[linux-2.6-block.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
 *
 * Version:	$Id: ip_options.c,v 1.21 2001/09/01 00:31:50 davem Exp $
 *
 * Authors:	A.N.Kuznetsov
 *
 */

#include <linux/capability.h>
#include <linux/module.h>
#include <linux/types.h>
#include <asm/uaccess.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>

/*
 * 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, rt);
		if (opt->ts_needaddr)
			ip_rt_get_source(iph+opt->ts+iph[opt->ts+2]-9, rt);
		if (opt->ts_needtime) {
			struct timeval tv;
			__be32 midtime;
			do_gettimeofday(&tv);
			midtime = htonl((tv.tv_sec % 86400) * 1000 + tv.tv_usec / 1000);
			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)
{
	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) {
		dopt->optlen = 0;
		return 0;
	}

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

	daddr = skb->rtable->rt_spec_dst;

	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 + 8 <= optlen) {
						__be32 addr;

						memcpy(&addr, sptr+soffset-1, 4);
						if (inet_addr_type(dev_net(skb->dst->dev), addr) != RTN_LOCAL) {
							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;
	return;
}

/*
 * 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)
{
	int l;
	unsigned char * iph;
	unsigned char * optptr;
	int optlen;
	unsigned char * pp_ptr = NULL;
	struct rtable *rt = NULL;

	if (skb != NULL) {
		rt = skb->rtable;
		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 (skb) {
					memcpy(&optptr[optptr[2]-1], &rt->rt_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) {
				__be32 *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 = (__be32*)&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 (skb) {
						memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
						timeptr = (__be32*)&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 = (__be32*)&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 timeval tv;
					__be32  midtime;
					do_gettimeofday(&tv);
					midtime = htonl((tv.tv_sec % 86400) * 1000 + tv.tv_usec / 1000);
					memcpy(timeptr, &midtime, sizeof(__be32));
					opt->is_changed = 1;
				}
			} else {
				unsigned 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(&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;
}


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

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

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

	if (!opt)
		return -ENOMEM;
	if (optlen && copy_from_user(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 **optp,
		   unsigned char *data, int optlen)
{
	struct ip_options *opt = ip_options_get_alloc(optlen);

	if (!opt)
		return -ENOMEM;
	if (optlen)
		memcpy(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;
	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], 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(&rt->rt_dst, &optptr[srrptr-1], 4) == 0)
				break;
		}
		if (srrptr + 3 <= srrspace) {
			opt->is_changed = 1;
			ip_rt_get_source(&optptr[srrptr-1], rt);
			ip_hdr(skb)->daddr = rt->rt_dst;
			optptr[2] = srrptr+4;
		} else if (net_ratelimit())
			printk(KERN_CRIT "ip_forward(): Argh! Destination lost!\n");
		if (opt->ts_needaddr) {
			optptr = raw + opt->ts;
			ip_rt_get_source(&optptr[optptr[2]-9], 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;
	struct rtable *rt2;
	int err;

	if (!opt->srr)
		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);

