2 * INET An implementation of the TCP/IP protocol suite for the LINUX
3 * operating system. INET is implemented using the BSD Socket
4 * interface as the means of communication with the user level.
6 * The options processing module for ip.c
8 * Version: $Id: ip_options.c,v 1.21 2001/09/01 00:31:50 davem Exp $
10 * Authors: A.N.Kuznetsov
14 #include <linux/capability.h>
15 #include <linux/module.h>
16 #include <linux/types.h>
17 #include <asm/uaccess.h>
18 #include <linux/skbuff.h>
20 #include <linux/icmp.h>
21 #include <linux/netdevice.h>
22 #include <linux/rtnetlink.h>
26 #include <net/route.h>
27 #include <net/cipso_ipv4.h>
30 * Write options to IP header, record destination address to
31 * source route option, address of outgoing interface
32 * (we should already know it, so that this function is allowed be
33 * called only after routing decision) and timestamp,
34 * if we originate this datagram.
36 * daddr is real destination address, next hop is recorded in IP header.
37 * saddr is address of outgoing interface.
40 void ip_options_build(struct sk_buff
* skb
, struct ip_options
* opt
,
41 __be32 daddr
, struct rtable
*rt
, int is_frag
)
43 unsigned char *iph
= skb_network_header(skb
);
45 memcpy(&(IPCB(skb
)->opt
), opt
, sizeof(struct ip_options
));
46 memcpy(iph
+sizeof(struct iphdr
), opt
->__data
, opt
->optlen
);
47 opt
= &(IPCB(skb
)->opt
);
50 memcpy(iph
+opt
->srr
+iph
[opt
->srr
+1]-4, &daddr
, 4);
54 ip_rt_get_source(iph
+opt
->rr
+iph
[opt
->rr
+2]-5, rt
);
56 ip_rt_get_source(iph
+opt
->ts
+iph
[opt
->ts
+2]-9, rt
);
57 if (opt
->ts_needtime
) {
61 midtime
= htonl((tv
.tv_sec
% 86400) * 1000 + tv
.tv_usec
/ 1000);
62 memcpy(iph
+opt
->ts
+iph
[opt
->ts
+2]-5, &midtime
, 4);
67 memset(iph
+opt
->rr
, IPOPT_NOP
, iph
[opt
->rr
+1]);
72 memset(iph
+opt
->ts
, IPOPT_NOP
, iph
[opt
->ts
+1]);
74 opt
->ts_needaddr
= opt
->ts_needtime
= 0;
79 * Provided (sopt, skb) points to received options,
80 * build in dopt compiled option set appropriate for answering.
81 * i.e. invert SRR option, copy anothers,
82 * and grab room in RR/TS options.
84 * NOTE: dopt cannot point to skb.
87 int ip_options_echo(struct ip_options
* dopt
, struct sk_buff
* skb
)
89 struct ip_options
*sopt
;
90 unsigned char *sptr
, *dptr
;
95 memset(dopt
, 0, sizeof(struct ip_options
));
97 sopt
= &(IPCB(skb
)->opt
);
99 if (sopt
->optlen
== 0) {
104 sptr
= skb_network_header(skb
);
107 daddr
= skb
->rtable
->rt_spec_dst
;
110 optlen
