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);
51 memcpy(iph+opt->srr+iph[opt->srr+1]-4, &daddr, 4);
55 ip_rt_get_source(iph+opt->rr+iph[opt->rr+2]-5, rt);
57 ip_rt_get_source(iph+opt->ts+iph[opt->ts+2]-9, rt);
58 if (opt->ts_needtime) {
62 midtime = htonl((tv.tv_sec % 86400) * 1000 + tv.tv_usec / 1000);
63 memcpy(iph+opt->ts+iph[opt->ts+2]-5, &midtime, 4);
68 memset(iph+opt->rr, IPOPT_NOP, iph[opt->rr+1]);
73 memset(iph+opt->ts, IPOPT_NOP, iph[opt->ts+1]);
75 opt->ts_needaddr = opt->ts_needtime = 0;
80 * Provided (sopt, skb) points to received options,
81 * build in dopt compiled option set appropriate for answering.
82 * i.e. invert SRR option, copy anothers,
83 * and grab room in RR/TS options.
85 * NOTE: dopt cannot point to skb.
88 int ip_options_echo(struct ip_options * dopt, struct sk_buff * skb)
90 struct ip_options *sopt;
91 unsigned char *sptr, *dptr;
96 memset(dopt, 0, sizeof(struct ip_options));
100 sopt = &(IPCB(skb)->opt);
102 if (sopt->optlen == 0) {
107 sptr = skb_network_header(skb);
110 daddr = skb->rtable->rt_spec_dst;
113 optlen = sptr[sopt->rr+1];
114 soffset = sptr[sopt->rr+2];
115 dopt->rr = dopt->optlen + sizeof(struct iphdr);
116 memcpy(dptr, sptr+sopt->rr, optlen);
117 if (sopt->rr_needaddr && soffset <= optlen) {
118 if (soffset + 3 > optlen)
120 dptr[2] = soffset + 4;
121 dopt->rr_needaddr = 1;
124 dopt->optlen += optlen;
127 optlen = sptr[sopt->ts+1];
128 soffset = sptr[sopt->ts+2];
129 dopt->ts = dopt->optlen + sizeof(struct iphdr);
130 memcpy(dptr, sptr+sopt->ts, optlen);
131 if (soffset <= optlen) {
132 if (sopt->ts_needaddr) {
133 if (soffset + 3 > optlen)
135 dopt->ts_needaddr = 1;
138 if (sopt->ts_needtime) {
139 if (soffset + 3 > optlen)
141 if ((dptr[3]&0xF) != IPOPT_TS_PRESPEC) {
142 dopt->ts_needtime = 1;
145 dopt->ts_needtime = 0;
147 if (soffset + 8 <= optlen) {
150 memcpy(&addr, sptr+soffset-1, 4);
151 if (inet_addr_type(&init_net, addr) != RTN_LOCAL) {
152 dopt->ts_needtime = 1;
161 dopt->optlen += optlen;
164 unsigned char * start = sptr+sopt->srr;
170 if (soffset > optlen)
171 soffset = optlen + 1;
174 memcpy(&faddr, &start[soffset-1], 4);
175 for (soffset-=4, doffset=4; soffset > 3; soffset-=4, doffset+=4)
176 memcpy(&dptr[doffset-1], &start[soffset-1], 4);
178 * RFC1812 requires to fix illegal source routes.
180 if (memcmp(&ip_hdr(skb)->saddr,
181 &start[soffset + 3], 4) == 0)
185 memcpy(&start[doffset-1], &daddr, 4);
191 dopt->srr = dopt->optlen + sizeof(struct iphdr);
192 dopt->optlen += doffset+3;
193 dopt->is_strictroute = sopt->is_strictroute;
197 optlen = sptr[sopt->cipso+1];
198 dopt->cipso = dopt->optlen+sizeof(struct iphdr);
199 memcpy(dptr, sptr+sopt->cipso, optlen);
201 dopt->optlen += optlen;
203 while (dopt->optlen & 3) {
211 * Options "fragmenting", just fill options not
212 * allowed in fragments with NOOPs.
213 * Simple and stupid 8), but the most efficient way.
