diff --git a/net/batman-adv/fragmentation.c b/net/batman-adv/fragmentation.c index 11149e5be4e0..106bda56ec98 100644 --- a/net/batman-adv/fragmentation.c +++ b/net/batman-adv/fragmentation.c @@ -404,7 +404,7 @@ bool batadv_frag_skb_fwd(struct sk_buff *skb, * batadv_frag_create - create a fragment from skb * @skb: skb to create fragment from * @frag_head: header to use in new fragment - * @mtu: size of new fragment + * @fragment_size: size of new fragment * * Split the passed skb into two fragments: A new one with size matching the * passed mtu and the old one with the rest. The new skb contains data from the @@ -414,11 +414,11 @@ bool batadv_frag_skb_fwd(struct sk_buff *skb, */ static struct sk_buff *batadv_frag_create(struct sk_buff *skb, struct batadv_frag_packet *frag_head, - unsigned int mtu) + unsigned int fragment_size) { struct sk_buff *skb_fragment; unsigned int header_size = sizeof(*frag_head); - unsigned int fragment_size = mtu - header_size; + unsigned int mtu = fragment_size + header_size; skb_fragment = netdev_alloc_skb(NULL, mtu + ETH_HLEN); if (!skb_fragment) @@ -456,7 +456,7 @@ int batadv_frag_send_packet(struct sk_buff *skb, struct sk_buff *skb_fragment; 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; + unsigned int max_fragment_size, num_fragments; int ret; /* To avoid merge and refragmentation at next-hops we never send @@ -464,10 +464,15 @@ int batadv_frag_send_packet(struct sk_buff *skb, */ mtu = min_t(unsigned int, mtu, BATADV_FRAG_MAX_FRAG_SIZE); max_fragment_size = mtu - header_size; - max_packet_size = max_fragment_size * BATADV_FRAG_MAX_FRAGMENTS; + + if (skb->len == 0 || max_fragment_size == 0) + return -EINVAL; + + num_fragments = (skb->len - 1) / max_fragment_size + 1; + max_fragment_size = (skb->len - 1) / num_fragments + 1; /* Don't even try to fragment, if we need more than 16 fragments */ - if (skb->len > max_packet_size) { + if (num_fragments > BATADV_FRAG_MAX_FRAGMENTS) { ret = -EAGAIN; goto free_skb; } @@ -507,7 +512,8 @@ int batadv_frag_send_packet(struct sk_buff *skb, goto put_primary_if; } - skb_fragment = batadv_frag_create(skb, &frag_header, mtu); + skb_fragment = batadv_frag_create(skb, &frag_header, + max_fragment_size); if (!skb_fragment) { ret = -ENOMEM; goto put_primary_if;