Add support for large SIOCGIFCONF returns (Greg Fausak).

diff --git a/common/discover.c b/common/discover.c
index 3075cbca13bd329541a8a07bd92cf71c7d5a4da7..cc198fe2ebcf07f436d77c809ec682df655863a1 100644 (file)
--- a/common/discover.c
+++ b/common/discover.c
@@ -43,7 +43,7 @@
 
 #ifndef lint
 static char copyright[] =
-"$Id: discover.c,v 1.31 2000/09/01 23:03:33 mellon Exp $ Copyright (c) 1995-2000 The Internet Software Consortium.  All rights reserved.\n";
+"$Id: discover.c,v 1.32 2000/09/04 22:27:41 mellon Exp $ Copyright (c) 1995-2000 The Internet Software Consortium.  All rights reserved.\n";
 #endif /* not lint */
 
 #include "dhcpd.h"
@@ -79,7 +79,7 @@ void discover_interfaces (state)
 {
        struct interface_info *tmp, *ip;
        struct interface_info *last, *next;
-       char buf [8192];
+       char buf [512];
        struct ifconf ic;
        struct ifreq ifr;
        int i;
@@ -95,6 +95,7 @@ void discover_interfaces (state)
 #endif
        isc_result_t status;
        static int setup_fallback = 0;
+       int wifcount = 0;
 
        if (!dhcp_type_interface) {
                status = omapi_object_type_register
@@ -113,6 +114,7 @@ void discover_interfaces (state)
                log_fatal ("Can't create addrlist socket");
 
        /* Get the interface configuration information... */
+      gifconf_again:
        ic.ifc_len = sizeof buf;
        ic.ifc_ifcu.ifcu_buf = (caddr_t)buf;
        i = ioctl(sock, SIOCGIFCONF, &ic);
@@ -120,6 +122,16 @@ void discover_interfaces (state)
        if (i < 0)
                log_fatal ("ioctl: SIOCGIFCONF: %m");
 
+       /* If the SIOCGIFCONF resulted in more data than would fit in
+          a buffer, allocate a bigger buffer. */
+       if (ic.ifc_ifcu.ifcu_buf == buf &&
+           ic.ifc_len > sizeof buf) {
+               ic.ifc_ifcu.ifcu_buf = dmalloc ((size_t)ic.ifc_len, MDL);
+               if (!ic.ifc_ifcu.ifcu_buf)
+                       log_fatal ("Can't allocate SIOCGIFCONF buffer.");
+               goto gifconf_again;
+       }
+               
        /* If we already have a list of interfaces, and we're running as
           a DHCP server, the interfaces were requested. */
        if (interfaces && (state == DISCOVER_SERVER ||
@@ -261,6 +273,10 @@ void discover_interfaces (state)
                }
        }
 
+       /* If we allocated a buffer, free it. */
+       if (ic.ifc_ifcu.ifcu_buf != buf)
+               dfree (ic.ifc_ifcu.ifcu_buf, MDL);
+
 #if defined (LINUX_SLASHPROC_DISCOVERY)
        /* On Linux, interfaces that don't have IP addresses don't
           show up in the SIOCGIFCONF syscall.  This only matters for
@@ -487,6 +503,7 @@ void discover_interfaces (state)
 
                /* We must have a subnet declaration for each interface. */
                if (!tmp -> shared_network && (state == DISCOVER_SERVER)) {
+                       log_error ("%s", "");
                        log_error ("No subnet declaration for %s (%s).",
                                   tmp -> name, inet_ntoa (foo.sin_addr));
                        if (supports_multiple_interfaces (tmp)) {
@@ -530,6 +547,7 @@ void discover_interfaces (state)
                /* Register the interface... */
                if_register_receive (tmp);
                if_register_send (tmp);
+               wifcount++;
 #if defined (HAVE_SETFD)
                if (fcntl (tmp -> rfdesc, F_SETFD, 1) < 0)
                        log_error ("Can't set close-on-exec on %s: %m",
@@ -561,6 +579,11 @@ void discover_interfaces (state)
 
        close (sock);
 
+       if (state == DISCOVER_SERVER && wifcount == 0) {
+               log_info ("%s", "");
+               log_fatal ("Not configured to listen on any interfaces!");
+       }
+
        if (!setup_fallback) {
                setup_fallback = 1;
                maybe_setup_fallback ();