A new function named prepare_unicast_packet() has been implemented so that it can do all the needed operations to set up a skb for unicast sending. It is general enough to be used in every context. Helpful for later developments

Signed-off-by: Antonio Quartulli ordex@autistici.org --- unicast.c | 48 ++++++++++++++++++++++++++++++++---------------- unicast.h | 2 ++ 2 files changed, 34 insertions(+), 16 deletions(-)

diff --git a/unicast.c b/unicast.c index 07d1c1d..ee7bceb 100644 --- a/unicast.c +++ b/unicast.c @@ -283,6 +283,33 @@ out: return ret; }

+struct sk_buff *prepare_unicast_packet(struct sk_buff *skb, + struct orig_node *orig_node) +{ + struct unicast_packet *unicast_packet; + + if (my_skb_head_push(skb, sizeof(*unicast_packet)) < 0) + goto out; + + unicast_packet = (struct unicast_packet *)skb->data; + + unicast_packet->version = COMPAT_VERSION; + /* batman packet type: unicast */ + unicast_packet->packet_type = BAT_UNICAST; + /* set unicast ttl */ + unicast_packet->ttl = TTL; + /* copy the destination for faster routing */ + memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN); + /* set the destination tt version number */ + unicast_packet->ttvn = + (uint8_t)atomic_read(&orig_node->last_ttvn); + + return skb; +out: + kfree(skb); + return NULL; +} + int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv) { struct ethhdr *ethhdr = (struct ethhdr *)skb->data; @@ -296,7 +323,7 @@ int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv) if (is_multicast_ether_addr(ethhdr->h_dest)) { orig_node = gw_get_selected_orig(bat_priv); if (orig_node) - goto find_router; + goto prepare_packet; }

/* check for tt host - increases orig_node refcount. @@ -304,33 +331,22 @@ int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv) orig_node = transtable_search(bat_priv, ethhdr->h_source, ethhdr->h_dest);

-find_router: +prepare_packet: /** * find_router(): * - if orig_node is NULL it returns NULL * - increases neigh_nodes refcount if found. */ neigh_node = find_router(bat_priv, orig_node, NULL); - if (!neigh_node) goto out;

- if (my_skb_head_push(skb, sizeof(*unicast_packet)) < 0) + skb = prepare_unicast_packet(skb, orig_node); + if (!skb) goto out;

unicast_packet = (struct unicast_packet *)skb->data;

- unicast_packet->version = COMPAT_VERSION; - /* batman packet type: unicast */ - unicast_packet->packet_type = BAT_UNICAST; - /* set unicast ttl */ - unicast_packet->ttl = TTL; - /* copy the destination for faster routing */ - memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN); - /* set the destination tt version number */ - unicast_packet->ttvn = - (uint8_t)atomic_read(&orig_node->last_ttvn); - if (atomic_read(&bat_priv->fragmentation) && data_len + sizeof(*unicast_packet) > neigh_node->if_incoming->net_dev->mtu) { @@ -350,7 +366,7 @@ out: neigh_node_free_ref(neigh_node); if (orig_node) orig_node_free_ref(orig_node); - if (ret == 1) + if (ret == 1 && skb) kfree_skb(skb); return ret; } diff --git a/unicast.h b/unicast.h index 8fd5535..f53a735 100644 --- a/unicast.h +++ b/unicast.h @@ -33,6 +33,8 @@ void frag_list_free(struct list_head *head); int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv); int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv, struct hard_iface *hard_iface, const uint8_t dstaddr[]); +struct sk_buff *prepare_unicast_packet(struct sk_buff *skb, + struct orig_node *orig_node);

static inline int frag_can_reassemble(const struct sk_buff *skb, int mtu) {

Add all the relevant functions in order to manage a Distributed Hash Table over the B.A.T.M.A.N.-adv network. It will later be used to store several ARP entries and implement DAT (Distributed ARP Table)

