* [PATCH nf-next] netfilter: flowtable: reduce calls to pskb_may_pull()
@ 2020-10-11 22:18 Pablo Neira Ayuso
0 siblings, 0 replies; only message in thread
From: Pablo Neira Ayuso @ 2020-10-11 22:18 UTC (permalink / raw)
To: netfilter-devel
Make two unfront calls to pskb_may_pull() to linearize the network and
transport header.
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
net/netfilter/nf_flow_table_core.c | 12 +++-----
net/netfilter/nf_flow_table_ip.c | 45 +++++++++++++++++-------------
2 files changed, 30 insertions(+), 27 deletions(-)
diff --git a/net/netfilter/nf_flow_table_core.c b/net/netfilter/nf_flow_table_core.c
index 4f7a567c536e..513f78db3cb2 100644
--- a/net/netfilter/nf_flow_table_core.c
+++ b/net/netfilter/nf_flow_table_core.c
@@ -395,8 +395,7 @@ static int nf_flow_nat_port_tcp(struct sk_buff *skb, unsigned int thoff,
{
struct tcphdr *tcph;
- if (!pskb_may_pull(skb, thoff + sizeof(*tcph)) ||
- skb_try_make_writable(skb, thoff + sizeof(*tcph)))
+ if (skb_try_make_writable(skb, thoff + sizeof(*tcph)))
return -1;
tcph = (void *)(skb_network_header(skb) + thoff);
@@ -410,8 +409,7 @@ static int nf_flow_nat_port_udp(struct sk_buff *skb, unsigned int thoff,
{
struct udphdr *udph;
- if (!pskb_may_pull(skb, thoff + sizeof(*udph)) ||
- skb_try_make_writable(skb, thoff + sizeof(*udph)))
+ if (skb_try_make_writable(skb, thoff + sizeof(*udph)))
return -1;
udph = (void *)(skb_network_header(skb) + thoff);
@@ -449,8 +447,7 @@ int nf_flow_snat_port(const struct flow_offload *flow,
struct flow_ports *hdr;
__be16 port, new_port;
- if (!pskb_may_pull(skb, thoff + sizeof(*hdr)) ||
- skb_try_make_writable(skb, thoff + sizeof(*hdr)))
+ if (skb_try_make_writable(skb, thoff + sizeof(*hdr)))
return -1;
hdr = (void *)(skb_network_header(skb) + thoff);
@@ -481,8 +478,7 @@ int nf_flow_dnat_port(const struct flow_offload *flow,
struct flow_ports *hdr;
__be16 port, new_port;
- if (!pskb_may_pull(skb, thoff + sizeof(*hdr)) ||
- skb_try_make_writable(skb, thoff + sizeof(*hdr)))
+ if (skb_try_make_writable(skb, thoff + sizeof(*hdr)))
return -1;
hdr = (void *)(skb_network_header(skb) + thoff);
diff --git a/net/netfilter/nf_flow_table_ip.c b/net/netfilter/nf_flow_table_ip.c
index a3bca758b849..a698dbe28ef5 100644
--- a/net/netfilter/nf_flow_table_ip.c
+++ b/net/netfilter/nf_flow_table_ip.c
@@ -25,9 +25,6 @@ static int nf_flow_state_check(struct flow_offload *flow, int proto,
if (proto != IPPROTO_TCP)
return 0;
- if (!pskb_may_pull(skb, thoff + sizeof(*tcph)))
- return -1;
-
tcph = (void *)(skb_network_header(skb) + thoff);
if (unlikely(tcph->fin || tcph->rst)) {
flow_offload_teardown(flow);
@@ -42,8 +39,7 @@ static int nf_flow_nat_ip_tcp(struct sk_buff *skb, unsigned int thoff,
{
struct tcphdr *tcph;
- if (!pskb_may_pull(skb, thoff + sizeof(*tcph)) ||
- skb_try_make_writable(skb, thoff + sizeof(*tcph)))
