2 * Copyright (c) 1982, 1986, 1988, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 * @(#)ip_input.c 8.2 (Berkeley) 1/4/94
30 * ip_input.c,v 1.11 1994/11/16 10:17:08 jkh Exp
34 * Changes and additions relating to SLiRP are
35 * Copyright (c) 1995 Danny Gasparovski.
37 * Please read the file COPYRIGHT for the
38 * terms and conditions of the copyright.
45 static struct ip
*ip_reass(Slirp
*slirp
, struct ip
*ip
, struct ipq
*fp
);
46 static void ip_freef(Slirp
*slirp
, struct ipq
*fp
);
47 static void ip_enq(register struct ipasfrag
*p
,
48 register struct ipasfrag
*prev
);
49 static void ip_deq(register struct ipasfrag
*p
);
52 * IP initialization: fill in IP protocol switch table.
53 * All protocols not implemented in kernel go to raw IP protocol handler.
58 slirp
->ipq
.ip_link
.next
= slirp
->ipq
.ip_link
.prev
= &slirp
->ipq
.ip_link
;
64 void ip_cleanup(Slirp
*slirp
)
72 * Ip input routine. Checksum and byte swap header. If fragmented
73 * try to reassemble. Process options. Pass to next level.
76 ip_input(struct mbuf
*m
)
78 Slirp
*slirp
= m
->slirp
;
79 register struct ip
*ip
;
82 DEBUG_CALL("ip_input");
83 DEBUG_ARG("m = %lx", (long)m
);
84 DEBUG_ARG("m_len = %d", m
->m_len
);
86 if (m
->m_len
< sizeof (struct ip
)) {
90 ip
= mtod(m
, struct ip
*);
92 if (ip
->ip_v
!= IPVERSION
) {
96 hlen
= ip
->ip_hl
<< 2;
97 if (hlen
<sizeof(struct ip
) || hlen
>m
->m_len
) {/* min header length */
98 goto bad
; /* or packet too short */
101 /* keep ip header intact for ICMP reply
102 * ip->ip_sum = cksum(m, hlen);
110 * Convert fields to host representation.
113 if (ip
->ip_len
< hlen
) {
120 * Check that the amount of data in the buffers
121 * is as at least much as the IP header would have us expect.
122 * Trim mbufs if longer than we expect.
123 * Drop packet if shorter than we expect.
125 if (m
->m_len
< ip
->ip_len
) {
129 /* Should drop packet if mbuf too long? hmmm... */
130 if (m
->m_len
> ip
->ip_len
)
131 m_adj(m
, ip
->ip_len
- m
->m_len
);
133 /* check ip_ttl for a correct ICMP reply */
135 icmp_error(m
, ICMP_TIMXCEED
,ICMP_TIMXCEED_INTRANS
, 0,"ttl");
140 * If offset or IP_MF are set, must reassemble.
141 * Otherwise, nothing need be done.
142 * (We could look in the reassembly queue to see
143 * if the packet was previously fragmented,
144 * but it's not worth the time; just let them time out.)
146 * XXX This should fail, don't fragment yet
148 if (ip
->ip_off
&~ IP_DF
) {
149 register struct ipq
*fp
;
152 * Look for queue of fragments
155 for (l
= slirp
->ipq
.ip_link
.next
; l
!= &slirp
->ipq
.ip_link
;
157 fp
= container_of(l
, struct ipq
, ip_link
);
158 if (ip
->ip_id
== fp
->ipq_id
&&
159 ip
->ip_src
.s_addr
== fp
->ipq_src
.s_addr
&&
160 ip
->ip_dst
.s_addr
== fp
->ipq_dst
.s_addr
&&
161 ip
->ip_p
== fp
->ipq_p
)
168 * Adjust ip_len to not reflect header,
169 * set ip_mff if more fragments are expected,
170 * convert offset of this to bytes.
173 if (ip
->ip_off
& IP_MF
)
181 * If datagram marked as having more fragments
182 * or if this is not the first fragment,
183 * attempt reassembly; if it succeeds, proceed.
185 if (ip
->ip_tos
& 1 || ip
->ip_off
) {
186 ip
= ip_reass(slirp
, ip
, fp
);
198 * Switch out to protocol's input routine.
202 tcp_input(m
, hlen
, (struct socket
*)NULL
);
218 #define iptofrag(P) ((struct ipasfrag *)(((char*)(P)) - sizeof(struct qlink)))
219 #define fragtoip(P) ((struct ip*)(((char*)(P)) + sizeof(struct qlink)))
221 * Take incoming datagram fragment and try to
222 * reassemble it into whole datagram. If a chain for
223 * reassembly of this datagram already exists, then it
224 * is given as fp; otherwise have to make a chain.
