[PATCH v2 1/1] net: macb: initialize checksum when using checksum offloading
From: Helmut Buchsbaum <hidden>
Date: 2016-08-29 13:58:08
Subsystem:
atmel macb ethernet driver, networking drivers, the rest · Maintainers:
Théo Lebrun, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
MACB/GEM needs the checksum field initialized to 0 to get correct results on transmit in all cases, e.g. on Zynq, UDP packets with payload <= 2 otherwise contain a wrong checksums. Signed-off-by: Helmut Buchsbaum <redacted> --- drivers/net/ethernet/cadence/macb.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)
diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
index 89c0cfa..de2f791 100644
--- a/drivers/net/ethernet/cadence/macb.c
+++ b/drivers/net/ethernet/cadence/macb.c@@ -1323,6 +1323,19 @@ dma_error: return 0; } +static inline void macb_clear_csum(struct sk_buff *skb) +{ + /* no change for packets without checksum offloading */ + if (skb->ip_summed != CHECKSUM_PARTIAL) + return; + + /* 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->head + skb->csum_start + skb->csum_offset) = 0; +} + static int macb_start_xmit(struct sk_buff *skb, struct net_device *dev) { u16 queue_index = skb_get_queue_mapping(skb);
@@ -1362,6 +1375,8 @@ static int macb_start_xmit(struct sk_buff *skb, struct net_device *dev) return NETDEV_TX_BUSY; } + macb_clear_csum(skb); + /* Map socket buffer for DMA transfer */ if (!macb_tx_map(bp, queue, skb)) { dev_kfree_skb_any(skb);
--
2.1.4