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FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //sys/amd64/compile/hs32/modules/usr/src/sys/modules/pccard/@/netinet/ipfw/ip_fw_nat.c |
/*-
* Copyright (c) 2008 Paolo Pisati
* 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: release/9.1.0/sys/netinet/ipfw/ip_fw_nat.c 232171 2012-02-26 10:20:13Z ae $");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/eventhandler.h>
#include <sys/malloc.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/module.h>
#include <sys/rwlock.h>
#define IPFW_INTERNAL /* Access to protected data structures in ip_fw.h. */
#include <netinet/libalias/alias.h>
#include <netinet/libalias/alias_local.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/ip_fw.h>
#include <netinet/ipfw/ip_fw_private.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>
#include <machine/in_cksum.h> /* XXX for in_cksum */
static VNET_DEFINE(eventhandler_tag, ifaddr_event_tag);
#define V_ifaddr_event_tag VNET(ifaddr_event_tag)
static void
ifaddr_change(void *arg __unused, struct ifnet *ifp)
{
struct cfg_nat *ptr;
struct ifaddr *ifa;
struct ip_fw_chain *chain;
chain = &V_layer3_chain;
IPFW_WLOCK(chain);
/* Check every nat entry... */
LIST_FOREACH(ptr, &chain->nat, _next) {
/* ...using nic 'ifp->if_xname' as dynamic alias address. */
if (strncmp(ptr->if_name, ifp->if_xname, IF_NAMESIZE) != 0)
continue;
if_addr_rlock(ifp);
TAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
if (ifa->ifa_addr == NULL)
continue;
if (ifa->ifa_addr->sa_family != AF_INET)
continue;
ptr->ip = ((struct sockaddr_in *)
(ifa->ifa_addr))->sin_addr;
LibAliasSetAddress(ptr->lib, ptr->ip);
}
if_addr_runlock(ifp);
}
IPFW_WUNLOCK(chain);
}
/*
* delete the pointers for nat entry ix, or all of them if ix < 0
*/
static void
flush_nat_ptrs(struct ip_fw_chain *chain, const int ix)
{
int i;
ipfw_insn_nat *cmd;
IPFW_WLOCK_ASSERT(chain);
for (i = 0; i < chain->n_rules; i++) {
cmd = (ipfw_insn_nat *)ACTION_PTR(chain->map[i]);
/* XXX skip log and the like ? */
if (cmd->o.opcode == O_NAT && cmd->nat != NULL &&
(ix < 0 || cmd->nat->id == ix))
cmd->nat = NULL;
}
}
static void
del_redir_spool_cfg(struct cfg_nat *n, struct redir_chain *head)
{
struct cfg_redir *r, *tmp_r;
struct cfg_spool *s, *tmp_s;
int i, num;
LIST_FOREACH_SAFE(r, head, _next, tmp_r) {
num = 1; /* Number of alias_link to delete. */
switch (r->mode) {
case REDIR_PORT:
num = r->pport_cnt;
/* FALLTHROUGH */
case REDIR_ADDR:
case REDIR_PROTO:
/* Delete all libalias redirect entry. */
for (i = 0; i < num; i++)
LibAliasRedirectDelete(n->lib, r->alink[i]);
/* Del spool cfg if any. */
LIST_FOREACH_SAFE(s, &r->spool_chain, _next, tmp_s) {
LIST_REMOVE(s, _next);
free(s, M_IPFW);
}
free(r->alink, M_IPFW);
LIST_REMOVE(r, _next);
free(r, M_IPFW);
break;
default:
printf("unknown redirect mode: %u\n", r->mode);
/* XXX - panic?!?!? */
break;
}
}
}
static void
add_redir_spool_cfg(char *buf, struct cfg_nat *ptr)
{
struct cfg_redir *r, *ser_r;
struct cfg_spool *s, *ser_s;
int cnt, off, i;
for (cnt = 0, off = 0; cnt < ptr->redir_cnt; cnt++) {
ser_r = (struct cfg_redir *)&buf[off];
