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net/sched: act_ct: Software offload of established flows

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Offload nf conntrack processing by looking up the 5-tuple in the
zone's flow table.

The nf conntrack module will process the packets until a connection is
in established state. Once in established state, the ct state pointer
(nf_conn) will be restored on the skb from a successful ft lookup.

Signed-off-by: Paul Blakey <paulb@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Paul Blakey 2020-03-03 15:07:51 +02:00 committed by David S. Miller
parent 64ff70b80f
commit 46475bb20f
1 changed files with 158 additions and 2 deletions
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160
net/sched/act_ct.c
View file

@ -186,6 +186,155 @@ static void tcf_ct_flow_table_process_conn(struct tcf_ct_flow_table *ct_ft,
tcf_ct_flow_table_add(ct_ft, ct, tcp);
}
static bool
tcf_ct_flow_table_fill_tuple_ipv4(struct sk_buff *skb,
struct flow_offload_tuple *tuple)
{
struct flow_ports *ports;
unsigned int thoff;
struct iphdr *iph;
if (!pskb_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;
if (iph->protocol != IPPROTO_TCP &&
iph->protocol != IPPROTO_UDP)
return false;
if (iph->ttl <= 1)
return false;
if (!pskb_may_pull(skb, thoff + sizeof(*ports)))
return false;
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;
return true;
}
static bool
tcf_ct_flow_table_fill_tuple_ipv6(struct sk_buff *skb,
struct flow_offload_tuple *tuple)
{
struct flow_ports *ports;
struct ipv6hdr *ip6h;
unsigned int thoff;
if (!pskb_may_pull(skb, sizeof(*ip6h)))
return false;
ip6h = ipv6_hdr(skb);
if (ip6h->nexthdr != IPPROTO_TCP &&
ip6h->nexthdr != IPPROTO_UDP)
return false;
if (ip6h->hop_limit <= 1)
return false;
thoff = sizeof(*ip6h);
if (!pskb_may_pull(skb, thoff + sizeof(*ports)))
return false;
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;
return true;
}
static bool tcf_ct_flow_table_check_tcp(struct flow_offload *flow,
struct sk_buff *skb,
unsigned int thoff)
{
struct tcphdr *tcph;
if (!pskb_may_pull(skb, thoff + sizeof(*tcph)))
return false;
tcph = (void *)(skb_network_header(skb) + thoff);
if (unlikely(tcph->fin || tcph->rst)) {
flow_offload_teardown(flow);
return false;
}
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 flow_offload *flow;
struct nf_conn *ct;
unsigned int thoff;
int ip_proto;
u8 dir;
/* Previously seen or loopback */
ct = nf_ct_get(skb, &ctinfo);
if ((ct && !nf_ct_is_template(ct)) || ctinfo == IP_CT_UNTRACKED)
return false;
switch (family) {
case NFPROTO_IPV4:
if (!tcf_ct_flow_table_fill_tuple_ipv4(skb, &tuple))
return false;
break;
case NFPROTO_IPV6:
if (!tcf_ct_flow_table_fill_tuple_ipv6(skb, &tuple))
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;
ctinfo = dir == FLOW_OFFLOAD_DIR_ORIGINAL ? IP_CT_ESTABLISHED :
IP_CT_ESTABLISHED_REPLY;
thoff = ip_hdr(skb)->ihl * 4;
ip_proto = ip_hdr(skb)->protocol;
if (ip_proto == IPPROTO_TCP &&
!tcf_ct_flow_table_check_tcp(flow, skb, thoff))
return false;
nf_conntrack_get(&ct->ct_general);
nf_ct_set(skb, ct, ctinfo);
return true;
}
static int tcf_ct_flow_tables_init(void)
{
return rhashtable_init(&zones_ht, &zones_params);
@ -554,6 +703,7 @@ static int tcf_ct_act(struct sk_buff *skb, const struct tc_action *a,
struct nf_hook_state state;
int nh_ofs, err, retval;
struct tcf_ct_params *p;
bool skip_add = false;
struct nf_conn *ct;
u8 family;
@ -603,6 +753,11 @@ static int tcf_ct_act(struct sk_buff *skb, const struct tc_action *a,
*/
cached = tcf_ct_skb_nfct_cached(net, skb, p->zone, force);
if (!cached) {
if (!commit && tcf_ct_flow_table_lookup(p, skb, family)) {
skip_add = true;
goto do_nat;
}
/* Associate skb with specified zone. */
if (tmpl) {
ct = nf_ct_get(skb, &ctinfo);
@ -620,6 +775,7 @@ static int tcf_ct_act(struct sk_buff *skb, const struct tc_action *a,
goto out_push;
}
do_nat:
ct = nf_ct_get(skb, &ctinfo);
if (!ct)
goto out_push;
@ -637,10 +793,10 @@ static int tcf_ct_act(struct sk_buff *skb, const struct tc_action *a,
* even if the connection is already confirmed.
*/
nf_conntrack_confirm(skb);
} else if (!skip_add) {
tcf_ct_flow_table_process_conn(p->ct_ft, ct, ctinfo);
}
tcf_ct_flow_table_process_conn(p->ct_ft, ct, ctinfo);
out_push:
skb_push_rcsum(skb, nh_ofs);