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act_ct.c
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act_ct.c
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// SPDX-License-Identifier: GPL-2.0 OR Linux-OpenIB
/* -
* net/sched/act_ct.c Connection Tracking action
*
* Authors: Paul Blakey <paulb@mellanox.com>
* Yossi Kuperman <yossiku@mellanox.com>
* Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/rtnetlink.h>
#include <linux/pkt_cls.h>
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/rhashtable.h>
#include <net/netlink.h>
#include <net/pkt_sched.h>
#include <net/pkt_cls.h>
#include <net/act_api.h>
#include <net/ip.h>
#include <net/ipv6_frag.h>
#include <uapi/linux/tc_act/tc_ct.h>
#include <net/tc_act/tc_ct.h>
#include <net/tc_wrapper.h>
#include <net/netfilter/nf_flow_table.h>
#include <net/netfilter/nf_conntrack.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_zones.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_acct.h>
#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
#include <net/netfilter/nf_conntrack_act_ct.h>
#include <net/netfilter/nf_conntrack_seqadj.h>
#include <uapi/linux/netfilter/nf_nat.h>
static struct workqueue_struct *act_ct_wq;
static struct rhashtable zones_ht;
static DEFINE_MUTEX(zones_mutex);
struct tcf_ct_flow_table {
struct rhash_head node; /* In zones tables */
struct rcu_work rwork;
struct nf_flowtable nf_ft;
refcount_t ref;
u16 zone;
bool dying;
};
static const struct rhashtable_params zones_params = {
.head_offset = offsetof(struct tcf_ct_flow_table, node),
.key_offset = offsetof(struct tcf_ct_flow_table, zone),
.key_len = sizeof_field(struct tcf_ct_flow_table, zone),
.automatic_shrinking = true,
};
static struct flow_action_entry *
tcf_ct_flow_table_flow_action_get_next(struct flow_action *flow_action)
{
int i = flow_action->num_entries++;
return &flow_action->entries[i];
}
static void tcf_ct_add_mangle_action(struct flow_action *action,
enum flow_action_mangle_base htype,
u32 offset,
u32 mask,
u32 val)
{
struct flow_action_entry *entry;
entry = tcf_ct_flow_table_flow_action_get_next(action);
entry->id = FLOW_ACTION_MANGLE;
entry->mangle.htype = htype;
entry->mangle.mask = ~mask;
entry->mangle.offset = offset;
entry->mangle.val = val;
}
/* The following nat helper functions check if the inverted reverse tuple
* (target) is different then the current dir tuple - meaning nat for ports
* and/or ip is needed, and add the relevant mangle actions.
*/
static void
tcf_ct_flow_table_add_action_nat_ipv4(const struct nf_conntrack_tuple *tuple,
struct nf_conntrack_tuple target,
struct flow_action *action)
{
if (memcmp(&target.src.u3, &tuple->src.u3, sizeof(target.src.u3)))
tcf_ct_add_mangle_action(action, FLOW_ACT_MANGLE_HDR_TYPE_IP4,
offsetof(struct iphdr, saddr),
0xFFFFFFFF,
be32_to_cpu(target.src.u3.ip));
if (memcmp(&target.dst.u3, &tuple->dst.u3, sizeof(target.dst.u3)))
tcf_ct_add_mangle_action(action, FLOW_ACT_MANGLE_HDR_TYPE_IP4,
offsetof(struct iphdr, daddr),
0xFFFFFFFF,
