[deliverable/linux.git] / net / ipv4 / ip_options.c

/*
 * INET		An implementation of the TCP/IP protocol suite for the LINUX
 *		operating system.  INET is implemented using the  BSD Socket
 *		interface as the means of communication with the user level.
 *
 *		The options processing module for ip.c
 *
 * Authors:	A.N.Kuznetsov
 *
 */

#define pr_fmt(fmt) "IPv4: " fmt

#include <linux/capability.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <asm/uaccess.h>
#include <asm/unaligned.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/icmp.h>
#include <linux/netdevice.h>
#include <linux/rtnetlink.h>
#include <net/sock.h>
#include <net/ip.h>
#include <net/icmp.h>
#include <net/route.h>
#include <net/cipso_ipv4.h>
#include <net/ip_fib.h>

/*
 * Write options to IP header, record destination address to
 * source route option, address of outgoing interface
 * (we should already know it, so that this  function is allowed be
 * called only after routing decision) and timestamp,
 * if we originate this datagram.
 *
 * daddr is real destination address, next hop is recorded in IP header.
 * saddr is address of outgoing interface.
 */

void ip_options_build(struct sk_buff *skb, struct ip_options *opt,
		      __be32 daddr, struct rtable *rt, int is_frag)
{
	unsigned char *iph = skb_network_header(skb);

	memcpy(&(IPCB(skb)->opt), opt, sizeof(struct ip_options));
	memcpy(iph+sizeof(struct iphdr), opt->__data, opt->optlen);
	opt = &(IPCB(skb)->opt);

	if (opt->srr)
		memcpy(iph+opt->srr+iph[opt->srr+1]-4, &daddr, 4);

	if (!is_frag) {
		if (opt->rr_needaddr)
			ip_rt_get_source(iph+opt->rr+iph[opt->rr+2]-5, skb, rt);
		if (opt->ts_needaddr)
			ip_rt_get_source(iph+opt->ts+iph[opt->ts+2]-9, skb, rt);
		if (opt->ts_needtime) {
			struct timespec tv;
			__be32 midtime;
			getnstimeofday(&tv);
			midtime = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC);
			memcpy(iph+opt->ts+iph[opt->ts+2]-5, &midtime, 4);
		}
		return;
	}
	if (opt->rr) {
		memset(iph+opt->rr, IPOPT_NOP, iph[opt->rr+1]);
		opt->rr = 0;
		opt->rr_needaddr = 0;
	}
	if (opt->ts) {
		memset(iph+opt->ts, IPOPT_NOP, iph[opt->ts+1]);
		opt->ts = 0;
		opt->ts_needaddr = opt->ts_needtime = 0;
	}
}

/*
 * Provided (sopt, skb) points to received options,
 * build in dopt compiled option set appropriate for answering.
 * i.e. invert SRR option, copy anothers,
 * and grab room in RR/TS options.
 *
 * NOTE: dopt cannot point to skb.
 */

int ip_options_echo(struct ip_options *dopt, struct sk_buff *skb)
{
	const struct ip_options *sopt;
	unsigned char *sptr, *dptr;
	int soffset, doffset;
	int	optlen;
	__be32	daddr;

	memset(dopt, 0, sizeof(struct ip_options));

	sopt = &(IPCB(skb)->opt);

	if (sopt->optlen == 0)
		return 0;

	sptr = skb_network_header(skb);
	dptr = dopt->__data;

	daddr = fib_compute_spec_dst(skb);

	if (sopt->rr) {
		optlen  = sptr[sopt->rr+1];
		soffset = sptr[sopt->rr+2];
		dopt->rr = dopt->optlen + sizeof(struct iphdr);
		memcpy(dptr, sptr+sopt->rr, optlen);
		if (sopt->rr_needaddr && soffset <= optlen) {
			if (soffset + 3 > optlen)
				return -EINVAL;
			dptr[2] = soffset + 4;
			dopt->rr_needaddr = 1;
		}
		dptr += optlen;
		dopt->optlen += optlen;
	}
	if (sopt->ts) {
		optlen = sptr[sopt->ts+1];
		soffset = sptr[sopt->ts+2];
		dopt->ts = dopt->optlen + sizeof(struct iphdr);
		memcpy(dptr, sptr+sopt->ts, optlen);
		if (soffset <= optlen) {
			if (sopt->ts_needaddr) {
				if (soffset + 3 > optlen)
					return -EINVAL;
				dopt->ts_needaddr = 1;
				soffset += 4;
			}
			if (sopt->ts_needtime) {
				if (soffset + 3 > optlen)
					return -EINVAL;
				if ((dptr[3]&0xF) != IPOPT_TS_PRESPEC) {
					dopt->ts_needtime = 1;
					soffset += 4;
				} else {
					dopt->ts_needtime = 0;

					if (soffset + 7 <= optlen) {
						__be32 addr;

						memcpy(&addr, dptr+soffset-1, 4);
						if (inet_addr_type(dev_net(skb_dst(skb)->dev), addr) != RTN_UNICAST) {
							dopt->ts_needtime = 1;
							soffset += 8;
						}
					}
				}
			}
			dptr[2] = soffset;
		}
		dptr += optlen;
		dopt->optlen += optlen;
	}
	if (sopt->srr) {
		unsigned char *start = sptr+sopt->srr;
		__be32 faddr;

		optlen  = start[1];
		soffset = start[2];
		doffset = 0;
		if (soffset > optlen)
			soffset = optlen + 1;
		soffset -= 4;
		if (soffset > 3) {
			memcpy(&faddr, &start[soffset-1], 4);
			for (soffset-=4, doffset=4; soffset > 3; soffset-=4, doffset+=4)
				memcpy(&dptr[doffset-1], &start[soffset-1], 4);
			/*
			 * RFC1812 requires to fix illegal source routes.
			 */
			if (memcmp(&ip_hdr(skb)->saddr,
				   &start[soffset + 3], 4) == 0)
				doffset -= 4;
		}
		if (doffset > 3) {
			memcpy(&start[doffset-1], &daddr, 4);
			dopt->faddr = faddr;
			dptr[0] = start[0];
			dptr[1] = doffset+3;
			dptr[2] = 4;
			dptr += doffset+3;
			dopt->srr = dopt->optlen + sizeof(struct iphdr);
			dopt->optlen += doffset+3;
			dopt->is_strictroute = sopt->is_strictroute;
		}
	}
	if (sopt->cipso) {
		optlen  = sptr[sopt->cipso+1];
		dopt->cipso = dopt->optlen+sizeof(struct iphdr);
		memcpy(dptr, sptr+sopt->cipso, optlen);
		dptr += optlen;
		dopt->optlen += optlen;
	}
	while (dopt->optlen & 3) {
		*dptr++ = IPOPT_END;
		dopt->optlen++;
	}
	return 0;
}

