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netfilter: nf_flow_table: tear down TCP flows if RST or FIN was seen

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Allow the slow path to handle the shutdown of the connection with proper
timeouts. The packet containing RST/FIN is also sent to the slow path
and the TCP conntrack module will update its state.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Felix Fietkau 2018-02-26 10:15:24 +01:00 • committed by Pablo Neira Ayuso
parent da5984e510
commit b6f27d322a
1 changed files with 27 additions and 3 deletions
Download patch file Download diff file Expand all files Collapse all files

30
net/netfilter/nf_flow_table_ip.c
View file

@ -15,6 +15,23 @@
#include <linux/tcp.h> #include <linux/tcp.h>
#include <linux/udp.h> #include <linux/udp.h>
static int nf_flow_tcp_state_check(struct flow_offload *flow,
struct sk_buff *skb, unsigned int thoff)
{
struct tcphdr *tcph;
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);
return -1;
}
return 0;
}
static int nf_flow_nat_ip_tcp(struct sk_buff *skb, unsigned int thoff, static int nf_flow_nat_ip_tcp(struct sk_buff *skb, unsigned int thoff,
__be32 addr, __be32 new_addr) __be32 addr, __be32 new_addr)
{ {
@ -119,10 +136,9 @@ static int nf_flow_dnat_ip(const struct flow_offload *flow, struct sk_buff *skb,
} }
static int nf_flow_nat_ip(const struct flow_offload *flow, struct sk_buff *skb, static int nf_flow_nat_ip(const struct flow_offload *flow, struct sk_buff *skb,
enum flow_offload_tuple_dir dir) unsigned int thoff, enum flow_offload_tuple_dir dir)
{ {
struct iphdr *iph = ip_hdr(skb); struct iphdr *iph = ip_hdr(skb);
unsigned int thoff = iph->ihl * 4;
if (flow->flags & FLOW_OFFLOAD_SNAT && if (flow->flags & FLOW_OFFLOAD_SNAT &&
(nf_flow_snat_port(flow, skb, thoff, iph->protocol, dir) < 0 || (nf_flow_snat_port(flow, skb, thoff, iph->protocol, dir) < 0 ||
@ -202,6 +218,7 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
struct flow_offload *flow; struct flow_offload *flow;
struct net_device *outdev; struct net_device *outdev;
const struct rtable *rt; const struct rtable *rt;
unsigned int thoff;
struct iphdr *iph; struct iphdr *iph;
__be32 nexthop; __be32 nexthop;
@ -230,8 +247,12 @@ nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
if (skb_try_make_writable(skb, sizeof(*iph))) if (skb_try_make_writable(skb, sizeof(*iph)))
return NF_DROP; return NF_DROP;
thoff = ip_hdr(skb)->ihl * 4;
if (nf_flow_tcp_state_check(flow, skb, thoff))
return NF_ACCEPT;
if (flow->flags & (FLOW_OFFLOAD_SNAT | FLOW_OFFLOAD_DNAT) && if (flow->flags & (FLOW_OFFLOAD_SNAT | FLOW_OFFLOAD_DNAT) &&
nf_flow_nat_ip(flow, skb, dir) < 0) nf_flow_nat_ip(flow, skb, thoff, dir) < 0)
return NF_DROP; return NF_DROP;
flow->timeout = (u32)jiffies + NF_FLOW_TIMEOUT; flow->timeout = (u32)jiffies + NF_FLOW_TIMEOUT;
@ -439,6 +460,9 @@ nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
if (unlikely(nf_flow_exceeds_mtu(skb, flow->tuplehash[dir].tuple.mtu))) if (unlikely(nf_flow_exceeds_mtu(skb, flow->tuplehash[dir].tuple.mtu)))
return NF_ACCEPT; return NF_ACCEPT;
if (nf_flow_tcp_state_check(flow, skb, sizeof(*ip6h)))
return NF_ACCEPT;
if (skb_try_make_writable(skb, sizeof(*ip6h))) if (skb_try_make_writable(skb, sizeof(*ip6h)))
return NF_DROP; return NF_DROP;