be32_to_cpu(target.dst.u3.ip));
}
static void
tcf_ct_add_ipv6_addr_mangle_action(struct flow_action *action,
union nf_inet_addr *addr,
u32 offset)
{
int i;
for (i = 0; i < sizeof(struct in6_addr) / sizeof(u32); i++)
tcf_ct_add_mangle_action(action, FLOW_ACT_MANGLE_HDR_TYPE_IP6,
i * sizeof(u32) + offset,
0xFFFFFFFF, be32_to_cpu(addr->ip6[i]));
}
static void
tcf_ct_flow_table_add_action_nat_ipv6(const struct nf_conntrack_tuple *tuple,
struct nf_conntrack_tuple target,
struct flow_action *action)
{
if (memcmp(&target.src.u3, &tuple->src.u3, sizeof(target.src.u3)))
tcf_ct_add_ipv6_addr_mangle_action(action, &target.src.u3,
offsetof(struct ipv6hdr,
saddr));
if (memcmp(&target.dst.u3, &tuple->dst.u3, sizeof(target.dst.u3)))
tcf_ct_add_ipv6_addr_mangle_action(action, &target.dst.u3,
offsetof(struct ipv6hdr,
daddr));
}
static void
tcf_ct_flow_table_add_action_nat_tcp(const struct nf_conntrack_tuple *tuple,
struct nf_conntrack_tuple target,
struct flow_action *action)
{
__be16 target_src = target.src.u.tcp.port;
__be16 target_dst = target.dst.u.tcp.port;
if (target_src != tuple->src.u.tcp.port)
tcf_ct_add_mangle_action(action, FLOW_ACT_MANGLE_HDR_TYPE_TCP,
offsetof(struct tcphdr, source),
0xFFFF, be16_to_cpu(target_src));
if (target_dst != tuple->dst.u.tcp.port)
tcf_ct_add_mangle_action(action, FLOW_ACT_MANGLE_HDR_TYPE_TCP,
offsetof(struct tcphdr, dest),
0xFFFF, be16_to_cpu(target_dst));
}
static void
tcf_ct_flow_table_add_action_nat_udp(const struct nf_conntrack_tuple *tuple,
struct nf_conntrack_tuple target,
struct flow_action *action)
{
__be16 target_src = target.src.u.udp.port;
__be16 target_dst = target.dst.u.udp.port;
if (target_src != tuple->src.u.udp.port)
tcf_ct_add_mangle_action(action, FLOW_ACT_MANGLE_HDR_TYPE_UDP,
offsetof(struct udphdr, source),
0xFFFF, be16_to_cpu(target_src));
if (target_dst != tuple->dst.u.udp.port)
tcf_ct_add_mangle_action(action, FLOW_ACT_MANGLE_HDR_TYPE_UDP,
offsetof(struct udphdr, dest),
0xFFFF, be16_to_cpu(target_dst));
}
static void tcf_ct_flow_table_add_action_meta(struct nf_conn *ct,
enum ip_conntrack_dir dir,
enum ip_conntrack_info ctinfo,
struct flow_action *action)
{
struct nf_conn_labels *ct_labels;
struct flow_action_entry *entry;
u32 *act_ct_labels;
entry = tcf_ct_flow_table_flow_action_get_next(action);
entry->id = FLOW_ACTION_CT_METADATA;
#if IS_ENABLED(CONFIG_NF_CONNTRACK_MARK)
entry->ct_metadata.mark = READ_ONCE(ct->mark);
#endif
/* aligns with the CT reference on the SKB nf_ct_set */
entry->ct_metadata.cookie = (unsigned long)ct | ctinfo;
entry->ct_metadata.orig_dir = dir == IP_CT_DIR_ORIGINAL;
act_ct_labels = entry->ct_metadata.labels;
ct_labels = nf_ct_labels_find(ct);
if (ct_labels)
memcpy(act_ct_labels, ct_labels->bits, NF_CT_LABELS_MAX_SIZE);
else
memset(act_ct_labels, 0, NF_CT_LABELS_MAX_SIZE);
}
static int tcf_ct_flow_table_add_action_nat(struct net *net,
struct nf_conn *ct,
enum ip_conntrack_dir dir,
struct flow_action *action)
{
const struct nf_conntrack_tuple *tuple = &ct->tuplehash[dir].tuple;
