]>
git.proxmox.com Git - mirror_qemu.git/blob - slirp/ip_input.c
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.
41 #include "qemu/osdep.h"
43 #include <qemu/osdep.h>
46 static struct ip
*ip_reass(Slirp
*slirp
, struct ip
*ip
, struct ipq
*fp
);
47 static void ip_freef(Slirp
*slirp
, struct ipq
*fp
);
48 static void ip_enq(register struct ipasfrag
*p
,
49 register struct ipasfrag
*prev
);
50 static void ip_deq(register struct ipasfrag
*p
);
53 * IP initialization: fill in IP protocol switch table.
54 * All protocols not implemented in kernel go to raw IP protocol handler.
59 slirp
->ipq
.ip_link
.next
= slirp
->ipq
.ip_link
.prev
= &slirp
->ipq
.ip_link
;
65 void ip_cleanup(Slirp
*slirp
)
73 * Ip input routine. Checksum and byte swap header. If fragmented
74 * try to reassemble. Process options. Pass to next level.
77 ip_input(struct mbuf
*m
)
79 Slirp
*slirp
= m
->slirp
;
80 register struct ip
*ip
;
83 if (!slirp
->in_enabled
) {
87 DEBUG_CALL("ip_input");
88 DEBUG_ARG("m = %p", m
);
89 DEBUG_ARG("m_len = %d", m
->m_len
);
91 if (m
->m_len
< sizeof (struct ip
)) {
95 ip
= mtod(m
, struct ip
*);
97 if (ip
->ip_v
!= IPVERSION
) {
101 hlen
= ip
->ip_hl
<< 2;
102 if (hlen
<sizeof(struct ip
) || hlen
>m
->m_len
) {/* min header length */
103 goto bad
; /* or packet too short */
106 /* keep ip header intact for ICMP reply
107 * ip->ip_sum = cksum(m, hlen);
115 * Convert fields to host representation.
118 if (ip
->ip_len
< hlen
) {
125 * Check that the amount of data in the buffers
126 * is as at least much as the IP header would have us expect.
127 * Trim mbufs if longer than we expect.
128 * Drop packet if shorter than we expect.
130 if (m
->m_len
< ip
->ip_len
) {
134 /* Should drop packet if mbuf too long? hmmm... */
135 if (m
->m_len
> ip
->ip_len
)
136 m_adj(m
, ip
->ip_len
- m
->m_len
);
138 /* check ip_ttl for a correct ICMP reply */
139 if (ip
->ip_ttl
== 0) {
140 icmp_send_error(m
, ICMP_TIMXCEED
, ICMP_TIMXCEED_INTRANS
, 0, "ttl");
145 * If offset or IP_MF are set, must reassemble.
146 * Otherwise, nothing need be done.
147 * (We could look in the reassembly queue to see
148 * if the packet was previously fragmented,
149 * but it's not worth the time; just let them time out.)
151 * XXX This should fail, don't fragment yet
153 if (ip
->ip_off
&~ IP_DF
) {
154 register struct ipq
*fp
;
157 * Look for queue of fragments
160 for (l
= slirp
->ipq
.ip_link
.next
; l
!= &slirp
->ipq
.ip_link
;
162 fp
= container_of(l
, struct ipq
, ip_link
);
163 if (ip
->ip_id
== fp
->ipq_id
&&
164 ip
->ip_src
.s_addr
== fp
->ipq_src
.s_addr
&&
165 ip
->ip_dst
.s_addr
== fp
->ipq_dst
.s_addr
&&
166 ip
->ip_p
== fp
->ipq_p
)
173 * Adjust ip_len to not reflect header,
174 * set ip_mff if more fragments are expected,
175 * convert offset of this to bytes.
178 if (ip
->ip_off
& IP_MF
)
186 * If datagram marked as having more fragments
187 * or if this is not the first fragment,
188 * attempt reassembly; if it succeeds, proceed.
190 if (ip
->ip_tos
& 1 || ip
->ip_off
) {
191 ip
= ip_reass(slirp
, ip
, fp
);
203 * Switch out to protocol's input routine.
207 tcp_input(m
, hlen
, (struct socket
*)NULL
, AF_INET
);
223 #define iptofrag(P) ((struct ipasfrag *)(((char*)(P)) - sizeof(struct qlink)))
224 #define fragtoip(P) ((struct ip*)(((char*)(P)) + sizeof(struct qlink)))
226 * Take incoming datagram fragment and try to
227 * reassemble it into whole datagram. If a chain for
228 * reassembly of this datagram already exists, then it
229 * is given as fp; otherwise have to make a chain.
