diff options
| -rw-r--r-- | hw/net/vmxnet3.c | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c index dd22a0a8cd..59b06b8412 100644 --- a/hw/net/vmxnet3.c +++ b/hw/net/vmxnet3.c @@ -885,6 +885,63 @@ vmxnet3_get_next_rx_descr(VMXNET3State *s, bool is_head, } } +/* In case packet was csum offloaded (either NEEDS_CSUM or DATA_VALID), + * the implementation always passes an RxCompDesc with a "Checksum + * calculated and found correct" to the OS (cnc=0 and tuc=1, see + * vmxnet3_rx_update_descr). This emulates the observed ESXi behavior. + * + * Therefore, if packet has the NEEDS_CSUM set, we must calculate + * and place a fully computed checksum into the tcp/udp header. + * Otherwise, the OS driver will receive a checksum-correct indication + * (CHECKSUM_UNNECESSARY), but with the actual tcp/udp checksum field + * having just the pseudo header csum value. + * + * While this is not a problem if packet is destined for local delivery, + * in the case the host OS performs forwarding, it will forward an + * incorrectly checksummed packet. + */ +static void vmxnet3_rx_need_csum_calculate(struct VmxnetRxPkt *pkt, + const void *pkt_data, + size_t pkt_len) +{ + struct virtio_net_hdr *vhdr; + bool isip4, isip6, istcp, isudp; + uint8_t *data; + int len; + + if (!vmxnet_rx_pkt_has_virt_hdr(pkt)) { + return; + } + + vhdr = vmxnet_rx_pkt_get_vhdr(pkt); + if (!VMXNET_FLAG_IS_SET(vhdr->flags, VIRTIO_NET_HDR_F_NEEDS_CSUM)) { + return; + } + + vmxnet_rx_pkt_get_protocols(pkt, &isip4, &isip6, &isudp, &istcp); + if (!(isip4 || isip6) || !(istcp || isudp)) { + return; + } + + vmxnet3_dump_virt_hdr(vhdr); + + /* Validate packet len: csum_start + scum_offset + length of csum field */ + if (pkt_len < (vhdr->csum_start + vhdr->csum_offset + 2)) { + VMW_PKPRN("packet len:%d < csum_start(%d) + csum_offset(%d) + 2, " + "cannot calculate checksum", + len, vhdr->csum_start, vhdr->csum_offset); + return; + } + + data = (uint8_t *)pkt_data + vhdr->csum_start; + len = pkt_len - vhdr->csum_start; + /* Put the checksum obtained into the packet */ + stw_be_p(data + vhdr->csum_offset, net_raw_checksum(data, len)); + + vhdr->flags &= ~VIRTIO_NET_HDR_F_NEEDS_CSUM; + vhdr->flags |= VIRTIO_NET_HDR_F_DATA_VALID; +} + static void vmxnet3_rx_update_descr(struct VmxnetRxPkt *pkt, struct Vmxnet3_RxCompDesc *rxcd) { @@ -1898,6 +1955,7 @@ vmxnet3_receive(NetClientState *nc, const uint8_t *buf, size_t size) if (vmxnet3_rx_filter_may_indicate(s, buf, size)) { vmxnet_rx_pkt_set_protocols(s->rx_pkt, buf, size); + vmxnet3_rx_need_csum_calculate(s->rx_pkt, buf, size); vmxnet_rx_pkt_attach_data(s->rx_pkt, buf, size, s->rx_vlan_stripping); bytes_indicated = vmxnet3_indicate_packet(s) ? size : -1; if (bytes_indicated < size) { |