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Move ipfw's nat code into its own kld: ipfw_nat.

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This commit is contained in:
Paolo Pisati 2008-02-29 22:27:19 +00:00
parent df09ebc0b8
commit 531c890b8a
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=176669
6 changed files with 741 additions and 553 deletions
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3
sys/conf/NOTES
View File

@ -835,8 +835,7 @@ device stf #6to4 IPv6 over IPv4 encapsulation
# crafting the ruleset.
#
# IPFIREWALL_NAT adds support for in kernel nat in ipfw, and it requires
# LIBALIAS. To build an ipfw kld with nat support enabled, add
# "CFLAGS+= -DIPFIREWALL_NAT" to your make.conf.
# LIBALIAS.
#
# IPSTEALTH enables code to support stealth forwarding (i.e., forwarding
# packets without touching the TTL). This can be useful to hide firewalls

1
sys/conf/files
View File

@ -1888,6 +1888,7 @@ netinet/ip_fastfwd.c optional inet
netinet/ip_fw2.c optional ipfirewall \
compile-with "${NORMAL_C} -I$S/contrib/pf"
netinet/ip_fw_pfil.c optional ipfirewall
netinet/ip_fw_nat.c optional ipfirewall_nat
netinet/ip_icmp.c optional inet
netinet/ip_input.c optional inet
netinet/ip_ipsec.c optional ipsec

8
sys/modules/ipfw_nat/Makefile Normal file
View File

@ -0,0 +1,8 @@
# $FreeBSD$
.PATH: ${.CURDIR}/../../netinet
KMOD= ipfw_nat
SRCS= ip_fw_nat.c
.include <bsd.kmod.mk>

32
sys/netinet/ip_fw.h
View File

@ -626,5 +626,37 @@ typedef int ip_fw_chk_t(struct ip_fw_args *args);
extern ip_fw_chk_t *ip_fw_chk_ptr;
#define IPFW_LOADED (ip_fw_chk_ptr != NULL)
#ifdef IPFW_INTERNAL
#define IPFW_TABLES_MAX 128
struct ip_fw_chain {
struct ip_fw *rules; /* list of rules */
struct ip_fw *reap; /* list of rules to reap */
LIST_HEAD(, cfg_nat) nat; /* list of nat entries */
struct radix_node_head *tables[IPFW_TABLES_MAX];
struct rwlock rwmtx;
};
#define IPFW_LOCK_INIT(_chain) \
rw_init(&(_chain)->rwmtx, "IPFW static rules")
#define IPFW_LOCK_DESTROY(_chain) rw_destroy(&(_chain)->rwmtx)
#define IPFW_WLOCK_ASSERT(_chain) rw_assert(&(_chain)->rwmtx, RA_WLOCKED)
#define IPFW_RLOCK(p) rw_rlock(&(p)->rwmtx)
#define IPFW_RUNLOCK(p) rw_runlock(&(p)->rwmtx)
#define IPFW_WLOCK(p) rw_wlock(&(p)->rwmtx)
#define IPFW_WUNLOCK(p) rw_wunlock(&(p)->rwmtx)
#define LOOKUP_NAT(l, i, p) do { \
LIST_FOREACH((p), &(l.nat), _next) { \
if ((p)->id == (i)) { \
break; \
} \
} \
} while (0)
typedef int ipfw_nat_t(struct ip_fw_args *, struct cfg_nat *, struct mbuf *);
typedef int ipfw_nat_cfg_t(struct sockopt *);
#endif
#endif /* _KERNEL */
#endif /* _IPFW2_H */

604
sys/netinet/ip_fw2.c
View File

@ -90,10 +90,6 @@ __FBSDID("$FreeBSD$");
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <netinet/sctp.h>
#ifdef IPFIREWALL_NAT
#include <netinet/libalias/alias.h>
#include <netinet/libalias/alias_local.h>
#endif
#include <netgraph/ng_ipfw.h>
#include <altq/if_altq.h>
@ -140,31 +136,19 @@ struct ip_fw_ugid {
int fw_prid;
};
#define IPFW_TABLES_MAX 128
struct ip_fw_chain {
struct ip_fw *rules; /* list of rules */
struct ip_fw *reap; /* list of rules to reap */
LIST_HEAD(, cfg_nat) nat; /* list of nat entries */
struct radix_node_head *tables[IPFW_TABLES_MAX];
struct rwlock rwmtx;
};
#define IPFW_LOCK_INIT(_chain) \
