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git.proxmox.com Git - mirror_ubuntu-jammy-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>
29 * Write options to IP header, record destination address to
30 * source route option, address of outgoing interface
31 * (we should already know it, so that this function is allowed be
32 * called only after routing decision) and timestamp,
33 * if we originate this datagram.
35 * daddr is real destination address, next hop is recorded in IP header.
36 * saddr is address of outgoing interface.
39 void ip_options_build(struct sk_buff
* skb
, struct ip_options
* opt
,
40 u32 daddr
, struct rtable
*rt
, int is_frag
)
42 unsigned char * iph
= skb
->nh
.raw
;
44 memcpy(&(IPCB(skb
)->opt
), opt
, sizeof(struct ip_options
));
45 memcpy(iph
+sizeof(struct iphdr
), opt
->__data
, opt
->optlen
);
46 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
));
99 sopt
= &(IPCB(skb
)->opt
);
101 if (sopt
->optlen
== 0) {
110 daddr
= ((struct rtable
*)skb
->dst
)->rt_spec_dst
;
112 daddr
= skb
->nh
.iph
->daddr
;
115 optlen
= sptr
[sopt
->rr
+1];
116 soffset
= sptr
[sopt
->rr
+2];
117 dopt
->rr
= dopt
->optlen
+ sizeof(struct iphdr
);
118 memcpy(dptr
, sptr
+sopt
->rr
, optlen
);
119 if (sopt
->rr_needaddr
&& soffset
<= optlen
) {
120 if (soffset
+ 3 > optlen
)
122 dptr
[2] = soffset
+ 4;
123 dopt
->rr_needaddr
= 1;
126 dopt
->optlen
+= optlen
;
129 optlen
= sptr
[sopt
->ts
+1];
130 soffset
= sptr
[sopt
->ts
+2];
131 dopt
->ts
= dopt
->optlen
+ sizeof(struct iphdr
);
132 memcpy(dptr
, sptr
+sopt
->ts
, optlen
);
133 if (soffset
<= optlen
) {
134 if (sopt
->ts_needaddr
) {
135 if (soffset
+ 3 > optlen
)
137 dopt
->ts_needaddr
= 1;
140 if (sopt
->ts_needtime
) {
141 if (soffset
+ 3 > optlen
)
143 if ((dptr
[3]&0xF) != IPOPT_TS_PRESPEC
) {
144 dopt
->ts_needtime
= 1;
147 dopt
->ts_needtime
= 0;
149 if (soffset
+ 8 <= optlen
) {
152 memcpy(&addr
, sptr
+soffset
-1, 4);
153 if (inet_addr_type(addr
) != RTN_LOCAL
) {
154 dopt
->ts_needtime
= 1;
163 dopt
->optlen
+= optlen
;
166 unsigned char * start
= sptr
+sopt
->srr
;
172 if (soffset
> optlen
)
173 soffset
= optlen
+ 1;
176 memcpy(&faddr
, &start
[soffset
-1], 4);
177 for (soffset
-=4, doffset
=4; soffset
> 3; soffset
-=4, doffset
+=4)
178 memcpy(&dptr
[doffset
-1], &start
[soffset
-1], 4);
180 * RFC1812 requires to fix illegal source routes.
182 if (memcmp(&skb
->nh
.iph
->saddr
, &start
[soffset
+3], 4) == 0)
186 memcpy(&start
[doffset
-1], &daddr
, 4);
192 dopt
->srr
= dopt
->optlen
+ sizeof(struct iphdr
);
193 dopt
->optlen
+= doffset
+3;
194 dopt
->is_strictroute
= sopt
->is_strictroute
;
197 while (dopt
->optlen
& 3) {
205 * Options "fragmenting", just fill options not
206 * allowed in fragments with NOOPs.
207 * Simple and stupid 8), but the most efficient way.
210 void ip_options_fragment(struct sk_buff
* skb
)
212 unsigned char * optptr
= skb
->nh
.raw
;
213 struct ip_options
* opt
= &(IPCB(skb
)->opt
);
227 if (optlen
<2 || optlen
>l
)
229 if (!IPOPT_COPIED(*optptr
))
230 memset(optptr
, IPOPT_NOOP
, optlen
);
236 opt
->rr_needaddr
= 0;
237 opt
->ts_needaddr
= 0;
238 opt
->ts_needtime
= 0;
243 * Verify options and fill pointers in struct options.
244 * Caller should clear *opt, and set opt->data.
245 * If opt == NULL, then skb->data should point to IP header.
