Add a new SKB drop reason (SKB_DROP_REASON_PFMEMALLOC) to track packets
dropped due to memory pressure. In production environments, we've observed
memory exhaustion reported by memory layer stack traces, but these drops
were not properly tracked in the SKB drop reason infrastructure.
While most network code paths now properly report pfmemalloc drops, some
protocol-specific socket implementations still use sk_filter() without
drop reason tracking:
- Bluetooth L2CAP sockets
- CAIF sockets
- IUCV sockets
- Netlink sockets
- SCTP sockets
- Unix domain sockets
These remaining cases represent less common paths and could be converted
in a follow-up patch if needed. The current implementation provides
significantly improved observability into memory pressure events in the
network stack, especially for key protocols like TCP and UDP, helping to
diagnose problems in production environments.
Reported-by: Matt Fleming <mfleming@cloudflare.com>
Signed-off-by: Jesper Dangaard Brouer <hawk@kernel.org>
Link: https://patch.msgid.link/175268316579.2407873.11634752355644843509.stgit@firesoul
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Use the new helpers as a step to deal with potential dst->dev races.
v2: fix typo in ipv6_rthdr_rcv() (kernel test robot <lkp@intel.com>)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250630121934.3399505-10-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
____cacheline_aligned_in_smp attribute only makes sure to align
a field to a cache line. It does not prevent the linker to use
the remaining of the cache line for other variables, causing
potential false sharing.
Move tcp_memory_allocated into a dedicated cache line.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://patch.msgid.link/20250630093540.3052835-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Now inet_rtx_syn_ack() is only used by TCP, it can directly
call tcp_rtx_synack() instead of using an indirect call
to req->rsk_ops->rtx_syn_ack().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250626153017.2156274-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Difference between sock_i_uid() and sk_uid() is that
after sock_orphan(), sock_i_uid() returns GLOBAL_ROOT_UID
while sk_uid() returns the last cached sk->sk_uid value.
None of sock_i_uid() callers care about this.
Use sk_uid() which is much faster and inlined.
Note that diag/dump users are calling sock_i_ino() and
can not see the full benefit yet.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Reviewed-by: Maciej Żenczykowski <maze@google.com>
Link: https://patch.msgid.link/20250620133001.4090592-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
sk->sk_uid can be read while another thread changes its
value in sockfs_setattr().
Add sk_uid(const struct sock *sk) helper to factorize the needed
READ_ONCE() annotations, and add corresponding WRITE_ONCE()
where needed.
Fixes: 86741ec254 ("net: core: Add a UID field to struct sock.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Lorenzo Colitti <lorenzo@google.com>
Reviewed-by: Maciej Żenczykowski <maze@google.com>
Link: https://patch.msgid.link/20250620133001.4090592-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Load balance new TCP connections across nexthops also when they
connect to the same service at a single remote address and port.
This affects only port-based multipath hashing:
fib_multipath_hash_policy 1 or 3.
Local connections must choose both a source address and port when
connecting to a remote service, in ip_route_connect. This
"chicken-and-egg problem" (commit 2d7192d6cb ("ipv4: Sanitize and
simplify ip_route_{connect,newports}()")) is resolved by first
selecting a source address, by looking up a route using the zero
wildcard source port and address.
As a result multiple connections to the same destination address and
port have no entropy in fib_multipath_hash.
This is not a problem when forwarding, as skb-based hashing has a
4-tuple. Nor when establishing UDP connections, as autobind there
selects a port before reaching ip_route_connect.
Load balance also TCP, by using a random port in fib_multipath_hash.
Port assignment in inet_hash_connect is not atomic with
ip_route_connect. Thus ports are unpredictable, effectively random.
Implementation details:
Do not actually pass a random fl4_sport, as that affects not only
hashing, but routing more broadly, and can match a source port based
policy route, which existing wildcard port 0 will not. Instead,
define a new wildcard flowi flag that is used only for hashing.
Selecting a random source is equivalent to just selecting a random
hash entirely. But for code clarity, follow the normal 4-tuple hash
process and only update this field.
fib_multipath_hash can be reached with zero sport from other code
paths, so explicitly pass this flowi flag, rather than trying to infer
this case in the function itself.
Signed-off-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Link: https://patch.msgid.link/20250424143549.669426-3-willemdebruijn.kernel@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Devices in the networking path, such as firewalls, NATs, or routers, which
can perform SNAT or DNAT, use addresses from their own limited address
pools to masquerade the source address during forwarding, causing PAWS
verification to fail more easily.
