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linux/net/ipv4/ip_options.c
Arnaldo Carvalho de Melo 14c850212e [INET_SOCK]: Move struct inet_sock & helper functions to net/inet_sock.h 
To help in reducing the number of include dependencies, several files were
touched as they were getting needed headers indirectly for stuff they use.

Thanks also to Alan Menegotto for pointing out that net/dccp/proto.c had
linux/dccp.h include twice.

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2006-01-03 13:11:21 -08:00

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/*
* 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/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>
/*
* 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,
u32 daddr, struct rtable *rt, int is_frag)
{
unsigned char * iph = skb->nh.raw;
memcpy(&(IPCB(skb)->opt), opt, sizeof(struct ip_options));
memcpy(iph+sizeof(struct iphdr), opt->__data, opt->optlen);
opt = &(IPCB(skb)->opt);
opt->is_data = 0;
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;
__u32 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;
u32 daddr;
memset(dopt, 0, sizeof(struct ip_options));
dopt->is_data = 1;
sopt = &(IPCB(skb)->opt);
if (sopt->optlen == 0) {
dopt->optlen = 0;
return 0;
}
sptr = skb->nh.raw;
dptr = dopt->__data;
if (skb->dst)
daddr = ((struct rtable*)skb->dst)->rt_spec_dst;
else
daddr = skb->nh.iph->daddr;
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) {
__u32 addr;
memcpy(&addr, sptr+soffset-1, 4);
if (inet_addr_type(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;
u32 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(&skb->nh.iph->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;
}
}
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->nh.raw;
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 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 = skb ? (struct rtable*)skb->dst : NULL;
if (!opt) {
opt = &(IPCB(skb)->opt);
memset(opt, 0, sizeof(struct ip_options));
iph = skb->nh.raw;
opt->optlen = ((struct iphdr *)iph)->ihl*4 - sizeof(struct iphdr);
optptr = iph + sizeof(struct iphdr);
opt->is_data = 0;
} else {
optptr = opt->is_data ? opt->__data : (unsigned char*)&(skb->nh.iph[1]);
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) {
__u32 * 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 = (__u32*)&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 = (__u32*)&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;
{
u32 addr;
memcpy(&addr, &optptr[optptr[2]-1], 4);
if (inet_addr_type(addr) == RTN_UNICAST)
break;
if (skb)
timeptr = (__u32*)&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;
__u32 midtime;
do_gettimeofday(&tv);
midtime = htonl((tv.tv_sec % 86400) * 1000 + tv.tv_usec / 1000);
memcpy(timeptr, &midtime, sizeof(__u32));
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_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)
{
struct ip_options *opt = kmalloc(sizeof(*opt) + ((optlen + 3) & ~3),
GFP_KERNEL);
if (opt)
memset(opt, 0, sizeof(*opt));
return opt;
}
static int ip_options_get_finish(struct ip_options **optp,
struct ip_options *opt, int optlen)
{
while (optlen & 3)
opt->__data[optlen++] = IPOPT_END;
opt->optlen = optlen;
opt->is_data = 1;
opt->is_setbyuser = 1;
if (optlen && ip_options_compile(opt, NULL)) {
kfree(opt);
return -EINVAL;
}
kfree(*optp);
*optp = opt;
return 0;
}
int ip_options_get_from_user(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(optp, opt, optlen);
}
int ip_options_get(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(optp, opt, optlen);
}
void ip_forward_options(struct sk_buff *skb)
{
struct ip_options * opt = &(IPCB(skb)->opt);
unsigned char * optptr;
struct rtable *rt = (struct rtable*)skb->dst;
unsigned char *raw = skb->nh.raw;
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);
skb->nh.iph->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(skb->nh.iph);
}
}
int ip_options_rcv_srr(struct sk_buff *skb)
{
struct ip_options *opt = &(IPCB(skb)->opt);
int srrspace, srrptr;
u32 nexthop;
struct iphdr *iph = skb->nh.iph;
unsigned char * optptr = skb->nh.raw + opt->srr;
struct rtable *rt = (struct rtable*)skb->dst;
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 = (struct rtable*)skb->dst;
skb->dst = NULL;
err = ip_route_input(skb, nexthop, iph->saddr, iph->tos, skb->dev);
rt2 = (struct rtable*)skb->dst;
if (err || (rt2->rt_type != RTN_UNICAST && rt2->rt_type != RTN_LOCAL)) {
ip_rt_put(rt2);
skb->dst = &rt->u.dst;
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;
}
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