216 void ip_options_fragment(struct sk_buff * skb)
218 unsigned char *optptr = skb_network_header(skb) + sizeof(struct iphdr);
219 struct ip_options * opt = &(IPCB(skb)->opt);
233 if (optlen<2 || optlen>l)
235 if (!IPOPT_COPIED(*optptr))
236 memset(optptr, IPOPT_NOOP, optlen);
242 opt->rr_needaddr = 0;
243 opt->ts_needaddr = 0;
244 opt->ts_needtime = 0;
249 * Verify options and fill pointers in struct options.
250 * Caller should clear *opt, and set opt->data.
251 * If opt == NULL, then skb->data should point to IP header.
254 int ip_options_compile(struct ip_options * opt, struct sk_buff * skb)
258 unsigned char * optptr;
260 unsigned char * pp_ptr = NULL;
261 struct rtable *rt = skb ? skb->rtable : NULL;
264 opt = &(IPCB(skb)->opt);
265 iph = skb_network_header(skb);
266 opt->optlen = ((struct iphdr *)iph)->ihl*4 - sizeof(struct iphdr);
267 optptr = iph + sizeof(struct iphdr);
270 optptr = opt->__data;
271 iph = optptr - sizeof(struct iphdr);
274 for (l = opt->optlen; l > 0; ) {
277 for (optptr++, l--; l>0; optptr++, l--) {
278 if (*optptr != IPOPT_END) {
290 if (optlen<2 || optlen>l) {
305 /* NB: cf RFC-1812 5.2.4.1 */
311 if (optptr[2] != 4 || optlen < 7 || ((optlen-3) & 3)) {
315 memcpy(&opt->faddr, &optptr[3], 4);
317 memmove(&optptr[3], &optptr[7], optlen-7);
319 opt->is_strictroute = (optptr[0] == IPOPT_SSRR);
320 opt->srr = optptr - iph;
335 if (optptr[2] <= optlen) {
336 if (optptr[2]+3 > optlen) {
341 memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
345 opt->rr_needaddr = 1;
347 opt->rr = optptr - iph;
349 case IPOPT_TIMESTAMP:
362 if (optptr[2] <= optlen) {
363 __be32 *timeptr = NULL;
364 if (optptr[2]+3 > optptr[1]) {
368 switch (optptr[3]&0xF) {
369 case IPOPT_TS_TSONLY:
370 opt->ts = optptr - iph;
372 timeptr = (__be32*)&optptr[optptr[2]-1];
373 opt->ts_needtime = 1;
376 case IPOPT_TS_TSANDADDR:
377 if (optptr[2]+7 > optptr[1]) {
381 opt->ts = optptr - iph;
383 memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
384 timeptr = (__be32*)&optptr[optptr[2]+3];
386 opt->ts_needaddr = 1;
387 opt->ts_needtime = 1;
390 case IPOPT_TS_PRESPEC:
391 if (optptr[2]+7 > optptr[1]) {
395 opt->ts = optptr - iph;
398 memcpy(&addr, &optptr[optptr[2]-1], 4);
399 if (inet_addr_type(&init_net, addr) == RTN_UNICAST)
402 timeptr = (__be32*)&optptr[optptr[2]+3];
404 opt->ts_needtime = 1;
408 if (!skb && !capable(CAP_NET_RAW)) {
417 do_gettimeofday(&tv);
418 midtime = htonl((tv.tv_sec % 86400) * 1000 + tv.tv_usec / 1000);
419 memcpy(timeptr, &midtime, sizeof(__be32));
423 unsigned overflow = optptr[3]>>4;
424 if (overflow == 15) {
428 opt->ts = optptr - iph;
430 optptr[3] = (optptr[3]&0xF)|((overflow+1)<<4);
440 if (optptr[2] == 0 && optptr[3] == 0)
441 opt->router_alert = optptr - iph;
444 if ((!skb && !capable(CAP_NET_RAW)) || opt->cipso) {
448 opt->cipso = optptr - iph;
449 if (cipso_v4_validate(&optptr)) {
457 if (!skb && !capable(CAP_NET_RAW)) {
473 icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((pp_ptr-iph)<<24));
480 * Undo all the changes done by ip_options_compile().
