#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/netfilter.h>
#include <linux/rhashtable.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/netdevice.h>
#include <linux/if_ether.h>
#include <linux/if_vlan.h>
#include <net/gre.h>
#include <net/gso.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <net/ip6_route.h>
#include <net/ip6_tunnel.h>
#include <net/neighbour.h>
#include <net/netfilter/nf_flow_table.h>
#include <net/netfilter/nf_conntrack_acct.h>
#include <linux/tcp.h>
#include <linux/udp.h>
static int nf_flow_state_check(struct flow_offload *flow, int proto,
struct sk_buff *skb, unsigned int thoff)
{
struct tcphdr *tcph;
if (proto != IPPROTO_TCP)
return 0;
tcph = (void *)(skb_network_header(skb) + thoff);
if (tcph->syn && test_bit(NF_FLOW_CLOSING, &flow->flags)) {
flow_offload_teardown(flow);
return -1;
}
if ((tcph->fin || tcph->rst) &&
!test_bit(NF_FLOW_CLOSING, &flow->flags))
set_bit(NF_FLOW_CLOSING, &flow->flags);
return 0;
}
static void nf_flow_nat_ip_tcp(struct sk_buff *skb, unsigned int thoff,
__be32 addr, __be32 new_addr)
{
struct tcphdr *tcph;
tcph = (void *)(skb_network_header(skb) + thoff);
inet_proto_csum_replace4(&tcph->check, skb, addr, new_addr, true);
}
static void nf_flow_nat_ip_udp(struct sk_buff *skb, unsigned int thoff,
__be32 addr, __be32 new_addr)
{
struct udphdr *udph;
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;
}
}
static void 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:
nf_flow_nat_ip_tcp(skb, thoff, addr, new_addr);
break;
case IPPROTO_UDP:
nf_flow_nat_ip_udp(skb, thoff, addr, new_addr);
break;
}
}
static void 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;
}
csum_replace4(&iph->check, addr, new_addr);
nf_flow_nat_ip_l4proto(skb, iph, thoff, addr, new_addr);
}
static void 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;
}
csum_replace4(&iph->check, addr, new_addr);
nf_flow_nat_ip_l4proto(skb, iph, thoff, addr, new_addr);
}
static void nf_flow_nat_ip(const struct flow_offload *flow, struct sk_buff *skb,
unsigned int thoff, enum flow_offload_tuple_dir dir,
struct iphdr *iph)
{
if (test_bit(NF_FLOW_SNAT, &flow->flags)) {
nf_flow_snat_port(flow, skb, thoff, iph->protocol, dir);
nf_flow_snat_ip(flow, skb, iph, thoff, dir);
}
if (test_bit(NF_FLOW_DNAT, &flow->flags)) {
nf_flow_dnat_port(flow, skb, thoff, iph->protocol, dir);
nf_flow_dnat_ip(flow, skb, iph, thoff, dir);
}
}
static bool ip_has_options(unsigned int thoff)
{
return thoff != sizeof(struct iphdr);
}
struct nf_flowtable_ctx {
const struct net_device *in;
u32 offset;
u32 hdrsize;
struct {
u32 hdr_size;
u8 proto;
} tun;
};
static void nf_flow_tuple_encap(struct nf_flowtable_ctx *ctx,
struct sk_buff *skb,
struct flow_offload_tuple *tuple)
{
__be16 inner_proto = skb->protocol;
struct vlan_ethhdr *veth;
struct pppoe_hdr *phdr;
struct ipv6hdr *ip6h;
struct iphdr *iph;
u16 offset = 0;
int i = 0;
if (skb_vlan_tag_present(skb)) {
tuple->encap[i].id = skb_vlan_tag_get(skb);
tuple->encap[i].proto = skb->vlan_proto;
i++;
}
switch (skb->protocol) {
