tcp_respond: let the stack worry about the cksum instead of doing it

manually, ok naddy (in january)

diff --git a/sys/netinet/tcp_subr.c b/sys/netinet/tcp_subr.c
index 4ab283c..1c22f6e 100644 (file)
--- a/sys/netinet/tcp_subr.c
+++ b/sys/netinet/tcp_subr.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: tcp_subr.c,v 1.126 2014/04/14 09:06:42 mpi Exp $      */
+/*     $OpenBSD: tcp_subr.c,v 1.127 2014/04/18 15:14:25 henning Exp $  */
 /*     $NetBSD: tcp_subr.c,v 1.22 1996/02/13 23:44:00 christos Exp $   */
 
 /*
@@ -319,7 +319,6 @@ tcp_respond(struct tcpcb *tp, caddr_t template, struct tcphdr *th0,
        struct route *ro = 0;
        struct tcphdr *th;
        struct ip *ip;
-       struct ipovly *ih;
 #ifdef INET6
        struct ip6_hdr *ip6;
 #endif
@@ -385,6 +384,7 @@ tcp_respond(struct tcpcb *tp, caddr_t template, struct tcphdr *th0,
        m->m_len = tlen;
        m->m_pkthdr.len = tlen;
        m->m_pkthdr.rcvif = (struct ifnet *) 0;
+       m->m_pkthdr.csum_flags |= M_TCP_CSUM_OUT;
        th->th_seq = htonl(seq);
        th->th_ack = htonl(ack);
        th->th_x2 = 0;
@@ -410,9 +410,6 @@ tcp_respond(struct tcpcb *tp, caddr_t template, struct tcphdr *th0,
                ip6->ip6_nxt  = IPPROTO_TCP;
                ip6->ip6_hlim = in6_selecthlim(tp ? tp->t_inpcb : NULL, NULL);  /*XXX*/
                ip6->ip6_plen = tlen - sizeof(struct ip6_hdr);
-               th->th_sum = 0;
-               th->th_sum = in6_cksum(m, IPPROTO_TCP,
-                  sizeof(struct ip6_hdr), ip6->ip6_plen);
                HTONS(ip6->ip6_plen);
                ip6_output(m, tp ? tp->t_inpcb->inp_outputopts6 : NULL,
                    (struct route_in6 *)ro, 0, NULL, NULL,
@@ -420,19 +417,9 @@ tcp_respond(struct tcpcb *tp, caddr_t template, struct tcphdr *th0,
                break;
 #endif /* INET6 */
        case AF_INET:
-               ih = (struct ipovly *)ip;
-               bzero(ih->ih_x1, sizeof ih->ih_x1);
-               ih->ih_len = htons((u_short)tlen - sizeof(struct ip));
-
-               /*
-                * There's no point deferring to hardware checksum processing
-                * here, as we only send a minimal TCP packet whose checksum
-                * we need to compute in any case.
-                */
-               th->th_sum = 0;
-               th->th_sum = in_cksum(m, tlen);
                ip->ip_len = htons(tlen);
                ip->ip_ttl = ip_defttl;
+               ip->ip_tos = 0;
                ip_output(m, (void *)NULL, ro, ip_mtudisc ? IP_MTUDISC : 0,
                        (void *)NULL, tp ? tp->t_inpcb : (void *)NULL);
        }