From: bluhm <bluhm@openbsd.org>
Date: Sat, 13 May 2023 13:35:17 +0000 (+0000)
Subject: Instead of implementing IPv4 header checksum creation everywhere,
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=55055d619d36cc45f8c6891404c51cd405214e86;p=openbsd

Instead of implementing IPv4 header checksum creation everywhere,
introduce in_hdr_cksum_out().  It is used like in_proto_cksum_out().
OK claudio@
---

diff --git a/sys/net/if_bridge.c b/sys/net/if_bridge.c
index 463ca9cf96c..a5ad2281a70 100644
--- a/sys/net/if_bridge.c
+++ b/sys/net/if_bridge.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_bridge.c,v 1.366 2023/05/07 16:23:23 bluhm Exp $	*/
+/*	$OpenBSD: if_bridge.c,v 1.367 2023/05/13 13:35:17 bluhm Exp $	*/
 
 /*
  * Copyright (c) 1999, 2000 Jason L. Wright (jason@thought.net)
@@ -1735,15 +1735,8 @@ bridge_ip(struct ifnet *brifp, int dir, struct ifnet *ifp,
 			return (NULL);
 		if (m->m_len < sizeof(struct ip))
 			goto dropit;
+		in_hdr_cksum_out(m, ifp);
 		in_proto_cksum_out(m, ifp);
-		ip = mtod(m, struct ip *);
-		ip->ip_sum = 0;
-		if (0 && (ifp->if_capabilities & IFCAP_CSUM_IPv4))
-			m->m_pkthdr.csum_flags |= M_IPV4_CSUM_OUT;
-		else {
-			ipstat_inc(ips_outswcsum);
-			ip->ip_sum = in_cksum(m, hlen);
-		}
 
 #if NPF > 0
 		if (dir == BRIDGE_IN &&
@@ -1993,8 +1986,7 @@ bridge_send_icmp_err(struct ifnet *ifp,
 	ip->ip_off &= htons(IP_DF);
 	ip->ip_id = htons(ip_randomid());
 	ip->ip_ttl = MAXTTL;
-	ip->ip_sum = 0;
-	ip->ip_sum = in_cksum(m, hlen);
+	in_hdr_cksum_out(m, NULL);
 
 	/* Swap ethernet addresses */
 	bcopy(&eh->ether_dhost, &ether_tmp, sizeof(ether_tmp));
diff --git a/sys/net/if_gre.c b/sys/net/if_gre.c
index 6aebed6ee9d..cac48bb8f3d 100644
--- a/sys/net/if_gre.c
+++ b/sys/net/if_gre.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: if_gre.c,v 1.173 2023/04/13 02:19:05 jsg Exp $ */
+/*	$OpenBSD: if_gre.c,v 1.174 2023/05/13 13:35:17 bluhm Exp $ */
 /*	$NetBSD: if_gre.c,v 1.9 1999/10/25 19:18:11 drochner Exp $ */
 
 /*
@@ -3028,8 +3028,7 @@ gre_keepalive_send(void *arg)
 
 		ip = mtod(m, struct ip *);
 		ip->ip_id = htons(ip_randomid());
-		ip->ip_sum = 0;
-		ip->ip_sum = in_cksum(m, sizeof(*ip));
+		in_hdr_cksum_out(m, NULL);
 
 		proto = htons(ETHERTYPE_IP);
 		break;
diff --git a/sys/net/pf.c b/sys/net/pf.c
index ee979d9e8e5..7c395644c9b 100644
--- a/sys/net/pf.c
+++ b/sys/net/pf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pf.c,v 1.1178 2023/05/10 12:07:16 bluhm Exp $ */
+/*	$OpenBSD: pf.c,v 1.1179 2023/05/13 13:35:17 bluhm Exp $ */
 