r = malloc(SOF_REDIR, M_IPFW, M_WAITOK | M_ZERO);
memcpy(r, ser_r, SOF_REDIR);
LIST_INIT(&r->spool_chain);
off += SOF_REDIR;
r->alink = malloc(sizeof(struct alias_link *) * r->pport_cnt,
M_IPFW, M_WAITOK | M_ZERO);
switch (r->mode) {
case REDIR_ADDR:
r->alink[0] = LibAliasRedirectAddr(ptr->lib, r->laddr,
r->paddr);
break;
case REDIR_PORT:
for (i = 0 ; i < r->pport_cnt; i++) {
/* If remotePort is all ports, set it to 0. */
u_short remotePortCopy = r->rport + i;
if (r->rport_cnt == 1 && r->rport == 0)
remotePortCopy = 0;
r->alink[i] = LibAliasRedirectPort(ptr->lib,
r->laddr, htons(r->lport + i), r->raddr,
htons(remotePortCopy), r->paddr,
htons(r->pport + i), r->proto);
if (r->alink[i] == NULL) {
r->alink[0] = NULL;
break;
}
}
break;
case REDIR_PROTO:
r->alink[0] = LibAliasRedirectProto(ptr->lib ,r->laddr,
r->raddr, r->paddr, r->proto);
break;
default:
printf("unknown redirect mode: %u\n", r->mode);
break;
}
/* XXX perhaps return an error instead of panic ? */
if (r->alink[0] == NULL)
panic("LibAliasRedirect* returned NULL");
/* LSNAT handling. */
for (i = 0; i < r->spool_cnt; i++) {
ser_s = (struct cfg_spool *)&buf[off];
s = malloc(SOF_REDIR, M_IPFW, M_WAITOK | M_ZERO);
memcpy(s, ser_s, SOF_SPOOL);
LibAliasAddServer(ptr->lib, r->alink[0],
s->addr, htons(s->port));
off += SOF_SPOOL;
/* Hook spool entry. */
LIST_INSERT_HEAD(&r->spool_chain, s, _next);
}
/* And finally hook this redir entry. */
LIST_INSERT_HEAD(&ptr->redir_chain, r, _next);
}
}
static int
ipfw_nat(struct ip_fw_args *args, struct cfg_nat *t, struct mbuf *m)
{
struct mbuf *mcl;
struct ip *ip;
/* XXX - libalias duct tape */
int ldt, retval, found;
struct ip_fw_chain *chain;
char *c;
ldt = 0;
retval = 0;
mcl = m_megapullup(m, m->m_pkthdr.len);
if (mcl == NULL) {
args->m = NULL;
return (IP_FW_DENY);
}
ip = mtod(mcl, struct ip *);
/*
* XXX - Libalias checksum offload 'duct tape':
*
* locally generated packets have only pseudo-header checksum
* calculated and libalias will break it[1], so mark them for
* later fix. Moreover there are cases when libalias modifies
* tcp packet data[2], mark them for later fix too.
*
* [1] libalias was never meant to run in kernel, so it does
* not have any knowledge about checksum offloading, and
* expects a packet with a full internet checksum.
* Unfortunately, packets generated locally will have just the
* pseudo header calculated, and when libalias tries to adjust
* the checksum it will actually compute a wrong value.
*
* [2] when libalias modifies tcp's data content, full TCP
* checksum has to be recomputed: the problem is that
* libalias does not have any idea about checksum offloading.
* To work around this, we do not do checksumming in LibAlias,
* but only mark the packets in th_x2 field. If we receive a
* marked packet, we calculate correct checksum for it
* aware of offloading. Why such a terrible hack instead of
* recalculating checksum for each packet?
* Because the previous checksum was not checked!
* Recalculating checksums for EVERY packet will hide ALL
* transmission errors. Yes, marked packets still suffer from
* this problem. But, sigh, natd(8) has this problem, too.
