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openwrt/target/linux/generic/backport-5.10/610-v5.13-07-netfilter-flow...

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From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Tue, 23 Mar 2021 00:56:25 +0100
Subject: [PATCH] netfilter: flowtable: fast NAT functions never fail
Simplify existing fast NAT routines by returning void. After the
skb_try_make_writable() call consolidation, these routines cannot ever
fail.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
--- a/include/net/netfilter/nf_flow_table.h
+++ b/include/net/netfilter/nf_flow_table.h
@@ -228,12 +228,12 @@ void nf_flow_table_free(struct nf_flowta
void flow_offload_teardown(struct flow_offload *flow);
-int nf_flow_snat_port(const struct flow_offload *flow,
- struct sk_buff *skb, unsigned int thoff,
- u8 protocol, enum flow_offload_tuple_dir dir);
-int nf_flow_dnat_port(const struct flow_offload *flow,
- struct sk_buff *skb, unsigned int thoff,
- u8 protocol, enum flow_offload_tuple_dir dir);
+void nf_flow_snat_port(const struct flow_offload *flow,
+ struct sk_buff *skb, unsigned int thoff,
+ u8 protocol, enum flow_offload_tuple_dir dir);
+void nf_flow_dnat_port(const struct flow_offload *flow,
+ struct sk_buff *skb, unsigned int thoff,
+ u8 protocol, enum flow_offload_tuple_dir dir);
struct flow_ports {
__be16 source, dest;
--- a/net/netfilter/nf_flow_table_core.c
+++ b/net/netfilter/nf_flow_table_core.c
@@ -388,20 +388,17 @@ static void nf_flow_offload_work_gc(stru
queue_delayed_work(system_power_efficient_wq, &flow_table->gc_work, HZ);
}
-
-static int nf_flow_nat_port_tcp(struct sk_buff *skb, unsigned int thoff,
- __be16 port, __be16 new_port)
+static void nf_flow_nat_port_tcp(struct sk_buff *skb, unsigned int thoff,
+ __be16 port, __be16 new_port)
{
struct tcphdr *tcph;
tcph = (void *)(skb_network_header(skb) + thoff);
inet_proto_csum_replace2(&tcph->check, skb, port, new_port, false);
-
- return 0;
}
-static int nf_flow_nat_port_udp(struct sk_buff *skb, unsigned int thoff,
- __be16 port, __be16 new_port)
+static void nf_flow_nat_port_udp(struct sk_buff *skb, unsigned int thoff,
+ __be16 port, __be16 new_port)
{
struct udphdr *udph;
@@ -412,30 +409,24 @@ static int nf_flow_nat_port_udp(struct s
if (!udph->check)
udph->check = CSUM_MANGLED_0;
}
-
- return 0;
}
-static int nf_flow_nat_port(struct sk_buff *skb, unsigned int thoff,
- u8 protocol, __be16 port, __be16 new_port)
+static void nf_flow_nat_port(struct sk_buff *skb, unsigned int thoff,
+ u8 protocol, __be16 port, __be16 new_port)
{
switch (protocol) {
case IPPROTO_TCP:
- if (nf_flow_nat_port_tcp(skb, thoff, port, new_port) < 0)
- return NF_DROP;
+ nf_flow_nat_port_tcp(skb, thoff, port, new_port);
break;
case IPPROTO_UDP:
- if (nf_flow_nat_port_udp(skb, thoff, port, new_port) < 0)
- return NF_DROP;
+ nf_flow_nat_port_udp(skb, thoff, port, new_port);
break;
}
-
- return 0;
}
-int nf_flow_snat_port(const struct flow_offload *flow,
- struct sk_buff *skb, unsigned int thoff,