/*
 *	Options "fragmenting", just fill options not
 *	allowed in fragments with NOOPs.
 *	Simple and stupid 8), but the most efficient way.
 */

void ip_options_fragment(struct sk_buff *skb)
{
	unsigned char *optptr = skb_network_header(skb) + sizeof(struct iphdr);
	struct ip_options *opt = &(IPCB(skb)->opt);
	int  l = opt->optlen;
	int  optlen;

	while (l > 0) {
		switch (*optptr) {
		case IPOPT_END:
			return;
		case IPOPT_NOOP:
			l--;
			optptr++;
			continue;
		}
		optlen = optptr[1];
		if (optlen<2 || optlen>l)
		  return;
		if (!IPOPT_COPIED(*optptr))
			memset(optptr, IPOPT_NOOP, optlen);
		l -= optlen;
		optptr += optlen;
	}
	opt->ts = 0;
	opt->rr = 0;
	opt->rr_needaddr = 0;
	opt->ts_needaddr = 0;
	opt->ts_needtime = 0;
}

/* helper used by ip_options_compile() to call fib_compute_spec_dst()
 * at most one time.
 */
static void spec_dst_fill(__be32 *spec_dst, struct sk_buff *skb)
{
	if (*spec_dst == htonl(INADDR_ANY))
		*spec_dst = fib_compute_spec_dst(skb);
}

/*
 * Verify options and fill pointers in struct options.
 * Caller should clear *opt, and set opt->data.
 * If opt == NULL, then skb->data should point to IP header.
 */

int ip_options_compile(struct net *net,
		       struct ip_options *opt, struct sk_buff *skb)
{
	__be32 spec_dst = htonl(INADDR_ANY);
	unsigned char *pp_ptr = NULL;
	struct rtable *rt = NULL;
	unsigned char *optptr;
	unsigned char *iph;
	int optlen, l;

	if (skb != NULL) {
		rt = skb_rtable(skb);
		optptr = (unsigned char *)&(ip_hdr(skb)[1]);
	} else
		optptr = opt->__data;
	iph = optptr - sizeof(struct iphdr);

	for (l = opt->optlen; l > 0; ) {
		switch (*optptr) {
		      case IPOPT_END:
			for (optptr++, l--; l>0; optptr++, l--) {
				if (*optptr != IPOPT_END) {
					*optptr = IPOPT_END;
					opt->is_changed = 1;
				}
			}
			goto eol;
		      case IPOPT_NOOP:
			l--;
			optptr++;
			continue;
		}
		optlen = optptr[1];
		if (optlen<2 || optlen>l) {
			pp_ptr = optptr;
			goto error;
		}
		switch (*optptr) {
		      case IPOPT_SSRR:
		      case IPOPT_LSRR:
			if (optlen < 3) {
				pp_ptr = optptr + 1;
				goto error;
			}
			if (optptr[2] < 4) {
				pp_ptr = optptr + 2;
				goto error;
			}
			/* NB: cf RFC-1812 5.2.4.1 */
			if (opt->srr) {
				pp_ptr = optptr;
				goto error;
			}
			if (!skb) {
				if (optptr[2] != 4 || optlen < 7 || ((optlen-3) & 3)) {
					pp_ptr = optptr + 1;
					goto error;
				}
				memcpy(&opt->faddr, &optptr[3], 4);
				if (optlen > 7)
					memmove(&optptr[3], &optptr[7], optlen-7);
			}
			opt->is_strictroute = (optptr[0] == IPOPT_SSRR);
			opt->srr = optptr - iph;
			break;
		      case IPOPT_RR:
			if (opt->rr) {
				pp_ptr = optptr;
				goto error;
			}
			if (optlen < 3) {
				pp_ptr = optptr + 1;
				goto error;
			}
			if (optptr[2] < 4) {
				pp_ptr = optptr + 2;
				goto error;
			}
			if (optptr[2] <= optlen) {
				if (optptr[2]+3 > optlen) {
					pp_ptr = optptr + 2;
					goto error;
				}
				if (rt) {
					spec_dst_fill(&spec_dst, skb);
					memcpy(&optptr[optptr[2]-1], &spec_dst, 4);
					opt->is_changed = 1;
				}
				optptr[2] += 4;
				opt->rr_needaddr = 1;
			}
			opt->rr = optptr - iph;
			break;
		      case IPOPT_TIMESTAMP:
			if (opt->ts) {
				pp_ptr = optptr;
				goto error;
			}
			if (optlen < 4) {
				pp_ptr = optptr + 1;
				goto error;
			}
			if (optptr[2] < 5) {
				pp_ptr = optptr + 2;
				goto error;
			}
			if (optptr[2] <= optlen) {
				unsigned char *timeptr = NULL;
				if (optptr[2]+3 > optptr[1]) {
					pp_ptr = optptr + 2;
					goto error;
				}
				switch (optptr[3]&0xF) {
				      case IPOPT_TS_TSONLY:
					opt->ts = optptr - iph;
					if (skb)
						timeptr = &optptr[optptr[2]-1];
					opt->ts_needtime = 1;
					optptr[2] += 4;
					break;
				      case IPOPT_TS_TSANDADDR:
					if (optptr[2]+7 > optptr[1]) {
						pp_ptr = optptr + 2;
						goto error;
					}
					opt->ts = optptr - iph;
					if (rt)  {
						spec_dst_fill(&spec_dst, skb);
						memcpy(&optptr[optptr[2]-1], &spec_dst, 4);
						timeptr = &optptr[optptr[2]+3];
					}
					opt->ts_needaddr = 1;
					opt->ts_needtime = 1;
					optptr[2] += 8;
					break;
				      case IPOPT_TS_PRESPEC:
					if (optptr[2]+7 > optptr[1]) {
						pp_ptr = optptr + 2;
						goto error;
					}
					opt->ts = optptr - iph;
					{
						__be32 addr;
						memcpy(&addr, &optptr[optptr[2]-1], 4);
						if (inet_addr_type(net, addr) == RTN_UNICAST)
							break;
						if (skb)
							timeptr = &optptr[optptr[2]+3];
					}
					opt->ts_needtime = 1;
					optptr[2] += 8;
					break;
				      default:
					if (!skb && !capable(CAP_NET_RAW)) {
						pp_ptr = optptr + 3;
						goto error;
					}
					break;
				}
				if (timeptr) {
					struct timespec tv;
					u32  midtime;
					getnstimeofday(&tv);
					midtime = (tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC;
					put_unaligned_be32(midtime, timeptr);
					opt->is_changed = 1;
				}
			} else {
				unsigned int overflow = optptr[3]>>4;
				if (overflow == 15) {
					pp_ptr = optptr + 3;
					goto error;
				}
				opt->ts = optptr - iph;
				if (skb) {
					optptr[3] = (optptr[3]&0xF)|((overflow+1)<<4);
					opt->is_changed = 1;
				}
			}
			break;
		      case IPOPT_RA:
			if (optlen < 4) {
				pp_ptr = optptr + 1;
				goto error;
			}
			if (optptr[2] == 0 && optptr[3] == 0)
				opt->router_alert = optptr - iph;
			break;
		      case IPOPT_CIPSO:
			if ((!skb && !capable(CAP_NET_RAW)) || opt->cipso) {
				pp_ptr = optptr;
				goto error;
			}
			opt->cipso = optptr - iph;
			if (cipso_v4_validate(skb, &optptr)) {
				pp_ptr = optptr;
				goto error;
			}
			break;
		      case IPOPT_SEC:
		      case IPOPT_SID:
		      default:
			if (!skb && !capable(CAP_NET_RAW)) {
				pp_ptr = optptr;
				goto error;
			}
			break;
		}
		l -= optlen;
		optptr += optlen;
	}

