Fix blank line coding style issues, make the code cleaner.
Remove a redundant blank line in ip_rcv_core().
Insert a blank line in ip_rcv() between different statement blocks.
Signed-off-by: Yang Wei <yang.wei9@zte.com.cn>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
In certain cases, pskb_trim_rcsum() may change skb pointers.
Reinitialize header pointers afterwards to avoid potential
use-after-frees. Add a note in the documentation of
pskb_trim_rcsum(). Found by KASAN.
Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Several conflicts, seemingly all over the place.
I used Stephen Rothwell's sample resolutions for many of these, if not
just to double check my own work, so definitely the credit largely
goes to him.
The NFP conflict consisted of a bug fix (moving operations
past the rhashtable operation) while chaning the initial
argument in the function call in the moved code.
The net/dsa/master.c conflict had to do with a bug fix intermixing of
making dsa_master_set_mtu() static with the fixing of the tagging
attribute location.
cls_flower had a conflict because the dup reject fix from Or
overlapped with the addition of port range classifiction.
__set_phy_supported()'s conflict was relatively easy to resolve
because Andrew fixed it in both trees, so it was just a matter
of taking the net-next copy. Or at least I think it was :-)
Joe Stringer's fix to the handling of netns id 0 in bpf_sk_lookup()
intermixed with changes on how the sdif and caller_net are calculated
in these code paths in net-next.
The remaining BPF conflicts were largely about the addition of the
__bpf_md_ptr stuff in 'net' overlapping with adjustments and additions
to the relevant data structure where the MD pointer macros are used.
Signed-off-by: David S. Miller <davem@davemloft.net>
So that we can re-use it at the UDP level in a later patch
rfc v3 -> v1
- add the helper declaration into the ip header
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It documents what is happening, and eliminates the spurious list
pointer poisoning.
In the long term, in order to get proper list head debugging, we
might want to use the list poison value as the indicator that
an SKB is a singleton and not on a list.
Signed-off-by: David S. Miller <davem@davemloft.net>
An SKB is not on a list if skb->next is NULL.
Codify this convention into a helper function and use it
where we are dequeueing an SKB and need to mark it as such.
Signed-off-by: David S. Miller <davem@davemloft.net>
In commit 5fa12739a5 ("net: ipv4: listify ip_rcv_finish") calling
dst_input(skb) was split-out. The ip_sublist_rcv_finish() just calls
dst_input(skb) in a loop.
The problem is that ip_sublist_rcv_finish() forgot to remove the SKB
from the list before invoking dst_input(). Further more we need to
clear skb->next as other parts of the network stack use another kind
of SKB lists for xmit_more (see dev_hard_start_xmit).
A crash occurs if e.g. dst_input() invoke ip_forward(), which calls
dst_output()/ip_output() that eventually calls __dev_queue_xmit() +
sch_direct_xmit(), and a crash occurs in validate_xmit_skb_list().
This patch only fixes the crash, but there is a huge potential for
a performance boost if we can pass an SKB-list through to ip_forward.
Fixes: 5fa12739a5 ("net: ipv4: listify ip_rcv_finish")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
If we have an L3 master device, l3mdev_ip_rcv() will steal the skb, but
we were returning NET_RX_SUCCESS from ip_rcv_finish_core() which meant
that ip_list_rcv_finish() would keep it on the list. Instead let's
move the l3mdev_ip_rcv() call into the caller, so that our response to
a steal can be different in the single packet path (return
NET_RX_SUCCESS) and the list path (forget this packet and continue).
Fixes: 5fa12739a5 ("net: ipv4: listify ip_rcv_finish")
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Since callees (ip_rcv_core() and ip_rcv_finish_core()) might free or steal
the skb, we can't use the list_cut_before() method; we can't even do a
list_del(&skb->list) in the drop case, because skb might have already been
freed and reused.
So instead, take each skb off the source list before processing, and add it
to the sublist afterwards if it wasn't freed or stolen.
Fixes: 5fa12739a5 net: ipv4: listify ip_rcv_finish
Fixes: 17266ee939 net: ipv4: listified version of ip_rcv
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
ip_rcv_finish_core(), if it does not drop, sets skb->dst by either early
demux or route lookup. The last step, calling dst_input(skb), is left to
the caller; in the listified case, we split to form sublists with a common
dst, but then ip_sublist_rcv_finish() just calls dst_input(skb) in a loop.
The next step in listification would thus be to add a list_input() method
to struct dst_entry.
Early demux is an indirect call based on iph->protocol; this is another
opportunity for listification which is not taken here (it would require
slicing up ip_rcv_finish_core() to allow splitting on protocol changes).