rw_init(&(_chain)->rwmtx, "IPFW static rules")
#define IPFW_LOCK_DESTROY(_chain) rw_destroy(&(_chain)->rwmtx)
#define IPFW_WLOCK_ASSERT(_chain) rw_assert(&(_chain)->rwmtx, RA_WLOCKED)
#define IPFW_RLOCK(p) rw_rlock(&(p)->rwmtx)
#define IPFW_RUNLOCK(p) rw_runlock(&(p)->rwmtx)
#define IPFW_WLOCK(p) rw_wlock(&(p)->rwmtx)
#define IPFW_WUNLOCK(p) rw_wunlock(&(p)->rwmtx)
/*
* list of rules for layer 3
*/
static struct ip_fw_chain layer3_chain;
struct ip_fw_chain layer3_chain;
MALLOC_DEFINE(M_IPFW, "IpFw/IpAcct", "IpFw/IpAcct chain's");
MALLOC_DEFINE(M_IPFW_TBL, "ipfw_tbl", "IpFw tables");
#define IPFW_NAT_LOADED (ipfw_nat_ptr != NULL)
ipfw_nat_t *ipfw_nat_ptr = NULL;
ipfw_nat_cfg_t *ipfw_nat_cfg_ptr;
ipfw_nat_cfg_t *ipfw_nat_del_ptr;
ipfw_nat_cfg_t *ipfw_nat_get_cfg_ptr;
ipfw_nat_cfg_t *ipfw_nat_get_log_ptr;
struct table_entry {
struct radix_node rn[2];
@ -307,9 +291,6 @@ static struct sysctl_oid *ip6_fw_sysctl_tree;
#endif /* INET6 */
#endif /* SYSCTL_NODE */
#ifdef IPFIREWALL_NAT
MODULE_DEPEND(ipfw, libalias, 1, 1, 1);
#endif
static int fw_deny_unknown_exthdrs = 1;
@ -2060,185 +2041,6 @@ check_uidgid(ipfw_insn_u32 *insn, int proto, struct ifnet *oif,
return match;
}
#ifdef IPFIREWALL_NAT
static eventhandler_tag ifaddr_event_tag;
static void
ifaddr_change(void *arg __unused, struct ifnet *ifp)
{
struct cfg_nat *ptr;
struct ifaddr *ifa;
IPFW_WLOCK(&layer3_chain);
/* Check every nat entry... */
LIST_FOREACH(ptr, &layer3_chain.nat, _next) {
/* ...using nic 'ifp->if_xname' as dynamic alias address. */
if (strncmp(ptr->if_name, ifp->if_xname, IF_NAMESIZE) == 0) {
mtx_lock(&ifp->if_addr_mtx);
TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
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);
}
mtx_unlock(&ifp->if_addr_mtx);
}
}
IPFW_WUNLOCK(&layer3_chain);
}
static void
flush_nat_ptrs(const int i)
{
struct ip_fw *rule;
IPFW_WLOCK_ASSERT(&layer3_chain);
for (rule = layer3_chain.rules; rule; rule = rule->next) {
ipfw_insn_nat *cmd = (ipfw_insn_nat *)ACTION_PTR(rule);
if (cmd->o.opcode != O_NAT)
continue;
if (cmd->nat != NULL && cmd->nat->id == i)
cmd->nat = NULL;
}
}
static struct cfg_nat *
lookup_nat(const int i)
{
struct cfg_nat *ptr;
LIST_FOREACH(ptr, &layer3_chain.nat, _next)
if (ptr->id == i)
return(ptr);
return (NULL);
}
#define HOOK_NAT(b, p) do { \
IPFW_WLOCK_ASSERT(&layer3_chain); \
LIST_INSERT_HEAD(b, p, _next); \
} while (0)
#define UNHOOK_NAT(p) do { \
IPFW_WLOCK_ASSERT(&layer3_chain); \
LIST_REMOVE(p, _next); \
} while (0)
#define HOOK_REDIR(b, p) do { \
LIST_INSERT_HEAD(b, p, _next); \
} while (0)
#define HOOK_SPOOL(b, p) do { \
LIST_INSERT_HEAD(b, p, _next); \
} while (0)
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 int
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;
char *panic_err;
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;
}
if (r->alink[0] == NULL) {
panic_err = "LibAliasRedirect* returned NULL";
goto bad;
} else /* 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. */
HOOK_SPOOL(&r->spool_chain, s);
}
/* And finally hook this redir entry. */
HOOK_REDIR(&ptr->redir_chain, r);
}
return (1);
bad:
/* something really bad happened: panic! */
panic("%s\n", panic_err);
}
#endif
/*
* The main check routine for the firewall.