 /*
  * Copyright (c) 2001 Daniel Hartmeier
@@ -2868,7 +2868,7 @@ pf_change_icmp_af(struct mbuf *m, int ipoff2, struct pf_pdesc *pd,
 			ip4->ip_p = pd2->proto;
 		ip4->ip_src = src->v4;
 		ip4->ip_dst = dst->v4;
-		ip4->ip_sum = in_cksum(n, ip4->ip_hl << 2);
+		in_hdr_cksum_out(n, NULL);
 		break;
 	case AF_INET6:
 		ip6 = mtod(n, struct ip6_hdr *);
@@ -6549,13 +6549,7 @@ pf_route(struct pf_pdesc *pd, struct pf_state *st)
 	}
 
 	if (ntohs(ip->ip_len) <= ifp->if_mtu) {
-		ip->ip_sum = 0;
-		if (ifp->if_capabilities & IFCAP_CSUM_IPv4)
-			m0->m_pkthdr.csum_flags |= M_IPV4_CSUM_OUT;
-		else {
-			ipstat_inc(ips_outswcsum);
-			ip->ip_sum = in_cksum(m0, ip->ip_hl << 2);
-		}
+		in_hdr_cksum_out(m0, ifp);
 		in_proto_cksum_out(m0, ifp);
 		ifp->if_output(ifp, m0, sintosa(dst), rt);
 		goto done;
diff --git a/sys/netinet/in.h b/sys/netinet/in.h
index 16dcdb24ca0..359be65f650 100644
--- a/sys/netinet/in.h
+++ b/sys/netinet/in.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: in.h,v 1.143 2023/05/10 12:07:16 bluhm Exp $	*/
+/*	$OpenBSD: in.h,v 1.144 2023/05/13 13:35:17 bluhm Exp $	*/
 /*	$NetBSD: in.h,v 1.20 1996/02/13 23:41:47 christos Exp $	*/
 
 /*
@@ -779,6 +779,7 @@ int	   in_broadcast(struct in_addr, u_int);
 int	   in_canforward(struct in_addr);
 int	   in_cksum(struct mbuf *, int);
 int	   in4_cksum(struct mbuf *, u_int8_t, int, int);
+void	   in_hdr_cksum_out(struct mbuf *, struct ifnet *);
 void	   in_proto_cksum_out(struct mbuf *, struct ifnet *);
 int	   in_ifcap_cksum(struct mbuf *, struct ifnet *, int);
 void	   in_ifdetach(struct ifnet *);
diff --git a/sys/netinet/ip_divert.c b/sys/netinet/ip_divert.c
index 77d7698076a..acb00eb853c 100644
--- a/sys/netinet/ip_divert.c
+++ b/sys/netinet/ip_divert.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: ip_divert.c,v 1.90 2023/04/04 10:12:03 bluhm Exp $ */
+/*      $OpenBSD: ip_divert.c,v 1.91 2023/05/13 13:35:17 bluhm Exp $ */
 
 /*
  * Copyright (c) 2009 Michele Marchetto <michele@openbsd.org>
@@ -157,8 +157,7 @@ divert_output(struct inpcb *inp, struct mbuf *m, struct mbuf *nam,
 		 * since the userspace application may have modified the packet
 		 * prior to reinjection.
 		 */
-		ip->ip_sum = 0;
-		ip->ip_sum = in_cksum(m, off);
+		in_hdr_cksum_out(m, NULL);
 		in_proto_cksum_out(m, NULL);
 
 		ifp = if_get(m->m_pkthdr.ph_ifidx);
@@ -190,8 +189,6 @@ divert_packet(struct mbuf *m, int dir, u_int16_t divert_port)
 	struct inpcb *inp = NULL;
 	struct socket *so;
 	struct sockaddr_in sin;
-	struct ip *ip;
-	int off;
 
 	divstat_inc(divs_ipackets);
 
