diff options
| -rw-r--r-- | drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c | 26 |
1 files changed, 16 insertions, 10 deletions
diff --git a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c index 40d7e0c615f9..4f93355e9a93 100644 --- a/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c +++ b/drivers/net/ethernet/qualcomm/rmnet/rmnet_map_data.c @@ -120,27 +120,33 @@ rmnet_map_ipv6_dl_csum_trailer(struct sk_buff *skb, struct rmnet_map_dl_csum_trailer *csum_trailer, struct rmnet_priv *priv) { - __sum16 *csum_field, ip6_payload_csum, pseudo_csum, csum_temp; + struct ipv6hdr *ip6h = (struct ipv6hdr *)skb->data; + void *txporthdr = skb->data + sizeof(*ip6h); + __sum16 *csum_field, pseudo_csum, csum_temp; u16 csum_value, csum_value_final; __be16 ip6_hdr_csum, addend; - struct ipv6hdr *ip6h; - void *txporthdr; + __sum16 ip6_payload_csum; + __be16 ip_header_csum; u32 length; - ip6h = (struct ipv6hdr *)(skb->data); - - txporthdr = skb->data + sizeof(struct ipv6hdr); + /* Checksum offload is only supported for UDP and TCP protocols; + * the packet cannot include any IPv6 extension headers + */ csum_field = rmnet_map_get_csum_field(ip6h->nexthdr, txporthdr); - if (!csum_field) { priv->stats.csum_err_invalid_transport++; return -EPROTONOSUPPORT; } + /* The checksum value in the trailer is computed over the entire + * IP packet, including the IP header and payload. To derive the + * transport checksum from this, we first subract the contribution + * of the IP header from the trailer checksum. We then add the + * checksum computed over the pseudo header. + */ csum_value = ~ntohs(csum_trailer->csum_value); - ip6_hdr_csum = (__force __be16) - ~ntohs((__force __be16)ip_compute_csum(ip6h, - (int)(txporthdr - (void *)(skb->data)))); + ip_header_csum = (__force __be16)ip_fast_csum(ip6h, sizeof(*ip6h) / 4); + ip6_hdr_csum = (__force __be16)~ntohs(ip_header_csum); ip6_payload_csum = csum16_sub((__force __sum16)csum_value, ip6_hdr_csum); |