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 #include <linux/capability.h>
13 #include <linux/module.h>
14 #include <linux/slab.h>
15 #include <linux/types.h>
16 #include <asm/uaccess.h>
17 #include <linux/skbuff.h>
19 #include <linux/icmp.h>
20 #include <linux/netdevice.h>
21 #include <linux/rtnetlink.h>
25 #include <net/route.h>
26 #include <net/cipso_ipv4.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 __be32 daddr, struct rtable *rt, int is_frag)
42 unsigned char *iph = skb_network_header(skb);
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);
49 memcpy(iph+opt->srr+iph[opt->srr+1]-4, &daddr, 4);
53 ip_rt_get_source(iph+opt->rr+iph[opt->rr+2]-5, skb, rt);
55 ip_rt_get_source(iph+opt->ts+iph[opt->ts+2]-9, skb, rt);
56 if (opt->ts_needtime) {
60 midtime = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC);
61 memcpy(iph+opt->ts+iph[opt->ts+2]-5, &midtime, 4);
66 memset(iph+opt->rr, IPOPT_NOP, iph[opt->rr+1]);
71 memset(iph+opt->ts, IPOPT_NOP, iph[opt->ts+1]);
73 opt->ts_needaddr = opt->ts_needtime = 0;
78 * Provided (sopt, skb) points to received options,
79 * build in dopt compiled option set appropriate for answering.
80 * i.e. invert SRR option, copy anothers,
81 * and grab room in RR/TS options.
83 * NOTE: dopt cannot point to skb.
86 int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb)
88 const struct ip_options *sopt;
89 unsigned char *sptr, *dptr;
94 memset(dopt, 0, sizeof(struct ip_options));
96 sopt = &(IPCB(skb)->opt);
98 if (sopt->optlen == 0)
101 sptr = skb_network_header(skb);
104 daddr = skb_rtable(skb)->rt_spec_dst;
107 optlen = sptr[sopt->rr+1];
108 soffset = sptr[sopt->rr+2];
109 dopt->rr = dopt->optlen + sizeof(struct iphdr);
110 memcpy(dptr, sptr+sopt->rr, optlen);
111 if (sopt->rr_needaddr && soffset <= optlen) {
112 if (soffset + 3 > optlen)
114 dptr[2] = soffset + 4;
115 dopt->rr_needaddr = 1;
118 dopt->optlen += optlen;
121 optlen = sptr[sopt->ts+1];
122 soffset = sptr[sopt->ts+2];
123 dopt->ts = dopt->optlen + sizeof(struct iphdr);
124 memcpy(dptr, sptr+sopt->ts, optlen);
125 if (soffset <= optlen) {
126 if (sopt->ts_needaddr) {
127 if (soffset + 3 > optlen)
129 dopt->ts_needaddr = 1;
132 if (sopt->ts_needtime) {
133 if (soffset + 3 > optlen)
135 if ((dptr[3]&0xF) != IPOPT_TS_PRESPEC) {
136 dopt->ts_needtime = 1;
139 dopt->ts_needtime = 0;
141 if (soffset + 7 <= optlen) {
144 memcpy(&addr, dptr+soffset-1, 4);
145 if (inet_addr_type(dev_net(skb_dst(skb)->dev), addr) != RTN_UNICAST) {
146 dopt->ts_needtime = 1;
155 dopt->optlen += optlen;
158 unsigned char *start = sptr+sopt->srr;
164 if (soffset > optlen)
165 soffset = optlen + 1;
168 memcpy(&faddr, &start[soffset-1], 4);
169 for (soffset-=4, doffset=4; soffset > 3; soffset-=4, doffset+=4)
170 memcpy(&dptr[doffset-1], &start[soffset-1], 4);
172 * RFC1812 requires to fix illegal source routes.
174 if (memcmp(&ip_hdr(skb)->saddr,
175 &start[soffset + 3], 4) == 0)
179 memcpy(&start[doffset-1], &daddr, 4);
185 dopt->srr = dopt->optlen + sizeof(struct iphdr);
186 dopt->optlen += doffset+3;
187 dopt->is_strictroute = sopt->is_strictroute;
191 optlen = sptr[sopt->cipso+1];
192 dopt->cipso = dopt->optlen+sizeof(struct iphdr);
193 memcpy(dptr, sptr+sopt->cipso, optlen);
195 dopt->optlen += optlen;
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_network_header(skb) + sizeof(struct iphdr);
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;
242 * Verify options and fill pointers in struct options.