Currently, packet loss statistics for PAWS can only be viewed through MIB,
which is a global metric and cannot be precisely obtained through tracing
to get the specific 4-tuple of the dropped packet. In the past, we had to
use kprobe ret to retrieve relevant skb information from
tcp_timewait_state_process().
We add a drop_reason pointer, similar to what previous commit does:
commit e34100c2ec ("tcp: add a drop_reason pointer to tcp_check_req()")
This commit addresses the PAWSESTABREJECTED case and also sets the
corresponding drop reason.
We use 'pwru' to test.
Before this commit:
''''
./pwru 'port 9999'
2025/04/07 13:40:19 Listening for events..
TUPLE FUNC
172.31.75.115:12345->172.31.75.114:9999(tcp) sk_skb_reason_drop(SKB_DROP_REASON_NOT_SPECIFIED)
'''
After this commit:
'''
./pwru 'port 9999'
2025/04/07 13:51:34 Listening for events..
TUPLE FUNC
172.31.75.115:12345->172.31.75.114:9999(tcp) sk_skb_reason_drop(SKB_DROP_REASON_TCP_RFC7323_TW_PAWS)
'''
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jiayuan Chen <jiayuan.chen@linux.dev>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250409112614.16153-2-jiayuan.chen@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
icsk->icsk_timeout can be replaced by icsk->icsk_retransmit_timer.expires
This saves 8 bytes in TCP/DCCP sockets and helps for better cache locality.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250324203607.703850-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
inet_connection_sock_af_ops.addr2sockaddr() hasn't been used at all
in the git era.
$ git grep addr2sockaddr $(git rev-list HEAD | tail -n 1)
Let's remove it.
Note that there was a 4 bytes hole after sockaddr_len and now it's
6 bytes, so the binary layout is not changed.
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250318060112.3729-1-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
ECN bits in TOS are always cleared when sending in ACKs in TW. Clearing
them is problematic for TCP flows that used Accurate ECN because ECN bits
decide which service queue the packet is placed into (L4S vs Classic).
Effectively, TW ACKs are always downgraded from L4S to Classic queue
which might impact, e.g., delay the ACK will experience on the path
compared with the other packets of the flow.
Change the TW ACK sending code to differentiate:
- In tcp_v4_send_reset(), commit ba9e04a7dd ("ip: fix tos reflection
in ack and reset packets") cleans ECN bits for TW reset and this is
not affected.
- In tcp_v4_timewait_ack(), ECN bits for all TW ACKs are cleaned. But now
only ECN bits of ACKs for oow data or paws_reject are cleaned, and ECN
bits of other ACKs will not be cleaned.
- In tcp_v4_reqsk_send_ack(), commit 66b13d99d9 ("ipv4: tcp: fix TOS
value in ACK messages sent from TIME_WAIT") did not clean ECN bits of
ACKs for oow data or paws_reject. But now the ECN bits rae cleaned for
these ACKs.
Signed-off-by: Ilpo Järvinen <ij@kernel.org>
Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
With AccECN, there's one additional TCP flag to be used (AE)
and ACE field that overloads the definition of AE, CWR, and
ECE flags. As tcp_flags was previously only 1 byte, the
byte-order stuff needs to be added to it's handling.
Signed-off-by: Ilpo Järvinen <ij@kernel.org>
Signed-off-by: Chia-Yu Chang <chia-yu.chang@nokia-bell-labs.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After commit 8d52da23b6 ("tcp: Defer ts_recent changes
until req is owned"), req->ts_recent is not changed anymore.
It is set once in tcp_openreq_init(), bpf_sk_assign_tcp_reqsk()
or cookie_tcp_reqsk_alloc() before the req can be seen by other
cpus/threads.
This completes the revert of eba20811f3 ("tcp: annotate
data-races around tcp_rsk(req)->ts_recent").
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Wang Hai <wanghai38@huawei.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250301201424.2046477-6-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
TCP uses of dev_net() are under RCU protection, change them
to dev_net_rcu() to get LOCKDEP support.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250301201424.2046477-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
We want to add new drop reasons for packets dropped in 3WHS in the
following patches.
tcp_rcv_state_process() has to set reason to TCP_FASTOPEN,
because tcp_check_req() will conditionally overwrite the drop_reason.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250301201424.2046477-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Current inet_sock_set_state trace from inet_csk_clone_lock() is missing
many details :
... sock:inet_sock_set_state: family=AF_INET6 protocol=IPPROTO_TCP \
sport=4901 dport=0 \
saddr=127.0.0.6 daddr=0.0.0.0 \
saddrv6=:: daddrv6=:: \
oldstate=TCP_LISTEN newstate=TCP_SYN_RECV
Only the sport gives the listener port, no other parts of the n-tuple are correct.
