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linux/net/openvswitch/conntrack.c

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/*
* 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 <linux/tcp.h>
#include <linux/udp.h>
#include <linux/sctp.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_seqadj.h>
#include <net/netfilter/nf_conntrack_zones.h>
#include <net/netfilter/ipv6/nf_defrag_ipv6.h>
#ifdef CONFIG_NF_NAT_NEEDED
#include <linux/netfilter/nf_nat.h>
#include <net/netfilter/nf_nat_core.h>
#include <net/netfilter/nf_nat_l3proto.h>
#endif
#include "datapath.h"
#include "conntrack.h"
#include "flow.h"
#include "flow_netlink.h"
struct ovs_ct_len_tbl {
int maxlen;
int 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;
};
enum ovs_ct_nat {
OVS_CT_NAT = 1 << 0, /* NAT for committed connections only. */
OVS_CT_SRC_NAT = 1 << 1, /* Source NAT for NEW connections. */
OVS_CT_DST_NAT = 1 << 2, /* Destination NAT for NEW connections. */
};
/* 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;
u8 nat : 3; /* enum ovs_ct_nat */
u16 family;
struct md_mark mark;
struct md_labels labels;
#ifdef CONFIG_NF_NAT_NEEDED
struct nf_nat_range range; /* Only present for SRC NAT and DST NAT. */
#endif
};
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:
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:
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 = sizeof(cl->bits);
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. If
* 'keep_nat_flags' is true, the existing NAT flags retained, else they are
* initialized from the connection status.
*/
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,
bool keep_nat_flags)
{
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);
/* All unconfirmed entries are NEW connections. */
if (!nf_ct_is_confirmed(ct))
state |= OVS_CS_F_NEW;
/* OVS persists the related flag for the duration of the
* connection.
*/
if (ct->master)
state |= OVS_CS_F_RELATED;
if (keep_nat_flags) {
state |= key->ct.state & OVS_CS_F_NAT_MASK;
} else {
if (ct->status & IPS_SRC_NAT)
state |= OVS_CS_F_SRC_NAT;
if (ct->status & IPS_DST_NAT)
state |= OVS_CS_F_DST_NAT;
}
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);
}
/* This is called to initialize CT key fields possibly coming in from the local
* stack.
*/
void ovs_ct_fill_key(const struct sk_buff *skb, struct sw_flow_key *key)
{
ovs_ct_update_key(skb, NULL, key, false, 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 || sizeof(cl->bits) < 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;
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.
*/
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);
int err;
if (key->eth.type == htons(ETH_P_IP)) {
enum ip_defrag_users user = IP_DEFRAG_CONNTRACK_IN + zone;
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;
skb_orphan(skb);
memset(IP6CB(skb), 0, sizeof(struct inet6_skb_parm));
err = nf_ct_frag6_gather(net, skb, user);
if (err)
return err;
key->ip.proto = ipv6_hdr(skb)->nexthdr;
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);
}
/* This replicates logic from nf_conntrack_core.c that is not exported. */
static enum ip_conntrack_info
ovs_ct_get_info(const struct nf_conntrack_tuple_hash *h)
{
const struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(h);
if (NF_CT_DIRECTION(h) == IP_CT_DIR_REPLY)
return IP_CT_ESTABLISHED_REPLY;
/* Once we've had two way comms, always ESTABLISHED. */
if (test_bit(IPS_SEEN_REPLY_BIT, &ct->status))
return IP_CT_ESTABLISHED;
if (test_bit(IPS_EXPECTED_BIT, &ct->status))
return IP_CT_RELATED;
return IP_CT_NEW;
}
/* Find an existing connection which this packet belongs to without
* re-attributing statistics or modifying the connection state. This allows an
* skb->nfct lost due to an upcall to be recovered during actions execution.
*
* Must be called with rcu_read_lock.
*
* On success, populates skb->nfct and skb->nfctinfo, and returns the
* connection. Returns NULL if there is no existing entry.