232 ip_reass(Slirp
*slirp
, struct ip
*ip
, struct ipq
*fp
)
234 register struct mbuf
*m
= dtom(slirp
, ip
);
235 register struct ipasfrag
*q
;
236 int hlen
= ip
->ip_hl
<< 2;
239 DEBUG_CALL("ip_reass");
240 DEBUG_ARG("ip = %p", ip
);
241 DEBUG_ARG("fp = %p", fp
);
242 DEBUG_ARG("m = %p", m
);
245 * Presence of header sizes in mbufs
246 * would confuse code below.
247 * Fragment m_data is concatenated.
253 * If first fragment to arrive, create a reassembly queue.
256 struct mbuf
*t
= m_get(slirp
);
261 fp
= mtod(t
, struct ipq
*);
262 insque(&fp
->ip_link
, &slirp
->ipq
.ip_link
);
263 fp
->ipq_ttl
= IPFRAGTTL
;
264 fp
->ipq_p
= ip
->ip_p
;
265 fp
->ipq_id
= ip
->ip_id
;
266 fp
->frag_link
.next
= fp
->frag_link
.prev
= &fp
->frag_link
;
267 fp
->ipq_src
= ip
->ip_src
;
268 fp
->ipq_dst
= ip
->ip_dst
;
269 q
= (struct ipasfrag
*)fp
;
274 * Find a segment which begins after this one does.
276 for (q
= fp
->frag_link
.next
; q
!= (struct ipasfrag
*)&fp
->frag_link
;
278 if (q
->ipf_off
> ip
->ip_off
)
282 * If there is a preceding segment, it may provide some of
283 * our data already. If so, drop the data from the incoming
284 * segment. If it provides all of our data, drop us.
286 if (q
->ipf_prev
!= &fp
->frag_link
) {
287 struct ipasfrag
*pq
= q
->ipf_prev
;
288 i
= pq
->ipf_off
+ pq
->ipf_len
- ip
->ip_off
;
292 m_adj(dtom(slirp
, ip
), i
);
299 * While we overlap succeeding segments trim them or,
300 * if they are completely covered, dequeue them.
302 while (q
!= (struct ipasfrag
*)&fp
->frag_link
&&
303 ip
->ip_off
+ ip
->ip_len
> q
->ipf_off
) {
304 i
= (ip
->ip_off
+ ip
->ip_len
) - q
->ipf_off
;
305 if (i
< q
->ipf_len
) {
308 m_adj(dtom(slirp
, q
), i
);
312 m_free(dtom(slirp
, q
->ipf_prev
));
318 * Stick new segment in its place;
319 * check for complete reassembly.
321 ip_enq(iptofrag(ip
), q
->ipf_prev
);
323 for (q
= fp
->frag_link
.next
; q
!= (struct ipasfrag
*)&fp
->frag_link
;
325 if (q
->ipf_off
!= next
)
329 if (((struct ipasfrag
*)(q
->ipf_prev
))->ipf_tos
& 1)
333 * Reassembly is complete; concatenate fragments.
335 q
= fp
->frag_link
.next
;
338 q
= (struct ipasfrag
*) q
->ipf_next
;
339 while (q
!= (struct ipasfrag
*)&fp
->frag_link
) {
340 struct mbuf
*t
= dtom(slirp
, q
);
341 q
= (struct ipasfrag
*) q
->ipf_next
;
346 * Create header for new ip packet by
347 * modifying header of first packet;
348 * dequeue and discard fragment reassembly header.
349 * Make header visible.
351 q
= fp
->frag_link
.next
;
354 * If the fragments concatenated to an mbuf that's
355 * bigger than the total size of the fragment, then and
356 * m_ext buffer was alloced. But fp->ipq_next points to
357 * the old buffer (in the mbuf), so we must point ip
358 * into the new buffer.
360 if (m
->m_flags
& M_EXT
) {
361 int delta
= (char *)q
- m
->m_dat
;
362 q
= (struct ipasfrag
*)(m
->m_ext
+ delta
);
368 ip
->ip_src
= fp
->ipq_src
;
369 ip
->ip_dst
= fp
->ipq_dst
;
370 remque(&fp
->ip_link
);
371 (void) m_free(dtom(slirp
, fp
));
372 m
->m_len
+= (ip
->ip_hl
<< 2);
373 m
->m_data
-= (ip
->ip_hl
<< 2);
383 * Free a fragment reassembly header and all
384 * associated datagrams.