eol:
	if (!pp_ptr)
		return 0;

error:
	if (skb) {
		icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((pp_ptr-iph)<<24));
	}
	return -EINVAL;
}
EXPORT_SYMBOL(ip_options_compile);

/*
 *	Undo all the changes done by ip_options_compile().
 */

void ip_options_undo(struct ip_options *opt)
{
	if (opt->srr) {
		unsigned  char *optptr = opt->__data+opt->srr-sizeof(struct  iphdr);
		memmove(optptr+7, optptr+3, optptr[1]-7);
		memcpy(optptr+3, &opt->faddr, 4);
	}
	if (opt->rr_needaddr) {
		unsigned  char *optptr = opt->__data+opt->rr-sizeof(struct  iphdr);
		optptr[2] -= 4;
		memset(&optptr[optptr[2]-1], 0, 4);
	}
	if (opt->ts) {
		unsigned  char *optptr = opt->__data+opt->ts-sizeof(struct  iphdr);
		if (opt->ts_needtime) {
			optptr[2] -= 4;
			memset(&optptr[optptr[2]-1], 0, 4);
			if ((optptr[3]&0xF) == IPOPT_TS_PRESPEC)
				optptr[2] -= 4;
		}
		if (opt->ts_needaddr) {
			optptr[2] -= 4;
			memset(&optptr[optptr[2]-1], 0, 4);
		}
	}
}

static struct ip_options_rcu *ip_options_get_alloc(const int optlen)
{
	return kzalloc(sizeof(struct ip_options_rcu) + ((optlen + 3) & ~3),
		       GFP_KERNEL);
}

static int ip_options_get_finish(struct net *net, struct ip_options_rcu **optp,
				 struct ip_options_rcu *opt, int optlen)
{
	while (optlen & 3)
		opt->opt.__data[optlen++] = IPOPT_END;
	opt->opt.optlen = optlen;
	if (optlen && ip_options_compile(net, &opt->opt, NULL)) {
		kfree(opt);
		return -EINVAL;
	}
	kfree(*optp);
	*optp = opt;
	return 0;
}

int ip_options_get_from_user(struct net *net, struct ip_options_rcu **optp,
			     unsigned char __user *data, int optlen)
{
	struct ip_options_rcu *opt = ip_options_get_alloc(optlen);

	if (!opt)
		return -ENOMEM;
	if (optlen && copy_from_user(opt->opt.__data, data, optlen)) {
		kfree(opt);
		return -EFAULT;
	}
	return ip_options_get_finish(net, optp, opt, optlen);
}

int ip_options_get(struct net *net, struct ip_options_rcu **optp,
		   unsigned char *data, int optlen)
{
	struct ip_options_rcu *opt = ip_options_get_alloc(optlen);

	if (!opt)
		return -ENOMEM;
	if (optlen)
		memcpy(opt->opt.__data, data, optlen);
	return ip_options_get_finish(net, optp, opt, optlen);
}

void ip_forward_options(struct sk_buff *skb)
{
	struct   ip_options *opt	= &(IPCB(skb)->opt);
	unsigned char *optptr;
	struct rtable *rt = skb_rtable(skb);
	unsigned char *raw = skb_network_header(skb);

	if (opt->rr_needaddr) {
		optptr = (unsigned char *)raw + opt->rr;
		ip_rt_get_source(&optptr[optptr[2]-5], skb, rt);
		opt->is_changed = 1;
	}
	if (opt->srr_is_hit) {
		int srrptr, srrspace;

		optptr = raw + opt->srr;