*/
static struct nf_conn *
ovs_ct_find_existing(struct net *net, const struct nf_conntrack_zone *zone,
u8 l3num, struct sk_buff *skb)
{
struct nf_conntrack_l3proto *l3proto;
struct nf_conntrack_l4proto *l4proto;
struct nf_conntrack_tuple tuple;
struct nf_conntrack_tuple_hash *h;
struct nf_conn *ct;
unsigned int dataoff;
u8 protonum;
l3proto = __nf_ct_l3proto_find(l3num);
if (l3proto->get_l4proto(skb, skb_network_offset(skb), &dataoff,
&protonum) <= 0) {
pr_debug("ovs_ct_find_existing: Can't get protonum\n");
return NULL;
}
l4proto = __nf_ct_l4proto_find(l3num, protonum);
if (!nf_ct_get_tuple(skb, skb_network_offset(skb), dataoff, l3num,
protonum, net, &tuple, l3proto, l4proto)) {
pr_debug("ovs_ct_find_existing: Can't get tuple\n");
return NULL;
}
/* look for tuple match */
h = nf_conntrack_find_get(net, zone, &tuple);
if (!h)
return NULL; /* Not found. */
ct = nf_ct_tuplehash_to_ctrack(h);
skb->nfct = &ct->ct_general;
skb->nfctinfo = ovs_ct_get_info(h);
return ct;
}
/* Determine whether skb->nfct is equal to the result of conntrack lookup. */
static bool skb_nfct_cached(struct net *net,
const struct sw_flow_key *key,
const struct ovs_conntrack_info *info,
struct sk_buff *skb)
{
enum ip_conntrack_info ctinfo;
struct nf_conn *ct;
ct = nf_ct_get(skb, &ctinfo);
/* If no ct, check if we have evidence that an existing conntrack entry
* might be found for this skb. This happens when we lose a skb->nfct
* due to an upcall. If the connection was not confirmed, it is not
* cached and needs to be run through conntrack again.
*/
if (!ct && key->ct.state & OVS_CS_F_TRACKED &&
!(key->ct.state & OVS_CS_F_INVALID) &&
key->ct.zone == info->zone.id)
ct = ovs_ct_find_existing(net, &info->zone, info->family, skb);
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;
}
#ifdef CONFIG_NF_NAT_NEEDED
/* Modelled after nf_nat_ipv[46]_fn().
* range is only used for new, uninitialized NAT state.
* Returns either NF_ACCEPT or NF_DROP.
*/
static int ovs_ct_nat_execute(struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo,
const struct nf_nat_range *range,
enum nf_nat_manip_type maniptype)
{
int hooknum, nh_off, err = NF_ACCEPT;
nh_off = skb_network_offset(skb);
skb_pull(skb, nh_off);
/* See HOOK2MANIP(). */
if (maniptype == NF_NAT_MANIP_SRC)
hooknum = NF_INET_LOCAL_IN; /* Source NAT */
else
hooknum = NF_INET_LOCAL_OUT; /* Destination NAT */
switch (ctinfo) {
case IP_CT_RELATED:
case IP_CT_RELATED_REPLY:
if (IS_ENABLED(CONFIG_NF_NAT_IPV4) &&
skb->protocol == htons(ETH_P_IP) &&
ip_hdr(skb)->protocol == IPPROTO_ICMP) {
if (!nf_nat_icmp_reply_translation(skb, ct, ctinfo,
hooknum))
err = NF_DROP;
goto push;
} else if (IS_ENABLED(CONFIG_NF_NAT_IPV6) &&
skb->protocol == htons(ETH_P_IPV6)) {
__be16 frag_off;
u8 nexthdr = ipv6_hdr(skb)->nexthdr;
int hdrlen = ipv6_skip_exthdr(skb,
sizeof(struct ipv6hdr),
&nexthdr, &frag_off);
if (hdrlen >= 0 && nexthdr == IPPROTO_ICMPV6) {
if (!nf_nat_icmpv6_reply_translation(skb, ct,
ctinfo,
hooknum,
hdrlen))
err = NF_DROP;
goto push;
}
}
/* Non-ICMP, fall thru to initialize if needed. */
case IP_CT_NEW:
/* Seen it before? This can happen for loopback, retrans,
* or local packets.
*/
if (!nf_nat_initialized(ct, maniptype)) {
/* Initialize according to the NAT action. */
err = (range && range->flags & NF_NAT_RANGE_MAP_IPS)
/* Action is set up to establish a new
* mapping.
