B.A.T.M.A.N

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[B.A.T.M.A.N.] [PATCH 1/2] batman-adv: Make orig_node->router an rcu protected pointer
by Linus Lüssing 06 Mar '11

06 Mar '11

The rcu protected macros rcu_dereference() and rcu_assign_pointer() for the orig_node->router need to be used, as well as spin/rcu locking. Otherwise we might end up using a router pointer pointing to already freed memory. In update_orig() the functions update_route_rcu() (former update_route()) and update_HNA() are now called directly instead of update_routes() in both cases. This made keeping the rcu-locking neat easier update_routes() would have called the according functions at these positions always anyway. Also two small code blocks in receive_bat_packet() were swapped to keep the time for rcu-locking low. Signed-off-by: Linus Lüssing <linus.luessing(a)web.de> --- gateway_client.c | 39 +++++++++++-------- icmp_socket.c | 2 +- originator.c | 6 +- routing.c | 110 ++++++++++++++++++++++++++++++++---------------------- types.h | 4 +- 5 files changed, 93 insertions(+), 68 deletions(-) diff --git a/gateway_client.c b/gateway_client.c index 3cc4355..de57936 100644 --- a/gateway_client.c +++ b/gateway_client.c @@ -97,6 +97,7 @@ void gw_election(struct bat_priv *bat_priv) { struct hlist_node *node; struct gw_node *gw_node, *curr_gw, *curr_gw_tmp = NULL; + struct neigh_node *router; uint8_t max_tq = 0; uint32_t max_gw_factor = 0, tmp_gw_factor = 0; int down, up; @@ -132,7 +133,8 @@ void gw_election(struct bat_priv *bat_priv) } hlist_for_each_entry_rcu(gw_node, node, &bat_priv->gw_list, list) { - if (!gw_node->orig_node->router) + router = rcu_dereference(gw_node->orig_node->router); + if (!router) continue; if (gw_node->deleted) @@ -143,15 +145,14 @@ void gw_election(struct bat_priv *bat_priv) gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up); - tmp_gw_factor = (gw_node->orig_node->router->tq_avg * - gw_node->orig_node->router->tq_avg * + tmp_gw_factor = (router->tq_avg * router->tq_avg * down * 100 * 100) / (TQ_LOCAL_WINDOW_SIZE * TQ_LOCAL_WINDOW_SIZE * 64); if ((tmp_gw_factor > max_gw_factor) || ((tmp_gw_factor == max_gw_factor) && - (gw_node->orig_node->router->tq_avg > max_tq))) + (router->tq_avg > max_tq))) curr_gw_tmp = gw_node; break; @@ -163,19 +164,20 @@ void gw_election(struct bat_priv *bat_priv) * soon as a better gateway appears which has * $routing_class more tq points) **/ - if (gw_node->orig_node->router->tq_avg > max_tq) + if (router->tq_avg > max_tq) curr_gw_tmp = gw_node; break; } - if (gw_node->orig_node->router->tq_avg > max_tq) - max_tq = gw_node->orig_node->router->tq_avg; + if (router->tq_avg > max_tq) + max_tq = router->tq_avg; if (tmp_gw_factor > max_gw_factor) max_gw_factor = tmp_gw_factor; } if (curr_gw != curr_gw_tmp) { + router = rcu_dereference(curr_gw_tmp->orig_node->router); if ((curr_gw) && (!curr_gw_tmp)) bat_dbg(DBG_BATMAN, bat_priv, "Removing selected gateway - " @@ -186,14 +188,14 @@ void gw_election(struct bat_priv *bat_priv) "(gw_flags: %i, tq: %i)\n", curr_gw_tmp->orig_node->orig, curr_gw_tmp->orig_node->gw_flags, - curr_gw_tmp->orig_node->router->tq_avg); + router->tq_avg); else bat_dbg(DBG_BATMAN, bat_priv, "Changing route to gateway %pM " "(gw_flags: %i, tq: %i)\n", curr_gw_tmp->orig_node->orig, curr_gw_tmp->orig_node->gw_flags, - curr_gw_tmp->orig_node->router->tq_avg); + router->tq_avg); gw_select(bat_priv, curr_gw_tmp); } @@ -204,6 +206,7 @@ void gw_election(struct bat_priv *bat_priv) void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node) { struct gw_node *curr_gateway_tmp; + struct neigh_node *router; uint8_t gw_tq_avg, orig_tq_avg; rcu_read_lock(); @@ -214,20 +217,21 @@ void gw_check_election(struct bat_priv *bat_priv, struct orig_node *orig_node) if (!curr_gateway_tmp->orig_node) goto deselect_rcu; - if (!curr_gateway_tmp->orig_node->router) + router = rcu_dereference(curr_gateway_tmp->orig_node->router); + if (!router) goto deselect_rcu; /* this node already is the gateway */ if (curr_gateway_tmp->orig_node == orig_node) goto out_rcu; - if (!orig_node->router) + if (!rcu_dereference(orig_node->router)) goto out_rcu; - gw_tq_avg = curr_gateway_tmp->orig_node->router->tq_avg; + gw_tq_avg = router->tq_avg; + orig_tq_avg = rcu_dereference(orig_node->router)->tq_avg; rcu_read_unlock(); - orig_tq_avg = orig_node->router->tq_avg; /* the TQ value has to be better */ if (orig_tq_avg < gw_tq_avg) @@ -365,19 +369,20 @@ static int _write_buffer_text(struct bat_priv *bat_priv, struct seq_file *seq, struct gw_node *gw_node) { struct gw_node *curr_gw; + struct neigh_node *router; int down, up, ret; gw_bandwidth_to_kbit(gw_node->orig_node->gw_flags, &down, &up); rcu_read_lock(); curr_gw = rcu_dereference(bat_priv->curr_gw); + router = rcu_dereference(gw_node->orig_node->router); ret = seq_printf(seq, "%s %pM (%3i) %pM [%10s]: %3i - %i%s/%i%s\n", (curr_gw == gw_node ? "=>" : " "), gw_node->orig_node->orig, - gw_node->orig_node->router->tq_avg, - gw_node->orig_node->router->addr, - gw_node->orig_node->router->if_incoming->net_dev->name, + router->tq_avg, router->addr, + router->if_incoming->net_dev->name, gw_node->orig_node->gw_flags, (down > 2048 ? down / 1024 : down), (down > 2048 ? "MBit" : "KBit"), @@ -422,7 +427,7 @@ int gw_client_seq_print_text(struct seq_file *seq, void *offset) if (gw_node->deleted) continue; - if (!gw_node->orig_node->router) + if (!rcu_dereference(gw_node->orig_node->router)) continue; _write_buffer_text(bat_priv, seq, gw_node); diff --git a/icmp_socket.c b/icmp_socket.c index 34ce56c..3000c6b 100644 --- a/icmp_socket.c +++ b/icmp_socket.c @@ -224,7 +224,7 @@ static ssize_t bat_socket_write(struct file *file, const char __user *buff, if (!orig_node) goto unlock; - neigh_node = orig_node->router; + neigh_node = rcu_dereference(orig_node->router); if (!neigh_node) goto unlock; diff --git a/originator.c b/originator.c index 0b91330..31c6b5a 100644 --- a/originator.c +++ b/originator.c @@ -421,10 +421,11 @@ int orig_seq_print_text(struct seq_file *seq, void *offset) rcu_read_lock(); hlist_for_each_entry_rcu(orig_node, node, head, hash_entry) { - if (!orig_node->router) + neigh_node = rcu_dereference(orig_node->router); + if (!neigh_node) continue; - if (orig_node->router->tq_avg == 0) + if (neigh_node->tq_avg == 0) continue; last_seen_secs = jiffies_to_msecs(jiffies - @@ -432,7 +433,6 @@ int orig_seq_print_text(struct seq_file *seq, void *offset) last_seen_msecs = jiffies_to_msecs(jiffies - orig_node->last_valid) % 1000; - neigh_node = orig_node->router; seq_printf(seq, "%pM %4i.%03is (%3i) %pM [%10s]:", orig_node->orig, last_seen_secs, last_seen_msecs, neigh_node->tq_avg, diff --git a/routing.c b/routing.c index c172f5d..db4f72c 100644 --- a/routing.c +++ b/routing.c @@ -82,15 +82,17 @@ static void update_HNA(struct bat_priv *bat_priv, struct orig_node *orig_node, } } -static void update_route(struct bat_priv *bat_priv, - struct orig_node *orig_node, - struct neigh_node *neigh_node, - unsigned char *hna_buff, int hna_buff_len) +static void update_route_rcu(struct bat_priv *bat_priv, + struct orig_node *orig_node, + struct neigh_node *neigh_node, + unsigned char *hna_buff, int hna_buff_len) { struct neigh_node *neigh_node_tmp; + neigh_node_tmp = rcu_dereference(orig_node->router); + /* route deleted */ - if ((orig_node->router) && (!neigh_node)) { + if ((neigh_node_tmp) && (!neigh_node)) { bat_dbg(DBG_ROUTES, bat_priv, "Deleting route towards: %pM\n", orig_node->orig); @@ -98,7 +100,7 @@ static void update_route(struct bat_priv *bat_priv, "originator timed out"); /* route added */ - } else if ((!orig_node->router) && (neigh_node)) { + } else if ((!neigh_node_tmp) && (neigh_node)) { bat_dbg(DBG_ROUTES, bat_priv, "Adding route towards: %pM (via %pM)\n", @@ -112,13 +114,16 @@ static void update_route(struct bat_priv *bat_priv, "Changing route towards: %pM " "(now via %pM - was via %pM)\n", orig_node->orig, neigh_node->addr, - orig_node->router->addr); + neigh_node_tmp->addr); } if (neigh_node && !atomic_inc_not_zero(&neigh_node->refcount)) neigh_node = NULL; - neigh_node_tmp = orig_node->router; - orig_node->router = neigh_node; + + spin_lock_bh(&orig_node->neigh_list_lock); + rcu_assign_pointer(orig_node->router, neigh_node); + spin_unlock_bh(&orig_node->neigh_list_lock); + if (neigh_node_tmp) neigh_node_free_ref(neigh_node_tmp); } @@ -132,12 +137,17 @@ void update_routes(struct bat_priv *bat_priv, struct orig_node *orig_node, if (!orig_node) return; - if (orig_node->router != neigh_node) - update_route(bat_priv, orig_node, neigh_node, - hna_buff, hna_buff_len); + rcu_read_lock(); + if (rcu_dereference(orig_node->router) != neigh_node) { + update_route_rcu(bat_priv, orig_node, neigh_node, + hna_buff, hna_buff_len); + rcu_read_unlock(); + } /* may be just HNA changed */ - else + else { + rcu_read_unlock(); update_HNA(bat_priv, orig_node, hna_buff, hna_buff_len); + } } static int is_bidirectional_neigh(struct orig_node *orig_node, @@ -298,10 +308,12 @@ static void bonding_candidate_add(struct orig_node *orig_node, neigh_node->orig_node->primary_addr)) goto