Ultrix-3.1/sys/net/ip_output.c
/**********************************************************************
* Copyright (c) Digital Equipment Corporation 1984, 1985, 1986. *
* All Rights Reserved. *
* Reference "/usr/src/COPYRIGHT" for applicable restrictions. *
**********************************************************************/
/*
* Copyright (c) 1982 Regents of the University of California.
* All rights reserved. The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*
* SCCSID: @(#)ip_output.c 3.0 4/21/86
* @(#)ip_output.c 3.0 (Berkeley) 4/21/86
*/
#include <sys/param.h>
#include <sys/mbuf.h>
#include <errno.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <net/if.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#ifdef vax
#include "../vax/mtpr.h"
#endif
ip_output(m, opt, ro, flags)
struct mbuf *m;
struct mbuf *opt;
struct route *ro;
int flags;
{
#ifndef pdp11
register struct ip *ip = mtod(m, struct ip *);
#else pdp11
register struct ip *ip;
#endif pdp11
register struct ifnet *ifp;
int len, hlen = sizeof (struct ip), off, error = 0;
struct route iproute;
struct sockaddr_in *dst;
if (opt) /* XXX */
(void) m_free(opt); /* XXX */
#ifdef pdp11
MAPSAVE();
ip = mtod(m, struct ip *);
#endif pdp11
/*
* Fill in IP header.
*/
if ((flags & IP_FORWARDING) == 0) {
ip->ip_v = IPVERSION;
ip->ip_off &= IP_DF;
ip->ip_id = htons(ip_id++);
ip->ip_hl = hlen >> 2;
}
#ifndef BSD
else
ip->ip_id = htons(ip->ip_id);
#endif BSD
/*
* Route packet.
*/
if (ro == 0) {
ro = &iproute;
bzero((caddr_t)ro, sizeof (*ro));
}
dst = (struct sockaddr_in *)&ro->ro_dst;
if (ro->ro_rt == 0) {
dst->sin_family = AF_INET;
dst->sin_addr = ip->ip_dst;
/*
* If routing to interface only,
* short circuit routing lookup.
*/
if (flags & IP_ROUTETOIF) {
struct in_ifaddr *ia;
ia = in_iaonnetof(in_netof(ip->ip_dst));
if (ia == 0) {
error = ENETUNREACH;
goto bad;
}
ifp = ia->ia_ifp;
goto gotif;
}
rtalloc(ro);
} else if ((ro->ro_rt->rt_flags & RTF_UP) == 0) {
/*
* The old route has gone away; try for a new one.
*/
rtfree(ro->ro_rt);
ro->ro_rt = NULL;
rtalloc(ro);
}
if (ro->ro_rt == 0 || (ifp = ro->ro_rt->rt_ifp) == 0) {
error = ENETUNREACH;
goto bad;
}
ro->ro_rt->rt_use++;
if (ro->ro_rt->rt_flags & (RTF_GATEWAY|RTF_HOST))
dst = (struct sockaddr_in *)&ro->ro_rt->rt_gateway;
gotif:
#ifndef notdef
/*
* If source address not specified yet, use address
* of outgoing interface.
*/
if (ip->ip_src.s_addr == INADDR_ANY) {
register struct in_ifaddr *ia;
for (ia = in_ifaddr; ia; ia = ia->ia_next)
if (ia->ia_ifp == ifp) {
ip->ip_src = IA_SIN(ia)->sin_addr;
break;
}
}
#endif
/*
* Look for broadcast address and
* and verify user is allowed to send
* such a packet.
*/
if (in_broadcast(dst->sin_addr)) {
if ((ifp->if_flags & IFF_BROADCAST) == 0) {
error = EADDRNOTAVAIL;
goto bad;
}
if ((flags & IP_ALLOWBROADCAST) == 0) {
error = EACCES;
goto bad;
}
/* don't allow broadcast messages to be fragmented */
if (ip->ip_len > ifp->if_mtu) {
error = EMSGSIZE;
goto bad;
}
}
/*
* If small enough for interface, can just send directly.
