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 * Authors: A.N.Kuznetsov
12 #define pr_fmt(fmt) "IPv4: " fmt
14 #include <linux/capability.h>
15 #include <linux/module.h>
16 #include <linux/slab.h>
17 #include <linux/types.h>
18 #include <asm/uaccess.h>
19 #include <asm/unaligned.h>
20 #include <linux/skbuff.h>
22 #include <linux/icmp.h>
23 #include <linux/netdevice.h>
24 #include <linux/rtnetlink.h>
28 #include <net/route.h>
29 #include <net/cipso_ipv4.h>
32 * Write options to IP header, record destination address to
33 * source route option, address of outgoing interface
34 * (we should already know it, so that this function is allowed be
35 * called only after routing decision) and timestamp,
36 * if we originate this datagram.
38 * daddr is real destination address, next hop is recorded in IP header.
39 * saddr is address of outgoing interface.
42 void ip_options_build(struct sk_buff
*skb
, struct ip_options
*opt
,
43 __be32 daddr
, struct rtable
*rt
, int is_frag
)
45 unsigned char *iph
= skb_network_header(skb
);
47 memcpy(&(IPCB(skb
)->opt
), opt
, sizeof(struct ip_options
));
48 memcpy(iph
+sizeof(struct iphdr
), opt
->__data
, opt
->optlen
);
49 opt
= &(IPCB(skb
)->opt
);
52 memcpy(iph
+opt
->srr
+iph
[opt
->srr
+1]-4, &daddr
, 4);
56 ip_rt_get_source(iph
+opt
->rr
+iph
[opt
->rr
+2]-5, skb
, rt
);
58 ip_rt_get_source(iph
+opt
->ts
+iph
[opt
->ts
+2]-9, skb
, rt
);
59 if (opt
->ts_needtime
) {
63 midtime
= htonl((tv
.tv_sec
% 86400) * MSEC_PER_SEC
+ tv
.tv_nsec
/ NSEC_PER_MSEC
);
64 memcpy(iph
+opt
->ts
+iph
[opt
->ts
+2]-5, &midtime
, 4);
69 memset(iph
+opt
->rr
, IPOPT_NOP
, iph
[opt
->rr
+1]);
74 memset(iph
+opt
->ts
, IPOPT_NOP
, iph
[opt
->ts
+1]);
76 opt
->ts_needaddr
= opt
->ts_needtime
= 0;
81 * Provided (sopt, skb) points to received options,
82 * build in dopt compiled option set appropriate for answering.
83 * i.e. invert SRR option, copy anothers,
84 * and grab room in RR/TS options.
86 * NOTE: dopt cannot point to skb.
89 int ip_options_echo(struct ip_options
*dopt
, struct sk_buff
*skb
)
91 const struct ip_options
*sopt
;
92 unsigned char *sptr
, *dptr
;
97 memset(dopt
, 0, sizeof(struct ip_options
));
99 sopt
= &(IPCB(skb
)->opt
);
101 if (sopt
->optlen
== 0)
104 sptr
= skb_network_header(skb
);
107 daddr
= skb_rtable(skb
)->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
+ 7 <= optlen
) {
147 memcpy(&addr
, dptr
+soffset
-1, 4);
148 if (inet_addr_type(dev_net(skb_dst(skb
)->dev
), addr
) != RTN_UNICAST
) {
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;
245 * Verify options and fill pointers in struct options.
246 * Caller should clear *opt, and set opt->data.
247 * If opt == NULL, then skb->data should point to IP header.
