vio(4) add recv TCP/UDP checksum offloading

tested on Linux/KVM
tested on proxmox and vultr by florian

ok florian

diff --git a/sys/dev/pv/if_vio.c b/sys/dev/pv/if_vio.c
index 7b89523..5c9a05f 100644 (file)
--- a/sys/dev/pv/if_vio.c
+++ b/sys/dev/pv/if_vio.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_vio.c,v 1.26 2023/11/10 15:51:24 bluhm Exp $       */
+/*     $OpenBSD: if_vio.c,v 1.27 2023/12/09 10:36:05 jan Exp $ */
 
 /*
  * Copyright (c) 2012 Stefan Fritsch, Alexander Fiveg.
@@ -145,6 +145,7 @@ struct virtio_net_hdr {
 } __packed;
 
 #define VIRTIO_NET_HDR_F_NEEDS_CSUM    1 /* flags */
+#define VIRTIO_NET_HDR_F_DATA_VALID    2 /* flags */
 #define VIRTIO_NET_HDR_GSO_NONE                0 /* gso_type */
 #define VIRTIO_NET_HDR_GSO_TCPV4       1 /* gso_type */
 #define VIRTIO_NET_HDR_GSO_UDP         3 /* gso_type */
@@ -533,7 +534,7 @@ vio_attach(struct device *parent, struct device *self, void *aux)
        vsc->sc_driver_features = VIRTIO_NET_F_MAC | VIRTIO_NET_F_STATUS |
            VIRTIO_NET_F_CTRL_VQ | VIRTIO_NET_F_CTRL_RX |
            VIRTIO_NET_F_MRG_RXBUF | VIRTIO_NET_F_CSUM |
-           VIRTIO_F_RING_EVENT_IDX;
+           VIRTIO_F_RING_EVENT_IDX | VIRTIO_NET_F_GUEST_CSUM;
 
        virtio_negotiate_features(vsc, virtio_net_feature_names);
        if (virtio_has_feature(vsc, VIRTIO_NET_F_MAC)) {
@@ -986,6 +987,31 @@ vio_populate_rx_mbufs(struct vio_softc *sc)
        timeout_add_sec(&sc->sc_rxtick, 1);
 }
 
+void
+vio_rx_offload(struct mbuf *m, struct virtio_net_hdr *hdr)
+{
+       struct ether_extracted ext;
+
+       if (!ISSET(hdr->flags, VIRTIO_NET_HDR_F_DATA_VALID) &&
+           !ISSET(hdr->flags, VIRTIO_NET_HDR_F_NEEDS_CSUM))
+               return;
+
+       ether_extract_headers(m, &ext);
+
+       if (ext.ip4)
+               SET(m->m_pkthdr.csum_flags, M_IPV4_CSUM_IN_OK);
+
+       if (ext.tcp) {
+               SET(m->m_pkthdr.csum_flags, M_TCP_CSUM_IN_OK);
+               if (ISSET(hdr->flags, VIRTIO_NET_HDR_F_NEEDS_CSUM))
+                       SET(m->m_pkthdr.csum_flags, M_TCP_CSUM_OUT);
+       } else if (ext.udp) {
+               SET(m->m_pkthdr.csum_flags, M_UDP_CSUM_IN_OK);
+               if (ISSET(hdr->flags, VIRTIO_NET_HDR_F_NEEDS_CSUM))
+                       SET(m->m_pkthdr.csum_flags, M_UDP_CSUM_OUT);
+       }
+}
+
 /* dequeue received packets */
 int
 vio_rxeof(struct vio_softc *sc)
@@ -1019,6 +1045,8 @@ vio_rxeof(struct vio_softc *sc)
                                bufs_left = hdr->num_buffers - 1;
                        else
                                bufs_left = 0;
+                       if (virtio_has_feature(vsc, VIRTIO_NET_F_GUEST_CSUM))
+                               vio_rx_offload(m, hdr);
                } else {
                        m->m_flags &= ~M_PKTHDR;
                        m0->m_pkthdr.len += m->m_len;