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Also involved adding a way to run a netfilter hook over a list of packets.
Rather than attempting to make netfilter know about lists (which would be
a major project in itself) we just let it call the regular okfn (in this
case ip_rcv_finish()) for any packets it steals, and have it give us back
a list of packets it's synchronously accepted (which normally NF_HOOK
would automatically call okfn() on, but we want to be able to potentially
pass the list to a listified version of okfn().)
The netfilter hooks themselves are indirect calls that still happen per-
packet (see nf_hook_entry_hookfn()), but again, changing that can be left
for future work.
There is potential for out-of-order receives if the netfilter hook ends up
synchronously stealing packets, as they will be processed before any
accepts earlier in the list. However, it was already possible for an
asynchronous accept to cause out-of-order receives, so presumably this is
considered OK.
Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is optimization, which makes ip_call_ra_chain()
iterate less sockets to find the sockets it's looking for.
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently no error is emitted, but this infrastructure will
used by the next patch to allow source address validation
for mcast sockets.
Since early demux can do a route lookup and an ipv4 route
lookup can return an error code this is consistent with the
current ipv4 route infrastructure.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Certain system process significant unconnected UDP workload.
It would be preferrable to disable UDP early demux for those systems
and enable it for TCP only.
By disabling UDP demux, we see these slight gains on an ARM64 system-
782 -> 788Mbps unconnected single stream UDPv4
633 -> 654Mbps unconnected UDPv4 different sources
The performance impact can change based on CPU architecure and cache
sizes. There will not much difference seen if entire UDP hash table
is in cache.
Both sysctls are enabled by default to preserve existing behavior.
v1->v2: Change function pointer instead of adding conditional as
suggested by Stephen.
v2->v3: Read once in callers to avoid issues due to compiler
optimizations. Also update commit message with the tests.
v3->v4: Store and use read once result instead of querying pointer
again incorrectly.
v4->v5: Refactor to avoid errors due to compilation with IPV6={m,n}
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Suggested-by: Eric Dumazet <edumazet@google.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Cc: Tom Herbert <tom@herbertland.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
The function ip_rcv_finish() calls l3mdev_ip_rcv(). On any VRF except
the global VRF, this replaces skb->dev with the VRF master interface.
When calling ip_route_input_noref() from here, the checks for forwarding
look at this master device instead of the initial ingress interface.
This will allow packets to be routed which normally would be dropped.
For example, an interface that is not assigned an IP address should
drop packets, but because the checking is against the master device, the
packet will be forwarded.
The fix here is to still call l3mdev_ip_rcv(), but remember the initial
net_device. This is passed to the other functions within ip_rcv_finish,
so they still see the original interface.
Signed-off-by: Mark Tomlinson <mark.tomlinson@alliedtelesis.co.nz>
Acked-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Applications such as OSPF and BFD need the original ingress device not
the VRF device; the latter can be derived from the former. To that end
add the skb_iif to inet_skb_parm and set it in ipv4 code after clearing
the skb control buffer similar to IPv6. From there the pktinfo can just
pull it from cb with the PKTINFO_SKB_CB cast.
The previous patch moving the skb->dev change to L3 means nothing else
is needed for IPv6; it just works.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently the VRF driver uses the rx_handler to switch the skb device
to the VRF device. Switching the dev prior to the ip / ipv6 layer
means the VRF driver has to duplicate IP/IPv6 processing which adds
overhead and makes features such as retaining the ingress device index
more complicated than necessary.
This patch moves the hook to the L3 layer just after the first NF_HOOK
for PRE_ROUTING. This location makes exposing the original ingress device
trivial (next patch) and allows adding other NF_HOOKs to the VRF driver
in the future.
dev_queue_xmit_nit is exported so that the VRF driver can cycle the skb
with the switched device through the packet taps to maintain current
behavior (tcpdump can be used on either the vrf device or the enslaved
devices).
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rename NET_INC_STATS_BH() to __NET_INC_STATS()
and NET_ADD_STATS_BH() to __NET_ADD_STATS()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rename IP_UPD_PO_STATS_BH() to __IP_UPD_PO_STATS()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Rename IP_INC_STATS_BH() to __IP_INC_STATS(), to
better express this is used in non preemptible context.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In order to solve a problem with 802.11, the so-called hole-196 attack,
add an option (sysctl) called "drop_unicast_in_l2_multicast" which, if
enabled, causes the stack to drop IPv4 unicast packets encapsulated in
link-layer multi- or broadcast frames. Such frames can (as an attack)
be created by any member of the same wireless network and transmitted
as valid encrypted frames since the symmetric key for broadcast frames
is shared between all stations.