In this patch, I initialize relevant fields of the new socket before
calling inet_sk_set_state(newsk, TCP_SYN_RECV).
We now have a trace including all the source/destination bits.
... sock:inet_sock_set_state: family=AF_INET6 protocol=IPPROTO_TCP \
sport=4901 dport=47648 \
saddr=127.0.0.6 daddr=127.0.0.6 \
saddrv6=2002:a05:6830:1f85:: daddrv6=2001:4860:f803:65::3 \
oldstate=TCP_LISTEN newstate=TCP_SYN_RECV
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250212131328.1514243-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Under CONFIG_PROVE_RCU_LIST + CONFIG_RCU_EXPERT
hlist_for_each_entry_rcu() provides very helpful splats, which help
to find possible issues. I missed CONFIG_RCU_EXPERT=y in my testing
config the same as described in
a3e4bf7f96 ("configs/debug: make sure PROVE_RCU_LIST=y takes effect").
The fix itself is trivial: add the very same lockdep annotations
as were used to dereference ao_info from the socket.
Reported-by: Jakub Kicinski <kuba@kernel.org>
Closes: https://lore.kernel.org/netdev/20241028152645.35a8be66@kernel.org/
Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com>
Link: https://patch.msgid.link/20241030-tcp-ao-hlist-lockdep-annotate-v1-1-bf641a64d7c6@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
tcp_v6_send_response() send orphaned 'control packets'.
These are RST packets and also ACK packets sent from TIME_WAIT.
Some eBPF programs would prefer to have a meaningful skb->sk
pointer as much as possible.
This means that TCP can now attach TIME_WAIT sockets to outgoing
skbs.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Brian Vazquez <brianvv@google.com>
Link: https://patch.msgid.link/20241010174817.1543642-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
icsk->icsk_pending can be read locklessly already.
Following patch in the series will add another lockless read.
Add smp_load_acquire() and smp_store_release() annotations
because following patch will add a test in tcp_write_timer(),
and READ_ONCE()/WRITE_ONCE() alone would possibly lead to races.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20241002173042.917928-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
No lock protects tcp tw fields.
tcptw->tw_rcv_nxt can be changed from twsk_rcv_nxt_update()
while other threads might read this field.
Add READ_ONCE()/WRITE_ONCE() annotations, and make sure
tcp_timewait_state_process() reads tcptw->tw_rcv_nxt only once.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Link: https://patch.msgid.link/20240827015250.3509197-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Using a volatile qualifier for a specific struct field is unusual.
Use instead READ_ONCE()/WRITE_ONCE() where necessary.
tcp_timewait_state_process() can change tw_substate while other
threads are reading this field.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Link: https://patch.msgid.link/20240827015250.3509197-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Replace kfree_skb_reason with sk_skb_reason_drop and pass the receiving
socket to the tracepoint.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/r/202406011539.jhwBd7DX-lkp@intel.com/
Signed-off-by: Yan Zhai <yan@cloudflare.com>
Acked-by: Jesper Dangaard Brouer <hawk@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
tcp_v6_syn_recv_sock() calls ip6_dst_store() before
inet_sk(newsk)->pinet6 has been set up.
This means ip6_dst_store() writes over the parent (listener)
np->dst_cookie.
This is racy because multiple threads could share the same
parent and their final np->dst_cookie could be wrong.
Move ip6_dst_store() call after inet_sk(newsk)->pinet6
has been changed and after the copy of parent ipv6_pinfo.
Fixes: e994b2f0fb ("tcp: do not lock listener to process SYN packets")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
These fields can be read and written locklessly, add annotations
around these minor races.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cross-merge networking fixes after downstream PR.
Conflicts:
drivers/net/ethernet/ti/icssg/icssg_classifier.c
abd5576b9c ("net: ti: icssg-prueth: Add support for ICSSG switch firmware")
56a5cf538c ("net: ti: icssg-prueth: Fix start counter for ft1 filter")
https://lore.kernel.org/all/20240531123822.3bb7eadf@canb.auug.org.au/
No other adjacent changes.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
These functions have races when they:
1) Write sk->sk_err
2) call sk_error_report(sk)
3) call tcp_done(sk)
As described in prior patches in this series:
An smp_wmb() is missing.
We should call tcp_done() before sk_error_report(sk)
to have consistent tcp_poll() results on SMP hosts.
Use tcp_done_with_error() where we centralized the
correct sequence.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Link: https://lore.kernel.org/r/20240528125253.1966136-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Jason commit made checks against ACK sequence less strict
and can be exploited by attackers to establish spoofed flows
with less probes.
