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-rw-r--r--net/netfilter/nf_nat_proto.c744
1 files changed, 712 insertions, 32 deletions
diff --git a/net/netfilter/nf_nat_proto.c b/net/netfilter/nf_nat_proto.c
index f83bf9d8c9f5..62743da3004f 100644
--- a/net/netfilter/nf_nat_proto.c
+++ b/net/netfilter/nf_nat_proto.c
@@ -20,13 +20,26 @@
#include <linux/netfilter.h>
#include <net/netfilter/nf_nat.h>
-#include <net/netfilter/nf_nat_core.h>
-#include <net/netfilter/nf_nat_l3proto.h>
-#include <net/netfilter/nf_nat_l4proto.h>
+
+#include <linux/ipv6.h>
+#include <linux/netfilter_ipv6.h>
+#include <net/checksum.h>
+#include <net/ip6_checksum.h>
+#include <net/ip6_route.h>
+#include <net/xfrm.h>
+#include <net/ipv6.h>
+
+#include <net/netfilter/nf_conntrack_core.h>
+#include <net/netfilter/nf_conntrack.h>
+#include <linux/netfilter/nfnetlink_conntrack.h>
+
+static void nf_csum_update(struct sk_buff *skb,
+ unsigned int iphdroff, __sum16 *check,
+ const struct nf_conntrack_tuple *t,
+ enum nf_nat_manip_type maniptype);
static void
__udp_manip_pkt(struct sk_buff *skb,
- const struct nf_nat_l3proto *l3proto,
unsigned int iphdroff, struct udphdr *hdr,
const struct nf_conntrack_tuple *tuple,
enum nf_nat_manip_type maniptype, bool do_csum)
@@ -43,8 +56,7 @@ __udp_manip_pkt(struct sk_buff *skb,
portptr = &hdr->dest;
}
if (do_csum) {
- l3proto->csum_update(skb, iphdroff, &hdr->check,
- tuple, maniptype);
+ nf_csum_update(skb, iphdroff, &hdr->check, tuple, maniptype);
inet_proto_csum_replace2(&hdr->check, skb, *portptr, newport,
false);
if (!hdr->check)
@@ -54,7 +66,6 @@ __udp_manip_pkt(struct sk_buff *skb,
}
static bool udp_manip_pkt(struct sk_buff *skb,
- const struct nf_nat_l3proto *l3proto,
unsigned int iphdroff, unsigned int hdroff,
const struct nf_conntrack_tuple *tuple,
enum nf_nat_manip_type maniptype)
@@ -68,12 +79,11 @@ static bool udp_manip_pkt(struct sk_buff *skb,
hdr = (struct udphdr *)(skb->data + hdroff);
do_csum = hdr->check || skb->ip_summed == CHECKSUM_PARTIAL;
- __udp_manip_pkt(skb, l3proto, iphdroff, hdr, tuple, maniptype, do_csum);
+ __udp_manip_pkt(skb, iphdroff, hdr, tuple, maniptype, do_csum);
return true;
}
static bool udplite_manip_pkt(struct sk_buff *skb,
- const struct nf_nat_l3proto *l3proto,
unsigned int iphdroff, unsigned int hdroff,
const struct nf_conntrack_tuple *tuple,
enum nf_nat_manip_type maniptype)
@@ -85,14 +95,13 @@ static bool udplite_manip_pkt(struct sk_buff *skb,
return false;
hdr = (struct udphdr *)(skb->data + hdroff);
- __udp_manip_pkt(skb, l3proto, iphdroff, hdr, tuple, maniptype, true);
+ __udp_manip_pkt(skb, iphdroff, hdr, tuple, maniptype, true);
#endif
return true;
}
static bool
sctp_manip_pkt(struct sk_buff *skb,
- const struct nf_nat_l3proto *l3proto,
unsigned int iphdroff, unsigned int hdroff,
const struct nf_conntrack_tuple *tuple,
enum nf_nat_manip_type maniptype)
@@ -135,7 +144,6 @@ sctp_manip_pkt(struct sk_buff *skb,
static bool
tcp_manip_pkt(struct sk_buff *skb,
- const struct nf_nat_l3proto *l3proto,