Signed-off-by: Antonio Quartulli ordex@autistici.org --- Makefile.kbuild | 1 + arp.c | 185 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ arp.h | 46 +++++++++++++ hard-interface.c | 2 + main.h | 7 ++ originator.c | 1 + soft-interface.c | 3 + types.h | 7 ++ 8 files changed, 252 insertions(+), 0 deletions(-) create mode 100644 arp.c create mode 100644 arp.h

diff --git a/Makefile.kbuild b/Makefile.kbuild index bd7e93c..c8d6543 100644 --- a/Makefile.kbuild +++ b/Makefile.kbuild @@ -32,6 +32,7 @@ ccflags-y += -DSOURCE_VERSION="$(REVISION)" endif

obj-m += batman-adv.o +batman-adv-y += arp.o batman-adv-y += bat_debugfs.o batman-adv-y += bat_iv_ogm.o batman-adv-y += bat_sysfs.o diff --git a/arp.c b/arp.c new file mode 100644 index 0000000..39043b8 --- /dev/null +++ b/arp.c @@ -0,0 +1,185 @@ +/* + * Copyright (C) 2011 B.A.T.M.A.N. contributors: + * + * Antonio Quartulli + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA + * + */ + +#include <linux/if_ether.h> +#include <linux/if_arp.h> + +#include "main.h" +#include "arp.h" +#include "hard-interface.h" +#include "originator.h" +#include "send.h" +#include "types.h" +#include "unicast.h" + +/* Given a key, selects the candidates which the DHT message has to be sent to. + * An originator O is selected if and only if its DHT_ID value is one of three + * closest values (but not greater) then the hash value of the key. + * ip_dst is the key. + * + * return an array of size DHT_CANDIDATES_NUM */ +static struct dht_candidate *dht_select_candidates(struct bat_priv *bat_priv, + uint32_t ip_dst) +{ + struct hashtable_t *hash = bat_priv->orig_hash; + struct hlist_node *node; + struct hlist_head *head; + struct orig_node *orig_node, *max_orig_node = NULL; + int select, i, j; + uint16_t last_max = USHRT_MAX, max, tmp_max, ip_key; + struct dht_candidate *res; + bool chosen_me = false; + + if (!hash) + return NULL; + + res = kmalloc(DHT_CANDIDATES_NUM * sizeof(*res), GFP_ATOMIC); + if (!res) + return NULL; + + ip_key = hash_ipv4(&ip_dst, USHRT_MAX); + + bat_dbg(DBG_ARP, bat_priv, "DHT_SEL_CAND key: %pI4 %u\n", &ip_dst, + ip_key); + + for (select = 0; select < DHT_CANDIDATES_NUM; select++) { + max = 0; + max_orig_node = NULL; + if (!chosen_me) { + /* if true, wrap around the key space */ + if (bat_priv->dht_hash > ip_key) + max = USHRT_MAX - bat_priv->dht_hash + + ip_key; + else + max = ip_key - bat_priv->dht_hash; + max = bat_priv->dht_hash; + res[select].type = DHT_CANDIDATE_ME; + } else + res[select].type = DHT_CANDIDATE_NULL; + /* for all origins... */ + for (i = 0; i < hash->size; i++) { + head = &hash->table[i]; + + rcu_read_lock(); + hlist_for_each_entry_rcu(orig_node, node, head, + hash_entry) { + if (orig_node->dht_hash > ip_key) + tmp_max = USHRT_MAX - + orig_node->dht_hash + ip_key; + else + tmp_max = ip_key - orig_node->dht_hash; + + /* this is closest! */ + if (tmp_max <= max) + continue; + + /* this has already been selected */ + if (tmp_max > last_max) + continue; + + if (!atomic_inc_not_zero(&orig_node->refcount)) + continue; + + /* In case of hash collision we can select two + * nodes