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Fix a problem pointed out by Charles Hannum; DF wasn't being set in

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SYN,ACK packets during Path MTU Discovery.  Fix tcp_respond() to do the
appropriate route lookup and set DF as appropriate.

Also, fixup similar code in tcp_output() to relookup the route if it
is down.
This commit is contained in:
thorpej 1999-01-20 03:39:54 +00:00
parent e612d0da5f
commit a43786143f
2 changed files with 83 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
sys/netinet/tcp_output.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: tcp_output.c,v 1.46 1998/12/16 00:33:14 thorpej Exp $ */
/* $NetBSD: tcp_output.c,v 1.47 1999/01/20 03:39:54 thorpej Exp $ */
/*-
* Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
@ -170,8 +170,11 @@ int
tcp_output(tp)
register struct tcpcb *tp;
{
register struct socket *so = tp->t_inpcb->inp_socket;
register long len, win;
struct socket *so = tp->t_inpcb->inp_socket;
struct route *ro = &tp->t_inpcb->inp_route;
struct rtentry *rt;
struct sockaddr_in *dst;
long len, win;
int off, flags, error;
register struct mbuf *m;
register struct tcpiphdr *ti;
@ -662,25 +665,46 @@ send:
* the template, but need a way to checksum without them.
*/
m->m_pkthdr.len = hdrlen + len;
{
struct rtentry *rt;
((struct ip *)ti)->ip_len = m->m_pkthdr.len;
((struct ip *)ti)->ip_ttl = tp->t_inpcb->inp_ip.ip_ttl; /* XXX */
((struct ip *)ti)->ip_tos = tp->t_inpcb->inp_ip.ip_tos; /* XXX */
if (ip_mtudisc && (rt = in_pcbrtentry(tp->t_inpcb)) != 0 &&
(rt->rt_rmx.rmx_locks & RTV_MTU) == 0)
/*
* If we're doing Path MTU discovery, we need to set DF unless
* the route's MTU is locked. If we lack a route, we need to
* look it up now.
*
* ip_output() could do this for us, but it's convenient to just
* do it here unconditionally.
*/
if ((rt = ro->ro_rt) == NULL || (rt->rt_flags & RTF_UP) == 0) {
if (ro->ro_rt != NULL) {
RTFREE(ro->ro_rt);
ro->ro_rt = NULL;
}
dst = satosin(&ro->ro_dst);
dst->sin_family = AF_INET;
dst->sin_len = sizeof(*dst);
dst->sin_addr = tp->t_inpcb->inp_faddr;
rtalloc(ro);
if ((rt = ro->ro_rt) == NULL) {
m_freem(m);
ipstat.ips_noroute++;
error = EHOSTUNREACH;
goto out;
}
}
if (ip_mtudisc != 0 && (rt->rt_rmx.rmx_locks & RTV_MTU) == 0)
((struct ip *)ti)->ip_off |= IP_DF;
#if BSD >= 43
error = ip_output(m, tp->t_inpcb->inp_options, &tp->t_inpcb->inp_route,
error = ip_output(m, tp->t_inpcb->inp_options, ro,
so->so_options & SO_DONTROUTE, 0);
#else
error = ip_output(m, (struct mbuf *)0, &tp->t_inpcb->inp_route,
error = ip_output(m, (struct mbuf *)0, ro,
so->so_options & SO_DONTROUTE);
#endif
}
if (error) {
out:
if (error == ENOBUFS) {

55
sys/netinet/tcp_subr.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: tcp_subr.c,v 1.63 1998/12/18 21:38:03 thorpej Exp $ */
/* $NetBSD: tcp_subr.c,v 1.64 1999/01/20 03:39:54 thorpej Exp $ */
/*-
* Copyright (c) 1997, 1998 The NetBSD Foundation, Inc.
@ -212,14 +212,22 @@ tcp_respond(tp, ti, m, ack, seq, flags)
tcp_seq ack, seq;
int flags;
{
register int tlen;
int win = 0;
struct route *ro = 0;
struct route iproute, *ro;
struct rtentry *rt;
struct sockaddr_in *dst;
int error, tlen, win = 0;
if (tp) {
if (tp != NULL) {
if ((flags & TH_RST) == 0)
win = sbspace(&tp->t_inpcb->inp_socket->so_rcv);
ro = &tp->t_inpcb->inp_route;
#ifdef DIAGNOSTIC
if (!in_hosteq(ti->ti_dst, tp->t_inpcb->inp_faddr))
panic("tcp_respond: ti_dst != inp_faddr");
#endif
} else {
ro = &iproute;
bzero(ro, sizeof(*ro));
}
if (m == 0) {
m = m_gethdr(M_DONTWAIT, MT_HEADER);
@ -270,7 +278,42 @@ tcp_respond(tp, ti, m, ack, seq, flags)
ti->ti_sum = in_cksum(m, tlen);
((struct ip *)ti)->ip_len = tlen;
((struct ip *)ti)->ip_ttl = ip_defttl;
return ip_output(m, NULL, ro, 0, NULL);
/*
* If we're doing Path MTU discovery, we need to set DF unless
* the route's MTU is locked. If we lack a route, we need to
* look it up now.
*
* ip_output() could do this for us, but it's convenient to just
* do it here unconditionally.
*/
if ((rt = ro->ro_rt) == NULL || (rt->rt_flags & RTF_UP) == 0) {
if (ro->ro_rt != NULL) {
RTFREE(ro->ro_rt);
ro->ro_rt = NULL;
}
dst = satosin(&ro->ro_dst);
dst->sin_family = AF_INET;
dst->sin_len = sizeof(*dst);
dst->sin_addr = ti->ti_dst;
rtalloc(ro);
if ((rt = ro->ro_rt) == NULL) {
m_freem(m);
ipstat.ips_noroute++;
return (EHOSTUNREACH);
}
}
if (ip_mtudisc != 0 && (rt->rt_rmx.rmx_locks & RTV_MTU) == 0)
((struct ip *)ti)->ip_off |= IP_DF;
error = ip_output(m, NULL, ro, 0, NULL);
if (ro == &iproute) {
RTFREE(ro->ro_rt);
ro->ro_rt = NULL;
}
return (error);
}
/*