		rt = skb->rtable;
		skb->rtable = NULL;
		err = ip_route_input(skb, nexthop, iph->saddr, iph->tos, skb->dev);
		rt2 = skb->rtable;
		if (err || (rt2->rt_type != RTN_UNICAST && rt2->rt_type != RTN_LOCAL)) {
			ip_rt_put(rt2);
			skb->rtable = rt;
			return -EINVAL;
		}
		ip_rt_put(rt);
		if (rt2->rt_type != RTN_LOCAL)
			break;
		/* Superfast 8) loopback forward */
		memcpy(&iph->daddr, &optptr[srrptr-1], 4);
		opt->is_changed = 1;
	}
	if (srrptr <= srrspace) {
		opt->srr_is_hit = 1;
		opt->is_changed = 1;
	}
	return 0;
}
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	*
	8	* Version: $Id: ip_options.c,v 1.21 2001/09/01 00:31:50 davem Exp $
	9	*
	10	* Authors: A.N.Kuznetsov
e905a9ed	11	*
1da177e4 LT	12	*/
1da177e4 LT	13
4fc268d2	14	#include <linux/capability.h>
1da177e4 LT	15	#include <linux/module.h>
	16	#include <linux/types.h>
	17	#include <asm/uaccess.h>
	18	#include <linux/skbuff.h>
	19	#include <linux/ip.h>
	20	#include <linux/icmp.h>
	21	#include <linux/netdevice.h>
	22	#include <linux/rtnetlink.h>
	23	#include <net/sock.h>
	24	#include <net/ip.h>
	25	#include <net/icmp.h>
14c85021	26	#include <net/route.h>
11a03f78	27	#include <net/cipso_ipv4.h>
1da177e4	28
e905a9ed	29	/*
1da177e4 LT	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.
	35	*
	36	* daddr is real destination address, next hop is recorded in IP header.
	37	* saddr is address of outgoing interface.
	38	*/
	39
	40	void ip_options_build(struct sk_buff * skb, struct ip_options * opt,
8712f774	41	__be32 daddr, struct rtable *rt, int is_frag)
1da177e4	42	{
d56f90a7	43	unsigned char *iph = skb_network_header(skb);
1da177e4 LT	44
	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);
1da177e4 LT	48
	49	if (opt->srr)
	50	memcpy(iph+opt->srr+iph[opt->srr+1]-4, &daddr, 4);
	51
	52	if (!is_frag) {
	53	if (opt->rr_needaddr)
	54	ip_rt_get_source(iph+opt->rr+iph[opt->rr+2]-5, rt);
	55	if (opt->ts_needaddr)
	56	ip_rt_get_source(iph+opt->ts+iph[opt->ts+2]-9, rt);
	57	if (opt->ts_needtime) {
	58	struct timeval tv;
e25d2ca6	59	__be32 midtime;
1da177e4 LT	60	do_gettimeofday(&tv);
	61	midtime = htonl((tv.tv_sec % 86400) * 1000 + tv.tv_usec / 1000);
	62	memcpy(iph+opt->ts+iph[opt->ts+2]-5, &midtime, 4);
	63	}
	64	return;
	65	}
	66	if (opt->rr) {
	67	memset(iph+opt->rr, IPOPT_NOP, iph[opt->rr+1]);
	68	opt->rr = 0;
	69	opt->rr_needaddr = 0;
	70	}
	71	if (opt->ts) {
	72	memset(iph+opt->ts, IPOPT_NOP, iph[opt->ts+1]);
	73	opt->ts = 0;
	74	opt->ts_needaddr = opt->ts_needtime = 0;
	75	}
	76	}
	77
e905a9ed	78	/*
1da177e4 LT	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.
	83	*
	84	* NOTE: dopt cannot point to skb.
	85	*/
	86
e905a9ed	87	int ip_options_echo(struct ip_options * dopt, struct sk_buff * skb)
1da177e4 LT	88	{
	89	struct ip_options *sopt;
