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git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - net/ipv4/ip_options.c
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) * MSEC_PER_SEC
+ tv
.tv_nsec
/ NSEC_PER_MSEC
);
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(dev_net(skb
->dst
->dev
), 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 net
*net
,
252 struct ip_options
* opt
, struct sk_buff
* skb
)
256 unsigned char * optptr
;
258 unsigned char * pp_ptr
= NULL
;
259 struct rtable
*rt
= NULL
;
263 optptr
= (unsigned char *)&(ip_hdr(skb
)[1]);
265 optptr
= opt
->__data
;
266 iph
= optptr
- sizeof(struct iphdr
);
268 for (l
= opt
->optlen
; l
> 0; ) {
271 for (optptr
++, l
--; l
>0; optptr
++, l
--) {
272 if (*optptr
!= IPOPT_END
) {
284 if (optlen
<2 || optlen
>l
) {
299 /* NB: cf RFC-1812 5.2.4.1 */
305 if (optptr
[2] != 4 || optlen
< 7 || ((optlen
-3) & 3)) {
309 memcpy(&opt
->faddr
, &optptr
[3], 4);
311 memmove(&optptr
[3], &optptr
[7], optlen
-7);
313 opt
->is_strictroute
= (optptr
[0] == IPOPT_SSRR
);
314 opt
->srr
= optptr
- iph
;
329 if (optptr
[2] <= optlen
) {
330 if (optptr
[2]+3 > optlen
) {
335 memcpy(&optptr
[optptr
[2]-1], &rt
->rt_spec_dst
, 4);
339 opt
->rr_needaddr
= 1;
341 opt
->rr
= optptr
- iph
;
343 case IPOPT_TIMESTAMP
:
356 if (optptr
[2] <= optlen
) {
357 __be32
*timeptr
= NULL
;
358 if (optptr
[2]+3 > optptr
[1]) {
362 switch (optptr
[3]&0xF) {
363 case IPOPT_TS_TSONLY
:
364 opt
->ts
= optptr
- iph
;
366 timeptr
= (__be32
*)&optptr
[optptr
[2]-1];
367 opt
->ts_needtime
= 1;
370 case IPOPT_TS_TSANDADDR
:
371 if (optptr
[2]+7 > optptr
[1]) {
375 opt
->ts
= optptr
- iph
;
377 memcpy(&optptr
[optptr
[2]-1], &rt
->rt_spec_dst
, 4);
378 timeptr
= (__be32
*)&optptr
[optptr
[2]+3];
380 opt
->ts_needaddr
= 1;
381 opt
->ts_needtime
= 1;
384 case IPOPT_TS_PRESPEC
:
385 if (optptr
[2]+7 > optptr
[1]) {
389 opt
->ts
= optptr
- iph
;
392 memcpy(&addr
, &optptr
[optptr
[2]-1], 4);
393 if (inet_addr_type(net
, addr
) == RTN_UNICAST
)
396 timeptr
= (__be32
*)&optptr
[optptr
[2]+3];
398 opt
->ts_needtime
= 1;
402 if (!skb
&& !capable(CAP_NET_RAW
)) {
412 midtime
= htonl((tv
.tv_sec
% 86400) * MSEC_PER_SEC
+ tv
.tv_nsec
/ NSEC_PER_MSEC
);
413 memcpy(timeptr
, &midtime
, sizeof(__be32
));
417 unsigned overflow
= optptr
[3]>>4;
418 if (overflow
== 15) {
422 opt
->ts
= optptr
- iph
;
424 optptr
[3] = (optptr
[3]&0xF)|((overflow
+1)<<4);
434 if (optptr
[2] == 0 && optptr
[3] == 0)
435 opt
->router_alert
= optptr
- iph
;
438 if ((!skb
&& !capable(CAP_NET_RAW
)) || opt
->cipso
) {
442 opt
->cipso
= optptr
- iph
;
443 if (cipso_v4_validate(&optptr
)) {
451 if (!skb
&& !capable(CAP_NET_RAW
)) {
467 icmp_send(skb
, ICMP_PARAMETERPROB
, 0, htonl((pp_ptr
-iph
)<<24));
474 * Undo all the changes done by ip_options_compile().