case htons(ETH_P_8021Q):
veth = (struct vlan_ethhdr *)skb_mac_header(skb);
tuple->encap[i].id = ntohs(veth->h_vlan_TCI);
tuple->encap[i].proto = skb->protocol;
inner_proto = veth->h_vlan_encapsulated_proto;
offset += VLAN_HLEN;
break;
case htons(ETH_P_PPP_SES):
phdr = (struct pppoe_hdr *)skb_network_header(skb);
tuple->encap[i].id = ntohs(phdr->sid);
tuple->encap[i].proto = skb->protocol;
inner_proto = *((__be16 *)(phdr + 1));
offset += PPPOE_SES_HLEN;
break;
}
switch (inner_proto) {
case htons(ETH_P_IP):
iph = (struct iphdr *)(skb_network_header(skb) + offset);
if (ctx->tun.proto == IPPROTO_IPIP) {
tuple->tun.dst_v4.s_addr = iph->daddr;
tuple->tun.src_v4.s_addr = iph->saddr;
tuple->tun.l3_proto = IPPROTO_IPIP;
}
break;
case htons(ETH_P_IPV6):
ip6h = (struct ipv6hdr *)(skb_network_header(skb) + offset);
if (ctx->tun.proto == IPPROTO_IPV6) {
tuple->tun.dst_v6 = ip6h->daddr;
tuple->tun.src_v6 = ip6h->saddr;
tuple->tun.l3_proto = IPPROTO_IPV6;
}
break;
default:
break;
}
}
static int nf_flow_tuple_ip(struct nf_flowtable_ctx *ctx, struct sk_buff *skb,
struct flow_offload_tuple *tuple)
{
struct flow_ports *ports;
unsigned int thoff;
struct iphdr *iph;
u8 ipproto;
if (!pskb_may_pull(skb, sizeof(*iph) + ctx->offset))
return -1;
iph = (struct iphdr *)(skb_network_header(skb) + ctx->offset);
thoff = (iph->ihl * 4);
if (ip_is_fragment(iph) ||
unlikely(ip_has_options(thoff)))
return -1;
thoff += ctx->offset;
ipproto = iph->protocol;
switch (ipproto) {
case IPPROTO_TCP:
ctx->hdrsize = sizeof(struct tcphdr);
break;
case IPPROTO_UDP:
ctx->hdrsize = sizeof(struct udphdr);
break;
#ifdef CONFIG_NF_CT_PROTO_GRE
case IPPROTO_GRE:
ctx->hdrsize = sizeof(struct gre_base_hdr);
break;
#endif
default:
return -1;
}
if (iph->ttl <= 1)
return -1;
if (!pskb_may_pull(skb, thoff + ctx->hdrsize))
return -1;
switch (ipproto) {
case IPPROTO_TCP:
case IPPROTO_UDP:
ports = (struct flow_ports *)(skb_network_header(skb) + thoff);
tuple->src_port = ports->source;
tuple->dst_port = ports->dest;
break;
case IPPROTO_GRE: {
struct gre_base_hdr *greh;
greh = (struct gre_base_hdr *)(skb_network_header(skb) + thoff);
if ((greh->flags & GRE_VERSION) != GRE_VERSION_0)
return -1;
break;
}
}
iph = (struct iphdr *)(skb_network_header(skb) + ctx->offset);
tuple->src_v4.s_addr = iph->saddr;
tuple->dst_v4.s_addr = iph->daddr;
tuple->l3proto = AF_INET;
tuple->l4proto = ipproto;
tuple->iifidx = ctx->in->ifindex;
nf_flow_tuple_encap(ctx, skb, tuple);
return 0;
}
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_network_len(skb, mtu))
return false;
return true;
}
static inline bool nf_flow_dst_check(struct flow_offload_tuple *tuple)
{
if (tuple->xmit_type != FLOW_OFFLOAD_XMIT_NEIGH &&
tuple->xmit_type != FLOW_OFFLOAD_XMIT_XFRM)
return true;
return dst_check(tuple->dst_cache, tuple->dst_cookie);
}
static unsigned int nf_flow_xmit_xfrm(struct sk_buff *skb,
const struct nf_hook_state *state,
struct dst_entry *dst)
{
skb_orphan(skb);
skb_dst_set_noref(skb, dst);
dst_output(state->net, state->sk, skb);
return NF_STOLEN;
}
