The introduction of TCP_NEW_SYN_RECV state, and the addition of request
sockets to the ehash table seems to have broken the --transparent option
of the socket match for IPv6 (around commit a9407000).

Now that the socket lookup finds the TCP_NEW_SYN_RECV socket instead of the
listener, the --transparent option tries to match on the no_srccheck flag
of the request socket.

Unfortunately, that flag was only set for IPv4 sockets in tcp_v4_init_req()
by copying the transparent flag of the listener socket. This effectively
causes '-m socket --transparent' not match on the ACK packet sent by the
client in a TCP handshake.

Based on the suggestion from Eric Dumazet, this change moves the code
initializing no_srccheck to tcp_conn_request(), rendering the above
scenario working again.

Fixes: a9407000 ("netfilter: xt_socket: prepare for TCP_NEW_SYN_RECV support")
Signed-off-by: NAlex Badics <alex.badics@balabit.com>
Signed-off-by: NKOVACS Krisztian <hidden@balabit.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Fabian reports a possible conntrack memory leak (could not reproduce so
far), however, one minor issue can be easily resolved:

> cat /proc/net/nf_conntrack | wc -l = 5
> 4 minutes required to clean up the table.

We should not report those timed-out entries to the user in first place.
And instead of just skipping those timed-out entries while iterating over
the table we can also zap them (we already do this during ctnetlink
walks, but I forgot about the /proc interface).

Fixes: f330a7fd ("netfilter: conntrack: get rid of conntrack timer")
Reported-by: NFabian Frederick <fabf@skynet.be>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Create a new revision for the hashlimit iptables extension module. Rev 2
will support higher pps of upto 1 million, Version 1 supports only 10k.

To support this we have to increase the size of the variables avg and
burst in hashlimit_cfg to 64-bit. Create two new structs hashlimit_cfg2
and xt_hashlimit_mtinfo2 and also create newer versions of all the
functions for match, checkentry and destroy.

Some of the functions like hashlimit_mt, hashlimit_mt_check etc are very
similar in both rev1 and rev2 with only minor changes, so I have split
those functions and moved all the common code to a *_common function.
Signed-off-by: NVishwanath Pai <vpai@akamai.com>
Signed-off-by: NJoshua Hunt <johunt@akamai.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

I am planning to add a revision 2 for the hashlimit xtables module to
support higher packets per second rates. This patch renames all the
functions and variables related to revision 1 by adding _v1 at the
end of the names.
Signed-off-by: NVishwanath Pai <vpai@akamai.com>
Signed-off-by: NJoshua Hunt <johunt@akamai.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

NFT_CT_MARK is unrelated to direction, so if NFTA_CT_DIRECTION attr is
specified, report EINVAL to the userspace. This validation check was
already done at nft_ct_get_init, but we missed it in nft_ct_set_init.
Signed-off-by: NLiping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Currently, if the user want to match ct l3proto, we must specify the
direction, for example:
  # nft add rule filter input ct original l3proto ipv4
                                 ^^^^^^^^
Otherwise, error message will be reported:
  # nft add rule filter input ct l3proto ipv4
  nft add rule filter input ct l3proto ipv4
  <cmdline>:1:1-38: Error: Could not process rule: Invalid argument
  add rule filter input ct l3proto ipv4
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Actually, there's no need to require NFTA_CT_DIRECTION attr, because
ct l3proto and protocol are unrelated to direction.

And for compatibility, even if the user specify the NFTA_CT_DIRECTION
attr, do not report error, just skip it.
Signed-off-by: NLiping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

It is valid that the TCP RST packet which does not set ack flag, and bytes
of ack number are zero. But current seqadj codes would adjust the "0" ack
to invalid ack number. Actually seqadj need to check the ack flag before
adjust it for these RST packets.

The following is my test case

client is 10.26.98.245, and add one iptable rule:
iptables  -I INPUT -p tcp --sport 12345 -m connbytes --connbytes 2:
--connbytes-dir reply --connbytes-mode packets -j REJECT --reject-with
tcp-reset
This iptables rule could generate on TCP RST without ack flag.

server:10.172.135.55
Enable the synproxy with seqadjust by the following iptables rules
iptables -t raw -A PREROUTING -i eth0 -p tcp -d 10.172.135.55 --dport 12345
-m tcp --syn -j CT --notrack

iptables -A INPUT -i eth0 -p tcp -d 10.172.135.55 --dport 12345 -m conntrack
--ctstate INVALID,UNTRACKED -j SYNPROXY --sack-perm --timestamp --wscale 7
--mss 1460
iptables -A OUTPUT -o eth0 -p tcp -s 10.172.135.55 --sport 12345 -m conntrack
--ctstate INVALID,UNTRACKED -m tcp --tcp-flags SYN,RST,ACK SYN,ACK -j ACCEPT

The following is my test result.

