linux/net/batman-adv/unicast.c

481 lines
13 KiB
C

/* Copyright (C) 2010-2012 B.A.T.M.A.N. contributors:
*
* Andreas Langer
*
* 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 "main.h"
#include "unicast.h"
#include "send.h"
#include "soft-interface.h"
#include "gateway_client.h"
#include "originator.h"
#include "hash.h"
#include "translation-table.h"
#include "routing.h"
#include "hard-interface.h"
static struct sk_buff *
batadv_frag_merge_packet(struct list_head *head,
struct batadv_frag_packet_list_entry *tfp,
struct sk_buff *skb)
{
struct batadv_unicast_frag_packet *up;
struct sk_buff *tmp_skb;
struct batadv_unicast_packet *unicast_packet;
int hdr_len = sizeof(*unicast_packet);
int uni_diff = sizeof(*up) - hdr_len;
uint8_t *packet_pos;
up = (struct batadv_unicast_frag_packet *)skb->data;
/* set skb to the first part and tmp_skb to the second part */
if (up->flags & BATADV_UNI_FRAG_HEAD) {
tmp_skb = tfp->skb;
} else {
tmp_skb = skb;
skb = tfp->skb;
}
if (skb_linearize(skb) < 0 || skb_linearize(tmp_skb) < 0)
goto err;
skb_pull(tmp_skb, sizeof(*up));
if (pskb_expand_head(skb, 0, tmp_skb->len, GFP_ATOMIC) < 0)
goto err;
/* move free entry to end */
tfp->skb = NULL;
tfp->seqno = 0;
list_move_tail(&tfp->list, head);
memcpy(skb_put(skb, tmp_skb->len), tmp_skb->data, tmp_skb->len);
kfree_skb(tmp_skb);
memmove(skb->data + uni_diff, skb->data, hdr_len);
packet_pos = skb_pull(skb, uni_diff);
unicast_packet = (struct batadv_unicast_packet *)packet_pos;
unicast_packet->header.packet_type = BATADV_UNICAST;
return skb;
err:
/* free buffered skb, skb will be freed later */
kfree_skb(tfp->skb);
return NULL;
}
static void batadv_frag_create_entry(struct list_head *head,
struct sk_buff *skb)
{
struct batadv_frag_packet_list_entry *tfp;
struct batadv_unicast_frag_packet *up;
up = (struct batadv_unicast_frag_packet *)skb->data;
/* free and oldest packets stand at the end */
tfp = list_entry((head)->prev, typeof(*tfp), list);
kfree_skb(tfp->skb);
tfp->seqno = ntohs(up->seqno);
tfp->skb = skb;
list_move(&tfp->list, head);
return;
}
static int batadv_frag_create_buffer(struct list_head *head)
{
int i;
struct batadv_frag_packet_list_entry *tfp;
for (i = 0; i < BATADV_FRAG_BUFFER_SIZE; i++) {
tfp = kmalloc(sizeof(*tfp), GFP_ATOMIC);
if (!tfp) {
batadv_frag_list_free(head);
return -ENOMEM;
}
tfp->skb = NULL;
tfp->seqno = 0;
INIT_LIST_HEAD(&tfp->list);
list_add(&tfp->list, head);
}
return 0;
}
static struct batadv_frag_packet_list_entry *
batadv_frag_search_packet(struct list_head *head,
const struct batadv_unicast_frag_packet *up)
{
struct batadv_frag_packet_list_entry *tfp;
struct batadv_unicast_frag_packet *tmp_up = NULL;
int is_head_tmp, is_head;
uint16_t search_seqno;
if (up->flags & BATADV_UNI_FRAG_HEAD)
search_seqno = ntohs(up->seqno)+1;
else
search_seqno = ntohs(up->seqno)-1;
is_head = !!(up->flags & BATADV_UNI_FRAG_HEAD);
list_for_each_entry(tfp, head, list) {
if (!tfp->skb)
continue;
if (tfp->seqno == ntohs(up->seqno))
goto mov_tail;
tmp_up = (struct batadv_unicast_frag_packet *)tfp->skb->data;
if (tfp->seqno == search_seqno) {
is_head_tmp = !!(tmp_up->flags & BATADV_UNI_FRAG_HEAD);
if (is_head_tmp != is_head)
return tfp;
else
goto mov_tail;
}
}
return NULL;
mov_tail:
list_move_tail(&tfp->list, head);
return NULL;
}
void batadv_frag_list_free(struct list_head *head)
{
struct batadv_frag_packet_list_entry *pf, *tmp_pf;
if (!list_empty(head)) {
list_for_each_entry_safe(pf, tmp_pf, head, list) {
kfree_skb(pf->skb);
list_del(&pf->list);
kfree(pf);
}
}
return;
}
/* frag_reassemble_skb():
* returns NET_RX_DROP if the operation failed - skb is left intact
* returns NET_RX_SUCCESS if the fragment was buffered (skb_new will be NULL)
* or the skb could be reassembled (skb_new will point to the new packet and
* skb was freed)
*/
int batadv_frag_reassemble_skb(struct sk_buff *skb,
struct batadv_priv *bat_priv,
struct sk_buff **new_skb)
{
struct batadv_orig_node *orig_node;
struct batadv_frag_packet_list_entry *tmp_frag_entry;
int ret = NET_RX_DROP;
struct batadv_unicast_frag_packet *unicast_packet;
unicast_packet = (struct batadv_unicast_frag_packet *)skb->data;
*new_skb = NULL;
orig_node = batadv_orig_hash_find(bat_priv, unicast_packet->orig);
if (!orig_node)
goto out;
orig_node->last_frag_packet = jiffies;
if (list_empty(&orig_node->frag_list) &&
batadv_frag_create_buffer(&orig_node->frag_list)) {
pr_debug("couldn't create frag buffer\n");
goto out;
}