struct nf_conntrack_tuple target;
if (!(ct->status & IPS_NAT_MASK))
return 0;
nf_ct_invert_tuple(&target, &ct->tuplehash[!dir].tuple);
switch (tuple->src.l3num) {
case NFPROTO_IPV4:
tcf_ct_flow_table_add_action_nat_ipv4(tuple, target,
action);
break;
case NFPROTO_IPV6:
tcf_ct_flow_table_add_action_nat_ipv6(tuple, target,
action);
break;
default:
return -EOPNOTSUPP;
}
switch (nf_ct_protonum(ct)) {
case IPPROTO_TCP:
tcf_ct_flow_table_add_action_nat_tcp(tuple, target, action);
break;
case IPPROTO_UDP:
tcf_ct_flow_table_add_action_nat_udp(tuple, target, action);
break;
default:
return -EOPNOTSUPP;
}
return 0;
}
static int tcf_ct_flow_table_fill_actions(struct net *net,
struct flow_offload *flow,
enum flow_offload_tuple_dir tdir,
struct nf_flow_rule *flow_rule)
{
struct flow_action *action = &flow_rule->rule->action;
int num_entries = action->num_entries;
struct nf_conn *ct = flow->ct;
enum ip_conntrack_info ctinfo;
enum ip_conntrack_dir dir;
int i, err;
switch (tdir) {
case FLOW_OFFLOAD_DIR_ORIGINAL:
dir = IP_CT_DIR_ORIGINAL;
ctinfo = test_bit(IPS_SEEN_REPLY_BIT, &ct->status) ?
IP_CT_ESTABLISHED : IP_CT_NEW;
if (ctinfo == IP_CT_ESTABLISHED)
set_bit(NF_FLOW_HW_ESTABLISHED, &flow->flags);
break;
case FLOW_OFFLOAD_DIR_REPLY:
dir = IP_CT_DIR_REPLY;
ctinfo = IP_CT_ESTABLISHED_REPLY;
break;
default:
return -EOPNOTSUPP;
}
err = tcf_ct_flow_table_add_action_nat(net, ct, dir, action);
if (err)
goto err_nat;
tcf_ct_flow_table_add_action_meta(ct, dir, ctinfo, action);
return 0;
err_nat:
/* Clear filled actions */
for (i = num_entries; i < action->num_entries; i++)
memset(&action->entries[i], 0, sizeof(action->entries[i]));
action->num_entries = num_entries;
return err;
}
static struct nf_flowtable_type flowtable_ct = {
.action = tcf_ct_flow_table_fill_actions,
.owner = THIS_MODULE,
};
static int tcf_ct_flow_table_get(struct net *net, struct tcf_ct_params *params)
{
struct tcf_ct_flow_table *ct_ft;
int err = -ENOMEM;
mutex_lock(&zones_mutex);
ct_ft = rhashtable_lookup_fast(&zones_ht, ¶ms->zone, zones_params);
if (ct_ft && refcount_inc_not_zero(&ct_ft->ref))
goto out_unlock;
ct_ft = kzalloc(sizeof(*ct_ft), GFP_KERNEL);
if (!ct_ft)
goto err_alloc;
refcount_set(&ct_ft->ref, 1);
ct_ft->zone = params->zone;
err = rhashtable_insert_fast(&zones_ht, &ct_ft->node, zones_params);
if (err)
goto err_insert;
ct_ft->nf_ft.type = &flowtable_ct;
ct_ft->nf_ft.flags |= NF_FLOWTABLE_HW_OFFLOAD |
NF_FLOWTABLE_COUNTER;
err = nf_flow_table_init(&ct_ft->nf_ft);
if (err)
goto err_init;
write_pnet(&ct_ft->nf_ft.net, net);
__module_get(THIS_MODULE);
out_unlock:
params->ct_ft = ct_ft;
params->nf_ft = &ct_ft->nf_ft;
mutex_unlock(&zones_mutex);
return 0;
err_init:
rhashtable_remove_fast(&zones_ht, &ct_ft->node, zones_params);
err_insert:
kfree(ct_ft);
err_alloc:
mutex_unlock(&zones_mutex);
return err;
}
static void tcf_ct_flow_table_cleanup_work(struct work_struct *work)
{
struct flow_block_cb *block_cb, *tmp_cb;
struct tcf_ct_flow_table *ct_ft;
struct flow_block *block;