*/
if (ip->ip_len <= ifp->if_mtu) {
ip->ip_len = htons((u_short)ip->ip_len);
ip->ip_off = htons((u_short)ip->ip_off);
ip->ip_sum = 0;
ip->ip_sum = in_cksum(m, hlen);
error = (*ifp->if_output)(ifp, m, (struct sockaddr *)dst);
goto done;
}
/*
* Too large for interface; fragment if possible.
* Must be able to put at least 8 bytes per fragment.
*/
if (ip->ip_off & IP_DF) {
error = EMSGSIZE;
goto bad;
}
len = (ifp->if_mtu - hlen) &~ 7;
if (len < 8) {
error = EMSGSIZE;
goto bad;
}
/*
* Discard IP header from logical mbuf for m_copy's sake.
* Loop through length of segment, make a copy of each
* part and output.
*/
#ifdef pdp11
# define IP ((struct ip *)&ipcopy[0])
{
u_char ipcopy[64];
bcopy((caddr_t)ip, (caddr_t)ipcopy, hlen&0x3f);
#else
# define IP ip
#endif pdp11
m->m_len -= sizeof (struct ip);
m->m_off += sizeof (struct ip);
for (off = 0; off < IP->ip_len-hlen; off += len) {
struct mbuf *mh = m_get(M_DONTWAIT, MT_HEADER);
struct ip *mhip;
if (mh == 0) {
error = ENOBUFS;
goto bad;
}
mh->m_off = MMAXOFF - hlen;
mhip = mtod(mh, struct ip *);
*mhip = *IP;
if (hlen > sizeof (struct ip)) {
int olen = ip_optcopy(IP, mhip, off);
mh->m_len = sizeof (struct ip) + olen;
} else
mh->m_len = sizeof (struct ip);
mhip->ip_off = off >> 3;
if (IP->ip_off & IP_MF)
mhip->ip_off |= IP_MF;
if (off + len >= IP->ip_len-hlen)
len = mhip->ip_len = IP->ip_len - hlen - off;
else {
mhip->ip_len = len;
mhip->ip_off |= IP_MF;
}
mhip->ip_len += sizeof (struct ip);
mhip->ip_len = htons((u_short)mhip->ip_len);
mh->m_next = m_copy(m, off, len);
if (mh->m_next == 0) {
(void) m_free(mh);
error = ENOBUFS; /* ??? */
goto bad;
}
mhip->ip_off = htons((u_short)mhip->ip_off);
mhip->ip_sum = 0;
mhip->ip_sum = in_cksum(mh, hlen);
if (error = (*ifp->if_output)(ifp, mh, (struct sockaddr *)dst))
break;
}
#ifdef pdp11
}
#endif pdp11
bad:
m_freem(m);
done:
if (ro == &iproute && (flags & IP_ROUTETOIF) == 0 && ro->ro_rt)
RTFREE(ro->ro_rt);
#ifdef pdp11
MAPREST();
#endif pdp11
return (error);
}
/*
* Copy options from ip to jp.
* If off is 0 all options are copied
* otherwise copy selectively.
*/
static
ip_optcopy(ip, jp, off)
struct ip *ip, *jp;
int off;
{
register u_char *cp, *dp;
int opt, optlen, cnt;
cp = (u_char *)(ip + 1);
dp = (u_char *)(jp + 1);
cnt = (ip->ip_hl << 2) - sizeof (struct ip);
for (; cnt > 0; cnt -= optlen, cp += optlen) {
opt = cp[0];
if (opt == IPOPT_EOL)
break;
if (opt == IPOPT_NOP)
optlen = 1;
else
optlen = cp[1];
if (optlen > cnt) /* XXX */
optlen = cnt; /* XXX */
if (off == 0 || IPOPT_COPIED(opt)) {
bcopy((caddr_t)cp, (caddr_t)dp, (unsigned)optlen);
dp += optlen;
}
}
for (optlen = dp - (u_char *)(jp+1); optlen & 0x3; optlen++)
*dp++ = IPOPT_EOL;
return (optlen);
}