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author | Antonio Quartulli <ordex@autistici.org> | 2012-09-23 22:38:34 +0200 |
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committer | Antonio Quartulli <ordex@autistici.org> | 2012-11-14 21:00:35 +0100 |
commit | 7c1fd91da5a5eecc91674991199940c05f87cb3a (patch) | |
tree | 9195dbbe9ea99a09540166dd571779d9b7fde478 /net/batman-adv/routing.c | |
parent | batman-adv: wait multiple periods before activating bla (diff) | |
download | linux-7c1fd91da5a5eecc91674991199940c05f87cb3a.tar.xz linux-7c1fd91da5a5eecc91674991199940c05f87cb3a.zip |
batman-adv: substitute tt_poss_change with a per-tt_entry flag
tt_poss_change is a node-wide flag which tells whether the node is in a roaming
state (a client recently moved to/away from it) in order to let it apply special
re-routing rules. However this flag does not give a clear idea of the current
state because it is not possible to understand *which client* is actually
involved in the roaming. For this reason a better approach has been chosen:
instead of using a node-wide variable, the roaming state is now given by a
per-tt_entry ROAM flag which, in case of packet coming through the node, tells
the node whether the real destination is in roaming state or not.
With this flag change, batadv_check_unicast_ttvn() has also been rearranged in
order to better fit the new re-routing logic and to be much more readable.
Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Diffstat (limited to 'net/batman-adv/routing.c')
-rw-r--r-- | net/batman-adv/routing.c | 173 |
1 files changed, 122 insertions, 51 deletions
diff --git a/net/batman-adv/routing.c b/net/batman-adv/routing.c index 32aa4d460e1f..78d657264cbf 100644 --- a/net/batman-adv/routing.c +++ b/net/batman-adv/routing.c @@ -711,12 +711,6 @@ int batadv_recv_roam_adv(struct sk_buff *skb, struct batadv_hard_iface *recv_if) BATADV_TT_CLIENT_ROAM, atomic_read(&orig_node->last_ttvn) + 1); - /* Roaming phase starts: I have new information but the ttvn has not - * been incremented yet. This flag will make me check all the incoming - * packets for the correct destination. - */ - bat_priv->tt.poss_change = true; - batadv_orig_node_free_ref(orig_node); out: /* returning NET_RX_DROP will make the caller function kfree the skb */ @@ -899,14 +893,67 @@ out: return ret; } +/** + * batadv_reroute_unicast_packet - update the unicast header for re-routing + * @bat_priv: the bat priv with all the soft interface information + * @unicast_packet: the unicast header to be updated + * @dst_addr: the payload destination + * + * Search the translation table for dst_addr and update the unicast header with + * the new corresponding information (originator address where the destination + * client currently is and its known TTVN) + * + * Returns true if the packet header has been updated, false otherwise + */ +static bool +batadv_reroute_unicast_packet(struct batadv_priv *bat_priv, + struct batadv_unicast_packet *unicast_packet, + uint8_t *dst_addr) +{ + struct batadv_orig_node *orig_node = NULL; + struct batadv_hard_iface *primary_if = NULL; + bool ret = false; + uint8_t *orig_addr, orig_ttvn; + + if (batadv_is_my_client(bat_priv, dst_addr)) { + primary_if = batadv_primary_if_get_selected(bat_priv); + if (!primary_if) + goto out; + orig_addr = primary_if->net_dev->dev_addr; + orig_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn); + } else { + orig_node = batadv_transtable_search(bat_priv, NULL, dst_addr); + if (!orig_node) + goto out; + + if (batadv_compare_eth(orig_node->orig, unicast_packet->dest)) + goto out; + + orig_addr = orig_node->orig; + orig_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn); + } + + /* update the packet header */ + memcpy(unicast_packet->dest, orig_addr, ETH_ALEN); + unicast_packet->ttvn = orig_ttvn; + + ret = true; +out: + if (primary_if) + batadv_hardif_free_ref(primary_if); + if (orig_node) + batadv_orig_node_free_ref(orig_node); + + return ret; +} + static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv, struct sk_buff *skb) { - uint8_t curr_ttvn; + uint8_t curr_ttvn, old_ttvn; struct batadv_orig_node *orig_node; struct ethhdr *ethhdr; struct batadv_hard_iface *primary_if; struct batadv_unicast_packet *unicast_packet; - bool tt_poss_change; int is_old_ttvn; /* check if there is enough data before accessing it */ @@ -918,65 +965,89 @@ static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv, return 