2.11BSD/sys/netns/ns_input.c
/*
* Copyright (c) 1984, 1985, 1986, 1987 Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms are permitted
* provided that this notice is preserved and that due credit is given
* to the University of California at Berkeley. The name of the University
* may not be used to endorse or promote products derived from this
* software without specific prior written permission. This software
* is provided ``as is'' without express or implied warranty.
*
* @(#)ns_input.c 7.2 (Berkeley) 1/20/88
*/
#include "param.h"
#ifdef NS
#include "systm.h"
#include "mbuf.h"
#include "domain.h"
#include "protosw.h"
#include "socket.h"
#include "socketvar.h"
#include "errno.h"
#include "time.h"
#include "kernel.h"
#include "../net/if.h"
#include "../net/route.h"
#include "../net/raw_cb.h"
#include "ns.h"
#include "ns_if.h"
#include "ns_pcb.h"
#include "idp.h"
#include "idp_var.h"
#include "ns_error.h"
/*
* NS initialization.
*/
union ns_host ns_thishost;
union ns_host ns_zerohost;
union ns_host ns_broadhost;
union ns_net ns_zeronet;
union ns_net ns_broadnet;
static u_short allones[] = {-1, -1, -1};
struct nspcb nspcb;
struct nspcb nsrawpcb;
struct ifqueue nsintrq;
int nsqmaxlen = IFQ_MAXLEN;
int idpcksum = 1;
long ns_pexseq;
ns_init()
{
extern struct timeval time;
ns_broadhost = * (union ns_host *) allones;
ns_broadnet = * (union ns_net *) allones;
nspcb.nsp_next = nspcb.nsp_prev = &nspcb;
nsrawpcb.nsp_next = nsrawpcb.nsp_prev = &nsrawpcb;
nsintrq.ifq_maxlen = nsqmaxlen;
ns_pexseq = time.tv_usec;
}
/*
* Idp input routine. Pass to next level.
*/
int nsintr_getpck = 0;
int nsintr_swtch = 0;
nsintr()
{
register struct idp *idp;
register struct mbuf *m;
register struct nspcb *nsp;
struct ifnet *ifp;
struct mbuf *m0;
register int i;
int len, s, error;
char oddpacketp;
next:
/*
* Get next datagram off input queue and get IDP header
* in first mbuf.
*/
s = splimp();
IF_DEQUEUEIF(&nsintrq, m, ifp);
splx(s);
nsintr_getpck++;
if (m == 0)
return;
if ((m->m_off > MMAXOFF || m->m_len < sizeof (struct idp)) &&
(m = m_pullup(m, sizeof (struct idp))) == 0) {
idpstat.idps_toosmall++;
goto next;
}
/*
* Give any raw listeners a crack at the packet
*/
for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) {
struct mbuf *m1 = m_copy(m, 0, (int)M_COPYALL);
if (m1) idp_input(m1, nsp, ifp);
}
idp = mtod(m, struct idp *);
len = ntohs(idp->idp_len);
if (oddpacketp = len & 1) {
len++; /* If this packet is of odd length,
preserve garbage byte for checksum */
}
/*
* Check that the amount of data in the buffers
* is as at least much as the IDP header would have us expect.
* Trim mbufs if longer than we expect.
* Drop packet if shorter than we expect.
*/
i = -len;
m0 = m;
for (;;) {
i += m->m_len;
if (m->m_next == 0)
break;
m = m->m_next;
}
if (i != 0) {
if (i < 0) {
idpstat.idps_tooshort++;
m = m0;
goto bad;
}
if (i <= m->m_len)
m->m_len -= i;
else
m_adj(m0, -i);
}
m = m0;
if (idpcksum && ((i = idp->idp_sum)!=0xffff)) {
idp->idp_sum = 0;
if (i != (idp->idp_sum = ns_cksum(m,len))) {
idpstat.idps_badsum++;
idp->idp_sum = i;
if (ns_hosteqnh(ns_thishost, idp->idp_dna.x_host))
error = NS_ERR_BADSUM;
else
error = NS_ERR_BADSUM_T;
ns_error(m, error, 0);
goto next;
}
}
/*
* Is this a directed broadcast?
*/
if (ns_hosteqnh(ns_broadhost,idp->idp_dna.x_host)) {
if ((!ns_neteq(idp->idp_dna, idp->idp_sna)) &&
(!ns_neteqnn(idp->idp_dna.x_net, ns_broadnet)) &&
(!ns_neteqnn(idp->idp_sna.x_net, ns_zeronet)) &&
(!ns_neteqnn(idp->idp_dna.x_net, ns_zeronet)) ) {
/*
* Look to see if I need to eat this packet.
