/*-
* Copyright 2005, Gleb Smirnoff <glebius@FreeBSD.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/ctype.h>
#include <sys/errno.h>
#include <sys/rwlock.h>
#include <sys/socket.h>
#include <sys/syslog.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip_fw.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netgraph/ng_message.h>
#include <netgraph/ng_parse.h>
#include <netgraph/ng_ipfw.h>
#include <netgraph/netgraph.h>
static int ng_ipfw_mod_event(module_t mod, int event, void *data);
static ng_constructor_t ng_ipfw_constructor;
static ng_shutdown_t ng_ipfw_shutdown;
static ng_newhook_t ng_ipfw_newhook;
static ng_connect_t ng_ipfw_connect;
static ng_findhook_t ng_ipfw_findhook;
static ng_rcvdata_t ng_ipfw_rcvdata;
static ng_disconnect_t ng_ipfw_disconnect;
static hook_p ng_ipfw_findhook1(node_p, u_int16_t );
static int ng_ipfw_input(struct mbuf **, int, struct ip_fw_args *,
int);
/* We have only one node */
static node_p fw_node;
/* Netgraph node type descriptor */
static struct ng_type ng_ipfw_typestruct = {
.version = NG_ABI_VERSION,
.name = NG_IPFW_NODE_TYPE,
.mod_event = ng_ipfw_mod_event,
.constructor = ng_ipfw_constructor,
.shutdown = ng_ipfw_shutdown,
.newhook = ng_ipfw_newhook,
.connect = ng_ipfw_connect,
.findhook = ng_ipfw_findhook,
.rcvdata = ng_ipfw_rcvdata,
.disconnect = ng_ipfw_disconnect,
};
NETGRAPH_INIT(ipfw, &ng_ipfw_typestruct);
MODULE_DEPEND(ng_ipfw, ipfw, 2, 2, 2);
/* Information we store for each hook */
struct ng_ipfw_hook_priv {
hook_p hook;
u_int16_t rulenum;
};
typedef struct ng_ipfw_hook_priv *hpriv_p;
static int
ng_ipfw_mod_event(module_t mod, int event, void *data)
{
int error = 0;
switch (event) {
case MOD_LOAD:
if (ng_ipfw_input_p != NULL) {
error = EEXIST;
break;
}
/* Setup node without any private data */
if ((error = ng_make_node_common(&ng_ipfw_typestruct, &fw_node))
!= 0) {
log(LOG_ERR, "%s: can't create ng_ipfw node", __func__);
break;
};
/* Try to name node */
if (ng_name_node(fw_node, "ipfw") != 0)
log(LOG_WARNING, "%s: failed to name node \"ipfw\"",
__func__);
/* Register hook */
ng_ipfw_input_p = ng_ipfw_input;
break;
case MOD_UNLOAD:
/*
* This won't happen if a node exists.
* ng_ipfw_input_p is already cleared.
*/
break;
default:
error = EOPNOTSUPP;
break;
}
return (error);
}
static int
ng_ipfw_constructor(node_p node)
{
return (EINVAL); /* Only one node */
}
static int
ng_ipfw_newhook(node_p node, hook_p hook, const char *name)
{
hpriv_p hpriv;
u_int16_t rulenum;
const char *cp;
char *endptr;
/* Protect from leading zero */
if (name[0] == '0' && name[1] != '\0')
return (EINVAL);
/* Check that name contains only digits */
for (cp = name; *cp != '\0'; cp++)
if (!isdigit(*cp))
return (EINVAL);
/* Convert it to integer */
rulenum = (u_int16_t)strtol(name, &endptr, 10);
if (*endptr != '\0')
return (EINVAL);
/* Allocate memory for this hook's private data */
hpriv = malloc(sizeof(*hpriv), M_NETGRAPH, M_NOWAIT | M_ZERO);
if (hpriv== NULL)
return (ENOMEM);
hpriv->hook = hook;
hpriv->rulenum = rulenum;
NG_HOOK_SET_PRIVATE(hook, hpriv);
return(0);
}
/*
* Set hooks into queueing mode, to avoid recursion between
* netgraph layer and ip_{input,output}.