*/
? nf_nat_setup_info(ct, range, maniptype)
: nf_nat_alloc_null_binding(ct, hooknum);
if (err != NF_ACCEPT)
goto push;
}
break;
case IP_CT_ESTABLISHED:
case IP_CT_ESTABLISHED_REPLY:
break;
default:
err = NF_DROP;
goto push;
}
err = nf_nat_packet(ct, ctinfo, hooknum, skb);
push:
skb_push(skb, nh_off);
return err;
}
static void ovs_nat_update_key(struct sw_flow_key *key,
const struct sk_buff *skb,
enum nf_nat_manip_type maniptype)
{
if (maniptype == NF_NAT_MANIP_SRC) {
__be16 src;
key->ct.state |= OVS_CS_F_SRC_NAT;
if (key->eth.type == htons(ETH_P_IP))
key->ipv4.addr.src = ip_hdr(skb)->saddr;
else if (key->eth.type == htons(ETH_P_IPV6))
memcpy(&key->ipv6.addr.src, &ipv6_hdr(skb)->saddr,
sizeof(key->ipv6.addr.src));
else
return;
if (key->ip.proto == IPPROTO_UDP)
src = udp_hdr(skb)->source;
else if (key->ip.proto == IPPROTO_TCP)
src = tcp_hdr(skb)->source;
else if (key->ip.proto == IPPROTO_SCTP)
src = sctp_hdr(skb)->source;
else
return;
key->tp.src = src;
} else {
__be16 dst;
key->ct.state |= OVS_CS_F_DST_NAT;
if (key->eth.type == htons(ETH_P_IP))
key->ipv4.addr.dst = ip_hdr(skb)->daddr;
else if (key->eth.type == htons(ETH_P_IPV6))
memcpy(&key->ipv6.addr.dst, &ipv6_hdr(skb)->daddr,
sizeof(key->ipv6.addr.dst));
else
return;
if (key->ip.proto == IPPROTO_UDP)
dst = udp_hdr(skb)->dest;
else if (key->ip.proto == IPPROTO_TCP)
dst = tcp_hdr(skb)->dest;
else if (key->ip.proto == IPPROTO_SCTP)
dst = sctp_hdr(skb)->dest;
else
return;
key->tp.dst = dst;
}
}
/* Returns NF_DROP if the packet should be dropped, NF_ACCEPT otherwise. */
static int ovs_ct_nat(struct net *net, struct sw_flow_key *key,
const struct ovs_conntrack_info *info,
struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo)
{
enum nf_nat_manip_type maniptype;
int err;
if (nf_ct_is_untracked(ct)) {
/* A NAT action may only be performed on tracked packets. */
return NF_ACCEPT;
}
/* Add NAT extension if not confirmed yet. */
if (!nf_ct_is_confirmed(ct) && !nf_ct_nat_ext_add(ct))
return NF_ACCEPT; /* Can't NAT. */
/* Determine NAT type.
* Check if the NAT type can be deduced from the tracked connection.
* Make sure new expected connections (IP_CT_RELATED) are NATted only
* when committing.
*/
if (info->nat & OVS_CT_NAT && ctinfo != IP_CT_NEW &&
ct->status & IPS_NAT_MASK &&
(ctinfo != IP_CT_RELATED || info->commit)) {
/* NAT an established or related connection like before. */
if (CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY)
/* This is the REPLY direction for a connection
* for which NAT was applied in the forward
* direction. Do the reverse NAT.
*/
maniptype = ct->status & IPS_SRC_NAT
? NF_NAT_MANIP_DST : NF_NAT_MANIP_SRC;
else
maniptype = ct->status & IPS_SRC_NAT
? NF_NAT_MANIP_SRC : NF_NAT_MANIP_DST;
} else if (info->nat & OVS_CT_SRC_NAT) {
maniptype = NF_NAT_MANIP_SRC;
} else if (info->nat & OVS_CT_DST_NAT) {
maniptype = NF_NAT_MANIP_DST;
} else {
return NF_ACCEPT; /* Connection is not NATed. */
}
err = ovs_ct_nat_execute(skb, ct, ctinfo, &info->range, maniptype);
/* Mark NAT done if successful and update the flow key. */
if (err == NF_ACCEPT)
ovs_nat_update_key(key, skb, maniptype);
return err;
}
#else /* !CONFIG_NF_NAT_NEEDED */
static int ovs_ct_nat(struct net *net, struct sw_flow_key *key,
const struct ovs_conntrack_info *info,
struct sk_buff *skb, struct nf_conn *ct,
enum ip_conntrack_info ctinfo)
{
return NF_ACCEPT;
}
#endif
/* Pass 'skb' through conntrack in 'net', using zone configured in 'info', if
* not done already. Update key with new CT state after passing the packet
* through conntrack.
