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netfilter: flowtable: fast NAT functions never fail

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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>
This commit is contained in:
Pablo Neira Ayuso 2021-03-17 15:55:25 +01:00
parent 4f08f173d0
commit f4401262b9
3 changed files with 84 additions and 116 deletions
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12
include/net/netfilter/nf_flow_table.h
View File

@ -229,12 +229,12 @@ void nf_flow_table_free(struct nf_flowtable *flow_table);
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;

41
net/netfilter/nf_flow_table_core.c
View File

@ -389,20 +389,17 @@ static void nf_flow_offload_work_gc(struct work_struct *work)
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;
@ -413,30 +410,24 @@ static int nf_flow_nat_port_udp(struct sk_buff *skb, unsigned int thoff,
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;
@ -456,13 +447,13 @@ int nf_flow_snat_port(const struct flow_offload *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;
@ -482,7 +473,7 @@ int nf_flow_dnat_port(const struct flow_offload *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);

147
net/netfilter/nf_flow_table_ip.c
View File

@ -34,19 +34,17 @@ static int nf_flow_state_check(struct flow_offload *flow, int proto,
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_buff *skb, unsigned int thoff,
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 flow_offload *flow, struct sk_buff *skb,
}
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 flow_offload *flow, struct sk_buff *skb,
}
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, struct sk_buff *skb,
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, struct sk_buff *skb,
}
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 sk_buff *skb, unsigned int thoff,
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 struct flow_offload *flow,
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 struct flow_offload *flow,
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, struct sk_buff *skb,
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;