472 lines
12 KiB
C
472 lines
12 KiB
C
/*
|
|
* Copyright (c) 1982, 1986, 1988, 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
* SUCH DAMAGE.
|
|
*
|
|
* @(#)ip_input.c 8.2 (Berkeley) 1/4/94
|
|
* ip_input.c,v 1.11 1994/11/16 10:17:08 jkh Exp
|
|
*/
|
|
|
|
/*
|
|
* Changes and additions relating to SLiRP are
|
|
* Copyright (c) 1995 Danny Gasparovski.
|
|
*
|
|
* Please read the file COPYRIGHT for the
|
|
* terms and conditions of the copyright.
|
|
*/
|
|
|
|
#include "slirp.h"
|
|
#include "ip_icmp.h"
|
|
|
|
static struct ip *ip_reass(Slirp *slirp, struct ip *ip, struct ipq *fp);
|
|
static void ip_freef(Slirp *slirp, struct ipq *fp);
|
|
static void ip_enq(register struct ipasfrag *p,
|
|
register struct ipasfrag *prev);
|
|
static void ip_deq(register struct ipasfrag *p);
|
|
|
|
/*
|
|
* IP initialization: fill in IP protocol switch table.
|
|
* All protocols not implemented in kernel go to raw IP protocol handler.
|
|
*/
|
|
void
|
|
ip_init(Slirp *slirp)
|
|
{
|
|
slirp->ipq.ip_link.next = slirp->ipq.ip_link.prev = &slirp->ipq.ip_link;
|
|
udp_init(slirp);
|
|
tcp_init(slirp);
|
|
icmp_init(slirp);
|
|
}
|
|
|
|
void ip_cleanup(Slirp *slirp)
|
|
{
|
|
udp_cleanup(slirp);
|
|
tcp_cleanup(slirp);
|
|
icmp_cleanup(slirp);
|
|
}
|
|
|
|
/*
|
|
* Ip input routine. Checksum and byte swap header. If fragmented
|
|
* try to reassemble. Process options. Pass to next level.
|
|
*/
|
|
void
|
|
ip_input(struct mbuf *m)
|
|
{
|
|
Slirp *slirp = m->slirp;
|
|
register struct ip *ip;
|
|
int hlen;
|
|
|
|
if (!slirp->in_enabled) {
|
|
goto bad;
|
|
}
|
|
|
|
DEBUG_CALL("ip_input");
|
|
DEBUG_ARG("m = %p", m);
|
|
DEBUG_ARG("m_len = %d", m->m_len);
|
|
|
|
if (m->m_len < sizeof (struct ip)) {
|
|
goto bad;
|
|
}
|
|
|
|
ip = mtod(m, struct ip *);
|
|
|
|
if (ip->ip_v != IPVERSION) {
|
|
goto bad;
|
|
}
|
|
|
|
hlen = ip->ip_hl << 2;
|
|
if (hlen<sizeof(struct ip ) || hlen>m->m_len) {/* min header length */
|
|
goto bad; /* or packet too short */
|
|
}
|
|
|
|
/* keep ip header intact for ICMP reply
|
|
* ip->ip_sum = cksum(m, hlen);
|
|
* if (ip->ip_sum) {
|
|
*/
|
|
if(cksum(m,hlen)) {
|
|
goto bad;
|
|
}
|
|
|
|
/*
|
|
* Convert fields to host representation.
|
|
*/
|
|
NTOHS(ip->ip_len);
|
|
if (ip->ip_len < hlen) {
|
|
goto bad;
|
|
}
|
|
NTOHS(ip->ip_id);
|
|
NTOHS(ip->ip_off);
|
|
|
|
/*
|
|
* Check that the amount of data in the buffers
|
|
* is as at least much as the IP header would have us expect.
|
|
* Trim mbufs if longer than we expect.
|
|
* Drop packet if shorter than we expect.
|
|
*/
|
|
if (m->m_len < ip->ip_len) {
|
|
goto bad;
|
|
}
|
|
|
|
/* Should drop packet if mbuf too long? hmmm... */
|
|
if (m->m_len > ip->ip_len)
|
|
m_adj(m, ip->ip_len - m->m_len);
|
|
|
|
/* check ip_ttl for a correct ICMP reply */
|
|
if (ip->ip_ttl == 0) {
|
|
icmp_send_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 0, "ttl");
|
|
goto bad;
|
|
}
|
|
|
|
/*
|
|
* If offset or IP_MF are set, must reassemble.
