net: move the ct helper function to nf_conntrack_helper for ovs and tc

Move ovs_ct_helper from openvswitch to nf_conntrack_helper and rename
as nf_ct_helper so that it can be used in TC act_ct in the next patch.
Note that it also adds the checks for the family and proto, as in TC
act_ct, the packets with correct family and proto are not guaranteed.

Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Xin Long 2022-11-06 15:34:14 -05:00 committed by Paolo Abeni
parent 47f3ecf476
commit ca71277f36
3 changed files with 73 additions and 60 deletions

View File

@ -115,6 +115,9 @@ struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp);
int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
gfp_t flags);
int nf_ct_helper(struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo, u16 proto);
void nf_ct_helper_destroy(struct nf_conn *ct);
static inline struct nf_conn_help *nfct_help(const struct nf_conn *ct)

View File

@ -26,7 +26,9 @@
#include <net/netfilter/nf_conntrack_extend.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_l4proto.h>
#include <net/netfilter/nf_conntrack_seqadj.h>
#include <net/netfilter/nf_log.h>
#include <net/ip.h>
static DEFINE_MUTEX(nf_ct_helper_mutex);
struct hlist_head *nf_ct_helper_hash __read_mostly;
@ -240,6 +242,73 @@ int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl,
}
EXPORT_SYMBOL_GPL(__nf_ct_try_assign_helper);
/* 'skb' should already be pulled to nh_ofs. */
int nf_ct_helper(struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo, u16 proto)
{
const struct nf_conntrack_helper *helper;
const struct nf_conn_help *help;
unsigned int protoff;
int err;
if (ctinfo == IP_CT_RELATED_REPLY)
return NF_ACCEPT;
help = nfct_help(ct);
if (!help)
return NF_ACCEPT;
helper = rcu_dereference(help->helper);
if (!helper)
return NF_ACCEPT;
if (helper->tuple.src.l3num != NFPROTO_UNSPEC &&
helper->tuple.src.l3num != proto)
return NF_ACCEPT;
switch (proto) {
case NFPROTO_IPV4:
protoff = ip_hdrlen(skb);
proto = ip_hdr(skb)->protocol;
break;
case NFPROTO_IPV6: {
u8 nexthdr = ipv6_hdr(skb)->nexthdr;
__be16 frag_off;
int ofs;
ofs = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr,
&frag_off);
if (ofs < 0 || (frag_off & htons(~0x7)) != 0) {
pr_debug("proto header not found\n");
return NF_ACCEPT;
}
protoff = ofs;
proto = nexthdr;
break;
}
default:
WARN_ONCE(1, "helper invoked on non-IP family!");
return NF_DROP;
}
if (helper->tuple.dst.protonum != proto)
return NF_ACCEPT;
err = helper->help(skb, protoff, ct, ctinfo);
if (err != NF_ACCEPT)
return err;
/* Adjust seqs after helper. This is needed due to some helpers (e.g.,
* FTP with NAT) adusting the TCP payload size when mangling IP
* addresses and/or port numbers in the text-based control connection.
*/
if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
!nf_ct_seq_adjust(skb, ct, ctinfo, protoff))
return NF_DROP;
return NF_ACCEPT;
}
EXPORT_SYMBOL_GPL(nf_ct_helper);
/* appropriate ct lock protecting must be taken by caller */
static int unhelp(struct nf_conn *ct, void *me)
{

View File

@ -434,65 +434,6 @@ static int ovs_ct_set_labels(struct nf_conn *ct, struct sw_flow_key *key,
return 0;
}
/* 'skb' should already be pulled to nh_ofs. */
static int ovs_ct_helper(struct sk_buff *skb, u16 proto)
{
const struct nf_conntrack_helper *helper;
const struct nf_conn_help *help;
enum ip_conntrack_info ctinfo;
unsigned int protoff;
struct nf_conn *ct;
int err;
ct = nf_ct_get(skb, &ctinfo);
if (!ct || ctinfo == IP_CT_RELATED_REPLY)
return NF_ACCEPT;
help = nfct_help(ct);
if (!help)
return NF_ACCEPT;
helper = rcu_dereference(help->helper);
if (!helper)
return NF_ACCEPT;
switch (proto) {
case NFPROTO_IPV4:
protoff = ip_hdrlen(skb);
break;
case NFPROTO_IPV6: {
u8 nexthdr = ipv6_hdr(skb)->nexthdr;
__be16 frag_off;
int ofs;
ofs = ipv6_skip_exthdr(skb, sizeof(struct ipv6hdr), &nexthdr,
&frag_off);
if (ofs < 0 || (frag_off & htons(~0x7)) != 0) {
pr_debug("proto header not found\n");
return NF_ACCEPT;
}
protoff = ofs;
break;
}
default:
WARN_ONCE(1, "helper invoked on non-IP family!");
return NF_DROP;
}
err = helper->help(skb, protoff, ct, ctinfo);
if (err != NF_ACCEPT)
return err;
/* Adjust seqs after helper. This is needed due to some helpers (e.g.,
* FTP with NAT) adusting the TCP payload size when mangling IP
* addresses and/or port numbers in the text-based control connection.
*/
if (test_bit(IPS_SEQ_ADJUST_BIT, &ct->status) &&
!nf_ct_seq_adjust(skb, ct, ctinfo, protoff))
return NF_DROP;
return NF_ACCEPT;
}
/* Returns 0 on success, -EINPROGRESS if 'skb' is stolen, or other nonzero
* value if 'skb' is freed.
*/
@ -1038,7 +979,7 @@ static int __ovs_ct_lookup(struct net *net, struct sw_flow_key *key,
*/
if ((nf_ct_is_confirmed(ct) ? !cached || add_helper :
info->commit) &&
ovs_ct_helper(skb, info->family) != NF_ACCEPT) {
nf_ct_helper(skb, ct, ctinfo, info->family) != NF_ACCEPT) {
return -EINVAL;
}