250 int ip_options_compile(struct net
*net
,
251 struct ip_options
*opt
, struct sk_buff
*skb
)
255 unsigned char *optptr
;
257 unsigned char *pp_ptr
= NULL
;
258 struct rtable
*rt
= NULL
;
261 rt
= skb_rtable(skb
);
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 unsigned char *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
= &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
= &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(net
, addr
) == RTN_UNICAST
)
395 timeptr
= &optptr
[optptr
[2]+3];
397 opt
->ts_needtime
= 1;
401 if (!skb
&& !capable(CAP_NET_RAW
)) {
411 midtime
= (tv
.tv_sec
% 86400) * MSEC_PER_SEC
+ tv
.tv_nsec
/ NSEC_PER_MSEC
;
412 put_unaligned_be32(midtime
, timeptr
);
416 unsigned int 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(skb
, &optptr
)) {
450 if (!skb
&& !capable(CAP_NET_RAW
)) {
466 icmp_send(skb
, ICMP_PARAMETERPROB
, 0, htonl((pp_ptr
-iph
)<<24));
470 EXPORT_SYMBOL(ip_options_compile
);
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_rcu
*ip_options_get_alloc(const int optlen
)
505 return kzalloc(sizeof(struct ip_options_rcu
) + ((optlen
+ 3) & ~3),
509 static int ip_options_get_finish(struct net
*net
, struct ip_options_rcu
**optp
,
510 struct ip_options_rcu
*opt
, int optlen
)
513 opt
->opt
.__data
[optlen
++] = IPOPT_END
;
514 opt
->opt
.optlen
= optlen
;
515 if (optlen
&& ip_options_compile(net
, &opt
->opt
, NULL
)) {
524 int ip_options_get_from_user(struct net
*net
, struct ip_options_rcu
**optp
,
525 unsigned char __user
*data
, int optlen
)
527 struct ip_options_rcu
*opt
= ip_options_get_alloc(optlen
);
531 if (optlen
&& copy_from_user(opt
->opt
.__data
, data
, optlen
)) {
535 return ip_options_get_finish(net
, optp
, opt
, optlen
);
538 int ip_options_get(struct net
*net
, struct ip_options_rcu
**optp
,
539 unsigned char *data
, int optlen
)
541 struct ip_options_rcu
*opt
= ip_options_get_alloc(optlen
);
546 memcpy(opt
->opt
.__data
, data
, optlen
);
547 return ip_options_get_finish(net
, optp
, opt
, optlen
);
550 void ip_forward_options(struct sk_buff
*skb
)
552 struct ip_options
*opt
= &(IPCB(skb
)->opt
);
553 unsigned char *optptr
;
554 struct rtable
*rt
= skb_rtable(skb
);
555 unsigned char *raw
= skb_network_header(skb
);
557 if (opt
->rr_needaddr
) {
558 optptr
= (unsigned char *)raw
+ opt
->rr
;
559 ip_rt_get_source(&optptr
[optptr
[2]-5], skb
, rt
);
562 if (opt
->srr_is_hit
) {
563 int srrptr
, srrspace
;
565 optptr
= raw
+ opt
->srr
;
567 for ( srrptr
=optptr
[2], srrspace
= optptr
[1];
571 if (srrptr
+ 3 > srrspace
)
573 if (memcmp(&opt
->nexthop
, &optptr
[srrptr
-1], 4) == 0)
576 if (srrptr
+ 3 <= srrspace
) {
578 ip_hdr(skb
)->daddr
= opt
->nexthop
;
579 ip_rt_get_source(&optptr
[srrptr
-1], skb
, rt
);
580 optptr
[2] = srrptr
+4;
581 } else if (net_ratelimit())
582 pr_crit("%s(): Argh! Destination lost!\n", __func__
);
583 if (opt
->ts_needaddr
) {
584 optptr
= raw
+ opt
->ts
;
585 ip_rt_get_source(&optptr
[optptr
[2]-9], skb
, rt
);
589 if (opt
->is_changed
) {
591 ip_send_check(ip_hdr(skb
));
595 int ip_options_rcv_srr(struct sk_buff
*skb
)
597 struct ip_options
*opt
= &(IPCB(skb
)->opt
);
598 int srrspace
, srrptr
;
600 struct iphdr
*iph
= ip_hdr(skb
);
601 unsigned char *optptr
= skb_network_header(skb
) + opt
->srr
;
602 struct rtable
*rt
= skb_rtable(skb
);
604 unsigned long orefdst
;
610 if (skb
->pkt_type
!= PACKET_HOST
)
612 if (rt
->rt_type
== RTN_UNICAST
) {
613 if (!opt
->is_strictroute
)
615 icmp_send(skb
, ICMP_PARAMETERPROB
, 0, htonl(16<<24));
618 if (rt
->rt_type
!= RTN_LOCAL
)
621 for (srrptr
=optptr
[2], srrspace
= optptr
[1]; srrptr
<= srrspace
; srrptr
+= 4) {
622 if (srrptr
+ 3 > srrspace
) {
623 icmp_send(skb
, ICMP_PARAMETERPROB
, 0, htonl((opt
->srr
+2)<<24));
626 memcpy(&nexthop
, &optptr
[srrptr
-1], 4);
628 orefdst
= skb
->_skb_refdst
;
629 skb_dst_set(skb
, NULL
);
630 err
= ip_route_input(skb
, nexthop
, iph
->saddr
, iph
->tos
, skb
->dev
);
631 rt2
= skb_rtable(skb
);
632 if (err
|| (rt2
->rt_type
!= RTN_UNICAST
&& rt2
->rt_type
!= RTN_LOCAL
)) {
634 skb
->_skb_refdst
= orefdst
;
637 refdst_drop(orefdst
);
638 if (rt2
->rt_type
!= RTN_LOCAL
)
640 /* Superfast 8) loopback forward */
641 iph
->daddr
= nexthop
;
644 if (srrptr
<= srrspace
) {
646 opt
->nexthop
= nexthop
;
651 EXPORT_SYMBOL(ip_options_rcv_srr
);