netfilter: nf_flow_table: move ipv4 offload hook code to nf_flow_table

Allows some minor code sharing with the ipv6 hook code and is also
useful as preparation for adding iptables support for offload

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 0 insertions, 241 deletions

diff --git a/net/ipv4/netfilter/nf_flow_table_ipv4.c b/net/ipv4/netfilter/nf_flow_table_ipv4.c
index 461b1815e633..b6e43ff0c7b7 100644
--- a/net/ipv4/netfilter/nf_flow_table_ipv4.c
+++ b/net/ipv4/netfilter/nf_flow_table_ipv4.c
@@ -2,249 +2,8 @@
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/netfilter.h>
-#include <linux/rhashtable.h>
-#include <linux/ip.h>
-#include <linux/netdevice.h>
-#include <net/ip.h>
-#include <net/neighbour.h>
 #include <net/netfilter/nf_flow_table.h>
 #include <net/netfilter/nf_tables.h>
-/* For layer 4 checksum field offset. */
-#include <linux/tcp.h>
-#include <linux/udp.h>
-
-static int nf_flow_nat_ip_tcp(struct sk_buff *skb, unsigned int thoff,
-			      __be32 addr, __be32 new_addr)
-{
-	struct tcphdr *tcph;
-
-	if (!pskb_may_pull(skb, thoff + sizeof(*tcph)) ||
-	    skb_try_make_writable(skb, thoff + sizeof(*tcph)))
-		return -1;
-
-	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)
-{
-	struct udphdr *udph;
-
-	if (!pskb_may_pull(skb, thoff + sizeof(*udph)) ||
-	    skb_try_make_writable(skb, thoff + sizeof(*udph)))
-		return -1;
-
-	udph = (void *)(skb_network_header(skb) + thoff);
-	if (udph->check || skb->ip_summed == CHECKSUM_PARTIAL) {
-		inet_proto_csum_replace4(&udph->check, skb, addr,
-					 new_addr, true);
-		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)
-{
-	switch (iph->protocol) {
-	case IPPROTO_TCP:
-		if (nf_flow_nat_ip_tcp(skb, thoff, addr, new_addr) < 0)
-			return NF_DROP;
-		break;
-	case IPPROTO_UDP:
-		if (nf_flow_nat_ip_udp(skb, thoff, addr, new_addr) < 0)
-			return NF_DROP;
-		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)
-{
-	__be32 addr, new_addr;
-
-	switch (dir) {
-	case FLOW_OFFLOAD_DIR_ORIGINAL:
-		addr = iph->saddr;
-		new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_v4.s_addr;
-		iph->saddr = new_addr;
-		break;
-	case FLOW_OFFLOAD_DIR_REPLY:
-		addr = iph->daddr;
-		new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_v4.s_addr;
-		iph->daddr = new_addr;
-		break;
-	default:
-		return -1;
-	}
-	csum_replace4(&iph->check, addr, new_addr);
-
-	return 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)
-{
-	__be32 addr, new_addr;
-
-	switch (dir) {
-	case FLOW_OFFLOAD_DIR_ORIGINAL:
-		addr = iph->daddr;
-		new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_v4.s_addr;
-		iph->daddr = new_addr;
-		break;
-	case FLOW_OFFLOAD_DIR_REPLY:
-		addr = iph->saddr;
-		new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_v4.s_addr;
-		iph->saddr = new_addr;
-		break;
-	default:
-		return -1;
-	}
-	csum_replace4(&iph->check, addr, new_addr);
-
-	return 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,
-			  enum flow_offload_tuple_dir dir)
-{
-	struct iphdr *iph = ip_hdr(skb);
-	unsigned int thoff = iph->ihl * 4;
-
-	if (flow->flags & FLOW_OFFLOAD_SNAT &&