*/
static int
ng_ipfw_connect(hook_p hook)
{
NG_HOOK_FORCE_QUEUE(hook);
return (0);
}
/* Look up hook by name */
hook_p
ng_ipfw_findhook(node_p node, const char *name)
{
u_int16_t n; /* numeric representation of hook */
char *endptr;
n = (u_int16_t)strtol(name, &endptr, 10);
if (*endptr != '\0')
return NULL;
return ng_ipfw_findhook1(node, n);
}
/* Look up hook by rule number */
static hook_p
ng_ipfw_findhook1(node_p node, u_int16_t rulenum)
{
hook_p hook;
hpriv_p hpriv;
LIST_FOREACH(hook, &node->nd_hooks, hk_hooks) {
hpriv = NG_HOOK_PRIVATE(hook);
if (NG_HOOK_IS_VALID(hook) && (hpriv->rulenum == rulenum))
return (hook);
}
return (NULL);
}
static int
ng_ipfw_rcvdata(hook_p hook, item_p item)
{
struct ng_ipfw_tag *ngit;
struct mbuf *m;
NGI_GET_M(item, m);
NG_FREE_ITEM(item);
if ((ngit = (struct ng_ipfw_tag *)m_tag_locate(m, NGM_IPFW_COOKIE, 0,
NULL)) == NULL) {
NG_FREE_M(m);
return (EINVAL); /* XXX: find smth better */
};
switch (ngit->dir) {
case NG_IPFW_OUT:
{
struct ip *ip;
if (m->m_len < sizeof(struct ip) &&
(m = m_pullup(m, sizeof(struct ip))) == NULL)
return (EINVAL);
ip = mtod(m, struct ip *);
ip->ip_len = ntohs(ip->ip_len);
ip->ip_off = ntohs(ip->ip_off);
return ip_output(m, NULL, NULL, IP_FORWARDING, NULL, NULL);
}
case NG_IPFW_IN:
ip_input(m);
return (0);
default:
panic("ng_ipfw_rcvdata: bad dir %u", ngit->dir);
}
/* not reached */
return (0);
}
static int
ng_ipfw_input(struct mbuf **m0, int dir, struct ip_fw_args *fwa, int tee)
{
struct mbuf *m;
struct ng_ipfw_tag *ngit;
struct ip *ip;
hook_p hook;
int error = 0;
/*
* Node must be loaded and corresponding hook must be present.
*/
if (fw_node == NULL ||
(hook = ng_ipfw_findhook1(fw_node, fwa->cookie)) == NULL) {
if (tee == 0)
m_freem(*m0);
return (ESRCH); /* no hook associated with this rule */
}
/*
* We have two modes: in normal mode we add a tag to packet, which is
* important to return packet back to IP stack. In tee mode we make
* a copy of a packet and forward it into netgraph without a tag.
*/
if (tee == 0) {
m = *m0;
*m0 = NULL; /* it belongs now to netgraph */
if ((ngit = (struct ng_ipfw_tag *)m_tag_alloc(NGM_IPFW_COOKIE,
0, TAGSIZ, M_NOWAIT|M_ZERO)) == NULL) {
m_freem(m);
return (ENOMEM);
}
ngit->rule = fwa->rule;
ngit->dir = dir;
ngit->ifp = fwa->oif;
m_tag_prepend(m, &ngit->mt);
} else
if ((m = m_dup(*m0, M_DONTWAIT)) == NULL)
return (ENOMEM); /* which is ignored */
if (m->m_len < sizeof(struct ip) &&
(m = m_pullup(m, sizeof(struct ip))) == NULL)
return (EINVAL);
ip = mtod(m, struct ip *);
ip->ip_len = htons(ip->ip_len);
ip->ip_off = htons(ip->ip_off);
NG_SEND_DATA_ONLY(error, hook, m);
return (error);
}
static int
ng_ipfw_shutdown(node_p node)
{
/*
* After our single node has been removed,
* the only thing that can be done is
* 'kldunload ng_ipfw.ko'
*/
ng_ipfw_input_p = NULL;
NG_NODE_UNREF(node);
return (0);
}
static int
ng_ipfw_disconnect(hook_p hook)
{
const hpriv_p hpriv = NG_HOOK_PRIVATE(hook);
free(hpriv, M_NETGRAPH);
NG_HOOK_SET_PRIVATE(hook, NULL);
return (0);
}