* Algorithm is to forward all young packets
* and prematurely age any packets which will
* by physically broadcasted.
* Any very old packets eaten without forwarding
* would die anyway.
*
* Suggestion of Bill Nesheim, Cornell U.
*/
if (idp->idp_tc < NS_MAXHOPS) {
idp_forward(idp);
goto next;
}
}
/*
* Is this our packet? If not, forward.
*/
} else if (!ns_hosteqnh(ns_thishost,idp->idp_dna.x_host)) {
idp_forward(idp);
goto next;
}
/*
* Locate pcb for datagram.
*/
nsp = ns_pcblookup(&idp->idp_sna, idp->idp_dna.x_port, NS_WILDCARD);
/*
* Switch out to protocol's input routine.
*/
nsintr_swtch++;
if (nsp) {
if (oddpacketp) {
m_adj(m0, -1);
}
if ((nsp->nsp_flags & NSP_ALL_PACKETS)==0)
switch (idp->idp_pt) {
case NSPROTO_SPP:
spp_input(m, nsp, ifp);
goto next;
case NSPROTO_ERROR:
ns_err_input(m);
goto next;
}
idp_input(m, nsp, ifp);
} else {
ns_error(m, NS_ERR_NOSOCK, 0);
}
goto next;
bad:
m_freem(m);
goto next;
}
u_char nsctlerrmap[PRC_NCMDS] = {
ECONNABORTED, ECONNABORTED, 0, 0,
0, 0, EHOSTDOWN, EHOSTUNREACH,
ENETUNREACH, EHOSTUNREACH, ECONNREFUSED, ECONNREFUSED,
EMSGSIZE, 0, 0, 0,
0, 0, 0, 0
};
idp_donosocks = 1;
idp_ctlinput(cmd, arg)
int cmd;
caddr_t arg;
{
struct ns_addr *ns;
struct nspcb *nsp;
struct ns_errp *errp;
int idp_abort();
extern struct nspcb *idp_drop();
int type;
if (cmd < 0 || cmd > PRC_NCMDS)
return;
if (nsctlerrmap[cmd] == 0)
return; /* XXX */
type = NS_ERR_UNREACH_HOST;
switch (cmd) {
struct sockaddr_ns *sns;
case PRC_IFDOWN:
case PRC_HOSTDEAD:
case PRC_HOSTUNREACH:
sns = (struct sockaddr_ns *)arg;
if (sns->sns_family != AF_INET)
return;
ns = &sns->sns_addr;
break;
default:
errp = (struct ns_errp *)arg;
ns = &errp->ns_err_idp.idp_dna;
type = errp->ns_err_num;
type = ntohs((u_short)type);
}
switch (type) {
case NS_ERR_UNREACH_HOST:
ns_pcbnotify(ns, (int)nsctlerrmap[cmd], idp_abort, (long)0);
break;
case NS_ERR_NOSOCK:
nsp = ns_pcblookup(ns, errp->ns_err_idp.idp_sna.x_port,
NS_WILDCARD);
if(nsp && idp_donosocks && ! ns_nullhost(nsp->nsp_faddr))
(void) idp_drop(nsp, (int)nsctlerrmap[cmd]);
}
}
int idpprintfs = 0;
int idpforwarding = 1;
/*
* Forward a packet. If some error occurs return the sender
* an error packet. Note we can't always generate a meaningful
* error message because the NS errors don't have a large enough repetoire
* of codes and types.
*/
struct route idp_droute;
struct route idp_sroute;
idp_forward(idp)
register struct idp *idp;
{
register int error, type, code;
struct mbuf *mcopy = NULL;
int agedelta = 1;
int flags = NS_FORWARDING;
int ok_there = 0;
int ok_back = 0;
if (idpprintfs) {
printf("forward: src ");
ns_printhost(&idp->idp_sna);
printf(", dst ");
ns_printhost(&idp->idp_dna);
printf("hop count %d\n", idp->idp_tc);
}
if (idpforwarding == 0) {
/* can't tell difference between net and host */
type = NS_ERR_UNREACH_HOST, code = 0;
goto senderror;
}
idp->idp_tc++;
if (idp->idp_tc > NS_MAXHOPS) {
type = NS_ERR_TOO_OLD, code = 0;
goto senderror;
}
/*
* Save at most 42 bytes of the packet in case
* we need to generate an NS error message to the src.
*/
mcopy = m_copy(dtom(idp), 0, imin((int)ntohs(idp->idp_len), 42));
if ((ok_there = idp_do_route(&idp->idp_dna,&idp_droute))==0) {
type = NS_ERR_UNREACH_HOST, code = 0;
goto senderror;
}
/*
* Here we think about forwarding broadcast packets,
* so we try to insure that it doesn't go back out
* on the interface it came in on. Also, if we
* are going to physically broadcast this, let us
* age the packet so we can eat it safely the second time around.