= sptr
[sopt
->rr
+1];
111 soffset
= sptr
[sopt
->rr
+2];
112 dopt
->rr
= dopt
->optlen
+ sizeof(struct iphdr
);
113 memcpy(dptr
, sptr
+sopt
->rr
, optlen
);
114 if (sopt
->rr_needaddr
&& soffset
<= optlen
) {
115 if (soffset
+ 3 > optlen
)
117 dptr
[2] = soffset
+ 4;
118 dopt
->rr_needaddr
= 1;
121 dopt
->optlen
+= optlen
;
124 optlen
= sptr
[sopt
->ts
+1];
125 soffset
= sptr
[sopt
->ts
+2];
126 dopt
->ts
= dopt
->optlen
+ sizeof(struct iphdr
);
127 memcpy(dptr
, sptr
+sopt
->ts
, optlen
);
128 if (soffset
<= optlen
) {
129 if (sopt
->ts_needaddr
) {
130 if (soffset
+ 3 > optlen
)
132 dopt
->ts_needaddr
= 1;
135 if (sopt
->ts_needtime
) {
136 if (soffset
+ 3 > optlen
)
138 if ((dptr
[3]&0xF) != IPOPT_TS_PRESPEC
) {
139 dopt
->ts_needtime
= 1;
142 dopt
->ts_needtime
= 0;
144 if (soffset
+ 8 <= optlen
) {
147 memcpy(&addr
, sptr
+soffset
-1, 4);
148 if (inet_addr_type(&init_net
, addr
) != RTN_LOCAL
) {
149 dopt
->ts_needtime
= 1;
158 dopt
->optlen
+= optlen
;
161 unsigned char * start
= sptr
+sopt
->srr
;
167 if (soffset
> optlen
)
168 soffset
= optlen
+ 1;
171 memcpy(&faddr
, &start
[soffset
-1], 4);
172 for (soffset
-=4, doffset
=4; soffset
> 3; soffset
-=4, doffset
+=4)
173 memcpy(&dptr
[doffset
-1], &start
[soffset
-1], 4);
175 * RFC1812 requires to fix illegal source routes.
177 if (memcmp(&ip_hdr(skb
)->saddr
,
178 &start
[soffset
+ 3], 4) == 0)
182 memcpy(&start
[doffset
-1], &daddr
, 4);
188 dopt
->srr
= dopt
->optlen
+ sizeof(struct iphdr
);
189 dopt
->optlen
+= doffset
+3;
190 dopt
->is_strictroute
= sopt
->is_strictroute
;
194 optlen
= sptr
[sopt
->cipso
+1];
195 dopt
->cipso
= dopt
->optlen
+sizeof(struct iphdr
);
196 memcpy(dptr
, sptr
+sopt
->cipso
, optlen
);
198 dopt
->optlen
+= optlen
;
200 while (dopt
->optlen
& 3) {
208 * Options "fragmenting", just fill options not
209 * allowed in fragments with NOOPs.
210 * Simple and stupid 8), but the most efficient way.
213 void ip_options_fragment(struct sk_buff
* skb
)
215 unsigned char *optptr
= skb_network_header(skb
) + sizeof(struct iphdr
);
216 struct ip_options
* opt
= &(IPCB(skb
)->opt
);
230 if (optlen
<2 || optlen
>l
)
232 if (!IPOPT_COPIED(*optptr
))
233 memset(optptr
, IPOPT_NOOP
, optlen
);
239 opt
->rr_needaddr
= 0;
240 opt
->ts_needaddr
= 0;
241 opt
->ts_needtime
= 0;
246 * Verify options and fill pointers in struct options.
247 * Caller should clear *opt, and set opt->data.
248 * If opt == NULL, then skb->data should point to IP header.