candidate_del; - if (!orig_node->router) + rcu_read_lock(); + if (!rcu_dereference(orig_node->router)) goto candidate_del; - best_tq = orig_node->router->tq_avg; + best_tq = rcu_dereference(orig_node->router)->tq_avg; + rcu_read_unlock(); /* ... and is good enough to be considered */ if (neigh_node->tq_avg < best_tq - BONDING_TQ_THRESHOLD) @@ -372,7 +384,7 @@ static void update_orig(struct bat_priv *bat_priv, unsigned char *hna_buff, int hna_buff_len, char is_duplicate) { - struct neigh_node *neigh_node = NULL, *tmp_neigh_node = NULL; + struct neigh_node *neigh_node = NULL, *tmp_neigh_node = NULL, *router; struct orig_node *orig_node_tmp; struct hlist_node *node; int tmp_hna_buff_len; @@ -441,19 +453,20 @@ static void update_orig(struct bat_priv *bat_priv, /* if this neighbor already is our next hop there is nothing * to change */ - if (orig_node->router == neigh_node) + rcu_read_lock(); + router = rcu_dereference(orig_node->router); + if (router == neigh_node) goto update_hna; /* if this neighbor does not offer a better TQ we won't consider it */ - if ((orig_node->router) && - (orig_node->router->tq_avg > neigh_node->tq_avg)) + if ((router) && (router->tq_avg > neigh_node->tq_avg)) goto update_hna; /* if the TQ is the same and the link not more symetric we * won't consider it either */ - if ((orig_node->router) && - (neigh_node->tq_avg == orig_node->router->tq_avg)) { - orig_node_tmp = orig_node->router->orig_node; + if ((router) && + (neigh_node->tq_avg == router->tq_avg)) { + orig_node_tmp = router->orig_node; spin_lock_bh(&orig_node_tmp->ogm_cnt_lock); bcast_own_sum_orig = orig_node_tmp->bcast_own_sum[if_incoming->if_num]; @@ -469,13 +482,15 @@ static void update_orig(struct bat_priv *bat_priv, goto update_hna; } - update_routes(bat_priv, orig_node, neigh_node, - hna_buff, tmp_hna_buff_len); + update_route_rcu(bat_priv, orig_node, neigh_node, + hna_buff, tmp_hna_buff_len); + rcu_read_unlock(); + goto update_gw; update_hna: - update_routes(bat_priv, orig_node, orig_node->router, - hna_buff, tmp_hna_buff_len); + rcu_read_unlock(); + update_HNA(bat_priv, orig_node, hna_buff, hna_buff_len); update_gw: if (orig_node->gw_flags != batman_packet->gw_flags) @@ -603,6 +618,7 @@ void receive_bat_packet(struct ethhdr *ethhdr, struct bat_priv *bat_priv = netdev_priv(if_incoming->soft_iface); struct hard_iface *hard_iface; struct orig_node *orig_neigh_node, *orig_node; + struct neigh_node *router; char has_directlink_flag; char is_my_addr = 0, is_my_orig = 0, is_my_oldorig = 0; char is_broadcast = 0, is_bidirectional, is_single_hop_neigh; @@ -748,18 +764,30 @@ void receive_bat_packet(struct ethhdr *ethhdr, } /* avoid temporary routing loops */ - if ((orig_node->router) && - (orig_node->router->orig_node->router) && - (compare_eth(orig_node->router->addr, - batman_packet->prev_sender)) && + rcu_read_lock(); + router = rcu_dereference(orig_node->router); + if ((router) && + (rcu_dereference(router->orig_node->router)) && + (compare_eth(router->addr, batman_packet->prev_sender)) && !