[B.A.T.M.A.N.] [PATCH 07/12] batman-adv: Use packet lists for unicast packet sending

Instead of branching the code paths and having several possible methods doing the final preparation and sending of an skb, depending on whether a packet needs to be fragmented or not, this commit now decouples the sending procedure from the fragmentation methods: The fragmentation methods are only manipulating a packet_list and packet_list_entries now so that the fragmentation process becomes transparent for route_unicast_packet().

This further allows easier integration of future extensions that send copies of multiple (modified) unicast packets to several next hop neighbours.

Signed-off-by: Linus Lüssing linus.luessing@ascom.ch --- routing.c | 76 +++++++++++++++----------------------- routing.h | 4 +-- send.c | 14 +++++++ send.h | 7 ++++ soft-interface.c | 3 +- unicast.c | 107 +++++++++++++++++++++++++++++++++++++++++++++++++----- unicast.h | 25 +------------ 7 files changed, 153 insertions(+), 83 deletions(-)

diff --git a/routing.c b/routing.c index 60579fc..ba4756c 100644 --- a/routing.c +++ b/routing.c @@ -1021,21 +1021,24 @@ out: /* find a suitable router for this originator, and use * bonding if possible. increases the found neighbors * refcount.*/ -struct neigh_node *find_router(struct orig_node *orig_node, - struct hard_iface *recv_if) +static void find_router(struct orig_node *orig_node, + struct hard_iface *recv_if, + struct sk_buff *skb, + struct hlist_head *packet_list) { struct bat_priv *bat_priv; struct orig_node *primary_orig_node; struct orig_node *router_orig; struct neigh_node *router, *first_candidate, *tmp_neigh_node; + struct packet_list_entry *entry; static uint8_t zero_mac[ETH_ALEN] = {0, 0, 0, 0, 0, 0}; int bonding_enabled;

if (!orig_node) - return NULL; + return;

if (!orig_node->router) - return NULL; + return;

bat_priv = orig_node->bat_priv;

@@ -1049,7 +1052,7 @@ struct neigh_node *find_router(struct orig_node *orig_node, router_orig = orig_node->router->orig_node; if (!router_orig || !atomic_inc_not_zero(&router->refcount)) { rcu_read_unlock(); - return NULL; + return; }

if ((!recv_if) && (!bonding_enabled)) @@ -1111,7 +1114,7 @@ struct neigh_node *find_router(struct orig_node *orig_node,

if (!router) { rcu_read_unlock(); - return NULL; + return; }

/* selected should point to the next element @@ -1163,7 +1166,16 @@ struct neigh_node *find_router(struct orig_node *orig_node, } return_router: rcu_read_unlock(); - return router; + + entry = kmalloc(sizeof(struct packet_list_entry), GFP_ATOMIC); + if (!entry) { + kfree_skb(skb); + return; + } + + entry->skb = skb; + entry->neigh_node = router; + hlist_add_head(&entry->list, packet_list); }

static int check_unicast_packet(struct sk_buff *skb, int hdr_size) @@ -1192,55 +1204,29 @@ static int check_unicast_packet(struct sk_buff *skb, int hdr_size) }

int route_unicast_packet(struct sk_buff *skb, struct hard_iface *recv_if, - struct orig_node *orig_node, uint8_t packet_type) + struct orig_node *orig_node) { - struct neigh_node *neigh_node = NULL; int ret = NET_RX_DROP; - struct sk_buff *new_skb; + struct hlist_head packet_list;

- /* find_router() increases neigh_nodes refcount if found. */ - neigh_node = find_router(orig_node, recv_if); - - if (!neigh_node) - goto out; + INIT_HLIST_HEAD(&packet_list);

/* create a copy of the skb, if needed, to modify it. */ if (skb_cow(skb, sizeof(struct ethhdr)) < 0) goto out;

- if (packet_type == BAT_UNICAST && - atomic_read(&orig_node->bat_priv->fragmentation) && - skb->len > neigh_node->if_incoming->net_dev->mtu) { - ret = frag_send_skb(skb, orig_node->bat_priv, - neigh_node->if_incoming, neigh_node->addr); - goto out; - } - - if (packet_type == BAT_UNICAST_FRAG && - frag_can_reassemble(skb, neigh_node->if_incoming->net_dev->mtu)) { - - ret = frag_reassemble_skb(skb, orig_node->bat_priv, &new_skb); - - if (ret == NET_RX_DROP) - goto out; - - /* packet was buffered for late merge */ - if (!new_skb) { - ret = NET_RX_SUCCESS; - goto out; - } + /* creates the (initial) packet list */ + find_router(orig_node, recv_if, skb, &packet_list);

- skb = new_skb; - } + /* split packets that won't fit or maybe buffer fragments */ + frag_packet_list(orig_node->bat_priv, &packet_list);