tmp_frag_entry = batadv_frag_search_packet(&orig_node->frag_list,
unicast_packet);
if (!tmp_frag_entry) {
batadv_frag_create_entry(&orig_node->frag_list, skb);
ret = NET_RX_SUCCESS;
goto out;
}
*new_skb = batadv_frag_merge_packet(&orig_node->frag_list,
tmp_frag_entry, skb);
/* if not, merge failed */
if (*new_skb)
ret = NET_RX_SUCCESS;
out:
if (orig_node)
batadv_orig_node_free_ref(orig_node);
return ret;
}
int batadv_frag_send_skb(struct sk_buff *skb, struct batadv_priv *bat_priv,
struct batadv_hard_iface *hard_iface,
const uint8_t dstaddr[])
{
struct batadv_unicast_packet tmp_uc, *unicast_packet;
struct batadv_hard_iface *primary_if;
struct sk_buff *frag_skb;
struct batadv_unicast_frag_packet *frag1, *frag2;
int uc_hdr_len = sizeof(*unicast_packet);
int ucf_hdr_len = sizeof(*frag1);
int data_len = skb->len - uc_hdr_len;
int large_tail = 0, ret = NET_RX_DROP;
uint16_t seqno;
primary_if = batadv_primary_if_get_selected(bat_priv);
if (!primary_if)
goto dropped;
frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len);
if (!frag_skb)
goto dropped;
skb_reserve(frag_skb, ucf_hdr_len);
unicast_packet = (struct batadv_unicast_packet *)skb->data;
memcpy(&tmp_uc, unicast_packet, uc_hdr_len);
skb_split(skb, frag_skb, data_len / 2 + uc_hdr_len);
if (batadv_skb_head_push(skb, ucf_hdr_len - uc_hdr_len) < 0 ||
batadv_skb_head_push(frag_skb, ucf_hdr_len) < 0)
goto drop_frag;
frag1 = (struct batadv_unicast_frag_packet *)skb->data;
frag2 = (struct batadv_unicast_frag_packet *)frag_skb->data;
memcpy(frag1, &tmp_uc, sizeof(tmp_uc));
frag1->header.ttl--;
frag1->header.version = BATADV_COMPAT_VERSION;
frag1->header.packet_type = BATADV_UNICAST_FRAG;
memcpy(frag1->orig, primary_if->net_dev->dev_addr, ETH_ALEN);
memcpy(frag2, frag1, sizeof(*frag2));
if (data_len & 1)
large_tail = BATADV_UNI_FRAG_LARGETAIL;
frag1->flags = BATADV_UNI_FRAG_HEAD | large_tail;
frag2->flags = large_tail;
seqno = atomic_add_return(2, &hard_iface->frag_seqno);
frag1->seqno = htons(seqno - 1);
frag2->seqno = htons(seqno);
batadv_send_skb_packet(skb, hard_iface, dstaddr);
batadv_send_skb_packet(frag_skb, hard_iface, dstaddr);
ret = NET_RX_SUCCESS;
goto out;
drop_frag:
kfree_skb(frag_skb);
dropped:
kfree_skb(skb);
out:
if (primary_if)
batadv_hardif_free_ref(primary_if);
return ret;
}
/**
* batadv_unicast_push_and_fill_skb - extends the buffer and initializes the
* common fields for unicast packets
* @skb: packet
* @hdr_size: amount of bytes to push at the beginning of the skb
* @orig_node: the destination node
*
* Returns false if the buffer extension was not possible or true otherwise
*/
static bool batadv_unicast_push_and_fill_skb(struct sk_buff *skb, int hdr_size,
struct batadv_orig_node *orig_node)
{
struct batadv_unicast_packet *unicast_packet;
uint8_t ttvn = (uint8_t)atomic_read(&orig_node->last_ttvn);
if (batadv_skb_head_push(skb, hdr_size) < 0)
return false;
unicast_packet = (struct batadv_unicast_packet *)skb->data;
unicast_packet->header.version = BATADV_COMPAT_VERSION;
/* batman packet type: unicast */
unicast_packet->header.packet_type = BATADV_UNICAST;
/* set unicast ttl */
unicast_packet->header.ttl = BATADV_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 = ttvn;
return true;
}
/**
* batadv_unicast_prepare_skb - encapsulate an skb with a unicast header
* @skb: the skb containing the payload to encapsulate
* @orig_node: the destination node
*
* Returns false if the payload could not be encapsulated or true otherwise
*/
static bool batadv_unicast_prepare_skb(struct sk_buff *skb,
struct batadv_orig_node *orig_node)
{
size_t uni_size = sizeof(struct batadv_unicast_packet);
return batadv_unicast_push_and_fill_skb(skb, uni_size, orig_node);
}
/**
* batadv_unicast_4addr_prepare_skb - encapsulate an skb with a unicast4addr
* header
* @bat_priv: the bat priv with all the soft interface information
* @skb: the skb containing the payload to encapsulate
* @orig_node: the destination node
* @packet_subtype: the batman 4addr packet subtype to use
*
* Returns false if the payload could not be encapsulated or true otherwise
*/
bool batadv_unicast_4addr_prepare_skb(struct batadv_priv *bat_priv,
struct sk_buff *skb,
struct batadv_orig_node *orig,
int packet_subtype)
{
struct batadv_hard_iface *primary_if;
struct batadv_unicast_4addr_packet *unicast_4addr_packet;
bool ret = false;
primary_if = batadv_primary_if_get_selected(bat_priv);
if (!primary_if)
goto out;
/* pull the header space and fill the unicast_packet substructure.
