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 --- originator.c | 1 - routing.c | 156 +++++++++++++++++++++++++++++++++++----------------- soft-interface.c | 1 - translation-table.c | 43 ++++++++++----- translation-table.h | 2 + types.h | 8 --- 6 files changed, 138 insertions(+), 73 deletions(-)
diff --git a/originator.c b/originator.c index d9c14b8..bf27edc 100644 --- a/originator.c +++ b/originator.c @@ -220,7 +220,6 @@ struct batadv_orig_node *batadv_get_orig_node(struct batadv_priv *bat_priv, atomic_set(&orig_node->refcount, 2);
orig_node->tt_initialised = false; - orig_node->tt_poss_change = false; orig_node->bat_priv = bat_priv; memcpy(orig_node->orig, addr, ETH_ALEN); orig_node->router = NULL; diff --git a/routing.c b/routing.c index 44109cc..bc4814c 100644 --- a/routing.c +++ b/routing.c @@ -710,12 +710,6 @@ 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 */ @@ -898,6 +892,46 @@ 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 + * @msg: the message to print explaining the reason of the requested re-route + * + * Search the global 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; + bool ret = false; + + 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; + + /* update the packet header */ + memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN); + unicast_packet->ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn); + + ret = true; +out: + 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; @@ -905,7 +939,6 @@ static int batadv_check_unicast_ttvn(struct batadv_priv *bat_priv, 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 */ @@ -917,65 +950,88 @@ 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)); + /* 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, + unicast_packet->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; }
diff --git a/soft-interface.c b/soft-interface.c index 22bc651..ffc0e16 100644 --- a/soft-interface.c +++ b/soft-interface.c @@ -488,7 +488,6 @@ struct net_device *batadv_softif_create(const char *name) #endif bat_priv->tt.last_changeset = NULL; bat_priv->tt.last_changeset_len = 0; - bat_priv->tt.poss_change = false;
bat_priv->primary_if = NULL; bat_priv->num_ifaces = 0; diff --git a/translation-table.c b/translation-table.c index a570d95..8227f99 100644 --- a/translation-table.c +++ b/translation-table.c @@ -306,8 +306,6 @@ void batadv_tt_local_add(struct net_device *soft_iface, const uint8_t *addr, head = &tt_global_entry->orig_list; rcu_read_lock(); hlist_for_each_entry_rcu(orig_entry, node, head, list) { - orig_entry->orig_node->tt_poss_change = true; - batadv_send_roam_adv(bat_priv, tt_global_entry->common.addr, orig_entry->orig_node); @@ -512,8 +510,11 @@ uint16_t batadv_tt_local_remove(struct batadv_priv *bat_priv, curr_flags = tt_local_entry->common.flags;
flags = BATADV_TT_CLIENT_DEL; - if (roaming) + if (roaming) { flags |= BATADV_TT_CLIENT_ROAM; + /* mark the local client as ROAMed */ + tt_local_entry->common.flags |= BATADV_TT_CLIENT_ROAM; + }
batadv_tt_local_set_pending(bat_priv, tt_local_entry, flags, message);
@@ -1996,10 +1997,6 @@ void batadv_handle_tt_response(struct batadv_priv *bat_priv,
/* Recalculate the CRC for this orig_node and store it */ orig_node->tt_crc = batadv_tt_global_crc(bat_priv, orig_node); - /* Roaming phase is over: tables are in sync again. I can - * unset the flag - */ - orig_node->tt_poss_change = false; out: if (orig_node) batadv_orig_node_free_ref(orig_node); @@ -2290,7 +2287,6 @@ static int batadv_tt_commit_changes(struct batadv_priv *bat_priv, batadv_dbg(BATADV_DBG_TT, bat_priv, "Local changes committed, updating to ttvn %u\n", (uint8_t)atomic_read(&bat_priv->tt.vn)); - bat_priv->tt.poss_change = false;
/* reset the sending counter */ atomic_set(&bat_priv->tt.ogm_append_cnt, BATADV_TT_OGM_APPEND_MAX); @@ -2402,11 +2398,6 @@ void batadv_tt_update_orig(struct batadv_priv *bat_priv, */ if (orig_node->tt_crc != tt_crc) goto request_table; - - /* Roaming phase is over: tables are in sync again. I can - * unset the flag - */ - orig_node->tt_poss_change = false; } else { /* if we missed more than one change or our tables are not * in sync anymore -> request fresh tt data @@ -2445,6 +2436,32 @@ out: return ret; }
+/** + * batadv_tt_local_client_is_roaming - tells whether the client is roaming + * @bat_priv: the bat priv with all the soft interface information + * @addr: the MAC address of the local client to query + * + * Returns true if the local client is known to be roaming (it is not served by + * this node anymore) or not. If yes, the client is still present in the table + * to keep the latter consistent with the node TTVN + */ +bool batadv_tt_local_client_is_roaming(struct batadv_priv *bat_priv, + uint8_t *addr) +{ + struct batadv_tt_local_entry *tt_local_entry; + bool ret = false; + + tt_local_entry = batadv_tt_local_hash_find(bat_priv, addr); + if (!tt_local_entry) + goto out; + + ret = !!(tt_local_entry->common.flags & BATADV_TT_CLIENT_ROAM); + batadv_tt_local_entry_free_ref(tt_local_entry); +out: + return ret; + +} + bool batadv_tt_add_temporary_global_entry(struct batadv_priv *bat_priv, struct batadv_orig_node *orig_node, const unsigned char *addr) diff --git a/translation-table.h b/translation-table.h index 9fa4fe4..46d4451 100644 --- a/translation-table.h +++ b/translation-table.h @@ -59,6 +59,8 @@ int batadv_tt_append_diff(struct batadv_priv *bat_priv, int packet_min_len); bool batadv_tt_global_client_is_roaming(struct batadv_priv *bat_priv, uint8_t *addr); +bool batadv_tt_local_client_is_roaming(struct batadv_priv *bat_priv, + uint8_t *addr); bool batadv_tt_add_temporary_global_entry(struct batadv_priv *bat_priv, struct batadv_orig_node *orig_node, const unsigned char *addr); diff --git a/types.h b/types.h index 02d5f50..e84da10 100644 --- a/types.h +++ b/types.h @@ -87,13 +87,6 @@ struct batadv_orig_node { spinlock_t tt_buff_lock; /* protects tt_buff */ atomic_t tt_size; bool tt_initialised; - /* The tt_poss_change flag is used to detect an ongoing roaming phase. - * If true, then I sent a Roaming_adv to this orig_node and I have to - * inspect every packet directed to it to check whether it is still - * the true destination or not. This flag will be reset to false as - * soon as I receive a new TTVN from this orig_node - */ - bool tt_poss_change; uint32_t last_real_seqno; uint8_t last_ttl; DECLARE_BITMAP(bcast_bits, BATADV_TQ_LOCAL_WINDOW_SIZE); @@ -191,7 +184,6 @@ struct batadv_priv_tt { atomic_t vn; atomic_t ogm_append_cnt; atomic_t local_changes; - bool poss_change; struct list_head changes_list; struct batadv_hashtable *local_hash; struct batadv_hashtable *global_hash;