diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c index 89c0cfa9719f..d954a97b0b0b 100644 --- a/drivers/net/ethernet/cadence/macb.c +++ b/drivers/net/ethernet/cadence/macb.c @@ -1323,6 +1323,24 @@ dma_error: return 0; } +static inline int macb_clear_csum(struct sk_buff *skb) +{ + /* no change for packets without checksum offloading */ + if (skb->ip_summed != CHECKSUM_PARTIAL) + return 0; + + /* make sure we can modify the header */ + if (unlikely(skb_cow_head(skb, 0))) + return -1; + + /* initialize checksum field + * This is required - at least for Zynq, which otherwise calculates + * wrong UDP header checksums for UDP packets with UDP data len <=2 + */ + *(__sum16 *)(skb_checksum_start(skb) + skb->csum_offset) = 0; + return 0; +} + static int macb_start_xmit(struct sk_buff *skb, struct net_device *dev) { u16 queue_index = skb_get_queue_mapping(skb); @@ -1362,6 +1380,11 @@ static int macb_start_xmit(struct sk_buff *skb, struct net_device *dev) return NETDEV_TX_BUSY; } + if (macb_clear_csum(skb)) { + dev_kfree_skb_any(skb); + return NETDEV_TX_OK; + } + /* Map socket buffer for DMA transfer */ if (!macb_tx_map(bp, queue, skb)) { dev_kfree_skb_any(skb);