consolidate mbuf header parsing on device driver layer

with tweaks from mvs@, mpi@ and dlg@

ok mvs@, dlg@

4 files changed, 92 insertions, 88 deletions

diff --git a/sys/dev/pci/if_ix.c b/sys/dev/pci/if_ix.c
index b59ec28d9f1..21d48208954 100644
--- a/sys/dev/pci/if_ix.c
+++ b/sys/dev/pci/if_ix.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_ix.c,v 1.189 2022/09/02 14:08:09 jan Exp $	*/
+/*	$OpenBSD: if_ix.c,v 1.190 2023/01/24 22:35:46 jan Exp $	*/
 
 /******************************************************************************
 
@@ -2477,25 +2477,16 @@ static inline int
 ixgbe_csum_offload(struct mbuf *mp, uint32_t *vlan_macip_lens,
     uint32_t *type_tucmd_mlhl, uint32_t *olinfo_status)
 {
-	struct ether_header *eh = mtod(mp, struct ether_header *);
-	struct mbuf *m;
-	int hoff;
+	struct ether_extracted ext;
 	int offload = 0;
 	uint32_t iphlen;
-	uint8_t ipproto;
 
-	*vlan_macip_lens |= (sizeof(*eh) << IXGBE_ADVTXD_MACLEN_SHIFT);
+	ether_extract_headers(mp, &ext);
 
-	switch (ntohs(eh->ether_type)) {
-	case ETHERTYPE_IP: {
-		struct ip *ip;
+	*vlan_macip_lens |= (sizeof(*ext.eh) << IXGBE_ADVTXD_MACLEN_SHIFT);
 
-		m = m_getptr(mp, sizeof(*eh), &hoff);
-		KASSERT(m != NULL && m->m_len - hoff >= sizeof(*ip));
-		ip = (struct ip *)(mtod(m, caddr_t) + hoff);
-
-		iphlen = ip->ip_hl << 2;
-		ipproto = ip->ip_p;
+	if (ext.ip4) {
+		iphlen = ext.ip4->ip_hl << 2;
 
 		if (ISSET(mp->m_pkthdr.csum_flags, M_IPV4_CSUM_OUT)) {
 			*olinfo_status |= IXGBE_TXD_POPTS_IXSM << 8;
@@ -2503,46 +2494,30 @@ ixgbe_csum_offload(struct mbuf *mp, uint32_t *vlan_macip_lens,
 		}
 
 		*type_tucmd_mlhl |= IXGBE_ADVTXD_TUCMD_IPV4;
-		break;
-	}
-
 #ifdef INET6
-	case ETHERTYPE_IPV6: {
-		struct ip6_hdr *ip6;
-
-		m = m_getptr(mp, sizeof(*eh), &hoff);
-		KASSERT(m != NULL && m->m_len - hoff >= sizeof(*ip6));
-		ip6 = (struct ip6_hdr *)(mtod(m, caddr_t) + hoff);
-
-		iphlen = sizeof(*ip6);
-		ipproto = ip6->ip6_nxt;
+	} else if (ext.ip6) {
+		iphlen = sizeof(*ext.ip6);
 
 		*type_tucmd_mlhl |= IXGBE_ADVTXD_TUCMD_IPV6;
-		break;
-	}
 #endif
-
-	default:
+	} else {
 		return offload;
 	}
 
 	*vlan_macip_lens |= iphlen;
 
-	switch (ipproto) {
-	case IPPROTO_TCP:
+	if (ext.tcp) {
 		*type_tucmd_mlhl |= IXGBE_ADVTXD_TUCMD_L4T_TCP;
 		if (ISSET(mp->m_pkthdr.csum_flags, M_TCP_CSUM_OUT)) {
 			*olinfo_status |= IXGBE_TXD_POPTS_TXSM << 8;
 			offload = 1;
 		}
-		break;
-	case IPPROTO_UDP:
+	} else if (ext.udp) {
 		*type_tucmd_mlhl |= IXGBE_ADVTXD_TUCMD_L4T_UDP;
 		if (ISSET(mp->m_pkthdr.csum_flags, M_UDP_CSUM_OUT)) {
 			*olinfo_status |= IXGBE_TXD_POPTS_TXSM << 8;
 			offload = 1;
 		}
-		break;
 	}
 
 	return offload;
diff --git a/sys/dev/pci/if_ixl.c b/sys/dev/pci/if_ixl.c
index 8af9473bc25..8d2720765bd 100644
--- a/sys/dev/pci/if_ixl.c
+++ b/sys/dev/pci/if_ixl.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_ixl.c,v 1.84 2022/08/05 13:57:16 bluhm Exp $ */
+/*	$OpenBSD: if_ixl.c,v 1.85 2023/01/24 22:35:46 jan Exp $ */
 
