/*
* 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
*
*/
#include <linux/types.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/icmp.h>
#include <linux/netdevice.h>
#include <net/sock.h>
#include <net/ip.h>
#include <net/icmp.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.
*/
void ip_options_build(struct sk_buff * skb, struct options * opt,
__u32 daddr, __u32 saddr,
int is_frag)
{
unsigned char * iph = (unsigned char*)skb->ip_hdr;
memcpy(skb->proto_priv, opt, sizeof(struct options));
memcpy(iph+sizeof(struct iphdr), opt->__data, opt->optlen);
opt = (struct options*)skb->proto_priv;
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)
memcpy(iph+opt->rr+iph[opt->rr+2]-5, &saddr, 4);
if (opt->ts_needaddr)
memcpy(iph+opt->ts+iph[opt->ts+2]-9, &saddr, 4);
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;
}
}
int ip_options_echo(struct options * dopt, struct options * sopt,
__u32 daddr, __u32 saddr,
struct sk_buff * skb)
{
unsigned char *sptr, *dptr;
int soffset, doffset;
int optlen;
memset(dopt, 0, sizeof(struct options));
dopt->is_data = 1;
if (!sopt)
sopt = (struct options*)skb->proto_priv;
if (sopt->optlen == 0)
{
dopt->optlen = 0;
return 0;
}
sptr = (sopt->is_data ? sopt->__data - sizeof(struct iphdr) :
(unsigned char *)skb->ip_hdr);
dptr = dopt->__data;
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;
dopt->ts_needtime = 1;
soffset += 4;
}
if (((struct timestamp*)(dptr+1))->flags == IPOPT_TS_PRESPEC)
{
__u32 addr;
memcpy(&addr, sptr+soffset-9, 4);
if (ip_chk_addr(addr) == 0)
{
dopt->ts_needtime = 0;
dopt->ts_needaddr = 0;
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(&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;
}
void ip_options_fragment(struct sk_buff * skb)
{
unsigned char * optptr = (unsigned char*)skb->ip_hdr;
struct options * opt = (struct options*)skb->proto_priv;
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 (!(*optptr & 0x80))
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 options * opt, struct sk_buff * skb)
{
int l;
unsigned char * iph;
unsigned char * optptr;
int optlen;
unsigned char * pp_ptr = NULL;
if (!opt)
{
opt = (struct options*)skb->proto_priv;
memset(opt, 0, sizeof(struct options));
iph = (unsigned char*)skb->ip_hdr;
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->ip_hdr[1];
iph = optptr - sizeof(struct iphdr);
}
for (l = opt->optlen; l > 0; )
{
switch (*optptr)
{
case IPOPT_END:
for (optptr++, l--; l>0; 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], &skb->dev->pa_addr, 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)
{
struct timestamp * ts = (struct timestamp*)(optptr+1);
__u32 * timeptr = NULL;
if (ts->ptr+3 > ts->len)
{
pp_ptr = optptr + 2;
goto error;
}
switch (ts->flags)
{
case IPOPT_TS_TSONLY:
opt->ts = optptr - iph;
if (skb)
timeptr = (__u32*)&optptr[ts->ptr-1];
opt->ts_needtime = 1;
ts->ptr += 4;
break;
case IPOPT_TS_TSANDADDR:
if (ts->ptr+7 > ts->len)
{
pp_ptr = optptr + 2;
goto error;
}
opt->ts = optptr - iph;
if (skb)
{
memcpy(&optptr[ts->ptr-1], &skb->dev->pa_addr, 4);
timeptr = (__u32*)&optptr[ts->ptr+3];
}
opt->ts_needaddr = 1;
opt->ts_needtime = 1;
ts->ptr += 8;
break;
case IPOPT_TS_PRESPEC:
if (ts->ptr+7 > ts->len)
{
pp_ptr = optptr + 2;
goto error;
}
opt->ts = optptr - iph;
{
__u32 addr;
memcpy(&addr, &optptr[ts->ptr-1], 4);
if (ip_chk_addr(addr) == 0)
break;
if (skb)
timeptr = (__u32*)&optptr[ts->ptr+3];
}
opt->ts_needaddr = 1;
opt->ts_needtime = 1;
ts->ptr += 8;
break;
default:
pp_ptr = optptr + 3;
goto error;
}
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
{
struct timestamp * ts = (struct timestamp*)(optptr+1);
if (ts->overflow == 15)
{
pp_ptr = optptr + 3;
goto error;
}
opt->ts = optptr - iph;
if (skb)
{
ts->overflow++;
opt->is_changed = 1;
}
}
break;
case IPOPT_SEC:
case IPOPT_SID:
default:
if (!skb)
{
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, pp_ptr-iph, skb->dev);
kfree_skb(skb, FREE_READ);
}
return -EINVAL;
}
