Re: [B.A.T.M.A.N.] [PATCH 2/7] batman-adv: use vid when computing local and global TT CRC

On Wed, Apr 24, 2013 at 03:58:56AM +0800, Marek Lindner wrote:

On Tuesday, April 23, 2013 22:34:30 Antonio Quartulli wrote:

...

@@ -1535,7 +1535,9 @@ static uint32_t batadv_tt_global_crc(struct batadv_priv *bat_priv, orig_node)) continue;

•                   crc ^= crc32c(0, tt_common->addr, ETH_ALEN);
  

•                   crc_tmp = crc32c(0, &tt_common->vid,
  

•                                    sizeof(tt_common->vid));
  

•                   crc ^= crc32c(crc_tmp, tt_common->addr, ETH_ALEN);
            }
            rcu_read_unlock();
  

Is it necessary to define another variable ?

yes

Why not:

crc = crc32c(0, &tt_common->vid, sizeof(tt_common->vid)); crc ^= crc32c(crc, tt_common->addr, ETH_ALEN);

because crc_tmp is the result of the CRC operation on the VID and the MAC address (so one per client), while crc is the container of all the crc_tmp xor'ed together..

...

@@ -1565,7 +1567,9 @@ static uint32_t batadv_tt_local_crc(struct batadv_priv

*bat_priv)

...

                    if (tt_common->flags & BATADV_TT_CLIENT_NEW)
                            continue;

•                   crc ^= crc32c(0, tt_common->addr, ETH_ALEN);
  

•                   crc_tmp = crc32c(0, &tt_common->vid,
  

•                                    sizeof(tt_common->vid));
  

•                   crc ^= crc32c(crc_tmp, tt_common->addr, ETH_ALEN);
            }
  

Dito.

Idem.

Cheers,