*
@ -3481,180 +3283,28 @@ do { \
IP_FW_NETGRAPH : IP_FW_NGTEE;
goto done;
#ifdef IPFIREWALL_NAT
case O_NAT: {
struct cfg_nat *t;
struct mbuf *mcl;
/* XXX - libalias duct tape */
int ldt, nat_id;
char *c;
ldt = 0;
args->rule = f; /* Report matching rule. */
retval = 0;
t = ((ipfw_insn_nat *)cmd)->nat;
if (t == NULL) {
nat_id = (cmd->arg1 == IP_FW_TABLEARG) ?
tablearg : cmd->arg1;
t = lookup_nat(nat_id);
struct cfg_nat *t;
int nat_id;
if (IPFW_NAT_LOADED) {
args->rule = f; /* Report matching rule. */
t = ((ipfw_insn_nat *)cmd)->nat;
if (t == NULL) {
retval = IP_FW_DENY;
goto done;
} else
((ipfw_insn_nat *)cmd)->nat =
t;
}
if ((mcl = m_megapullup(m, m->m_pkthdr.len)) ==
NULL)
goto badnat;
ip = mtod(mcl, struct ip *);
if (args->eh == NULL) {
ip->ip_len = htons(ip->ip_len);
ip->ip_off = htons(ip->ip_off);
}
/*
* XXX - Libalias checksum offload 'duct tape':
*
* locally generated packets have only
* pseudo-header checksum calculated
* and libalias will screw it[1], so
* mark them for later fix. Moreover
* there are cases when libalias
* modify tcp packet data[2], mark it
* for later fix too.
*
* [1] libalias was never meant to run
* in kernel, so it doesn't have any
* knowledge about checksum
* offloading, and it 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 screw it.
*
* [2] when libalias modify tcp's data
* content, full TCP checksum has to
* be recomputed: the problem is that
* libalias doesn't have any idea
* about checksum offloading To
* workaround 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 *);
if (oif == NULL)
retval = LibAliasIn(t->lib, c,
MCLBYTES);
else
retval = LibAliasOut(t->lib, c,
MCLBYTES);
if (retval != PKT_ALIAS_OK) {
/* XXX - should i add some logging? */
m_free(mcl);
badnat:
args->m = NULL;
nat_id = (cmd->arg1 == IP_FW_TABLEARG) ?
tablearg : cmd->arg1;
LOOKUP_NAT(layer3_chain, nat_id, t);
if (t == NULL) {
retval = IP_FW_DENY;
goto done;
} else
((ipfw_insn_nat *)cmd)->nat = t;
}
retval = ipfw_nat_ptr(args, t, m);
} else
retval = IP_FW_DENY;
goto done;
}
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
* by ourself.