	90	unsigned char sptr, dptr;
	91	int soffset, doffset;
	92	int optlen;
e25d2ca6	93	__be32 daddr;
1da177e4 LT	94
	95	memset(dopt, 0, sizeof(struct ip_options));
	96
1da177e4 LT	97	sopt = &(IPCB(skb)->opt);
	98
	99	if (sopt->optlen == 0) {
	100	dopt->optlen = 0;
	101	return 0;
	102	}
	103
d56f90a7	104	sptr = skb_network_header(skb);
1da177e4 LT	105	dptr = dopt->__data;
1da177e4 LT	106
ee6b9673	107	daddr = skb->rtable->rt_spec_dst;
1da177e4 LT	108
	109	if (sopt->rr) {
	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)
	116	return -EINVAL;
	117	dptr[2] = soffset + 4;
	118	dopt->rr_needaddr = 1;
	119	}
	120	dptr += optlen;
	121	dopt->optlen += optlen;
	122	}
	123	if (sopt->ts) {
	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)
	131	return -EINVAL;
	132	dopt->ts_needaddr = 1;
	133	soffset += 4;
	134	}
	135	if (sopt->ts_needtime) {
	136	if (soffset + 3 > optlen)
	137	return -EINVAL;
	138	if ((dptr[3]&0xF) != IPOPT_TS_PRESPEC) {
	139	dopt->ts_needtime = 1;
	140	soffset += 4;
	141	} else {
	142	dopt->ts_needtime = 0;
	143
	144	if (soffset + 8 <= optlen) {
fd683222	145	__be32 addr;
1da177e4 LT	146
1da177e4 LT	147	memcpy(&addr, sptr+soffset-1, 4);
c346dca1	148	if (inet_addr_type(dev_net(skb->dst->dev), addr) != RTN_LOCAL) {
1da177e4 LT	149	dopt->ts_needtime = 1;
	150	soffset += 8;
	151	}
	152	}
	153	}
	154	}
	155	dptr[2] = soffset;
	156	}
	157	dptr += optlen;
	158	dopt->optlen += optlen;
	159	}
	160	if (sopt->srr) {
	161	unsigned char * start = sptr+sopt->srr;
3ca3c68e	162	__be32 faddr;
1da177e4 LT	163
	164	optlen = start[1];
	165	soffset = start[2];
	166	doffset = 0;
	167	if (soffset > optlen)
	168	soffset = optlen + 1;
	169	soffset -= 4;
	170	if (soffset > 3) {
	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);
	174	/*
	175	* RFC1812 requires to fix illegal source routes.
	176	*/
eddc9ec5 ACM	177	if (memcmp(&ip_hdr(skb)->saddr,
eddc9ec5 ACM	178	&start[soffset + 3], 4) == 0)
1da177e4 LT	179	doffset -= 4;
	180	}
	181	if (doffset > 3) {
	182	memcpy(&start[doffset-1], &daddr, 4);
	183	dopt->faddr = faddr;
	184	dptr[0] = start[0];
	185	dptr[1] = doffset+3;
	186	dptr[2] = 4;
	187	dptr += doffset+3;
	188	dopt->srr = dopt->optlen + sizeof(struct iphdr);
	189	dopt->optlen += doffset+3;
	190	dopt->is_strictroute = sopt->is_strictroute;
	191	}
	192	}
11a03f78 PM	193	if (sopt->cipso) {
	194	optlen = sptr[sopt->cipso+1];
	195	dopt->cipso = dopt->optlen+sizeof(struct iphdr);
	196	memcpy(dptr, sptr+sopt->cipso, optlen);
	197	dptr += optlen;
	198	dopt->optlen += optlen;
	199	}
1da177e4 LT	200	while (dopt->optlen & 3) {
	201	*dptr++ = IPOPT_END;
	202	dopt->optlen++;
	203	}
	204	return 0;
	205	}
	206
	207	/*
	208	* Options "fragmenting", just fill options not
	209	* allowed in fragments with NOOPs.
	210	* Simple and stupid 8), but the most efficient way.
