index 792914b..d2bebcc 100644

--- a/src/network.c

+++ b/src/network.c

@@ -839,6 +839,7 @@ int local_bind(int fd, union mysockaddr *addr, char *intname, int is_tcp)

 static struct serverfd *allocate_sfd(union mysockaddr *addr, char *intname)

 {

   struct serverfd *sfd;

+  unsigned int ifindex = 0;

   int errsave;

   /* when using random ports, servers which would otherwise use

@@ -859,11 +860,15 @@ static struct serverfd *allocate_sfd(union mysockaddr *addr, char *intname)

 	return NULL;

 #endif

     }

+

+  if (intname && strlen(intname) != 0)

+    ifindex = if_nametoindex(intname); /* index == 0 when not binding to an interface */

   /* may have a suitable one already */

   for (sfd = daemon->sfds; sfd; sfd = sfd->next )

     if (sockaddr_isequal(&sfd->source_addr, addr) &&

-	strcmp(intname, sfd->interface) == 0)

+	strcmp(intname, sfd->interface) == 0 &&

+	ifindex == sfd->ifindex) 

       return sfd;

   /* need to make a new one. */

@@ -885,11 +890,13 @@ static struct serverfd *allocate_sfd(union mysockaddr *addr, char *intname)

       errno = errsave;

       return NULL;

     }

-    

+

   strcpy(sfd->interface, intname); 

   sfd->source_addr = *addr;

   sfd->next = daemon->sfds;

+  sfd->ifindex = ifindex;

   daemon->sfds = sfd;

+

   return sfd; 

 }

@@ -944,12 +951,16 @@ void check_servers(void)

 {

   struct irec *iface;

   struct server *new, *tmp, *ret = NULL;

+  struct serverfd *sfd, *tmpfd, **up;

   int port = 0;

   /* interface may be new since startup */

   if (!option_bool(OPT_NOWILD))

     enumerate_interfaces();

+  for (sfd = daemon->sfds; sfd; sfd = sfd->next)

+    sfd->used = 0;

+

   for (new = daemon->servers; new; new = tmp)

     {

       tmp = new->next;

@@ -987,6 +998,9 @@ void check_servers(void)

 	      free(new);

 	      continue;

 	    }

+

+	  if (new->sfd)

+	    new->sfd->used = 1;

 	}

       /* reverse order - gets it right. */

@@ -1019,6 +1033,20 @@ void check_servers(void)

 	}

     }

+  /* Remove unused sfds */

+  for (sfd = daemon->sfds, up = &daemon->sfds; sfd; sfd = tmpfd)

+    {

+       tmpfd = sfd->next;

+       if (!sfd->used) 

+	{

+	  *up = sfd->next;

+	  close(sfd->fd);

+	  free(sfd);

+	} 

+      else

+	up = &sfd->next;

+    }

+  

   daemon->servers = ret;

 }