unsigned int iphdroff, unsigned int hdroff,
const struct nf_conntrack_tuple *tuple,
enum nf_nat_manip_type maniptype)
@@ -171,14 +179,13 @@ tcp_manip_pkt(struct sk_buff *skb,
if (hdrsize < sizeof(*hdr))
return true;
- l3proto->csum_update(skb, iphdroff, &hdr->check, tuple, maniptype);
+ nf_csum_update(skb, iphdroff, &hdr->check, tuple, maniptype);
inet_proto_csum_replace2(&hdr->check, skb, oldport, newport, false);
return true;
}
static bool
dccp_manip_pkt(struct sk_buff *skb,
- const struct nf_nat_l3proto *l3proto,
unsigned int iphdroff, unsigned int hdroff,
const struct nf_conntrack_tuple *tuple,
enum nf_nat_manip_type maniptype)
@@ -210,8 +217,7 @@ dccp_manip_pkt(struct sk_buff *skb,
if (hdrsize < sizeof(*hdr))
return true;
- l3proto->csum_update(skb, iphdroff, &hdr->dccph_checksum,
- tuple, maniptype);
+ nf_csum_update(skb, iphdroff, &hdr->dccph_checksum, tuple, maniptype);
inet_proto_csum_replace2(&hdr->dccph_checksum, skb, oldport, newport,
false);
#endif
@@ -220,7 +226,6 @@ dccp_manip_pkt(struct sk_buff *skb,
static bool
icmp_manip_pkt(struct sk_buff *skb,
- const struct nf_nat_l3proto *l3proto,
unsigned int iphdroff, unsigned int hdroff,
const struct nf_conntrack_tuple *tuple,
enum nf_nat_manip_type maniptype)
@@ -239,7 +244,6 @@ icmp_manip_pkt(struct sk_buff *skb,
static bool
icmpv6_manip_pkt(struct sk_buff *skb,
- const struct nf_nat_l3proto *l3proto,
unsigned int iphdroff, unsigned int hdroff,
const struct nf_conntrack_tuple *tuple,
enum nf_nat_manip_type maniptype)
@@ -250,8 +254,7 @@ icmpv6_manip_pkt(struct sk_buff *skb,
return false;
hdr = (struct icmp6hdr *)(skb->data + hdroff);
- l3proto->csum_update(skb, iphdroff, &hdr->icmp6_cksum,
- tuple, maniptype);
+ nf_csum_update(skb, iphdroff, &hdr->icmp6_cksum, tuple, maniptype);
if (hdr->icmp6_type == ICMPV6_ECHO_REQUEST ||
hdr->icmp6_type == ICMPV6_ECHO_REPLY) {
inet_proto_csum_replace2(&hdr->icmp6_cksum, skb,
@@ -265,7 +268,6 @@ icmpv6_manip_pkt(struct sk_buff *skb,
/* manipulate a GRE packet according to maniptype */
static bool
gre_manip_pkt(struct sk_buff *skb,
- const struct nf_nat_l3proto *l3proto,
unsigned int iphdroff, unsigned int hdroff,
const struct nf_conntrack_tuple *tuple,
enum nf_nat_manip_type maniptype)
@@ -304,40 +306,718 @@ gre_manip_pkt(struct sk_buff *skb,
return true;
}
-bool nf_nat_l4proto_manip_pkt(struct sk_buff *skb,
- const struct nf_nat_l3proto *l3proto,
+static bool l4proto_manip_pkt(struct sk_buff *skb,
unsigned int iphdroff, unsigned int hdroff,
const struct nf_conntrack_tuple *tuple,
enum nf_nat_manip_type maniptype)
{
switch (tuple->dst.protonum) {
case IPPROTO_TCP:
- return tcp_manip_pkt(skb, l3proto, iphdroff, hdroff,
+ return tcp_manip_pkt(skb, iphdroff, hdroff,
tuple, maniptype);
case IPPROTO_UDP:
- return udp_manip_pkt(skb, l3proto, iphdroff, hdroff,
+ return udp_manip_pkt(skb, iphdroff, hdroff,
tuple, maniptype);
case IPPROTO_UDPLITE:
- return udplite_manip_pkt(skb, l3proto, iphdroff, hdroff,
+ return udplite_manip_pkt(skb, iphdroff, hdroff,
tuple, maniptype);
case IPPROTO_SCTP:
- return sctp_manip_pkt(skb, l3proto, iphdroff, hdroff,
+ return sctp_manip_pkt(skb, iphdroff, hdroff,
tuple, maniptype);
case IPPROTO_ICMP:
- return icmp_manip_pkt(skb, l3proto, iphdroff, hdroff,
+ return icmp_manip_pkt(skb, iphdroff, hdroff,
tuple, maniptype);
case IPPROTO_ICMPV6:
- return icmpv6_manip_pkt(skb, l3proto, iphdroff, hdroff,
+ return icmpv6_manip_pkt(skb, iphdroff, hdroff,
tuple, maniptype);
case IPPROTO_DCCP:
- return dccp_manip_pkt(skb, l3proto, iphdroff, hdroff,
+ return dccp_manip_pkt(skb, iphdroff, hdroff,
tuple, maniptype);
case IPPROTO_GRE:
- return gre_manip_pkt(skb, l3proto, iphdroff, hdroff,
+ return gre_manip_pkt(skb, iphdroff, hdroff,
tuple, maniptype);
}
/* If we don't know protocol -- no error, pass it unmodified. */
return true;
}
-EXPORT_SYMBOL_GPL(nf_nat_l4proto_manip_pkt);
+
+static bool nf_nat_ipv4_manip_pkt(struct sk_buff *skb,
+ unsigned int iphdroff,
+ const struct nf_conntrack_tuple *target,
+ enum nf_nat_manip_type maniptype)
+{
+ struct iphdr *iph;
+ unsigned int hdroff;
+
+ if (!skb_make_writable(skb, iphdroff + sizeof(*iph)))
+ return false;
+
+ iph = (void *)skb->data + iphdroff;
+ hdroff = iphdroff + iph->ihl * 4;
+
+ if (!l4proto_manip_pkt(skb, iphdroff, hdroff, target, maniptype))
+ return false;
+ iph = (void *)skb->data + iphdroff;
+
+ if (maniptype == NF_NAT_MANIP_SRC) {
+ csum_replace4(&iph->check, iph->saddr, target->src.u3.ip);
+ iph->saddr = target->src.u3.ip;
+ } else {
+ csum_replace4(&iph->check, iph->daddr, target->dst.u3.ip);
+ iph->daddr = target->dst.u3.ip;
+ }
+ return true;
+}
+
+static bool nf_nat_ipv6_manip_pkt(struct sk_buff *skb,
+ unsigned int iphdroff,
+ const struct nf_conntrack_tuple *target,
+ enum nf_nat_manip_type maniptype)
+{
+#if IS_ENABLED(CONFIG_IPV6)
+ struct ipv6hdr *ipv6h;
+ __be16 frag_off;
+ int hdroff;
+ u8 nexthdr;
+
+ if (!skb_make_writable(skb, iphdroff + sizeof(*ipv6h)))
+ return false;
+
+ ipv6h = (void *)skb->data + iphdroff;
+ nexthdr = ipv6h->nexthdr;
+ hdroff = ipv6_skip_exthdr(skb, iphdroff + sizeof(*ipv6h),
+ &nexthdr, &frag_off);
+ if (hdroff < 0)
+ goto manip_addr;
+
+ if ((frag_off & htons(~0x7)) == 0 &&
+ !l4proto_manip_pkt(skb, iphdroff, hdroff, target, maniptype))
+ return false;
+
+ /* must reload, offset might have changed */
+ ipv6h = (void *)skb->data + iphdroff;
+
+manip_addr:
+ if (maniptype == NF_NAT_MANIP_SRC)
+ ipv6h->saddr = target->src.u3.in6;
+ else
+ ipv6h->daddr = target->dst.u3.in6;
+
+#endif
+ return true;
+}
+
+unsigned int nf_nat_manip_pkt(struct sk_buff *skb, struct nf_conn *ct,
+ enum nf_nat_manip_type mtype,
+ enum ip_conntrack_dir dir)
+{
+ struct nf_conntrack_tuple target;
+
+ /* We are aiming to look like inverse of other direction. */
+ nf_ct_invert_tuple(&target, &ct->tuplehash[!dir].tuple);
+
+ switch (target.src.l3num) {
+ case NFPROTO_IPV6:
+ if (nf_nat_ipv6_manip_pkt(skb, 0, &target, mtype))
+ return NF_ACCEPT;
+ break;
+ case NFPROTO_IPV4:
+ if (nf_nat_ipv4_manip_pkt(skb, 0, &target, mtype))
+ return NF_ACCEPT;
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ break;