- /* route it */ - send_skb_packet(skb, neigh_node->if_incoming, neigh_node->addr); + /* route them */ + send_packet_list(&packet_list); ret = NET_RX_SUCCESS; goto out;

out: - if (neigh_node) - neigh_node_free_ref(neigh_node); if (orig_node) orig_node_free_ref(orig_node); return ret; @@ -1265,8 +1251,7 @@ int recv_unicast_packet(struct sk_buff *skb, struct hard_iface *recv_if) }

orig_node = orig_hash_find(bat_priv, unicast_packet->dest); - return route_unicast_packet(skb, recv_if, orig_node, - unicast_packet->header.packet_type); + return route_unicast_packet(skb, recv_if, orig_node); }

int recv_ucast_frag_packet(struct sk_buff *skb, struct hard_iface *recv_if) @@ -1301,8 +1286,7 @@ int recv_ucast_frag_packet(struct sk_buff *skb, struct hard_iface *recv_if) }

orig_node = orig_hash_find(bat_priv, unicast_packet->dest); - return route_unicast_packet(skb, recv_if, orig_node, - unicast_packet->header.packet_type); + return route_unicast_packet(skb, recv_if, orig_node); }

diff --git a/routing.h b/routing.h index d97f720..681512b 100644 --- a/routing.h +++ b/routing.h @@ -31,15 +31,13 @@ void update_routes(struct bat_priv *bat_priv, struct orig_node *orig_node, struct neigh_node *neigh_node, unsigned char *hna_buff, int hna_buff_len); int route_unicast_packet(struct sk_buff *skb, struct hard_iface *recv_if, - struct orig_node *orig_node, uint8_t packet_type); + struct orig_node *orig_node); int recv_icmp_packet(struct sk_buff *skb, struct hard_iface *recv_if); int recv_unicast_packet(struct sk_buff *skb, struct hard_iface *recv_if); int recv_ucast_frag_packet(struct sk_buff *skb, struct hard_iface *recv_if); int recv_bcast_packet(struct sk_buff *skb, struct hard_iface *recv_if); int recv_vis_packet(struct sk_buff *skb, struct hard_iface *recv_if); int recv_bat_packet(struct sk_buff *skb, struct hard_iface *recv_if); -struct neigh_node *find_router(struct orig_node *orig_node, - struct hard_iface *recv_if); void bonding_candidate_del(struct orig_node *orig_node, struct neigh_node *neigh_node);

diff --git a/send.c b/send.c index 1f1afce..862ce79 100644 --- a/send.c +++ b/send.c @@ -202,6 +202,20 @@ send_skb_err: return NET_XMIT_DROP; }

+void send_packet_list(struct hlist_head *packet_list) +{ + struct packet_list_entry *entry; + struct hlist_node *pos, *tmp; + + hlist_for_each_entry_safe(entry, pos, tmp, packet_list, list) { + send_skb_packet(entry->skb, entry->neigh_node->if_incoming, + entry->neigh_node->addr); + neigh_node_free_ref(entry->neigh_node); + hlist_del(&entry->list); + kfree(entry); + } +} + /* Send a packet to a given interface */ static void send_packet_to_if(struct forw_packet *forw_packet, struct hard_iface *hard_iface) diff --git a/send.h b/send.h index 7b2ff19..290195e 100644 --- a/send.h +++ b/send.h @@ -22,9 +22,16 @@ #ifndef _NET_BATMAN_ADV_SEND_H_ #define _NET_BATMAN_ADV_SEND_H_

+struct packet_list_entry { + struct hlist_node list; + struct sk_buff *skb; + struct neigh_node *neigh_node; +}; + int send_skb_packet(struct sk_buff *skb, struct hard_iface *hard_iface, uint8_t *dst_addr); +void send_packet_list(struct hlist_head *packet_list); void schedule_own_packet(struct hard_iface *hard_iface); void schedule_forward_packet(struct orig_node *orig_node, struct ethhdr *ethhdr, diff --git a/soft-interface.c b/soft-interface.c index 07fe7c8..8224fdc 100644 --- a/soft-interface.c +++ b/soft-interface.c @@ -466,8 +466,7 @@ void interface_rx(struct net_device *soft_iface, bat_priv->softif_neigh->addr, ETH_ALEN);

orig_node = orig_hash_find(bat_priv, unicast_packet->dest); - ret = route_unicast_packet(skb, recv_if, orig_node, - unicast_packet->header.packet_type); + ret = route_unicast_packet(skb, recv_if, orig_node); if (ret == NET_RX_DROP) goto dropped;

diff --git a/unicast.c b/unicast.c index 54e956b..07ef785 100644 --- a/unicast.c +++ b/unicast.c @@ -217,17 +217,43 @@ out: return ret; }