with the same hash, but we have ensure + * they are different */ + if (tmp_max == last_max) { + for (j = 0; j < select; j++) + if (res[j].orig_node == + orig_node) + break; + if (j < select) + continue; + } + + if (!atomic_inc_not_zero(&orig_node->refcount)) + continue; + + max = tmp_max; + if (max_orig_node) + orig_node_free_ref(max_orig_node); + max_orig_node = orig_node; + } + rcu_read_unlock(); + } + last_max = max; + if (max_orig_node) { + res[select].type = DHT_CANDIDATE_ORIG; + res[select].orig_node = max_orig_node; + bat_dbg(DBG_ARP, bat_priv, "DHT_SEL_CAND %d: %pM %u\n", + select, max_orig_node->orig, max); + } + if (res[select].type == DHT_CANDIDATE_ME) { + chosen_me = true; + bat_dbg(DBG_ARP, bat_priv, "DHT_SEL_CAND %d: ME %u\n", + select, bat_priv->dht_hash); + } + + max_orig_node = NULL; + } + + return res; +} + +/* + * Sends the skb payload passed as argument to the candidates selected for + * 'ip'. The skb is copied by means of pskb_copy() and is sent as unicast packet + * to each of the selected candidate. */ +static bool dht_send_data(struct bat_priv *bat_priv, struct sk_buff *skb, + uint32_t ip) +{ + int i; + bool ret = false; + struct neigh_node *neigh_node = NULL; + struct sk_buff *tmp_skb; + struct dht_candidate *cand = dht_select_candidates(bat_priv, ip); + + if (!cand) + goto out; + + bat_dbg(DBG_ARP, bat_priv, "DHT_SEND for %pI4\n", &ip); + + for (i = 0; i < DHT_CANDIDATES_NUM; i++) { + if (cand[i].type == DHT_CANDIDATE_ME || + cand[i].type == DHT_CANDIDATE_NULL) { + continue; + } + + neigh_node = orig_node_get_router(cand[i].orig_node); + if (!neigh_node) + goto free_orig; + + tmp_skb = pskb_copy(skb, GFP_ATOMIC); + tmp_skb = prepare_unicast_packet(tmp_skb, cand[i].orig_node); + if (tmp_skb) + send_skb_packet(tmp_skb, neigh_node->if_incoming, + neigh_node->addr); + /* set ret to true only if we send at least one request */ + ret = true; + neigh_node_free_ref(neigh_node); +free_orig: + orig_node_free_ref(cand[i].orig_node); + } + +out: + kfree(cand); + return ret; +} diff --git a/arp.h b/arp.h new file mode 100644 index 0000000..ee1a8b3 --- /dev/null +++ b/arp.h @@ -0,0 +1,46 @@ +/* + * Copyright (C) 2011 B.A.T.M.A.N. contributors: + * + * Antonio Quartulli + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA + * + */ + +#ifndef _NET_BATMAN_ADV_ARP_H_ +#define _NET_BATMAN_ADV_ARP_H_ + +/* hash function to choose an entry in a hash table of given size */ +/* hash algorithm from http://en.wikipedia.org/wiki/Hash_table */ +static inline uint32_t hash_ipv4(const void *data, uint32_t size) +{ + const unsigned char *key = data; + uint32_t hash = 0; + size_t i; + + for (i = 0; i < 4; i++) { + hash += key[i]; + hash += (hash << 10); + hash ^= (hash >> 6); + } + + hash += (hash << 3); + hash ^= (hash >> 11); + hash += (hash << 15); + + return hash % size; +} + +#endif /* _NET_BATMAN_ADV_ARP_H_ */ diff --git a/hard-interface.c b/hard-interface.c index 7704df4..3508934 100644 --- a/hard-interface.c +++ b/hard-interface.c @@ -117,6 +117,8 @@ static void primary_if_update_addr(struct bat_priv *bat_priv) if (!primary_if) goto out;