(compare_eth(batman_packet->orig, batman_packet->prev_sender)) && - (compare_eth(orig_node->router->addr, - orig_node->router->orig_node->router->addr))) { + (compare_eth(router->addr, + rcu_dereference(router->orig_node->router)->addr))) { bat_dbg(DBG_BATMAN, bat_priv, "Drop packet: ignoring all rebroadcast packets that " "may make me loop (sender: %pM)\n", ethhdr->h_source); + rcu_read_unlock(); + goto out; + } + + /* drop packet if sender is not a direct neighbor and if we + * don't route towards it */ + if (!is_single_hop_neigh && !router) { + bat_dbg(DBG_BATMAN, bat_priv, + "Drop packet: OGM via unknown neighbor!\n"); + rcu_read_unlock(); goto out; } + rcu_read_unlock(); /* if sender is a direct neighbor the sender mac equals * originator mac */ @@ -769,14 +797,6 @@ void receive_bat_packet(struct ethhdr *ethhdr, if (!orig_neigh_node) goto out; - /* drop packet if sender is not a direct neighbor and if we - * don't route towards it */ - if (!is_single_hop_neigh && (!orig_neigh_node->router)) { - bat_dbg(DBG_BATMAN, bat_priv, - "Drop packet: OGM via unknown neighbor!\n"); - goto out_neigh; - } - is_bidirectional = is_bidirectional_neigh(orig_node, orig_neigh_node, batman_packet, if_incoming); @@ -892,7 +912,7 @@ static int recv_my_icmp_packet(struct bat_priv *bat_priv, if (!orig_node) goto unlock; - neigh_node = orig_node->router; + neigh_node = rcu_dereference(orig_node->router); if (!neigh_node) goto unlock; @@ -958,7 +978,7 @@ static int recv_icmp_ttl_exceeded(struct bat_priv *bat_priv, if (!orig_node) goto unlock; - neigh_node = orig_node->router; + neigh_node = rcu_dereference(orig_node->router); if (!neigh_node) goto unlock; @@ -1056,7 +1076,7 @@ int recv_icmp_packet(struct sk_buff *skb, struct hard_iface *recv_if) if (!orig_node) goto unlock; - neigh_node = orig_node->router; + neigh_node = rcu_dereference(orig_node->router); if (!neigh_node) goto unlock; @@ -1117,8 +1137,8 @@ struct neigh_node *find_router(struct bat_priv *bat_priv, rcu_read_lock(); /* select default router to output */ - router = orig_node->router; - router_orig = orig_node->router->orig_node; + router = rcu_dereference(orig_node->router); + router_orig = router->orig_node; if (!router_orig || !atomic_inc_not_zero(&router->refcount)) { rcu_read_unlock(); return NULL; diff --git a/types.h b/types.h index 83445cf..1854cbb 100644 --- a/types.h +++ b/types.h @@ -67,7 +67,7 @@ struct hard_iface { struct orig_node { uint8_t orig[ETH_ALEN]; uint8_t primary_addr[ETH_ALEN]; - struct neigh_node *router; + struct neigh_node __rcu *router; /* rcu protected pointer */ unsigned long *bcast_own; uint8_t *bcast_own_sum; unsigned long last_valid; @@ -83,7 +83,7 @@ struct orig_node { uint32_t last_bcast_seqno; struct hlist_head neigh_list; struct list_head frag_list; - spinlock_t neigh_list_lock; /* protects neighbor list */ + spinlock_t neigh_list_lock; /* protects neigh_list and router */ atomic_t refcount; struct rcu_head rcu; struct hlist_node hash_entry; -- 1.7.4.1