		for ( srrptr=optptr[2], srrspace = optptr[1];
		     srrptr <= srrspace;
		     srrptr += 4
		     ) {
			if (srrptr + 3 > srrspace)
				break;
			if (memcmp(&opt->nexthop, &optptr[srrptr-1], 4) == 0)
				break;
		}
		if (srrptr + 3 <= srrspace) {
			opt->is_changed = 1;
			ip_hdr(skb)->daddr = opt->nexthop;
			ip_rt_get_source(&optptr[srrptr-1], skb, rt);
			optptr[2] = srrptr+4;
		} else {
			net_crit_ratelimited("%s(): Argh! Destination lost!\n",
					     __func__);
		}
		if (opt->ts_needaddr) {
			optptr = raw + opt->ts;
			ip_rt_get_source(&optptr[optptr[2]-9], skb, rt);
			opt->is_changed = 1;
		}
	}
	if (opt->is_changed) {
		opt->is_changed = 0;
		ip_send_check(ip_hdr(skb));
	}
}

int ip_options_rcv_srr(struct sk_buff *skb)
{
	struct ip_options *opt = &(IPCB(skb)->opt);
	int srrspace, srrptr;
	__be32 nexthop;
	struct iphdr *iph = ip_hdr(skb);
	unsigned char *optptr = skb_network_header(skb) + opt->srr;
	struct rtable *rt = skb_rtable(skb);
	struct rtable *rt2;
	unsigned long orefdst;
	int err;

	if (!rt)
		return 0;

	if (skb->pkt_type != PACKET_HOST)
		return -EINVAL;
	if (rt->rt_type == RTN_UNICAST) {
		if (!opt->is_strictroute)
			return 0;
		icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl(16<<24));
		return -EINVAL;
	}
	if (rt->rt_type != RTN_LOCAL)
		return -EINVAL;

	for (srrptr=optptr[2], srrspace = optptr[1]; srrptr <= srrspace; srrptr += 4) {
		if (srrptr + 3 > srrspace) {
			icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((opt->srr+2)<<24));
			return -EINVAL;
		}
		memcpy(&nexthop, &optptr[srrptr-1], 4);