+ }
+
+ return NF_DROP;
+}
+
+static void nf_nat_ipv4_csum_update(struct sk_buff *skb,
+ unsigned int iphdroff, __sum16 *check,
+ const struct nf_conntrack_tuple *t,
+ enum nf_nat_manip_type maniptype)
+{
+ struct iphdr *iph = (struct iphdr *)(skb->data + iphdroff);
+ __be32 oldip, newip;
+
+ if (maniptype == NF_NAT_MANIP_SRC) {
+ oldip = iph->saddr;
+ newip = t->src.u3.ip;
+ } else {
+ oldip = iph->daddr;
+ newip = t->dst.u3.ip;
+ }
+ inet_proto_csum_replace4(check, skb, oldip, newip, true);
+}
+
+static void nf_nat_ipv6_csum_update(struct sk_buff *skb,
+ unsigned int iphdroff, __sum16 *check,
+ const struct nf_conntrack_tuple *t,
+ enum nf_nat_manip_type maniptype)
+{
+#if IS_ENABLED(CONFIG_IPV6)
+ const struct ipv6hdr *ipv6h = (struct ipv6hdr *)(skb->data + iphdroff);
+ const struct in6_addr *oldip, *newip;
+
+ if (maniptype == NF_NAT_MANIP_SRC) {
+ oldip = &ipv6h->saddr;
+ newip = &t->src.u3.in6;
+ } else {
+ oldip = &ipv6h->daddr;
+ newip = &t->dst.u3.in6;
+ }
+ inet_proto_csum_replace16(check, skb, oldip->s6_addr32,
+ newip->s6_addr32, true);
+#endif
+}
+
+static void nf_csum_update(struct sk_buff *skb,
+ unsigned int iphdroff, __sum16 *check,
+ const struct nf_conntrack_tuple *t,
+ enum nf_nat_manip_type maniptype)
+{
+ switch (t->src.l3num) {
+ case NFPROTO_IPV4:
+ nf_nat_ipv4_csum_update(skb, iphdroff, check, t, maniptype);
+ return;
+ case NFPROTO_IPV6:
+ nf_nat_ipv6_csum_update(skb, iphdroff, check, t, maniptype);
+ return;
+ }
+}
+
+static void nf_nat_ipv4_csum_recalc(struct sk_buff *skb,
+ u8 proto, void *data, __sum16 *check,
+ int datalen, int oldlen)
+{
+ if (skb->ip_summed != CHECKSUM_PARTIAL) {
+ const struct iphdr *iph = ip_hdr(skb);
+
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ skb->csum_start = skb_headroom(skb) + skb_network_offset(skb) +
+ ip_hdrlen(skb);
+ skb->csum_offset = (void *)check - data;
+ *check = ~csum_tcpudp_magic(iph->saddr, iph->daddr, datalen,
+ proto, 0);
+ } else {
+ inet_proto_csum_replace2(check, skb,
+ htons(oldlen), htons(datalen), true);
+ }
+}
+
+#if IS_ENABLED(CONFIG_IPV6)
+static void nf_nat_ipv6_csum_recalc(struct sk_buff *skb,
+ u8 proto, void *data, __sum16 *check,
+ int datalen, int oldlen)
+{
+ if (skb->ip_summed != CHECKSUM_PARTIAL) {
+ const struct ipv6hdr *ipv6h = ipv6_hdr(skb);
+
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ skb->csum_start = skb_headroom(skb) + skb_network_offset(skb) +
+ (data - (void *)skb->data);
+ skb->csum_offset = (void *)check - data;
+ *check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
+ datalen, proto, 0);
+ } else {
+ inet_proto_csum_replace2(check, skb,
+ htons(oldlen), htons(datalen), true);
+ }
+}
+#endif
+
+void nf_nat_csum_recalc(struct sk_buff *skb,
+ u8 nfproto, u8 proto, void *data, __sum16 *check,
+ int datalen, int oldlen)
+{
+ switch (nfproto) {
+ case NFPROTO_IPV4:
+ nf_nat_ipv4_csum_recalc(skb, proto, data, check,
+ datalen, oldlen);
+ return;
+#if IS_ENABLED(CONFIG_IPV6)
+ case NFPROTO_IPV6:
+ nf_nat_ipv6_csum_recalc(skb, proto, data, check,