1 4

[B.A.T.M.A.N.] Null pointer dereference, ticket #146
by Linus Lüssing 04 Mar '11

04 Mar '11

Hi everyone, By accident I've typed in a mesh interface name for batman-adv which already existed as a real interface. This produces a null pointer dereference in orig_hash_add_if(): http://www.open-mesh.org/ticket/146 The attached patch shall illustrate the problem, but I'm not quite satisfied with it. Although it seems to "fix" the problem and gets rid of the call trace, it is probably still very racy. Does anyone have an idea for a more sane but equally easy check to fix the issue? Or is the only sane solution to hold an rcu-lock and compare the hard_iface->soft_iface in hardif_enable_interface() with every hard-iface->net_dev from the hardif_list? Cheers, Linus

4 8

[B.A.T.M.A.N.] [PATCH] batman-adv: orig_node must be freed after in case of timeout
by Antonio Quartulli 04 Mar '11

04 Mar '11

This patch corrects commit 4c4236064501e85915087f00a370df8d9f43028d in which bucket_free_orig_rcu() has been removed but without being replaced. In _push_orig(), the orig_node was not freed anymore after a timeout. Signed-off-by: Sven Eckelmann <sven(a)narfation.org> Signed-off-by: Marek Lindner <lindner_marek(a)yahoo.de> --- originator.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/originator.c b/originator.c index 53753d3..0b91330 100644 --- a/originator.c +++ b/originator.c @@ -349,6 +349,7 @@ static void _purge_orig(struct bat_priv *bat_priv) if (orig_node->gw_flags) gw_node_delete(bat_priv, orig_node); hlist_del_rcu(node); + orig_node_free_ref(orig_node); continue; } -- 1.7.3.4

2 1

[B.A.T.M.A.N.] Wireless Battle Mesh v4 - Agenda
by Marek Lindner 04 Mar '11

04 Mar '11

Wireless Battle Mesh v4 - Agenda ===================== The principal assembly work on the WBMv4 agenda has been completed and the result published on the battlemesh website: http://battlemesh.org/BattleMeshV4/Agenda However, expect some minor tweaks in the coming days as we always have some latecomers. The most difficult part while compiling the schedule was the various travel plans of the speakers. If any speaker feels uneasy about its talk feel free to contact me - a solution will be found. Lightening talks: These slots can be acquired by simply contacting me during the event. The agenda will be updated as soon as slots have been registered. If you have any question or suggestion, please let me know. Regards, Marek

1 0

[B.A.T.M.A.N.] Redundancy bonding mode patches, v2
by Linus Lüssing 03 Mar '11

03 Mar '11

Hi everyone, Here are some smaller modifications of the redundancy bonding mode patches. I haven't modified the batman_header yet, as there seem to be some other opinions about this, too and might be easier to discuss at the WBMv4. As always, everything is available here as well: http://git.open-mesh.org/?p=t_x/batman-adv.git;a=shortlog;h=refs/heads/rbon… Cheers, Linus rbonding changelog v2: * Fix (interim) refcounting bug / memory leak in unicast_send_skb() [5/12] * change recv_icmp_ttl_exceeded() to change_icmp_ttl_exceeded(), as it is in the sending code path now (thanks Andrew!) [3/12] * Add missing ttl modification in aggregation.c [3/12] * rebased to f39fe6f230e4cbf2b04e659b056ea62a652578a0

2 16

[B.A.T.M.A.N.] OGM overhead and routing metric proposal
by Daniele Furlan 01 Mar '11

01 Mar '11

Hi all, as promised, I have completed the analysis of the protocol overhead providing also simulation results with and whitout the OGM aggregation mechanism activated. As anticipated the results shows that aggregation works well in reducing the overhead. In attachment the report (OGMoverhead.pdf). In attachment you will also find a draft/proposals of a new routing approach. It is based on the collection of more link parameters (the current TQ, bit-rate and node-load) to write in OGM at each hop. This permit to develop a more thorough metric and can open new room of improvement such multi-path routing. Any comment/suggestion is welcome! Regards. -- Daniele Furlan

3 7

[B.A.T.M.A.N.] batman-adv mesh slows down wired clients (bridge-loop-avoidance)
by Vinay Tharigopula 01 Mar '11

01 Mar '11

Hello.. I succesfully configured a batman-adv mesh to add access points to our existing wired lan. I am using Openwrt 10.04 and batman-adv 2010.1.0. DHCP and everything works as expected. Any wired or wireless client connecting to the network gets an IP from a DHCP server hooked into the switch etc etc. Our Network configuration: 8 batman-adv routers with a wireless mesh with two or more of the routers having a wired connection directly to the switch. In this case, the 8 routers decide to pick one of the "plugged in" routers as a gateway to avoid bridge loops. This is fine. I have been running into issues with wired clients however. When a wired client plugged into the switch tries to contact a wired client plugged into the same switch, the packets manage to get lost. I believe they are are going through the wireless routers plugged into the same switch. Instead of going like this.. PC 1 ----> switch1 ---> PC 2 they seem to be going like this... (my guess). PC 1 ---> switch1 ---> wireless router 1 ----(wireless mesh link)----> wireless router 2 ----> switch1 ---> PC 2. I think this is because the translation tables on the bat node are announcing that even the wired clients are connected to them. This is causing extreme delays even in wired clients. Any help will be appreciated. Should I enable STP in on the switch ports ? - Vinay