		orefdst = skb->_skb_refdst;
		skb_dst_set(skb, NULL);
		err = ip_route_input(skb, nexthop, iph->saddr, iph->tos, skb->dev);
		rt2 = skb_rtable(skb);
		if (err || (rt2->rt_type != RTN_UNICAST && rt2->rt_type != RTN_LOCAL)) {
			skb_dst_drop(skb);
			skb->_skb_refdst = orefdst;
			return -EINVAL;
		}
		refdst_drop(orefdst);
		if (rt2->rt_type != RTN_LOCAL)
			break;
		/* Superfast 8) loopback forward */
		iph->daddr = nexthop;
		opt->is_changed = 1;
	}
	if (srrptr <= srrspace) {
		opt->srr_is_hit = 1;
		opt->nexthop = nexthop;
		opt->is_changed = 1;
	}
	return 0;
}
EXPORT_SYMBOL(ip_options_rcv_srr);
Commit	Line	Data
1da177e4 LT	1	/*
	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.
	5	*
	6	* The options processing module for ip.c
	7	*
1da177e4	8	* Authors: A.N.Kuznetsov
e905a9ed	9	*
1da177e4 LT	10	*/
1da177e4 LT	11
afd46503 JP	12	#define pr_fmt(fmt) "IPv4: " fmt
afd46503 JP	13
4fc268d2	14	#include <linux/capability.h>
1da177e4	15	#include <linux/module.h>
5a0e3ad6	16	#include <linux/slab.h>
1da177e4 LT	17	#include <linux/types.h>
1da177e4 LT	18	#include <asm/uaccess.h>
48bdf072	19	#include <asm/unaligned.h>
1da177e4 LT	20	#include <linux/skbuff.h>
	21	#include <linux/ip.h>
	22	#include <linux/icmp.h>
	23	#include <linux/netdevice.h>
	24	#include <linux/rtnetlink.h>
	25	#include <net/sock.h>
	26	#include <net/ip.h>
	27	#include <net/icmp.h>
14c85021	28	#include <net/route.h>
11a03f78	29	#include <net/cipso_ipv4.h>
35ebf65e	30	#include <net/ip_fib.h>
1da177e4	31
e905a9ed	32	/*
1da177e4 LT	33	* Write options to IP header, record destination address to
	34	* source route option, address of outgoing interface
	35	* (we should already know it, so that this function is allowed be
	36	* called only after routing decision) and timestamp,
	37	* if we originate this datagram.
	38	*
	39	* daddr is real destination address, next hop is recorded in IP header.
	40	* saddr is address of outgoing interface.
	41	*/
	42
f6d8bd05	43	void ip_options_build(struct sk_buff skb, struct ip_options opt,
8e36360a	44	__be32 daddr, struct rtable *rt, int is_frag)
1da177e4	45	{
d56f90a7	46	unsigned char *iph = skb_network_header(skb);
1da177e4 LT	47
	48	memcpy(&(IPCB(skb)->opt), opt, sizeof(struct ip_options));
	49	memcpy(iph+sizeof(struct iphdr), opt->__data, opt->optlen);
	50	opt = &(IPCB(skb)->opt);
1da177e4 LT	51
	52	if (opt->srr)
	53	memcpy(iph+opt->srr+iph[opt->srr+1]-4, &daddr, 4);
	54
	55	if (!is_frag) {
	56	if (opt->rr_needaddr)
8e36360a	57	ip_rt_get_source(iph+opt->rr+iph[opt->rr+2]-5, skb, rt);
1da177e4	58	if (opt->ts_needaddr)
8e36360a	59	ip_rt_get_source(iph+opt->ts+iph[opt->ts+2]-9, skb, rt);
1da177e4	60	if (opt->ts_needtime) {
f25c3d61	61	struct timespec tv;
e25d2ca6	62	__be32 midtime;
f25c3d61 YH	63	getnstimeofday(&tv);
f25c3d61 YH	64	midtime = htonl((tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC);
1da177e4 LT	65	memcpy(iph+opt->ts+iph[opt->ts+2]-5, &midtime, 4);
	66	}
	67	return;
	68	}
	69	if (opt->rr) {
	70	memset(iph+opt->rr, IPOPT_NOP, iph[opt->rr+1]);
	71	opt->rr = 0;
	72	opt->rr_needaddr = 0;
	73	}
	74	if (opt->ts) {
	75	memset(iph+opt->ts, IPOPT_NOP, iph[opt->ts+1]);
	76	opt->ts = 0;
	77	opt->ts_needaddr = opt->ts_needtime = 0;
	78	}
	79	}
	80
e905a9ed	81	/*
1da177e4 LT	82	* Provided (sopt, skb) points to received options,
	83	* build in dopt compiled option set appropriate for answering.
	84	* i.e. invert SRR option, copy anothers,
	85	* and grab room in RR/TS options.
	86	*
	87	* NOTE: dopt cannot point to skb.
	88	*/
	89
f6d8bd05	90	int ip_options_echo(struct ip_options dopt, struct sk_buff skb)
1da177e4	91	{
f6d8bd05	92	const struct ip_options *sopt;
1da177e4 LT	93	unsigned char sptr, dptr;
	94	int soffset, doffset;
	95	int optlen;
e25d2ca6	96	__be32 daddr;
1da177e4 LT	97
	98	memset(dopt, 0, sizeof(struct ip_options));
	99
1da177e4 LT	100	sopt = &(IPCB(skb)->opt);
1da177e4 LT	101
f6d8bd05	102	if (sopt->optlen == 0)
1da177e4	103	return 0;
1da177e4	104
d56f90a7	105	sptr = skb_network_header(skb);
1da177e4 LT	106	dptr = dopt->__data;
1da177e4 LT	107
35ebf65e	108	daddr = fib_compute_spec_dst(skb);
1da177e4 LT	109
	110	if (sopt->rr) {
	111	optlen = sptr[sopt->rr+1];
	112	soffset = sptr[sopt->rr+2];
	113	dopt->rr = dopt->optlen + sizeof(struct iphdr);
	114	memcpy(dptr, sptr+sopt->rr, optlen);
	115	if (sopt->rr_needaddr && soffset <= optlen) {
	116	if (soffset + 3 > optlen)
	117	return -EINVAL;
	118	dptr[2] = soffset + 4;
	119	dopt->rr_needaddr = 1;
	120	}
	121	dptr += optlen;
	122	dopt->optlen += optlen;
	123	}
	124	if (sopt->ts) {
	125	optlen = sptr[sopt->ts+1];
	126	soffset = sptr[sopt->ts+2];
	127	dopt->ts = dopt->optlen + sizeof(struct iphdr);
	128	memcpy(dptr, sptr+sopt->ts, optlen);
	129	if (soffset <= optlen) {
	130	if (sopt->ts_needaddr) {
	131	if (soffset + 3 > optlen)
	132	return -EINVAL;
	133	dopt->ts_needaddr = 1;
	134	soffset += 4;
	135	}
	136	if (sopt->ts_needtime) {
	137	if (soffset + 3 > optlen)
	138	return -EINVAL;