static bool nf_flow_ip4_tunnel_proto(struct nf_flowtable_ctx *ctx,
struct sk_buff *skb)
{
struct iphdr *iph;
u16 size;
if (!pskb_may_pull(skb, sizeof(*iph) + ctx->offset))
return false;
iph = (struct iphdr *)(skb_network_header(skb) + ctx->offset);
size = iph->ihl << 2;
if (ip_is_fragment(iph) || unlikely(ip_has_options(size)))
return false;
if (iph->ttl <= 1)
return false;
if (iph->protocol == IPPROTO_IPIP) {
ctx->tun.proto = IPPROTO_IPIP;
ctx->tun.hdr_size = size;
ctx->offset += size;
}
return true;
}
static bool nf_flow_ip6_tunnel_proto(struct nf_flowtable_ctx *ctx,
struct sk_buff *skb)
{
#if IS_ENABLED(CONFIG_IPV6)
struct ipv6hdr *ip6h, _ip6h;
__be16 frag_off;
u8 nexthdr;
int hdrlen;
ip6h = skb_header_pointer(skb, ctx->offset, sizeof(*ip6h), &_ip6h);
if (!ip6h)
return false;
if (ip6h->hop_limit <= 1)
return false;
nexthdr = ip6h->nexthdr;
hdrlen = ipv6_skip_exthdr(skb, sizeof(*ip6h) + ctx->offset, &nexthdr,
&frag_off);
if (hdrlen < 0)
return false;
if (nexthdr == IPPROTO_IPV6) {
ctx->tun.hdr_size = hdrlen;
ctx->tun.proto = IPPROTO_IPV6;
}
ctx->offset += ctx->tun.hdr_size;
return true;
#else
return false;
#endif
}
static void nf_flow_ip_tunnel_pop(struct nf_flowtable_ctx *ctx,
struct sk_buff *skb)
{
if (ctx->tun.proto != IPPROTO_IPIP &&
ctx->tun.proto != IPPROTO_IPV6)
return;
skb_pull(skb, ctx->tun.hdr_size);
skb_reset_network_header(skb);
}
static bool nf_flow_skb_encap_protocol(struct nf_flowtable_ctx *ctx,
struct sk_buff *skb, __be16 proto)
{
__be16 inner_proto = skb->protocol;
struct vlan_ethhdr *veth;
bool ret = false;
switch (skb->protocol) {
case htons(ETH_P_8021Q):
if (!pskb_may_pull(skb, skb_mac_offset(skb) + sizeof(*veth)))
return false;
veth = (struct vlan_ethhdr *)skb_mac_header(skb);
if (veth->h_vlan_encapsulated_proto == proto) {
ctx->offset += VLAN_HLEN;
inner_proto = proto;
ret = true;
}
break;
case htons(ETH_P_PPP_SES):
if (nf_flow_pppoe_proto(skb, &inner_proto) &&
inner_proto == proto) {
ctx->offset += PPPOE_SES_HLEN;
ret = true;
}
break;
}
switch (inner_proto) {
case htons(ETH_P_IP):
ret = nf_flow_ip4_tunnel_proto(ctx, skb);
break;
case htons(ETH_P_IPV6):
ret = nf_flow_ip6_tunnel_proto(ctx, skb);
break;
default:
break;
}
return ret;
}
static void nf_flow_encap_pop(struct nf_flowtable_ctx *ctx,
struct sk_buff *skb,
struct flow_offload_tuple_rhash *tuplehash)
{
struct vlan_hdr *vlan_hdr;
int i;
for (i = 0; i < tuplehash->tuple.encap_num; i++) {
if (skb_vlan_tag_present(skb)) {
__vlan_hwaccel_clear_tag(skb);
continue;
}
switch (skb->protocol) {
case htons(ETH_P_8021Q):
vlan_hdr = (struct vlan_hdr *)skb->data;
__skb_pull(skb, VLAN_HLEN);
vlan_set_encap_proto(skb, vlan_hdr);
skb_reset_network_header(skb);
break;
case htons(ETH_P_PPP_SES):
skb->protocol = __nf_flow_pppoe_proto(skb);
skb_pull(skb, PPPOE_SES_HLEN);
skb_reset_network_header(skb);
break;
}
}
if (skb->protocol == htons(ETH_P_IP) ||
skb->protocol == htons(ETH_P_IPV6))
nf_flow_ip_tunnel_pop(ctx, skb);
}
struct nf_flow_xmit {
const void *dest;
const void *source;
struct net_device *outdev;
};