 /*
  * Copyright (c) 2013-2015, Intel Corporation
@@ -2784,10 +2784,8 @@ ixl_load_mbuf(bus_dma_tag_t dmat, bus_dmamap_t map, struct mbuf *m)
 static uint64_t
 ixl_tx_setup_offload(struct mbuf *m0)
 {
-	struct mbuf *m;
-	int hoff;
+	struct ether_extracted ext;
 	uint64_t hlen;
-	uint8_t ipproto;
 	uint64_t offload = 0;
 
 	if (ISSET(m0->m_flags, M_VLANTAG)) {
@@ -2800,39 +2798,21 @@ ixl_tx_setup_offload(struct mbuf *m0)
 	    M_IPV4_CSUM_OUT|M_TCP_CSUM_OUT|M_UDP_CSUM_OUT))
 		return (offload);
 
-	switch (ntohs(mtod(m0, struct ether_header *)->ether_type)) {
-	case ETHERTYPE_IP: {
-		struct ip *ip;
-
-		m = m_getptr(m0, ETHER_HDR_LEN, &hoff);
-		KASSERT(m != NULL && m->m_len - hoff >= sizeof(*ip));
-		ip = (struct ip *)(mtod(m, caddr_t) + hoff);
+	ether_extract_headers(m0, &ext);
 
+	if (ext.ip4) {
 		offload |= ISSET(m0->m_pkthdr.csum_flags, M_IPV4_CSUM_OUT) ?
 		    IXL_TX_DESC_CMD_IIPT_IPV4_CSUM :
 		    IXL_TX_DESC_CMD_IIPT_IPV4;
  
-		hlen = ip->ip_hl << 2;
-		ipproto = ip->ip_p;
-		break;
-	}
-
+		hlen = ext.ip4->ip_hl << 2;
 #ifdef INET6
-	case ETHERTYPE_IPV6: {
-		struct ip6_hdr *ip6;
-
-		m = m_getptr(m0, ETHER_HDR_LEN, &hoff);
-		KASSERT(m != NULL && m->m_len - hoff >= sizeof(*ip6));
-		ip6 = (struct ip6_hdr *)(mtod(m, caddr_t) + hoff);
- 
+	} else if (ext.ip6) {
 		offload |= IXL_TX_DESC_CMD_IIPT_IPV6;
 
-		hlen = sizeof(*ip6);
-		ipproto = ip6->ip6_nxt;
-		break;
-	}
+		hlen = sizeof(*ext.ip6);
 #endif
-	default:
+	} else {
 		panic("CSUM_OUT set for non-IP packet");
 		/* NOTREACHED */
 	}
@@ -2840,30 +2820,12 @@ ixl_tx_setup_offload(struct mbuf *m0)
 	offload |= (ETHER_HDR_LEN >> 1) << IXL_TX_DESC_MACLEN_SHIFT;
 	offload |= (hlen >> 2) << IXL_TX_DESC_IPLEN_SHIFT;
 
-	switch (ipproto) {
-	case IPPROTO_TCP: {
-		struct tcphdr *th;
-
-		if (!ISSET(m0->m_pkthdr.csum_flags, M_TCP_CSUM_OUT))
-			break;
-
-		m = m_getptr(m, hoff + hlen, &hoff);
-		KASSERT(m != NULL && m->m_len - hoff >= sizeof(*th));
-		th = (struct tcphdr *)(mtod(m, caddr_t) + hoff);
- 
+	if (ext.tcp && ISSET(m0->m_pkthdr.csum_flags, M_TCP_CSUM_OUT)) {
 		offload |= IXL_TX_DESC_CMD_L4T_EOFT_TCP;
-		offload |= (uint64_t)th->th_off << IXL_TX_DESC_L4LEN_SHIFT;
-		break;
-	}
-
-	case IPPROTO_UDP:
-		if (!ISSET(m0->m_pkthdr.csum_flags, M_UDP_CSUM_OUT))
-			break;
- 
+		offload |= (uint64_t)ext.tcp->th_off << IXL_TX_DESC_L4LEN_SHIFT;
+	} else if (ext.udp && ISSET(m0->m_pkthdr.csum_flags, M_UDP_CSUM_OUT)) {
 		offload |= IXL_TX_DESC_CMD_L4T_EOFT_UDP;
-		offload |= (sizeof(struct udphdr) >> 2) <<
-		    IXL_TX_DESC_L4LEN_SHIFT;
-		break;
+		offload |= (sizeof(*ext.udp) >> 2) << IXL_TX_DESC_L4LEN_SHIFT;
 	}
 
 	return (offload);
diff --git a/sys/net/if_ethersubr.c b/sys/net/if_ethersubr.c
index 3fb702c453f..9c28a1c172e 100644
--- a/sys/net/if_ethersubr.c
+++ b/sys/net/if_ethersubr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_ethersubr.c,v 1.284 2022/06/29 09:08:07 mvs Exp $	*/
+/*	$OpenBSD: if_ethersubr.c,v 1.285 2023/01/24 22:35:47 jan Exp $	*/
 /*	$NetBSD: if_ethersubr.c,v 1.19 1996/05/07 02:40:30 thorpej Exp $	*/
 