	139	if ((dptr[3]&0xF) != IPOPT_TS_PRESPEC) {
	140	dopt->ts_needtime = 1;
	141	soffset += 4;
	142	} else {
	143	dopt->ts_needtime = 0;
	144
8628bd8a	145	if (soffset + 7 <= optlen) {
fd683222	146	__be32 addr;
1da177e4	147
8628bd8a JL	148	memcpy(&addr, dptr+soffset-1, 4);
8628bd8a JL	149	if (inet_addr_type(dev_net(skb_dst(skb)->dev), addr) != RTN_UNICAST) {
1da177e4 LT	150	dopt->ts_needtime = 1;
	151	soffset += 8;
	152	}
	153	}
	154	}
	155	}
	156	dptr[2] = soffset;
	157	}
	158	dptr += optlen;
	159	dopt->optlen += optlen;
	160	}
	161	if (sopt->srr) {
f6d8bd05	162	unsigned char *start = sptr+sopt->srr;
3ca3c68e	163	__be32 faddr;
1da177e4 LT	164
	165	optlen = start[1];
	166	soffset = start[2];
	167	doffset = 0;
	168	if (soffset > optlen)
	169	soffset = optlen + 1;
	170	soffset -= 4;
	171	if (soffset > 3) {
	172	memcpy(&faddr, &start[soffset-1], 4);
	173	for (soffset-=4, doffset=4; soffset > 3; soffset-=4, doffset+=4)
	174	memcpy(&dptr[doffset-1], &start[soffset-1], 4);
	175	/*
	176	* RFC1812 requires to fix illegal source routes.
	177	*/
eddc9ec5 ACM	178	if (memcmp(&ip_hdr(skb)->saddr,
eddc9ec5 ACM	179	&start[soffset + 3], 4) == 0)
1da177e4 LT	180	doffset -= 4;
	181	}
	182	if (doffset > 3) {
	183	memcpy(&start[doffset-1], &daddr, 4);
	184	dopt->faddr = faddr;
	185	dptr[0] = start[0];
	186	dptr[1] = doffset+3;
	187	dptr[2] = 4;
	188	dptr += doffset+3;
	189	dopt->srr = dopt->optlen + sizeof(struct iphdr);
	190	dopt->optlen += doffset+3;
	191	dopt->is_strictroute = sopt->is_strictroute;
	192	}
	193	}
11a03f78 PM	194	if (sopt->cipso) {
	195	optlen = sptr[sopt->cipso+1];
	196	dopt->cipso = dopt->optlen+sizeof(struct iphdr);
	197	memcpy(dptr, sptr+sopt->cipso, optlen);
	198	dptr += optlen;
	199	dopt->optlen += optlen;
	200	}
1da177e4 LT	201	while (dopt->optlen & 3) {
	202	*dptr++ = IPOPT_END;
	203	dopt->optlen++;
	204	}
	205	return 0;
	206	}
	207
	208	/*
	209	* Options "fragmenting", just fill options not
	210	* allowed in fragments with NOOPs.
	211	* Simple and stupid 8), but the most efficient way.
	212	*/
	213
5e73ea1a	214	void ip_options_fragment(struct sk_buff *skb)
1da177e4	215	{
d56f90a7	216	unsigned char *optptr = skb_network_header(skb) + sizeof(struct iphdr);
5e73ea1a	217	struct ip_options *opt = &(IPCB(skb)->opt);
1da177e4 LT	218	int l = opt->optlen;
	219	int optlen;
	220
	221	while (l > 0) {
	222	switch (*optptr) {
	223	case IPOPT_END:
	224	return;
	225	case IPOPT_NOOP:
	226	l--;
	227	optptr++;
	228	continue;
	229	}
	230	optlen = optptr[1];
	231	if (optlen<2 \|\| optlen>l)
	232	return;
	233	if (!IPOPT_COPIED(*optptr))
	234	memset(optptr, IPOPT_NOOP, optlen);
	235	l -= optlen;
	236	optptr += optlen;
	237	}
	238	opt->ts = 0;
	239	opt->rr = 0;
	240	opt->rr_needaddr = 0;
	241	opt->ts_needaddr = 0;
	242	opt->ts_needtime = 0;
1da177e4 LT	243	}
1da177e4 LT	244
bf5e53e3 ED	245	/* helper used by ip_options_compile() to call fib_compute_spec_dst()
	246	* at most one time.
	247	*/
	248	static void spec_dst_fill(__be32 spec_dst, struct sk_buff skb)
	249	{
	250	if (*spec_dst == htonl(INADDR_ANY))
	251	*spec_dst = fib_compute_spec_dst(skb);
	252	}
	253
1da177e4 LT	254	/*
	255	* Verify options and fill pointers in struct options.
	256	* Caller should clear *opt, and set opt->data.
	257	* If opt == NULL, then skb->data should point to IP header.
	258	*/
	259
0e6bd4a1	260	int ip_options_compile(struct net *net,
5e73ea1a	261	struct ip_options opt, struct sk_buff skb)
1da177e4	262	{
bf5e53e3	263	__be32 spec_dst = htonl(INADDR_ANY);
5e73ea1a	264	unsigned char *pp_ptr = NULL;
11604721	265	struct rtable *rt = NULL;
35ebf65e DM	266	unsigned char *optptr;
	267	unsigned char *iph;
	268	int optlen, l;
1da177e4	269
22aba383	270	if (skb != NULL) {
11604721	271	rt = skb_rtable(skb);
22aba383 DL	272	optptr = (unsigned char *)&(ip_hdr(skb)[1]);
22aba383 DL	273	} else
10fe7d85	274	optptr = opt->__data;
22aba383	275	iph = optptr - sizeof(struct iphdr);
1da177e4 LT	276
	277	for (l = opt->optlen; l > 0; ) {
	278	switch (*optptr) {
	279	case IPOPT_END:
	280	for (optptr++, l--; l>0; optptr++, l--) {
	281	if (*optptr != IPOPT_END) {
	282	*optptr = IPOPT_END;
	283	opt->is_changed = 1;
	284	}
	285	}
	286	goto eol;
	287	case IPOPT_NOOP:
	288	l--;
	289	optptr++;
	290	continue;
	291	}
	292	optlen = optptr[1];
	293	if (optlen<2 \|\| optlen>l) {
	294	pp_ptr = optptr;
	295	goto error;
	296	}
	297	switch (*optptr) {
	298	case IPOPT_SSRR:
	299	case IPOPT_LSRR:
	300	if (optlen < 3) {
	301	pp_ptr = optptr + 1;
	302	goto error;
	303	}
	304	if (optptr[2] < 4) {
	305	pp_ptr = optptr + 2;
	306	goto error;
	307	}
	308	/* NB: cf RFC-1812 5.2.4.1 */
	309	if (opt->srr) {
	310	pp_ptr = optptr;
	311	goto error;
	312	}
	313	if (!skb) {
	314	if (optptr[2] != 4 \|\| optlen < 7 \|\| ((optlen-3) & 3)) {
	315	pp_ptr = optptr + 1;
	316	goto error;
	317	}
	318	memcpy(&opt->faddr, &optptr[3], 4);
	319	if (optlen > 7)
	320	memmove(&optptr[3], &optptr[7], optlen-7);
	321	}
	322	opt->is_strictroute = (optptr[0] == IPOPT_SSRR);