	211	*/
	212
e905a9ed	213	void ip_options_fragment(struct sk_buff * skb)
1da177e4	214	{
d56f90a7	215	unsigned char *optptr = skb_network_header(skb) + sizeof(struct iphdr);
1da177e4 LT	216	struct ip_options * opt = &(IPCB(skb)->opt);
	217	int l = opt->optlen;
	218	int optlen;
	219
	220	while (l > 0) {
	221	switch (*optptr) {
	222	case IPOPT_END:
	223	return;
	224	case IPOPT_NOOP:
	225	l--;
	226	optptr++;
	227	continue;
	228	}
	229	optlen = optptr[1];
	230	if (optlen<2 \|\| optlen>l)
	231	return;
	232	if (!IPOPT_COPIED(*optptr))
	233	memset(optptr, IPOPT_NOOP, optlen);
	234	l -= optlen;
	235	optptr += optlen;
	236	}
	237	opt->ts = 0;
	238	opt->rr = 0;
	239	opt->rr_needaddr = 0;
	240	opt->ts_needaddr = 0;
	241	opt->ts_needtime = 0;
	242	return;
	243	}
	244
	245	/*
	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.
	249	*/
	250
0e6bd4a1 DL	251	int ip_options_compile(struct net *net,
0e6bd4a1 DL	252	struct ip_options * opt, struct sk_buff * skb)
1da177e4 LT	253	{
	254	int l;
	255	unsigned char * iph;
	256	unsigned char * optptr;
	257	int optlen;
	258	unsigned char * pp_ptr = NULL;
22aba383	259	struct rtable *rt = NULL;
1da177e4	260
22aba383 DL	261	if (skb != NULL) {
	262	rt = skb->rtable;
	263	optptr = (unsigned char *)&(ip_hdr(skb)[1]);
	264	} else
10fe7d85	265	optptr = opt->__data;
22aba383	266	iph = optptr - sizeof(struct iphdr);
1da177e4 LT	267
	268	for (l = opt->optlen; l > 0; ) {
	269	switch (*optptr) {
	270	case IPOPT_END:
	271	for (optptr++, l--; l>0; optptr++, l--) {
	272	if (*optptr != IPOPT_END) {
	273	*optptr = IPOPT_END;
	274	opt->is_changed = 1;
	275	}
	276	}
	277	goto eol;
	278	case IPOPT_NOOP:
	279	l--;
	280	optptr++;
	281	continue;
	282	}
	283	optlen = optptr[1];
	284	if (optlen<2 \|\| optlen>l) {
	285	pp_ptr = optptr;
	286	goto error;
	287	}
	288	switch (*optptr) {
	289	case IPOPT_SSRR:
	290	case IPOPT_LSRR:
	291	if (optlen < 3) {
	292	pp_ptr = optptr + 1;
	293	goto error;
	294	}
	295	if (optptr[2] < 4) {
	296	pp_ptr = optptr + 2;
	297	goto error;
	298	}
	299	/* NB: cf RFC-1812 5.2.4.1 */
	300	if (opt->srr) {
	301	pp_ptr = optptr;
	302	goto error;
	303	}
	304	if (!skb) {
	305	if (optptr[2] != 4 \|\| optlen < 7 \|\| ((optlen-3) & 3)) {
	306	pp_ptr = optptr + 1;
	307	goto error;
	308	}
	309	memcpy(&opt->faddr, &optptr[3], 4);
	310	if (optlen > 7)
	311	memmove(&optptr[3], &optptr[7], optlen-7);
	312	}
	313	opt->is_strictroute = (optptr[0] == IPOPT_SSRR);
	314	opt->srr = optptr - iph;
	315	break;
	316	case IPOPT_RR:
	317	if (opt->rr) {
	318	pp_ptr = optptr;
	319	goto error;
	320	}
	321	if (optlen < 3) {
	322	pp_ptr = optptr + 1;
	323	goto error;
	324	}
	325	if (optptr[2] < 4) {
	326	pp_ptr = optptr + 2;
	327	goto error;
	328	}
	329	if (optptr[2] <= optlen) {
	330	if (optptr[2]+3 > optlen) {