* Note that if the packet is deemed invalid by conntrack, skb->nfct will be
* set to NULL and 0 will be returned.
*/
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.
*/
bool cached = skb_nfct_cached(net, key, info, skb);
enum ip_conntrack_info ctinfo;
struct nf_conn *ct;
if (!cached) {
struct nf_conn *tmpl = info->ct;
int err;
/* 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;
}
/* Repeat if requested, see nf_iterate(). */
do {
err = nf_conntrack_in(net, info->family,
NF_INET_PRE_ROUTING, skb);
} while (err == NF_REPEAT);
if (err != NF_ACCEPT)
return -ENOENT;
/* Clear CT state NAT flags to mark that we have not yet done
* NAT after the nf_conntrack_in() call. We can actually clear
* the whole state, as it will be re-initialized below.
*/
key->ct.state = 0;
/* Update the key, but keep the NAT flags. */
ovs_ct_update_key(skb, info, key, true, true);
}
ct = nf_ct_get(skb, &ctinfo);
if (ct) {
/* Packets starting a new connection must be NATted before the
* helper, so that the helper knows about the NAT. We enforce
* this by delaying both NAT and helper calls for unconfirmed
* connections until the committing CT action. For later
* packets NAT and Helper may be called in either order.
*
* NAT will be done only if the CT action has NAT, and only
* once per packet (per zone), as guarded by the NAT bits in
* the key->ct.state.
*/
if (info->nat && !(key->ct.state & OVS_CS_F_NAT_MASK) &&
(nf_ct_is_confirmed(ct) || info->commit) &&
ovs_ct_nat(net, key, info, skb, ct, ctinfo) != NF_ACCEPT) {
return -EINVAL;
}
/* Userspace may decide to perform a ct lookup without a helper
* specified followed by a (recirculate and) commit with one.
* Therefore, for unconfirmed connections which we will commit,
* we need to attach the helper here.
*/
if (!nf_ct_is_confirmed(ct) && info->commit &&
info->helper && !nfct_help(ct)) {
int err = __nf_ct_try_assign_helper(ct, info->ct,
GFP_ATOMIC);
if (err)
return err;
}
/* Call the helper only if:
* - nf_conntrack_in() was executed above ("!cached") for a
* confirmed connection, or
* - When committing an unconfirmed connection.
*/
if ((nf_ct_is_confirmed(ct) ? !cached : info->commit) &&
ovs_ct_helper(skb, info->family) != NF_ACCEPT) {
return -EINVAL;
}
}
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;
/* If we pass an expected packet through nf_conntrack_in() the
* expectation is typically removed, but the packet could still be
* lost in upcall processing. To prevent this from happening we
* perform an explicit expectation lookup. Expected connections are
* always new, and will be passed through conntrack only when they are
* committed, as it is OK to remove the expectation at that time.
*/
exp = ovs_ct_expect_find(net, &info->zone, info->family, skb);
if (exp) {
u8 state;
/* NOTE: New connections are NATted and Helped only when
* committed, so we are not calling into NAT here.
*/
state = OVS_CS_F_TRACKED | OVS_CS_F_NEW | OVS_CS_F_RELATED;
__ovs_ct_update_key(key, state, &info->zone, exp->master);
} else {
struct nf_conn *ct;
int err;
err = __ovs_ct_lookup(net, key, info, skb);
if (err)
return err;
ct = (struct nf_conn *)skb->nfct;
if (ct)
nf_ct_deliver_cached_events(ct);
}
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;
}
/* 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)
{
int err;
err = __ovs_ct_lookup(net, key, info, skb);
if (err)
return err;
/* Apply changes before confirming the connection so that the initial
* conntrack NEW netlink event carries the values given in the CT
* action.
*/
if (info->mark.mask) {
err = ovs_ct_set_mark(skb, key, info->mark.value,
info->mark.mask);
if (err)
return err;
}
if (labels_nonzero(&info->labels.mask)) {
err = ovs_ct_set_labels(skb, key, &info->labels.value,
&info->labels.mask);
if (err)
return err;
}
/* This will take care of sending queued events even if the connection
* is already confirmed.