Additionally, enabling this option provides compliance with a SHOULD
clause of RFC 1122.
Reviewed-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We should not assume a valid protocol header is present,
as this is not the case for IPv4 fragments.
Lets avoid extra cache line misses and potential bugs
if we actually find a socket and incorrectly uses its dst.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The function ip_defrag is called on both the input and the output
paths of the networking stack. In particular conntrack when it is
tracking outbound packets from the local machine calls ip_defrag.
So add a struct net parameter and stop making ip_defrag guess which
network namespace it needs to defragment packets in.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
ip_call_ra_chain is called early in the forwarding chain from
ip_forward and ip_mr_input, which makes skb->dev the correct
expression to get the input network device and dev_net(skb->dev) a
correct expression for the network namespace the packet is being
processed in.
Compute the network namespace and store it in a variable to make the
code clearer.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is immediately motivated by the bridge code that chains functions that
call into netfilter. Without passing net into the okfns the bridge code would
need to guess about the best expression for the network namespace to process
packets in.
As net is frequently one of the first things computed in continuation functions
after netfilter has done it's job passing in the desired network namespace is in
many cases a code simplification.
To support this change the function dst_output_okfn is introduced to
simplify passing dst_output as an okfn. For the moment dst_output_okfn
just silently drops the struct net.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Pass a network namespace parameter into the netfilter hooks. At the
call site of the netfilter hooks the path a packet is taking through
the network stack is well known which allows the network namespace to
be easily and reliabily.
This allows the replacement of magic code like
"dev_net(state->in?:state->out)" that appears at the start of most
netfilter hooks with "state->net".
In almost all cases the network namespace passed in is derived
from the first network device passed in, guaranteeing those
paths will not see any changes in practice.
The exceptions are:
xfrm/xfrm_output.c:xfrm_output_resume() xs_net(skb_dst(skb)->xfrm)
ipvs/ip_vs_xmit.c:ip_vs_nat_send_or_cont() ip_vs_conn_net(cp)
ipvs/ip_vs_xmit.c:ip_vs_send_or_cont() ip_vs_conn_net(cp)
ipv4/raw.c:raw_send_hdrinc() sock_net(sk)
ipv6/ip6_output.c:ip6_xmit() sock_net(sk)
ipv6/ndisc.c:ndisc_send_skb() dev_net(skb->dev) not dev_net(dst->dev)
ipv6/raw.c:raw6_send_hdrinc() sock_net(sk)
br_netfilter_hooks.c:br_nf_pre_routing_finish() dev_net(skb->dev) before skb->dev is set to nf_bridge->physindev
In all cases these exceptions seem to be a better expression for the
network namespace the packet is being processed in then the historic
"dev_net(in?in:out)". I am documenting them in case something odd
pops up and someone starts trying to track down what happened.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Introduces a new dst_metadata which enables to carry per packet metadata
between forwarding and processing elements via the skb->dst pointer.
The structure is set up to be a union. Thus, each separate type of
metadata requires its own dst instance. If demand arises to carry
multiple types of metadata concurrently, metadata dst entries can be
made stackable.
The metadata dst entry is refcnt'ed as expected for now but a non
reference counted use is possible if the reference is forced before
queueing the skb.
In order to allow allocating dsts with variable length, the existing
dst_alloc() is split into a dst_alloc() and dst_init() function. The
existing dst_init() function to initialize the subsystem is being
renamed to dst_subsys_init() to make it clear what is what.
The check before ip_route_input() is changed to ignore metadata dsts
and drop the dst inside the routing function thus allowing to interpret
metadata in a later commit.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
On the output paths in particular, we have to sometimes deal with two
socket contexts. First, and usually skb->sk, is the local socket that
generated the frame.
And second, is potentially the socket used to control a tunneling
socket, such as one the encapsulates using UDP.
We do not want to disassociate skb->sk when encapsulating in order
to fix this, because that would break socket memory accounting.
The most extreme case where this can cause huge problems is an
AF_PACKET socket transmitting over a vxlan device. We hit code
paths doing checks that assume they are dealing with an ipv4
socket, but are actually operating upon the AF_PACKET one.
Signed-off-by: David S. Miller <davem@davemloft.net>
The ipv4 code uses a mixture of coding styles. In some instances check
for non-NULL pointer is done as x != NULL and sometimes as x. x is
preferred according to checkpatch and this patch makes the code
consistent by adopting the latter form.
No changes detected by objdiff.
