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82 lines
2.3 KiB
82 lines
2.3 KiB
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7 years ago
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From: Felix Fietkau <nbd@nbd.name>
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Date: Sun, 25 Feb 2018 15:42:58 +0100
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Subject: [PATCH] netfilter: nf_flow_table: tear down TCP flows if RST or
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FIN was seen
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Allow the slow path to handle the shutdown of the connection with proper
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timeouts
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Signed-off-by: Felix Fietkau <nbd@nbd.name>
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---
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--- a/net/netfilter/nf_flow_table_ip.c
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+++ b/net/netfilter/nf_flow_table_ip.c
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@@ -15,6 +15,23 @@
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#include <linux/tcp.h>
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#include <linux/udp.h>
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+static int nf_flow_tcp_state_check(struct flow_offload *flow,
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+ struct sk_buff *skb, unsigned int thoff)
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+{
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+ struct tcphdr *tcph;
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+
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+ if (!pskb_may_pull(skb, thoff + sizeof(*tcph)))
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+ return -1;
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+
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+ tcph = (void *)(skb_network_header(skb) + thoff);
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+ if (unlikely(tcph->fin || tcph->rst)) {
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+ flow_offload_teardown(flow);
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+ return -1;
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+ }
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+
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+ return 0;
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+}
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+
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static int nf_flow_nat_ip_tcp(struct sk_buff *skb, unsigned int thoff,
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__be32 addr, __be32 new_addr)
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{
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@@ -118,10 +135,9 @@ static int nf_flow_dnat_ip(const struct
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}
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static int nf_flow_nat_ip(const struct flow_offload *flow, struct sk_buff *skb,
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- enum flow_offload_tuple_dir dir)
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+ unsigned int thoff, enum flow_offload_tuple_dir dir)
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{
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struct iphdr *iph = ip_hdr(skb);
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- unsigned int thoff = iph->ihl * 4;
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if (flow->flags & FLOW_OFFLOAD_SNAT &&
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(nf_flow_snat_port(flow, skb, thoff, iph->protocol, dir) < 0 ||
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@@ -201,6 +217,7 @@ nf_flow_offload_ip_hook(void *priv, stru
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struct flow_offload *flow;
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struct net_device *outdev;
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const struct rtable *rt;
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+ unsigned int thoff;
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struct iphdr *iph;
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__be32 nexthop;
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@@ -229,8 +246,12 @@ nf_flow_offload_ip_hook(void *priv, stru
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if (skb_try_make_writable(skb, sizeof(*iph)))
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return NF_DROP;
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+ thoff = ip_hdr(skb)->ihl * 4;
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+ if (nf_flow_tcp_state_check(flow, skb, thoff))
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+ return NF_ACCEPT;
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+
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if (flow->flags & (FLOW_OFFLOAD_SNAT | FLOW_OFFLOAD_DNAT) &&
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- nf_flow_nat_ip(flow, skb, dir) < 0)
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+ nf_flow_nat_ip(flow, skb, thoff, dir) < 0)
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return NF_DROP;
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flow->timeout = (u32)jiffies + NF_FLOW_TIMEOUT;
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@@ -438,6 +459,9 @@ nf_flow_offload_ipv6_hook(void *priv, st
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if (unlikely(nf_flow_exceeds_mtu(skb, flow->tuplehash[dir].tuple.mtu)))
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return NF_ACCEPT;
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+ if (nf_flow_tcp_state_check(flow, skb, sizeof(*ip6h)))
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+ return NF_ACCEPT;
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+
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if (skb_try_make_writable(skb, sizeof(*ip6h)))
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return NF_DROP;
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