*/
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);
}
if (args->eh == NULL) {
ip->ip_len = ntohs(ip->ip_len);
ip->ip_off = ntohs(ip->ip_off);
}
args->m = mcl;
retval = IP_FW_NAT;
goto done;
}
#endif
default:
panic("-- unknown opcode %d\n", cmd->opcode);
@ -4262,13 +3912,11 @@ check_ipfw_struct(struct ip_fw *rule, int size)
else
goto check_size;
case O_NAT:
#ifdef IPFIREWALL_NAT
if (!IPFW_NAT_LOADED)
return EINVAL;
if (cmdlen != F_INSN_SIZE(ipfw_insn_nat))
goto bad_size;
goto check_action;
#else
return EINVAL;
#endif
case O_FORWARD_MAC: /* XXX not implemented yet */
case O_CHECK_STATE:
case O_COUNT:
@ -4661,186 +4309,50 @@ ipfw_ctl(struct sockopt *sopt)
}
break;
#ifdef IPFIREWALL_NAT
case IP_FW_NAT_CFG:
{
struct cfg_nat *ptr, *ser_n;
char *buf;
buf = malloc(NAT_BUF_LEN, M_IPFW, M_WAITOK | M_ZERO);
error = sooptcopyin(sopt, buf, NAT_BUF_LEN,
sizeof(struct cfg_nat));
ser_n = (struct cfg_nat *)buf;
/*
* Find/create nat rule.
*/
IPFW_WLOCK(&layer3_chain);
ptr = lookup_nat(ser_n->id);
if (ptr == NULL) {
/* New rule: allocate and init new instance. */
ptr = malloc(sizeof(struct cfg_nat),
M_IPFW, M_NOWAIT | M_ZERO);
if (ptr == NULL) {
IPFW_WUNLOCK(&layer3_chain);
free(buf, M_IPFW);
return (ENOSPC);
}
ptr->lib = LibAliasInit(NULL);
if (ptr->lib == NULL) {
IPFW_WUNLOCK(&layer3_chain);
free(ptr, M_IPFW);
free(buf, M_IPFW);
return (EINVAL);
}
LIST_INIT(&ptr->redir_chain);
} else {
/* Entry already present: temporarly unhook it. */
UNHOOK_NAT(ptr);
flush_nat_ptrs(ser_n->id);
if (IPFW_NAT_LOADED)
error = ipfw_nat_cfg_ptr(sopt);
else {
printf("IP_FW_NAT_CFG: ipfw_nat not present, please load it.\n");
error = EINVAL;
}
IPFW_WUNLOCK(&layer3_chain);
/*
* Basic nat configuration.
*/
ptr->id = ser_n->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 = ser_n->ip;
ptr->redir_cnt = ser_n->redir_cnt;
ptr->mode = ser_n->mode;
LibAliasSetMode(ptr->lib, ser_n->mode, ser_n->mode);
LibAliasSetAddress(ptr->lib, ptr->ip);
memcpy(ptr->if_name, ser_n->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);
free(buf, M_IPFW);
IPFW_WLOCK(&layer3_chain);
HOOK_NAT(&layer3_chain.nat, ptr);
IPFW_WUNLOCK(&layer3_chain);
}
break;
case IP_FW_NAT_DEL:
{
struct cfg_nat *ptr;
int i;
error = sooptcopyin(sopt, &i, sizeof i, sizeof i);
IPFW_WLOCK(&layer3_chain);
ptr = lookup_nat(i);
if (ptr == NULL) {
if (IPFW_NAT_LOADED)
error = ipfw_nat_del_ptr(sopt);
else {
printf("IP_FW_NAT_DEL: ipfw_nat not present, please load it.\n");
printf("ipfw_nat not loaded: %d\n", sopt->sopt_name);
error = EINVAL;
IPFW_WUNLOCK(&layer3_chain);
break;
}
UNHOOK_NAT(ptr);
flush_nat_ptrs(i);
IPFW_WUNLOCK(&layer3_chain);
del_redir_spool_cfg(ptr, &ptr->redir_chain);
LibAliasUninit(ptr->lib);
free(ptr, M_IPFW);
}
break;
case IP_FW_NAT_GET_CONFIG:
{
uint8_t *data;
struct cfg_nat *n;
struct cfg_redir *r;
struct cfg_spool *s;
int nat_cnt, off;