ct_ft = container_of(to_rcu_work(work), struct tcf_ct_flow_table,
rwork);
nf_flow_table_free(&ct_ft->nf_ft);
/* Remove any remaining callbacks before cleanup */
block = &ct_ft->nf_ft.flow_block;
down_write(&ct_ft->nf_ft.flow_block_lock);
list_for_each_entry_safe(block_cb, tmp_cb, &block->cb_list, list) {
list_del(&block_cb->list);
flow_block_cb_free(block_cb);
}
up_write(&ct_ft->nf_ft.flow_block_lock);
kfree(ct_ft);
module_put(THIS_MODULE);
}
static void tcf_ct_flow_table_put(struct tcf_ct_flow_table *ct_ft)
{
if (refcount_dec_and_test(&ct_ft->ref)) {
rhashtable_remove_fast(&zones_ht, &ct_ft->node, zones_params);
INIT_RCU_WORK(&ct_ft->rwork, tcf_ct_flow_table_cleanup_work);
queue_rcu_work(act_ct_wq, &ct_ft->rwork);
}
}
static void tcf_ct_flow_tc_ifidx(struct flow_offload *entry,
struct nf_conn_act_ct_ext *act_ct_ext, u8 dir)
{
entry->tuplehash[dir].tuple.xmit_type = FLOW_OFFLOAD_XMIT_TC;
entry->tuplehash[dir].tuple.tc.iifidx = act_ct_ext->ifindex[dir];
}
static void tcf_ct_flow_table_add(struct tcf_ct_flow_table *ct_ft,
struct nf_conn *ct,
bool tcp, bool bidirectional)
{
struct nf_conn_act_ct_ext *act_ct_ext;
struct flow_offload *entry;
int err;
if (test_and_set_bit(IPS_OFFLOAD_BIT, &ct->status))
return;
entry = flow_offload_alloc(ct);
if (!entry) {
WARN_ON_ONCE(1);
goto err_alloc;
}
if (tcp) {
ct->proto.tcp.seen[0].flags |= IP_CT_TCP_FLAG_BE_LIBERAL;
ct->proto.tcp.seen[1].flags |= IP_CT_TCP_FLAG_BE_LIBERAL;
}
if (bidirectional)
__set_bit(NF_FLOW_HW_BIDIRECTIONAL, &entry->flags);
act_ct_ext = nf_conn_act_ct_ext_find(ct);
if (act_ct_ext) {
tcf_ct_flow_tc_ifidx(entry, act_ct_ext, FLOW_OFFLOAD_DIR_ORIGINAL);
tcf_ct_flow_tc_ifidx(entry, act_ct_ext, FLOW_OFFLOAD_DIR_REPLY);
}
err = flow_offload_add(&ct_ft->nf_ft, entry);
if (err)
goto err_add;
return;
err_add:
flow_offload_free(entry);
err_alloc:
clear_bit(IPS_OFFLOAD_BIT, &ct->status);
}
static void tcf_ct_flow_table_process_conn(struct tcf_ct_flow_table *ct_ft,
struct nf_conn *ct,
enum ip_conntrack_info ctinfo)
{
bool tcp = false, bidirectional = true;
switch (nf_ct_protonum(ct)) {
case IPPROTO_TCP:
if ((ctinfo != IP_CT_ESTABLISHED &&
ctinfo != IP_CT_ESTABLISHED_REPLY) ||
!test_bit(IPS_ASSURED_BIT, &ct->status) ||
ct->proto.tcp.state != TCP_CONNTRACK_ESTABLISHED)
return;
tcp = true;
break;
case IPPROTO_UDP:
if (!nf_ct_is_confirmed(ct))
return;
if (!test_bit(IPS_ASSURED_BIT, &ct->status))
bidirectional = false;
break;
#ifdef CONFIG_NF_CT_PROTO_GRE
case IPPROTO_GRE: {
struct nf_conntrack_tuple *tuple;
if ((ctinfo != IP_CT_ESTABLISHED &&
ctinfo != IP_CT_ESTABLISHED_REPLY) ||
!test_bit(IPS_ASSURED_BIT, &ct->status) ||
ct->status & IPS_NAT_MASK)
return;
tuple = &ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple;
/* No support for GRE v1 */
if (tuple->src.u.gre.key || tuple->dst.u.gre.key)
return;
break;
}
#endif
default:
return;
}
if (nf_ct_ext_exist(ct, NF_CT_EXT_HELPER) ||
ct->status & IPS_SEQ_ADJUST)
return;
tcf_ct_flow_table_add(ct_ft, ct, tcp, bidirectional);
}
static bool
tcf_ct_flow_table_fill_tuple_ipv4(struct sk_buff *skb,
