--- /dev/null
+From: Pablo Neira Ayuso <pablo@netfilter.org>
+Date: Sun, 7 Jan 2018 01:04:19 +0100
+Subject: [PATCH] netfilter: flow table support for IPv6
+
+This patch adds the IPv6 flow table type, that implements the datapath
+flow table to forward IPv6 traffic.
+
+This patch exports ip6_dst_mtu_forward() that is required to check for
+mtu to pass up packets that need PMTUD handling to the classic
+forwarding path.
+
+Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
+---
+ create mode 100644 net/ipv6/netfilter/nf_flow_table_ipv6.c
+
+--- a/include/net/ipv6.h
++++ b/include/net/ipv6.h
+@@ -913,6 +913,8 @@ static inline struct sk_buff *ip6_finish
+ &inet6_sk(sk)->cork);
+ }
+
++unsigned int ip6_dst_mtu_forward(const struct dst_entry *dst);
++
+ int ip6_dst_lookup(struct net *net, struct sock *sk, struct dst_entry **dst,
+ struct flowi6 *fl6);
+ struct dst_entry *ip6_dst_lookup_flow(const struct sock *sk, struct flowi6 *fl6,
+--- a/net/ipv6/ip6_output.c
++++ b/net/ipv6/ip6_output.c
+@@ -370,7 +370,7 @@ static inline int ip6_forward_finish(str
+ return dst_output(net, sk, skb);
+ }
+
+-static unsigned int ip6_dst_mtu_forward(const struct dst_entry *dst)
++unsigned int ip6_dst_mtu_forward(const struct dst_entry *dst)
+ {
+ unsigned int mtu;
+ struct inet6_dev *idev;
+@@ -390,6 +390,7 @@ static unsigned int ip6_dst_mtu_forward(
+
+ return mtu;
+ }
++EXPORT_SYMBOL_GPL(ip6_dst_mtu_forward);
+
+ static bool ip6_pkt_too_big(const struct sk_buff *skb, unsigned int mtu)
+ {
+--- a/net/ipv6/netfilter/Kconfig
++++ b/net/ipv6/netfilter/Kconfig
+@@ -71,6 +71,14 @@ config NFT_FIB_IPV6
+ endif # NF_TABLES_IPV6
+ endif # NF_TABLES
+
++config NF_FLOW_TABLE_IPV6
++ select NF_FLOW_TABLE
++ tristate "Netfilter flow table IPv6 module"
++ help
++ This option adds the flow table IPv6 support.
++
++ To compile it as a module, choose M here.
++
+ config NF_DUP_IPV6
+ tristate "Netfilter IPv6 packet duplication to alternate destination"
+ depends on !NF_CONNTRACK || NF_CONNTRACK
+--- a/net/ipv6/netfilter/Makefile
++++ b/net/ipv6/netfilter/Makefile
+@@ -45,6 +45,9 @@ obj-$(CONFIG_NFT_REDIR_IPV6) += nft_redi
+ obj-$(CONFIG_NFT_DUP_IPV6) += nft_dup_ipv6.o
+ obj-$(CONFIG_NFT_FIB_IPV6) += nft_fib_ipv6.o
+
++# flow table support
++obj-$(CONFIG_NF_FLOW_TABLE_IPV6) += nf_flow_table_ipv6.o
++
+ # matches
+ obj-$(CONFIG_IP6_NF_MATCH_AH) += ip6t_ah.o
+ obj-$(CONFIG_IP6_NF_MATCH_EUI64) += ip6t_eui64.o
+--- /dev/null
++++ b/net/ipv6/netfilter/nf_flow_table_ipv6.c
+@@ -0,0 +1,277 @@
++#include <linux/kernel.h>
++#include <linux/init.h>
++#include <linux/module.h>
++#include <linux/netfilter.h>
++#include <linux/rhashtable.h>
++#include <linux/ipv6.h>
++#include <linux/netdevice.h>
++#include <linux/ipv6.h>
++#include <net/ipv6.h>
++#include <net/ip6_route.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_ipv6_tcp(struct sk_buff *skb, unsigned int thoff,
++ struct in6_addr *addr,
++ struct in6_addr *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_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)
++{
++ 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_replace16(&udph->check, skb, addr->s6_addr32,
++ new_addr->s6_addr32, true);
++ 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)
++{
++ switch (ip6h->nexthdr) {
++ case IPPROTO_TCP:
++ if (nf_flow_nat_ipv6_tcp(skb, thoff, addr, new_addr) < 0)
++ return NF_DROP;
++ break;
++ case IPPROTO_UDP:
++ if (nf_flow_nat_ipv6_udp(skb, thoff, addr, new_addr) < 0)
++ return NF_DROP;
++ 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)
++{
++ struct in6_addr addr, new_addr;
++
++ switch (dir) {
++ case FLOW_OFFLOAD_DIR_ORIGINAL:
++ addr = ip6h->saddr;
++ new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.dst_v6;
