if the NIC fails to validate the checksum on TCP/UDP, and validation of IP
checksum is successful, the driver subtracts the pseudo-header checksum
from the value obtained by the hardware and sets CHECKSUM_COMPLETE. Don't
do that if protocol is IPPROTO_SCTP, otherwise CRC32c validation fails.

Reported-by: Shuang Li <shu...@redhat.com>
Fixes: f8c6455bb04b ("net/mlx4_en: Extend checksum offloading by CHECKSUM 
COMPLETE")
Signed-off-by: Davide Caratti <dcara...@redhat.com>
---
 drivers/net/ethernet/mellanox/mlx4/en_rx.c | 33 +++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 12 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c 
b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
index 77abd18..d9293e4 100644
--- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
@@ -572,16 +572,21 @@ static inline __wsum get_fixed_vlan_csum(__wsum 
hw_checksum,
  * header, the HW adds it. To address that, we are subtracting the pseudo
  * header checksum from the checksum value provided by the HW.
  */
-static void get_fixed_ipv4_csum(__wsum hw_checksum, struct sk_buff *skb,
-                               struct iphdr *iph)
+static int get_fixed_ipv4_csum(__wsum hw_checksum, struct sk_buff *skb,
+                              struct iphdr *iph)
 {
        __u16 length_for_csum = 0;
        __wsum csum_pseudo_header = 0;
+       __u8 ipproto = iph->protocol;
+
+       if (ipproto == IPPROTO_SCTP)
+               return -1;
 
        length_for_csum = (be16_to_cpu(iph->tot_len) - (iph->ihl << 2));
        csum_pseudo_header = csum_tcpudp_nofold(iph->saddr, iph->daddr,
-                                               length_for_csum, iph->protocol, 
0);
+                                               length_for_csum, ipproto, 0);
        skb->csum = csum_sub(hw_checksum, csum_pseudo_header);
+       return 0;
 }
 
 #if IS_ENABLED(CONFIG_IPV6)
@@ -592,17 +597,20 @@ static void get_fixed_ipv4_csum(__wsum hw_checksum, 
struct sk_buff *skb,
 static int get_fixed_ipv6_csum(__wsum hw_checksum, struct sk_buff *skb,
                               struct ipv6hdr *ipv6h)
 {
+       __u8 nexthdr = ipv6h->nexthdr;
        __wsum csum_pseudo_hdr = 0;
 
-       if (unlikely(ipv6h->nexthdr == IPPROTO_FRAGMENT ||
-                    ipv6h->nexthdr == IPPROTO_HOPOPTS))
+       if (unlikely(nexthdr == IPPROTO_FRAGMENT ||
+                    nexthdr == IPPROTO_HOPOPTS ||
+                    nexthdr == IPPROTO_SCTP))
                return -1;
-       hw_checksum = csum_add(hw_checksum, (__force 
__wsum)htons(ipv6h->nexthdr));
+       hw_checksum = csum_add(hw_checksum, (__force __wsum)htons(nexthdr));
 
        csum_pseudo_hdr = csum_partial(&ipv6h->saddr,
                                       sizeof(ipv6h->saddr) + 
sizeof(ipv6h->daddr), 0);
        csum_pseudo_hdr = csum_add(csum_pseudo_hdr, (__force 
__wsum)ipv6h->payload_len);
-       csum_pseudo_hdr = csum_add(csum_pseudo_hdr, (__force 
__wsum)ntohs(ipv6h->nexthdr));
+       csum_pseudo_hdr = csum_add(csum_pseudo_hdr,
+                                  (__force __wsum)htons(nexthdr));
 
        skb->csum = csum_sub(hw_checksum, csum_pseudo_hdr);
        skb->csum = csum_add(skb->csum, csum_partial(ipv6h, sizeof(struct 
ipv6hdr), 0));
@@ -624,12 +632,13 @@ static int check_csum(struct mlx4_cqe *cqe, struct 
sk_buff *skb, void *va,
                hdr += sizeof(struct vlan_hdr);
        }
 
-       if (cqe->status & cpu_to_be16(MLX4_CQE_STATUS_IPV4))
-               get_fixed_ipv4_csum(hw_checksum, skb, hdr);
+       if ((cqe->status & cpu_to_be16(MLX4_CQE_STATUS_IPV4)) &&
+           (unlikely(get_fixed_ipv4_csum(hw_checksum, skb, hdr))))
+               return -1;
 #if IS_ENABLED(CONFIG_IPV6)
-       else if (cqe->status & cpu_to_be16(MLX4_CQE_STATUS_IPV6))
-               if (unlikely(get_fixed_ipv6_csum(hw_checksum, skb, hdr)))
-                       return -1;
+       else if ((cqe->status & cpu_to_be16(MLX4_CQE_STATUS_IPV6)) &&
+                (unlikely(get_fixed_ipv6_csum(hw_checksum, skb, hdr))))
+               return -1;
 #endif
        return 0;
 }
-- 
2.9.4

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