227 ip_reass(Slirp
*slirp
, struct ip
*ip
, struct ipq
*fp
)
229 register struct mbuf
*m
= dtom(slirp
, ip
);
230 register struct ipasfrag
*q
;
231 int hlen
= ip
->ip_hl
<< 2;
234 DEBUG_CALL("ip_reass");
235 DEBUG_ARG("ip = %lx", (long)ip
);
236 DEBUG_ARG("fp = %lx", (long)fp
);
237 DEBUG_ARG("m = %lx", (long)m
);
240 * Presence of header sizes in mbufs
241 * would confuse code below.
242 * Fragment m_data is concatenated.
248 * If first fragment to arrive, create a reassembly queue.
251 struct mbuf
*t
= m_get(slirp
);
256 fp
= mtod(t
, struct ipq
*);
257 insque(&fp
->ip_link
, &slirp
->ipq
.ip_link
);
258 fp
->ipq_ttl
= IPFRAGTTL
;
259 fp
->ipq_p
= ip
->ip_p
;
260 fp
->ipq_id
= ip
->ip_id
;
261 fp
->frag_link
.next
= fp
->frag_link
.prev
= &fp
->frag_link
;
262 fp
->ipq_src
= ip
->ip_src
;
263 fp
->ipq_dst
= ip
->ip_dst
;
264 q
= (struct ipasfrag
*)fp
;
269 * Find a segment which begins after this one does.
271 for (q
= fp
->frag_link
.next
; q
!= (struct ipasfrag
*)&fp
->frag_link
;
273 if (q
->ipf_off
> ip
->ip_off
)
277 * If there is a preceding segment, it may provide some of
278 * our data already. If so, drop the data from the incoming
279 * segment. If it provides all of our data, drop us.
281 if (q
->ipf_prev
!= &fp
->frag_link
) {
282 struct ipasfrag
*pq
= q
->ipf_prev
;
283 i
= pq
->ipf_off
+ pq
->ipf_len
- ip
->ip_off
;
287 m_adj(dtom(slirp
, ip
), i
);
294 * While we overlap succeeding segments trim them or,
295 * if they are completely covered, dequeue them.
297 while (q
!= (struct ipasfrag
*)&fp
->frag_link
&&
298 ip
->ip_off
+ ip
->ip_len
> q
->ipf_off
) {
299 i
= (ip
->ip_off
+ ip
->ip_len
) - q
->ipf_off
;
300 if (i
< q
->ipf_len
) {
303 m_adj(dtom(slirp
, q
), i
);
307 m_free(dtom(slirp
, q
->ipf_prev
));
313 * Stick new segment in its place;
314 * check for complete reassembly.
316 ip_enq(iptofrag(ip
), q
->ipf_prev
);
318 for (q
= fp
->frag_link
.next
; q
!= (struct ipasfrag
*)&fp
->frag_link
;
320 if (q
->ipf_off
!= next
)
324 if (((struct ipasfrag
*)(q
->ipf_prev
))->ipf_tos
& 1)
328 * Reassembly is complete; concatenate fragments.
330 q
= fp
->frag_link
.next
;
333 q
= (struct ipasfrag
*) q
->ipf_next
;
334 while (q
!= (struct ipasfrag
*)&fp
->frag_link
) {
335 struct mbuf
*t
= dtom(slirp
, q
);
336 q
= (struct ipasfrag
*) q
->ipf_next
;
341 * Create header for new ip packet by
342 * modifying header of first packet;
343 * dequeue and discard fragment reassembly header.
344 * Make header visible.
346 q
= fp
->frag_link
.next
;
349 * If the fragments concatenated to an mbuf that's
350 * bigger than the total size of the fragment, then and
351 * m_ext buffer was alloced. But fp->ipq_next points to
352 * the old buffer (in the mbuf), so we must point ip
353 * into the new buffer.
355 if (m
->m_flags
& M_EXT
) {
356 int delta
= (char *)q
- m
->m_dat
;
357 q
= (struct ipasfrag
*)(m
->m_ext
+ delta
);
363 ip
->ip_src
= fp
->ipq_src
;
364 ip
->ip_dst
= fp
->ipq_dst
;
365 remque(&fp
->ip_link
);
366 (void) m_free(dtom(slirp
, fp
));
367 m
->m_len
+= (ip
->ip_hl
<< 2);
368 m
->m_data
-= (ip
->ip_hl
<< 2);
378 * Free a fragment reassembly header and all
379 * associated datagrams.