struct flow_offload_tuple *tuple,
struct tcphdr **tcph)
{
struct flow_ports *ports;
unsigned int thoff;
struct iphdr *iph;
size_t hdrsize;
u8 ipproto;
if (!pskb_network_may_pull(skb, sizeof(*iph)))
return false;
iph = ip_hdr(skb);
thoff = iph->ihl * 4;
if (ip_is_fragment(iph) ||
unlikely(thoff != sizeof(struct iphdr)))
return false;
ipproto = iph->protocol;
switch (ipproto) {
case IPPROTO_TCP:
hdrsize = sizeof(struct tcphdr);
break;
case IPPROTO_UDP:
hdrsize = sizeof(*ports);
break;
#ifdef CONFIG_NF_CT_PROTO_GRE
case IPPROTO_GRE:
hdrsize = sizeof(struct gre_base_hdr);
break;
#endif
default:
return false;
}
if (iph->ttl <= 1)
return false;
if (!pskb_network_may_pull(skb, thoff + hdrsize))
return false;
switch (ipproto) {
case IPPROTO_TCP:
*tcph = (void *)(skb_network_header(skb) + thoff);
fallthrough;
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 false;
break;
}
}
iph = ip_hdr(skb);
tuple->src_v4.s_addr = iph->saddr;
tuple->dst_v4.s_addr = iph->daddr;
tuple->l3proto = AF_INET;
tuple->l4proto = ipproto;
return true;
}
static bool
tcf_ct_flow_table_fill_tuple_ipv6(struct sk_buff *skb,
struct flow_offload_tuple *tuple,
struct tcphdr **tcph)
{
struct flow_ports *ports;
struct ipv6hdr *ip6h;
unsigned int thoff;
size_t hdrsize;
u8 nexthdr;
if (!pskb_network_may_pull(skb, sizeof(*ip6h)))
return false;
ip6h = ipv6_hdr(skb);
thoff = sizeof(*ip6h);
nexthdr = ip6h->nexthdr;
switch (nexthdr) {
case IPPROTO_TCP:
hdrsize = sizeof(struct tcphdr);
break;
case IPPROTO_UDP:
hdrsize = sizeof(*ports);
break;
#ifdef CONFIG_NF_CT_PROTO_GRE
case IPPROTO_GRE:
hdrsize = sizeof(struct gre_base_hdr);
break;
#endif
default:
return false;
}
if (ip6h->hop_limit <= 1)
return false;
if (!pskb_network_may_pull(skb, thoff + hdrsize))
return false;
switch (nexthdr) {
case IPPROTO_TCP:
*tcph = (void *)(skb_network_header(skb) + thoff);
fallthrough;
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 false;
break;
}
}
ip6h = ipv6_hdr(skb);
tuple->src_v6 = ip6h->saddr;
tuple->dst_v6 = ip6h->daddr;
tuple->l3proto = AF_INET6;
tuple->l4proto = nexthdr;
return true;
}
static bool tcf_ct_flow_table_lookup(struct tcf_ct_params *p,
struct sk_buff *skb,
u8 family)
{
struct nf_flowtable *nf_ft = &p->ct_ft->nf_ft;
struct flow_offload_tuple_rhash *tuplehash;
struct flow_offload_tuple tuple = {};
enum ip_conntrack_info ctinfo;
struct tcphdr *tcph = NULL;
struct flow_offload *flow;
struct nf_conn *ct;
u8 dir;
switch (family) {
case NFPROTO_IPV4:
if (!tcf_ct_flow_table_fill_tuple_ipv4(skb, &tuple, &tcph))
return false;
break;
case NFPROTO_IPV6:
if (!tcf_ct_flow_table_fill_tuple_ipv6(skb, &tuple, &tcph))
return false;
break;
default:
return false;
}
tuplehash = flow_offload_lookup(nf_ft, &tuple);
if (!tuplehash)
return false;
dir = tuplehash->tuple.dir;
flow = container_of(tuplehash, struct flow_offload, tuplehash[dir]);
ct = flow->ct;
if (dir == FLOW_OFFLOAD_DIR_REPLY &&
!test_bit(NF_FLOW_HW_BIDIRECTIONAL, &flow->flags)) {
/* Only offload reply direction after connection became
* assured.