1. packet trace on client
root@routers:/tmp# tcpdump -i eth0 tcp port 12345 -n
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on eth0, link-type EN10MB (Ethernet), capture size 65535 bytes
IP 10.26.98.245.45154 > 10.172.135.55.12345: Flags [S], seq 3695959829,
win 29200, options [mss 1460,sackOK,TS val 452367884 ecr 0,nop,wscale 7],
length 0
IP 10.172.135.55.12345 > 10.26.98.245.45154: Flags [S.], seq 546723266,
ack 3695959830, win 0, options [mss 1460,sackOK,TS val 15643479 ecr 452367884,
nop,wscale 7], length 0
IP 10.26.98.245.45154 > 10.172.135.55.12345: Flags [.], ack 1, win 229,
options [nop,nop,TS val 452367885 ecr 15643479], length 0
IP 10.172.135.55.12345 > 10.26.98.245.45154: Flags [.], ack 1, win 226,
options [nop,nop,TS val 15643479 ecr 452367885], length 0
IP 10.26.98.245.45154 > 10.172.135.55.12345: Flags [R], seq 3695959830,
win 0, length 0

2. seqadj log on server
[62873.867319] Adjusting sequence number from 602341895->546723267,
ack from 3695959830->3695959830
[62873.867644] Adjusting sequence number from 602341895->546723267,
ack from 3695959830->3695959830
[62873.869040] Adjusting sequence number from 3695959830->3695959830,
ack from 0->55618628

To summarize, it is clear that the seqadj codes adjust the 0 ack when receive
one TCP RST packet without ack.
Signed-off-by: NGao Feng <fgao@ikuai8.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

The netfilter hook list never uses the prev pointer, and so can be trimmed to
be a simple singly-linked list.

In addition to having a more light weight structure for hook traversal,
struct net becomes 5568 bytes (down from 6400) and struct net_device becomes
2176 bytes (down from 2240).
Signed-off-by: NAaron Conole <aconole@bytheb.org>
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

A future patch will modify the hook drop and outfn functions.  This will
cause the line lengths to take up too much space.  This is simply a
readability change.
Signed-off-by: NAaron Conole <aconole@bytheb.org>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This commit adds an upfront check for sane values to be passed when
registering a netfilter hook.  This will be used in a future patch for a
simplified hook list traversal.
Signed-off-by: NAaron Conole <aconole@bytheb.org>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

All of the callers of nf_hook_slow already hold the rcu_read_lock, so this
cleanup removes the recursive call.  This is just a cleanup, as the locking
code gracefully handles this situation.
Signed-off-by: NAaron Conole <aconole@bytheb.org>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This commit ensures that the rcu read-side lock is held while the
ingress hook is called.  This ensures that a call to nf_hook_slow (and
ultimately nf_ingress) will be read protected.
Signed-off-by: NAaron Conole <aconole@bytheb.org>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This makes things simpler because we can store the head of the list
in the nf_state structure without worrying about concurrent add/delete
of hook elements from the list.

A future commit will make use of this to implement a simpler
linked-list.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NAaron Conole <aconole@bytheb.org>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This replaces the last uses of NF_HOOK_THRESH().
Followup patch will remove it and rename nf_hook_thresh.

The reason is that inet (non-bridge) netfilter no longer invokes the
hooks from hooks, so we do no longer need the thresh value to skip hooks
with a lower priority.

The bridge netfilter however may need to do this. br_nf_hook_thresh is a
wrapper that is supposed to do this, i.e. only call hooks with a
priority that exceeds NF_BR_PRI_BRNF.

It's used only in the recursion cases of br_netfilter.  It invokes
nf_hook_slow while holding an rcu read-side critical section to make a
future cleanup simpler.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NAaron Conole <aconole@bytheb.org>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

The origin codes perform two condition checks with dst_mtu(skb_dst(skb))
and in_mtu. And the last statement is "min(dst_mtu(skb_dst(skb)),
in_mtu) - minlen". It may let reader think about how about the result.
Would it be negative.