382 ip_freef(Slirp
*slirp
, struct ipq
*fp
)
384 register struct ipasfrag
*q
, *p
;
386 for (q
= fp
->frag_link
.next
; q
!= (struct ipasfrag
*)&fp
->frag_link
; q
= p
) {
389 m_free(dtom(slirp
, q
));
391 remque(&fp
->ip_link
);
392 (void) m_free(dtom(slirp
, fp
));
396 * Put an ip fragment on a reassembly chain.
397 * Like insque, but pointers in middle of structure.
400 ip_enq(register struct ipasfrag
*p
, register struct ipasfrag
*prev
)
402 DEBUG_CALL("ip_enq");
403 DEBUG_ARG("prev = %lx", (long)prev
);
405 p
->ipf_next
= prev
->ipf_next
;
406 ((struct ipasfrag
*)(prev
->ipf_next
))->ipf_prev
= p
;
411 * To ip_enq as remque is to insque.
414 ip_deq(register struct ipasfrag
*p
)
416 ((struct ipasfrag
*)(p
->ipf_prev
))->ipf_next
= p
->ipf_next
;
417 ((struct ipasfrag
*)(p
->ipf_next
))->ipf_prev
= p
->ipf_prev
;
421 * IP timer processing;
422 * if a timer expires on a reassembly
426 ip_slowtimo(Slirp
*slirp
)
430 DEBUG_CALL("ip_slowtimo");
432 l
= slirp
->ipq
.ip_link
.next
;
437 while (l
!= &slirp
->ipq
.ip_link
) {
438 struct ipq
*fp
= container_of(l
, struct ipq
, ip_link
);
440 if (--fp
->ipq_ttl
== 0) {
447 * Do option processing on a datagram,
448 * possibly discarding it if bad options are encountered,
449 * or forwarding it if source-routed.
450 * Returns 1 if packet has been forwarded/freed,
451 * 0 if the packet should be processed further.
460 register struct ip
*ip
= mtod(m
, struct ip
*);
462 register struct ip_timestamp
*ipt
;
463 register struct in_ifaddr
*ia
;
464 int opt
, optlen
, cnt
, off
, code
, type
, forward
= 0;
465 struct in_addr
*sin
, dst
;
466 typedef uint32_t n_time
;
470 cp
= (u_char
*)(ip
+ 1);
471 cnt
= (ip
->ip_hl
<< 2) - sizeof (struct ip
);
472 for (; cnt
> 0; cnt
-= optlen
, cp
+= optlen
) {
473 opt
= cp
[IPOPT_OPTVAL
];
474 if (opt
== IPOPT_EOL
)
476 if (opt
== IPOPT_NOP
)
479 optlen
= cp
[IPOPT_OLEN
];
480 if (optlen
<= 0 || optlen
> cnt
) {
481 code
= &cp
[IPOPT_OLEN
] - (u_char
*)ip
;
491 * Source routing with record.
492 * Find interface with current destination address.
493 * If none on this machine then drop if strictly routed,
494 * or do nothing if loosely routed.
495 * Record interface address and bring up next address
496 * component. If strictly routed make sure next
497 * address is on directly accessible net.
501 if ((off
= cp
[IPOPT_OFFSET
]) < IPOPT_MINOFF
) {
502 code
= &cp
[IPOPT_OFFSET
] - (u_char
*)ip
;
505 ipaddr
.sin_addr
= ip
->ip_dst
;
506 ia
= (struct in_ifaddr
*)
507 ifa_ifwithaddr((struct sockaddr
*)&ipaddr
);
509 if (opt
== IPOPT_SSRR
) {
511 code
= ICMP_UNREACH_SRCFAIL
;
515 * Loose routing, and not at next destination
516 * yet; nothing to do except forward.
520 off
--; /* 0 origin */
521 if (off
> optlen
- sizeof(struct in_addr
)) {
523 * End of source route. Should be for us.