*/
if (idp->idp_dna.x_host.c_host[0] & 0x1) {
struct ns_ifaddr *ia = ns_iaonnetof(&idp->idp_dna);
struct ifnet *ifp;
if (ia) {
/* I'm gonna hafta eat this packet */
agedelta += NS_MAXHOPS - idp->idp_tc;
idp->idp_tc = NS_MAXHOPS;
}
if ((ok_back = idp_do_route(&idp->idp_sna,&idp_sroute))==0) {
/* error = ENETUNREACH; He'll never get it! */
m_freem(dtom(idp));
goto cleanup;
}
if (idp_droute.ro_rt &&
(ifp=idp_droute.ro_rt->rt_ifp) &&
idp_sroute.ro_rt &&
(ifp!=idp_sroute.ro_rt->rt_ifp)) {
flags |= NS_ALLOWBROADCAST;
} else {
type = NS_ERR_UNREACH_HOST, code = 0;
goto senderror;
}
}
/* need to adjust checksum */
if (idp->idp_sum!=0xffff) {
union bytes {
u_char c[4];
u_short s[2];
long l;
} x;
register int shift;
x.l = 0; x.c[0] = agedelta;
shift = (((((int)ntohs(idp->idp_len))+1)>>1)-2) & 0xf;
x.l = idp->idp_sum + (x.l << shift);
x.l = x.s[0] + x.s[1];
x.l = x.s[0] + x.s[1];
if (x.l==0xffff) idp->idp_sum = 0; else idp->idp_sum = x.l;
}
if ((error = ns_output(dtom(idp), &idp_droute, flags)) &&
(mcopy!=NULL)) {
idp = mtod(mcopy, struct idp *);
type = NS_ERR_UNSPEC_T, code = 0;
switch (error) {
case ENETUNREACH:
case EHOSTDOWN:
case EHOSTUNREACH:
case ENETDOWN:
case EPERM:
type = NS_ERR_UNREACH_HOST;
break;
case EMSGSIZE:
type = NS_ERR_TOO_BIG;
code = 576; /* too hard to figure out mtu here */
break;
case ENOBUFS:
type = NS_ERR_UNSPEC_T;
break;
}
mcopy = NULL;
senderror:
ns_error(dtom(idp), type, code);
}
cleanup:
if (ok_there)
idp_undo_route(&idp_droute);
if (ok_back)
idp_undo_route(&idp_sroute);
if (mcopy != NULL)
m_freem(mcopy);
}
idp_do_route(src, ro)
struct ns_addr *src;
struct route *ro;
{
struct sockaddr_ns *dst;
bzero((caddr_t)ro, sizeof (*ro));
dst = (struct sockaddr_ns *)&ro->ro_dst;
dst->sns_family = AF_NS;
dst->sns_addr = *src;
dst->sns_addr.x_port = 0;
rtalloc(ro);
if (ro->ro_rt == 0 || ro->ro_rt->rt_ifp == 0) {
return (0);
}
ro->ro_rt->rt_use++;
return (1);
}
idp_undo_route(ro)
register struct route *ro;
{
if (ro->ro_rt) {RTFREE(ro->ro_rt);}
}
static union ns_net
ns_zeronet;
ns_watch_output(m, ifp)
struct mbuf *m;
struct ifnet *ifp;
{
register struct nspcb *nsp;
register struct ifaddr *ia;
/*
* Give any raw listeners a crack at the packet
*/
for (nsp = nsrawpcb.nsp_next; nsp != &nsrawpcb; nsp = nsp->nsp_next) {
struct mbuf *m0 = m_copy(m, 0, (int)M_COPYALL);
if (m0) {
struct mbuf *m1 = m_get(M_DONTWAIT, MT_DATA);
if(m1 == NULL)
m_freem(m0);
else {
register struct idp *idp;
m1->m_off = MMINOFF;
m1->m_len = sizeof (*idp);
m1->m_next = m0;
idp = mtod(m1, struct idp *);
idp->idp_sna.x_net = ns_zeronet;
idp->idp_sna.x_host = ns_thishost;
if (ifp && (ifp->if_flags & IFF_POINTOPOINT))
for(ia = ifp->if_addrlist; ia;
ia = ia->ifa_next) {
if (ia->ifa_addr.sa_family==AF_NS) {
idp->idp_sna =
satons_addr(ia->ifa_dstaddr);
break;
}
}
idp->idp_len = 0xffff;
idp_input(m1, nsp, ifp);
}
}
}
}
#endif NS