|
|
* Otherwise, nothing need be done.
|
|
* (We could look in the reassembly queue to see
|
|
* if the packet was previously fragmented,
|
|
* but it's not worth the time; just let them time out.)
|
|
*
|
|
* XXX This should fail, don't fragment yet
|
|
*/
|
|
if (ip->ip_off &~ IP_DF) {
|
|
register struct ipq *fp;
|
|
struct qlink *l;
|
|
/*
|
|
* Look for queue of fragments
|
|
* of this datagram.
|
|
*/
|
|
for (l = slirp->ipq.ip_link.next; l != &slirp->ipq.ip_link;
|
|
l = l->next) {
|
|
fp = container_of(l, struct ipq, ip_link);
|
|
if (ip->ip_id == fp->ipq_id &&
|
|
ip->ip_src.s_addr == fp->ipq_src.s_addr &&
|
|
ip->ip_dst.s_addr == fp->ipq_dst.s_addr &&
|
|
ip->ip_p == fp->ipq_p)
|
|
goto found;
|
|
}
|
|
fp = NULL;
|
|
found:
|
|
|
|
/*
|
|
* Adjust ip_len to not reflect header,
|
|
* set ip_mff if more fragments are expected,
|
|
* convert offset of this to bytes.
|
|
*/
|
|
ip->ip_len -= hlen;
|
|
if (ip->ip_off & IP_MF)
|
|
ip->ip_tos |= 1;
|
|
else
|
|
ip->ip_tos &= ~1;
|
|
|
|
ip->ip_off <<= 3;
|
|
|
|
/*
|
|
* If datagram marked as having more fragments
|
|
* or if this is not the first fragment,
|
|
* attempt reassembly; if it succeeds, proceed.
|
|
*/
|
|
if (ip->ip_tos & 1 || ip->ip_off) {
|
|
ip = ip_reass(slirp, ip, fp);
|
|
if (ip == NULL)
|
|
return;
|
|
m = dtom(slirp, ip);
|
|
} else
|
|
if (fp)
|
|
ip_freef(slirp, fp);
|
|
|
|
} else
|
|
ip->ip_len -= hlen;
|
|
|
|
/*
|
|
* Switch out to protocol's input routine.
|
|
*/
|
|
switch (ip->ip_p) {
|
|
case IPPROTO_TCP:
|
|
tcp_input(m, hlen, (struct socket *)NULL, AF_INET);
|
|
break;
|
|
case IPPROTO_UDP:
|
|
udp_input(m, hlen);
|
|
break;
|
|
case IPPROTO_ICMP:
|
|
icmp_input(m, hlen);
|
|
break;
|
|
default:
|
|
m_free(m);
|
|
}
|
|
return;
|
|
bad:
|
|
m_free(m);
|
|
}
|
|
|
|
#define iptofrag(P) ((struct ipasfrag *)(((char*)(P)) - sizeof(struct qlink)))
|
|
#define fragtoip(P) ((struct ip*)(((char*)(P)) + sizeof(struct qlink)))
|
|
/*
|
|
* Take incoming datagram fragment and try to
|
|
* reassemble it into whole datagram. If a chain for
|
|
* reassembly of this datagram already exists, then it
|
|
* is given as fp; otherwise have to make a chain.
|
|
*/
|
|
static struct ip *
|
|
ip_reass(Slirp *slirp, struct ip *ip, struct ipq *fp)
|
|
{
|
|
register struct mbuf *m = dtom(slirp, ip);
|
|
register struct ipasfrag *q;
|
|
int hlen = ip->ip_hl << 2;
|
|
int i, next;
|
|
|
|
DEBUG_CALL("ip_reass");
|
|
DEBUG_ARG("ip = %p", ip);
|
|
DEBUG_ARG("fp = %p", fp);
|
|
DEBUG_ARG("m = %p", m);
|
|
|
|
/*
|
|
* Presence of header sizes in mbufs
|
|
* would confuse code below.
|
|
* Fragment m_data is concatenated.
