1 files changed, 49 insertions, 33 deletions

diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c
index 0934730fb7ff..9c561e683f4b 100644
--- a/net/batman-adv/fragmentation.c
+++ b/net/batman-adv/fragmentation.c
@@ -20,6 +20,7 @@
 
 #include <linux/atomic.h>
 #include <linux/byteorder/generic.h>
+#include <linux/errno.h>
 #include <linux/etherdevice.h>
 #include <linux/fs.h>
 #include <linux/if_ether.h>
@@ -42,17 +43,23 @@
 /**
  * batadv_frag_clear_chain - delete entries in the fragment buffer chain
  * @head: head of chain with entries.
+ * @dropped: whether the chain is cleared because all fragments are dropped
  *
  * Free fragments in the passed hlist. Should be called with appropriate lock.
  */
-static void batadv_frag_clear_chain(struct hlist_head *head)
+static void batadv_frag_clear_chain(struct hlist_head *head, bool dropped)
 {
 	struct batadv_frag_list_entry *entry;
 	struct hlist_node *node;
 
 	hlist_for_each_entry_safe(entry, node, head, list) {
 		hlist_del(&entry->list);
-		kfree_skb(entry->skb);
+
+		if (dropped)
+			kfree_skb(entry->skb);
+		else
+			consume_skb(entry->skb);
+
 		kfree(entry);
 	}
 }
@@ -73,7 +80,7 @@ void batadv_frag_purge_orig(struct batadv_orig_node *orig_node,
 		spin_lock_bh(&chain->lock);
 
 		if (!check_cb || check_cb(chain)) {
-			batadv_frag_clear_chain(&chain->head);
+			batadv_frag_clear_chain(&chain->fragment_list, true);
 			chain->size = 0;
 		}
 
@@ -117,8 +124,8 @@ static bool batadv_frag_init_chain(struct batadv_frag_table_entry *chain,
 	if (chain->seqno == seqno)
 		return false;
 
-	if (!hlist_empty(&chain->head))
-		batadv_frag_clear_chain(&chain->head);
+	if (!hlist_empty(&chain->fragment_list))
+		batadv_frag_clear_chain(&chain->fragment_list, true);
 
 	chain->size = 0;
 	chain->seqno = seqno;
@@ -176,7 +183,7 @@ static bool batadv_frag_insert_packet(struct batadv_orig_node *orig_node,
 	chain = &orig_node->fragments[bucket];
 	spin_lock_bh(&chain->lock);
 	if (batadv_frag_init_chain(chain, seqno)) {
-		hlist_add_head(&frag_entry_new->list, &chain->head);
+		hlist_add_head(&frag_entry_new->list, &chain->fragment_list);
 		chain->size = skb->len - hdr_size;
 		chain->timestamp = jiffies;
 		chain->total_size = ntohs(frag_packet->total_size);
@@ -185,7 +192,7 @@ static bool batadv_frag_insert_packet(struct batadv_orig_node *orig_node,
 	}
 
 	/* Find the position for the new fragment. */
-	hlist_for_each_entry(frag_entry_curr, &chain->head, list) {
+	hlist_for_each_entry(frag_entry_curr, &chain->fragment_list, list) {
 		/* Drop packet if fragment already exists. */
 		if (frag_entry_curr->no == frag_entry_new->no)
 			goto err_unlock;
@@ -220,11 +227,11 @@ out:
 		 * exceeds the maximum size of one merged packet. Don't allow
 		 * packets to have different total_size.
 		 */
-		batadv_frag_clear_chain(&chain->head);
+		batadv_frag_clear_chain(&chain->fragment_list, true);
 		chain->size = 0;
 	} else if (ntohs(frag_packet->total_size) == chain->size) {
 		/* All fragments received. Hand over chain to caller. */
-		hlist_move_list(&chain->head, chain_out);
+		hlist_move_list(&chain->fragment_list, chain_out);
 		chain->size = 0;
 	}
 
@@ -252,8 +259,9 @@ batadv_frag_merge_packets(struct hlist_head *chain)
 {
 	struct batadv_frag_packet *packet;
 	struct batadv_frag_list_entry *entry;
-	struct sk_buff *skb_out = NULL;
+	struct sk_buff *skb_out;
 	int size, hdr_size = sizeof(struct batadv_frag_packet);
+	bool dropped = false;
 
 	/* Remove first entry, as this is the destination for the rest of the
 	 * fragments.
@@ -270,6 +278,7 @@ batadv_frag_merge_packets(struct hlist_head *chain)
 	if (pskb_expand_head(skb_out, 0, size - skb_out->len, GFP_ATOMIC) < 0) {
 		kfree_skb(skb_out);
 		skb_out = NULL;
+		dropped = true;
 		goto free;
 	}
 
@@ -291,7 +300,7 @@ batadv_frag_merge_packets(struct hlist_head *chain)
 
 free:
 	/* Locking is not needed, because 'chain' is not part of any orig. */
-	batadv_frag_clear_chain(chain);
+	batadv_frag_clear_chain(chain, dropped);
 	return skb_out;
 }
 