static unsigned int nf_flow_queue_xmit(struct net *net, struct sk_buff *skb,
struct nf_flow_xmit *xmit)
{
skb->dev = xmit->outdev;
dev_hard_header(skb, skb->dev, ntohs(skb->protocol),
xmit->dest, xmit->source, skb->len);
dev_queue_xmit(skb);
return NF_STOLEN;
}
static struct flow_offload_tuple_rhash *
nf_flow_offload_lookup(struct nf_flowtable_ctx *ctx,
struct nf_flowtable *flow_table, struct sk_buff *skb)
{
struct flow_offload_tuple tuple = {};
if (!nf_flow_skb_encap_protocol(ctx, skb, htons(ETH_P_IP)))
return NULL;
if (nf_flow_tuple_ip(ctx, skb, &tuple) < 0)
return NULL;
return flow_offload_lookup(flow_table, &tuple);
}
static int nf_flow_offload_forward(struct nf_flowtable_ctx *ctx,
struct nf_flowtable *flow_table,
struct flow_offload_tuple_rhash *tuplehash,
struct sk_buff *skb)
{
enum flow_offload_tuple_dir dir;
struct flow_offload *flow;
unsigned int thoff, mtu;
struct iphdr *iph;
dir = tuplehash->tuple.dir;
flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
mtu = flow->tuplehash[dir].tuple.mtu + ctx->offset;
if (flow->tuplehash[!dir].tuple.tun_num)
mtu -= sizeof(*iph);
if (unlikely(nf_flow_exceeds_mtu(skb, mtu)))
return 0;
iph = (struct iphdr *)(skb_network_header(skb) + ctx->offset);
thoff = (iph->ihl * 4) + ctx->offset;
if (nf_flow_state_check(flow, iph->protocol, skb, thoff))
return 0;
if (!nf_flow_dst_check(&tuplehash->tuple)) {
flow_offload_teardown(flow);
return 0;
}
if (skb_try_make_writable(skb, thoff + ctx->hdrsize))
return -1;
flow_offload_refresh(flow_table, flow, false);
nf_flow_encap_pop(ctx, skb, tuplehash);
thoff -= ctx->offset;
iph = ip_hdr(skb);
nf_flow_nat_ip(flow, skb, thoff, dir, iph);
ip_decrease_ttl(iph);
skb_clear_tstamp(skb);
if (flow_table->flags & NF_FLOWTABLE_COUNTER)
nf_ct_acct_update(flow->ct, tuplehash->tuple.dir, skb->len);
return 1;
}
static int nf_flow_pppoe_push(struct sk_buff *skb, u16 id)
{
int data_len = skb->len + sizeof(__be16);
struct ppp_hdr {
struct pppoe_hdr hdr;
__be16 proto;
} *ph;
__be16 proto;
if (skb_cow_head(skb, PPPOE_SES_HLEN))
return -1;
switch (skb->protocol) {
case htons(ETH_P_IP):
proto = htons(PPP_IP);
break;
case htons(ETH_P_IPV6):
proto = htons(PPP_IPV6);
break;
default:
return -1;
}
__skb_push(skb, PPPOE_SES_HLEN);
skb_reset_network_header(skb);
ph = (struct ppp_hdr *)(skb->data);
ph->hdr.ver = 1;
ph->hdr.type = 1;
ph->hdr.code = 0;
ph->hdr.sid = htons(id);
ph->hdr.length = htons(data_len);
ph->proto = proto;
skb->protocol = htons(ETH_P_PPP_SES);
return 0;
}
static int nf_flow_tunnel_ipip_push(struct net *net, struct sk_buff *skb,
struct flow_offload_tuple *tuple,
__be32 *ip_daddr)
{
struct iphdr *iph = (struct iphdr *)skb_network_header(skb);
struct rtable *rt = dst_rtable(tuple->dst_cache);
u8 tos = iph->tos, ttl = iph->ttl;
__be16 frag_off = iph->frag_off;
u32 headroom = sizeof(*iph);
int err;
err = iptunnel_handle_offloads(skb, SKB_GSO_IPXIP4);
if (err)
return err;
skb_set_inner_ipproto(skb, IPPROTO_IPIP);
headroom += LL_RESERVED_SPACE(rt->dst.dev) + rt->dst.header_len;
err = skb_cow_head(skb, headroom);
