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Only transmit fragments if the send queue of interface can actually hold

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all of the fragments.  Use the mtu of route in preference of the MTU of the
interface when doing fragmentation decisions.  (ie. Fragment to the path
mtu if it is available).
This commit is contained in:
matt 1998-04-28 15:26:00 +00:00
parent d00ec01b00
commit 5b43c678b7
1 changed files with 23 additions and 6 deletions
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29
sys/netinet/ip_output.c
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@ -1,4 +1,4 @@
/* $NetBSD: ip_output.c,v 1.47 1998/03/24 03:10:02 kml Exp $ */
/* $NetBSD: ip_output.c,v 1.48 1998/04/28 15:26:00 matt Exp $ */
/*-
* Copyright (c) 1998 The NetBSD Foundation, Inc.
@ -131,6 +131,7 @@ ip_output(m0, va_alist)
struct route *ro;
int flags;
int *mtu_p;
int mtu;
struct ip_moptions *imo;
va_list ap;
#ifdef PFIL_HOOKS
@ -205,6 +206,7 @@ ip_output(m0, va_alist)
goto bad;
}
ifp = ia->ia_ifp;
mtu = ifp->if_mtu;
ip->ip_ttl = 1;
} else {
if (ro->ro_rt == 0)
@ -216,6 +218,8 @@ ip_output(m0, va_alist)
}
ia = ifatoia(ro->ro_rt->rt_ifa);
ifp = ro->ro_rt->rt_ifp;
if ((mtu = ro->ro_rt->rt_rmx.rmx_mtu) == 0)
mtu = ifp->if_mtu;
ro->ro_rt->rt_use++;
if (ro->ro_rt->rt_flags & RTF_GATEWAY)
dst = satosin(ro->ro_rt->rt_gateway);
@ -235,8 +239,10 @@ ip_output(m0, va_alist)
*/
if (imo != NULL) {
ip->ip_ttl = imo->imo_multicast_ttl;
if (imo->imo_multicast_ifp != NULL)
if (imo->imo_multicast_ifp != NULL) {
ifp = imo->imo_multicast_ifp;
mtu = ifp->if_mtu;
}
} else
ip->ip_ttl = IP_DEFAULT_MULTICAST_TTL;
/*
@ -355,9 +361,9 @@ ip_output(m0, va_alist)
#endif /* PFIL_HOOKS */
sendit:
/*
* If small enough for interface, can just send directly.
* If small enough for mtu of path, can just send directly.
*/
if ((u_int16_t)ip->ip_len <= ifp->if_mtu) {
if ((u_int16_t)ip->ip_len <= mtu) {
ip->ip_len = htons((u_int16_t)ip->ip_len);
ip->ip_off = htons((u_int16_t)ip->ip_off);
ip->ip_sum = 0;
@ -371,12 +377,12 @@ sendit:
*/
if (ip->ip_off & IP_DF) {
if (flags & IP_RETURNMTU)
*mtu_p = ifp->if_mtu;
*mtu_p = mtu;
error = EMSGSIZE;
ipstat.ips_cantfrag++;
goto bad;
}
len = (ifp->if_mtu - hlen) &~ 7;
len = (mtu - hlen) &~ 7;
if (len < 8) {
error = EMSGSIZE;
goto bad;
@ -385,6 +391,8 @@ sendit:
{
int mhlen, firstlen = len;
struct mbuf **mnext = &m->m_nextpkt;
int fragments = 0;
int s;
/*
* Loop through length of segment after first fragment,
@ -429,6 +437,7 @@ sendit:
mhip->ip_sum = 0;
mhip->ip_sum = in_cksum(m, mhlen);
ipstat.ips_ofragments++;
fragments++;
}
/*
* Update first fragment by trimming what's been copied out
@ -442,6 +451,14 @@ sendit:
ip->ip_sum = 0;
ip->ip_sum = in_cksum(m, hlen);
sendorfree:
/*
* If there is no room for all the fragments, don't queue
* any of them.
*/
s = splimp();
if (ifp->if_snd.ifq_maxlen - ifp->if_snd.ifq_len < fragments)
error = ENOBUFS;
splx(s);
for (m = m0; m; m = m0) {
m0 = m->m_nextpkt;
m->m_nextpkt = 0;