@@ -239,11 +236,7 @@ divert_packet(struct mbuf *m, int dir, u_int16_t divert_port)
 		 * Calculate IP and protocol checksums for outbound packet 
 		 * diverted to userland.  pf rule diverts before cksum offload.
 		 */
-		ip = mtod(m, struct ip *);
-		off = ip->ip_hl << 2;
-
-		ip->ip_sum = 0;
-		ip->ip_sum = in_cksum(m, off);
+		in_hdr_cksum_out(m, NULL);
 		in_proto_cksum_out(m, NULL);
 	}
 
diff --git a/sys/netinet/ip_output.c b/sys/netinet/ip_output.c
index f5b1173a299..394da08ad9f 100644
--- a/sys/netinet/ip_output.c
+++ b/sys/netinet/ip_output.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ip_output.c,v 1.385 2023/05/10 12:07:16 bluhm Exp $	*/
+/*	$OpenBSD: ip_output.c,v 1.386 2023/05/13 13:35:17 bluhm Exp $	*/
 /*	$NetBSD: ip_output.c,v 1.28 1996/02/13 23:43:07 christos Exp $	*/
 
 /*
@@ -81,8 +81,7 @@ int ip_pcbopts(struct mbuf **, struct mbuf *);
 int ip_multicast_if(struct ip_mreqn *, u_int, unsigned int *);
 int ip_setmoptions(int, struct ip_moptions **, struct mbuf *, u_int);
 void ip_mloopback(struct ifnet *, struct mbuf *, struct sockaddr_in *);
-static __inline u_int16_t __attribute__((__unused__))
-    in_cksum_phdr(u_int32_t, u_int32_t, u_int32_t);
+static u_int16_t in_cksum_phdr(u_int32_t, u_int32_t, u_int32_t);
 void in_delayed_cksum(struct mbuf *);
 
 int ip_output_ipsec_lookup(struct mbuf *m, int hlen, struct inpcb *inp,
@@ -455,13 +454,7 @@ sendit:
 	 * If small enough for interface, can just send directly.
 	 */
 	if (ntohs(ip->ip_len) <= mtu) {
-		ip->ip_sum = 0;
-		if (in_ifcap_cksum(m, ifp, IFCAP_CSUM_IPv4))
-			m->m_pkthdr.csum_flags |= M_IPV4_CSUM_OUT;
-		else {
-			ipstat_inc(ips_outswcsum);
-			ip->ip_sum = in_cksum(m, hlen);
-		}
+		in_hdr_cksum_out(m, ifp);
 		in_proto_cksum_out(m, ifp);
 		error = ifp->if_output(ifp, m, sintosa(dst), ro->ro_rt);
 		goto done;
@@ -772,13 +765,7 @@ ip_fragment(struct mbuf *m0, struct mbuf_list *ml, struct ifnet *ifp,
 			goto bad;
 		}
 
-		mhip->ip_sum = 0;
-		if (in_ifcap_cksum(m, ifp, IFCAP_CSUM_IPv4))
-			m->m_pkthdr.csum_flags |= M_IPV4_CSUM_OUT;
-		else {
-			ipstat_inc(ips_outswcsum);
-			mhip->ip_sum = in_cksum(m, mhlen);
-		}
+		in_hdr_cksum_out(m, ifp);
 	}
 
 	/*
@@ -791,13 +778,7 @@ ip_fragment(struct mbuf *m0, struct mbuf_list *ml, struct ifnet *ifp,
 	}
 	ip->ip_len = htons(m0->m_pkthdr.len);
 
-	ip->ip_sum = 0;
-	if (in_ifcap_cksum(m0, ifp, IFCAP_CSUM_IPv4))
-		m0->m_pkthdr.csum_flags |= M_IPV4_CSUM_OUT;
-	else {
-		ipstat_inc(ips_outswcsum);
-		ip->ip_sum = in_cksum(m0, hlen);
-	}
+	in_hdr_cksum_out(m0, ifp);
 
 	ipstat_add(ips_ofragments, ml_len(ml));
 	return (0);
@@ -1806,7 +1787,6 @@ ip_freemoptions(struct ip_moptions *imo)
 void
 ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst)
 {
-	struct ip *ip;
 	struct mbuf *copym;
 
 	copym = m_dup_pkt(m, max_linkhdr, M_DONTWAIT);
@@ -1815,18 +1795,31 @@ ip_mloopback(struct ifnet *ifp, struct mbuf *m, struct sockaddr_in *dst)
 		 * We don't bother to fragment if the IP length is greater
 		 * than the interface's MTU.  Can this possibly matter?
 		 */
-		ip = mtod(copym, struct ip *);
-		ip->ip_sum = 0;
-		ip->ip_sum = in_cksum(copym, ip->ip_hl << 2);
+		in_hdr_cksum_out(copym, NULL);
 		if_input_local(ifp, copym, dst->sin_family);
 	}
 }
 
