net: Add batman-adv meshing protocol

B.A.T.M.A.N. (better approach to mobile ad-hoc networking) is a routing
protocol for multi-hop ad-hoc mesh networks. The networks may be wired or
wireless. See http://www.open-mesh.org/ for more information and user space
tools.

Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 343 insertions, 0 deletions

diff --git a/net/batman-adv/unicast.c b/net/batman-adv/unicast.c
new file mode 100644
index 000000000000..dc2e28bed844
--- /dev/null
+++ b/net/batman-adv/unicast.c
@@ -0,0 +1,343 @@
+/*
+ * Copyright (C) 2010 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 *frag_merge_packet(struct list_head *head,
+					 struct frag_packet_list_entry *tfp,
+					 struct sk_buff *skb)
+{
+	struct unicast_frag_packet *up =
+		(struct unicast_frag_packet *)skb->data;
+	struct sk_buff *tmp_skb;
+	struct unicast_packet *unicast_packet;
+	int hdr_len = sizeof(struct unicast_packet),
+	    uni_diff = sizeof(struct unicast_frag_packet) - hdr_len;
+
+	/* set skb to the first part and tmp_skb to the second part */
+	if (up->flags & UNI_FRAG_HEAD) {
+		tmp_skb = tfp->skb;
+	} else {
+		tmp_skb = skb;
+		skb = tfp->skb;
+	}
+
+	skb_pull(tmp_skb, sizeof(struct unicast_frag_packet));
+	if (pskb_expand_head(skb, 0, tmp_skb->len, GFP_ATOMIC) < 0) {
+		/* free buffered skb, skb will be freed later */
+		kfree_skb(tfp->skb);
+		return NULL;
+	}
+
+	/* 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);
+	unicast_packet = (struct unicast_packet *) skb_pull(skb, uni_diff);
+	unicast_packet->packet_type = BAT_UNICAST;
+
+	return skb;
+}
+
+static void frag_create_entry(struct list_head *head, struct sk_buff *skb)
+{
+	struct frag_packet_list_entry *tfp;
+	struct unicast_frag_packet *up =
+		(struct 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 frag_create_buffer(struct list_head *head)
+{
+	int i;
+	struct frag_packet_list_entry *tfp;
+
+	for (i = 0; i < FRAG_BUFFER_SIZE; i++) {
+		tfp = kmalloc(sizeof(struct frag_packet_list_entry),
+			GFP_ATOMIC);
+		if (!tfp) {
+			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 frag_packet_list_entry *frag_search_packet(struct list_head *head,
+						 struct unicast_frag_packet *up)
+{
+	struct frag_packet_list_entry *tfp;
+	struct unicast_frag_packet *tmp_up = NULL;
+	uint16_t search_seqno;
+
+	if (up->flags & UNI_FRAG_HEAD)
+		search_seqno = ntohs(up->seqno)+1;
+	else
+		search_seqno = ntohs(up->seqno)-1;
+
+	list_for_each_entry(tfp, head, list) {
+
+		if (!tfp->skb)
+			continue;
+
+		if (tfp->seqno == ntohs(up->seqno))
+			goto mov_tail;
+
+		tmp_up = (struct unicast_frag_packet *)tfp->skb->data;
+
+		if (tfp->seqno == search_seqno) {
+
+			if ((tmp_up->flags & UNI_FRAG_HEAD) !=
+			    (up->flags & UNI_FRAG_HEAD))
+				return tfp;
+			else
+				goto mov_tail;
+		}
+	}
+	return NULL;
+
+mov_tail:
+	list_move_tail(&tfp->list, head);
+	return NULL;
+}
+
+void frag_list_free(struct list_head *head)
+{
+	struct 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 frag_reassemble_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
+			struct sk_buff **new_skb)
+{
+	struct orig_node *orig_node;
+	struct frag_packet_list_entry *tmp_frag_entry;
+	int ret = NET_RX_DROP;
+	struct unicast_frag_packet *unicast_packet =
+		(struct unicast_frag_packet *)skb->data;
+
+	*new_skb = NULL;
+	spin_lock_bh(&bat_priv->orig_hash_lock);
+	orig_node = ((struct orig_node *)
+		    hash_find(bat_priv->orig_hash, compare_orig, choose_orig,
+			      unicast_packet->orig));
+
+	if (!orig_node) {
+		pr_debug("couldn't find originator in orig_hash\n");
+		goto out;
+	}
+
+	orig_node->last_frag_packet = jiffies;
+
+	if (list_empty(&orig_node->frag_list) &&
+	    frag_create_buffer(&orig_node->frag_list)) {
+		pr_debug("couldn't create frag buffer\n");
+		goto out;