3 11

Re: [B.A.T.M.A.N.] BATMAN routing
by Sven Eckelmann 28 Feb '11

28 Feb '11

On Monday 28 February 2011 20:15:05 hlabishi kobo wrote: > Thanks again for your reply sven, but i think my code might have maybe > you a different view of wht i want to do, see below. > The idea is to prioritize recently received OGM's thus giving them > more weight for the routing decisions. suppose you have sliding window > of 10, a link A records [1111100000]= 5 and link B records > [0000001111] = 4, currently this will be used towards the calculation > of local TQ. in the proposed method we want to add the indexes on > which an OGM was received in that interval. from the example above we > would have link A 1+2+3+4+5+6= 21 and link B 7+8+9+10 = 34. this > actually what i meant by counting and adding indexes. I know what you want, but it seems (judging from your "implementation") that you don't know how to write that down. I hope that I gave you enough information to show you why your implementation isn't what you want. The last part should help you to implement it the right way and to understand what the values represent and how you should operate on them. Best regards, Sven

1 0

[B.A.T.M.A.N.] Fwd: BATMAN routing
by hlabishi kobo 28 Feb '11

28 Feb '11

---------- Forwarded message ---------- From: hlabishi kobo <hlabishik(a)gmail.com> Date: Sun, 28 Nov 2010 22:06:01 +0200 Subject: Fwd: BATMAN routing To: lindner_marek(a)yahoo.de Hi Thank you very much for your reply. The reason why i sent this to you and your colleague is that i have tried the mail list before and all my post kept on being returned, i used this address b.a.t.m.a.n-owner(a)lists.open-mesh.org. I would really appreciate it if this can reach the mailing list public (i will keep on trying). i will send you a follow up on the full explanation of the concept like you requested. Regards Hlabishi ---------- Forwarded message ---------- From: <b.a.t.m.a.n-owner(a)lists.open-mesh.org> Date: Sat, Nov 27, 2010 at 12:58 AM Subject: Fwd: BATMAN routing To: hlabishik(a)gmail.com Message rejected by filter rule match ---------- Forwarded message ---------- From: hlabishi kobo <hlabishik(a)gmail.com> To: b.a.t.m.a.n(a)lists.open-mesh.org Date: Sat, 27 Nov 2010 00:58:09 +0200 Subject: Fwd: BATMAN routing ---------- Forwarded message ---------- From: Marek Lindner <lindner_marek(a)yahoo.de> Date: Fri, Nov 26, 2010 at 5:23 PM Subject: Re: BATMAN routing To: hlabishi kobo <hlabishik(a)gmail.com>, Linus Lüssing < linus.luessing(a)web.de> Cc: siwu(a)hrz.tu-chemnitz.de Hi, welcome to the project! :-) > Firstly my apologies for sending this email to your personal email. My name > is Hlabishi Isaac Kobo at the, an Msc computer science student at the > University of the Western Cape in South Africa, I am doing a research on > routing in a hybrid (combination of static and mobile dynamic routers) > mesh. I don't see a good reason to apologize, just wondering why you are not sending this mail to the public list ? > I want to use the mesh potatoes as well as the batphone (android > version of batman) to create a mesh model. What is the "batphone" ? A project name or a nick name you invented ? :-) Note: Various tests have shown that running a mobile device (smartphone/tablet/etc) in adhoc mode plus running a mesh protocol on top is a battery killer, hence not practical in real world scenarios (in addition of the hassle to install and configure the mesh software on each and every device). This was one of the main reasons to start developing batman-adv as it allows mobile devices to take advantage of the mesh (e.g. roaming) without having to run the mesh on the device itself. You might be aware of this - I am just mentioning it because many people are not. > First we say the recently received OGMs will give a clear indication on the > reliability on the link, so we give the recently received OGMs from the > sliding window a priority in deciding the best next hop link towards a > destination. We want to count and add the indexes were an OGM was recorded > in an interval (seconds), (hence the recently received OGM will have more > weight). At the end the link with more recent OGMs will have more weight > and hence become the current