- 根目录:
- net
- openvswitch
- conntrack.c
/*
* Copyright (c) 2015 Nicira, Inc.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#include <linux/module.h>
#include <linux/openvswitch.h>
#include <net/ip.h>
#include <net/netfilter/nf_conntrack_core.h>
#include <net/netfilter/nf_conntrack_helper.h>
#include <net/netfilter/nf_conntrack_labels.h>
#include <net/netfilter/nf_conntrack_zones.h>
#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
#include "datapath.h"
#include "conntrack.h"
#include "flow.h"
#include "flow_netlink.h"
struct ovs_ct_len_tbl {
size_t maxlen;
size_t minlen;
};
/* Metadata mark for masked write to conntrack mark */
struct md_mark {
u32 value;
u32 mask;
};
/* Metadata label for masked write to conntrack label. */
struct md_labels {
struct ovs_key_ct_labels value;
struct ovs_key_ct_labels mask;
};
/* Conntrack action context for execution. */
struct ovs_conntrack_info {
struct nf_conntrack_helper *helper;
struct nf_conntrack_zone zone;
struct nf_conn *ct;
u8 commit : 1;
u16 family;
struct md_mark mark;
struct md_labels labels;
};
static void __ovs_ct_free_action(struct ovs_conntrack_info *ct_info);
static u16 key_to_nfproto(const struct sw_flow_key *key)
{
switch (ntohs(key->eth.type)) {
case ETH_P_IP:
return NFPROTO_IPV4;
case ETH_P_IPV6:
return NFPROTO_IPV6;
default:
return NFPROTO_UNSPEC;
}
}
/* Map SKB connection state into the values used by flow definition. */
static u8 ovs_ct_get_state(enum ip_conntrack_info ctinfo)
{
u8 ct_state = OVS_CS_F_TRACKED;
switch (ctinfo) {
case IP_CT_ESTABLISHED_REPLY:
case IP_CT_RELATED_REPLY:
case IP_CT_NEW_REPLY:
ct_state |= OVS_CS_F_REPLY_DIR;
break;
default:
break;
}
switch (ctinfo) {
case IP_CT_ESTABLISHED:
case IP_CT_ESTABLISHED_REPLY:
ct_state |= OVS_CS_F_ESTABLISHED;
break;
case IP_CT_RELATED:
case IP_CT_RELATED_REPLY:
ct_state |= OVS_CS_F_RELATED;
break;
case IP_CT_NEW:
case IP_CT_NEW_REPLY:
ct_state |= OVS_CS_F_NEW;
break;
default:
break;
}
return ct_state;
}
static u32 ovs_ct_get_mark(const struct nf_conn *ct)
{
#if IS_ENABLED(CONFIG_NF_CONNTRACK_MARK)
return ct ? ct->mark : 0;
#else
return 0;
#endif
}
static void ovs_ct_get_labels(const struct nf_conn *ct,
struct ovs_key_ct_labels *labels)
{
struct nf_conn_labels *cl = ct ? nf_ct_labels_find(ct) : NULL;
if (cl) {
size_t len = cl->words * sizeof(long);
if (len > OVS_CT_LABELS_LEN)
len = OVS_CT_LABELS_LEN;
else if (len < OVS_CT_LABELS_LEN)
memset(labels, 0, OVS_CT_LABELS_LEN);
memcpy(labels, cl->bits, len);
} else {
memset(labels, 0, OVS_CT_LABELS_LEN);
}
}
static void __ovs_ct_update_key(struct sw_flow_key *key, u8 state,
const struct nf_conntrack_zone *zone,
const struct nf_conn *ct)
{
key->ct.state = state;
key->ct.zone = zone->id;
key->ct.mark = ovs_ct_get_mark(ct);
ovs_ct_get_labels(ct, &key->ct.labels);
}
/* Update 'key' based on skb->nfct. If 'post_ct' is true, then OVS has
* previously sent the packet to conntrack via the ct action.