243 * Caller should clear *opt, and set opt->data.
244 * If opt == NULL, then skb->data should point to IP header.
247 int ip_options_compile(struct net *net,
248 struct ip_options * opt, struct sk_buff * skb)
252 unsigned char * optptr;
254 unsigned char * pp_ptr = NULL;
255 struct rtable *rt = NULL;
258 rt = skb_rtable(skb);
259 optptr = (unsigned char *)&(ip_hdr(skb)[1]);
261 optptr = opt->__data;
262 iph = optptr - sizeof(struct iphdr);
264 for (l = opt->optlen; l > 0; ) {
267 for (optptr++, l--; l>0; optptr++, l--) {
268 if (*optptr != IPOPT_END) {
280 if (optlen<2 || optlen>l) {
295 /* NB: cf RFC-1812 5.2.4.1 */
301 if (optptr[2] != 4 || optlen < 7 || ((optlen-3) & 3)) {
305 memcpy(&opt->faddr, &optptr[3], 4);
307 memmove(&optptr[3], &optptr[7], optlen-7);
309 opt->is_strictroute = (optptr[0] == IPOPT_SSRR);
310 opt->srr = optptr - iph;
325 if (optptr[2] <= optlen) {
326 if (optptr[2]+3 > optlen) {
331 memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
335 opt->rr_needaddr = 1;
337 opt->rr = optptr - iph;
339 case IPOPT_TIMESTAMP:
352 if (optptr[2] <= optlen) {
353 __be32 *timeptr = NULL;
354 if (optptr[2]+3 > optptr[1]) {
358 switch (optptr[3]&0xF) {
359 case IPOPT_TS_TSONLY:
360 opt->ts = optptr - iph;
362 timeptr = (__be32*)&optptr[optptr[2]-1];
363 opt->ts_needtime = 1;
366 case IPOPT_TS_TSANDADDR:
367 if (optptr[2]+7 > optptr[1]) {
371 opt->ts = optptr - iph;
373 memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
374 timeptr = (__be32*)&optptr[optptr[2]+3];
376 opt->ts_needaddr = 1;
377 opt->ts_needtime = 1;
380 case IPOPT_TS_PRESPEC:
381 if (optptr[2]+7 > optptr[1]) {
385 opt->ts = optptr - iph;
388 memcpy(&addr, &optptr[optptr[2]-1], 4);
389 if (inet_addr_type(net, addr) == RTN_UNICAST)
392 timeptr = (__be32*)&optptr[optptr[2]+3];
394 opt->ts_needtime = 1;
398 if (!skb && !capable(CAP_NET_RAW)) {
408 midtime = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC);
409 memcpy(timeptr, &midtime, sizeof(__be32));
413 unsigned overflow = optptr[3]>>4;
414 if (overflow == 15) {
418 opt->ts = optptr - iph;
420 optptr[3] = (optptr[3]&0xF)|((overflow+1)<<4);
430 if (optptr[2] == 0 && optptr[3] == 0)
431 opt->router_alert = optptr - iph;
434 if ((!skb && !capable(CAP_NET_RAW)) || opt->cipso) {
438 opt->cipso = optptr - iph;
439 if (cipso_v4_validate(skb, &optptr)) {
447 if (!skb && !capable(CAP_NET_RAW)) {
463 icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((pp_ptr-iph)<<24));
467 EXPORT_SYMBOL(ip_options_compile);
470 * Undo all the changes done by ip_options_compile().