477 void ip_options_undo(struct ip_options
* opt
)
480 unsigned char * optptr
= opt
->__data
+opt
->srr
-sizeof(struct iphdr
);
481 memmove(optptr
+7, optptr
+3, optptr
[1]-7);
482 memcpy(optptr
+3, &opt
->faddr
, 4);
484 if (opt
->rr_needaddr
) {
485 unsigned char * optptr
= opt
->__data
+opt
->rr
-sizeof(struct iphdr
);
487 memset(&optptr
[optptr
[2]-1], 0, 4);
490 unsigned char * optptr
= opt
->__data
+opt
->ts
-sizeof(struct iphdr
);
491 if (opt
->ts_needtime
) {
493 memset(&optptr
[optptr
[2]-1], 0, 4);
494 if ((optptr
[3]&0xF) == IPOPT_TS_PRESPEC
)
497 if (opt
->ts_needaddr
) {
499 memset(&optptr
[optptr
[2]-1], 0, 4);
504 static struct ip_options
*ip_options_get_alloc(const int optlen
)
506 return kzalloc(sizeof(struct ip_options
) + ((optlen
+ 3) & ~3),
510 static int ip_options_get_finish(struct net
*net
, struct ip_options
**optp
,
511 struct ip_options
*opt
, int optlen
)
514 opt
->__data
[optlen
++] = IPOPT_END
;
515 opt
->optlen
= optlen
;
516 if (optlen
&& ip_options_compile(net
, opt
, NULL
)) {
525 int ip_options_get_from_user(struct net
*net
, struct ip_options
**optp
,
526 unsigned char __user
*data
, int optlen
)
528 struct ip_options
*opt
= ip_options_get_alloc(optlen
);
532 if (optlen
&& copy_from_user(opt
->__data
, data
, optlen
)) {
536 return ip_options_get_finish(net
, optp
, opt
, optlen
);
539 int ip_options_get(struct net
*net
, struct ip_options
**optp
,
540 unsigned char *data
, int optlen
)
542 struct ip_options
*opt
= ip_options_get_alloc(optlen
);
547 memcpy(opt
->__data
, data
, optlen
);
548 return ip_options_get_finish(net
, optp
, opt
, optlen
);
551 void ip_forward_options(struct sk_buff
*skb
)
553 struct ip_options
* opt
= &(IPCB(skb
)->opt
);
554 unsigned char * optptr
;
555 struct rtable
*rt
= skb
->rtable
;
556 unsigned char *raw
= skb_network_header(skb
);
558 if (opt
->rr_needaddr
) {
559 optptr
= (unsigned char *)raw
+ opt
->rr
;
560 ip_rt_get_source(&optptr
[optptr
[2]-5], rt
);
563 if (opt
->srr_is_hit
) {
564 int srrptr
, srrspace
;
566 optptr
= raw
+ opt
->srr
;
568 for ( srrptr
=optptr
[2], srrspace
= optptr
[1];
572 if (srrptr
+ 3 > srrspace
)
574 if (memcmp(&rt
->rt_dst
, &optptr
[srrptr
-1], 4) == 0)
577 if (srrptr
+ 3 <= srrspace
) {
579 ip_rt_get_source(&optptr
[srrptr
-1], rt
);
580 ip_hdr(skb
)->daddr
= rt
->rt_dst
;
581 optptr
[2] = srrptr
+4;
582 } else if (net_ratelimit())
583 printk(KERN_CRIT
"ip_forward(): Argh! Destination lost!\n");
584 if (opt
->ts_needaddr
) {
585 optptr
= raw
+ opt
->ts
;
586 ip_rt_get_source(&optptr
[optptr
[2]-9], rt
);
590 if (opt
->is_changed
) {
592 ip_send_check(ip_hdr(skb
));
596 int ip_options_rcv_srr(struct sk_buff
*skb
)
598 struct ip_options
*opt
= &(IPCB(skb
)->opt
);
599 int srrspace
, srrptr
;
601 struct iphdr
*iph
= ip_hdr(skb
);
602 unsigned char *optptr
= skb_network_header(skb
) + opt
->srr
;
603 struct rtable
*rt
= skb
->rtable
;
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);
630 err
= ip_route_input(skb
, nexthop
, iph
->saddr
, iph
->tos
, skb
->dev
);
632 if (err
|| (rt2
->rt_type
!= RTN_UNICAST
&& rt2
->rt_type
!= RTN_LOCAL
)) {
638 if (rt2
->rt_type
!= RTN_LOCAL
)
640 /* Superfast 8) loopback forward */
641 memcpy(&iph
->daddr
, &optptr
[srrptr
-1], 4);
644 if (srrptr
<= srrspace
) {