From: Antonio Quartulli antonio@open-mesh.com
When computing the CRC on a 2byte variable the order of the bytes obviously alters the final result. This means that computing the CRC over the same value on two archs having different endianess leads to different numbers.
The global and local translation table CRC computation routine makes this mistake while processing the clients VIDs. The result is a continuous CRC mismatching between nodes having different endianess.
Fix this by converting the VID to Network Order before processing it. This guarantees that every node uses the same byte order.
Introduced by 7ea7b4a142758deaf46c1af0ca9ceca6dd55138b ("batman-adv: make the TT CRC logic VLAN specific")
Reported-by: Russel Senior russell@personaltelco.net Signed-off-by: Antonio Quartulli antonio@open-mesh.com Tested-by: Russell Senior russell@personaltelco.net Signed-off-by: Marek Lindner mareklindner@neomailbox.ch --- net/batman-adv/translation-table.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c index c21c557..959dde7 100644 --- a/net/batman-adv/translation-table.c +++ b/net/batman-adv/translation-table.c @@ -1975,6 +1975,7 @@ static uint32_t batadv_tt_global_crc(struct batadv_priv *bat_priv, struct hlist_head *head; uint32_t i, crc_tmp, crc = 0; uint8_t flags; + __be16 tmp_vid;
for (i = 0; i < hash->size; i++) { head = &hash->table[i]; @@ -2011,8 +2012,11 @@ static uint32_t batadv_tt_global_crc(struct batadv_priv *bat_priv, orig_node)) continue;
- crc_tmp = crc32c(0, &tt_common->vid, - sizeof(tt_common->vid)); + /* use network order to read the VID: this ensures that + * every node reads the bytes in the same order. + */ + tmp_vid = htons(tt_common->vid); + crc_tmp = crc32c(0, &tmp_vid, sizeof(tmp_vid));
/* compute the CRC on flags that have to be kept in sync * among nodes @@ -2046,6 +2050,7 @@ static uint32_t batadv_tt_local_crc(struct batadv_priv *bat_priv, struct hlist_head *head; uint32_t i, crc_tmp, crc = 0; uint8_t flags; + __be16 tmp_vid;
for (i = 0; i < hash->size; i++) { head = &hash->table[i]; @@ -2064,8 +2069,11 @@ static uint32_t batadv_tt_local_crc(struct batadv_priv *bat_priv, if (tt_common->flags & BATADV_TT_CLIENT_NEW) continue;
- crc_tmp = crc32c(0, &tt_common->vid, - sizeof(tt_common->vid)); + /* use network order to read the VID: this ensures that + * every node reads the bytes in the same order. + */ + tmp_vid = htons(tt_common->vid); + crc_tmp = crc32c(0, &tmp_vid, sizeof(tmp_vid));
/* compute the CRC on flags that have to be kept in sync * among nodes