Now assign the result of min(dst_mtu(skb_dst(skb)), in_mtu) to a new
variable, then only perform one condition check, and it is more readable.
Signed-off-by: NGao Feng <fgao@ikuai8.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

We already checked for !found just a bit before:

        if (!found) {
                regs->verdict.code = NFT_BREAK;
                return;
        }

        if (found && set->flags & NFT_SET_MAP)
            ^^^^^

So this redundant check can just go away.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

It's better to use sizeof(info->name)-1 as index to force set the string
tail instead of literal number '29'.
Signed-off-by: NGao Feng <fgao@ikuai8.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

There are some codes which are used to get one random once in netfilter.
We could use net_get_random_once to simplify these codes.
Signed-off-by: NGao Feng <fgao@ikuai8.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

pkt->xt.thoff is not always set properly, but we use it without any check.
For payload expr, it will cause wrong results. For nftrace, we may notify
the wrong network or transport header to the user space, furthermore,
input the following nft rules, warning message will be printed out:
  # nft add rule arp filter output meta nftrace set 1

  WARNING: CPU: 0 PID: 13428 at net/netfilter/nf_tables_trace.c:263
  nft_trace_notify+0x4a3/0x5e0 [nf_tables]
  Call Trace:
  [<ffffffff813d58ae>] dump_stack+0x63/0x85
  [<ffffffff810a4c0b>] __warn+0xcb/0xf0
  [<ffffffff810a4d3d>] warn_slowpath_null+0x1d/0x20
  [<ffffffffa0589703>] nft_trace_notify+0x4a3/0x5e0 [nf_tables]
  [ ... ]
  [<ffffffffa05690a8>] nft_do_chain_arp+0x78/0x90 [nf_tables_arp]
  [<ffffffff816f4aa2>] nf_iterate+0x62/0x80
  [<ffffffff816f4b33>] nf_hook_slow+0x73/0xd0
  [<ffffffff81732bbf>] arp_xmit+0x8f/0xb0
  [ ... ]
  [<ffffffff81732d36>] arp_solicit+0x106/0x2c0

So before we use pkt->xt.thoff, check the tprot_set first.
Signed-off-by: NLiping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

There's an off-by-one issue in nft_payload_fast_eval, skb_tail_pointer
and ptr + priv->len all point to the last valid address plus 1. So if
they are equal, we can still fetch the valid data. It's unnecessary to
fall back to nft_payload_eval.
Signed-off-by: NLiping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

After commit ac286344 ("netfilter: bridge: add nf_afinfo to enable
queuing to userspace"), we can queue packets to the user space in bridge
family. But when the user specify the queue range, packets will be only
delivered to the first queue num. Because in nfqueue_hash, we only support
ipv4 and ipv6 family. Now add support for bridge family too.
Suggested-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NLiping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Currently, the user can specify the queue numbers by _QUEUE_NUM and
_QUEUE_TOTAL attributes, this is enough in most situations.

But acctually, it is not very flexible, for example:
  tcp dport 80 mapped to queue0
  tcp dport 81 mapped to queue1
  tcp dport 82 mapped to queue2
In order to do this thing, we must add 3 nft rules, and more
mapping meant more rules ...

So take one register to select the queue number, then we can add one
simple rule to mapping queues, maybe like this:
  queue num tcp dport map { 80:0, 81:1, 82:2 ... }

Florian Westphal also proposed wider usage scenarios:
  queue num jhash ip saddr . ip daddr mod ...
  queue num meta cpu ...
  queue num meta mark ...

The last point is how to load a queue number from sreg, although we can
use *(u16*)&regs->data[reg] to load the queue number, just like nat expr
to load its l4port do.

But we will cooperate with hash expr, meta cpu, meta mark expr and so on.
They all store the result to u32 type, so cast it to u16 pointer and
dereference it will generate wrong result in the big endian system.

So just keep it simple, we treat queue number as u32 type, although u16
type is already enough.
Suggested-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NLiping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Fetch value and validate u32 netlink attribute. This validation is
usually required when the u32 netlink attributes are being stored in a
field whose size is smaller.

This patch revisits 4da449ae ("netfilter: nft_exthdr: Add size check
on u8 nft_exthdr attributes").

Fixes: 96518518 ("netfilter: add nftables")
Suggested-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NLaura Garcia Liebana <nevola@gmail.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Add support of an offset value for incremental counter and random. With
this option the sysadmin is able to start the counter to a certain value
and then apply the generated number.

Example:

	meta mark set numgen inc mod 2 offset 100

This will generate marks with the serie 100, 101, 100, 101, ...
Suggested-by: NPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: NLaura Garcia Liebana <nevola@gmail.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

The overflow validation in the init() function establishes that the
maximum value that the hash could reach is less than U32_MAX, which is
likely to be true.

The fix detects the overflow when the maximum hash value is less than
the offset itself.

Fixes: 70ca767e ("netfilter: nft_hash: Add hash offset value")
Reported-by: NLiping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: NLaura Garcia Liebana <nevola@gmail.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

After we generate a new number, we still use the priv->counter and
store it to the dreg. This is not correct, another cpu may already
change it to a new number. So we must use the generated number, not
the priv->counter itself.