|
|
*/
|
|
m->m_data += hlen;
|
|
m->m_len -= hlen;
|
|
|
|
/*
|
|
* If first fragment to arrive, create a reassembly queue.
|
|
*/
|
|
if (fp == NULL) {
|
|
struct mbuf *t = m_get(slirp);
|
|
|
|
if (t == NULL) {
|
|
goto dropfrag;
|
|
}
|
|
fp = mtod(t, struct ipq *);
|
|
insque(&fp->ip_link, &slirp->ipq.ip_link);
|
|
fp->ipq_ttl = IPFRAGTTL;
|
|
fp->ipq_p = ip->ip_p;
|
|
fp->ipq_id = ip->ip_id;
|
|
fp->frag_link.next = fp->frag_link.prev = &fp->frag_link;
|
|
fp->ipq_src = ip->ip_src;
|
|
fp->ipq_dst = ip->ip_dst;
|
|
q = (struct ipasfrag *)fp;
|
|
goto insert;
|
|
}
|
|
|
|
/*
|
|
* Find a segment which begins after this one does.
|
|
*/
|
|
for (q = fp->frag_link.next; q != (struct ipasfrag *)&fp->frag_link;
|
|
q = q->ipf_next)
|
|
if (q->ipf_off > ip->ip_off)
|
|
break;
|
|
|
|
/*
|
|
* If there is a preceding segment, it may provide some of
|
|
* our data already. If so, drop the data from the incoming
|
|
* segment. If it provides all of our data, drop us.
|
|
*/
|
|
if (q->ipf_prev != &fp->frag_link) {
|
|
struct ipasfrag *pq = q->ipf_prev;
|
|
i = pq->ipf_off + pq->ipf_len - ip->ip_off;
|
|
if (i > 0) {
|
|
if (i >= ip->ip_len)
|
|
goto dropfrag;
|
|
m_adj(dtom(slirp, ip), i);
|
|
ip->ip_off += i;
|
|
ip->ip_len -= i;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* While we overlap succeeding segments trim them or,
|
|
* if they are completely covered, dequeue them.
|
|
*/
|
|
while (q != (struct ipasfrag*)&fp->frag_link &&
|
|
ip->ip_off + ip->ip_len > q->ipf_off) {
|
|
i = (ip->ip_off + ip->ip_len) - q->ipf_off;
|
|
if (i < q->ipf_len) {
|
|
q->ipf_len -= i;
|
|
q->ipf_off += i;
|
|
m_adj(dtom(slirp, q), i);
|
|
break;
|
|
}
|
|
q = q->ipf_next;
|
|
m_free(dtom(slirp, q->ipf_prev));
|
|
ip_deq(q->ipf_prev);
|
|
}
|
|
|
|
insert:
|
|
/*
|
|
* Stick new segment in its place;
|
|
* check for complete reassembly.
|
|
*/
|
|
ip_enq(iptofrag(ip), q->ipf_prev);
|
|
next = 0;
|
|
for (q = fp->frag_link.next; q != (struct ipasfrag*)&fp->frag_link;
|
|
q = q->ipf_next) {
|
|
if (q->ipf_off != next)
|
|
return NULL;
|
|
next += q->ipf_len;
|
|
}
|
|
if (((struct ipasfrag *)(q->ipf_prev))->ipf_tos & 1)
|
|
return NULL;
|
|
|
|
/*
|
|
* Reassembly is complete; concatenate fragments.
|
|
*/
|
|
q = fp->frag_link.next;
|
|
m = dtom(slirp, q);
|
|
|
|
q = (struct ipasfrag *) q->ipf_next;
|
|
while (q != (struct ipasfrag*)&fp->frag_link) {
|
|
struct mbuf *t = dtom(slirp, q);
|
|
q = (struct ipasfrag *) q->ipf_next;
|
|
m_cat(m, t);
|
|
}
|
|
|
|
/*
|
|
* Create header for new ip packet by
|
|
* modifying header of first packet;
|
|
* dequeue and discard fragment reassembly header.
|
|
* Make header visible.
|
|
*/
|
|
q = fp->frag_link.next;
|
|
|
|
/*
|
|
* If the fragments concatenated to an mbuf that's
|
|
* bigger than the total size of the fragment, then and
|
|
* m_ext buffer was alloced. But fp->ipq_next points to
|
|
* the old buffer (in the mbuf), so we must point ip
|
|
* into the new buffer.