*/
static void ovs_ct_update_key(const struct sk_buff *skb,
const struct ovs_conntrack_info *info,
struct sw_flow_key *key, bool post_ct)
{
const struct nf_conntrack_zone *zone = &nf_ct_zone_dflt;
enum ip_conntrack_info ctinfo;
struct nf_conn *ct;
u8 state = 0;
ct = nf_ct_get(skb, &ctinfo);
if (ct) {
state = ovs_ct_get_state(ctinfo);
if (!nf_ct_is_confirmed(ct))
state |= OVS_CS_F_NEW;
if (ct->master)
state |= OVS_CS_F_RELATED;
zone = nf_ct_zone(ct);
} else if (post_ct) {
state = OVS_CS_F_TRACKED | OVS_CS_F_INVALID;
if (info)
zone = &info->zone;
}
__ovs_ct_update_key(key, state, zone, ct);
}
void ovs_ct_fill_key(const struct sk_buff *skb, struct sw_flow_key *key)
{
ovs_ct_update_key(skb, NULL, key, false);
}
int ovs_ct_put_key(const struct sw_flow_key *key, struct sk_buff *skb)
{
if (nla_put_u32(skb, OVS_KEY_ATTR_CT_STATE, key->ct.state))
return -EMSGSIZE;
if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
nla_put_u16(skb, OVS_KEY_ATTR_CT_ZONE, key->ct.zone))
return -EMSGSIZE;
if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) &&
nla_put_u32(skb, OVS_KEY_ATTR_CT_MARK, key->ct.mark))
return -EMSGSIZE;
if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
nla_put(skb, OVS_KEY_ATTR_CT_LABELS, sizeof(key->ct.labels),
&key->ct.labels))
return -EMSGSIZE;
return 0;
}
static int ovs_ct_set_mark(struct sk_buff *skb, struct sw_flow_key *key,
u32 ct_mark, u32 mask)
{
#if IS_ENABLED(CONFIG_NF_CONNTRACK_MARK)
enum ip_conntrack_info ctinfo;
struct nf_conn *ct;
u32 new_mark;
/* The connection could be invalid, in which case set_mark is no-op. */
ct = nf_ct_get(skb, &ctinfo);
if (!ct)
return 0;
new_mark = ct_mark | (ct->mark & ~(mask));
if (ct->mark != new_mark) {
ct->mark = new_mark;
nf_conntrack_event_cache(IPCT_MARK, ct);
key->ct.mark = new_mark;
}
return 0;
#else
return -ENOTSUPP;
#endif
}
static int ovs_ct_set_labels(struct sk_buff *skb, struct sw_flow_key *key,
const struct ovs_key_ct_labels *labels,
const struct ovs_key_ct_labels *mask)
{
enum ip_conntrack_info ctinfo;
struct nf_conn_labels *cl;
struct nf_conn *ct;
int err;
/* The connection could be invalid, in which case set_label is no-op.*/
ct = nf_ct_get(skb, &ctinfo);
if (!ct)
return 0;
cl = nf_ct_labels_find(ct);
if (!cl) {
nf_ct_labels_ext_add(ct);
cl = nf_ct_labels_find(ct);
}
if (!cl || cl->words * sizeof(long) < OVS_CT_LABELS_LEN)
return -ENOSPC;
err = nf_connlabels_replace(ct, (u32 *)labels, (u32 *)mask,
OVS_CT_LABELS_LEN / sizeof(u32));
if (err)
return err;
ovs_ct_get_labels(ct, &key->ct.labels);
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;
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;
}
return helper->help(skb, protoff, ct, ctinfo);
}
/* Returns 0 on success, -EINPROGRESS if 'skb' is stolen, or other nonzero
* value if 'skb' is freed.
*/
static int handle_fragments(struct net *net, struct sw_flow_key *key,
u16 zone, struct sk_buff *skb)
{
struct ovs_skb_cb ovs_cb = *OVS_CB(skb);
if (key->eth.type == htons(ETH_P_IP)) {
enum ip_defrag_users user = IP_DEFRAG_CONNTRACK_IN + zone;
int err;
memset(IPCB(skb), 0, sizeof(struct inet_skb_parm));
err = ip_defrag(net, skb, user);
if (err)
return err;
ovs_cb.mru = IPCB(skb)->frag_max_size;
#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
} else if (key->eth.type == htons(ETH_P_IPV6)) {
enum ip6_defrag_users user = IP6_DEFRAG_CONNTRACK_IN + zone;
struct sk_buff *reasm;
memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
reasm = nf_ct_frag6_gather(net, skb, user);
if (!reasm)
return -EINPROGRESS;
if (skb == reasm) {
kfree_skb(skb);
return -EINVAL;
}
/* Don't free 'skb' even though it is one of the original
* fragments, as we're going to morph it into the head.