473 void ip_options_undo(struct ip_options * opt)
476 unsigned char * optptr = opt->__data+opt->srr-sizeof(struct iphdr);
477 memmove(optptr+7, optptr+3, optptr[1]-7);
478 memcpy(optptr+3, &opt->faddr, 4);
480 if (opt->rr_needaddr) {
481 unsigned char * optptr = opt->__data+opt->rr-sizeof(struct iphdr);
483 memset(&optptr[optptr[2]-1], 0, 4);
486 unsigned char * optptr = opt->__data+opt->ts-sizeof(struct iphdr);
487 if (opt->ts_needtime) {
489 memset(&optptr[optptr[2]-1], 0, 4);
490 if ((optptr[3]&0xF) == IPOPT_TS_PRESPEC)
493 if (opt->ts_needaddr) {
495 memset(&optptr[optptr[2]-1], 0, 4);
500 static struct ip_options_rcu *ip_options_get_alloc(const int optlen)
502 return kzalloc(sizeof(struct ip_options_rcu) + ((optlen + 3) & ~3),
506 static int ip_options_get_finish(struct net *net, struct ip_options_rcu **optp,
507 struct ip_options_rcu *opt, int optlen)
510 opt->opt.__data[optlen++] = IPOPT_END;
511 opt->opt.optlen = optlen;
512 if (optlen && ip_options_compile(net, &opt->opt, NULL)) {
521 int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
522 unsigned char __user *data, int optlen)
524 struct ip_options_rcu *opt = ip_options_get_alloc(optlen);
528 if (optlen && copy_from_user(opt->opt.__data, data, optlen)) {
532 return ip_options_get_finish(net, optp, opt, optlen);
535 int ip_options_get(struct net *net, struct ip_options_rcu **optp,
536 unsigned char *data, int optlen)
538 struct ip_options_rcu *opt = ip_options_get_alloc(optlen);
543 memcpy(opt->opt.__data, data, optlen);
544 return ip_options_get_finish(net, optp, opt, optlen);
547 void ip_forward_options(struct sk_buff *skb)
549 struct ip_options * opt = &(IPCB(skb)->opt);
550 unsigned char * optptr;
551 struct rtable *rt = skb_rtable(skb);
552 unsigned char *raw = skb_network_header(skb);
554 if (opt->rr_needaddr) {
555 optptr = (unsigned char *)raw + opt->rr;
556 ip_rt_get_source(&optptr[optptr[2]-5], skb, rt);
559 if (opt->srr_is_hit) {
560 int srrptr, srrspace;
562 optptr = raw + opt->srr;
564 for ( srrptr=optptr[2], srrspace = optptr[1];
568 if (srrptr + 3 > srrspace)
570 if (memcmp(&ip_hdr(skb)->daddr, &optptr[srrptr-1], 4) == 0)
573 if (srrptr + 3 <= srrspace) {
575 ip_rt_get_source(&optptr[srrptr-1], skb, rt);
576 optptr[2] = srrptr+4;
577 } else if (net_ratelimit())
578 printk(KERN_CRIT "ip_forward(): Argh! Destination lost!\n");
579 if (opt->ts_needaddr) {
580 optptr = raw + opt->ts;
581 ip_rt_get_source(&optptr[optptr[2]-9], skb, rt);
585 if (opt->is_changed) {
587 ip_send_check(ip_hdr(skb));
591 int ip_options_rcv_srr(struct sk_buff *skb)
593 struct ip_options *opt = &(IPCB(skb)->opt);
594 int srrspace, srrptr;
596 struct iphdr *iph = ip_hdr(skb);
597 unsigned char *optptr = skb_network_header(skb) + opt->srr;
598 struct rtable *rt = skb_rtable(skb);
600 unsigned long orefdst;
606 if (skb->pkt_type != PACKET_HOST)
608 if (rt->rt_type == RTN_UNICAST) {
609 if (!opt->is_strictroute)
611 icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl(16<<24));
614 if (rt->rt_type != RTN_LOCAL)
617 for (srrptr=optptr[2], srrspace = optptr[1]; srrptr <= srrspace; srrptr += 4) {
618 if (srrptr + 3 > srrspace) {
619 icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((opt->srr+2)<<24));
622 memcpy(&nexthop, &optptr[srrptr-1], 4);
624 orefdst = skb->_skb_refdst;
625 skb_dst_set(skb, NULL);
626 err = ip_route_input(skb, nexthop, iph->saddr, iph->tos, skb->dev);
627 rt2 = skb_rtable(skb);
628 if (err || (rt2->rt_type != RTN_UNICAST && rt2->rt_type != RTN_LOCAL)) {
630 skb->_skb_refdst = orefdst;
633 refdst_drop(orefdst);
634 if (rt2->rt_type != RTN_LOCAL)
636 /* Superfast 8) loopback forward */
637 iph->daddr = nexthop;
640 if (srrptr <= srrspace) {
646 EXPORT_SYMBOL(ip_options_rcv_srr);