+void
+in_hdr_cksum_out(struct mbuf *m, struct ifnet *ifp)
+{
+	struct ip *ip = mtod(m, struct ip *);
+
+	ip->ip_sum = 0;
+	if (ifp && in_ifcap_cksum(m, ifp, IFCAP_CSUM_IPv4)) {
+		SET(m->m_pkthdr.csum_flags, M_IPV4_CSUM_OUT);
+	} else {
+		ipstat_inc(ips_outswcsum);
+		ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
+		CLR(m->m_pkthdr.csum_flags, M_IPV4_CSUM_OUT);
+	}
+}
+
 /*
  *	Compute significant parts of the IPv4 checksum pseudo-header
  *	for use in a delayed TCP/UDP checksum calculation.
  */
-static __inline u_int16_t __attribute__((__unused__))
+static u_int16_t
 in_cksum_phdr(u_int32_t src, u_int32_t dst, u_int32_t lenproto)
 {
 	u_int32_t sum;
diff --git a/sys/netinet/ipsec_input.c b/sys/netinet/ipsec_input.c
index 353466af1f3..5df9a4f9634 100644
--- a/sys/netinet/ipsec_input.c
+++ b/sys/netinet/ipsec_input.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: ipsec_input.c,v 1.203 2022/02/22 01:35:40 guenther Exp $	*/
+/*	$OpenBSD: ipsec_input.c,v 1.204 2023/05/13 13:35:17 bluhm Exp $	*/
 /*
  * The authors of this code are John Ioannidis (ji@tla.org),
  * Angelos D. Keromytis (kermit@csd.uch.gr) and
@@ -389,8 +389,7 @@ ipsec_common_input_cb(struct mbuf **mp, struct tdb *tdbp, int skip, int protoff)
 
 		ip = mtod(m, struct ip *);
 		ip->ip_len = htons(m->m_pkthdr.len);
-		ip->ip_sum = 0;
-		ip->ip_sum = in_cksum(m, ip->ip_hl << 2);
+		in_hdr_cksum_out(m, NULL);
 		prot = ip->ip_p;
 	}
 
diff --git a/sys/netinet/tcp_output.c b/sys/netinet/tcp_output.c
index 84adc729bf8..752b485ba27 100644
--- a/sys/netinet/tcp_output.c
+++ b/sys/netinet/tcp_output.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: tcp_output.c,v 1.136 2023/05/10 12:07:16 bluhm Exp $	*/
+/*	$OpenBSD: tcp_output.c,v 1.137 2023/05/13 13:35:18 bluhm Exp $	*/
 /*	$NetBSD: tcp_output.c,v 1.16 1997/06/03 16:17:09 kml Exp $	*/
 
