From: henning <henning@openbsd.org>
Date: Fri, 18 Apr 2014 15:13:01 +0000 (+0000)
Subject: pf_send_tcp: ask the stack to do the cksum instead of doing it manually
X-Git-Url: http://artulab.com/gitweb/?a=commitdiff_plain;h=674c6722fd99bcab1a0b18f93e169f91bf0f521f;p=openbsd

pf_send_tcp: ask the stack to do the cksum instead of doing it manually
ok benno lteo naddy (back in january)
---

diff --git a/sys/net/pf.c b/sys/net/pf.c
index c2a1fa554dc..662957d30de 100644
--- a/sys/net/pf.c
+++ b/sys/net/pf.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pf.c,v 1.871 2014/04/14 09:06:42 mpi Exp $ */
+/*	$OpenBSD: pf.c,v 1.872 2014/04/18 15:13:01 henning Exp $ */
 
 /*
  * Copyright (c) 2001 Daniel Hartmeier
@@ -2377,15 +2377,21 @@ pf_send_tcp(const struct pf_rule *r, sa_family_t af,
 	m->m_data += max_linkhdr;
 	m->m_pkthdr.len = m->m_len = len;
 	m->m_pkthdr.rcvif = NULL;
+	m->m_pkthdr.csum_flags |= M_TCP_CSUM_OUT;
 	bzero(m->m_data, len);
 	switch (af) {
 #ifdef INET
 	case AF_INET:
 		h = mtod(m, struct ip *);
-
-		/* IP header fields included in the TCP checksum */
 		h->ip_p = IPPROTO_TCP;
 		h->ip_len = htons(tlen);
+		h->ip_v = 4;
+		h->ip_hl = sizeof(*h) >> 2;
+		h->ip_tos = IPTOS_LOWDELAY;
+		h->ip_len = htons(len);
+		h->ip_off = htons(ip_mtudisc ? IP_DF : 0);
+		h->ip_ttl = ttl ? ttl : ip_defttl;
+		h->ip_sum = 0;
 		h->ip_src.s_addr = saddr->v4.s_addr;
 		h->ip_dst.s_addr = daddr->v4.s_addr;
 
@@ -2395,10 +2401,10 @@ pf_send_tcp(const struct pf_rule *r, sa_family_t af,
 #ifdef INET6
 	case AF_INET6:
 		h6 = mtod(m, struct ip6_hdr *);
-
-		/* IP header fields included in the TCP checksum */
 		h6->ip6_nxt = IPPROTO_TCP;
 		h6->ip6_plen = htons(tlen);
+		h6->ip6_vfc |= IPV6_VERSION;
+		h6->ip6_hlim = IPV6_DEFHLIM;
 		memcpy(&h6->ip6_src, &saddr->v6, sizeof(struct in6_addr));
 		memcpy(&h6->ip6_dst, &daddr->v6, sizeof(struct in6_addr));
 
@@ -2427,17 +2433,6 @@ pf_send_tcp(const struct pf_rule *r, sa_family_t af,
 	switch (af) {
 #ifdef INET
 	case AF_INET:
-		/* TCP checksum */
-		th->th_sum = in_cksum(m, len);
-
-		/* Finish the IP header */
-		h->ip_v = 4;
-		h->ip_hl = sizeof(*h) >> 2;
-		h->ip_tos = IPTOS_LOWDELAY;
-		h->ip_len = htons(len);
-		h->ip_off = htons(ip_mtudisc ? IP_DF : 0);
-		h->ip_ttl = ttl ? ttl : ip_defttl;
-		h->ip_sum = 0;
 		if (eh == NULL) {
 			ip_output(m, (void *)NULL, (void *)NULL, 0,
 			    (void *)NULL, (void *)NULL);
@@ -2464,13 +2459,6 @@ pf_send_tcp(const struct pf_rule *r, sa_family_t af,
 #endif /* INET */
 #ifdef INET6
 	case AF_INET6:
-		/* TCP checksum */
-		th->th_sum = in6_cksum(m, IPPROTO_TCP,
-		    sizeof(struct ip6_hdr), tlen);
-
-		h6->ip6_vfc |= IPV6_VERSION;
-		h6->ip6_hlim = IPV6_DEFHLIM;
-
 		ip6_output(m, NULL, NULL, 0, NULL, NULL, NULL);
 		break;
 #endif /* INET6 */