vio(4): simplify mbuf parsing with ether_extract_headers()

ok sf@

diff --git a/sys/dev/pv/if_vio.c b/sys/dev/pv/if_vio.c
index 5c9a05f..787b6a5 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 1.27 2023/12/09 10:36:05 jan Exp $ */
+/*     $OpenBSD: if_vio.c,v 1.28 2023/12/11 09:40:42 jan Exp $ */
 
 /*
  * Copyright (c) 2012 Stefan Fritsch, Alexander Fiveg.
@@ -749,27 +749,22 @@ again:
                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;
+                       struct ether_extracted ext;
 
-                       eh = mtod(m, struct ether_vlan_header *);
-                       if (eh->evl_encap_proto == htons(ETHERTYPE_VLAN))
-                               ehdrlen += ETHER_VLAN_ENCAP_LEN;
+                       ether_extract_headers(m, &ext);
+                       hdr->csum_start = sizeof(*ext.eh);
+#if NVLAN > 0
+                       if (ext.evh)
+                               hdr->csum_start = sizeof(*ext.evh);
 #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);
+                       if (ext.ip4)
+                               hdr->csum_start += ext.ip4->ip_hl << 2;
+
                        hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
                }