ifupdown: allow duplicate interface definitions

This patch allow to have multiple interface definitions, much like
Debian's ifupdown.  More specifically, it removes the check for a
duplicate definition, so the impact on binary size should be fairly
minimal.

This configuration:

iface eth0 inet static
        address 192.168.0.15
        netmask 255.255.0.0
        gateway 192.168.0.1

iface eth0 inet static
        address 10.0.0.1
        netmask 255.255.255.0

Will add two addresses to eth0 if ip is used.  If ifconfig is used,
the standards methods will likely not stack, but the administrator may
still use the manual method.  The DHCP method may work depending on the
DHCP client in use.

This is a fairly advanced feature for power users who knows what they
are doing.  There are not many other network configuration systems that
allows multiple addresses on an interface.

Signed-off-by: Nicolas Cavallari <nicolas.cavallari@green-communications.fr>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

diff --git a/networking/ifupdown.c b/networking/ifupdown.c
index 766dfabbd05662e7530d606b33372a75cee69a92..179186199c624c3d4d5146e3f084ce32f070ced7 100644 (file)
--- a/networking/ifupdown.c
+++ b/networking/ifupdown.c
@@ -875,7 +875,19 @@ static struct interfaces_file_t *read_interfaces(const char *filename, struct in
                        currif->method = get_method(currif->address_family, method_name);
                        if (!currif->method)
                                bb_error_msg_and_die("unknown method \"%s\"", method_name);
-
+#if 0
+// Allegedly, Debian allows a duplicate definition:
+// iface eth0 inet static
+//     address 192.168.0.15
+//     netmask 255.255.0.0
+//     gateway 192.168.0.1
+//
+// iface eth0 inet static
+//     address 10.0.0.1
+//     netmask 255.255.255.0
+//
+// This adds *two* addresses to eth0 (probably requires use of "ip", not "ifconfig"
+//
                        for (iface_list = defn->ifaces; iface_list; iface_list = iface_list->link) {
                                struct interface_defn_t *tmp = (struct interface_defn_t *) iface_list->data;
                                if ((strcmp(tmp->iface, currif->iface) == 0)
@@ -884,6 +896,7 @@ static struct interfaces_file_t *read_interfaces(const char *filename, struct in
                                        bb_error_msg_and_die("duplicate interface \"%s\"", tmp->iface);
                                }
                        }
+#endif
                        llist_add_to_end(&(defn->ifaces), (char*)currif);
 
                        debug_noise("iface %s %s %s\n", currif->iface, address_family_name, method_name);