if (err)
return err;
skb_scrub_packet(skb, true);
skb_clear_hash_if_not_l4(skb);
skb_push(skb, sizeof(*iph));
skb_reset_network_header(skb);
iph = ip_hdr(skb);
iph->version = 4;
iph->ihl = sizeof(*iph) >> 2;
iph->frag_off = ip_mtu_locked(&rt->dst) ? 0 : frag_off;
iph->protocol = tuple->tun.l3_proto;
iph->tos = tos;
iph->daddr = tuple->tun.src_v4.s_addr;
iph->saddr = tuple->tun.dst_v4.s_addr;
iph->ttl = ttl;
iph->tot_len = htons(skb->len);
__ip_select_ident(net, iph, skb_shinfo(skb)->gso_segs ?: 1);
ip_send_check(iph);
*ip_daddr = tuple->tun.src_v4.s_addr;
return 0;
}
static int nf_flow_tunnel_v4_push(struct net *net, struct sk_buff *skb,
struct flow_offload_tuple *tuple,
__be32 *ip_daddr)
{
if (tuple->tun_num)
return nf_flow_tunnel_ipip_push(net, skb, tuple, ip_daddr);
return 0;
}
struct ipv6_tel_txoption {
struct ipv6_txoptions ops;
__u8 dst_opt[8];
};
static int nf_flow_tunnel_ip6ip6_push(struct net *net, struct sk_buff *skb,
struct flow_offload_tuple *tuple,
struct in6_addr **ip6_daddr,
int encap_limit)
{
struct ipv6hdr *ip6h = (struct ipv6hdr *)skb_network_header(skb);
u8 hop_limit = ip6h->hop_limit, proto = IPPROTO_IPV6;
struct rtable *rt = dst_rtable(tuple->dst_cache);
__u8 dsfield = ipv6_get_dsfield(ip6h);
struct flowi6 fl6 = {
.daddr = tuple->tun.src_v6,
.saddr = tuple->tun.dst_v6,
.flowi6_proto = proto,
};
int err, mtu;
u32 headroom;
err = iptunnel_handle_offloads(skb, SKB_GSO_IPXIP6);
if (err)
return err;
skb_set_inner_ipproto(skb, proto);
headroom = sizeof(*ip6h) + LL_RESERVED_SPACE(rt->dst.dev) +
rt->dst.header_len;
if (encap_limit)
headroom += 8;
err = skb_cow_head(skb, headroom);
if (err)
return err;
skb_scrub_packet(skb, true);
mtu = dst_mtu(&rt->dst) - sizeof(*ip6h);
if (encap_limit)
mtu -= 8;
mtu = max(mtu, IPV6_MIN_MTU);
skb_dst_update_pmtu_no_confirm(skb, mtu);
if (encap_limit > 0) {
struct ipv6_tel_txoption opt = {
.dst_opt[2] = IPV6_TLV_TNL_ENCAP_LIMIT,
.dst_opt[3] = 1,
.dst_opt[4] = encap_limit,
.dst_opt[5] = IPV6_TLV_PADN,
.dst_opt[6] = 1,
};
struct ipv6_opt_hdr *hopt;
opt.ops.dst1opt = (struct ipv6_opt_hdr *)opt.dst_opt;
opt.ops.opt_nflen = 8;
hopt = skb_push(skb, ipv6_optlen(opt.ops.dst1opt));
memcpy(hopt, opt.ops.dst1opt, ipv6_optlen(opt.ops.dst1opt));
hopt->nexthdr = IPPROTO_IPV6;
proto = NEXTHDR_DEST;
}
skb_push(skb, sizeof(*ip6h));
skb_reset_network_header(skb);
ip6h = ipv6_hdr(skb);
ip6_flow_hdr(ip6h, dsfield,
ip6_make_flowlabel(net, skb, fl6.flowlabel, true, &fl6));
ip6h->hop_limit = hop_limit;
ip6h->nexthdr = proto;
ip6h->daddr = tuple->tun.src_v6;
ip6h->saddr = tuple->tun.dst_v6;
ipv6_hdr(skb)->payload_len = htons(skb->len - sizeof(*ip6h));
IP6CB(skb)->nhoff = offsetof(struct ipv6hdr, nexthdr);
*ip6_daddr = &tuple->tun.src_v6;
return 0;
}
static int nf_flow_tunnel_v6_push(struct net *net, struct sk_buff *skb,
struct flow_offload_tuple *tuple,
struct in6_addr **ip6_daddr,
int encap_limit)
{
if (tuple->tun_num)
return nf_flow_tunnel_ip6ip6_push(net, skb, tuple, ip6_daddr,
encap_limit);
return 0;
}
static int nf_flow_encap_push(struct sk_buff *skb,