+ datalen, oldlen);
+ return;
+#endif
+ }
+
+ WARN_ON_ONCE(1);
+}
+
+int nf_nat_icmp_reply_translation(struct sk_buff *skb,
+ struct nf_conn *ct,
+ enum ip_conntrack_info ctinfo,
+ unsigned int hooknum)
+{
+ struct {
+ struct icmphdr icmp;
+ struct iphdr ip;
+ } *inside;
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+ enum nf_nat_manip_type manip = HOOK2MANIP(hooknum);
+ unsigned int hdrlen = ip_hdrlen(skb);
+ struct nf_conntrack_tuple target;
+ unsigned long statusbit;
+
+ WARN_ON(ctinfo != IP_CT_RELATED && ctinfo != IP_CT_RELATED_REPLY);
+
+ if (!skb_make_writable(skb, hdrlen + sizeof(*inside)))
+ return 0;
+ if (nf_ip_checksum(skb, hooknum, hdrlen, 0))
+ return 0;
+
+ inside = (void *)skb->data + hdrlen;
+ if (inside->icmp.type == ICMP_REDIRECT) {
+ if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK)
+ return 0;
+ if (ct->status & IPS_NAT_MASK)
+ return 0;
+ }
+
+ if (manip == NF_NAT_MANIP_SRC)
+ statusbit = IPS_SRC_NAT;
+ else
+ statusbit = IPS_DST_NAT;
+
+ /* Invert if this is reply direction */
+ if (dir == IP_CT_DIR_REPLY)
+ statusbit ^= IPS_NAT_MASK;
+
+ if (!(ct->status & statusbit))
+ return 1;
+
+ if (!nf_nat_ipv4_manip_pkt(skb, hdrlen + sizeof(inside->icmp),
+ &ct->tuplehash[!dir].tuple, !manip))
+ return 0;
+
+ if (skb->ip_summed != CHECKSUM_PARTIAL) {
+ /* Reloading "inside" here since manip_pkt may reallocate */
+ inside = (void *)skb->data + hdrlen;
+ inside->icmp.checksum = 0;
+ inside->icmp.checksum =
+ csum_fold(skb_checksum(skb, hdrlen,
+ skb->len - hdrlen, 0));
+ }
+
+ /* Change outer to look like the reply to an incoming packet */
+ nf_ct_invert_tuple(&target, &ct->tuplehash[!dir].tuple);
+ target.dst.protonum = IPPROTO_ICMP;
+ if (!nf_nat_ipv4_manip_pkt(skb, 0, &target, manip))
+ return 0;
+
+ return 1;
+}
+EXPORT_SYMBOL_GPL(nf_nat_icmp_reply_translation);
+
+static unsigned int
+nf_nat_ipv4_fn(void *priv, struct sk_buff *skb,
+ const struct nf_hook_state *state)
+{
+ struct nf_conn *ct;
+ enum ip_conntrack_info ctinfo;
+
+ ct = nf_ct_get(skb, &ctinfo);
+ if (!ct)
+ return NF_ACCEPT;
+
+ if (ctinfo == IP_CT_RELATED || ctinfo == IP_CT_RELATED_REPLY) {
+ if (ip_hdr(skb)->protocol == IPPROTO_ICMP) {
+ if (!nf_nat_icmp_reply_translation(skb, ct, ctinfo,
+ state->hook))
+ return NF_DROP;
+ else
+ return NF_ACCEPT;
+ }
+ }
+
+ return nf_nat_inet_fn(priv, skb, state);
+}
+
+static unsigned int
+nf_nat_ipv4_in(void *priv, struct sk_buff *skb,
+ const struct nf_hook_state *state)
+{
+ unsigned int ret;
+ __be32 daddr = ip_hdr(skb)->daddr;
+
+ ret = nf_nat_ipv4_fn(priv, skb, state);
+ if (ret == NF_ACCEPT && daddr != ip_hdr(skb)->daddr)
+ skb_dst_drop(skb);
+
+ return ret;
+}
+
+static unsigned int
+nf_nat_ipv4_out(void *priv, struct sk_buff *skb,
+ const struct nf_hook_state *state)
+{
+#ifdef CONFIG_XFRM
+ const struct nf_conn *ct;
+ enum ip_conntrack_info ctinfo;
+ int err;
+#endif
+ unsigned int ret;
+
+ ret = nf_nat_ipv4_fn(priv, skb, state);
+#ifdef CONFIG_XFRM
+ if (ret != NF_ACCEPT)
+ return ret;
+