248 int ip_options_compile(struct ip_options
* opt
, struct sk_buff
* skb
)
252 unsigned char * optptr
;
254 unsigned char * pp_ptr
= NULL
;
255 struct rtable
*rt
= skb
? (struct rtable
*)skb
->dst
: NULL
;
258 opt
= &(IPCB(skb
)->opt
);
259 memset(opt
, 0, sizeof(struct ip_options
));
261 opt
->optlen
= ((struct iphdr
*)iph
)->ihl
*4 - sizeof(struct iphdr
);
262 optptr
= iph
+ sizeof(struct iphdr
);
265 optptr
= opt
->is_data
? opt
->__data
: (unsigned char*)&(skb
->nh
.iph
[1]);
266 iph
= optptr
- sizeof(struct iphdr
);
269 for (l
= opt
->optlen
; l
> 0; ) {
272 for (optptr
++, l
--; l
>0; optptr
++, l
--) {
273 if (*optptr
!= IPOPT_END
) {
285 if (optlen
<2 || optlen
>l
) {
300 /* NB: cf RFC-1812 5.2.4.1 */
306 if (optptr
[2] != 4 || optlen
< 7 || ((optlen
-3) & 3)) {
310 memcpy(&opt
->faddr
, &optptr
[3], 4);
312 memmove(&optptr
[3], &optptr
[7], optlen
-7);
314 opt
->is_strictroute
= (optptr
[0] == IPOPT_SSRR
);
315 opt
->srr
= optptr
- iph
;
330 if (optptr
[2] <= optlen
) {
331 if (optptr
[2]+3 > optlen
) {
336 memcpy(&optptr
[optptr
[2]-1], &rt
->rt_spec_dst
, 4);
340 opt
->rr_needaddr
= 1;
342 opt
->rr
= optptr
- iph
;
344 case IPOPT_TIMESTAMP
:
357 if (optptr
[2] <= optlen
) {
358 __u32
* timeptr
= NULL
;
359 if (optptr
[2]+3 > optptr
[1]) {
363 switch (optptr
[3]&0xF) {
364 case IPOPT_TS_TSONLY
:
365 opt
->ts
= optptr
- iph
;
367 timeptr
= (__u32
*)&optptr
[optptr
[2]-1];
368 opt
->ts_needtime
= 1;
371 case IPOPT_TS_TSANDADDR
:
372 if (optptr
[2]+7 > optptr
[1]) {
376 opt
->ts
= optptr
- iph
;
378 memcpy(&optptr
[optptr
[2]-1], &rt
->rt_spec_dst
, 4);
379 timeptr
= (__u32
*)&optptr
[optptr
[2]+3];
381 opt
->ts_needaddr
= 1;
382 opt
->ts_needtime
= 1;
385 case IPOPT_TS_PRESPEC
:
386 if (optptr
[2]+7 > optptr
[1]) {
390 opt
->ts
= optptr
- iph
;
393 memcpy(&addr
, &optptr
[optptr
[2]-1], 4);
394 if (inet_addr_type(addr
) == RTN_UNICAST
)
397 timeptr
= (__u32
*)&optptr
[optptr
[2]+3];
399 opt
->ts_needtime
= 1;
403 if (!skb
&& !capable(CAP_NET_RAW
)) {
412 do_gettimeofday(&tv
);
413 midtime
= htonl((tv
.tv_sec
% 86400) * 1000 + tv
.tv_usec
/ 1000);
414 memcpy(timeptr
, &midtime
, sizeof(__u32
));
418 unsigned overflow
= optptr
[3]>>4;
419 if (overflow
== 15) {
423 opt
->ts
= optptr
- iph
;
425 optptr
[3] = (optptr
[3]&0xF)|((overflow
+1)<<4);
435 if (optptr
[2] == 0 && optptr
[3] == 0)
436 opt
->router_alert
= optptr
- iph
;
441 if (!skb
&& !capable(CAP_NET_RAW
)) {
457 icmp_send(skb
, ICMP_PARAMETERPROB
, 0, htonl((pp_ptr
-iph
)<<24));
464 * Undo all the changes done by ip_options_compile().