++ ip6h->saddr = new_addr;
++ break;
++ case FLOW_OFFLOAD_DIR_REPLY:
++ addr = ip6h->daddr;
++ new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.src_v6;
++ ip6h->daddr = new_addr;
++ break;
++ default:
++ return -1;
++ }
++
++ return 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)
++{
++ struct in6_addr addr, new_addr;
++
++ switch (dir) {
++ case FLOW_OFFLOAD_DIR_ORIGINAL:
++ addr = ip6h->daddr;
++ new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_REPLY].tuple.src_v6;
++ ip6h->daddr = new_addr;
++ break;
++ case FLOW_OFFLOAD_DIR_REPLY:
++ addr = ip6h->saddr;
++ new_addr = flow->tuplehash[FLOW_OFFLOAD_DIR_ORIGINAL].tuple.dst_v6;
++ ip6h->saddr = new_addr;
++ break;
++ default:
++ return -1;
++ }
++
++ return 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 = ipv6_hdr(skb);
++ unsigned int thoff = sizeof(*ip6h);
++
++ if (flow->flags & FLOW_OFFLOAD_SNAT &&
++ (nf_flow_snat_port(flow, skb, thoff, ip6h->nexthdr, dir) < 0 ||
++ nf_flow_snat_ipv6(flow, skb, ip6h, thoff, dir) < 0))
++ return -1;
++ if (flow->flags & FLOW_OFFLOAD_DNAT &&
++ (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;
++}
++
++static int nf_flow_tuple_ipv6(struct sk_buff *skb, const struct net_device *dev,
++ struct flow_offload_tuple *tuple)
++{
++ 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)
++ return -1;
++
++ thoff = sizeof(*ip6h);
++ if (!pskb_may_pull(skb, thoff + sizeof(*ports)))
++ return -1;
++
++ ports = (struct flow_ports *)(skb_network_header(skb) + thoff);
++
++ tuple->src_v6 = ip6h->saddr;
++ tuple->dst_v6 = ip6h->daddr;
++ tuple->src_port = ports->source;
++ tuple->dst_port = ports->dest;
++ tuple->l3proto = AF_INET6;
++ tuple->l4proto = ip6h->nexthdr;
++ 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 (skb_is_gso(skb) && skb_gso_validate_mtu(skb, mtu))
++ return false;
++
++ return true;
++}
++
++static bool nf_flow_exceeds_mtu(struct sk_buff *skb, const struct rt6_info *rt)
++{
++ u32 mtu;
++
++ mtu = ip6_dst_mtu_forward(&rt->dst);
++ if (__nf_flow_exceeds_mtu(skb, mtu))
++ return true;
++
++ return false;
++}
++
++static unsigned int
++nf_flow_offload_ipv6_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;
++ struct in6_addr *nexthop;
++ struct ipv6hdr *ip6h;
++ struct rt6_info *rt;
++
++ if (skb->protocol != htons(ETH_P_IPV6))
++ return NF_ACCEPT;
++
++ if (nf_flow_tuple_ipv6(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 = (struct rt6_info *)flow->tuplehash[dir].tuple.dst_cache;
++ if (unlikely(nf_flow_exceeds_mtu(skb, rt)))
++ return NF_ACCEPT;
++
++ if (skb_try_make_writable(skb, sizeof(*ip6h)))
++ return NF_DROP;
++
++ if (flow->flags & (FLOW_OFFLOAD_SNAT | FLOW_OFFLOAD_DNAT) &&
++ nf_flow_nat_ipv6(flow, skb, dir) < 0)
++ return NF_DROP;
++
++ flow->timeout = (u32)jiffies + NF_FLOW_TIMEOUT;
++ ip6h = ipv6_hdr(skb);
++ ip6h->hop_limit--;
++
++ skb->dev = outdev;
++ nexthop = rt6_nexthop(rt, &flow->tuplehash[!dir].tuple.src_v6);
++ neigh_xmit(NEIGH_ND_TABLE, outdev, nexthop, skb);
++
++ return NF_STOLEN;
++}
++
++static struct nf_flowtable_type flowtable_ipv6 = {
++ .family = NFPROTO_IPV6,
++ .params = &nf_flow_offload_rhash_params,
++ .gc = nf_flow_offload_work_gc,
++ .hook = nf_flow_offload_ipv6_hook,
++ .owner = THIS_MODULE,
++};
++
++static int __init nf_flow_ipv6_module_init(void)
++{
++ nft_register_flowtable_type(&flowtable_ipv6);
++
++ return 0;
++}
++
++static void __exit nf_flow_ipv6_module_exit(void)
++{
++ nft_unregister_flowtable_type(&flowtable_ipv6);
++}
++
++module_init(nf_flow_ipv6_module_init);
++module_exit(nf_flow_ipv6_module_exit);
++
++MODULE_LICENSE("GPL");
++MODULE_AUTHOR("Pablo Neira Ayuso <pablo@netfilter.org>");
++MODULE_ALIAS_NF_FLOWTABLE(AF_INET6);
projects / openwrt / openwrt.git / blobdiff