Signed-off-by: Ian Morris <ipm@chirality.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
The ipv4 code uses a mixture of coding styles. In some instances check
for NULL pointer is done as x == NULL and sometimes as !x. !x is
preferred according to checkpatch and this patch makes the code
consistent by adopting the latter form.
No changes detected by objdiff.
Signed-off-by: Ian Morris <ipm@chirality.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
I see a memory leak when using a transparent HTTP proxy using TPROXY
together with TCP early demux and Kernel v3.8.13.15 (Ubuntu stable):
unreferenced object 0xffff88008cba4a40 (size 1696):
comm "softirq", pid 0, jiffies 4294944115 (age 8907.520s)
hex dump (first 32 bytes):
0a e0 20 6a 40 04 1b 37 92 be 32 e2 e8 b4 00 00 .. j@..7..2.....
02 00 07 01 00 00 00 00 00 00 00 00 00 00 00 00 ................
backtrace:
[<ffffffff810b710a>] kmem_cache_alloc+0xad/0xb9
[<ffffffff81270185>] sk_prot_alloc+0x29/0xc5
[<ffffffff812702cf>] sk_clone_lock+0x14/0x283
[<ffffffff812aaf3a>] inet_csk_clone_lock+0xf/0x7b
[<ffffffff8129a893>] netlink_broadcast+0x14/0x16
[<ffffffff812c1573>] tcp_create_openreq_child+0x1b/0x4c3
[<ffffffff812c033e>] tcp_v4_syn_recv_sock+0x38/0x25d
[<ffffffff812c13e4>] tcp_check_req+0x25c/0x3d0
[<ffffffff812bf87a>] tcp_v4_do_rcv+0x287/0x40e
[<ffffffff812a08a7>] ip_route_input_noref+0x843/0xa55
[<ffffffff812bfeca>] tcp_v4_rcv+0x4c9/0x725
[<ffffffff812a26f4>] ip_local_deliver_finish+0xe9/0x154
[<ffffffff8127a927>] __netif_receive_skb+0x4b2/0x514
[<ffffffff8127aa77>] process_backlog+0xee/0x1c5
[<ffffffff8127c949>] net_rx_action+0xa7/0x200
[<ffffffff81209d86>] add_interrupt_randomness+0x39/0x157
But there are many more, resulting in the machine going OOM after some
days.
From looking at the TPROXY code, and with help from Florian, I see
that the memory leak is introduced in tcp_v4_early_demux():
void tcp_v4_early_demux(struct sk_buff *skb)
{
/* ... */
iph = ip_hdr(skb);
th = tcp_hdr(skb);
if (th->doff < sizeof(struct tcphdr) / 4)
return;
sk = __inet_lookup_established(dev_net(skb->dev), &tcp_hashinfo,
iph->saddr, th->source,
iph->daddr, ntohs(th->dest),
skb->skb_iif);
if (sk) {
skb->sk = sk;
where the socket is assigned unconditionally to skb->sk, also bumping
the refcnt on it. This is problematic, because in our case the skb
has already a socket assigned in the TPROXY target. This then results
in the leak I see.
The very same issue seems to be with IPv6, but haven't tested.
Reviewed-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Holger Eitzenberger <holger@eitzenberger.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
With GRO/LRO processing, there is a problem because Ip[6]InReceives SNMP
counters do not count the number of frames, but number of aggregated
segments.
Its probably too late to change this now.
This patch adds four new counters, tracking number of frames, regardless
of LRO/GRO, and on a per ECN status basis, for IPv4 and IPv6.
Ip[6]NoECTPkts : Number of packets received with NOECT
Ip[6]ECT1Pkts : Number of packets received with ECT(1)
Ip[6]ECT0Pkts : Number of packets received with ECT(0)
Ip[6]CEPkts : Number of packets received with Congestion Experienced
lph37:~# nstat | egrep "Pkts|InReceive"
IpInReceives 1634137 0.0
Ip6InReceives 3714107 0.0
Ip6InNoECTPkts 19205 0.0
Ip6InECT0Pkts 52651828 0.0
IpExtInNoECTPkts 33630 0.0
IpExtInECT0Pkts 15581379 0.0
IpExtInCEPkts 6 0.0
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
commit 45f00f99d6 ("ipv4: tcp: clean up tcp_v4_early_demux()") added a
performance regression for non GRO traffic, basically disabling
IP early demux.
IPv6 stack resets transport header in ip6_rcv() before calling
IP early demux in ip6_rcv_finish(), while IPv4 does this only in
ip_local_deliver_finish(), _after_ IP early demux.