nat_cnt = 0;
off = sizeof(nat_cnt);
data = malloc(NAT_BUF_LEN, M_IPFW, M_WAITOK | M_ZERO);
IPFW_RLOCK(&layer3_chain);
/* Serialize all the data. */
LIST_FOREACH(n, &layer3_chain.nat, _next) {
nat_cnt++;
if (off + SOF_NAT < NAT_BUF_LEN) {
bcopy(n, &data[off], SOF_NAT);
off += SOF_NAT;
LIST_FOREACH(r, &n->redir_chain, _next) {
if (off + SOF_REDIR < NAT_BUF_LEN) {
bcopy(r, &data[off],
SOF_REDIR);
off += SOF_REDIR;
LIST_FOREACH(s, &r->spool_chain,
_next) {
if (off + SOF_SPOOL <
NAT_BUF_LEN) {
bcopy(s,
&data[off],
SOF_SPOOL);
off +=
SOF_SPOOL;
} else
goto nospace;
}
} else
goto nospace;
}
} else
goto nospace;
if (IPFW_NAT_LOADED)
error = ipfw_nat_get_cfg_ptr(sopt);
else {
printf("IP_FW_NAT_GET_CFG: ipfw_nat not present, please load it.\n");
error = EINVAL;
}
bcopy(&nat_cnt, data, sizeof(nat_cnt));
IPFW_RUNLOCK(&layer3_chain);
error = sooptcopyout(sopt, data, NAT_BUF_LEN);
free(data, M_IPFW);
break;
nospace:
IPFW_RUNLOCK(&layer3_chain);
printf("serialized data buffer not big enough:"
"please increase NAT_BUF_LEN\n");
free(data, M_IPFW);
}
break;
case IP_FW_NAT_GET_LOG:
{
uint8_t *data;
struct cfg_nat *ptr;
int i, size, cnt, sof;
data = NULL;
sof = LIBALIAS_BUF_SIZE;
cnt = 0;
IPFW_RLOCK(&layer3_chain);
size = i = 0;
LIST_FOREACH(ptr, &layer3_chain.nat, _next) {
if (ptr->lib->logDesc == NULL)
continue;
cnt++;
size = cnt * (sof + sizeof(int));
data = realloc(data, size, M_IPFW, M_NOWAIT | M_ZERO);
if (data == NULL) {
IPFW_RUNLOCK(&layer3_chain);
return (ENOSPC);
}
bcopy(&ptr->id, &data[i], sizeof(int));
i += sizeof(int);
bcopy(ptr->lib->logDesc, &data[i], sof);
i += sof;
if (IPFW_NAT_LOADED)
error = ipfw_nat_get_log_ptr(sopt);
else {
printf("IP_FW_NAT_GET_LOG: ipfw_nat not present, please load it.\n");
error = EINVAL;
}
IPFW_RUNLOCK(&layer3_chain);
error = sooptcopyout(sopt, data, size);
free(data, M_IPFW);
}
break;
#endif
default:
printf("ipfw: ipfw_ctl invalid option %d\n", sopt->sopt_name);
@ -4975,7 +4487,7 @@ ipfw_init(void)
#ifdef INET6
"(+ipv6) "
#endif
"initialized, divert %s, "
"initialized, divert %s, nat %s, "
"rule-based forwarding "
#ifdef IPFIREWALL_FORWARD
"enabled, "
@ -4988,6 +4500,12 @@ ipfw_init(void)
#else
"loadable",
#endif
#ifdef IPFIREWALL_NAT
"enabled",
#else
"loadable",
#endif
default_rule.cmd[0].opcode == O_ACCEPT ? "accept" : "deny");
#ifdef IPFIREWALL_VERBOSE
@ -5014,11 +4532,7 @@ ipfw_init(void)
ip_fw_ctl_ptr = ipfw_ctl;
ip_fw_chk_ptr = ipfw_chk;
callout_reset(&ipfw_timeout, hz, ipfw_tick, NULL);
#ifdef IPFIREWALL_NAT
LIST_INIT(&layer3_chain.nat);
ifaddr_event_tag = EVENTHANDLER_REGISTER(ifaddr_event, ifaddr_change,
NULL, EVENTHANDLER_PRI_ANY);
#endif
return (0);
}
@ -5026,24 +4540,12 @@ void
ipfw_destroy(void)
{
struct ip_fw *reap;
#ifdef IPFIREWALL_NAT
struct cfg_nat *ptr, *ptr_temp;
#endif
ip_fw_chk_ptr = NULL;
ip_fw_ctl_ptr = NULL;
callout_drain(&ipfw_timeout);
