hw/net: Added CSO for IPv6

Added fix for checksum offload for IPv6 if a backend doesn't
have a virtual header.
This patch is a part of IPv6 fragmentation.

Signed-off-by: Andrew Melnychenko <[email protected]>
Signed-off-by: Jason Wang <[email protected]>

Author: AndrewAtDaynix

hw/net/net_tx_pkt.c

@@ -468,18 +468,27 @@ static void net_tx_pkt_do_sw_csum(struct NetTxPkt *pkt)
     /* num of iovec without vhdr */
     uint32_t iov_len = pkt->payload_frags + NET_TX_PKT_PL_START_FRAG - 1;
     uint16_t csl;
-    struct ip_header *iphdr;
     size_t csum_offset = pkt->virt_hdr.csum_start + pkt->virt_hdr.csum_offset;
+    uint16_t l3_proto = eth_get_l3_proto(iov, 1, iov->iov_len);
 
     /* Put zero to checksum field */
     iov_from_buf(iov, iov_len, csum_offset, &csum, sizeof csum);
 
     /* Calculate L4 TCP/UDP checksum */
     csl = pkt->payload_len;
 
+    csum_cntr = 0;
+    cso = 0;
     /* add pseudo header to csum */
-    iphdr = pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_base;
-    csum_cntr = eth_calc_ip4_pseudo_hdr_csum(iphdr, csl, &cso);
+    if (l3_proto == ETH_P_IP) {
+        csum_cntr = eth_calc_ip4_pseudo_hdr_csum(
+                pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_base,
+                csl, &cso);
+    } else if (l3_proto == ETH_P_IPV6) {
+        csum_cntr = eth_calc_ip6_pseudo_hdr_csum(
+                pkt->vec[NET_TX_PKT_L3HDR_FRAG].iov_base,
+                csl, pkt->l4proto, &cso);
+    }
 
     /* data checksum */
     csum_cntr +=