+ if (skb_try_make_writable(skb, thoff + sizeof(*tcph)))
return -1;
tcph = (void *)(skb_network_header(skb) + thoff);
@@ -57,8 +53,7 @@ static int nf_flow_nat_ip_udp(struct sk_buff *skb, unsigned int thoff,
{
struct udphdr *udph;
- if (!pskb_may_pull(skb, thoff + sizeof(*udph)) ||
- skb_try_make_writable(skb, thoff + sizeof(*udph)))
+ if (skb_try_make_writable(skb, thoff + sizeof(*udph)))
return -1;
udph = (void *)(skb_network_header(skb) + thoff);
@@ -167,8 +162,8 @@ static bool ip_has_options(unsigned int thoff)
static int nf_flow_tuple_ip(struct sk_buff *skb, const struct net_device *dev,
struct flow_offload_tuple *tuple)
{
+ unsigned int thoff, hdrsize;
struct flow_ports *ports;
- unsigned int thoff;
struct iphdr *iph;
if (!pskb_may_pull(skb, sizeof(*iph)))
@@ -181,15 +176,22 @@ static int nf_flow_tuple_ip(struct sk_buff *skb, const struct net_device *dev,
unlikely(ip_has_options(thoff)))
return -1;
- if (iph->protocol != IPPROTO_TCP &&
- iph->protocol != IPPROTO_UDP)
+ switch (iph->protocol) {
+ case IPPROTO_TCP:
+ hdrsize = sizeof(struct tcphdr);
+ break;
+ case IPPROTO_UDP:
+ hdrsize = sizeof(struct udphdr);
+ break;
+ default:
return -1;
+ }
if (iph->ttl <= 1)
return -1;
thoff = iph->ihl * 4;
- if (!pskb_may_pull(skb, thoff + sizeof(*ports)))
+ if (!pskb_may_pull(skb, thoff + hdrsize))
return -1;
iph = ip_hdr(skb);
@@ -315,8 +317,7 @@ static int nf_flow_nat_ipv6_tcp(struct sk_buff *skb, unsigned int thoff,
{
struct tcphdr *tcph;
- if (!pskb_may_pull(skb, thoff + sizeof(*tcph)) ||
- skb_try_make_writable(skb, thoff + sizeof(*tcph)))
+ if (skb_try_make_writable(skb, thoff + sizeof(*tcph)))
return -1;
tcph = (void *)(skb_network_header(skb) + thoff);
@@ -332,8 +333,7 @@ static int nf_flow_nat_ipv6_udp(struct sk_buff *skb, unsigned int thoff,
{
struct udphdr *udph;
- if (!pskb_may_pull(skb, thoff + sizeof(*udph)) ||
- skb_try_make_writable(skb, thoff + sizeof(*udph)))
+ if (skb_try_make_writable(skb, thoff + sizeof(*udph)))
return -1;
udph = (void *)(skb_network_header(skb) + thoff);
@@ -439,24 +439,31 @@ static int nf_flow_nat_ipv6(const struct flow_offload *flow,
static int nf_flow_tuple_ipv6(struct sk_buff *skb, const struct net_device *dev,
struct flow_offload_tuple *tuple)
{
+ unsigned int thoff, hdrsize;
struct flow_ports *ports;
struct ipv6hdr *ip6h;
- unsigned int thoff;
if (!pskb_may_pull(skb, sizeof(*ip6h)))
return -1;
ip6h = ipv6_hdr(skb);
- if (ip6h->nexthdr != IPPROTO_TCP &&
- ip6h->nexthdr != IPPROTO_UDP)
+ switch (ip6h->nexthdr) {
+ case IPPROTO_TCP:
+ hdrsize = sizeof(struct tcphdr);
+ break;
+ case IPPROTO_UDP:
+ hdrsize = sizeof(struct udphdr);
+ break;
+ default:
return -1;
+ }
if (ip6h->hop_limit <= 1)
return -1;
thoff = sizeof(*ip6h);
- if (!pskb_may_pull(skb, thoff + sizeof(*ports)))
+ if (!pskb_may_pull(skb, thoff + hdrsize))
return -1;
ip6h = ipv6_hdr(skb);
--
2.20.1
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