0; unicast_packet = (struct batadv_unicast_packet *)skb->data; + ethhdr = (struct ethhdr *)(skb->data + sizeof(*unicast_packet)); - if (batadv_is_my_mac(unicast_packet->dest)) { - tt_poss_change = bat_priv->tt.poss_change; - curr_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn); - } else { + /* check if the destination client was served by this node and it is now + * roaming. In this case, it means that the node has got a ROAM_ADV + * message and that it knows the new destination in the mesh to re-route + * the packet to + */ + if (batadv_tt_local_client_is_roaming(bat_priv, ethhdr->h_dest)) { + if (batadv_reroute_unicast_packet(bat_priv, unicast_packet, + ethhdr->h_dest)) + net_ratelimited_function(batadv_dbg, BATADV_DBG_TT, + bat_priv, + "Rerouting unicast packet to %pM (dst=%pM): Local Roaming\n", + unicast_packet->dest, + ethhdr->h_dest); + /* at this point the mesh destination should have been + * substituted with the originator address found in the global + * table. If not, let the packet go untouched anyway because + * there is nothing the node can do + */ + return 1; + } + + /* retrieve the TTVN known by this node for the packet destination. This + * value is used later to check if the node which sent (or re-routed + * last time) the packet had an updated information or not + */ + curr_ttvn = (uint8_t)atomic_read(&bat_priv->tt.vn); + if (!batadv_is_my_mac(unicast_packet->dest)) { orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->dest); - + /* if it is not possible to find the orig_node representing the + * destination, the packet can immediately be dropped as it will + * not be possible to deliver it + */ if (!orig_node) return 0; curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn); - tt_poss_change = orig_node->tt_poss_change; batadv_orig_node_free_ref(orig_node); } - /* Check whether I have to reroute the packet */ + /* check if the TTVN contained in the packet is fresher than what the + * node knows + */ is_old_ttvn = batadv_seq_before(unicast_packet->ttvn, curr_ttvn); - if (is_old_ttvn || tt_poss_change) { - /* check if there is enough data before accessing it */ - if (pskb_may_pull(skb, sizeof(struct batadv_unicast_packet) + - ETH_HLEN) < 0) - return 0; + if (!is_old_ttvn) + return 1; - ethhdr = (struct ethhdr *)(skb->data + sizeof(*unicast_packet)); + old_ttvn = unicast_packet->ttvn; + /* the packet was forged based on outdated network information. Its + * destination can possibly be updated and forwarded towards the new + * target host + */ + if (batadv_reroute_unicast_packet(bat_priv, unicast_packet, + ethhdr->h_dest)) { + net_ratelimited_function(batadv_dbg, BATADV_DBG_TT, bat_priv, + "Rerouting unicast packet to %pM (dst=%pM): TTVN mismatch old_ttvn=%u new_ttvn=%u\n", + unicast_packet->dest, ethhdr->h_dest, + old_ttvn, curr_ttvn); + return 1; + } - /* we don't have an updated route for this client, so we should - * not try to reroute the packet!! - */ - if (batadv_tt_global_client_is_roaming(bat_priv, - ethhdr->h_dest)) - return 1; + /* the packet has not been re-routed: either the destination is + * currently served by this node or there is no destination at all and + * it is possible to drop the packet + */ + if (!batadv_is_my_client(bat_priv, ethhdr->h_dest)) + return 0; - orig_node = batadv_transtable_search(bat_priv, NULL, - ethhdr->h_dest); - - if (!orig_node) { - if (!batadv_is_my_client(bat_priv, ethhdr->h_dest)) - return 0; - primary_if = batadv_primary_if_get_selected(bat_priv); - if (!primary_if) - return 0; - memcpy(unicast_packet->dest, - primary_if->net_dev->dev_addr, ETH_ALEN); - batadv_hardif_free_ref(primary_if); - } else { - memcpy(unicast_packet->dest, orig_node->orig, - ETH_ALEN); - curr_ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn); - batadv_orig_node_free_ref(orig_node); - } + /* update the header in order to let the packet be delivered to this + * node's soft interface + */ + primary_if = batadv_primary_if_get_selected(bat_priv); + if (!primary_if) + return 0; - net_ratelimited_function(batadv_dbg, BATADV_DBG_TT, bat_priv, - "TTVN mismatch (old_ttvn %u new_ttvn %u)! Rerouting unicast packet (for %pM) to %pM\n", - unicast_packet->ttvn, curr_ttvn, - ethhdr->h_dest, unicast_packet->dest); + memcpy(unicast_packet->dest, primary_if->net_dev->dev_addr, ETH_ALEN); + + batadv_hardif_free_ref(primary_if); + + unicast_packet->ttvn = curr_ttvn; - unicast_packet->ttvn = curr_ttvn; - } return 1; } |