525 save_rte(cp
, ip
->ip_src
);
529 * locate outgoing interface
531 bcopy((caddr_t
)(cp
+ off
), (caddr_t
)&ipaddr
.sin_addr
,
532 sizeof(ipaddr
.sin_addr
));
533 if (opt
== IPOPT_SSRR
) {
534 #define INA struct in_ifaddr *
535 #define SA struct sockaddr *
536 if ((ia
= (INA
)ifa_ifwithdstaddr((SA
)&ipaddr
)) == 0)
537 ia
= (INA
)ifa_ifwithnet((SA
)&ipaddr
);
539 ia
= ip_rtaddr(ipaddr
.sin_addr
);
542 code
= ICMP_UNREACH_SRCFAIL
;
545 ip
->ip_dst
= ipaddr
.sin_addr
;
546 bcopy((caddr_t
)&(IA_SIN(ia
)->sin_addr
),
547 (caddr_t
)(cp
+ off
), sizeof(struct in_addr
));
548 cp
[IPOPT_OFFSET
] += sizeof(struct in_addr
);
550 * Let ip_intr's mcast routing check handle mcast pkts
552 forward
= !IN_MULTICAST(ntohl(ip
->ip_dst
.s_addr
));
556 if ((off
= cp
[IPOPT_OFFSET
]) < IPOPT_MINOFF
) {
557 code
= &cp
[IPOPT_OFFSET
] - (u_char
*)ip
;
561 * If no space remains, ignore.
563 off
--; /* 0 origin */
564 if (off
> optlen
- sizeof(struct in_addr
))
566 bcopy((caddr_t
)(&ip
->ip_dst
), (caddr_t
)&ipaddr
.sin_addr
,
567 sizeof(ipaddr
.sin_addr
));
569 * locate outgoing interface; if we're the destination,
570 * use the incoming interface (should be same).
572 if ((ia
= (INA
)ifa_ifwithaddr((SA
)&ipaddr
)) == 0 &&
573 (ia
= ip_rtaddr(ipaddr
.sin_addr
)) == 0) {
575 code
= ICMP_UNREACH_HOST
;
578 bcopy((caddr_t
)&(IA_SIN(ia
)->sin_addr
),
579 (caddr_t
)(cp
+ off
), sizeof(struct in_addr
));
580 cp
[IPOPT_OFFSET
] += sizeof(struct in_addr
);
584 code
= cp
- (u_char
*)ip
;
585 ipt
= (struct ip_timestamp
*)cp
;
586 if (ipt
->ipt_len
< 5)
588 if (ipt
->ipt_ptr
> ipt
->ipt_len
- sizeof (int32_t)) {
589 if (++ipt
->ipt_oflw
== 0)
593 sin
= (struct in_addr
*)(cp
+ ipt
->ipt_ptr
- 1);
594 switch (ipt
->ipt_flg
) {
596 case IPOPT_TS_TSONLY
:
599 case IPOPT_TS_TSANDADDR
:
600 if (ipt
->ipt_ptr
+ sizeof(n_time
) +
601 sizeof(struct in_addr
) > ipt
->ipt_len
)
603 ipaddr
.sin_addr
= dst
;
604 ia
= (INA
)ifaof_ i f p
foraddr((SA
)&ipaddr
,
608 bcopy((caddr_t
)&IA_SIN(ia
)->sin_addr
,
609 (caddr_t
)sin
, sizeof(struct in_addr
));
610 ipt
->ipt_ptr
+= sizeof(struct in_addr
);
613 case IPOPT_TS_PRESPEC
:
614 if (ipt
->ipt_ptr
+ sizeof(n_time
) +
615 sizeof(struct in_addr
) > ipt
->ipt_len
)
617 bcopy((caddr_t
)sin
, (caddr_t
)&ipaddr
.sin_addr
,
618 sizeof(struct in_addr
));
619 if (ifa_ifwithaddr((SA
)&ipaddr
) == 0)
621 ipt
->ipt_ptr
+= sizeof(struct in_addr
);
628 bcopy((caddr_t
)&ntime
, (caddr_t
)cp
+ ipt
->ipt_ptr
- 1,
630 ipt
->ipt_ptr
+= sizeof(n_time
);
639 icmp_error(m
, type
, code
, 0, 0);
647 * Strip out IP options, at higher
648 * level protocol in the kernel.
649 * Second argument is buffer to which options
650 * will be moved, and return value is their length.
651 * (XXX) should be deleted; last arg currently ignored.
654 ip_stripoptions(register struct mbuf
*m
, struct mbuf
*mopt
)
657 struct ip
*ip
= mtod(m
, struct ip
*);
658 register caddr_t opts
;
661 olen
= (ip
->ip_hl
<<2) - sizeof (struct ip
);
662 opts
= (caddr_t
)(ip
+ 1);
663 i
= m
->m_len
- (sizeof (struct ip
) + olen
);
664 memcpy(opts
, opts
+ olen
, (unsigned)i
);
667 ip
->ip_hl
= sizeof(struct ip
) >> 2;