*/
if (nf_conntrack_confirm(skb) != NF_ACCEPT)
return -EINVAL;
return 0;
}
/* 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);
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;
}
#ifdef CONFIG_NF_NAT_NEEDED
static int parse_nat(const struct nlattr *attr,
struct ovs_conntrack_info *info, bool log)
{
struct nlattr *a;
int rem;
bool have_ip_max = false;
bool have_proto_max = false;
bool ip_vers = (info->family == NFPROTO_IPV6);
nla_for_each_nested(a, attr, rem) {
static const int ovs_nat_attr_lens[OVS_NAT_ATTR_MAX + 1][2] = {
[OVS_NAT_ATTR_SRC] = {0, 0},
[OVS_NAT_ATTR_DST] = {0, 0},
[OVS_NAT_ATTR_IP_MIN] = {sizeof(struct in_addr),
sizeof(struct in6_addr)},
[OVS_NAT_ATTR_IP_MAX] = {sizeof(struct in_addr),
sizeof(struct in6_addr)},
[OVS_NAT_ATTR_PROTO_MIN] = {sizeof(u16), sizeof(u16)},
[OVS_NAT_ATTR_PROTO_MAX] = {sizeof(u16), sizeof(u16)},
[OVS_NAT_ATTR_PERSISTENT] = {0, 0},
[OVS_NAT_ATTR_PROTO_HASH] = {0, 0},
[OVS_NAT_ATTR_PROTO_RANDOM] = {0, 0},
};
int type = nla_type(a);
if (type > OVS_NAT_ATTR_MAX) {
OVS_NLERR(log,
"Unknown NAT attribute (type=%d, max=%d).\n",
type, OVS_NAT_ATTR_MAX);
return -EINVAL;
}
if (nla_len(a) != ovs_nat_attr_lens[type][ip_vers]) {
OVS_NLERR(log,
"NAT attribute type %d has unexpected length (%d != %d).\n",
type, nla_len(a),
ovs_nat_attr_lens[type][ip_vers]);
return -EINVAL;
}
switch (type) {
case OVS_NAT_ATTR_SRC:
case OVS_NAT_ATTR_DST:
if (info->nat) {
OVS_NLERR(log,
"Only one type of NAT may be specified.\n"
);
return -ERANGE;
}
info->nat |= OVS_CT_NAT;
info->nat |= ((type == OVS_NAT_ATTR_SRC)
? OVS_CT_SRC_NAT : OVS_CT_DST_NAT);
break;
case OVS_NAT_ATTR_IP_MIN:
nla_memcpy(&info->range.min_addr, a,
sizeof(info->range.min_addr));
info->range.flags |= NF_NAT_RANGE_MAP_IPS;
break;
case OVS_NAT_ATTR_IP_MAX:
have_ip_max = true;
nla_memcpy(&info->range.max_addr, a,
sizeof(info->range.max_addr));
info->range.flags |= NF_NAT_RANGE_MAP_IPS;
break;
case OVS_NAT_ATTR_PROTO_MIN:
info->range.min_proto.all = htons(nla_get_u16(a));
info->range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
break;
case OVS_NAT_ATTR_PROTO_MAX:
have_proto_max = true;
info->range.max_proto.all = htons(nla_get_u16(a));
info->range.flags |= NF_NAT_RANGE_PROTO_SPECIFIED;
break;
case OVS_NAT_ATTR_PERSISTENT:
info->range.flags |= NF_NAT_RANGE_PERSISTENT;
break;
case OVS_NAT_ATTR_PROTO_HASH:
info->range.flags |= NF_NAT_RANGE_PROTO_RANDOM;
break;
case OVS_NAT_ATTR_PROTO_RANDOM:
info->range.flags |= NF_NAT_RANGE_PROTO_RANDOM_FULLY;
break;
default:
OVS_NLERR(log, "Unknown nat attribute (%d).\n", type);
return -EINVAL;
}
}
if (rem > 0) {
OVS_NLERR(log, "NAT attribute has %d unknown bytes.\n", rem);
return -EINVAL;
}
if (!info->nat) {
/* Do not allow flags if no type is given. */
if (info->range.flags) {
OVS_NLERR(log,
"NAT flags may be given only when NAT range (SRC or DST) is also specified.\n"
);
return -EINVAL;
}
info->nat = OVS_CT_NAT; /* NAT existing connections. */
} else if (!info->commit) {
OVS_NLERR(log,
"NAT attributes may be specified only when CT COMMIT flag is also specified.\n"
);
return -EINVAL;
}
/* Allow missing IP_MAX. */
if (info->range.flags & NF_NAT_RANGE_MAP_IPS && !have_ip_max) {
memcpy(&info->range.max_addr, &info->range.min_addr,
