From 62a02c98ce03bb214009509a4802b7b63f59621c Mon Sep 17 00:00:00 2001 From: Fugang Duan Date: Wed, 18 Jun 2014 08:33:52 +0800 Subject: [PATCH] net: fec: Don't clear IPV6 header checksum field when IP accelerator enable The commit 96c50caa5148 (net: fec: Enable IP header hardware checksum) enable HW IP header checksum for IPV4 and IPV6, which causes IPV6 TCP/UDP cannot work. (The issue is reported by Russell King) For FEC IP header checksum function: Insert IP header checksum. This "IINS" bit is written by the user. If set, IP accelerator calculates the IP header checksum and overwrites the IINS corresponding header field with the calculated value. The checksum field must be cleared by user, otherwise the checksum always is 0xFFFF. So the previous patch clear IP header checksum field regardless of IP frame type. In fact, IP HW detect the packet as IPV6 type, even if the "IINS" bit is set, the IP accelerator is not triggered to calculates IPV6 header checksum because IPV6 frame format don't have checksum. So this results in the IPV6 frame being corrupted. The patch just add software detect the current packet type, if it is IPV6 frame, it don't clear IP header checksum field. Cc: Russell King Reported-and-tested-by: Russell King Signed-off-by: Fugang Duan Signed-off-by: David S. Miller --- drivers/net/ethernet/freescale/fec_main.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c index 38d9d276ab8b..77037fd377b8 100644 --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -320,6 +320,11 @@ static void *swap_buffer(void *bufaddr, int len) return bufaddr; } +static inline bool is_ipv4_pkt(struct sk_buff *skb) +{ + return skb->protocol == htons(ETH_P_IP) && ip_hdr(skb)->version == 4; +} + static int fec_enet_clear_csum(struct sk_buff *skb, struct net_device *ndev) { @@ -330,7 +335,8 @@ fec_enet_clear_csum(struct sk_buff *skb, struct net_device *ndev) if (unlikely(skb_cow_head(skb, 0))) return -1; - ip_hdr(skb)->check = 0; + if (is_ipv4_pkt(skb)) + ip_hdr(skb)->check = 0; *(__sum16 *)(skb->head + skb->csum_start + skb->csum_offset) = 0; return 0; -- 2.20.1