best link. This is a good idea. We are in the process of redesigning the current protocol and welcome any input. Giving older OGMs less "weight" was also one of the ideas we had. Would you mind explaining your concept in greater detail ? > I went through the source code so many times and I got few questions about > this: Are we talking about the batman daemon source code or the batman-adv kernel module ? All my answers will refer to the kernel module as this is the place where most of the development is going on at the moment. > 1. What structure is used to keep track of the sliding window? If its the > has how does it get updated based on the sliding packet range? Each "struct orig_node" has a bitarray to keep track of its own seqnos repeated by its neighbors (bcast_own) and each "struct neigh_node" having a bitarray for its own OGMs (real_bits). > 2. How are the OGM's recorded, is in a form of binary where 1 will > represent the received OGM and 0 otherwise? Correct. > 3. I looked in the source and still not sure of where the ranking decisions > are made, can you enlighten me on that? You mean which function changes the route when a better neighbor was found ? That would be update_orig() in routing.c. > On the second approach we want to use mac layer stats to estimate the > signal strength and probably the congestion rate of the top N ranked links. > We acknowledge the fact that usually links with lower signal strength will > loose more OGM's which results in an automatic low rank, however in a > frequently changing topology, current signal strength is crucial. We plan > to use SNR or RSSI in this case. The concept is known since a while but nobody has implemented it so far because its implementation is fairly complex. Do you have an idea how it should work in the end ? > 1. How can i get the RSSI/LQI of th neighbor links? I don't get this question. You intend to use RSSI but you don't know how ? > I would really appreciate your opinions and advices in this regard more > specially how to go about implementing changes in BATMAN protocol. This is a little abstract. Usually, we discuss specific concepts / ideas in our IRC channel or on the mailing list long before starting to implement them. The past has shown it is often better to let other people dive into your ideas and comment because routing is a rather complex subject. As I mentioned above: We are in a redesign phase right now and welcome anyone interested to join. As the next step we envisioned a collection of routing scenarios in which the current implementation behaves poorly. All routing protocol changes have to go through this collection of scenarios to estimate its impact. What do you think about this idea ? Regards, Marek

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Re: [B.A.T.M.A.N.] batman-adv mesh slows down wired clients (bridge-loop-avoidance)
by Marek Lindner 26 Feb '11

26 Feb '11

Hi, Linus has some problems sending mails to the list, so I forward his reply. Cheers, Marek ============================================ Hi Vinay, On Fri, Feb 25, 2011 at 08:44:33AM -0500, Vinay Tharigopula wrote: > Marek.. > > I got the binaries from the openwrt prebuilt packages. However, > now > I rebuilt the image and built batman-adv 2011.myself. I will try > this now and let you know. > > However, now I am running into a much bigger issue. If two > routers > are plugged in to the same switch, bridge loop avoidance doesnt > work > and both of them are stopping responding to pings. Could you try "batctl ping" too and check whether this is working or not. If that's working but the normal pinging is not, then it should be a layer 3 problem - in that case we'd need the outputs of "ip route show" and "ip address show". If batctl ping is already not working then "batctl o" and "batctl if" output will be interesting. > > Here is my config. > > bat0 if: > wlan1: active. > > wlan1: Mesh Network. > > wlan0: Infrastructure network. > eth0 : 4 lan ports > eth1: 1 wan port > > br-lan : wlan0 eth0 eth1 bat0 Hmm, that looks sane and correct, should work like that. Is there anything weird in the output of "dmesg"? Any errors or warnings? Cheers, Linus

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