Fixes: 91dbc6be ("netfilter: nf_tables: add number generator expression")
Signed-off-by: NLiping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

These counters sit in hot path and do show up in perf, this is especially
true for 'found' and 'searched' which get incremented for every packet
processed.

Information like

searched=212030105
new=623431
found=333613
delete=623327

does not seem too helpful nowadays:

- on busy systems found and searched will overflow every few hours
(these are 32bit integers), other more busy ones every few days.

- for debugging there are better methods, such as iptables' trace target,
the conntrack log sysctls.  Nowadays we also have perf tool.

This removes packet path stat counters except those that
are expected to be 0 (or close to 0) on a normal system, e.g.
'insert_failed' (race happened) or 'invalid' (proto tracker rejects).

The insert stat is retained for the ctnetlink case.
The found stat is retained for the tuple-is-taken check when NAT has to
determine if it needs to pick a different source address.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

hash_v6 is used by both nftables and ip6tables, so depend on
IP6_NF_IPTABLES is not properly.

Actually, it only parses ipv6hdr and computes a hash value, so
even if IPV6 is disabled, there's no side effect too, remove it.
Signed-off-by: NLiping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

There are some codes of netfilter module which did not check the return
value of nft_register_chain_type. Add the checks now.
Signed-off-by: NGao Feng <fgao@ikuai8.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

There are some codes of netfilter module which did not check the return
value of register_netdevice_notifier. Add the checks now.
Signed-off-by: NGao Feng <fgao@ikuai8.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Instead of several goto's just to return the result, simply return it.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This is overly conservative and not flexible at all, so better let them
go through and let the filtering policy decide what to do with them. We
use skb_header_pointer() all over the place so we would just fail to
match when trying to access fields from malformed traffic.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Consolidate pktinfo setup and validation by using the new generic
functions so we converge to the netdev family codebase.

We only need a linear IPv4 and IPv6 header from the reject expression,
so move nft_bridge_iphdr_validate() and nft_bridge_ip6hdr_validate()
to net/bridge/netfilter/nft_reject_bridge.c.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

These functions are extracted from the netdev family, they initialize
the pktinfo structure and validate that the IPv4 and IPv6 headers are
well-formed given that these functions are called from a path where
layer 3 sanitization did not happen yet.

These functions are placed in include/net/netfilter/nf_tables_ipv{4,6}.h
so they can be reused by a follow up patch to use them from the bridge
family too.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Make sure the pktinfo protocol fields are initialized if this fails to
parse the transport header.
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

This patch introduces nft_set_pktinfo_unspec() that ensures proper
initialization all of pktinfo fields for non-IP traffic. This is used
by the bridge, netdev and arp families.

This new function relies on nft_set_pktinfo_proto_unspec() to set a new
tprot_set field that indicates if transport protocol information is
available. Remain fields are zeroed.

The meta expression has been also updated to check to tprot_set in first
place given that zero is a valid tprot value. Even a handcrafted packet
may come with the IPPROTO_RAW (255) protocol number so we can't rely on
this value as tprot unset.
Reported-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

The dynset expression matches if we can fit a new entry into the set.
If there is no room for it, then it breaks the rule evaluation.

This patch introduces the inversion flag so you can add rules to
explicitly drop packets that don't fit into the set. For example:

 # nft filter input flow table xyz size 4 { ip saddr timeout 120s counter } overflow drop

This is useful to provide a replacement for connlimit.

For the rule above, every new entry uses the IPv4 address as key in the
set, this entry gets a timeout of 120 seconds that gets refresh on every
packet seen. If we get new flow and our set already contains 4 entries
already, then this packet is dropped.

You can already express this in positive logic, assuming default policy
to drop:

 # nft filter input flow table xyz size 4 { ip saddr timeout 10s counter } accept
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Add support to pass through an offset to the hash value. With this
feature, the sysadmin is able to generate a hash with a given
offset value.

Example:

	meta mark set jhash ip saddr mod 2 seed 0xabcd offset 100

This option generates marks according to the source address from 100 to
101.
Signed-off-by: NLaura Garcia Liebana <nevola@gmail.com>

After commit adf05168 ("netfilter: remove ip_conntrack* sysctl
compat code"), ctl_table_path member in struct nf_conntrack_l3proto{}
is not used anymore, remove it.
Signed-off-by: NLiping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

Although the validation of queues_total and queuenum is checked in nft
utility, but user can add nft rules via nfnetlink, so it is necessary
to check the validation at the nft_queue expr init routine too.

Tested by run ./nft-test.py any/queue.t:
  any/queue.t: 6 unit tests, 0 error, 0 warning
Signed-off-by: NLiping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>