+ if (IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED)
+ return ret;
+
+ ct = nf_ct_get(skb, &ctinfo);
+ if (ct) {
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+
+ if (ct->tuplehash[dir].tuple.src.u3.ip !=
+ ct->tuplehash[!dir].tuple.dst.u3.ip ||
+ (ct->tuplehash[dir].tuple.dst.protonum != IPPROTO_ICMP &&
+ ct->tuplehash[dir].tuple.src.u.all !=
+ ct->tuplehash[!dir].tuple.dst.u.all)) {
+ err = nf_xfrm_me_harder(state->net, skb, AF_INET);
+ if (err < 0)
+ ret = NF_DROP_ERR(err);
+ }
+ }
+#endif
+ return ret;
+}
+
+static unsigned int
+nf_nat_ipv4_local_fn(void *priv, struct sk_buff *skb,
+ const struct nf_hook_state *state)
+{
+ const struct nf_conn *ct;
+ enum ip_conntrack_info ctinfo;
+ unsigned int ret;
+ int err;
+
+ ret = nf_nat_ipv4_fn(priv, skb, state);
+ if (ret != NF_ACCEPT)
+ return ret;
+
+ ct = nf_ct_get(skb, &ctinfo);
+ if (ct) {
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+
+ if (ct->tuplehash[dir].tuple.dst.u3.ip !=
+ ct->tuplehash[!dir].tuple.src.u3.ip) {
+ err = ip_route_me_harder(state->net, skb, RTN_UNSPEC);
+ if (err < 0)
+ ret = NF_DROP_ERR(err);
+ }
+#ifdef CONFIG_XFRM
+ else if (!(IPCB(skb)->flags & IPSKB_XFRM_TRANSFORMED) &&
+ ct->tuplehash[dir].tuple.dst.protonum != IPPROTO_ICMP &&
+ ct->tuplehash[dir].tuple.dst.u.all !=
+ ct->tuplehash[!dir].tuple.src.u.all) {
+ err = nf_xfrm_me_harder(state->net, skb, AF_INET);
+ if (err < 0)
+ ret = NF_DROP_ERR(err);
+ }
+#endif
+ }
+ return ret;
+}
+
+static const struct nf_hook_ops nf_nat_ipv4_ops[] = {
+ /* Before packet filtering, change destination */
+ {
+ .hook = nf_nat_ipv4_in,
+ .pf = NFPROTO_IPV4,
+ .hooknum = NF_INET_PRE_ROUTING,
+ .priority = NF_IP_PRI_NAT_DST,
+ },
+ /* After packet filtering, change source */
+ {
+ .hook = nf_nat_ipv4_out,
+ .pf = NFPROTO_IPV4,
+ .hooknum = NF_INET_POST_ROUTING,
+ .priority = NF_IP_PRI_NAT_SRC,
+ },
+ /* Before packet filtering, change destination */
+ {
+ .hook = nf_nat_ipv4_local_fn,
+ .pf = NFPROTO_IPV4,
+ .hooknum = NF_INET_LOCAL_OUT,
+ .priority = NF_IP_PRI_NAT_DST,
+ },
+ /* After packet filtering, change source */
+ {
+ .hook = nf_nat_ipv4_fn,
+ .pf = NFPROTO_IPV4,
+ .hooknum = NF_INET_LOCAL_IN,
+ .priority = NF_IP_PRI_NAT_SRC,
+ },
+};
+
+int nf_nat_ipv4_register_fn(struct net *net, const struct nf_hook_ops *ops)
+{
+ return nf_nat_register_fn(net, ops, nf_nat_ipv4_ops, ARRAY_SIZE(nf_nat_ipv4_ops));
+}
+EXPORT_SYMBOL_GPL(nf_nat_ipv4_register_fn);
+
+void nf_nat_ipv4_unregister_fn(struct net *net, const struct nf_hook_ops *ops)
+{
+ nf_nat_unregister_fn(net, ops, ARRAY_SIZE(nf_nat_ipv4_ops));
+}
+EXPORT_SYMBOL_GPL(nf_nat_ipv4_unregister_fn);
+
+#if IS_ENABLED(CONFIG_IPV6)
+int nf_nat_icmpv6_reply_translation(struct sk_buff *skb,
+ struct nf_conn *ct,
+ enum ip_conntrack_info ctinfo,
+ unsigned int hooknum,
+ unsigned int hdrlen)
+{
+ struct {
+ struct icmp6hdr icmp6;
+ struct ipv6hdr ip6;
+ } *inside;
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+ enum nf_nat_manip_type manip = HOOK2MANIP(hooknum);
+ struct nf_conntrack_tuple target;
+ unsigned long statusbit;
