[tipc-discussion] [PATCH] tipc: fix the big/little endian issue in tipc_dest

[Haiqing Bai]

In function tipc_dest_push, the 32bit variables 'node' and 'port'
are stored separately in uppper and lower part of 64bit 'value'.
Then this value is assigned to dst->value which is a union like:
union
{
  struct {
    u32 port;
    u32 node;
  };
  u64 value;
}
This works on little-endian machines like x86 but fails on big-endian
machines.

The fix remove the 'value' stack parameter and even the 'value'
member of the union in tipc_dest, assign the 'node' and 'port' member
directly with the input parameter to avoid the endian issue.

Signed-off-by: Zhenbo Gao <zhenbo....@windriver.com>
Signed-off-by: Haiqing Bai <haiqing....@windriver.com>
---
 net/tipc/name_table.c | 10 ++++------
 net/tipc/name_table.h |  9 ++-------
 2 files changed, 6 insertions(+), 13 deletions(-)

diff --git a/net/tipc/name_table.c b/net/tipc/name_table.c
index ed0457c..664c644 100644
--- a/net/tipc/name_table.c
+++ b/net/tipc/name_table.c
@@ -1117,20 +1117,17 @@ int tipc_nl_name_table_dump(struct sk_buff *skb, struct 
netlink_callback *cb)
 
 struct tipc_dest *tipc_dest_find(struct list_head *l, u32 node, u32 port)
 {
-       u64 value = (u64)node << 32 | port;
        struct tipc_dest *dst;
 
        list_for_each_entry(dst, l, list) {
-               if (dst->value != value)
-                       continue;
-               return dst;
+               if (dst->node == node && dst->port == port)
+                       return dst;
        }
        return NULL;
 }
 
 bool tipc_dest_push(struct list_head *l, u32 node, u32 port)
 {
-       u64 value = (u64)node << 32 | port;
        struct tipc_dest *dst;
 
        if (tipc_dest_find(l, node, port))
@@ -1139,7 +1136,8 @@ bool tipc_dest_push(struct list_head *l, u32 node, u32 
port)
        dst = kmalloc(sizeof(*dst), GFP_ATOMIC);
        if (unlikely(!dst))
                return false;
-       dst->value = value;
+       dst->node = node;
+       dst->port = port;
        list_add(&dst->list, l);
        return true;
 }
diff --git a/net/tipc/name_table.h b/net/tipc/name_table.h
index f56e7cb..2395408 100644
--- a/net/tipc/name_table.h
+++ b/net/tipc/name_table.h
@@ -127,13 +127,8 @@ void tipc_nametbl_stop(struct net *net);
 
 struct tipc_dest {
        struct list_head list;
-       union {
-               struct {
-                       u32 port;
-                       u32 node;
-               };
-               u64 value;
-       };
+       u32 port;
+       u32 node;
 };
 
 struct tipc_dest *tipc_dest_find(struct list_head *l, u32 node, u32 port);
-- 
1.9.1


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