- u8 protocol, enum flow_offload_tuple_dir dir)
+void nf_flow_snat_port(const struct flow_offload *flow,
+ struct sk_buff *skb, unsigned int thoff,
+ u8 protocol, enum flow_offload_tuple_dir dir)
{
struct flow_ports *hdr;
__be16 port, new_port;
@@ -455,13 +446,13 @@ int nf_flow_snat_port(const struct flow_
break;
}
- return nf_flow_nat_port(skb, thoff, protocol, port, new_port);
+ nf_flow_nat_port(skb, thoff, protocol, port, new_port);
}
EXPORT_SYMBOL_GPL(nf_flow_snat_port);
-int nf_flow_dnat_port(const struct flow_offload *flow,
- struct sk_buff *skb, unsigned int thoff,
- u8 protocol, enum flow_offload_tuple_dir dir)
+void nf_flow_dnat_port(const struct flow_offload *flow, struct sk_buff *skb,
+ unsigned int thoff, u8 protocol,
+ enum flow_offload_tuple_dir dir)
{
struct flow_ports *hdr;
__be16 port, new_port;
@@ -481,7 +472,7 @@ int nf_flow_dnat_port(const struct flow_
break;
}
- return nf_flow_nat_port(skb, thoff, protocol, port, new_port);
+ nf_flow_nat_port(skb, thoff, protocol, port, new_port);
}
EXPORT_SYMBOL_GPL(nf_flow_dnat_port);
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -34,19 +34,17 @@ static int nf_flow_state_check(struct fl
return 0;
}
-static int nf_flow_nat_ip_tcp(struct sk_buff *skb, unsigned int thoff,
- __be32 addr, __be32 new_addr)
+static void nf_flow_nat_ip_tcp(struct sk_buff *skb, unsigned int thoff,
+ __be32 addr, __be32 new_addr)
{
struct tcphdr *tcph;
tcph = (void *)(skb_network_header(skb) + thoff);
inet_proto_csum_replace4(&tcph->check, skb, addr, new_addr, true);
-
- return 0;
}
-static int nf_flow_nat_ip_udp(struct sk_buff *skb, unsigned int thoff,
- __be32 addr, __be32 new_addr)
+static void nf_flow_nat_ip_udp(struct sk_buff *skb, unsigned int thoff,
+ __be32 addr, __be32 new_addr)
{
struct udphdr *udph;
@@ -57,31 +55,25 @@ static int nf_flow_nat_ip_udp(struct sk_
if (!udph->check)
udph->check = CSUM_MANGLED_0;
}
-
- return 0;
}
-static int nf_flow_nat_ip_l4proto(struct sk_buff *skb, struct iphdr *iph,
- unsigned int thoff, __be32 addr,
- __be32 new_addr)
+static void nf_flow_nat_ip_l4proto(struct sk_buff *skb, struct iphdr *iph,
+ unsigned int thoff, __be32 addr,
+ __be32 new_addr)
{
switch (iph->protocol) {
case IPPROTO_TCP:
- if (nf_flow_nat_ip_tcp(skb, thoff, addr, new_addr) < 0)
- return NF_DROP;
+ nf_flow_nat_ip_tcp(skb, thoff, addr, new_addr);
break;
case IPPROTO_UDP:
- if (nf_flow_nat_ip_udp(skb, thoff, addr, new_addr) < 0)
- return NF_DROP;
+ nf_flow_nat_ip_udp(skb, thoff, addr, new_addr);
break;
}
-
- return 0;
}
-static int nf_flow_snat_ip(const struct flow_offload *flow, struct sk_buff *skb,
- struct iphdr *iph, unsigned int thoff,
- enum flow_offload_tuple_dir dir)
+static void nf_flow_snat_ip(const struct flow_offload *flow,
+ struct sk_buff *skb, struct iphdr *iph,
+ unsigned int thoff, enum flow_offload_tuple_dir dir)
{
__be32 addr, new_addr;
@@ -99,12 +91,12 @@ static int nf_flow_snat_ip(const struct
}
csum_replace4(&iph->check, addr, new_addr);
- return nf_flow_nat_ip_l4proto(skb, iph, thoff, addr, new_addr);