-	    (nf_flow_snat_port(flow, skb, thoff, iph->protocol, dir) < 0 ||
-	     nf_flow_snat_ip(flow, skb, iph, thoff, dir) < 0))
-		return -1;
-	if (flow->flags & FLOW_OFFLOAD_DNAT &&
-	    (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;
-}
-
-static bool ip_has_options(unsigned int thoff)
-{
-	return thoff != sizeof(struct iphdr);
-}
-
-static int nf_flow_tuple_ip(struct sk_buff *skb, const struct net_device *dev,
-			    struct flow_offload_tuple *tuple)
-{
-	struct flow_ports *ports;
-	unsigned int thoff;
-	struct iphdr *iph;
-
-	if (!pskb_may_pull(skb, sizeof(*iph)))
-		return -1;
-
-	iph = ip_hdr(skb);
-	thoff = iph->ihl * 4;
-
-	if (ip_is_fragment(iph) ||
-	    unlikely(ip_has_options(thoff)))
-		return -1;
-
-	if (iph->protocol != IPPROTO_TCP &&
-	    iph->protocol != IPPROTO_UDP)
-		return -1;
-
-	thoff = iph->ihl * 4;
-	if (!pskb_may_pull(skb, thoff + sizeof(*ports)))
-		return -1;
-
-	ports = (struct flow_ports *)(skb_network_header(skb) + thoff);
-
-	tuple->src_v4.s_addr	= iph->saddr;
-	tuple->dst_v4.s_addr	= iph->daddr;
-	tuple->src_port		= ports->source;
-	tuple->dst_port		= ports->dest;
-	tuple->l3proto		= AF_INET;
-	tuple->l4proto		= iph->protocol;
-	tuple->iifidx		= dev->ifindex;
-
-	return 0;
-}
-
-/* Based on ip_exceeds_mtu(). */
-static bool nf_flow_exceeds_mtu(const struct sk_buff *skb, unsigned int mtu)
-{
-	if (skb->len <= mtu)
-		return false;
-
-	if ((ip_hdr(skb)->frag_off & htons(IP_DF)) == 0)
-		return false;
-
-	if (skb_is_gso(skb) && skb_gso_validate_network_len(skb, mtu))
-		return false;
-
-	return true;
-}
-
-unsigned int
-nf_flow_offload_ip_hook(void *priv, struct sk_buff *skb,
-			const struct nf_hook_state *state)
-{
-	struct flow_offload_tuple_rhash *tuplehash;
-	struct nf_flowtable *flow_table = priv;
-	struct flow_offload_tuple tuple = {};
-	enum flow_offload_tuple_dir dir;
-	struct flow_offload *flow;
-	struct net_device *outdev;
-	const struct rtable *rt;
-	struct iphdr *iph;
-	__be32 nexthop;
-
-	if (skb->protocol != htons(ETH_P_IP))
-		return NF_ACCEPT;
-
-	if (nf_flow_tuple_ip(skb, state->in, &tuple) < 0)
-		return NF_ACCEPT;
-
-	tuplehash = flow_offload_lookup(flow_table, &tuple);
-	if (tuplehash == NULL)
-		return NF_ACCEPT;
-
-	outdev = dev_get_by_index_rcu(state->net, tuplehash->tuple.oifidx);
-	if (!outdev)
-		return NF_ACCEPT;
-
-	dir = tuplehash->tuple.dir;
-	flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
-	rt = (const struct rtable *)flow->tuplehash[dir].tuple.dst_cache;
-
-	if (unlikely(nf_flow_exceeds_mtu(skb, flow->tuplehash[dir].tuple.mtu)))
-		return NF_ACCEPT;
-
-	if (skb_try_make_writable(skb, sizeof(*iph)))
-		return NF_DROP;
-
-	if (flow->flags & (FLOW_OFFLOAD_SNAT | FLOW_OFFLOAD_DNAT) &&
-	    nf_flow_nat_ip(flow, skb, dir) < 0)
-		return NF_DROP;
-
-	flow->timeout = (u32)jiffies + NF_FLOW_TIMEOUT;
-	iph = ip_hdr(skb);
-	ip_decrease_ttl(iph);
-
-	skb->dev = outdev;
-	nexthop = rt_nexthop(rt, flow->tuplehash[!dir].tuple.src_v4.s_addr);
-	neigh_xmit(NEIGH_ARP_TABLE, outdev, &nexthop, skb);
-
-	return NF_STOLEN;
-}
-EXPORT_SYMBOL_GPL(nf_flow_offload_ip_hook);
 
 static struct nf_flowtable_type flowtable_ipv4 = {
 	.family		= NFPROTO_IPV4,