	323	opt->srr = optptr - iph;
	324	break;
	325	case IPOPT_RR:
	326	if (opt->rr) {
	327	pp_ptr = optptr;
	328	goto error;
	329	}
	330	if (optlen < 3) {
	331	pp_ptr = optptr + 1;
	332	goto error;
	333	}
	334	if (optptr[2] < 4) {
	335	pp_ptr = optptr + 2;
	336	goto error;
	337	}
	338	if (optptr[2] <= optlen) {
	339	if (optptr[2]+3 > optlen) {
340	pp_ptr = optptr + 2;
341	goto error;
342	}
11604721	343	if (rt) {
bf5e53e3	344	spec_dst_fill(&spec_dst, skb);
35ebf65e	345	memcpy(&optptr[optptr[2]-1], &spec_dst, 4);
1da177e4 LT	346	opt->is_changed = 1;
	347	}
	348	optptr[2] += 4;
	349	opt->rr_needaddr = 1;
	350	}
	351	opt->rr = optptr - iph;
	352	break;
	353	case IPOPT_TIMESTAMP:
	354	if (opt->ts) {
	355	pp_ptr = optptr;
	356	goto error;
	357	}
	358	if (optlen < 4) {
	359	pp_ptr = optptr + 1;
	360	goto error;
	361	}
	362	if (optptr[2] < 5) {
	363	pp_ptr = optptr + 2;
	364	goto error;
	365	}
	366	if (optptr[2] <= optlen) {
48bdf072	367	unsigned char *timeptr = NULL;
1da177e4 LT	368	if (optptr[2]+3 > optptr[1]) {
	369	pp_ptr = optptr + 2;
	370	goto error;
	371	}
	372	switch (optptr[3]&0xF) {
	373	case IPOPT_TS_TSONLY:
	374	opt->ts = optptr - iph;
e905a9ed	375	if (skb)
48bdf072	376	timeptr = &optptr[optptr[2]-1];
1da177e4 LT	377	opt->ts_needtime = 1;
	378	optptr[2] += 4;
	379	break;
	380	case IPOPT_TS_TSANDADDR:
	381	if (optptr[2]+7 > optptr[1]) {
	382	pp_ptr = optptr + 2;
	383	goto error;
	384	}
	385	opt->ts = optptr - iph;
11604721	386	if (rt) {
bf5e53e3	387	spec_dst_fill(&spec_dst, skb);
35ebf65e	388	memcpy(&optptr[optptr[2]-1], &spec_dst, 4);
48bdf072	389	timeptr = &optptr[optptr[2]+3];
1da177e4 LT	390	}
	391	opt->ts_needaddr = 1;
	392	opt->ts_needtime = 1;
	393	optptr[2] += 8;
	394	break;
	395	case IPOPT_TS_PRESPEC:
	396	if (optptr[2]+7 > optptr[1]) {
	397	pp_ptr = optptr + 2;
	398	goto error;
	399	}
	400	opt->ts = optptr - iph;
	401	{
fd683222	402	__be32 addr;
1da177e4	403	memcpy(&addr, &optptr[optptr[2]-1], 4);
0e6bd4a1	404	if (inet_addr_type(net, addr) == RTN_UNICAST)
1da177e4 LT	405	break;
1da177e4 LT	406	if (skb)
48bdf072	407	timeptr = &optptr[optptr[2]+3];
1da177e4 LT	408	}
	409	opt->ts_needtime = 1;
	410	optptr[2] += 8;
	411	break;
	412	default:
	413	if (!skb && !capable(CAP_NET_RAW)) {
	414	pp_ptr = optptr + 3;
	415	goto error;
	416	}
	417	break;
	418	}
	419	if (timeptr) {
f25c3d61	420	struct timespec tv;
48bdf072	421	u32 midtime;
f25c3d61	422	getnstimeofday(&tv);
48bdf072 CM	423	midtime = (tv.tv_sec % 86400) * MSEC_PER_SEC + tv.tv_nsec / NSEC_PER_MSEC;
48bdf072 CM	424	put_unaligned_be32(midtime, timeptr);
1da177e4 LT	425	opt->is_changed = 1;
	426	}
	427	} else {
95c96174	428	unsigned int overflow = optptr[3]>>4;
1da177e4 LT	429	if (overflow == 15) {
	430	pp_ptr = optptr + 3;
	431	goto error;
	432	}
	433	opt->ts = optptr - iph;
	434	if (skb) {
	435	optptr[3] = (optptr[3]&0xF)\|((overflow+1)<<4);
	436	opt->is_changed = 1;
	437	}
	438	}
	439	break;
	440	case IPOPT_RA:
	441	if (optlen < 4) {
	442	pp_ptr = optptr + 1;
	443	goto error;
	444	}
	445	if (optptr[2] == 0 && optptr[3] == 0)
	446	opt->router_alert = optptr - iph;
	447	break;
11a03f78	448	case IPOPT_CIPSO:
f8687afe	449	if ((!skb && !capable(CAP_NET_RAW)) \|\| opt->cipso) {
11a03f78 PM	450	pp_ptr = optptr;
	451	goto error;
	452	}
	453	opt->cipso = optptr - iph;
15c45f7b	454	if (cipso_v4_validate(skb, &optptr)) {
11a03f78 PM	455	pp_ptr = optptr;
	456	goto error;
	457	}
	458	break;
1da177e4 LT	459	case IPOPT_SEC:
	460	case IPOPT_SID:
	461	default:
	462	if (!skb && !capable(CAP_NET_RAW)) {
	463	pp_ptr = optptr;
	464	goto error;
	465	}
	466	break;
	467	}
	468	l -= optlen;
	469	optptr += optlen;
	470	}
	471
	472	eol:
	473	if (!pp_ptr)
	474	return 0;
	475
	476	error:
	477	if (skb) {
	478	icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((pp_ptr-iph)<<24));
	479	}
	480	return -EINVAL;
	481	}
462fb2af	482	EXPORT_SYMBOL(ip_options_compile);
1da177e4 LT	483
	484	/*
	485	* Undo all the changes done by ip_options_compile().
	486	*/
	487
5e73ea1a	488	void ip_options_undo(struct ip_options *opt)
1da177e4 LT	489	{
1da177e4 LT	490	if (opt->srr) {
5e73ea1a	491	unsigned char *optptr = opt->__data+opt->srr-sizeof(struct iphdr);
1da177e4 LT	492	memmove(optptr+7, optptr+3, optptr[1]-7);
	493	memcpy(optptr+3, &opt->faddr, 4);
	494	}
	495	if (opt->rr_needaddr) {
5e73ea1a	496	unsigned char *optptr = opt->__data+opt->rr-sizeof(struct iphdr);
1da177e4 LT	497	optptr[2] -= 4;
	498	memset(&optptr[optptr[2]-1], 0, 4);
	499	}
	500	if (opt->ts) {
5e73ea1a	501	unsigned char *optptr = opt->__data+opt->ts-sizeof(struct iphdr);
1da177e4 LT	502	if (opt->ts_needtime) {
	503	optptr[2] -= 4;
	504	memset(&optptr[optptr[2]-1], 0, 4);
	505	if ((optptr[3]&0xF) == IPOPT_TS_PRESPEC)
	506	optptr[2] -= 4;
	507	}
	508	if (opt->ts_needaddr) {
	509	optptr[2] -= 4;
	510	memset(&optptr[optptr[2]-1], 0, 4);
	511	}
	512	}
	513	}
	514
f6d8bd05	515	static struct ip_options_rcu *ip_options_get_alloc(const int optlen)
1da177e4	516	{