GRO traffic happened to enable IP early demux because transport header
is also set in inet_gro_receive()
Instead of reverting the faulty commit, we can make IPv4/IPv6 behave the
same : transport_header should be set in ip_rcv() instead of
ip_local_deliver_finish()
ip_local_deliver_finish() can also use skb_network_header_len() which is
faster than ip_hdrlen()
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Neal Cardwell <ncardwell@google.com>
Cc: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add MIB counters for checksum errors in IP layer,
and TCP/UDP/ICMP layers, to help diagnose problems.
$ nstat -a | grep Csum
IcmpInCsumErrors 72 0.0
TcpInCsumErrors 382 0.0
UdpInCsumErrors 463221 0.0
Icmp6InCsumErrors 75 0.0
Udp6InCsumErrors 173442 0.0
IpExtInCsumErrors 10884 0.0
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
I had a report recently of a user trying to use dropwatch to localise some frame
loss, and they were getting false positives. Turned out they were using a user
space SCTP stack that used raw sockets to grab frames. When we don't have a
registered protocol for a given packet, we record it as a drop, even if a raw
socket receieves the frame. We should only record the drop in the event a raw
socket doesnt exist to receive the frames
Tested by the reported successfully
Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Reported-by: William Reich <reich@ulticom.com>
Tested-by: William Reich <reich@ulticom.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: William Reich <reich@ulticom.com>
CC: eric.dumazet@gmail.com
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
All in-tree ipv4 protocol implementations are now namespace
aware. Therefore all the run-time checks are superfluous.
Reject registry of any non-namespace aware ipv4 protocol.
Eventually we'll remove prot->netns_ok and this registry
time check as well.
Signed-off-by: David S. Miller <davem@davemloft.net>
early_demux() handlers should be called in RCU context, and as we
use skb_dst_set_noref(skb, dst), caller must not exit from RCU context
before dst use (skb_dst(skb)) or release (skb_drop(dst))
Therefore, rcu_read_lock()/rcu_read_unlock() pairs around
->early_demux() are confusing and not needed :
Protocol handlers are already in an RCU read lock section.
(__netif_receive_skb() does the rcu_read_lock() )
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is the IPv6 missing bits for infrastructure added in commit
41063e9dd1 (ipv4: Early TCP socket demux.)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With the routing cache removal we lost the "noref" code paths on
input, and this can kill some routing workloads.
Reinstate the noref path when we hit a cached route in the FIB
nexthops.
With help from Eric Dumazet.
Reported-by: Alexander Duyck <alexander.duyck@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
1) Remove a non needed pskb_may_pull() in tcp_v4_early_demux()
and fix a potential bug if skb->head was reallocated
(iph & th pointers were not reloaded)
TCP stack will pull/check headers anyway.
2) must reload iph in ip_rcv_finish() after early_demux()
call since skb->head might have changed.
3) skb->dev->ifindex can be now replaced by skb->skb_iif
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The "noref" argument to ip_route_input_common() is now always ignored
because we do not cache routes, and in that case we must always grab
a reference to the resulting 'dst'.
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts commit c074da2810.
This change has several unwanted side effects:
1) Sockets will cache the DST_NOCACHE route in sk->sk_rx_dst and we'll
thus never create a real cached route.
2) All TCP traffic will use DST_NOCACHE and never use the routing
cache at all.
Signed-off-by: David S. Miller <davem@davemloft.net>
DDOS synflood attacks hit badly IP route cache.
On typical machines, this cache is allowed to hold up to 8 Millions dst
entries, 256 bytes for each, for a total of 2GB of memory.
rt_garbage_collect() triggers and tries to cleanup things.
Eventually route cache is disabled but machine is under fire and might
OOM and crash.
This patch exploits the new TCP early demux, to set a nocache
boolean in case incoming TCP frame is for a not yet ESTABLISHED or
TIMEWAIT socket.
This 'nocache' boolean is then used in case dst entry is not found in
route cache, to create an unhashed dst entry (DST_NOCACHE)
SYN-cookie-ACK sent use a similar mechanism (ipv4: tcp: dont cache
output dst for syncookies), so after this patch, a machine is able to
absorb a DDOS synflood attack without polluting its IP route cache.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Hans Schillstrom <hans.schillstrom@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
And account for the fact that, when we are not forwarding, we should
bump statistic counters rather than emit an ICMP response.
RP-filter rejected lookups are still not cached.
Since -EHOSTUNREACH and -ENETUNREACH can now no longer be seen in
ip_rcv_finish(), remove those checks.
Signed-off-by: David S. Miller <davem@davemloft.net>
Yang Wei