251 int ip_options_compile(struct ip_options
* opt
, struct sk_buff
* skb
)
255 unsigned char * optptr
;
257 unsigned char * pp_ptr
= NULL
;
258 struct rtable
*rt
= NULL
;
262 optptr
= (unsigned char *)&(ip_hdr(skb
)[1]);
264 optptr
= opt
->__data
;
265 iph
= optptr
- sizeof(struct iphdr
);
267 for (l
= opt
->optlen
; l
> 0; ) {
270 for (optptr
++, l
--; l
>0; optptr
++, l
--) {
271 if (*optptr
!= IPOPT_END
) {
283 if (optlen
<2 || optlen
>l
) {
298 /* NB: cf RFC-1812 5.2.4.1 */
304 if (optptr
[2] != 4 || optlen
< 7 || ((optlen
-3) & 3)) {
308 memcpy(&opt
->faddr
, &optptr
[3], 4);
310 memmove(&optptr
[3], &optptr
[7], optlen
-7);
312 opt
->is_strictroute
= (optptr
[0] == IPOPT_SSRR
);
313 opt
->srr
= optptr
- iph
;
328 if (optptr
[2] <= optlen
) {
329 if (optptr
[2]+3 > optlen
) {
334 memcpy(&optptr
[optptr
[2]-1], &rt
->rt_spec_dst
, 4);
338 opt
->rr_needaddr
= 1;
340 opt
->rr
= optptr
- iph
;
342 case IPOPT_TIMESTAMP
:
355 if (optptr
[2] <= optlen
) {
356 __be32
*timeptr
= NULL
;
357 if (optptr
[2]+3 > optptr
[1]) {
361 switch (optptr
[3]&0xF) {
362 case IPOPT_TS_TSONLY
:
363 opt
->ts
= optptr
- iph
;
365 timeptr
= (__be32
*)&optptr
[optptr
[2]-1];
366 opt
->ts_needtime
= 1;
369 case IPOPT_TS_TSANDADDR
:
370 if (optptr
[2]+7 > optptr
[1]) {
374 opt
->ts
= optptr
- iph
;
376 memcpy(&optptr
[optptr
[2]-1], &rt
->rt_spec_dst
, 4);
377 timeptr
= (__be32
*)&optptr
[optptr
[2]+3];
379 opt
->ts_needaddr
= 1;
380 opt
->ts_needtime
= 1;
383 case IPOPT_TS_PRESPEC
:
384 if (optptr
[2]+7 > optptr
[1]) {
388 opt
->ts
= optptr
- iph
;
391 memcpy(&addr
, &optptr
[optptr
[2]-1], 4);
392 if (inet_addr_type(&init_net
, addr
) == RTN_UNICAST
)
395 timeptr
= (__be32
*)&optptr
[optptr
[2]+3];
397 opt
->ts_needtime
= 1;
401 if (!skb
&& !capable(CAP_NET_RAW
)) {
410 do_gettimeofday(&tv
);
411 midtime
= htonl((tv
.tv_sec
% 86400) * 1000 + tv
.tv_usec
/ 1000);
412 memcpy(timeptr
, &midtime
, sizeof(__be32
));
416 unsigned overflow
= optptr
[3]>>4;
417 if (overflow
== 15) {
421 opt
->ts
= optptr
- iph
;
423 optptr
[3] = (optptr
[3]&0xF)|((overflow
+1)<<4);
433 if (optptr
[2] == 0 && optptr
[3] == 0)
434 opt
->router_alert
= optptr
- iph
;
437 if ((!skb
&& !capable(CAP_NET_RAW
)) || opt
->cipso
) {
441 opt
->cipso
= optptr
- iph
;
442 if (cipso_v4_validate(&optptr
)) {
450 if (!skb
&& !capable(CAP_NET_RAW
)) {
466 icmp_send(skb
, ICMP_PARAMETERPROB
, 0, htonl((pp_ptr
-iph
)<<24));
473 * Undo all the changes done by ip_options_compile().
476 void ip_options_undo(struct ip_options
* opt
)
479 unsigned char * optptr
= opt
->__data
+opt
->srr
-sizeof(struct iphdr
);
480 memmove(optptr
+7, optptr
+3, optptr
[1]-7);
481 memcpy(optptr
+3, &opt
->faddr
, 4);
483 if (opt
->rr_needaddr
) {
484 unsigned char * optptr
= opt
->__data
+opt
->rr
-sizeof(struct iphdr
);
486 memset(&optptr
[optptr
[2]-1], 0, 4);
489 unsigned char * optptr
= opt
->__data
+opt
->ts
-sizeof(struct iphdr
);
490 if (opt
->ts_needtime
) {
492 memset(&optptr
[optptr
[2]-1], 0, 4);
493 if ((optptr
[3]&0xF) == IPOPT_TS_PRESPEC
)
496 if (opt
->ts_needaddr