-int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv, - struct hard_iface *hard_iface, uint8_t dstaddr[]) +static void frag_reassemble_packet(struct packet_list_entry *entry, + struct bat_priv *bat_priv) +{ + struct sk_buff *new_skb = NULL; + int ret; + + ret = frag_reassemble_skb(entry->skb, bat_priv, &new_skb); + + /* Could reassemble packet, leave this new one in list */ + if (new_skb) { + entry->skb = new_skb; + return; + } + + /* merge failed */ + if (ret == NET_RX_DROP) + kfree_skb(entry->skb); + + /* merge failed or skb is buffered, remove from send list */ + neigh_node_free_ref(entry->neigh_node); + hlist_del(&entry->list); + kfree(entry); +} + +static void frag_skb(struct packet_list_entry *entry, struct bat_priv *bat_priv) { struct unicast_packet tmp_uc, *unicast_packet; struct sk_buff *frag_skb; struct unicast_frag_packet *frag1, *frag2; + struct packet_list_entry *frag_entry; int uc_hdr_len = sizeof(struct unicast_packet); int ucf_hdr_len = sizeof(struct unicast_frag_packet); - int data_len = skb->len - uc_hdr_len; + int data_len = entry->skb->len - uc_hdr_len; int large_tail = 0; uint16_t seqno; + struct sk_buff *skb = entry->skb; + struct hard_iface *hard_iface = entry->neigh_node->if_incoming;

if (!bat_priv->primary_if) goto dropped; @@ -266,15 +292,79 @@ int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv, frag1->seqno = htons(seqno - 1); frag2->seqno = htons(seqno);

- send_skb_packet(skb, hard_iface, dstaddr); - send_skb_packet(frag_skb, hard_iface, dstaddr); - return NET_RX_SUCCESS; + frag_entry = kmalloc(sizeof(struct packet_list_entry), GFP_ATOMIC); + if (!frag_entry) + goto drop_frag; + + if (!atomic_inc_not_zero(&entry->neigh_node->refcount)) + goto drop_frag; + + frag_entry->skb = frag_skb; + frag_entry->neigh_node = entry->neigh_node; + hlist_add_before(&frag_entry->list, &entry->list);

drop_frag: kfree_skb(frag_skb); dropped: kfree_skb(skb); - return NET_RX_DROP; + neigh_node_free_ref(entry->neigh_node); + hlist_del(&entry->list); + kfree(entry); +} + +static inline int frag_can_reassemble(struct sk_buff *skb, int mtu) +{ + struct unicast_frag_packet *unicast_packet; + int uneven_correction = 0; + unsigned int merged_size; + + unicast_packet = (struct unicast_frag_packet *)skb->data; + + if (unicast_packet->flags & UNI_FRAG_LARGETAIL) { + if (unicast_packet->flags & UNI_FRAG_HEAD) + uneven_correction = 1; + else + uneven_correction = -1; + } + + merged_size = (skb->len - 2 * sizeof(struct unicast_frag_packet)); + merged_size += sizeof(struct unicast_packet) + uneven_correction; + + return merged_size <= mtu; +} + +void frag_packet_list(struct bat_priv *bat_priv, + struct hlist_head *packet_list) +{ + struct packet_list_entry *entry; + struct hlist_node *pos, *tmp; + uint8_t packet_type; + + hlist_for_each_entry_safe(entry, pos, tmp, packet_list, list) { + packet_type = ((struct batman_header *) + entry->skb->data)->packet_type; + + switch (packet_type) { + case BAT_UNICAST: + if (!atomic_read(&bat_priv->fragmentation) || + entry->skb->len <= + entry->neigh_node->if_incoming->net_dev->mtu) + break; + + frag_skb(entry, bat_priv); + break; + case BAT_UNICAST_FRAG: + if (!frag_can_reassemble(entry->skb, + entry->neigh_node->if_incoming->net_dev->mtu)) + break; + + frag_reassemble_packet(entry, bat_priv); + break; + default: + /* We should never be here... */ + break; + } + } }

int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv) @@ -308,8 +398,7 @@ route: /* copy the destination for faster routing */ memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN);

- ret = route_unicast_packet(skb, NULL, orig_node, - unicast_packet->header.packet_type); + ret = route_unicast_packet(skb, NULL, orig_node);

out: if (ret == NET_RX_DROP) diff --git a/unicast.h b/unicast.h index 16ad7a9..1b4dbb0 100644 --- a/unicast.h +++ b/unicast.h @@ -30,29 +30,8 @@ int frag_reassemble_skb(struct sk_buff *skb, struct bat_priv *bat_priv, struct sk_buff **new_skb); void frag_list_free(struct list_head *head); +void frag_packet_list(struct bat_priv *bat_priv, + struct hlist_head *packet_list); 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, uint8_t dstaddr[]); - -static inline int frag_can_reassemble(struct sk_buff *skb, int mtu) -{ - struct unicast_frag_packet *unicast_packet; - int uneven_correction = 0; - unsigned int merged_size; - - unicast_packet = (struct unicast_frag_packet *)skb->data; - - if (unicast_packet->flags & UNI_FRAG_LARGETAIL) { - if (unicast_packet->flags & UNI_FRAG_HEAD) - uneven_correction = 1; - else - uneven_correction = -1; - } - - merged_size = (skb->len - sizeof(struct unicast_frag_packet)) * 2; - merged_size += sizeof(struct unicast_packet) + uneven_correction; - - return merged_size <= mtu; -}

#endif /* _NET_BATMAN_ADV_UNICAST_H_ */