struct flow_offload_tuple *tuple)
{
int i;
for (i = 0; i < tuple->encap_num; i++) {
switch (tuple->encap[i].proto) {
case htons(ETH_P_8021Q):
case htons(ETH_P_8021AD):
skb_reset_mac_header(skb);
if (skb_vlan_push(skb, tuple->encap[i].proto,
tuple->encap[i].id) < 0)
return -1;
break;
case htons(ETH_P_PPP_SES):
if (nf_flow_pppoe_push(skb, tuple->encap[i].id) < 0)
return -1;
break;
}
}
return 0;
}
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 *other_tuple;
enum flow_offload_tuple_dir dir;
struct nf_flowtable_ctx ctx = {
.in = state->in,
};
struct nf_flow_xmit xmit = {};
struct flow_offload *flow;
struct neighbour *neigh;
struct rtable *rt;
__be32 ip_daddr;
int ret;
tuplehash = nf_flow_offload_lookup(&ctx, flow_table, skb);
if (!tuplehash)
return NF_ACCEPT;
ret = nf_flow_offload_forward(&ctx, flow_table, tuplehash, skb);
if (ret < 0)
return NF_DROP;
else if (ret == 0)
return NF_ACCEPT;
if (unlikely(tuplehash->tuple.xmit_type == FLOW_OFFLOAD_XMIT_XFRM)) {
rt = dst_rtable(tuplehash->tuple.dst_cache);
memset(skb->cb, 0, sizeof(struct inet_skb_parm));
IPCB(skb)->iif = skb->dev->ifindex;
IPCB(skb)->flags = IPSKB_FORWARDED;
return nf_flow_xmit_xfrm(skb, state, &rt->dst);
}
dir = tuplehash->tuple.dir;
flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
other_tuple = &flow->tuplehash[!dir].tuple;
ip_daddr = other_tuple->src_v4.s_addr;
if (nf_flow_tunnel_v4_push(state->net, skb, other_tuple, &ip_daddr) < 0)
return NF_DROP;
if (nf_flow_encap_push(skb, other_tuple) < 0)
return NF_DROP;
switch (tuplehash->tuple.xmit_type) {
case FLOW_OFFLOAD_XMIT_NEIGH:
rt = dst_rtable(tuplehash->tuple.dst_cache);
xmit.outdev = dev_get_by_index_rcu(state->net, tuplehash->tuple.ifidx);
if (!xmit.outdev) {
flow_offload_teardown(flow);
return NF_DROP;
}
neigh = ip_neigh_gw4(rt->dst.dev, rt_nexthop(rt, ip_daddr));
if (IS_ERR(neigh)) {
flow_offload_teardown(flow);
return NF_DROP;
}
xmit.dest = neigh->ha;
skb_dst_set_noref(skb, &rt->dst);
break;
case FLOW_OFFLOAD_XMIT_DIRECT:
xmit.outdev = dev_get_by_index_rcu(state->net, tuplehash->tuple.out.ifidx);
if (!xmit.outdev) {
flow_offload_teardown(flow);
return NF_DROP;
}
xmit.dest = tuplehash->tuple.out.h_dest;
xmit.source = tuplehash->tuple.out.h_source;
break;
default:
WARN_ON_ONCE(1);
return NF_DROP;
}
return nf_flow_queue_xmit(state->net, skb, &xmit);
}
EXPORT_SYMBOL_GPL(nf_flow_offload_ip_hook);
static void nf_flow_nat_ipv6_tcp(struct sk_buff *skb, unsigned int thoff,
struct in6_addr *addr,
struct in6_addr *new_addr,
struct ipv6hdr *ip6h)
{
struct tcphdr *tcph;
tcph = (void *)(skb_network_header(skb) + thoff);
inet_proto_csum_replace16(&tcph->check, skb, addr->s6_addr32,
new_addr->s6_addr32, true);
}
static void nf_flow_nat_ipv6_udp(struct sk_buff *skb, unsigned int thoff,
struct in6_addr *addr,
struct in6_addr *new_addr)
{
struct udphdr *udph;
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;
}
}
static void 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:
nf_flow_nat_ipv6_tcp(skb, thoff, addr, new_addr, ip6h);