*/
if (test_bit(IPS_ASSURED_BIT, &ct->status))
set_bit(NF_FLOW_HW_BIDIRECTIONAL, &flow->flags);
else if (test_bit(NF_FLOW_HW_ESTABLISHED, &flow->flags))
/* If flow_table flow has already been updated to the
* established state, then don't refresh.
*/
return false;
}
if (tcph && (unlikely(tcph->fin || tcph->rst))) {
flow_offload_teardown(flow);
return false;
}
if (dir == FLOW_OFFLOAD_DIR_ORIGINAL)
ctinfo = test_bit(IPS_SEEN_REPLY_BIT, &ct->status) ?
IP_CT_ESTABLISHED : IP_CT_NEW;
else
ctinfo = IP_CT_ESTABLISHED_REPLY;
flow_offload_refresh(nf_ft, flow);
nf_conntrack_get(&ct->ct_general);
nf_ct_set(skb, ct, ctinfo);
if (nf_ft->flags & NF_FLOWTABLE_COUNTER)
nf_ct_acct_update(ct, dir, skb->len);
return true;
}
static int tcf_ct_flow_tables_init(void)
{
return rhashtable_init(&zones_ht, &zones_params);
}
static void tcf_ct_flow_tables_uninit(void)
{
rhashtable_destroy(&zones_ht);
}
static struct tc_action_ops act_ct_ops;
struct tc_ct_action_net {
struct tc_action_net tn; /* Must be first */
bool labels;
};
/* Determine whether skb->_nfct is equal to the result of conntrack lookup. */
static bool tcf_ct_skb_nfct_cached(struct net *net, struct sk_buff *skb,
struct tcf_ct_params *p)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct;
ct = nf_ct_get(skb, &ctinfo);
if (!ct)
return false;
if (!net_eq(net, read_pnet(&ct->ct_net)))
goto drop_ct;
if (nf_ct_zone(ct)->id != p->zone)
goto drop_ct;
if (p->helper) {
struct nf_conn_help *help;
help = nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
if (help && rcu_access_pointer(help->helper) != p->helper)
goto drop_ct;
}
/* Force conntrack entry direction. */
if ((p->ct_action & TCA_CT_ACT_FORCE) &&
CTINFO2DIR(ctinfo) != IP_CT_DIR_ORIGINAL) {
if (nf_ct_is_confirmed(ct))
nf_ct_kill(ct);
goto drop_ct;
}
return true;
drop_ct:
nf_ct_put(ct);
nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
return false;
}
static u8 tcf_ct_skb_nf_family(struct sk_buff *skb)
{
u8 family = NFPROTO_UNSPEC;
switch (skb_protocol(skb, true)) {
case htons(ETH_P_IP):
family = NFPROTO_IPV4;
break;
case htons(ETH_P_IPV6):
family = NFPROTO_IPV6;
break;
default:
break;
}
return family;
}
static int tcf_ct_ipv4_is_fragment(struct sk_buff *skb, bool *frag)
{
unsigned int len;
len = skb_network_offset(skb) + sizeof(struct iphdr);
if (unlikely(skb->len < len))
return -EINVAL;
if (unlikely(!pskb_may_pull(skb, len)))
return -ENOMEM;
*frag = ip_is_fragment(ip_hdr(skb));
return 0;
}
static int tcf_ct_ipv6_is_fragment(struct sk_buff *skb, bool *frag)
{
unsigned int flags = 0, len, payload_ofs = 0;
unsigned short frag_off;
int nexthdr;