IPFW_WLOCK(&layer3_chain);
flush_tables(&layer3_chain);
#ifdef IPFIREWALL_NAT
LIST_FOREACH_SAFE(ptr, &layer3_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, ifaddr_event_tag);
#endif
layer3_chain.reap = NULL;
free_chain(&layer3_chain, 1 /* kill default rule */);
reap = layer3_chain.reap, layer3_chain.reap = NULL;

646
sys/netinet/ip_fw_nat.c Normal file
View File

@ -0,0 +1,646 @@
/*-
* 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("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/condvar.h>
#include <sys/eventhandler.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/jail.h>
#include <sys/module.h>
#include <sys/priv.h>
#include <sys/proc.h>
#include <sys/rwlock.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/ucred.h>
#include <netinet/libalias/alias.h>
#include <netinet/libalias/alias_local.h>
#define IPFW_INTERNAL /* Access to protected data structures in ip_fw.h. */
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/ip_icmp.h>
#include <netinet/ip_fw.h>
#include <netinet/tcp.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
#include <netinet/tcpip.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <machine/in_cksum.h> /* XXX for in_cksum */
MALLOC_DECLARE(M_IPFW);
extern struct ip_fw_chain layer3_chain;
static eventhandler_tag ifaddr_event_tag;
extern ipfw_nat_t *ipfw_nat_ptr;
extern ipfw_nat_cfg_t *ipfw_nat_cfg_ptr;
extern ipfw_nat_cfg_t *ipfw_nat_del_ptr;
extern ipfw_nat_cfg_t *ipfw_nat_get_cfg_ptr;
extern ipfw_nat_cfg_t *ipfw_nat_get_log_ptr;
static void
ifaddr_change(void *arg __unused, struct ifnet *ifp)
{
struct cfg_nat *ptr;
struct ifaddr *ifa;
IPFW_WLOCK(&layer3_chain);
/* Check every nat entry... */
LIST_FOREACH(ptr, &layer3_chain.nat, _next) {
/* ...using nic 'ifp->if_xname' as dynamic alias address. */
if (strncmp(ptr->if_name, ifp->if_xname, IF_NAMESIZE) == 0) {
mtx_lock(&ifp->if_addr_mtx);
TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
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);
}
mtx_unlock(&ifp->if_addr_mtx);
}
}
IPFW_WUNLOCK(&layer3_chain);
}
static void
flush_nat_ptrs(const int i)
{
struct ip_fw *rule;
IPFW_WLOCK_ASSERT(&layer3_chain);
for (rule = layer3_chain.rules; rule; rule = rule->next) {
ipfw_insn_nat *cmd = (ipfw_insn_nat *)ACTION_PTR(rule);
if (cmd->o.opcode != O_NAT)
continue;
if (cmd->nat != NULL && cmd->nat->id == i)
cmd->nat = NULL;
}
}
#define HOOK_NAT(b, p) do { \
IPFW_WLOCK_ASSERT(&layer3_chain); \
LIST_INSERT_HEAD(b, p, _next); \
} while (0)
#define UNHOOK_NAT(p) do { \
IPFW_WLOCK_ASSERT(&layer3_chain); \
LIST_REMOVE(p, _next); \
} while (0)
#define HOOK_REDIR(b, p) do { \
LIST_INSERT_HEAD(b, p, _next); \
} while (0)
#define HOOK_SPOOL(b, p) do { \
LIST_INSERT_HEAD(b, p, _next); \
} while (0)
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 int
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;