f6d8bd05	517	return kzalloc(sizeof(struct ip_options_rcu) + ((optlen + 3) & ~3),
37640703	518	GFP_KERNEL);
4c6ea29d	519	}
1da177e4	520
f6d8bd05 ED	521	static int ip_options_get_finish(struct net net, struct ip_options_rcu *optp,
f6d8bd05 ED	522	struct ip_options_rcu *opt, int optlen)
4c6ea29d	523	{
1da177e4	524	while (optlen & 3)
f6d8bd05 ED	525	opt->opt.__data[optlen++] = IPOPT_END;
	526	opt->opt.optlen = optlen;
	527	if (optlen && ip_options_compile(net, &opt->opt, NULL)) {
1da177e4 LT	528	kfree(opt);
	529	return -EINVAL;
	530	}
a51482bd	531	kfree(*optp);
1da177e4 LT	532	*optp = opt;
	533	return 0;
	534	}
	535
f6d8bd05	536	int ip_options_get_from_user(struct net net, struct ip_options_rcu *optp,
f2c4802b	537	unsigned char __user *data, int optlen)
4c6ea29d	538	{
f6d8bd05	539	struct ip_options_rcu *opt = ip_options_get_alloc(optlen);
4c6ea29d ACM	540
	541	if (!opt)
	542	return -ENOMEM;
f6d8bd05	543	if (optlen && copy_from_user(opt->opt.__data, data, optlen)) {
4c6ea29d ACM	544	kfree(opt);
	545	return -EFAULT;
	546	}
f2c4802b	547	return ip_options_get_finish(net, optp, opt, optlen);
4c6ea29d ACM	548	}
4c6ea29d ACM	549
f6d8bd05	550	int ip_options_get(struct net net, struct ip_options_rcu *optp,
f2c4802b	551	unsigned char *data, int optlen)
4c6ea29d	552	{
f6d8bd05	553	struct ip_options_rcu *opt = ip_options_get_alloc(optlen);
4c6ea29d ACM	554
	555	if (!opt)
	556	return -ENOMEM;
	557	if (optlen)
f6d8bd05	558	memcpy(opt->opt.__data, data, optlen);
f2c4802b	559	return ip_options_get_finish(net, optp, opt, optlen);
4c6ea29d ACM	560	}
4c6ea29d ACM	561
1da177e4 LT	562	void ip_forward_options(struct sk_buff *skb)
1da177e4 LT	563	{
5e73ea1a DB	564	struct ip_options *opt = &(IPCB(skb)->opt);
5e73ea1a DB	565	unsigned char *optptr;
511c3f92	566	struct rtable *rt = skb_rtable(skb);
d56f90a7	567	unsigned char *raw = skb_network_header(skb);
1da177e4 LT	568
	569	if (opt->rr_needaddr) {
	570	optptr = (unsigned char *)raw + opt->rr;
8e36360a	571	ip_rt_get_source(&optptr[optptr[2]-5], skb, rt);
1da177e4 LT	572	opt->is_changed = 1;
	573	}
	574	if (opt->srr_is_hit) {
	575	int srrptr, srrspace;
	576
	577	optptr = raw + opt->srr;
	578
	579	for ( srrptr=optptr[2], srrspace = optptr[1];
	580	srrptr <= srrspace;
	581	srrptr += 4
	582	) {
	583	if (srrptr + 3 > srrspace)
	584	break;
ac8a4810	585	if (memcmp(&opt->nexthop, &optptr[srrptr-1], 4) == 0)
1da177e4 LT	586	break;
	587	}
	588	if (srrptr + 3 <= srrspace) {
	589	opt->is_changed = 1;
ac8a4810	590	ip_hdr(skb)->daddr = opt->nexthop;
5dc7883f	591	ip_rt_get_source(&optptr[srrptr-1], skb, rt);
1da177e4	592	optptr[2] = srrptr+4;
e87cc472 JP	593	} else {
	594	net_crit_ratelimited("%s(): Argh! Destination lost!\n",
	595	__func__);
	596	}
1da177e4 LT	597	if (opt->ts_needaddr) {
1da177e4 LT	598	optptr = raw + opt->ts;
8e36360a	599	ip_rt_get_source(&optptr[optptr[2]-9], skb, rt);
1da177e4 LT	600	opt->is_changed = 1;
	601	}
	602	}
	603	if (opt->is_changed) {
	604	opt->is_changed = 0;
eddc9ec5	605	ip_send_check(ip_hdr(skb));
1da177e4 LT	606	}
	607	}
	608
	609	int ip_options_rcv_srr(struct sk_buff *skb)
	610	{
	611	struct ip_options *opt = &(IPCB(skb)->opt);
	612	int srrspace, srrptr;
9e12bb22	613	__be32 nexthop;
eddc9ec5	614	struct iphdr *iph = ip_hdr(skb);
d56f90a7	615	unsigned char *optptr = skb_network_header(skb) + opt->srr;
511c3f92	616	struct rtable *rt = skb_rtable(skb);
1da177e4	617	struct rtable *rt2;
7fee226a	618	unsigned long orefdst;
1da177e4 LT	619	int err;
1da177e4 LT	620
10949550	621	if (!rt)
1da177e4 LT	622	return 0;
	623
	624	if (skb->pkt_type != PACKET_HOST)
	625	return -EINVAL;
	626	if (rt->rt_type == RTN_UNICAST) {
	627	if (!opt->is_strictroute)
	628	return 0;
	629	icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl(16<<24));
	630	return -EINVAL;
	631	}
	632	if (rt->rt_type != RTN_LOCAL)
	633	return -EINVAL;
	634
	635	for (srrptr=optptr[2], srrspace = optptr[1]; srrptr <= srrspace; srrptr += 4) {
	636	if (srrptr + 3 > srrspace) {
	637	icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((opt->srr+2)<<24));
	638	return -EINVAL;
	639	}
	640	memcpy(&nexthop, &optptr[srrptr-1], 4);
	641
7fee226a	642	orefdst = skb->_skb_refdst;
adf30907	643	skb_dst_set(skb, NULL);
1da177e4	644	err = ip_route_input(skb, nexthop, iph->saddr, iph->tos, skb->dev);
511c3f92	645	rt2 = skb_rtable(skb);
1da177e4	646	if (err \|\| (rt2->rt_type != RTN_UNICAST && rt2->rt_type != RTN_LOCAL)) {
7fee226a ED	647	skb_dst_drop(skb);
7fee226a ED	648	skb->_skb_refdst = orefdst;
1da177e4 LT	649	return -EINVAL;
1da177e4 LT	650	}
7fee226a	651	refdst_drop(orefdst);
1da177e4 LT	652	if (rt2->rt_type != RTN_LOCAL)
	653	break;
	654	/* Superfast 8) loopback forward */
c30883bd	655	iph->daddr = nexthop;
1da177e4 LT	656	opt->is_changed = 1;
	657	}
	658	if (srrptr <= srrspace) {
	659	opt->srr_is_hit = 1;
ac8a4810	660	opt->nexthop = nexthop;
1da177e4 LT	661	opt->is_changed = 1;
	662	}
	663	return 0;
	664	}
462fb2af	665	EXPORT_SYMBOL(ip_options_rcv_srr);