483 void ip_options_undo(struct ip_options * opt)
486 unsigned char * optptr = opt->__data+opt->srr-sizeof(struct iphdr);
487 memmove(optptr+7, optptr+3, optptr[1]-7);
488 memcpy(optptr+3, &opt->faddr, 4);
490 if (opt->rr_needaddr) {
491 unsigned char * optptr = opt->__data+opt->rr-sizeof(struct iphdr);
493 memset(&optptr[optptr[2]-1], 0, 4);
496 unsigned char * optptr = opt->__data+opt->ts-sizeof(struct iphdr);
497 if (opt->ts_needtime) {
499 memset(&optptr[optptr[2]-1], 0, 4);
500 if ((optptr[3]&0xF) == IPOPT_TS_PRESPEC)
503 if (opt->ts_needaddr) {
505 memset(&optptr[optptr[2]-1], 0, 4);
510 static struct ip_options *ip_options_get_alloc(const int optlen)
512 return kzalloc(sizeof(struct ip_options) + ((optlen + 3) & ~3),
516 static int ip_options_get_finish(struct ip_options **optp,
517 struct ip_options *opt, int optlen)
520 opt->__data[optlen++] = IPOPT_END;
521 opt->optlen = optlen;
523 if (optlen && ip_options_compile(opt, NULL)) {
532 int ip_options_get_from_user(struct ip_options **optp, unsigned char __user *data, int optlen)
534 struct ip_options *opt = ip_options_get_alloc(optlen);
538 if (optlen && copy_from_user(opt->__data, data, optlen)) {
542 return ip_options_get_finish(optp, opt, optlen);
545 int ip_options_get(struct ip_options **optp, unsigned char *data, int optlen)
547 struct ip_options *opt = ip_options_get_alloc(optlen);
552 memcpy(opt->__data, data, optlen);
553 return ip_options_get_finish(optp, opt, optlen);
556 void ip_forward_options(struct sk_buff *skb)
558 struct ip_options * opt = &(IPCB(skb)->opt);
559 unsigned char * optptr;
560 struct rtable *rt = skb->rtable;
561 unsigned char *raw = skb_network_header(skb);
563 if (opt->rr_needaddr) {
564 optptr = (unsigned char *)raw + opt->rr;
565 ip_rt_get_source(&optptr[optptr[2]-5], rt);
568 if (opt->srr_is_hit) {
569 int srrptr, srrspace;
571 optptr = raw + opt->srr;
573 for ( srrptr=optptr[2], srrspace = optptr[1];
577 if (srrptr + 3 > srrspace)
579 if (memcmp(&rt->rt_dst, &optptr[srrptr-1], 4) == 0)
582 if (srrptr + 3 <= srrspace) {
584 ip_rt_get_source(&optptr[srrptr-1], rt);
585 ip_hdr(skb)->daddr = rt->rt_dst;
586 optptr[2] = srrptr+4;
587 } else if (net_ratelimit())
588 printk(KERN_CRIT "ip_forward(): Argh! Destination lost!\n");
589 if (opt->ts_needaddr) {
590 optptr = raw + opt->ts;
591 ip_rt_get_source(&optptr[optptr[2]-9], rt);
595 if (opt->is_changed) {
597 ip_send_check(ip_hdr(skb));
601 int ip_options_rcv_srr(struct sk_buff *skb)
603 struct ip_options *opt = &(IPCB(skb)->opt);
604 int srrspace, srrptr;
606 struct iphdr *iph = ip_hdr(skb);
607 unsigned char *optptr = skb_network_header(skb) + opt->srr;
608 struct rtable *rt = skb->rtable;
615 if (skb->pkt_type != PACKET_HOST)
617 if (rt->rt_type == RTN_UNICAST) {
618 if (!opt->is_strictroute)
620 icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl(16<<24));
623 if (rt->rt_type != RTN_LOCAL)
626 for (srrptr=optptr[2], srrspace = optptr[1]; srrptr <= srrspace; srrptr += 4) {
627 if (srrptr + 3 > srrspace) {
628 icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((opt->srr+2)<<24));
631 memcpy(&nexthop, &optptr[srrptr-1], 4);
635 err = ip_route_input(skb, nexthop, iph->saddr, iph->tos, skb->dev);
637 if (err || (rt2->rt_type != RTN_UNICAST && rt2->rt_type != RTN_LOCAL)) {
643 if (rt2->rt_type != RTN_LOCAL)
645 /* Superfast 8) loopback forward */
646 memcpy(&iph->daddr, &optptr[srrptr-1], 4);
649 if (srrptr <= srrspace) {