387 ip_freef(Slirp
*slirp
, struct ipq
*fp
)
389 register struct ipasfrag
*q
, *p
;
391 for (q
= fp
->frag_link
.next
; q
!= (struct ipasfrag
*)&fp
->frag_link
; q
= p
) {
394 m_free(dtom(slirp
, q
));
396 remque(&fp
->ip_link
);
397 (void) m_free(dtom(slirp
, fp
));
401 * Put an ip fragment on a reassembly chain.
402 * Like insque, but pointers in middle of structure.
405 ip_enq(register struct ipasfrag
*p
, register struct ipasfrag
*prev
)
407 DEBUG_CALL("ip_enq");
408 DEBUG_ARG("prev = %p", prev
);
410 p
->ipf_next
= prev
->ipf_next
;
411 ((struct ipasfrag
*)(prev
->ipf_next
))->ipf_prev
= p
;
416 * To ip_enq as remque is to insque.
419 ip_deq(register struct ipasfrag
*p
)
421 ((struct ipasfrag
*)(p
->ipf_prev
))->ipf_next
= p
->ipf_next
;
422 ((struct ipasfrag
*)(p
->ipf_next
))->ipf_prev
= p
->ipf_prev
;
426 * IP timer processing;
427 * if a timer expires on a reassembly
431 ip_slowtimo(Slirp
*slirp
)
435 DEBUG_CALL("ip_slowtimo");
437 l
= slirp
->ipq
.ip_link
.next
;
442 while (l
!= &slirp
->ipq
.ip_link
) {
443 struct ipq
*fp
= container_of(l
, struct ipq
, ip_link
);
445 if (--fp
->ipq_ttl
== 0) {
452 * Do option processing on a datagram,
453 * possibly discarding it if bad options are encountered,
454 * or forwarding it if source-routed.
455 * Returns 1 if packet has been forwarded/freed,
456 * 0 if the packet should be processed further.
465 register struct ip
*ip
= mtod(m
, struct ip
*);
467 register struct ip_timestamp
*ipt
;
468 register struct in_ifaddr
*ia
;
469 int opt
, optlen
, cnt
, off
, code
, type
, forward
= 0;
470 struct in_addr
*sin
, dst
;
471 typedef uint32_t n_time
;
475 cp
= (u_char
*)(ip
+ 1);
476 cnt
= (ip
->ip_hl
<< 2) - sizeof (struct ip
);
477 for (; cnt
> 0; cnt
-= optlen
, cp
+= optlen
) {
478 opt
= cp
[IPOPT_OPTVAL
];
479 if (opt
== IPOPT_EOL
)
481 if (opt
== IPOPT_NOP
)
484 optlen
= cp
[IPOPT_OLEN
];
485 if (optlen
<= 0 || optlen
> cnt
) {
486 code
= &cp
[IPOPT_OLEN
] - (u_char
*)ip
;
496 * Source routing with record.
497 * Find interface with current destination address.
498 * If none on this machine then drop if strictly routed,
499 * or do nothing if loosely routed.
500 * Record interface address and bring up next address
501 * component. If strictly routed make sure next
502 * address is on directly accessible net.
506 if ((off
= cp
[IPOPT_OFFSET
]) < IPOPT_MINOFF
) {
507 code
= &cp
[IPOPT_OFFSET
] - (u_char
*)ip
;
510 ipaddr
.sin_addr
= ip
->ip_dst
;
511 ia
= (struct in_ifaddr
*)
512 ifa_ifwithaddr((struct sockaddr
*)&ipaddr
);
514 if (opt
== IPOPT_SSRR
) {
516 code
= ICMP_UNREACH_SRCFAIL
;
520 * Loose routing, and not at next destination
521 * yet; nothing to do except forward.
525 off
--; /* 0 origin */
526 if (off
> optlen
- sizeof(struct in_addr
)) {
528 * End of source route. Should be for us.