sizeof(info->range.max_addr));
}
/* Allow missing PROTO_MAX. */
if (info->range.flags & NF_NAT_RANGE_PROTO_SPECIFIED &&
!have_proto_max) {
info->range.max_proto.all = info->range.min_proto.all;
}
return 0;
}
#endif
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 },
#ifdef CONFIG_NF_NAT_NEEDED
/* NAT length is checked when parsing the nested attributes. */
[OVS_CT_ATTR_NAT] = { .minlen = 0, .maxlen = INT_MAX },
#endif
};
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;
#ifdef CONFIG_NF_NAT_NEEDED
case OVS_CT_ATTR_NAT: {
int err = parse_nat(a, info, log);
if (err)
return err;
break;
}
#endif
default:
OVS_NLERR(log, "Unknown conntrack attr (%d)",
type);
return -EINVAL;
}
}
#ifdef CONFIG_NF_CONNTRACK_MARK
if (!info->commit && info->mark.mask) {
OVS_NLERR(log,
"Setting conntrack mark requires 'commit' flag.");
return -EINVAL;
}
#endif
#ifdef CONFIG_NF_CONNTRACK_LABELS
if (!info->commit && labels_nonzero(&info->labels.mask)) {
OVS_NLERR(log,
"Setting conntrack labels requires 'commit' flag.");
return -EINVAL;
}
#endif
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;
}
#ifdef CONFIG_NF_NAT_NEEDED
static bool ovs_ct_nat_to_attr(const struct ovs_conntrack_info *info,
struct sk_buff *skb)
{
struct nlattr *start;
start = nla_nest_start(skb, OVS_CT_ATTR_NAT);
if (!start)
return false;
if (info->nat & OVS_CT_SRC_NAT) {
if (nla_put_flag(skb, OVS_NAT_ATTR_SRC))
return false;
} else if (info->nat & OVS_CT_DST_NAT) {
if (nla_put_flag(skb, OVS_NAT_ATTR_DST))
return false;
} else {
goto out;
}
if (info->range.flags & NF_NAT_RANGE_MAP_IPS) {
if (IS_ENABLED(CONFIG_NF_NAT_IPV4) &&
info->family == NFPROTO_IPV4) {
if (nla_put_in_addr(skb, OVS_NAT_ATTR_IP_MIN,
info->range.min_addr.ip) ||
(info->range.max_addr.ip
!= info->range.min_addr.ip &&
(nla_put_in_addr(skb, OVS_NAT_ATTR_IP_MAX,
info->range.max_addr.ip))))
return false;
} else if (IS_ENABLED(CONFIG_NF_NAT_IPV6) &&
info->family == NFPROTO_IPV6) {
if (nla_put_in6_addr(skb, OVS_NAT_ATTR_IP_MIN,
&info->range.min_addr.in6) ||
(memcmp(&info->range.max_addr.in6,
&info->range.min_addr.in6,
sizeof(info->range.max_addr.in6)) &&
(nla_put_in6_addr(skb, OVS_NAT_ATTR_IP_MAX,
&info->range.max_addr.in6))))
return false;
} else {
return false;
}
}
if (info->range.flags & NF_NAT_RANGE_PROTO_SPECIFIED &&
(nla_put_u16(skb, OVS_NAT_ATTR_PROTO_MIN,
ntohs(info->range.min_proto.all)) ||
(info->range.max_proto.all != info->range.min_proto.all &&
nla_put_u16(skb, OVS_NAT_ATTR_PROTO_MAX,
ntohs(info->range.max_proto.all)))))
return false;
if (info->range.flags & NF_NAT_RANGE_PERSISTENT &&
nla_put_flag(skb, OVS_NAT_ATTR_PERSISTENT))
return false;
if (info->range.flags & NF_NAT_RANGE_PROTO_RANDOM &&
nla_put_flag(skb, OVS_NAT_ATTR_PROTO_HASH))
return false;
if (info->range.flags & NF_NAT_RANGE_PROTO_RANDOM_FULLY &&
nla_put_flag(skb, OVS_NAT_ATTR_PROTO_RANDOM))
return false;
out:
nla_nest_end(skb, start);
return true;
}
#endif
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;
}
#ifdef CONFIG_NF_NAT_NEEDED
if (ct_info->nat && !ovs_ct_nat_to_attr(ct_info, skb))
return -EMSGSIZE;
#endif
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 - 1)) {
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);
}
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