break;
case IPPROTO_UDP:
nf_flow_nat_ipv6_udp(skb, thoff, addr, new_addr);
break;
}
}
static void 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;
}
nf_flow_nat_ipv6_l4proto(skb, ip6h, thoff, &addr, &new_addr);
}
static void 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;
}
nf_flow_nat_ipv6_l4proto(skb, ip6h, thoff, &addr, &new_addr);
}
static void nf_flow_nat_ipv6(const struct flow_offload *flow,
struct sk_buff *skb,
enum flow_offload_tuple_dir dir,
struct ipv6hdr *ip6h)
{
unsigned int thoff = sizeof(*ip6h);
if (test_bit(NF_FLOW_SNAT, &flow->flags)) {
nf_flow_snat_port(flow, skb, thoff, ip6h->nexthdr, dir);
nf_flow_snat_ipv6(flow, skb, ip6h, thoff, dir);
}
if (test_bit(NF_FLOW_DNAT, &flow->flags)) {
nf_flow_dnat_port(flow, skb, thoff, ip6h->nexthdr, dir);
nf_flow_dnat_ipv6(flow, skb, ip6h, thoff, dir);
}
}
static int nf_flow_tuple_ipv6(struct nf_flowtable_ctx *ctx, struct sk_buff *skb,
struct flow_offload_tuple *tuple)
{
struct flow_ports *ports;
struct ipv6hdr *ip6h;
unsigned int thoff;
u8 nexthdr;
thoff = sizeof(*ip6h) + ctx->offset;
if (!pskb_may_pull(skb, thoff))
return -1;
ip6h = (struct ipv6hdr *)(skb_network_header(skb) + ctx->offset);
nexthdr = ip6h->nexthdr;
switch (nexthdr) {
case IPPROTO_TCP:
ctx->hdrsize = sizeof(struct tcphdr);
break;
case IPPROTO_UDP:
ctx->hdrsize = sizeof(struct udphdr);
break;
#ifdef CONFIG_NF_CT_PROTO_GRE
case IPPROTO_GRE:
ctx->hdrsize = sizeof(struct gre_base_hdr);
break;
#endif
default:
return -1;
}
if (ip6h->hop_limit <= 1)
return -1;
if (!pskb_may_pull(skb, thoff + ctx->hdrsize))
return -1;
switch (nexthdr) {
case IPPROTO_TCP:
case IPPROTO_UDP:
ports = (struct flow_ports *)(skb_network_header(skb) + thoff);
tuple->src_port = ports->source;
tuple->dst_port = ports->dest;
break;
case IPPROTO_GRE: {
struct gre_base_hdr *greh;
greh = (struct gre_base_hdr *)(skb_network_header(skb) + thoff);
if ((greh->flags & GRE_VERSION) != GRE_VERSION_0)
return -1;
break;
}
}
ip6h = (struct ipv6hdr *)(skb_network_header(skb) + ctx->offset);
tuple->src_v6 = ip6h->saddr;
tuple->dst_v6 = ip6h->daddr;
tuple->l3proto = AF_INET6;
tuple->l4proto = nexthdr;
tuple->iifidx = ctx->in->ifindex;
nf_flow_tuple_encap(ctx, skb, tuple);
return 0;
}
static int nf_flow_offload_ipv6_forward(struct nf_flowtable_ctx *ctx,
struct nf_flowtable *flow_table,
struct flow_offload_tuple_rhash *tuplehash,
struct sk_buff *skb, int encap_limit)
{
enum flow_offload_tuple_dir dir;
struct flow_offload *flow;
unsigned int thoff, mtu;
struct ipv6hdr *ip6h;
dir = tuplehash->tuple.dir;
flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
mtu = flow->tuplehash[dir].tuple.mtu + ctx->offset;
if (flow->tuplehash[!dir].tuple.tun_num) {
mtu -= sizeof(*ip6h);
if (encap_limit > 0)
mtu -= 8;
}
if (unlikely(nf_flow_exceeds_mtu(skb, mtu)))
return 0;
ip6h = (struct ipv6hdr *)(skb_network_header(skb) + ctx->offset);
thoff = sizeof(*ip6h) + ctx->offset;
if (nf_flow_state_check(flow, ip6h->nexthdr, skb, thoff))
return 0;
if (!nf_flow_dst_check(&tuplehash->tuple)) {