530 save_rte(cp
, ip
->ip_src
);
534 * locate outgoing interface
536 bcopy((caddr_t
)(cp
+ off
), (caddr_t
)&ipaddr
.sin_addr
,
537 sizeof(ipaddr
.sin_addr
));
538 if (opt
== IPOPT_SSRR
) {
539 #define INA struct in_ifaddr *
540 #define SA struct sockaddr *
541 if ((ia
= (INA
)ifa_ifwithdstaddr((SA
)&ipaddr
)) == 0)
542 ia
= (INA
)ifa_ifwithnet((SA
)&ipaddr
);
544 ia
= ip_rtaddr(ipaddr
.sin_addr
);
547 code
= ICMP_UNREACH_SRCFAIL
;
550 ip
->ip_dst
= ipaddr
.sin_addr
;
551 bcopy((caddr_t
)&(IA_SIN(ia
)->sin_addr
),
552 (caddr_t
)(cp
+ off
), sizeof(struct in_addr
));
553 cp
[IPOPT_OFFSET
] += sizeof(struct in_addr
);
555 * Let ip_intr's mcast routing check handle mcast pkts
557 forward
= !IN_MULTICAST(ntohl(ip
->ip_dst
.s_addr
));
561 if ((off
= cp
[IPOPT_OFFSET
]) < IPOPT_MINOFF
) {
562 code
= &cp
[IPOPT_OFFSET
] - (u_char
*)ip
;
566 * If no space remains, ignore.
568 off
--; /* 0 origin */
569 if (off
> optlen
- sizeof(struct in_addr
))
571 bcopy((caddr_t
)(&ip
->ip_dst
), (caddr_t
)&ipaddr
.sin_addr
,
572 sizeof(ipaddr
.sin_addr
));
574 * locate outgoing interface; if we're the destination,
575 * use the incoming interface (should be same).
577 if ((ia
= (INA
)ifa_ifwithaddr((SA
)&ipaddr
)) == 0 &&
578 (ia
= ip_rtaddr(ipaddr
.sin_addr
)) == 0) {
580 code
= ICMP_UNREACH_HOST
;
583 bcopy((caddr_t
)&(IA_SIN(ia
)->sin_addr
),
584 (caddr_t
)(cp
+ off
), sizeof(struct in_addr
));
585 cp
[IPOPT_OFFSET
] += sizeof(struct in_addr
);
589 code
= cp
- (u_char
*)ip
;
590 ipt
= (struct ip_timestamp
*)cp
;
591 if (ipt
->ipt_len
< 5)
593 if (ipt
->ipt_ptr
> ipt
->ipt_len
- sizeof (int32_t)) {
594 if (++ipt
->ipt_oflw
== 0)
598 sin
= (struct in_addr
*)(cp
+ ipt
->ipt_ptr
- 1);
599 switch (ipt
->ipt_flg
) {
601 case IPOPT_TS_TSONLY
:
604 case IPOPT_TS_TSANDADDR
:
605 if (ipt
->ipt_ptr
+ sizeof(n_time
) +
606 sizeof(struct in_addr
) > ipt
->ipt_len
)
608 ipaddr
.sin_addr
= dst
;
609 ia
= (INA
)ifaof_ i f p
foraddr((SA
)&ipaddr
,
613 bcopy((caddr_t
)&IA_SIN(ia
)->sin_addr
,
614 (caddr_t
)sin
, sizeof(struct in_addr
));
615 ipt
->ipt_ptr
+= sizeof(struct in_addr
);
618 case IPOPT_TS_PRESPEC
:
619 if (ipt
->ipt_ptr
+ sizeof(n_time
) +
620 sizeof(struct in_addr
) > ipt
->ipt_len
)
622 bcopy((caddr_t
)sin
, (caddr_t
)&ipaddr
.sin_addr
,
623 sizeof(struct in_addr
));
624 if (ifa_ifwithaddr((SA
)&ipaddr
) == 0)
626 ipt
->ipt_ptr
+= sizeof(struct in_addr
);
633 bcopy((caddr_t
)&ntime
, (caddr_t
)cp
+ ipt
->ipt_ptr
- 1,
635 ipt
->ipt_ptr
+= sizeof(n_time
);
644 icmp_send_error(m
, type
, code
, 0, 0);
652 * Strip out IP options, at higher
653 * level protocol in the kernel.
654 * Second argument is buffer to which options
655 * will be moved, and return value is their length.
656 * (XXX) should be deleted; last arg currently ignored.
659 ip_stripoptions(register struct mbuf
*m
, struct mbuf
*mopt
)
662 struct ip
*ip
= mtod(m
, struct ip
*);
663 register caddr_t opts
;
666 olen
= (ip
->ip_hl
<<2) - sizeof (struct ip
);
667 opts
= (caddr_t
)(ip
+ 1);
668 i
= m
->m_len
- (sizeof (struct ip
) + olen
);
669 memcpy(opts
, opts
+ olen
, (unsigned)i
);
672 ip
->ip_hl
= sizeof(struct ip
) >> 2;