351 lines
8.8 KiB
C
351 lines
8.8 KiB
C
/*
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* Copyright (C) 2010-2011 B.A.T.M.A.N. contributors:
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*
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* Andreas Langer
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA
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*
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*/
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#include "main.h"
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#include "unicast.h"
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#include "send.h"
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#include "soft-interface.h"
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#include "gateway_client.h"
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#include "originator.h"
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#include "hash.h"
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#include "translation-table.h"
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#include "routing.h"
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#include "hard-interface.h"
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static struct sk_buff *frag_merge_packet(struct list_head *head,
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struct frag_packet_list_entry *tfp,
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struct sk_buff *skb)
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{
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struct unicast_frag_packet *up =
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(struct unicast_frag_packet *)skb->data;
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struct sk_buff *tmp_skb;
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struct unicast_packet *unicast_packet;
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int hdr_len = sizeof(struct unicast_packet);
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int uni_diff = sizeof(struct unicast_frag_packet) - hdr_len;
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/* set skb to the first part and tmp_skb to the second part */
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if (up->flags & UNI_FRAG_HEAD) {
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tmp_skb = tfp->skb;
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} else {
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tmp_skb = skb;
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skb = tfp->skb;
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}
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if (skb_linearize(skb) < 0 || skb_linearize(tmp_skb) < 0)
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goto err;
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skb_pull(tmp_skb, sizeof(struct unicast_frag_packet));
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if (pskb_expand_head(skb, 0, tmp_skb->len, GFP_ATOMIC) < 0)
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goto err;
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/* move free entry to end */
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tfp->skb = NULL;
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tfp->seqno = 0;
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list_move_tail(&tfp->list, head);
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memcpy(skb_put(skb, tmp_skb->len), tmp_skb->data, tmp_skb->len);
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kfree_skb(tmp_skb);
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memmove(skb->data + uni_diff, skb->data, hdr_len);
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unicast_packet = (struct unicast_packet *) skb_pull(skb, uni_diff);
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unicast_packet->packet_type = BAT_UNICAST;
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return skb;
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err:
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/* free buffered skb, skb will be freed later */
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kfree_skb(tfp->skb);
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return NULL;
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}
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static void frag_create_entry(struct list_head *head, struct sk_buff *skb)
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{
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struct frag_packet_list_entry *tfp;
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struct unicast_frag_packet *up =
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(struct unicast_frag_packet *)skb->data;
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/* free and oldest packets stand at the end */
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tfp = list_entry((head)->prev, typeof(*tfp), list);
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kfree_skb(tfp->skb);
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tfp->seqno = ntohs(up->seqno);
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tfp->skb = skb;
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list_move(&tfp->list, head);
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return;
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}
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static int frag_create_buffer(struct list_head *head)
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{
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int i;
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struct frag_packet_list_entry *tfp;
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for (i = 0; i < FRAG_BUFFER_SIZE; i++) {
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tfp = kmalloc(sizeof(struct frag_packet_list_entry),
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GFP_ATOMIC);
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if (!tfp) {
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frag_list_free(head);
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return -ENOMEM;
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}
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tfp->skb = NULL;
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tfp->seqno = 0;
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INIT_LIST_HEAD(&tfp->list);
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list_add(&tfp->list, head);
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}
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return 0;
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}
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static struct frag_packet_list_entry *frag_search_packet(struct list_head *head,
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struct unicast_frag_packet *up)
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{
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struct frag_packet_list_entry *tfp;
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struct unicast_frag_packet *tmp_up = NULL;
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uint16_t search_seqno;
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if (up->flags & UNI_FRAG_HEAD)
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search_seqno = ntohs(up->seqno)+1;
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else
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search_seqno = ntohs(up->seqno)-1;
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list_for_each_entry(tfp, head, list) {
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if (!tfp->skb)
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continue;
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if (tfp->seqno == ntohs(up->seqno))
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goto mov_tail;
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tmp_up = (struct unicast_frag_packet *)tfp->skb->data;
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if (tfp->seqno == search_seqno) {
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if ((tmp_up->flags & UNI_FRAG_HEAD) !=
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(up->flags & UNI_FRAG_HEAD))
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return tfp;
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else
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goto mov_tail;
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}
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}
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return NULL;
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mov_tail:
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list_move_tail(&tfp->list, head);
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return NULL;
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}
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void frag_list_free(struct list_head *head)
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{
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struct frag_packet_list_entry *pf, *tmp_pf;
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if (!list_empty(head)) {
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list_for_each_entry_safe(pf, tmp_pf, head, list) {
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kfree_skb(pf->skb);
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list_del(&pf->list);
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kfree(pf);
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}
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}
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return;
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}
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/* frag_reassemble_skb():
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* returns NET_RX_DROP if the operation failed - skb is left intact
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* returns NET_RX_SUCCESS if the fragment was buffered (skb_new will be NULL)
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* or the skb could be reassembled (skb_new will point to the new packet and
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* skb was freed)
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*/
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int frag_reassemble_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
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struct sk_buff **new_skb)
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{
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struct orig_node *orig_node;
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struct frag_packet_list_entry *tmp_frag_entry;
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int ret = NET_RX_DROP;
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struct unicast_frag_packet *unicast_packet =
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(struct unicast_frag_packet *)skb->data;