 /*
@@ -98,6 +98,10 @@ didn't get a copy, you may request one from <license@ipv6.nrl.navy.mil>.
 #include <netinet/in.h>
 #include <netinet/if_ether.h>
 #include <netinet/ip_ipsp.h>
+#include <netinet/ip.h>
+#include <netinet/ip6.h>
+#include <netinet/tcp.h>
+#include <netinet/udp.h>
 
 #if NBPFILTER > 0
 #include <net/bpf.h>
@@ -1034,3 +1038,56 @@ ether_e64_to_addr(struct ether_addr *ea, uint64_t e64)
 		e64 >>= 8;
 	} while (i > 0);
 }
+
+/* Parse different TCP/IP protocol headers for a quick view inside an mbuf. */
+void
+ether_extract_headers(struct mbuf *mp, struct ether_extracted *ext)
+{
+	struct mbuf	*m;
+	uint64_t	 hlen;
+	int		 hoff;
+	uint8_t		 ipproto;
+
+	/* Return NULL if header was not recognized. */
+	memset(ext, 0, sizeof *ext);
+
+	ext->eh = mtod(mp, struct ether_header *);
+	switch (ntohs(ext->eh->ether_type)) {
+	case ETHERTYPE_IP:
+		m = m_getptr(mp, sizeof(*ext->eh), &hoff);
+		KASSERT(m != NULL && m->m_len - hoff >= sizeof(*ext->ip4));
+		ext->ip4 = (struct ip *)(mtod(m, caddr_t) + hoff);
+
+		hlen = ext->ip4->ip_hl << 2;
+		ipproto = ext->ip4->ip_p;
+
+		break;
+#ifdef INET6
+	case ETHERTYPE_IPV6:
+		m = m_getptr(mp, sizeof(*ext->eh), &hoff);
+		KASSERT(m != NULL && m->m_len - hoff >= sizeof(*ext->ip6));
+		ext->ip6 = (struct ip6_hdr *)(mtod(m, caddr_t) + hoff);
+
+		hlen = sizeof(*ext->ip6);
+		ipproto = ext->ip6->ip6_nxt;
+
+		break;
+#endif
+	default:
+		return;
+	}
+
+	switch (ipproto) {
+	case IPPROTO_TCP:
+		m = m_getptr(m, hoff + hlen, &hoff);
+		KASSERT(m != NULL && m->m_len - hoff >= sizeof(*ext->tcp));
+		ext->tcp = (struct tcphdr *)(mtod(m, caddr_t) + hoff);
+		break;
+
+	case IPPROTO_UDP:
+		m = m_getptr(m, hoff + hlen, &hoff);
+		KASSERT(m != NULL && m->m_len - hoff >= sizeof(*ext->udp));
+		ext->udp = (struct udphdr *)(mtod(m, caddr_t) + hoff);
+		break;
+	}
+}
diff --git a/sys/netinet/if_ether.h b/sys/netinet/if_ether.h
index 8b66114f9a5..a90bacbf5cf 100644
--- a/sys/netinet/if_ether.h
+++ b/sys/netinet/if_ether.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_ether.h,v 1.84 2022/12/27 20:13:03 patrick Exp $	*/
+/*	$OpenBSD: if_ether.h,v 1.85 2023/01/24 22:35:47 jan Exp $	*/
 /*	$NetBSD: if_ether.h,v 1.22 1996/05/11 13:00:00 mycroft Exp $	*/
 
 /*
@@ -297,6 +297,16 @@ const struct ether_brport *
 uint64_t	ether_addr_to_e64(const struct ether_addr *);
 void		ether_e64_to_addr(struct ether_addr *, uint64_t);
 
+struct ether_extracted {
+	struct ether_header	*eh;
+	struct ip		*ip4;
+	struct ip6_hdr		*ip6;
+	struct tcphdr		*tcp;
+	struct udphdr		*udp;
+};
+
+void ether_extract_headers(struct mbuf *, struct ether_extracted *);
+
 /*
  * Ethernet multicast address structure.  There is one of these for each
  * multicast address or range of multicast addresses that we are supposed