len = skb_network_offset(skb) + sizeof(struct ipv6hdr);
if (unlikely(skb->len < len))
return -EINVAL;
if (unlikely(!pskb_may_pull(skb, len)))
return -ENOMEM;
nexthdr = ipv6_find_hdr(skb, &payload_ofs, -1, &frag_off, &flags);
if (unlikely(nexthdr < 0))
return -EPROTO;
*frag = flags & IP6_FH_F_FRAG;
return 0;
}
static int tcf_ct_handle_fragments(struct net *net, struct sk_buff *skb,
u8 family, u16 zone, bool *defrag)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct;
int err = 0;
bool frag;
u8 proto;
u16 mru;
/* Previously seen (loopback)? Ignore. */
ct = nf_ct_get(skb, &ctinfo);
if ((ct && !nf_ct_is_template(ct)) || ctinfo == IP_CT_UNTRACKED)
return 0;
if (family == NFPROTO_IPV4)
err = tcf_ct_ipv4_is_fragment(skb, &frag);
else
err = tcf_ct_ipv6_is_fragment(skb, &frag);
if (err || !frag)
return err;
skb_get(skb);
err = nf_ct_handle_fragments(net, skb, zone, family, &proto, &mru);
if (err)
return err;
*defrag = true;
tc_skb_cb(skb)->mru = mru;
return 0;
}
static void tcf_ct_params_free(struct tcf_ct_params *params)
{
if (params->helper) {
#if IS_ENABLED(CONFIG_NF_NAT)
if (params->ct_action & TCA_CT_ACT_NAT)
nf_nat_helper_put(params->helper);
#endif
nf_conntrack_helper_put(params->helper);
}
if (params->ct_ft)
tcf_ct_flow_table_put(params->ct_ft);
if (params->tmpl)
nf_ct_put(params->tmpl);
kfree(params);
}
static void tcf_ct_params_free_rcu(struct rcu_head *head)
{
struct tcf_ct_params *params;
params = container_of(head, struct tcf_ct_params, rcu);
tcf_ct_params_free(params);
}
static void tcf_ct_act_set_mark(struct nf_conn *ct, u32 mark, u32 mask)
{
#if IS_ENABLED(CONFIG_NF_CONNTRACK_MARK)
u32 new_mark;
if (!mask)
return;
new_mark = mark | (READ_ONCE(ct->mark) & ~(mask));
if (READ_ONCE(ct->mark) != new_mark) {
WRITE_ONCE(ct->mark, new_mark);
if (nf_ct_is_confirmed(ct))
nf_conntrack_event_cache(IPCT_MARK, ct);
}
#endif
}
static void tcf_ct_act_set_labels(struct nf_conn *ct,
u32 *labels,
u32 *labels_m)
{
#if IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS)
size_t labels_sz = sizeof_field(struct tcf_ct_params, labels);
if (!memchr_inv(labels_m, 0, labels_sz))
return;
nf_connlabels_replace(ct, labels, labels_m, 4);
#endif
}
static int tcf_ct_act_nat(struct sk_buff *skb,
struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
int ct_action,
struct nf_nat_range2 *range,
bool commit)
{
#if IS_ENABLED(CONFIG_NF_NAT)
int err, action = 0;
if (!(ct_action & TCA_CT_ACT_NAT))
return NF_ACCEPT;
if (ct_action & TCA_CT_ACT_NAT_SRC)
action |= BIT(NF_NAT_MANIP_SRC);
if (ct_action & TCA_CT_ACT_NAT_DST)
action |= BIT(NF_NAT_MANIP_DST);