+ nf_flow_nat_ip_l4proto(skb, iph, thoff, addr, new_addr);
}
-static int nf_flow_dnat_ip(const struct flow_offload *flow, struct sk_buff *skb,
- struct iphdr *iph, unsigned int thoff,
- enum flow_offload_tuple_dir dir)
+static void nf_flow_dnat_ip(const struct flow_offload *flow,
+ struct sk_buff *skb, struct iphdr *iph,
+ unsigned int thoff, enum flow_offload_tuple_dir dir)
{
__be32 addr, new_addr;
@@ -122,24 +114,21 @@ static int nf_flow_dnat_ip(const struct
}
csum_replace4(&iph->check, addr, new_addr);
- return nf_flow_nat_ip_l4proto(skb, iph, thoff, addr, new_addr);
+ nf_flow_nat_ip_l4proto(skb, iph, thoff, addr, new_addr);
}
-static int nf_flow_nat_ip(const struct flow_offload *flow, struct sk_buff *skb,
+static void nf_flow_nat_ip(const struct flow_offload *flow, struct sk_buff *skb,
unsigned int thoff, enum flow_offload_tuple_dir dir,
struct iphdr *iph)
{
- if (test_bit(NF_FLOW_SNAT, &flow->flags) &&
- (nf_flow_snat_port(flow, skb, thoff, iph->protocol, dir) < 0 ||
- nf_flow_snat_ip(flow, skb, iph, thoff, dir) < 0))
- return -1;
-
- if (test_bit(NF_FLOW_DNAT, &flow->flags) &&
- (nf_flow_dnat_port(flow, skb, thoff, iph->protocol, dir) < 0 ||
- nf_flow_dnat_ip(flow, skb, iph, thoff, dir) < 0))
- return -1;
-
- return 0;
+ if (test_bit(NF_FLOW_SNAT, &flow->flags)) {
+ nf_flow_snat_port(flow, skb, thoff, iph->protocol, dir);
+ nf_flow_snat_ip(flow, skb, iph, thoff, dir);
+ }
+ if (test_bit(NF_FLOW_DNAT, &flow->flags)) {
+ nf_flow_dnat_port(flow, skb, thoff, iph->protocol, dir);
+ nf_flow_dnat_ip(flow, skb, iph, thoff, dir);
+ }
}
static bool ip_has_options(unsigned int thoff)
@@ -276,8 +265,7 @@ nf_flow_offload_ip_hook(void *priv, stru
return NF_DROP;
iph = ip_hdr(skb);
- if (nf_flow_nat_ip(flow, skb, thoff, dir, iph) < 0)
- return NF_DROP;
+ nf_flow_nat_ip(flow, skb, thoff, dir, iph);
ip_decrease_ttl(iph);
skb->tstamp = 0;
@@ -301,22 +289,21 @@ nf_flow_offload_ip_hook(void *priv, stru
}
EXPORT_SYMBOL_GPL(nf_flow_offload_ip_hook);
-static int nf_flow_nat_ipv6_tcp(struct sk_buff *skb, unsigned int thoff,
- struct in6_addr *addr,
- struct in6_addr *new_addr)
+static void nf_flow_nat_ipv6_tcp(struct sk_buff *skb, unsigned int thoff,
+ struct in6_addr *addr,
+ struct in6_addr *new_addr,
+ struct ipv6hdr *ip6h)
{
struct tcphdr *tcph;
tcph = (void *)(skb_network_header(skb) + thoff);
inet_proto_csum_replace16(&tcph->check, skb, addr->s6_addr32,
new_addr->s6_addr32, true);
-
- return 0;
}
-static int nf_flow_nat_ipv6_udp(struct sk_buff *skb, unsigned int thoff,
- struct in6_addr *addr,
- struct in6_addr *new_addr)
+static void nf_flow_nat_ipv6_udp(struct sk_buff *skb, unsigned int thoff,
+ struct in6_addr *addr,
+ struct in6_addr *new_addr)
{
struct udphdr *udph;
@@ -327,32 +314,26 @@ static int nf_flow_nat_ipv6_udp(struct s
if (!udph->check)
udph->check = CSUM_MANGLED_0;
}
-
- return 0;
}
-static int nf_flow_nat_ipv6_l4proto(struct sk_buff *skb, struct ipv6hdr *ip6h,
- unsigned int thoff, struct in6_addr *addr,
- struct in6_addr *new_addr)
+static void nf_flow_nat_ipv6_l4proto(struct sk_buff *skb, struct ipv6hdr *ip6h,