@@ -352,7 +361,7 @@ bool batadv_frag_skb_fwd(struct sk_buff *skb,
 			 struct batadv_orig_node *orig_node_src)
 {
 	struct batadv_priv *bat_priv = netdev_priv(recv_if->soft_iface);
-	struct batadv_orig_node *orig_node_dst = NULL;
+	struct batadv_orig_node *orig_node_dst;
 	struct batadv_neigh_node *neigh_node = NULL;
 	struct batadv_frag_packet *packet;
 	u16 total_size;
@@ -433,8 +442,7 @@ err:
  * @orig_node: final destination of the created fragments
  * @neigh_node: next-hop of the created fragments
  *
- * Return: the netdev tx status or -1 in case of error.
- * When -1 is returned the skb is not consumed.
+ * Return: the netdev tx status or a negative errno code on a failure
  */
 int batadv_frag_send_packet(struct sk_buff *skb,
 			    struct batadv_orig_node *orig_node,
@@ -447,7 +455,7 @@ int batadv_frag_send_packet(struct sk_buff *skb,
 	unsigned int mtu = neigh_node->if_incoming->net_dev->mtu;
 	unsigned int header_size = sizeof(frag_header);
 	unsigned int max_fragment_size, max_packet_size;
-	int ret = -1;
+	int ret;
 
 	/* To avoid merge and refragmentation at next-hops we never send
 	 * fragments larger than BATADV_FRAG_MAX_FRAG_SIZE
@@ -457,13 +465,17 @@ int batadv_frag_send_packet(struct sk_buff *skb,
 	max_packet_size = max_fragment_size * BATADV_FRAG_MAX_FRAGMENTS;
 
 	/* Don't even try to fragment, if we need more than 16 fragments */
-	if (skb->len > max_packet_size)
-		goto out;
+	if (skb->len > max_packet_size) {
+		ret = -EAGAIN;
+		goto free_skb;
+	}
 
 	bat_priv = orig_node->bat_priv;
 	primary_if = batadv_primary_if_get_selected(bat_priv);
-	if (!primary_if)
-		goto out;
+	if (!primary_if) {
+		ret = -EINVAL;
+		goto put_primary_if;
+	}
 
 	/* Create one header to be copied to all fragments */
 	frag_header.packet_type = BATADV_UNICAST_FRAG;
@@ -488,34 +500,35 @@ int batadv_frag_send_packet(struct sk_buff *skb,
 	/* Eat and send fragments from the tail of skb */
 	while (skb->len > max_fragment_size) {
 		skb_fragment = batadv_frag_create(skb, &frag_header, mtu);
-		if (!skb_fragment)
-			goto out;
+		if (!skb_fragment) {
+			ret = -ENOMEM;
+			goto free_skb;
+		}
 
 		batadv_inc_counter(bat_priv, BATADV_CNT_FRAG_TX);
 		batadv_add_counter(bat_priv, BATADV_CNT_FRAG_TX_BYTES,
 				   skb_fragment->len + ETH_HLEN);
 		ret = batadv_send_unicast_skb(skb_fragment, neigh_node);
 		if (ret != NET_XMIT_SUCCESS) {
-			/* return -1 so that the caller can free the original
-			 * skb
-			 */
-			ret = -1;
-			goto out;
+			ret = NET_XMIT_DROP;
+			goto free_skb;
 		}
 
 		frag_header.no++;
 
 		/* The initial check in this function should cover this case */
 		if (frag_header.no == BATADV_FRAG_MAX_FRAGMENTS - 1) {
-			ret = -1;
-			goto out;
+			ret = -EINVAL;
+			goto free_skb;
 		}
 	}
 
 	/* Make room for the fragment header. */
 	if (batadv_skb_head_push(skb, header_size) < 0 ||
-	    pskb_expand_head(skb, header_size + ETH_HLEN, 0, GFP_ATOMIC) < 0)
-		goto out;
+	    pskb_expand_head(skb, header_size + ETH_HLEN, 0, GFP_ATOMIC) < 0) {
+		ret = -ENOMEM;
+		goto free_skb;
+	}
 
 	memcpy(skb->data, &frag_header, header_size);
 
@@ -524,10 +537,13 @@ int batadv_frag_send_packet(struct sk_buff *skb,
 	batadv_add_counter(bat_priv, BATADV_CNT_FRAG_TX_BYTES,
 			   skb->len + ETH_HLEN);
 	ret = batadv_send_unicast_skb(skb, neigh_node);
+	/* skb was consumed */
+	skb = NULL;
 
-out:
-	if (primary_if)
-		batadv_hardif_put(primary_if);
+put_primary_if:
+	batadv_hardif_put(primary_if);
+free_skb:
+	kfree_skb(skb);
 
 	return ret;
 }