vio: Support checksum offloading for IPv4 TX

"Looks good to me" brad@

diff --git a/sys/dev/pci/if_vio.c b/sys/dev/pci/if_vio.c
index 316e742..9a297e1 100644 (file)
--- a/sys/dev/pci/if_vio.c
+++ b/sys/dev/pci/if_vio.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: if_vio.c,v 1.28 2015/04/24 12:53:35 sf Exp $  */
+/*     $OpenBSD: if_vio.c,v 1.29 2015/04/26 12:19:24 sf Exp $  */
 
 /*
  * Copyright (c) 2012 Stefan Fritsch, Alexander Fiveg.
@@ -49,6 +49,9 @@
 
 #include <netinet/in.h>
 #include <netinet/if_ether.h>
+#include <netinet/ip.h>
+#include <netinet/tcp.h>
+#include <netinet/udp.h>
 
 #if NBPFILTER > 0
 #include <net/bpf.h>
@@ -525,7 +528,7 @@ vio_attach(struct device *parent, struct device *self, void *aux)
 
        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_MRG_RXBUF | VIRTIO_NET_F_CSUM;
        /*
         * VIRTIO_F_RING_EVENT_IDX can be switched off by setting bit 2 in the
         * driver flags, see config(8)
@@ -589,6 +592,8 @@ vio_attach(struct device *parent, struct device *self, void *aux)
        ifp->if_start = vio_start;
        ifp->if_ioctl = vio_ioctl;
        ifp->if_capabilities = IFCAP_VLAN_MTU;
+       if (features & VIRTIO_NET_F_CSUM)
+               ifp->if_capabilities |= IFCAP_CSUM_TCPv4|IFCAP_CSUM_UDPv4;
        IFQ_SET_MAXLEN(&ifp->if_snd, vsc->sc_vqs[1].vq_num - 1);
        IFQ_SET_READY(&ifp->if_snd);
        ifmedia_init(&sc->sc_media, 0, vio_media_change, vio_media_status);
@@ -738,6 +743,34 @@ again:
                }
                if (r != 0)
                        panic("enqueue_prep for a tx buffer: %d", r);
+
+               hdr = &sc->sc_tx_hdrs[slot];
+               memset(hdr, 0, sc->sc_hdr_size);
+               if (m->m_pkthdr.csum_flags & (M_TCP_CSUM_OUT|M_UDP_CSUM_OUT)) {
+                       struct mbuf *mip;
+                       struct ip *ip;
+                       int ehdrlen = ETHER_HDR_LEN;
+                       int ipoff;
+#if NVLAN > 0
+                       struct ether_vlan_header *eh;
+
+                       eh = mtod(m, struct ether_vlan_header *);
+                       if (eh->evl_encap_proto == htons(ETHERTYPE_VLAN))
+                               ehdrlen += ETHER_VLAN_ENCAP_LEN;
+#endif
+
+                       if (m->m_pkthdr.csum_flags & M_TCP_CSUM_OUT)
+                               hdr->csum_offset = offsetof(struct tcphdr, th_sum);
+                       else
+                               hdr->csum_offset = offsetof(struct udphdr, uh_sum);
+
+                       mip = m_getptr(m, ehdrlen, &ipoff);
+                       KASSERT(mip != NULL && mip->m_len - ipoff >= sizeof(*ip));
+                       ip = (struct ip *)(mip->m_data + ipoff);
+                       hdr->csum_start = ehdrlen + (ip->ip_hl << 2);
+                       hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
+               }
+
                r = vio_encap(sc, slot, m);
                if (r != 0) {
                        virtio_enqueue_abort(vq, slot);
@@ -757,8 +790,6 @@ again:
                }
                IFQ_DEQUEUE(&ifp->if_snd, m);
 
-               hdr = &sc->sc_tx_hdrs[slot];
-               memset(hdr, 0, sc->sc_hdr_size);
                bus_dmamap_sync(vsc->sc_dmat, sc->sc_tx_dmamaps[slot], 0,
                    sc->sc_tx_dmamaps[slot]->dm_mapsize, BUS_DMASYNC_PREWRITE);
                VIO_DMAMEM_SYNC(vsc, sc, hdr, sc->sc_hdr_size,