331	pp_ptr = optptr + 2;
332	goto error;
333	}
334	if (skb) {
335	memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
336	opt->is_changed = 1;
337	}
338	optptr[2] += 4;
339	opt->rr_needaddr = 1;
340	}
341	opt->rr = optptr - iph;
342	break;
343	case IPOPT_TIMESTAMP:
344	if (opt->ts) {
345	pp_ptr = optptr;
346	goto error;
347	}
348	if (optlen < 4) {
349	pp_ptr = optptr + 1;
350	goto error;
351	}
352	if (optptr[2] < 5) {
353	pp_ptr = optptr + 2;
354	goto error;
355	}
356	if (optptr[2] <= optlen) {
e25d2ca6	357	__be32 *timeptr = NULL;
1da177e4 LT	358	if (optptr[2]+3 > optptr[1]) {
	359	pp_ptr = optptr + 2;
	360	goto error;
	361	}
	362	switch (optptr[3]&0xF) {
	363	case IPOPT_TS_TSONLY:
	364	opt->ts = optptr - iph;
e905a9ed	365	if (skb)
e25d2ca6	366	timeptr = (__be32*)&optptr[optptr[2]-1];
1da177e4 LT	367	opt->ts_needtime = 1;
	368	optptr[2] += 4;
	369	break;
	370	case IPOPT_TS_TSANDADDR:
	371	if (optptr[2]+7 > optptr[1]) {
	372	pp_ptr = optptr + 2;
	373	goto error;
	374	}
	375	opt->ts = optptr - iph;
	376	if (skb) {
	377	memcpy(&optptr[optptr[2]-1], &rt->rt_spec_dst, 4);
e25d2ca6	378	timeptr = (__be32*)&optptr[optptr[2]+3];
1da177e4 LT	379	}
	380	opt->ts_needaddr = 1;
	381	opt->ts_needtime = 1;
	382	optptr[2] += 8;
	383	break;
	384	case IPOPT_TS_PRESPEC:
	385	if (optptr[2]+7 > optptr[1]) {
	386	pp_ptr = optptr + 2;
	387	goto error;
	388	}
	389	opt->ts = optptr - iph;
	390	{
fd683222	391	__be32 addr;
1da177e4	392	memcpy(&addr, &optptr[optptr[2]-1], 4);
0e6bd4a1	393	if (inet_addr_type(net, addr) == RTN_UNICAST)
1da177e4 LT	394	break;
1da177e4 LT	395	if (skb)
e25d2ca6	396	timeptr = (__be32*)&optptr[optptr[2]+3];
1da177e4 LT	397	}
	398	opt->ts_needtime = 1;
	399	optptr[2] += 8;
	400	break;
	401	default:
	402	if (!skb && !capable(CAP_NET_RAW)) {
	403	pp_ptr = optptr + 3;
	404	goto error;
	405	}
	406	break;
	407	}
	408	if (timeptr) {
	409	struct timeval tv;
e25d2ca6	410	__be32 midtime;
1da177e4 LT	411	do_gettimeofday(&tv);
1da177e4 LT	412	midtime = htonl((tv.tv_sec % 86400) * 1000 + tv.tv_usec / 1000);
e25d2ca6	413	memcpy(timeptr, &midtime, sizeof(__be32));
1da177e4 LT	414	opt->is_changed = 1;
	415	}
	416	} else {
	417	unsigned overflow = optptr[3]>>4;
	418	if (overflow == 15) {
	419	pp_ptr = optptr + 3;
	420	goto error;
	421	}
	422	opt->ts = optptr - iph;
	423	if (skb) {
	424	optptr[3] = (optptr[3]&0xF)\|((overflow+1)<<4);
	425	opt->is_changed = 1;
	426	}
	427	}
	428	break;
	429	case IPOPT_RA:
	430	if (optlen < 4) {
	431	pp_ptr = optptr + 1;
	432	goto error;
	433	}
	434	if (optptr[2] == 0 && optptr[3] == 0)
	435	opt->router_alert = optptr - iph;
	436	break;
11a03f78	437	case IPOPT_CIPSO:
f8687afe	438	if ((!skb && !capable(CAP_NET_RAW)) \|\| opt->cipso) {
11a03f78 PM	439	pp_ptr = optptr;
	440	goto error;
	441	}
	442	opt->cipso = optptr - iph;