*
* TODO: -make libalias mbuf aware (so
* it can handle delayed checksum and tso)
*/
if (mcl->m_pkthdr.rcvif == NULL &&
mcl->m_pkthdr.csum_flags & CSUM_DELAY_DATA)
ldt = 1;
c = mtod(mcl, char *);
/* Check if this is 'global' instance */
if (t == NULL) {
if (args->oif == NULL) {
/* Wrong direction, skip processing */
args->m = mcl;
return (IP_FW_NAT);
}
found = 0;
chain = &V_layer3_chain;
IPFW_RLOCK(chain);
/* Check every nat entry... */
LIST_FOREACH(t, &chain->nat, _next) {
if ((t->mode & PKT_ALIAS_SKIP_GLOBAL) != 0)
continue;
retval = LibAliasOutTry(t->lib, c,
mcl->m_len + M_TRAILINGSPACE(mcl), 0);
if (retval == PKT_ALIAS_OK) {
/* Nat instance recognises state */
found = 1;
break;
}
}
IPFW_RUNLOCK(chain);
if (found != 1) {
/* No instance found, return ignore */
args->m = mcl;
return (IP_FW_NAT);
}
} else {
if (args->oif == NULL)
retval = LibAliasIn(t->lib, c,
mcl->m_len + M_TRAILINGSPACE(mcl));
else
retval = LibAliasOut(t->lib, c,
mcl->m_len + M_TRAILINGSPACE(mcl));
}
/*
* We drop packet when:
* 1. libalias returns PKT_ALIAS_ERROR;
* 2. For incoming packets:
* a) for unresolved fragments;
* b) libalias returns PKT_ALIAS_IGNORED and
* PKT_ALIAS_DENY_INCOMING flag is set.
*/
if (retval == PKT_ALIAS_ERROR ||
(args->oif == NULL && (retval == PKT_ALIAS_UNRESOLVED_FRAGMENT ||
(retval == PKT_ALIAS_IGNORED &&
(t->mode & PKT_ALIAS_DENY_INCOMING) != 0)))) {
/* XXX - should i add some logging? */
m_free(mcl);
args->m = NULL;
return (IP_FW_DENY);
}
if (retval == PKT_ALIAS_RESPOND)
mcl->m_flags |= M_SKIP_FIREWALL;
mcl->m_pkthdr.len = mcl->m_len = ntohs(ip->ip_len);
/*
* XXX - libalias checksum offload
* 'duct tape' (see above)
*/
if ((ip->ip_off & htons(IP_OFFMASK)) == 0 &&
ip->ip_p == IPPROTO_TCP) {
struct tcphdr *th;
th = (struct tcphdr *)(ip + 1);
if (th->th_x2)
ldt = 1;
}
if (ldt) {
struct tcphdr *th;
struct udphdr *uh;
u_short cksum;
ip->ip_len = ntohs(ip->ip_len);
cksum = in_pseudo(ip->ip_src.s_addr, ip->ip_dst.s_addr,
htons(ip->ip_p + ip->ip_len - (ip->ip_hl << 2)));
switch (ip->ip_p) {
case IPPROTO_TCP:
th = (struct tcphdr *)(ip + 1);
/*
* Maybe it was set in
* libalias...
*/
th->th_x2 = 0;
th->th_sum = cksum;
mcl->m_pkthdr.csum_data =
offsetof(struct tcphdr, th_sum);
break;
case IPPROTO_UDP:
uh = (struct udphdr *)(ip + 1);
uh->uh_sum = cksum;
mcl->m_pkthdr.csum_data =
offsetof(struct udphdr, uh_sum);
break;
}
/* No hw checksum offloading: do it ourselves */
if ((mcl->m_pkthdr.csum_flags & CSUM_DELAY_DATA) == 0) {
in_delayed_cksum(mcl);
mcl->m_pkthdr.csum_flags &= ~CSUM_DELAY_DATA;
}
ip->ip_len = htons(ip->ip_len);
}
args->m = mcl;
return (IP_FW_NAT);
}
static struct cfg_nat *
lookup_nat(struct nat_list *l, int nat_id)
{
struct cfg_nat *res;
LIST_FOREACH(res, l, _next) {
if (res->id == nat_id)
break;
}
return res;
}
static int
ipfw_nat_cfg(struct sockopt *sopt)
{
struct cfg_nat *cfg, *ptr;
char *buf;
struct ip_fw_chain *chain = &V_layer3_chain;
size_t len;
int gencnt, error = 0;
len = sopt->sopt_valsize;
buf = malloc(len, M_TEMP, M_WAITOK | M_ZERO);
if ((error = sooptcopyin(sopt, buf, len, sizeof(struct cfg_nat))) != 0)
goto out;
cfg = (struct cfg_nat *)buf;
if (cfg->id < 0) {
error = EINVAL;
goto out;
}
/*
* Find/create nat rule.