+ bat_priv->dht_hash = choose_orig(bat_priv, USHRT_MAX); + vis_packet = (struct vis_packet *) bat_priv->my_vis_info->skb_packet->data; memcpy(vis_packet->vis_orig, primary_if->net_dev->dev_addr, ETH_ALEN); diff --git a/main.h b/main.h index f3978c0..2ca7b08 100644 --- a/main.h +++ b/main.h @@ -64,6 +64,9 @@

#define NULL_IFINDEX 0 /* dummy ifindex used to avoid iface checks */

+/* numbers of originator to contact for any STORE/GET DHT operation */ +#define DHT_CANDIDATES_NUM 3 + #define NUM_WORDS (TQ_LOCAL_WINDOW_SIZE / WORD_BIT_SIZE)

#define LOG_BUF_LEN 8192 /* has to be a power of 2 */ @@ -106,6 +109,10 @@ enum uev_type {

#define GW_THRESHOLD 50

+#define DHT_CANDIDATE_NULL 0 +#define DHT_CANDIDATE_ME 1 +#define DHT_CANDIDATE_ORIG 2 + /* * Debug Messages */ diff --git a/originator.c b/originator.c index 0bc2045..9673b44 100644 --- a/originator.c +++ b/originator.c @@ -222,6 +222,7 @@ struct orig_node *get_orig_node(struct bat_priv *bat_priv, const uint8_t *addr) orig_node->tt_poss_change = false; orig_node->bat_priv = bat_priv; memcpy(orig_node->orig, addr, ETH_ALEN); + orig_node->dht_hash = choose_orig(addr, USHRT_MAX); orig_node->router = NULL; orig_node->tt_crc = 0; atomic_set(&orig_node->last_ttvn, 0); diff --git a/soft-interface.c b/soft-interface.c index 45297c8..ca15aa7 100644 --- a/soft-interface.c +++ b/soft-interface.c @@ -20,6 +20,7 @@ */

#include "main.h" +#include "arp.h" #include "soft-interface.h" #include "hard-interface.h" #include "routing.h" @@ -855,6 +856,8 @@ struct net_device *softif_create(const char *name) bat_priv->primary_if = NULL; bat_priv->num_ifaces = 0;

+ bat_priv->dht_hash = 0; + ret = sysfs_add_meshif(soft_iface); if (ret < 0) goto unreg_soft_iface; diff --git a/types.h b/types.h index ab8d0fe..837bc42 100644 --- a/types.h +++ b/types.h @@ -67,6 +67,7 @@ struct hard_iface { struct orig_node { uint8_t orig[ETH_ALEN]; uint8_t primary_addr[ETH_ALEN]; + uint16_t dht_hash; struct neigh_node __rcu *router; /* rcu protected pointer */ unsigned long *bcast_own; uint8_t *bcast_own_sum; @@ -204,6 +205,7 @@ struct bat_priv { struct gw_node __rcu *curr_gw; /* rcu protected pointer */ atomic_t gw_reselect; struct hard_iface __rcu *primary_if; /* rcu protected pointer */ + uint16_t dht_hash; struct vis_info *my_vis_info; };

@@ -343,4 +345,9 @@ struct softif_neigh { struct rcu_head rcu; };

+struct dht_candidate { + int type; + struct orig_node *orig_node; +}; + #endif /* _NET_BATMAN_ADV_TYPES_H_ */

ARP messages are now parsed to make it possible to trigger special actions depending on their types (snooping).

Signed-off-by: Antonio Quartulli ordex@autistici.org --- arp.c | 43 +++++++++++++++++++++++++++++++++++++++++++ arp.h | 7 +++++++ 2 files changed, 50 insertions(+), 0 deletions(-)

diff --git a/arp.c b/arp.c index 39043b8..ea7cc1e 100644 --- a/arp.c +++ b/arp.c @@ -183,3 +183,46 @@ out: kfree(cand); return ret; } + +/* Returns arphdr->ar_op if the skb contains a valid ARP packet, otherwise + * returns 0 */ +uint16_t arp_get_type(struct bat_priv *bat_priv, struct sk_buff *skb) +{ + struct arphdr *arphdr; + struct ethhdr *ethhdr; + uint16_t type = 0; + + if (unlikely(!pskb_may_pull(skb, ETH_HLEN))) + goto out; + + ethhdr = (struct ethhdr *)skb_mac_header(skb); + + if (ethhdr->h_proto != htons(ETH_P_ARP)) + goto out; + + if (unlikely(!pskb_may_pull(skb, ETH_HLEN + arp_hdr_len(skb->dev) + 8 + 12))) + goto out; + + arphdr = (struct arphdr *)(skb->data + sizeof(struct ethhdr)); + + /* Check whether the ARP packet carries a valid + * IP information */ + if (arphdr->ar_hrd != htons(ARPHRD_ETHER)) + goto out; + + if (arphdr->ar_pro != htons(ETH_P_IP)) + goto out; + + if (arphdr->ar_hln != ETH_ALEN) + goto out; + + if (arphdr->ar_pln != 4) + goto out; + + type = ntohs(arphdr->ar_op); + bat_dbg(DBG_ARP, bat_priv, "ARP message of type %d recognised " + "[%pM-%pI4 %pM-%pI4]\n", type, ARP_HW_SRC(skb), + &ARP_IP_SRC(skb), ARP_HW_DST(skb), &ARP_IP_DST(skb)); +out: + return type; +} diff --git a/arp.h b/arp.h index ee1a8b3..56b0a0a 100644 --- a/arp.h +++ b/arp.h @@ -22,6 +22,13 @@ #ifndef _NET_BATMAN_ADV_ARP_H_ #define _NET_BATMAN_ADV_ARP_H_

