[PATCH 2.6 NET] Fix ifmap alignment issues over rtnetlink

[Thomas Graf <tgraf@xxxxxxx>]

Introduces a fixed size variant for ifmap for rtnetlink. Fixes
issues with address size mismatch between kernel and userspace.
I couldn't find a better solution than using 64bit for memory
addresses and cast them in the kernel. Obviously this will fail
if userspace provides an address greater than 32bit.

Signed-off-by: Thomas Graf <tgraf@xxxxxxx>

Is it actually worth to keep trying to do this or should we just
declare that it's only possible via ethtool? Providing the
settings over rtnetlink is definitely a good thing in my eyes.

--- linux-2.6.9-rc2-bk7.orig/include/linux/rtnetlink.h  2004-09-21 
23:26:54.000000000 +0200
+++ linux-2.6.9-rc2-bk7/include/linux/rtnetlink.h       2004-09-21 
23:52:06.000000000 +0200
@@ -577,6 +577,17 @@
        __u32   tx_compressed;
 };
 
+/* The struct should be in sync with struct ifmap */
+struct rtnl_link_ifmap
+{
+       __u64   mem_start;
+       __u64   mem_end;
+       __u64   base_addr;
+       __u16   irq;
+       __u8    dma;
+       __u8    port;
+};
+
 enum
 {
        IFLA_UNSPEC,
--- linux-2.6.9-rc2-bk7.orig/net/core/rtnetlink.c       2004-09-21 
23:27:28.000000000 +0200
+++ linux-2.6.9-rc2-bk7/net/core/rtnetlink.c    2004-09-22 00:27:29.000000000 
+0200
@@ -182,7 +182,7 @@
        }
 
        if (1) {
-               struct ifmap map = {
+               struct rtnl_link_ifmap map = {
                        .mem_start   = dev->mem_start,
                        .mem_end     = dev->mem_end,
                        .base_addr   = dev->base_addr,
@@ -277,6 +277,9 @@
                dev_change_flags(dev, ifm->ifi_flags);
 
        if (ida[IFLA_MAP - 1]) {
+               struct rtnl_link_ifmap *u_map;
+               struct ifmap k_map;
+
                if (!dev->set_config) {
                        err = -EOPNOTSUPP;
                        goto out;
@@ -287,11 +290,19 @@
                        goto out;
                }
                
-               if (ida[IFLA_MAP - 1]->rta_len != RTA_LENGTH(sizeof(struct 
ifmap)))
+               if (ida[IFLA_MAP - 1]->rta_len != RTA_LENGTH(sizeof(*u_map)))
                        goto out;
-               
-               err = dev->set_config(dev, (struct ifmap *)
-                               RTA_DATA(ida[IFLA_MAP - 1]));
+
+               u_map = RTA_DATA(ida[IFLA_MAP - 1]);
+
+               k_map.mem_start = (unsigned long) u_map->mem_start;
+               k_map.mem_end = (unsigned long) u_map->mem_end;
+               k_map.base_addr = (unsigned short) u_map->base_addr;
+               k_map.irq = (unsigned char) u_map->irq;
+               k_map.dma = (unsigned char) u_map->dma;
+               k_map.port = (unsigned char) u_map->port;
+
+               err = dev->set_config(dev, (struct ifmap *) &k_map);
 
                if (err)
                        goto out;