+
+ WARN_ON(ctinfo != IP_CT_RELATED && ctinfo != IP_CT_RELATED_REPLY);
+
+ if (!skb_make_writable(skb, hdrlen + sizeof(*inside)))
+ return 0;
+ if (nf_ip6_checksum(skb, hooknum, hdrlen, IPPROTO_ICMPV6))
+ return 0;
+
+ inside = (void *)skb->data + hdrlen;
+ if (inside->icmp6.icmp6_type == NDISC_REDIRECT) {
+ if ((ct->status & IPS_NAT_DONE_MASK) != IPS_NAT_DONE_MASK)
+ return 0;
+ if (ct->status & IPS_NAT_MASK)
+ return 0;
+ }
+
+ if (manip == NF_NAT_MANIP_SRC)
+ statusbit = IPS_SRC_NAT;
+ else
+ statusbit = IPS_DST_NAT;
+
+ /* Invert if this is reply direction */
+ if (dir == IP_CT_DIR_REPLY)
+ statusbit ^= IPS_NAT_MASK;
+
+ if (!(ct->status & statusbit))
+ return 1;
+
+ if (!nf_nat_ipv6_manip_pkt(skb, hdrlen + sizeof(inside->icmp6),
+ &ct->tuplehash[!dir].tuple, !manip))
+ return 0;
+
+ if (skb->ip_summed != CHECKSUM_PARTIAL) {
+ struct ipv6hdr *ipv6h = ipv6_hdr(skb);
+
+ inside = (void *)skb->data + hdrlen;
+ inside->icmp6.icmp6_cksum = 0;
+ inside->icmp6.icmp6_cksum =
+ csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr,
+ skb->len - hdrlen, IPPROTO_ICMPV6,
+ skb_checksum(skb, hdrlen,
+ skb->len - hdrlen, 0));
+ }
+
+ nf_ct_invert_tuple(&target, &ct->tuplehash[!dir].tuple);
+ target.dst.protonum = IPPROTO_ICMPV6;
+ if (!nf_nat_ipv6_manip_pkt(skb, 0, &target, manip))
+ return 0;
+
+ return 1;
+}
+EXPORT_SYMBOL_GPL(nf_nat_icmpv6_reply_translation);
+
+static unsigned int
+nf_nat_ipv6_fn(void *priv, struct sk_buff *skb,
+ const struct nf_hook_state *state)
+{
+ struct nf_conn *ct;
+ enum ip_conntrack_info ctinfo;
+ __be16 frag_off;
+ int hdrlen;
+ u8 nexthdr;
+
+ ct = nf_ct_get(skb, &ctinfo);
+ /* Can't track? It's not due to stress, or conntrack would
+ * have dropped it. Hence it's the user's responsibilty to
+ * packet filter it out, or implement conntrack/NAT for that
+ * protocol. 8) --RR
+ */
+ if (!ct)
+ return NF_ACCEPT;
+
+ if (ctinfo == IP_CT_RELATED || ctinfo == IP_CT_RELATED_REPLY) {
+ nexthdr = ipv6_hdr(skb)->nexthdr;
+ hdrlen = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr),
+ &nexthdr, &frag_off);
+
+ if (hdrlen >= 0 && nexthdr == IPPROTO_ICMPV6) {
+ if (!nf_nat_icmpv6_reply_translation(skb, ct, ctinfo,
+ state->hook,
+ hdrlen))
+ return NF_DROP;
+ else
+ return NF_ACCEPT;
+ }
+ }
+
+ return nf_nat_inet_fn(priv, skb, state);
+}
+
+static unsigned int
+nf_nat_ipv6_in(void *priv, struct sk_buff *skb,
+ const struct nf_hook_state *state)
+{
+ unsigned int ret;
+ struct in6_addr daddr = ipv6_hdr(skb)->daddr;
+
+ ret = nf_nat_ipv6_fn(priv, skb, state);
+ if (ret != NF_DROP && ret != NF_STOLEN &&
+ ipv6_addr_cmp(&daddr, &ipv6_hdr(skb)->daddr))
+ skb_dst_drop(skb);
+
+ return ret;
+}
+
+static unsigned int
+nf_nat_ipv6_out(void *priv, struct sk_buff *skb,
+ const struct nf_hook_state *state)
+{
+#ifdef CONFIG_XFRM
+ const struct nf_conn *ct;
+ enum ip_conntrack_info ctinfo;
+ int err;
+#endif
+ unsigned int ret;
+
+ ret = nf_nat_ipv6_fn(priv, skb, state);
+#ifdef CONFIG_XFRM
+ if (ret != NF_ACCEPT)
+ return ret;
+