) {
498 memset(&optptr
[optptr
[2]-1], 0, 4);
503 static struct ip_options
*ip_options_get_alloc(const int optlen
)
505 return kzalloc(sizeof(struct ip_options
) + ((optlen
+ 3) & ~3),
509 static int ip_options_get_finish(struct ip_options
**optp
,
510 struct ip_options
*opt
, int optlen
)
513 opt
->__data
[optlen
++] = IPOPT_END
;
514 opt
->optlen
= optlen
;
515 if (optlen
&& ip_options_compile(opt
, NULL
)) {
524 int ip_options_get_from_user(struct ip_options
**optp
, unsigned char __user
*data
, int optlen
)
526 struct ip_options
*opt
= ip_options_get_alloc(optlen
);
530 if (optlen
&& copy_from_user(opt
->__data
, data
, optlen
)) {
534 return ip_options_get_finish(optp
, opt
, optlen
);
537 int ip_options_get(struct ip_options
**optp
, unsigned char *data
, int optlen
)
539 struct ip_options
*opt
= ip_options_get_alloc(optlen
);
544 memcpy(opt
->__data
, data
, optlen
);
545 return ip_options_get_finish(optp
, opt
, optlen
);
548 void ip_forward_options(struct sk_buff
*skb
)
550 struct ip_options
* opt
= &(IPCB(skb
)->opt
);
551 unsigned char * optptr
;
552 struct rtable
*rt
= skb
->rtable
;
553 unsigned char *raw
= skb_network_header(skb
);
555 if (opt
->rr_needaddr
) {
556 optptr
= (unsigned char *)raw
+ opt
->rr
;
557 ip_rt_get_source(&optptr
[optptr
[2]-5], rt
);
560 if (opt
->srr_is_hit
) {
561 int srrptr
, srrspace
;
563 optptr
= raw
+ opt
->srr
;
565 for ( srrptr
=optptr
[2], srrspace
= optptr
[1];
569 if (srrptr
+ 3 > srrspace
)
571 if (memcmp(&rt
->rt_dst
, &optptr
[srrptr
-1], 4) == 0)
574 if (srrptr
+ 3 <= srrspace
) {
576 ip_rt_get_source(&optptr
[srrptr
-1], rt
);
577 ip_hdr(skb
)->daddr
= rt
->rt_dst
;
578 optptr
[2] = srrptr
+4;
579 } else if (net_ratelimit())
580 printk(KERN_CRIT
"ip_forward(): Argh! Destination lost!\n");
581 if (opt
->ts_needaddr
) {
582 optptr
= raw
+ opt
->ts
;
583 ip_rt_get_source(&optptr
[optptr
[2]-9], rt
);
587 if (opt
->is_changed
) {
589 ip_send_check(ip_hdr(skb
));
593 int ip_options_rcv_srr(struct sk_buff
*skb
)
595 struct ip_options
*opt
= &(IPCB(skb
)->opt
);
596 int srrspace
, srrptr
;
598 struct iphdr
*iph
= ip_hdr(skb
);
599 unsigned char *optptr
= skb_network_header(skb
) + opt
->srr
;
600 struct rtable
*rt
= skb
->rtable
;
607 if (skb
->pkt_type
!= PACKET_HOST
)
609 if (rt
->rt_type
== RTN_UNICAST
) {
610 if (!opt
->is_strictroute
)
612 icmp_send(skb
, ICMP_PARAMETERPROB
, 0, htonl(16<<24));
615 if (rt
->rt_type
!= RTN_LOCAL
)
618 for (srrptr
=optptr
[2], srrspace
= optptr
[1]; srrptr
<= srrspace
; srrptr
+= 4) {
619 if (srrptr
+ 3 > srrspace
) {
620 icmp_send(skb
, ICMP_PARAMETERPROB
, 0, htonl((opt
->srr
+2)<<24));
623 memcpy(&nexthop
, &optptr
[srrptr
-1], 4);
627 err
= ip_route_input(skb
, nexthop
, iph
->saddr
, iph
->tos
, skb
->dev
);
629 if (err
|| (rt2
->rt_type
!= RTN_UNICAST
&& rt2
->rt_type
!= RTN_LOCAL
)) {
635 if (rt2
->rt_type
!= RTN_LOCAL
)
637 /* Superfast 8) loopback forward */
638 memcpy(&iph
->daddr
, &optptr
[srrptr
-1], 4);
641 if (srrptr
<= srrspace
) {
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