char *panic_err;
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;
}
if (r->alink[0] == NULL) {
panic_err = "LibAliasRedirect* returned NULL";
goto bad;
} else /* 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. */
HOOK_SPOOL(&r->spool_chain, s);
}
/* And finally hook this redir entry. */
HOOK_REDIR(&ptr->redir_chain, r);
}
return (1);
bad:
/* something really bad happened: panic! */
panic("%s\n", panic_err);
}
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;
char *c;
ldt = 0;
retval = 0;
if ((mcl = m_megapullup(m, m->m_pkthdr.len)) ==
NULL)
goto badnat;
ip = mtod(mcl, struct ip *);
if (args->eh == NULL) {
ip->ip_len = htons(ip->ip_len);
ip->ip_off = htons(ip->ip_off);
}
/*
* XXX - Libalias checksum offload 'duct tape':
*
* locally generated packets have only
* pseudo-header checksum calculated
* and libalias will screw it[1], so
* mark them for later fix. Moreover
* there are cases when libalias
* modify tcp packet data[2], mark it
* for later fix too.
*
* [1] libalias was never meant to run
* in kernel, so it doesn't have any
* knowledge about checksum
* offloading, and it 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 screw it.
*
* [2] when libalias modify tcp's data
* content, full TCP checksum has to
* be recomputed: the problem is that
* libalias doesn't have any idea
* about checksum offloading To
* workaround 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 *);
if (args->oif == NULL)
retval = LibAliasIn(t->lib, c,
MCLBYTES);
else
retval = LibAliasOut(t->lib, c,
MCLBYTES);
if (retval != PKT_ALIAS_OK) {
/* XXX - should i add some logging? */
m_free(mcl);
badnat:
args->m = NULL;
return (IP_FW_DENY);
}
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
* by ourself.
*/
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);
}
if (args->eh == NULL) {
ip->ip_len = ntohs(ip->ip_len);
ip->ip_off = ntohs(ip->ip_off);
}
args->m = mcl;
return (IP_FW_NAT);
}
static int
ipfw_nat_cfg(struct sockopt *sopt)
{
struct cfg_nat *ptr, *ser_n;
char *buf;
buf = malloc(NAT_BUF_LEN, M_IPFW, M_WAITOK | M_ZERO);
sooptcopyin(sopt, buf, NAT_BUF_LEN,
sizeof(struct cfg_nat));
ser_n = (struct cfg_nat *)buf;
/*
* Find/create nat rule.
*/
IPFW_WLOCK(&layer3_chain);
LOOKUP_NAT(layer3_chain, ser_n->id, ptr);
if (ptr == NULL) {
/* New rule: allocate and init new instance. */
ptr = malloc(sizeof(struct cfg_nat),
M_IPFW, M_NOWAIT | M_ZERO);
if (ptr == NULL) {
IPFW_WUNLOCK(&layer3_chain);
free(buf, M_IPFW);
return (ENOSPC);
}
ptr->lib = LibAliasInit(NULL);
if (ptr->lib == NULL) {
IPFW_WUNLOCK(&layer3_chain);
free(ptr, M_IPFW);
free(buf, M_IPFW);
return (EINVAL);
}
LIST_INIT(&ptr->redir_chain);
} else {
/* Entry already present: temporarly unhook it. */
UNHOOK_NAT(ptr);
flush_nat_ptrs(ser_n->id);
}
IPFW_WUNLOCK(&layer3_chain);
/*
* Basic nat configuration.