flow_offload_teardown(flow);
return 0;
}
if (skb_try_make_writable(skb, thoff + ctx->hdrsize))
return -1;
flow_offload_refresh(flow_table, flow, false);
nf_flow_encap_pop(ctx, skb, tuplehash);
ip6h = ipv6_hdr(skb);
nf_flow_nat_ipv6(flow, skb, dir, ip6h);
ip6h->hop_limit--;
skb_clear_tstamp(skb);
if (flow_table->flags & NF_FLOWTABLE_COUNTER)
nf_ct_acct_update(flow->ct, tuplehash->tuple.dir, skb->len);
return 1;
}
static struct flow_offload_tuple_rhash *
nf_flow_offload_ipv6_lookup(struct nf_flowtable_ctx *ctx,
struct nf_flowtable *flow_table,
struct sk_buff *skb)
{
struct flow_offload_tuple tuple = {};
if (!nf_flow_skb_encap_protocol(ctx, skb, htons(ETH_P_IPV6)))
return NULL;
if (nf_flow_tuple_ipv6(ctx, skb, &tuple) < 0)
return NULL;
return flow_offload_lookup(flow_table, &tuple);
}
unsigned int
nf_flow_offload_ipv6_hook(void *priv, struct sk_buff *skb,
const struct nf_hook_state *state)
{
int encap_limit = IPV6_DEFAULT_TNL_ENCAP_LIMIT;
struct flow_offload_tuple_rhash *tuplehash;
struct nf_flowtable *flow_table = priv;
struct flow_offload_tuple *other_tuple;
enum flow_offload_tuple_dir dir;
struct nf_flowtable_ctx ctx = {
.in = state->in,
};
struct nf_flow_xmit xmit = {};
struct in6_addr *ip6_daddr;
struct flow_offload *flow;
struct neighbour *neigh;
struct rt6_info *rt;
int ret;
tuplehash = nf_flow_offload_ipv6_lookup(&ctx, flow_table, skb);
if (tuplehash == NULL)
return NF_ACCEPT;
ret = nf_flow_offload_ipv6_forward(&ctx, flow_table, tuplehash, skb,
encap_limit);
if (ret < 0)
return NF_DROP;
else if (ret == 0)
return NF_ACCEPT;
if (unlikely(tuplehash->tuple.xmit_type == FLOW_OFFLOAD_XMIT_XFRM)) {
rt = dst_rt6_info(tuplehash->tuple.dst_cache);
memset(skb->cb, 0, sizeof(struct inet6_skb_parm));
IP6CB(skb)->iif = skb->dev->ifindex;
IP6CB(skb)->flags = IP6SKB_FORWARDED;
return nf_flow_xmit_xfrm(skb, state, &rt->dst);
}
dir = tuplehash->tuple.dir;
flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
other_tuple = &flow->tuplehash[!dir].tuple;
ip6_daddr = &other_tuple->src_v6;
if (nf_flow_tunnel_v6_push(state->net, skb, other_tuple,
&ip6_daddr, encap_limit) < 0)
return NF_DROP;
if (nf_flow_encap_push(skb, other_tuple) < 0)
return NF_DROP;
switch (tuplehash->tuple.xmit_type) {
case FLOW_OFFLOAD_XMIT_NEIGH:
rt = dst_rt6_info(tuplehash->tuple.dst_cache);
xmit.outdev = dev_get_by_index_rcu(state->net, tuplehash->tuple.ifidx);
if (!xmit.outdev) {
flow_offload_teardown(flow);
return NF_DROP;
}
neigh = ip_neigh_gw6(rt->dst.dev, rt6_nexthop(rt, ip6_daddr));
if (IS_ERR(neigh)) {
flow_offload_teardown(flow);
return NF_DROP;
}
xmit.dest = neigh->ha;
skb_dst_set_noref(skb, &rt->dst);
break;
case FLOW_OFFLOAD_XMIT_DIRECT:
xmit.outdev = dev_get_by_index_rcu(state->net, tuplehash->tuple.out.ifidx);
if (!xmit.outdev) {
flow_offload_teardown(flow);
return NF_DROP;
}
xmit.dest = tuplehash->tuple.out.h_dest;
xmit.source = tuplehash->tuple.out.h_source;
break;
default:
WARN_ON_ONCE(1);
return NF_DROP;
}
return nf_flow_queue_xmit(state->net, skb, &xmit);
}
EXPORT_SYMBOL_GPL(nf_flow_offload_ipv6_hook);