+	}
+
+	tmp_frag_entry = frag_search_packet(&orig_node->frag_list,
+					    unicast_packet);
+
+	if (!tmp_frag_entry) {
+		frag_create_entry(&orig_node->frag_list, skb);
+		ret = NET_RX_SUCCESS;
+		goto out;
+	}
+
+	*new_skb = frag_merge_packet(&orig_node->frag_list, tmp_frag_entry,
+				     skb);
+	/* if not, merge failed */
+	if (*new_skb)
+		ret = NET_RX_SUCCESS;
+out:
+	spin_unlock_bh(&bat_priv->orig_hash_lock);
+
+	return ret;
+}
+
+int frag_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv,
+		  struct batman_if *batman_if, uint8_t dstaddr[])
+{
+	struct unicast_packet tmp_uc, *unicast_packet;
+	struct sk_buff *frag_skb;
+	struct unicast_frag_packet *frag1, *frag2;
+	int uc_hdr_len = sizeof(struct unicast_packet);
+	int ucf_hdr_len = sizeof(struct unicast_frag_packet);
+	int data_len = skb->len;
+
+	if (!bat_priv->primary_if)
+		goto dropped;
+
+	unicast_packet = (struct unicast_packet *) skb->data;
+
+	memcpy(&tmp_uc, unicast_packet, uc_hdr_len);
+	frag_skb = dev_alloc_skb(data_len - (data_len / 2) + ucf_hdr_len);
+	skb_split(skb, frag_skb, data_len / 2);
+
+	if (my_skb_head_push(skb, ucf_hdr_len - uc_hdr_len) < 0 ||
+	    my_skb_head_push(frag_skb, ucf_hdr_len) < 0)
+		goto drop_frag;
+
+	frag1 = (struct unicast_frag_packet *)skb->data;
+	frag2 = (struct unicast_frag_packet *)frag_skb->data;
+
+	memcpy(frag1, &tmp_uc, sizeof(struct unicast_packet));
+
+	frag1->ttl--;
+	frag1->version = COMPAT_VERSION;
+	frag1->packet_type = BAT_UNICAST_FRAG;
+
+	memcpy(frag1->orig, bat_priv->primary_if->net_dev->dev_addr, ETH_ALEN);
+	memcpy(frag2, frag1, sizeof(struct unicast_frag_packet));
+
+	frag1->flags |= UNI_FRAG_HEAD;
+	frag2->flags &= ~UNI_FRAG_HEAD;
+
+	frag1->seqno = htons((uint16_t)atomic_inc_return(
+			     &batman_if->frag_seqno));
+	frag2->seqno = htons((uint16_t)atomic_inc_return(
+			     &batman_if->frag_seqno));
+
+	send_skb_packet(skb, batman_if, dstaddr);
+	send_skb_packet(frag_skb, batman_if, dstaddr);
+	return NET_RX_SUCCESS;
+
+drop_frag:
+	kfree_skb(frag_skb);
+dropped:
+	kfree_skb(skb);
+	return NET_RX_DROP;
+}
+
+int unicast_send_skb(struct sk_buff *skb, struct bat_priv *bat_priv)
+{
+	struct ethhdr *ethhdr = (struct ethhdr *)skb->data;
+	struct unicast_packet *unicast_packet;
+	struct orig_node *orig_node;
+	struct batman_if *batman_if;
+	struct neigh_node *router;
+	int data_len = skb->len;
+	uint8_t dstaddr[6];
+
+	spin_lock_bh(&bat_priv->orig_hash_lock);
+
+	/* get routing information */
+	if (is_multicast_ether_addr(ethhdr->h_dest))
+		orig_node = (struct orig_node *)gw_get_selected(bat_priv);
+	else
+		orig_node = ((struct orig_node *)hash_find(bat_priv->orig_hash,
+							   compare_orig,
+							   choose_orig,
+							   ethhdr->h_dest));
+
+	/* check for hna host */
+	if (!orig_node)
+		orig_node = transtable_search(bat_priv, ethhdr->h_dest);
+
+	router = find_router(bat_priv, orig_node, NULL);
+
+	if (!router)
+		goto unlock;
+
+	/* don't lock while sending the packets ... we therefore
+		* copy the required data before sending */
+
+	batman_if = router->if_incoming;
+	memcpy(dstaddr, router->addr, ETH_ALEN);
+
+	spin_unlock_bh(&bat_priv->orig_hash_lock);
+
+	if (batman_if->if_status != IF_ACTIVE)
+		goto dropped;
+
+	if (my_skb_head_push(skb, sizeof(struct unicast_packet)) < 0)
+		goto dropped;
+
+	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);
+
+	if (atomic_read(&bat_priv->fragmentation) &&
+	    data_len + sizeof(struct unicast_packet) >
+	    batman_if->net_dev->mtu) {
+		/* send frag skb decreases ttl */
+		unicast_packet->ttl++;
+		return frag_send_skb(skb, bat_priv, batman_if,
+				     dstaddr);
+	}
+	send_skb_packet(skb, batman_if, dstaddr);
+	return 0;
+
+unlock:
+	spin_unlock_bh(&bat_priv->orig_hash_lock);
+dropped:
+	kfree_skb(skb);
+	return 1;
+}