[PATCH hyperv-fixes] hv_netvsc: Fix IP header checksum for coalesced packets
From: Haiyang Zhang <hidden>
Date: 2019-02-22 18:26:46
Also in:
linux-hyperv, lkml
Subsystem:
hyper-v/azure core and drivers, networking drivers, the rest · Maintainers:
"K. Y. Srinivasan", Haiyang Zhang, Wei Liu, Dexuan Cui, Long Li, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Haiyang Zhang <haiyangz@microsoft.com> Incoming packets may have IP header checksum verified by the host. They may not have IP header checksum computed after coalescing. This patch re-compute the checksum when necessary, otherwise the packets may be dropped, because Linux network stack always checks it. Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> --- drivers/net/hyperv/netvsc_drv.c | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-)
diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 256adbd044f5..cf4897043e83 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c@@ -744,6 +744,14 @@ void netvsc_linkstatus_callback(struct net_device *net, schedule_delayed_work(&ndev_ctx->dwork, 0); } +static void netvsc_comp_ipcsum(struct sk_buff *skb) +{ + struct iphdr *iph = (struct iphdr *)skb->data; + + iph->check = 0; + iph->check = ip_fast_csum(iph, iph->ihl); +} + static struct sk_buff *netvsc_alloc_recv_skb(struct net_device *net, struct netvsc_channel *nvchan) {
@@ -770,9 +778,17 @@ static struct sk_buff *netvsc_alloc_recv_skb(struct net_device *net, /* skb is already created with CHECKSUM_NONE */ skb_checksum_none_assert(skb); - /* - * In Linux, the IP checksum is always checked. - * Do L4 checksum offload if enabled and present. + /* Incoming packets may have IP header checksum verified by the host. + * They may not have IP header checksum computed after coalescing. + * We compute it here if the flags are set, because on Linux, the IP + * checksum is always checked. + */ + if (csum_info && csum_info->receive.ip_checksum_value_invalid && + csum_info->receive.ip_checksum_succeeded && + skb->protocol == htons(ETH_P_IP)) + netvsc_comp_ipcsum(skb); + + /* Do L4 checksum offload if enabled and present. */ if (csum_info && (net->features & NETIF_F_RXCSUM)) { if (csum_info->receive.tcp_checksum_succeeded ||
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2.19.1