* We can do that because the first member of the unicast_4addr_packet
* is of type struct unicast_packet
*/
if (!batadv_unicast_push_and_fill_skb(skb,
sizeof(*unicast_4addr_packet),
orig))
goto out;
unicast_4addr_packet = (struct batadv_unicast_4addr_packet *)skb->data;
unicast_4addr_packet->u.header.packet_type = BATADV_UNICAST_4ADDR;
memcpy(unicast_4addr_packet->src, primary_if->net_dev->dev_addr,
ETH_ALEN);
unicast_4addr_packet->subtype = packet_subtype;
unicast_4addr_packet->reserved = 0;
ret = true;
out:
if (primary_if)
batadv_hardif_free_ref(primary_if);
return ret;
}
/**
* batadv_unicast_generic_send_skb - send an skb as unicast
* @bat_priv: the bat priv with all the soft interface information
* @skb: payload to send
* @packet_type: the batman unicast packet type to use
* @packet_subtype: the batman packet subtype. It is ignored if packet_type is
* not BATADV_UNICAT_4ADDR
*
* Returns 1 in case of error or 0 otherwise
*/
int batadv_unicast_generic_send_skb(struct batadv_priv *bat_priv,
struct sk_buff *skb, int packet_type,
int packet_subtype)
{
struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
struct batadv_unicast_packet *unicast_packet;
struct batadv_orig_node *orig_node;
struct batadv_neigh_node *neigh_node;
int data_len = skb->len;
int ret = NET_RX_DROP;
unsigned int dev_mtu;
/* get routing information */
if (is_multicast_ether_addr(ethhdr->h_dest)) {
orig_node = batadv_gw_get_selected_orig(bat_priv);
if (orig_node)
goto find_router;
}
/* check for tt host - increases orig_node refcount.
* returns NULL in case of AP isolation
*/
orig_node = batadv_transtable_search(bat_priv, ethhdr->h_source,
ethhdr->h_dest);
find_router:
/* find_router():
* - if orig_node is NULL it returns NULL
* - increases neigh_nodes refcount if found.
*/
neigh_node = batadv_find_router(bat_priv, orig_node, NULL);
if (!neigh_node)
goto out;
switch (packet_type) {
case BATADV_UNICAST:
batadv_unicast_prepare_skb(skb, orig_node);
break;
case BATADV_UNICAST_4ADDR:
batadv_unicast_4addr_prepare_skb(bat_priv, skb, orig_node,
packet_subtype);
break;
default:
/* this function supports UNICAST and UNICAST_4ADDR only. It
* should never be invoked with any other packet type
*/
goto out;
}
unicast_packet = (struct batadv_unicast_packet *)skb->data;
/* inform the destination node that we are still missing a correct route
* for this client. The destination will receive this packet and will
* try to reroute it because the ttvn contained in the header is less
* than the current one
*/
if (batadv_tt_global_client_is_roaming(bat_priv, ethhdr->h_dest))
unicast_packet->ttvn = unicast_packet->ttvn - 1;
dev_mtu = neigh_node->if_incoming->net_dev->mtu;
/* fragmentation mechanism only works for UNICAST (now) */
if (packet_type == BATADV_UNICAST &&
atomic_read(&bat_priv->fragmentation) &&
data_len + sizeof(*unicast_packet) > dev_mtu) {
/* send frag skb decreases ttl */
unicast_packet->header.ttl++;
ret = batadv_frag_send_skb(skb, bat_priv,
neigh_node->if_incoming,
neigh_node->addr);
goto out;
}
if (batadv_send_skb_to_orig(skb, orig_node, NULL))
ret = 0;
out:
if (neigh_node)
batadv_neigh_node_free_ref(neigh_node);
if (orig_node)
batadv_orig_node_free_ref(orig_node);
if (ret == NET_RX_DROP)
kfree_skb(skb);
return ret;
}