e905a9ed	443	if (cipso_v4_validate(&optptr)) {
11a03f78 PM	444	pp_ptr = optptr;
	445	goto error;
	446	}
	447	break;
1da177e4 LT	448	case IPOPT_SEC:
	449	case IPOPT_SID:
	450	default:
	451	if (!skb && !capable(CAP_NET_RAW)) {
	452	pp_ptr = optptr;
	453	goto error;
	454	}
	455	break;
	456	}
	457	l -= optlen;
	458	optptr += optlen;
	459	}
	460
	461	eol:
	462	if (!pp_ptr)
	463	return 0;
	464
	465	error:
	466	if (skb) {
	467	icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl((pp_ptr-iph)<<24));
	468	}
	469	return -EINVAL;
	470	}
	471
	472
	473	/*
	474	* Undo all the changes done by ip_options_compile().
	475	*/
	476
	477	void ip_options_undo(struct ip_options * opt)
	478	{
	479	if (opt->srr) {
	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);
	483	}
	484	if (opt->rr_needaddr) {
	485	unsigned char * optptr = opt->__data+opt->rr-sizeof(struct iphdr);
	486	optptr[2] -= 4;
	487	memset(&optptr[optptr[2]-1], 0, 4);
	488	}
	489	if (opt->ts) {
	490	unsigned char * optptr = opt->__data+opt->ts-sizeof(struct iphdr);
	491	if (opt->ts_needtime) {
	492	optptr[2] -= 4;
	493	memset(&optptr[optptr[2]-1], 0, 4);
	494	if ((optptr[3]&0xF) == IPOPT_TS_PRESPEC)
	495	optptr[2] -= 4;
	496	}
	497	if (opt->ts_needaddr) {
	498	optptr[2] -= 4;
	499	memset(&optptr[optptr[2]-1], 0, 4);
	500	}
	501	}
	502	}
	503
4c6ea29d	504	static struct ip_options *ip_options_get_alloc(const int optlen)
1da177e4	505	{
37640703 MK	506	return kzalloc(sizeof(struct ip_options) + ((optlen + 3) & ~3),
37640703 MK	507	GFP_KERNEL);
4c6ea29d	508	}
1da177e4	509
f2c4802b	510	static int ip_options_get_finish(struct net net, struct ip_options *optp,
4c6ea29d ACM	511	struct ip_options *opt, int optlen)
4c6ea29d ACM	512	{
1da177e4 LT	513	while (optlen & 3)
	514	opt->__data[optlen++] = IPOPT_END;
	515	opt->optlen = optlen;
f2c4802b	516	if (optlen && ip_options_compile(net, opt, NULL)) {
1da177e4 LT	517	kfree(opt);
	518	return -EINVAL;
	519	}
a51482bd	520	kfree(*optp);
1da177e4 LT	521	*optp = opt;
	522	return 0;
	523	}
	524
f2c4802b DL	525	int ip_options_get_from_user(struct net net, struct ip_options *optp,
f2c4802b DL	526	unsigned char __user *data, int optlen)
4c6ea29d ACM	527	{
	528	struct ip_options *opt = ip_options_get_alloc(optlen);
	529
	530	if (!opt)
	531	return -ENOMEM;
	532	if (optlen && copy_from_user(opt->__data, data, optlen)) {
	533	kfree(opt);
	534	return -EFAULT;
	535	}
f2c4802b	536	return ip_options_get_finish(net, optp, opt, optlen);
4c6ea29d ACM	537	}
4c6ea29d ACM	538
f2c4802b DL	539	int ip_options_get(struct net net, struct ip_options *optp,
f2c4802b DL	540	unsigned char *data, int optlen)
4c6ea29d ACM	541	{
	542	struct ip_options *opt = ip_options_get_alloc(optlen);
	543
	544	if (!opt)
	545	return -ENOMEM;
	546	if (optlen)
	547	memcpy(opt->__data, data, optlen);