*/
skb_get(skb);
nf_ct_frag6_consume_orig(reasm);
key->ip.proto = ipv6_hdr(reasm)->nexthdr;
skb_morph(skb, reasm);
skb->next = reasm->next;
consume_skb(reasm);
ovs_cb.mru = IP6CB(skb)->frag_max_size;
#endif
} else {
kfree_skb(skb);
return -EPFNOSUPPORT;
}
key->ip.frag = OVS_FRAG_TYPE_NONE;
skb_clear_hash(skb);
skb->ignore_df = 1;
*OVS_CB(skb) = ovs_cb;
return 0;
}
static struct nf_conntrack_expect *
ovs_ct_expect_find(struct net *net, const struct nf_conntrack_zone *zone,
u16 proto, const struct sk_buff *skb)
{
struct nf_conntrack_tuple tuple;
if (!nf_ct_get_tuplepr(skb, skb_network_offset(skb), proto, net, &tuple))
return NULL;
return __nf_ct_expect_find(net, zone, &tuple);
}
/* Determine whether skb->nfct is equal to the result of conntrack lookup. */
static bool skb_nfct_cached(const struct net *net, const struct sk_buff *skb,
const struct ovs_conntrack_info *info)
{
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)))
return false;
if (!nf_ct_zone_equal_any(info->ct, nf_ct_zone(ct)))
return false;
if (info->helper) {
struct nf_conn_help *help;
help = nf_ct_ext_find(ct, NF_CT_EXT_HELPER);
if (help && rcu_access_pointer(help->helper) != info->helper)
return false;
}
return true;
}
static int __ovs_ct_lookup(struct net *net, struct sw_flow_key *key,
const struct ovs_conntrack_info *info,
struct sk_buff *skb)
{
/* If we are recirculating packets to match on conntrack fields and
* committing with a separate conntrack action, then we don't need to
* actually run the packet through conntrack twice unless it's for a
* different zone.
*/
if (!skb_nfct_cached(net, skb, info)) {
struct nf_conn *tmpl = info->ct;
/* Associate skb with specified zone. */
if (tmpl) {
if (skb->nfct)
nf_conntrack_put(skb->nfct);
nf_conntrack_get(&tmpl->ct_general);
skb->nfct = &tmpl->ct_general;
skb->nfctinfo = IP_CT_NEW;
}
if (nf_conntrack_in(net, info->family, NF_INET_PRE_ROUTING,
skb) != NF_ACCEPT)
return -ENOENT;
if (ovs_ct_helper(skb, info->family) != NF_ACCEPT) {
WARN_ONCE(1, "helper rejected packet");
return -EINVAL;
}
}
ovs_ct_update_key(skb, info, key, true);
return 0;
}
/* Lookup connection and read fields into key. */
static int ovs_ct_lookup(struct net *net, struct sw_flow_key *key,
const struct ovs_conntrack_info *info,
struct sk_buff *skb)
{
struct nf_conntrack_expect *exp;
exp = ovs_ct_expect_find(net, &info->zone, info->family, skb);
if (exp) {
u8 state;
state = OVS_CS_F_TRACKED | OVS_CS_F_NEW | OVS_CS_F_RELATED;
__ovs_ct_update_key(key, state, &info->zone, exp->master);
} else {
int err;
err = __ovs_ct_lookup(net, key, info, skb);
if (err)
return err;
}
return 0;
}
/* Lookup connection and confirm if unconfirmed. */
static int ovs_ct_commit(struct net *net, struct sw_flow_key *key,
const struct ovs_conntrack_info *info,
struct sk_buff *skb)
{
u8 state;
int err;
state = key->ct.state;
if (key->ct.zone == info->zone.id &&
((state & OVS_CS_F_TRACKED) && !(state & OVS_CS_F_NEW))) {
/* Previous lookup has shown that this connection is already
* tracked and committed. Skip committing.
*/
return 0;
}
err = __ovs_ct_lookup(net, key, info, skb);
if (err)
return err;
if (nf_conntrack_confirm(skb) != NF_ACCEPT)
return -EINVAL;
return 0;
}
static bool labels_nonzero(const struct ovs_key_ct_labels *labels)
{
size_t i;
for (i = 0; i < sizeof(*labels); i++)
if (labels->ct_labels[i])
return true;
return false;
}
/* Returns 0 on success, -EINPROGRESS if 'skb' is stolen, or other nonzero
* value if 'skb' is freed.