|
|
*/
|
|
if (m->m_flags & M_EXT) {
|
|
int delta = (char *)q - m->m_dat;
|
|
q = (struct ipasfrag *)(m->m_ext + delta);
|
|
}
|
|
|
|
ip = fragtoip(q);
|
|
ip->ip_len = next;
|
|
ip->ip_tos &= ~1;
|
|
ip->ip_src = fp->ipq_src;
|
|
ip->ip_dst = fp->ipq_dst;
|
|
remque(&fp->ip_link);
|
|
(void) m_free(dtom(slirp, fp));
|
|
m->m_len += (ip->ip_hl << 2);
|
|
m->m_data -= (ip->ip_hl << 2);
|
|
|
|
return ip;
|
|
|
|
dropfrag:
|
|
m_free(m);
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* Free a fragment reassembly header and all
|
|
* associated datagrams.
|
|
*/
|
|
static void
|
|
ip_freef(Slirp *slirp, struct ipq *fp)
|
|
{
|
|
register struct ipasfrag *q, *p;
|
|
|
|
for (q = fp->frag_link.next; q != (struct ipasfrag*)&fp->frag_link; q = p) {
|
|
p = q->ipf_next;
|
|
ip_deq(q);
|
|
m_free(dtom(slirp, q));
|
|
}
|
|
remque(&fp->ip_link);
|
|
(void) m_free(dtom(slirp, fp));
|
|
}
|
|
|
|
/*
|
|
* Put an ip fragment on a reassembly chain.
|
|
* Like insque, but pointers in middle of structure.
|
|
*/
|
|
static void
|
|
ip_enq(register struct ipasfrag *p, register struct ipasfrag *prev)
|
|
{
|
|
DEBUG_CALL("ip_enq");
|
|
DEBUG_ARG("prev = %p", prev);
|
|
p->ipf_prev = prev;
|
|
p->ipf_next = prev->ipf_next;
|
|
((struct ipasfrag *)(prev->ipf_next))->ipf_prev = p;
|
|
prev->ipf_next = p;
|
|
}
|
|
|
|
/*
|
|
* To ip_enq as remque is to insque.
|
|
*/
|
|
static void
|
|
ip_deq(register struct ipasfrag *p)
|
|
{
|
|
((struct ipasfrag *)(p->ipf_prev))->ipf_next = p->ipf_next;
|
|
((struct ipasfrag *)(p->ipf_next))->ipf_prev = p->ipf_prev;
|
|
}
|
|
|
|
/*
|
|
* IP timer processing;
|
|
* if a timer expires on a reassembly
|
|
* queue, discard it.
|
|
*/
|
|
void
|
|
ip_slowtimo(Slirp *slirp)
|
|
{
|
|
struct qlink *l;
|
|
|
|
DEBUG_CALL("ip_slowtimo");
|
|
|
|
l = slirp->ipq.ip_link.next;
|
|
|
|
if (l == NULL)
|
|
return;
|
|
|
|
while (l != &slirp->ipq.ip_link) {
|
|
struct ipq *fp = container_of(l, struct ipq, ip_link);
|
|
l = l->next;
|
|
if (--fp->ipq_ttl == 0) {
|
|
ip_freef(slirp, fp);
|
|
}
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Strip out IP options, at higher
|
|
* level protocol in the kernel.
|
|
* Second argument is buffer to which options
|
|
* will be moved, and return value is their length.
|
|
* (XXX) should be deleted; last arg currently ignored.
|
|
*/
|
|
void
|
|
ip_stripoptions(register struct mbuf *m, struct mbuf *mopt)
|
|
{
|
|
register int i;
|
|
struct ip *ip = mtod(m, struct ip *);
|
|
register char *opts;
|
|
int olen;
|
|
|
|
olen = (ip->ip_hl<<2) - sizeof (struct ip);
|
|
opts = (char *)(ip + 1);
|
|
i = m->m_len - (sizeof (struct ip) + olen);
|
|
memcpy(opts, opts + olen, (unsigned)i);
|
|
m->m_len -= olen;
|
|
|
|
ip->ip_hl = sizeof(struct ip) >> 2;
|
|
}
|