err = nf_ct_nat(skb, ct, ctinfo, &action, range, commit);
if (action & BIT(NF_NAT_MANIP_SRC))
tc_skb_cb(skb)->post_ct_snat = 1;
if (action & BIT(NF_NAT_MANIP_DST))
tc_skb_cb(skb)->post_ct_dnat = 1;
return err;
#else
return NF_ACCEPT;
#endif
}
TC_INDIRECT_SCOPE int tcf_ct_act(struct sk_buff *skb, const struct tc_action *a,
struct tcf_result *res)
{
struct net *net = dev_net(skb->dev);
enum ip_conntrack_info ctinfo;
struct tcf_ct *c = to_ct(a);
struct nf_conn *tmpl = NULL;
struct nf_hook_state state;
bool cached, commit, clear;
int nh_ofs, err, retval;
struct tcf_ct_params *p;
bool add_helper = false;
bool skip_add = false;
bool defrag = false;
struct nf_conn *ct;
u8 family;
p = rcu_dereference_bh(c->params);
retval = READ_ONCE(c->tcf_action);
commit = p->ct_action & TCA_CT_ACT_COMMIT;
clear = p->ct_action & TCA_CT_ACT_CLEAR;
tmpl = p->tmpl;
tcf_lastuse_update(&c->tcf_tm);
tcf_action_update_bstats(&c->common, skb);
if (clear) {
tc_skb_cb(skb)->post_ct = false;
ct = nf_ct_get(skb, &ctinfo);
if (ct) {
nf_ct_put(ct);
nf_ct_set(skb, NULL, IP_CT_UNTRACKED);
}
goto out_clear;
}
family = tcf_ct_skb_nf_family(skb);
if (family == NFPROTO_UNSPEC)
goto drop;
/* The conntrack module expects to be working at L3.
* We also try to pull the IPv4/6 header to linear area
*/
nh_ofs = skb_network_offset(skb);
skb_pull_rcsum(skb, nh_ofs);
err = tcf_ct_handle_fragments(net, skb, family, p->zone, &defrag);
if (err == -EINPROGRESS) {
retval = TC_ACT_STOLEN;
goto out_clear;
}
if (err)
goto drop;
err = nf_ct_skb_network_trim(skb, family);
if (err)
goto drop;
/* If we are recirculating packets to match on ct fields and
* committing with a separate ct action, then we don't need to
* actually run the packet through conntrack twice unless it's for a
* different zone.
*/
cached = tcf_ct_skb_nfct_cached(net, skb, p);
if (!cached) {
if (tcf_ct_flow_table_lookup(p, skb, family)) {
skip_add = true;
goto do_nat;
}
/* Associate skb with specified zone. */
if (tmpl) {
nf_conntrack_put(skb_nfct(skb));
nf_conntrack_get(&tmpl->ct_general);
nf_ct_set(skb, tmpl, IP_CT_NEW);
}
state.hook = NF_INET_PRE_ROUTING;
state.net = net;
state.pf = family;
err = nf_conntrack_in(skb, &state);
if (err != NF_ACCEPT)
goto out_push;
}
do_nat:
ct = nf_ct_get(skb, &ctinfo);
if (!ct)
goto out_push;
nf_ct_deliver_cached_events(ct);
nf_conn_act_ct_ext_fill(skb, ct, ctinfo);
err = tcf_ct_act_nat(skb, ct, ctinfo, p->ct_action, &p->range, commit);
if (err != NF_ACCEPT)
goto drop;
if (!nf_ct_is_confirmed(ct) && commit && p->helper && !nfct_help(ct)) {
err = __nf_ct_try_assign_helper(ct, p->tmpl, GFP_ATOMIC);
if (err)
goto drop;
add_helper = true;