467 void ip_options_undo(struct ip_options
* opt
)
470 unsigned char * optptr
= opt
->__data
+opt
->srr
-sizeof(struct iphdr
);
471 memmove(optptr
+7, optptr
+3, optptr
[1]-7);
472 memcpy(optptr
+3, &opt
->faddr
, 4);
474 if (opt
->rr_needaddr
) {
475 unsigned char * optptr
= opt
->__data
+opt
->rr
-sizeof(struct iphdr
);
477 memset(&optptr
[optptr
[2]-1], 0, 4);
480 unsigned char * optptr
= opt
->__data
+opt
->ts
-sizeof(struct iphdr
);
481 if (opt
->ts_needtime
) {
483 memset(&optptr
[optptr
[2]-1], 0, 4);
484 if ((optptr
[3]&0xF) == IPOPT_TS_PRESPEC
)
487 if (opt
->ts_needaddr
) {
489 memset(&optptr
[optptr
[2]-1], 0, 4);
494 static struct ip_options
*ip_options_get_alloc(const int optlen
)
496 struct ip_options
*opt
= kmalloc(sizeof(*opt
) + ((optlen
+ 3) & ~3),
499 memset(opt
, 0, sizeof(*opt
));
503 static int ip_options_get_finish(struct ip_options
**optp
,
504 struct ip_options
*opt
, int optlen
)
507 opt
->__data
[optlen
++] = IPOPT_END
;
508 opt
->optlen
= optlen
;
510 opt
->is_setbyuser
= 1;
511 if (optlen
&& ip_options_compile(opt
, NULL
)) {
520 int ip_options_get_from_user(struct ip_options
**optp
, unsigned char __user
*data
, int optlen
)
522 struct ip_options
*opt
= ip_options_get_alloc(optlen
);
526 if (optlen
&& copy_from_user(opt
->__data
, data
, optlen
)) {
530 return ip_options_get_finish(optp
, opt
, optlen
);
533 int ip_options_get(struct ip_options
**optp
, unsigned char *data
, int optlen
)
535 struct ip_options
*opt
= ip_options_get_alloc(optlen
);
540 memcpy(opt
->__data
, data
, optlen
);
541 return ip_options_get_finish(optp
, opt
, optlen
);
544 void ip_forward_options(struct sk_buff
*skb
)
546 struct ip_options
* opt
= &(IPCB(skb
)->opt
);
547 unsigned char * optptr
;
548 struct rtable
*rt
= (struct rtable
*)skb
->dst
;
549 unsigned char *raw
= skb
->nh
.raw
;
551 if (opt
->rr_needaddr
) {
552 optptr
= (unsigned char *)raw
+ opt
->rr
;
553 ip_rt_get_source(&optptr
[optptr
[2]-5], rt
);
556 if (opt
->srr_is_hit
) {
557 int srrptr
, srrspace
;
559 optptr
= raw
+ opt
->srr
;
561 for ( srrptr
=optptr
[2], srrspace
= optptr
[1];
565 if (srrptr
+ 3 > srrspace
)
567 if (memcmp(&rt
->rt_dst
, &optptr
[srrptr
-1], 4) == 0)
570 if (srrptr
+ 3 <= srrspace
) {
572 ip_rt_get_source(&optptr
[srrptr
-1], rt
);
573 skb
->nh
.iph
->daddr
= rt
->rt_dst
;
574 optptr
[2] = srrptr
+4;
575 } else if (net_ratelimit())
576 printk(KERN_CRIT
"ip_forward(): Argh! Destination lost!\n");
577 if (opt
->ts_needaddr
) {
578 optptr
= raw
+ opt
->ts
;
579 ip_rt_get_source(&optptr
[optptr
[2]-9], rt
);
583 if (opt
->is_changed
) {
585 ip_send_check(skb
->nh
.iph
);
589 int ip_options_rcv_srr(struct sk_buff
*skb
)
591 struct ip_options
*opt
= &(IPCB(skb
)->opt
);
592 int srrspace
, srrptr
;
594 struct iphdr
*iph
= skb
->nh
.iph
;
595 unsigned char * optptr
= skb
->nh
.raw
+ opt
->srr
;
596 struct rtable
*rt
= (struct rtable
*)skb
->dst
;
603 if (skb
->pkt_type
!= PACKET_HOST
)
605 if (rt
->rt_type
== RTN_UNICAST
) {
606 if (!opt
->is_strictroute
)
608 icmp_send(skb
, ICMP_PARAMETERPROB
, 0, htonl(16<<24));
611 if (rt
->rt_type
!= RTN_LOCAL
)
614 for (srrptr
=optptr
[2], srrspace
= optptr
[1]; srrptr
<= srrspace
; srrptr
+= 4) {
615 if (srrptr
+ 3 > srrspace
) {
616 icmp_send(skb
, ICMP_PARAMETERPROB
, 0, htonl((opt
->srr
+2)<<24));
619 memcpy(&nexthop
, &optptr
[srrptr
-1], 4);
621 rt
= (struct rtable
*)skb
->dst
;
623 err
= ip_route_input(skb
, nexthop
, iph
->saddr
, iph
->tos
, skb
->dev
);
624 rt2
= (struct rtable
*)skb
->dst
;
625 if (err
|| (rt2
->rt_type
!= RTN_UNICAST
&& rt2
->rt_type
!= RTN_LOCAL
)) {
627 skb
->dst
= &rt
->u
.dst
;
631 if (rt2
->rt_type
!= RTN_LOCAL
)
633 /* Superfast 8) loopback forward */
634 memcpy(&iph
->daddr
, &optptr
[srrptr
-1], 4);
637 if (srrptr
<= srrspace
) {