*/
int ovs_ct_execute(struct net *net, struct sk_buff *skb,
struct sw_flow_key *key,
const struct ovs_conntrack_info *info)
{
int nh_ofs;
int err;
/* The conntrack module expects to be working at L3. */
nh_ofs = skb_network_offset(skb);
skb_pull(skb, nh_ofs);
if (key->ip.frag != OVS_FRAG_TYPE_NONE) {
err = handle_fragments(net, key, info->zone.id, skb);
if (err)
return err;
}
if (info->commit)
err = ovs_ct_commit(net, key, info, skb);
else
err = ovs_ct_lookup(net, key, info, skb);
if (err)
goto err;
if (info->mark.mask) {
err = ovs_ct_set_mark(skb, key, info->mark.value,
info->mark.mask);
if (err)
goto err;
}
if (labels_nonzero(&info->labels.mask))
err = ovs_ct_set_labels(skb, key, &info->labels.value,
&info->labels.mask);
err:
skb_push(skb, nh_ofs);
if (err)
kfree_skb(skb);
return err;
}
static int ovs_ct_add_helper(struct ovs_conntrack_info *info, const char *name,
const struct sw_flow_key *key, bool log)
{
struct nf_conntrack_helper *helper;
struct nf_conn_help *help;
helper = nf_conntrack_helper_try_module_get(name, info->family,
key->ip.proto);
if (!helper) {
OVS_NLERR(log, "Unknown helper \"%s\"", name);
return -EINVAL;
}
help = nf_ct_helper_ext_add(info->ct, helper, GFP_KERNEL);
if (!help) {
module_put(helper->me);
return -ENOMEM;
}
rcu_assign_pointer(help->helper, helper);
info->helper = helper;
return 0;
}
static const struct ovs_ct_len_tbl ovs_ct_attr_lens[OVS_CT_ATTR_MAX + 1] = {
[OVS_CT_ATTR_COMMIT] = { .minlen = 0, .maxlen = 0 },
[OVS_CT_ATTR_ZONE] = { .minlen = sizeof(u16),
.maxlen = sizeof(u16) },
[OVS_CT_ATTR_MARK] = { .minlen = sizeof(struct md_mark),
.maxlen = sizeof(struct md_mark) },
[OVS_CT_ATTR_LABELS] = { .minlen = sizeof(struct md_labels),
.maxlen = sizeof(struct md_labels) },
[OVS_CT_ATTR_HELPER] = { .minlen = 1,
.maxlen = NF_CT_HELPER_NAME_LEN }
};
static int parse_ct(const struct nlattr *attr, struct ovs_conntrack_info *info,
const char **helper, bool log)
{
struct nlattr *a;
int rem;
nla_for_each_nested(a, attr, rem) {
int type = nla_type(a);
int maxlen = ovs_ct_attr_lens[type].maxlen;
int minlen = ovs_ct_attr_lens[type].minlen;
if (type > OVS_CT_ATTR_MAX) {
OVS_NLERR(log,
"Unknown conntrack attr (type=%d, max=%d)",
type, OVS_CT_ATTR_MAX);
return -EINVAL;
}
if (nla_len(a) < minlen || nla_len(a) > maxlen) {
OVS_NLERR(log,
"Conntrack attr type has unexpected length (type=%d, length=%d, expected=%d)",
type, nla_len(a), maxlen);
return -EINVAL;
}
switch (type) {
case OVS_CT_ATTR_COMMIT:
info->commit = true;
break;
#ifdef CONFIG_NF_CONNTRACK_ZONES
case OVS_CT_ATTR_ZONE:
info->zone.id = nla_get_u16(a);
break;
#endif
#ifdef CONFIG_NF_CONNTRACK_MARK
case OVS_CT_ATTR_MARK: {
struct md_mark *mark = nla_data(a);
if (!mark->mask) {
OVS_NLERR(log, "ct_mark mask cannot be 0");
return -EINVAL;
}
info->mark = *mark;
break;
}
#endif
#ifdef CONFIG_NF_CONNTRACK_LABELS
case OVS_CT_ATTR_LABELS: {
struct md_labels *labels = nla_data(a);
if (!labels_nonzero(&labels->mask)) {
OVS_NLERR(log, "ct_labels mask cannot be 0");
return -EINVAL;
}
info->labels = *labels;
break;
}
#endif
case OVS_CT_ATTR_HELPER:
*helper = nla_data(a);
if (!memchr(*helper, '\0', nla_len(a))) {
OVS_NLERR(log, "Invalid conntrack helper");
return -EINVAL;
}
break;
default:
OVS_NLERR(log, "Unknown conntrack attr (%d)",
type);
return -EINVAL;
}
}
if (rem > 0) {
OVS_NLERR(log, "Conntrack attr has %d unknown bytes", rem);