+ if (IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED)
+ return ret;
+ ct = nf_ct_get(skb, &ctinfo);
+ if (ct) {
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+
+ if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.src.u3,
+ &ct->tuplehash[!dir].tuple.dst.u3) ||
+ (ct->tuplehash[dir].tuple.dst.protonum != IPPROTO_ICMPV6 &&
+ ct->tuplehash[dir].tuple.src.u.all !=
+ ct->tuplehash[!dir].tuple.dst.u.all)) {
+ err = nf_xfrm_me_harder(state->net, skb, AF_INET6);
+ if (err < 0)
+ ret = NF_DROP_ERR(err);
+ }
+ }
+#endif
+
+ return ret;
+}
+
+static int nat_route_me_harder(struct net *net, struct sk_buff *skb)
+{
+#ifdef CONFIG_IPV6_MODULE
+ const struct nf_ipv6_ops *v6_ops = nf_get_ipv6_ops();
+
+ if (!v6_ops)
+ return -EHOSTUNREACH;
+
+ return v6_ops->route_me_harder(net, skb);
+#else
+ return ip6_route_me_harder(net, skb);
+#endif
+}
+
+static unsigned int
+nf_nat_ipv6_local_fn(void *priv, struct sk_buff *skb,
+ const struct nf_hook_state *state)
+{
+ const struct nf_conn *ct;
+ enum ip_conntrack_info ctinfo;
+ unsigned int ret;
+ int err;
+
+ ret = nf_nat_ipv6_fn(priv, skb, state);
+ if (ret != NF_ACCEPT)
+ return ret;
+
+ ct = nf_ct_get(skb, &ctinfo);
+ if (ct) {
+ enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
+
+ if (!nf_inet_addr_cmp(&ct->tuplehash[dir].tuple.dst.u3,
+ &ct->tuplehash[!dir].tuple.src.u3)) {
+ err = nat_route_me_harder(state->net, skb);
+ if (err < 0)
+ ret = NF_DROP_ERR(err);
+ }
+#ifdef CONFIG_XFRM
+ else if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
+ ct->tuplehash[dir].tuple.dst.protonum != IPPROTO_ICMPV6 &&
+ ct->tuplehash[dir].tuple.dst.u.all !=
+ ct->tuplehash[!dir].tuple.src.u.all) {
+ err = nf_xfrm_me_harder(state->net, skb, AF_INET6);
+ if (err < 0)
+ ret = NF_DROP_ERR(err);
+ }
+#endif
+ }
+
+ return ret;
+}
+
+static const struct nf_hook_ops nf_nat_ipv6_ops[] = {
+ /* Before packet filtering, change destination */
+ {
+ .hook = nf_nat_ipv6_in,
+ .pf = NFPROTO_IPV6,
+ .hooknum = NF_INET_PRE_ROUTING,
+ .priority = NF_IP6_PRI_NAT_DST,
+ },
+ /* After packet filtering, change source */
+ {
+ .hook = nf_nat_ipv6_out,
+ .pf = NFPROTO_IPV6,
+ .hooknum = NF_INET_POST_ROUTING,
+ .priority = NF_IP6_PRI_NAT_SRC,
+ },
+ /* Before packet filtering, change destination */
+ {
+ .hook = nf_nat_ipv6_local_fn,
+ .pf = NFPROTO_IPV6,
+ .hooknum = NF_INET_LOCAL_OUT,
+ .priority = NF_IP6_PRI_NAT_DST,
+ },
+ /* After packet filtering, change source */
+ {
+ .hook = nf_nat_ipv6_fn,
+ .pf = NFPROTO_IPV6,
+ .hooknum = NF_INET_LOCAL_IN,
+ .priority = NF_IP6_PRI_NAT_SRC,
+ },
+};
+
+int nf_nat_ipv6_register_fn(struct net *net, const struct nf_hook_ops *ops)
+{
+ return nf_nat_register_fn(net, ops, nf_nat_ipv6_ops,
+ ARRAY_SIZE(nf_nat_ipv6_ops));
+}
+EXPORT_SYMBOL_GPL(nf_nat_ipv6_register_fn);
+
+void nf_nat_ipv6_unregister_fn(struct net *net, const struct nf_hook_ops *ops)
+{
+ nf_nat_unregister_fn(net, ops, ARRAY_SIZE(nf_nat_ipv6_ops));
+}
+EXPORT_SYMBOL_GPL(nf_nat_ipv6_unregister_fn);
+#endif /* CONFIG_IPV6 */
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.