+ unsigned int thoff, struct in6_addr *addr,
+ struct in6_addr *new_addr)
{
switch (ip6h->nexthdr) {
case IPPROTO_TCP:
- if (nf_flow_nat_ipv6_tcp(skb, thoff, addr, new_addr) < 0)
- return NF_DROP;
+ nf_flow_nat_ipv6_tcp(skb, thoff, addr, new_addr, ip6h);
break;
case IPPROTO_UDP:
- if (nf_flow_nat_ipv6_udp(skb, thoff, addr, new_addr) < 0)
- return NF_DROP;
+ nf_flow_nat_ipv6_udp(skb, thoff, addr, new_addr);
break;
}
-
- return 0;
}
-static int nf_flow_snat_ipv6(const struct flow_offload *flow,
- struct sk_buff *skb, struct ipv6hdr *ip6h,
- unsigned int thoff,
- enum flow_offload_tuple_dir dir)
+static void nf_flow_snat_ipv6(const struct flow_offload *flow,
+ struct sk_buff *skb, struct ipv6hdr *ip6h,
+ unsigned int thoff,
+ enum flow_offload_tuple_dir dir)
{
struct in6_addr addr, new_addr;
@@ -369,13 +350,13 @@ static int nf_flow_snat_ipv6(const struc
break;
}
- return nf_flow_nat_ipv6_l4proto(skb, ip6h, thoff, &addr, &new_addr);
+ nf_flow_nat_ipv6_l4proto(skb, ip6h, thoff, &addr, &new_addr);
}
-static int nf_flow_dnat_ipv6(const struct flow_offload *flow,
- struct sk_buff *skb, struct ipv6hdr *ip6h,
- unsigned int thoff,
- enum flow_offload_tuple_dir dir)
+static void nf_flow_dnat_ipv6(const struct flow_offload *flow,
+ struct sk_buff *skb, struct ipv6hdr *ip6h,
+ unsigned int thoff,
+ enum flow_offload_tuple_dir dir)
{
struct in6_addr addr, new_addr;
@@ -392,27 +373,24 @@ static int nf_flow_dnat_ipv6(const struc
break;
}
- return nf_flow_nat_ipv6_l4proto(skb, ip6h, thoff, &addr, &new_addr);
+ nf_flow_nat_ipv6_l4proto(skb, ip6h, thoff, &addr, &new_addr);
}
-static int nf_flow_nat_ipv6(const struct flow_offload *flow,
- struct sk_buff *skb,
- enum flow_offload_tuple_dir dir,
- struct ipv6hdr *ip6h)
+static void nf_flow_nat_ipv6(const struct flow_offload *flow,
+ struct sk_buff *skb,
+ enum flow_offload_tuple_dir dir,
+ struct ipv6hdr *ip6h)
{
unsigned int thoff = sizeof(*ip6h);
- if (test_bit(NF_FLOW_SNAT, &flow->flags) &&
- (nf_flow_snat_port(flow, skb, thoff, ip6h->nexthdr, dir) < 0 ||
- nf_flow_snat_ipv6(flow, skb, ip6h, thoff, dir) < 0))
- return -1;
-
- if (test_bit(NF_FLOW_DNAT, &flow->flags) &&
- (nf_flow_dnat_port(flow, skb, thoff, ip6h->nexthdr, dir) < 0 ||
- nf_flow_dnat_ipv6(flow, skb, ip6h, thoff, dir) < 0))
- return -1;
-
- return 0;
+ if (test_bit(NF_FLOW_SNAT, &flow->flags)) {
+ nf_flow_snat_port(flow, skb, thoff, ip6h->nexthdr, dir);
+ nf_flow_snat_ipv6(flow, skb, ip6h, thoff, dir);
+ }
+ if (test_bit(NF_FLOW_DNAT, &flow->flags)) {
+ nf_flow_dnat_port(flow, skb, thoff, ip6h->nexthdr, dir);
+ nf_flow_dnat_ipv6(flow, skb, ip6h, thoff, dir);
+ }
}
static int nf_flow_tuple_ipv6(struct sk_buff *skb, const struct net_device *dev,
@@ -507,8 +485,7 @@ nf_flow_offload_ipv6_hook(void *priv, st
return NF_DROP;
ip6h = ipv6_hdr(skb);
- if (nf_flow_nat_ipv6(flow, skb, dir, ip6h) < 0)
- return NF_DROP;
+ nf_flow_nat_ipv6(flow, skb, dir, ip6h);
ip6h->hop_limit--;
skb->tstamp = 0;
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