return -EINVAL;
}
return 0;
}
bool ovs_ct_verify(struct net *net, enum ovs_key_attr attr)
{
if (attr == OVS_KEY_ATTR_CT_STATE)
return true;
if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
attr == OVS_KEY_ATTR_CT_ZONE)
return true;
if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) &&
attr == OVS_KEY_ATTR_CT_MARK)
return true;
if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
attr == OVS_KEY_ATTR_CT_LABELS) {
struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
return ovs_net->xt_label;
}
return false;
}
int ovs_ct_copy_action(struct net *net, const struct nlattr *attr,
const struct sw_flow_key *key,
struct sw_flow_actions **sfa, bool log)
{
struct ovs_conntrack_info ct_info;
const char *helper = NULL;
u16 family;
int err;
family = key_to_nfproto(key);
if (family == NFPROTO_UNSPEC) {
OVS_NLERR(log, "ct family unspecified");
return -EINVAL;
}
memset(&ct_info, 0, sizeof(ct_info));
ct_info.family = family;
nf_ct_zone_init(&ct_info.zone, NF_CT_DEFAULT_ZONE_ID,
NF_CT_DEFAULT_ZONE_DIR, 0);
err = parse_ct(attr, &ct_info, &helper, log);
if (err)
return err;
/* Set up template for tracking connections in specific zones. */
ct_info.ct = nf_ct_tmpl_alloc(net, &ct_info.zone, GFP_KERNEL);
if (!ct_info.ct) {
OVS_NLERR(log, "Failed to allocate conntrack template");
return -ENOMEM;
}
__set_bit(IPS_CONFIRMED_BIT, &ct_info.ct->status);
nf_conntrack_get(&ct_info.ct->ct_general);
if (helper) {
err = ovs_ct_add_helper(&ct_info, helper, key, log);
if (err)
goto err_free_ct;
}
err = ovs_nla_add_action(sfa, OVS_ACTION_ATTR_CT, &ct_info,
sizeof(ct_info), log);
if (err)
goto err_free_ct;
return 0;
err_free_ct:
__ovs_ct_free_action(&ct_info);
return err;
}
int ovs_ct_action_to_attr(const struct ovs_conntrack_info *ct_info,
struct sk_buff *skb)
{
struct nlattr *start;
start = nla_nest_start(skb, OVS_ACTION_ATTR_CT);
if (!start)
return -EMSGSIZE;
if (ct_info->commit && nla_put_flag(skb, OVS_CT_ATTR_COMMIT))
return -EMSGSIZE;
if (IS_ENABLED(CONFIG_NF_CONNTRACK_ZONES) &&
nla_put_u16(skb, OVS_CT_ATTR_ZONE, ct_info->zone.id))
return -EMSGSIZE;
if (IS_ENABLED(CONFIG_NF_CONNTRACK_MARK) && ct_info->mark.mask &&
nla_put(skb, OVS_CT_ATTR_MARK, sizeof(ct_info->mark),
&ct_info->mark))
return -EMSGSIZE;
if (IS_ENABLED(CONFIG_NF_CONNTRACK_LABELS) &&
labels_nonzero(&ct_info->labels.mask) &&
nla_put(skb, OVS_CT_ATTR_LABELS, sizeof(ct_info->labels),
&ct_info->labels))
return -EMSGSIZE;
if (ct_info->helper) {
if (nla_put_string(skb, OVS_CT_ATTR_HELPER,
ct_info->helper->name))
return -EMSGSIZE;
}
nla_nest_end(skb, start);
return 0;
}
void ovs_ct_free_action(const struct nlattr *a)
{
struct ovs_conntrack_info *ct_info = nla_data(a);
__ovs_ct_free_action(ct_info);
}
static void __ovs_ct_free_action(struct ovs_conntrack_info *ct_info)
{
if (ct_info->helper)
module_put(ct_info->helper->me);
if (ct_info->ct)
nf_ct_put(ct_info->ct);
}
void ovs_ct_init(struct net *net)
{
unsigned int n_bits = sizeof(struct ovs_key_ct_labels) * BITS_PER_BYTE;
struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
if (nf_connlabels_get(net, n_bits)) {
ovs_net->xt_label = false;
OVS_NLERR(true, "Failed to set connlabel length");
} else {
ovs_net->xt_label = true;
}
}
void ovs_ct_exit(struct net *net)
{
struct ovs_net *ovs_net = net_generic(net, ovs_net_id);
if (ovs_net->xt_label)
nf_connlabels_put(net);
}