*/
IPFW_WLOCK(chain);
gencnt = chain->gencnt;
ptr = lookup_nat(&chain->nat, cfg->id);
if (ptr == NULL) {
IPFW_WUNLOCK(chain);
/* New rule: allocate and init new instance. */
ptr = malloc(sizeof(struct cfg_nat), M_IPFW, M_WAITOK | M_ZERO);
ptr->lib = LibAliasInit(NULL);
LIST_INIT(&ptr->redir_chain);
} else {
/* Entry already present: temporarily unhook it. */
LIST_REMOVE(ptr, _next);
flush_nat_ptrs(chain, cfg->id);
IPFW_WUNLOCK(chain);
}
/*
* Basic nat configuration.
*/
ptr->id = cfg->id;
/*
* XXX - what if this rule doesn't nat any ip and just
* redirect?
* do we set aliasaddress to 0.0.0.0?
*/
ptr->ip = cfg->ip;
ptr->redir_cnt = cfg->redir_cnt;
ptr->mode = cfg->mode;
LibAliasSetMode(ptr->lib, cfg->mode, cfg->mode);
LibAliasSetAddress(ptr->lib, ptr->ip);
memcpy(ptr->if_name, cfg->if_name, IF_NAMESIZE);
/*
* Redir and LSNAT configuration.
*/
/* Delete old cfgs. */
del_redir_spool_cfg(ptr, &ptr->redir_chain);
/* Add new entries. */
add_redir_spool_cfg(&buf[(sizeof(struct cfg_nat))], ptr);
IPFW_WLOCK(chain);
/* Extra check to avoid race with another ipfw_nat_cfg() */
if (gencnt != chain->gencnt &&
((cfg = lookup_nat(&chain->nat, ptr->id)) != NULL))
LIST_REMOVE(cfg, _next);
LIST_INSERT_HEAD(&chain->nat, ptr, _next);
chain->gencnt++;
IPFW_WUNLOCK(chain);
out:
free(buf, M_TEMP);
return (error);
}
static int
ipfw_nat_del(struct sockopt *sopt)
{
struct cfg_nat *ptr;
struct ip_fw_chain *chain = &V_layer3_chain;
int i;
sooptcopyin(sopt, &i, sizeof i, sizeof i);
/* XXX validate i */
IPFW_WLOCK(chain);
ptr = lookup_nat(&chain->nat, i);
if (ptr == NULL) {
IPFW_WUNLOCK(chain);
return (EINVAL);
}
LIST_REMOVE(ptr, _next);
flush_nat_ptrs(chain, i);
IPFW_WUNLOCK(chain);
del_redir_spool_cfg(ptr, &ptr->redir_chain);
LibAliasUninit(ptr->lib);
free(ptr, M_IPFW);
return (0);
}
static int
ipfw_nat_get_cfg(struct sockopt *sopt)
{
struct ip_fw_chain *chain = &V_layer3_chain;
struct cfg_nat *n;
struct cfg_redir *r;
struct cfg_spool *s;
char *data;
int gencnt, nat_cnt, len, error;
nat_cnt = 0;
len = sizeof(nat_cnt);
IPFW_RLOCK(chain);
retry:
gencnt = chain->gencnt;
/* Estimate memory amount */
LIST_FOREACH(n, &chain->nat, _next) {
nat_cnt++;
len += sizeof(struct cfg_nat);
LIST_FOREACH(r, &n->redir_chain, _next) {
len += sizeof(struct cfg_redir);
LIST_FOREACH(s, &r->spool_chain, _next)
len += sizeof(struct cfg_spool);
}
}
IPFW_RUNLOCK(chain);
data = malloc(len, M_TEMP, M_WAITOK | M_ZERO);
bcopy(&nat_cnt, data, sizeof(nat_cnt));
nat_cnt = 0;
len = sizeof(nat_cnt);
IPFW_RLOCK(chain);
if (gencnt != chain->gencnt) {
free(data, M_TEMP);
goto retry;
}
/* Serialize all the data. */
LIST_FOREACH(n, &chain->nat, _next) {
bcopy(n, &data[len], sizeof(struct cfg_nat));
len += sizeof(struct cfg_nat);
