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/* $OpenBSD: route_src.c,v 1.1 2004/06/06 16:49:09 cedric Exp $ */
/*
* Copyright (c) 2004 Cedric Berger <cedric@berger.to>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/systm.h>
#include <sys/socket.h>
#include <net/route.h>
#include <netinet/in.h>
void mask_set(void *, struct sockaddr *, int, int);
struct sockaddr *mask_trim(struct sockaddr *, int, int);
/*
* verify that the netmask is NULL or has all 1s for the destination part.
* setup a corrected mask otherwise.
*/
void
sroute_verify_host(struct rt_addrinfo *ai)
{
static struct sockaddr_rtin netmask4;
if (ai->rti_info[RTAX_NETMASK] == NULL)
return; /* no mask is a host mask */
if (ai->rti_info[RTAX_DST]->sa_family == AF_INET)
goto _inet;
/* just clear the netmask */
ai->rti_info[RTAX_NETMASK] = NULL;
return;
_inet:
if (satortin(ai->rti_info[RTAX_NETMASK])->rtin_dst.s_addr ==
(in_addr_t)-1)
return; /* all 1s is a host mask */
netmask4.rtin_dst.s_addr = (in_addr_t)-1;
netmask4.rtin_src = satortin(ai->rti_info[RTAX_NETMASK])->rtin_src;
ai->rti_info[RTAX_NETMASK] = mask_trim(sintosa(&netmask4),
offsetof(struct sockaddr_rtin, rtin_dst), 8);
}
/*
* set the netmask of a cloned route. take the source part of the
* old mask and use the genmask (or NULL) for the destination part.
*/
void
sroute_clone_route(struct rt_addrinfo *ai, struct sockaddr *oldmask,
struct sockaddr *genmask)
{
if (ai->rti_info[RTAX_DST]->sa_family == AF_INET)
goto _inet;
if ((ai->rti_info[RTAX_NETMASK] = genmask) == NULL)
ai->rti_flags |= RTF_HOST;
return;
_inet:
ai->rti_info[RTAX_NETMASK] = sroute_clone_mask4(oldmask, genmask);
if (ai->rti_info[RTAX_NETMASK] == NULL || satortin(
ai->rti_info[RTAX_NETMASK])->rtin_dst.s_addr == (in_addr_t)-1)
ai->rti_flags |= RTF_HOST;
}
/*
* get the netmask of an IPv4 cloned route. take the source part of the
* old mask and use the genmask (or NULL) for the destination part.
*/
struct sockaddr *
sroute_clone_mask4(struct sockaddr *oldmask, struct sockaddr *genmask)
{
static struct sockaddr_rtin netmask4;
mask_set(&netmask4.rtin_dst, genmask,
offsetof(struct sockaddr_in, sin_addr), 4);
mask_set(&netmask4.rtin_src, oldmask,
offsetof(struct sockaddr_rtin, rtin_src), 4);
return mask_trim(sintosa(&netmask4),
offsetof(struct sockaddr_rtin, rtin_dst), 8);
}
/*
* userland provides RTAX_SRC and RTAX_SRCMASK entries, but the kernel wants
* that info packed inside RTAX_DST and RTAX_NETMASK themselves.
*/
void
sroute_compact(struct rt_addrinfo *ai, int type)
{
static struct sockaddr_rtin dst4 = { sizeof(dst4), AF_INET };
static struct sockaddr_rtin netmask4;
if (ai->rti_info[RTAX_DST]->sa_family == AF_INET)
goto _inet;
return;
_inet:
dst4.rtin_dst = satosin(ai->rti_info[RTAX_DST])->sin_addr;
mask_set(&netmask4.rtin_dst, ai->rti_info[RTAX_NETMASK],
offsetof(struct sockaddr_in, sin_addr), 4);
if (ai->rti_info[RTAX_SRC] != NULL) {
dst4.rtin_src = satosin(ai->rti_info[RTAX_SRC])->sin_addr;
mask_set(&netmask4.rtin_src, ai->rti_info[RTAX_SRCMASK],
offsetof(struct sockaddr_in, sin_addr), 4);
} else
dst4.rtin_src.s_addr = netmask4.rtin_src.s_addr = 0;
ai->rti_info[RTAX_DST] = (struct sockaddr *)&dst4;
/*
* do not generate a netmask artificially for RTM_GET or it
* will break the loose-matching behaviour that is expected.
*/
if (type != RTM_GET || ai->rti_info[RTAX_NETMASK] != NULL ||
ai->rti_info[RTAX_SRCMASK] != NULL)
ai->rti_info[RTAX_NETMASK] = mask_trim(sintosa(&netmask4),
offsetof(struct sockaddr_rtin, rtin_dst), 8);
}
/*
* opposite of sroute_compact, when sending a routing message to userland.
*/
void
sroute_expand(struct rt_addrinfo *ai)
{
static struct sockaddr_in dst4 = { sizeof(dst4), AF_INET };
static struct sockaddr_in src4 = { sizeof(src4), AF_INET };
static struct sockaddr_in netmask4, srcmask4;
if (ai->rti_info[RTAX_DST]->sa_family == AF_INET)
goto _inet;
return;
_inet:
dst4.sin_addr = satortin(ai->rti_info[RTAX_DST])->rtin_dst;
src4.sin_addr = satortin(ai->rti_info[RTAX_DST])->rtin_src;
ai->rti_info[RTAX_DST] = sintosa(&dst4);
ai->rti_info[RTAX_SRC] = sintosa(&src4);
mask_set(&netmask4.sin_addr, ai->rti_info[RTAX_NETMASK],
offsetof(struct sockaddr_rtin, rtin_dst), 4);
mask_set(&srcmask4.sin_addr, ai->rti_info[RTAX_NETMASK],
offsetof(struct sockaddr_rtin, rtin_src), 4);
ai->rti_info[RTAX_NETMASK] = mask_trim(sintosa(&netmask4),
offsetof(struct sockaddr_in, sin_addr), 4);
ai->rti_info[RTAX_SRCMASK] = mask_trim(sintosa(&srcmask4),
offsetof(struct sockaddr_in, sin_addr), 4);
if (!src4.sin_addr.s_addr && !srcmask4.sin_addr.s_addr) {
ai->rti_info[RTAX_SRC] = NULL;
ai->rti_info[RTAX_SRCMASK] = NULL;
}
}
/*
* set a netmask from a potentially NULL or truncated mask.
*/
void
mask_set(void *mask, struct sockaddr *sa, int off, int sz)
{
int i, len = off + sz;
if (sa == NULL) {
memset(mask, -1, sz);
return;
}
bzero(mask, sz);
for (i = off; i < len; i++) {
if (i >= sa->sa_len)
break;
*((char *)mask)++ = ((char *)sa)[i];
}
}
/*
* set length and trim unused bytes from a netmask.
* return NULL if the mask is all 1s (host route)
*/
struct sockaddr *
mask_trim(struct sockaddr *sa, int off, int sz)
{
int i, len = off + sz;
if (sa == NULL)
return (NULL);
for (i = len; i > 1 && ((char *)sa)[i-1] == 0; i--)
;
sa->sa_len = i;
if (i < len)
return (sa);
for (i = off; i < len; i++)
if (((char *)sa)[i] != (char)-1)
break;
return ((i < len) ? sa : NULL);
}
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