*/
ptr->id = ser_n->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 = ser_n->ip;
ptr->redir_cnt = ser_n->redir_cnt;
ptr->mode = ser_n->mode;
LibAliasSetMode(ptr->lib, ser_n->mode, ser_n->mode);
LibAliasSetAddress(ptr->lib, ptr->ip);
memcpy(ptr->if_name, ser_n->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);
free(buf, M_IPFW);
IPFW_WLOCK(&layer3_chain);
HOOK_NAT(&layer3_chain.nat, ptr);
IPFW_WUNLOCK(&layer3_chain);
return (0);
}
static int
ipfw_nat_del(struct sockopt *sopt)
{
struct cfg_nat *ptr;
int i;
sooptcopyin(sopt, &i, sizeof i, sizeof i);
IPFW_WLOCK(&layer3_chain);
LOOKUP_NAT(layer3_chain, i, ptr);
if (ptr == NULL) {
IPFW_WUNLOCK(&layer3_chain);
return (EINVAL);
}
UNHOOK_NAT(ptr);
flush_nat_ptrs(i);
IPFW_WUNLOCK(&layer3_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)
{
uint8_t *data;
struct cfg_nat *n;
struct cfg_redir *r;
struct cfg_spool *s;
int nat_cnt, off;
nat_cnt = 0;
off = sizeof(nat_cnt);
data = malloc(NAT_BUF_LEN, M_IPFW, M_WAITOK | M_ZERO);
IPFW_RLOCK(&layer3_chain);
/* Serialize all the data. */
LIST_FOREACH(n, &layer3_chain.nat, _next) {
nat_cnt++;
if (off + SOF_NAT < NAT_BUF_LEN) {
bcopy(n, &data[off], SOF_NAT);
off += SOF_NAT;
LIST_FOREACH(r, &n->redir_chain, _next) {
if (off + SOF_REDIR < NAT_BUF_LEN) {
bcopy(r, &data[off],
SOF_REDIR);
off += SOF_REDIR;
LIST_FOREACH(s, &r->spool_chain,
_next) {
if (off + SOF_SPOOL <
NAT_BUF_LEN) {
bcopy(s, &data[off],
SOF_SPOOL);
off += SOF_SPOOL;
} else
goto nospace;
}
} else
goto nospace;
}
} else
goto nospace;
}
bcopy(&nat_cnt, data, sizeof(nat_cnt));
IPFW_RUNLOCK(&layer3_chain);
sooptcopyout(sopt, data, NAT_BUF_LEN);
free(data, M_IPFW);
return (0);
nospace:
IPFW_RUNLOCK(&layer3_chain);
printf("serialized data buffer not big enough:"
"please increase NAT_BUF_LEN\n");
free(data, M_IPFW);
return (ENOSPC);
}
static int
ipfw_nat_get_log(struct sockopt *sopt)
{
uint8_t *data;
struct cfg_nat *ptr;
int i, size, cnt, sof;
data = NULL;
sof = LIBALIAS_BUF_SIZE;
cnt = 0;
IPFW_RLOCK(&layer3_chain);
size = i = 0;
LIST_FOREACH(ptr, &layer3_chain.nat, _next) {
if (ptr->lib->logDesc == NULL)
continue;
cnt++;
size = cnt * (sof + sizeof(int));
data = realloc(data, size, M_IPFW, M_NOWAIT | M_ZERO);
if (data == NULL) {
IPFW_RUNLOCK(&layer3_chain);
return (ENOSPC);
}
bcopy(&ptr->id, &data[i], sizeof(int));
i += sizeof(int);
bcopy(ptr->lib->logDesc, &data[i], sof);
i += sof;
}
IPFW_RUNLOCK(&layer3_chain);
sooptcopyout(sopt, data, size);
free(data, M_IPFW);
return(0);
}
static void
ipfw_nat_init(void)
{
IPFW_WLOCK(&layer3_chain);
/* init ipfw hooks */
ipfw_nat_ptr = ipfw_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(&layer3_chain);
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;
IPFW_WLOCK(&layer3_chain);
LIST_FOREACH_SAFE(ptr, &layer3_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, ifaddr_event_tag);
/* deregister ipfw_nat */
ipfw_nat_ptr = NULL;
IPFW_WUNLOCK(&layer3_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);