+static int checksum_setup_ipv6(struct xenvif *vif, struct sk_buff *skb,
+ int recalculate_partial_csum)
+{
+ int err = -EPROTO;
+ struct ipv6hdr *ipv6h = (void *)skb->data;
+ u8 nexthdr;
+ unsigned int header_size;
+ unsigned int off;
+ bool fragment;
+ bool done;
+
+ done = false;
+
+ off = sizeof(struct ipv6hdr);
+
+ header_size = skb->network_header + off;
+ maybe_pull_tail(skb, header_size);
+
+ nexthdr = ipv6h->nexthdr;
+
+ while ((off <= sizeof(struct ipv6hdr) + ntohs(ipv6h->payload_len)) &&
+ !done) {
+ switch (nexthdr) {
+ case IPPROTO_DSTOPTS:
+ case IPPROTO_HOPOPTS:
+ case IPPROTO_ROUTING: {
+ struct ipv6_opt_hdr *hp = (void *)(skb->data + off);
+
+ header_size = skb->network_header +
+ off +
+ sizeof(struct ipv6_opt_hdr);
+ maybe_pull_tail(skb, header_size);
+
+ nexthdr = hp->nexthdr;
+ off += ipv6_optlen(hp);
+ break;
+ }
+ case IPPROTO_AH: {
+ struct ip_auth_hdr *hp = (void *)(skb->data + off);
+
+ header_size = skb->network_header +
+ off +
+ sizeof(struct ip_auth_hdr);
+ maybe_pull_tail(skb, header_size);
+
+ nexthdr = hp->nexthdr;
+ off += (hp->hdrlen+2)<<2;
+ break;
+ }
+ case IPPROTO_FRAGMENT:
+ fragment = true;
+ /* fall through */
+ default:
+ done = true;
+ break;
+ }
+ }
+
+ if (!done) {
+ if (net_ratelimit())
+ netdev_err(vif->dev, "Failed to parse packet header\n");
+ goto out;
+ }
+
+ if (fragment) {
+ if (net_ratelimit())
+ netdev_err(vif->dev, "Packet is a fragment!\n");
+ goto out;
+ }
+
+ switch (nexthdr) {
+ case IPPROTO_TCP:
+ if (!skb_partial_csum_set(skb, off,
+ offsetof(struct tcphdr, check)))
+ goto out;
+
+ if (recalculate_partial_csum) {
+ struct tcphdr *tcph = tcp_hdr(skb);
+
+ header_size = skb->network_header +
+ off +
+ sizeof(struct tcphdr);
+ maybe_pull_tail(skb, header_size);
+
+ tcph->check = ~csum_ipv6_magic(&ipv6h->saddr,
+ &ipv6h->daddr,
+ skb->len - off,
+ IPPROTO_TCP, 0);
+ }
+ break;
+ case IPPROTO_UDP:
+ if (!skb_partial_csum_set(skb, off,
+ offsetof(struct udphdr, check)))
+ goto out;
+
+ if (recalculate_partial_csum) {
+ struct udphdr *udph = udp_hdr(skb);
+
+ header_size = skb->network_header +
+ off +
+ sizeof(struct udphdr);
+ maybe_pull_tail(skb, header_size);
+
+ udph->check = ~csum_ipv6_magic(&ipv6h->saddr,
+ &ipv6h->daddr,
+ skb->len - off,
+ IPPROTO_UDP, 0);
+ }
+ break;
+ default:
+ if (net_ratelimit())
+ netdev_err(vif->dev,
+ "Attempting to checksum a non-TCP/UDP packet, "
+ "dropping a protocol %d packet\n",
+ nexthdr);
+ goto out;
+ }
+
+ err = 0;
+
+out:
+ return err;
+}
+
+static int checksum_setup(struct xenvif *vif, struct sk_buff *skb)
+{
+ int err = -EPROTO;
+ int recalculate_partial_csum = 0;
+
+ /* A GSO SKB must be CHECKSUM_PARTIAL. However some buggy
+ * peers can fail to set NETRXF_csum_blank when sending a GSO
+ * frame. In this case force the SKB to CHECKSUM_PARTIAL and
+ * recalculate the partial checksum.
+ */
+ if (skb->ip_summed != CHECKSUM_PARTIAL && skb_is_gso(skb)) {
+ vif->rx_gso_checksum_fixup++;
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ recalculate_partial_csum = 1;
+ }
+
+ /* A non-CHECKSUM_PARTIAL SKB does not require setup. */
+ if (skb->ip_summed != CHECKSUM_PARTIAL)
+ return 0;
+
+ if (skb->protocol == htons(ETH_P_IP))
+ err = checksum_setup_ip(vif, skb, recalculate_partial_csum);
+ else if (skb->protocol == htons(ETH_P_IPV6))
+ err = checksum_setup_ipv6(vif, skb, recalculate_partial_csum);
+
+ return err;
+}
+