+#define ARP_HW_SRC(skb) ((uint8_t *)(skb->data) + sizeof(struct ethhdr) + sizeof(struct arphdr)) +#define ARP_IP_SRC(skb) (*(uint32_t *)(ARP_HW_SRC(skb) + ETH_ALEN)) +#define ARP_HW_DST(skb) (ARP_HW_SRC(skb) + ETH_ALEN + 4) +#define ARP_IP_DST(skb) (*(uint32_t *)(ARP_HW_SRC(skb) + ETH_ALEN * 2 + 4)) + +uint16_t arp_get_type(struct bat_priv *bat_priv, struct sk_buff *skb); + /* hash function to choose an entry in a hash table of given size */ /* hash algorithm from http://en.wikipedia.org/wiki/Hash_table */ static inline uint32_t hash_ipv4(const void *data, uint32_t size)

The default timeout value for ARP entries belonging to any soft_iface ARP table has been incremented by a factor 4. This is necessary because the DHT will store several network entries in the soft_iface ARP table.

Signed-off-by: Antonio Quartulli ordex@autistici.org --- main.h | 4 ++++ soft-interface.c | 17 +++++++++++++++++ 2 files changed, 21 insertions(+), 0 deletions(-)

diff --git a/main.h b/main.h index 13f63d8..8c534b4 100644 --- a/main.h +++ b/main.h @@ -69,6 +69,10 @@ /* numbers of originator to contact for any STORE/GET DHT operation */ #define DHT_CANDIDATES_NUM 3

+/* Factor which default ARP timeout values of the soft_iface table are + * multiplied by */ +#define ARP_TIMEOUT_FACTOR 4 + #define NUM_WORDS (TQ_LOCAL_WINDOW_SIZE / WORD_BIT_SIZE)

#define LOG_BUF_LEN 8192 /* has to be a power of 2 */ diff --git a/soft-interface.c b/soft-interface.c index db8c6b1..577d0ff 100644 --- a/soft-interface.c +++ b/soft-interface.c @@ -36,6 +36,7 @@ #include <linux/ethtool.h> #include <linux/etherdevice.h> #include <linux/if_vlan.h> +#include <linux/inetdevice.h> #include "unicast.h"

@@ -832,6 +833,7 @@ static void interface_setup(struct net_device *dev) struct net_device *softif_create(const char *name) { struct net_device *soft_iface; + struct in_device *in_dev; struct bat_priv *bat_priv; int ret;

@@ -847,6 +849,21 @@ struct net_device *softif_create(const char *name) goto free_soft_iface; }

+ in_dev = in_dev_get(soft_iface); + if (!in_dev) { + pr_err("Unable to set ARP parameters for the batman interface " + "'%s'\n", name); + goto free_soft_iface; + } + + /* Introduce a delay in the ARP state-machine transactions. Entries + * will be kept in the ARP table for the default time multiplied by 4 */ + in_dev->arp_parms->base_reachable_time *= ARP_TIMEOUT_FACTOR; + in_dev->arp_parms->gc_staletime *= ARP_TIMEOUT_FACTOR; + in_dev->arp_parms->reachable_time *= ARP_TIMEOUT_FACTOR; + + in_dev_put(in_dev); + bat_priv = netdev_priv(soft_iface);

atomic_set(&bat_priv->aggregated_ogms, 1);