f2c4802b	548	return ip_options_get_finish(net, optp, opt, optlen);
4c6ea29d ACM	549	}
4c6ea29d ACM	550
1da177e4 LT	551	void ip_forward_options(struct sk_buff *skb)
	552	{
	553	struct ip_options * opt = &(IPCB(skb)->opt);
	554	unsigned char * optptr;
ee6b9673	555	struct rtable *rt = skb->rtable;
d56f90a7	556	unsigned char *raw = skb_network_header(skb);
1da177e4 LT	557
	558	if (opt->rr_needaddr) {
	559	optptr = (unsigned char *)raw + opt->rr;
	560	ip_rt_get_source(&optptr[optptr[2]-5], rt);
	561	opt->is_changed = 1;
	562	}
	563	if (opt->srr_is_hit) {
	564	int srrptr, srrspace;
	565
	566	optptr = raw + opt->srr;
	567
	568	for ( srrptr=optptr[2], srrspace = optptr[1];
	569	srrptr <= srrspace;
	570	srrptr += 4
	571	) {
	572	if (srrptr + 3 > srrspace)
	573	break;
	574	if (memcmp(&rt->rt_dst, &optptr[srrptr-1], 4) == 0)
	575	break;
	576	}
	577	if (srrptr + 3 <= srrspace) {
	578	opt->is_changed = 1;
	579	ip_rt_get_source(&optptr[srrptr-1], rt);
eddc9ec5	580	ip_hdr(skb)->daddr = rt->rt_dst;
1da177e4 LT	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);
	587	opt->is_changed = 1;
	588	}
	589	}
	590	if (opt->is_changed) {
	591	opt->is_changed = 0;
eddc9ec5	592	ip_send_check(ip_hdr(skb));
1da177e4 LT	593	}
	594	}
	595
	596	int ip_options_rcv_srr(struct sk_buff *skb)
	597	{
	598	struct ip_options *opt = &(IPCB(skb)->opt);
	599	int srrspace, srrptr;
9e12bb22	600	__be32 nexthop;
eddc9ec5	601	struct iphdr *iph = ip_hdr(skb);
d56f90a7	602	unsigned char *optptr = skb_network_header(skb) + opt->srr;
ee6b9673	603	struct rtable *rt = skb->rtable;
1da177e4 LT	604	struct rtable *rt2;
	605	int err;
	606
	607	if (!opt->srr)
	608	return 0;
	609
	610	if (skb->pkt_type != PACKET_HOST)
	611	return -EINVAL;
	612	if (rt->rt_type == RTN_UNICAST) {
	613	if (!opt->is_strictroute)
	614	return 0;
	615	icmp_send(skb, ICMP_PARAMETERPROB, 0, htonl(16<<24));
	616	return -EINVAL;
	617	}
	618	if (rt->rt_type != RTN_LOCAL)
	619	return -EINVAL;
	620
	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));
	624	return -EINVAL;
	625	}
	626	memcpy(&nexthop, &optptr[srrptr-1], 4);
	627
ee6b9673 ED	628	rt = skb->rtable;
ee6b9673 ED	629	skb->rtable = NULL;
1da177e4	630	err = ip_route_input(skb, nexthop, iph->saddr, iph->tos, skb->dev);
ee6b9673	631	rt2 = skb->rtable;
1da177e4 LT	632	if (err \|\| (rt2->rt_type != RTN_UNICAST && rt2->rt_type != RTN_LOCAL)) {
1da177e4 LT	633	ip_rt_put(rt2);
ee6b9673	634	skb->rtable = rt;
1da177e4 LT	635	return -EINVAL;
	636	}
	637	ip_rt_put(rt);
	638	if (rt2->rt_type != RTN_LOCAL)
	639	break;
	640	/* Superfast 8) loopback forward */
	641	memcpy(&iph->daddr, &optptr[srrptr-1], 4);
	642	opt->is_changed = 1;
	643	}
	644	if (srrptr <= srrspace) {
	645	opt->srr_is_hit = 1;
	646	opt->is_changed = 1;
	647	}
	648	return 0;
	649	}