 /*
@@ -1302,13 +1302,7 @@ tcp_chopper(struct mbuf *m0, struct mbuf_list *ml, struct ifnet *ifp,
 			*mhip = *ip;
 			mhip->ip_len = htons(hlen + len);
 			mhip->ip_id = htons(ip_randomid());
-			mhip->ip_sum = 0;
-			if (ifp && in_ifcap_cksum(m, ifp, IFCAP_CSUM_IPv4)) {
-				m->m_pkthdr.csum_flags |= M_IPV4_CSUM_OUT;
-			} else {
-				ipstat_inc(ips_outswcsum);
-				mhip->ip_sum = in_cksum(m, iphlen);
-			}
+			in_hdr_cksum_out(m, ifp);
 			in_proto_cksum_out(m, ifp);
 		}
 #ifdef INET6
@@ -1337,12 +1331,7 @@ tcp_chopper(struct mbuf *m0, struct mbuf_list *ml, struct ifnet *ifp,
 	if (ip) {
 		ip->ip_len = htons(m0->m_pkthdr.len);
 		ip->ip_sum = 0;
-		if (ifp && in_ifcap_cksum(m0, ifp, IFCAP_CSUM_IPv4)) {
-			m0->m_pkthdr.csum_flags |= M_IPV4_CSUM_OUT;
-		} else {
-			ipstat_inc(ips_outswcsum);
-			ip->ip_sum = in_cksum(m0, iphlen);
-		}
+		in_hdr_cksum_out(m0, ifp);
 		in_proto_cksum_out(m0, ifp);
 	}
 #ifdef INET6
diff --git a/sys/netmpls/mpls_input.c b/sys/netmpls/mpls_input.c
index a307499ff95..b25a9806a5f 100644
--- a/sys/netmpls/mpls_input.c
+++ b/sys/netmpls/mpls_input.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mpls_input.c,v 1.78 2021/07/22 11:07:17 mvs Exp $	*/
+/*	$OpenBSD: mpls_input.c,v 1.79 2023/05/13 13:35:18 bluhm Exp $	*/
 
 /*
  * Copyright (c) 2008 Claudio Jeker <claudio@openbsd.org>
@@ -416,8 +416,7 @@ mpls_do_error(struct mbuf *m, int type, int code, int destmtu)
 		/* stuff to fix up which is normally done in ip_output */
 		ip->ip_v = IPVERSION;
 		ip->ip_id = htons(ip_randomid());
-		ip->ip_sum = 0;
-		ip->ip_sum = in_cksum(m, sizeof(*ip));
+		in_hdr_cksum_out(m, NULL);
 
 		/* stolen from icmp_send() */
 		icp = (struct icmp *)(mtod(m, caddr_t) + sizeof(*ip));
diff --git a/sys/netmpls/mpls_output.c b/sys/netmpls/mpls_output.c
index 44c48eaefaa..ff7696cfcea 100644
--- a/sys/netmpls/mpls_output.c
+++ b/sys/netmpls/mpls_output.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: mpls_output.c,v 1.28 2019/09/03 10:39:08 jsg Exp $ */
+/* $OpenBSD: mpls_output.c,v 1.29 2023/05/13 13:35:18 bluhm Exp $ */
 
 /*
  * Copyright (c) 2008 Claudio Jeker <claudio@openbsd.org>
@@ -39,7 +39,6 @@
 #define MPLS_LABEL_GET(l)	((ntohl((l) & MPLS_LABEL_MASK)) >> MPLS_LABEL_OFFSET)
 #endif
 
-void		mpls_do_cksum(struct mbuf *);
 u_int8_t	mpls_getttl(struct mbuf *, sa_family_t);
 
 int
@@ -62,7 +61,9 @@ mpls_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
 	}
 
 	/* need to calculate checksums now if necessary */
-	mpls_do_cksum(m);
+	if (m->m_pkthdr.csum_flags & M_IPV4_CSUM_OUT)
+		in_hdr_cksum_out(m, NULL);
+	in_proto_cksum_out(m, NULL);
 
 	/* initialize sockaddr_mpls */
 	bzero(&sa_mpls, sizeof(sa_mpls));
@@ -143,22 +144,6 @@ bad:
 	return (error);
 }
 
-void
-mpls_do_cksum(struct mbuf *m)
-{
-	struct ip *ip;
-	u_int16_t hlen;
-
-	in_proto_cksum_out(m, NULL);
-
-	if (m->m_pkthdr.csum_flags & M_IPV4_CSUM_OUT) {
-		ip = mtod(m, struct ip *);
-		hlen = ip->ip_hl << 2;
-		ip->ip_sum = in_cksum(m, hlen);
-		m->m_pkthdr.csum_flags &= ~M_IPV4_CSUM_OUT;
-	}
-}
-
 u_int8_t
 mpls_getttl(struct mbuf *m, sa_family_t af)
 {