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*new_skb = NULL;
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spin_lock_bh(&bat_priv->orig_hash_lock);
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orig_node = ((struct orig_node *)
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hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
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unicast_packet->orig));
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if (!orig_node) {
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pr_debug("couldn't find originator in orig_hash\n");
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goto out;
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}
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orig_node->last_frag_packet = jiffies;
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if (list_empty(&orig_node->frag_list) &&
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frag_create_buffer(&orig_node->frag_list)) {
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pr_debug("couldn't create frag buffer\n");
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goto out;
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}
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tmp_frag_entry = frag_search_packet(&orig_node->frag_list,
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unicast_packet);
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if (!tmp_frag_entry) {
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frag_create_entry(&orig_node->frag_list, skb);
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ret = NET_RX_SUCCESS;
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goto out;
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}
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*new_skb = frag_merge_packet(&orig_node->frag_list, tmp_frag_entry,
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skb);
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/* if not, merge failed */
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if (*new_skb)
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ret = NET_RX_SUCCESS;
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out:
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spin_unlock_bh(&bat_priv->orig_hash_lock);
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return ret;
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}
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int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
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struct batman_if *batman_if, uint8_t dstaddr[])
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{
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struct unicast_packet tmp_uc, *unicast_packet;
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struct sk_buff *frag_skb;
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struct unicast_frag_packet *frag1, *frag2;
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int uc_hdr_len = sizeof(struct unicast_packet);
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int ucf_hdr_len = sizeof(struct unicast_frag_packet);
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int data_len = skb->len - uc_hdr_len;
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int large_tail = 0;
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uint16_t seqno;
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if (!bat_priv->primary_if)
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goto dropped;
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frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len);
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if (!frag_skb)
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goto dropped;
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skb_reserve(frag_skb, ucf_hdr_len);
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unicast_packet = (struct unicast_packet *) skb->data;
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memcpy(&tmp_uc, unicast_packet, uc_hdr_len);
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skb_split(skb, frag_skb, data_len / 2 + uc_hdr_len);
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if (my_skb_head_push(skb, ucf_hdr_len - uc_hdr_len) < 0 ||
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my_skb_head_push(frag_skb, ucf_hdr_len) < 0)
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goto drop_frag;
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frag1 = (struct unicast_frag_packet *)skb->data;
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frag2 = (struct unicast_frag_packet *)frag_skb->data;
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memcpy(frag1, &tmp_uc, sizeof(struct unicast_packet));
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frag1->ttl--;
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frag1->version = COMPAT_VERSION;
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frag1->packet_type = BAT_UNICAST_FRAG;
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memcpy(frag1->orig, bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
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memcpy(frag2, frag1, sizeof(struct unicast_frag_packet));
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if (data_len & 1)
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large_tail = UNI_FRAG_LARGETAIL;
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frag1->flags = UNI_FRAG_HEAD | large_tail;
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frag2->flags = large_tail;
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seqno = atomic_add_return(2, &batman_if->frag_seqno);
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frag1->seqno = htons(seqno - 1);
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frag2->seqno = htons(seqno);
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send_skb_packet(skb, batman_if, dstaddr);
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send_skb_packet(frag_skb, batman_if, dstaddr);
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return NET_RX_SUCCESS;
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drop_frag:
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kfree_skb(frag_skb);
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dropped:
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kfree_skb(skb);
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return NET_RX_DROP;
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}
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int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv)
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{
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struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
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struct unicast_packet *unicast_packet;
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struct orig_node *orig_node = NULL;
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struct batman_if *batman_if;
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struct neigh_node *router;
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int data_len = skb->len;
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uint8_t dstaddr[6];
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spin_lock_bh(&bat_priv->orig_hash_lock);
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/* get routing information */
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if (is_multicast_ether_addr(ethhdr->h_dest))
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orig_node = (struct orig_node *)gw_get_selected(bat_priv);
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/* check for hna host */
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if (!orig_node)
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orig_node = transtable_search(bat_priv, ethhdr->h_dest);
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router = find_router(bat_priv, orig_node, NULL);
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if (!router)
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goto unlock;
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/* don't lock while sending the packets ... we therefore
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* copy the required data before sending */
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batman_if = router->if_incoming;
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memcpy(dstaddr, router->addr, ETH_ALEN);
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spin_unlock_bh(&bat_priv->orig_hash_lock);
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if (batman_if->if_status != IF_ACTIVE)
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goto dropped;
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if (my_skb_head_push(skb, sizeof(struct unicast_packet)) < 0)
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goto dropped;
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unicast_packet = (struct unicast_packet *)skb->data;
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unicast_packet->version = COMPAT_VERSION;
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/* batman packet type: unicast */
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unicast_packet->packet_type = BAT_UNICAST;
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/* set unicast ttl */
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unicast_packet->ttl = TTL;
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/* copy the destination for faster routing */
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memcpy(unicast_packet->dest, orig_node->orig, ETH_ALEN);
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if (atomic_read(&bat_priv->fragmentation) &&
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data_len + sizeof(struct unicast_packet) >
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batman_if->net_dev->mtu) {
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/* send frag skb decreases ttl */
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unicast_packet->ttl++;
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return frag_send_skb(skb, bat_priv, batman_if,
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dstaddr);
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}
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send_skb_packet(skb, batman_if, dstaddr);
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return 0;
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unlock:
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spin_unlock_bh(&bat_priv->orig_hash_lock);
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dropped:
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kfree_skb(skb);
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return 1;
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}
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