1 files changed, 478 insertions, 0 deletions

diff --git a/net/batman-adv/unicast.c b/net/batman-adv/unicast.c
new file mode 100644
index 00000000..0bb3b598
--- /dev/null
+++ b/net/batman-adv/unicast.c
@@ -0,0 +1,478 @@
+/* Copyright (C) 2010-2013 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;
+	bool 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;
+}