LIST_FOREACH(r, &n->redir_chain, _next) {
bcopy(r, &data[len], sizeof(struct cfg_redir));
len += sizeof(struct cfg_redir);
LIST_FOREACH(s, &r->spool_chain, _next) {
bcopy(s, &data[len], sizeof(struct cfg_spool));
len += sizeof(struct cfg_spool);
}
}
}
IPFW_RUNLOCK(chain);
error = sooptcopyout(sopt, data, len);
free(data, M_TEMP);
return (error);
}
static int
ipfw_nat_get_log(struct sockopt *sopt)
{
uint8_t *data;
struct cfg_nat *ptr;
int i, size;
struct ip_fw_chain *chain;
chain = &V_layer3_chain;
IPFW_RLOCK(chain);
/* one pass to count, one to copy the data */
i = 0;
LIST_FOREACH(ptr, &chain->nat, _next) {
if (ptr->lib->logDesc == NULL)
continue;
i++;
}
size = i * (LIBALIAS_BUF_SIZE + sizeof(int));
data = malloc(size, M_IPFW, M_NOWAIT | M_ZERO);
if (data == NULL) {
IPFW_RUNLOCK(chain);
return (ENOSPC);
}
i = 0;
LIST_FOREACH(ptr, &chain->nat, _next) {
if (ptr->lib->logDesc == NULL)
continue;
bcopy(&ptr->id, &data[i], sizeof(int));
i += sizeof(int);
bcopy(ptr->lib->logDesc, &data[i], LIBALIAS_BUF_SIZE);
i += LIBALIAS_BUF_SIZE;
}
IPFW_RUNLOCK(chain);
sooptcopyout(sopt, data, size);
free(data, M_IPFW);
return(0);
}
static void
ipfw_nat_init(void)
{
IPFW_WLOCK(&V_layer3_chain);
/* init ipfw hooks */
ipfw_nat_ptr = ipfw_nat;
lookup_nat_ptr = lookup_nat;
ipfw_nat_cfg_ptr = ipfw_nat_cfg;
ipfw_nat_del_ptr = ipfw_nat_del;
ipfw_nat_get_cfg_ptr = ipfw_nat_get_cfg;
ipfw_nat_get_log_ptr = ipfw_nat_get_log;
IPFW_WUNLOCK(&V_layer3_chain);
V_ifaddr_event_tag = EVENTHANDLER_REGISTER(
ifaddr_event, ifaddr_change,
NULL, EVENTHANDLER_PRI_ANY);
}
static void
ipfw_nat_destroy(void)
{
struct cfg_nat *ptr, *ptr_temp;
struct ip_fw_chain *chain;
chain = &V_layer3_chain;
IPFW_WLOCK(chain);
LIST_FOREACH_SAFE(ptr, &chain->nat, _next, ptr_temp) {
LIST_REMOVE(ptr, _next);
del_redir_spool_cfg(ptr, &ptr->redir_chain);
LibAliasUninit(ptr->lib);
free(ptr, M_IPFW);
}
EVENTHANDLER_DEREGISTER(ifaddr_event, V_ifaddr_event_tag);
flush_nat_ptrs(chain, -1 /* flush all */);
/* deregister ipfw_nat */
ipfw_nat_ptr = NULL;
lookup_nat_ptr = NULL;
ipfw_nat_cfg_ptr = NULL;
ipfw_nat_del_ptr = NULL;
ipfw_nat_get_cfg_ptr = NULL;
ipfw_nat_get_log_ptr = NULL;
IPFW_WUNLOCK(chain);
}
static int
ipfw_nat_modevent(module_t mod, int type, void *unused)
{
int err = 0;
switch (type) {
case MOD_LOAD:
ipfw_nat_init();
break;
case MOD_UNLOAD:
ipfw_nat_destroy();
break;
default:
return EOPNOTSUPP;
break;
}
return err;
}
static moduledata_t ipfw_nat_mod = {
"ipfw_nat",
ipfw_nat_modevent,
0
};
DECLARE_MODULE(ipfw_nat, ipfw_nat_mod, SI_SUB_PROTO_IFATTACHDOMAIN, SI_ORDER_ANY);
MODULE_DEPEND(ipfw_nat, libalias, 1, 1, 1);
MODULE_DEPEND(ipfw_nat, ipfw, 2, 2, 2);
MODULE_VERSION(ipfw_nat, 1);
/* end of file */