Innocent users might use tcp_rmem[1] == 1,000,000,000,
or something more reasonable.
An attacker can use a regular TCP connection to learn the server
initial tp->rcv_wnd, and use it to optimize the attack.
If we make sure that only the announced window (smaller than 65535)
is used for ACK validation, we force an attacker to use
65537 packets to complete the 3WHS (assuming server ISN is unknown)
Fixes: 378979e94e ("tcp: remove 64 KByte limit for initial tp->rcv_wnd value")
Link: https://datatracker.ietf.org/meeting/119/materials/slides-119-tcpm-ghost-acks-00
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Reviewed-by: Jason Xing <kerneljasonxing@gmail.com>
Link: https://lore.kernel.org/r/20240523130528.60376-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
tstamp_type is now set based on actual clockid_t compressed
into 2 bits.
To make the design scalable for future needs this commit bring in
the change to extend the tstamp_type:1 to tstamp_type:2 to support
other clockid_t timestamp.
We now support CLOCK_TAI as part of tstamp_type as part of this
commit with existing support CLOCK_MONOTONIC and CLOCK_REALTIME.
Signed-off-by: Abhishek Chauhan <quic_abchauha@quicinc.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240509211834.3235191-3-quic_abchauha@quicinc.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
mono_delivery_time was added to check if skb->tstamp has delivery
time in mono clock base (i.e. EDT) otherwise skb->tstamp has
timestamp in ingress and delivery_time at egress.
Renaming the bitfield from mono_delivery_time to tstamp_type is for
extensibilty for other timestamps such as userspace timestamp
(i.e. SO_TXTIME) set via sock opts.
As we are renaming the mono_delivery_time to tstamp_type, it makes
sense to start assigning tstamp_type based on enum defined
in this commit.
Earlier we used bool arg flag to check if the tstamp is mono in
function skb_set_delivery_time, Now the signature of the functions
accepts tstamp_type to distinguish between mono and real time.
Also skb_set_delivery_type_by_clockid is a new function which accepts
clockid to determine the tstamp_type.
In future tstamp_type:1 can be extended to support userspace timestamp
by increasing the bitfield.
Signed-off-by: Abhishek Chauhan <quic_abchauha@quicinc.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20240509211834.3235191-2-quic_abchauha@quicinc.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
There are two possible cases where TCP layer can send an RST. Since they
happen in the same place, I think using one independent reason is enough
to identify this special situation.
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Link: https://lore.kernel.org/r/20240510122502.27850-5-kerneljasonxing@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
DCCP is going away soon, and had no twsk_unique() method.
We can directly call tcp_twsk_unique() for TCP sockets.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20240507164140.940547-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Instead of (struct rt6_info *)dst casts, we can use :
#define dst_rt6_info(_ptr) \
container_of_const(_ptr, struct rt6_info, dst)
Some places needed missing const qualifiers :
ip6_confirm_neigh(), ipv6_anycast_destination(),
ipv6_unicast_destination(), has_gateway()
v2: added missing parts (David Ahern)
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
At last, we should let it work by introducing this reset reason in
trace world.
One of the possible expected outputs is:
... tcp_send_reset: skbaddr=xxx skaddr=xxx src=xxx dest=xxx
state=TCP_ESTABLISHED reason=NOT_SPECIFIED
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Reuse the dropreason logic to show the exact reason of tcp reset,
so we can finally display the corresponding item in enum sk_reset_reason
instead of reinventing new reset reasons. This patch replaces all
the prior NOT_SPECIFIED reasons.
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Adjust the parameter and support passing reason of reset which
is for now NOT_SPECIFIED. No functional changes.
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Acked-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
TCP can transform a TIMEWAIT socket into a SYN_RECV one from
a SYN packet, and the ISN of the SYNACK packet is normally
generated using TIMEWAIT tw_snd_nxt :
tcp_timewait_state_process()
...
u32 isn = tcptw->tw_snd_nxt + 65535 + 2;
if (isn == 0)
isn++;
TCP_SKB_CB(skb)->tcp_tw_isn = isn;
return TCP_TW_SYN;
This SYN packet also bypasses normal checks against listen queue
being full or not.
tcp_conn_request()
...
__u32 isn = TCP_SKB_CB(skb)->tcp_tw_isn;
...
/* TW buckets are converted to open requests without
* limitations, they conserve resources and peer is
* evidently real one.
*/
if ((syncookies == 2 || inet_csk_reqsk_queue_is_full(sk)) && !isn) {
want_cookie = tcp_syn_flood_action(sk, rsk_ops->slab_name);
if (!want_cookie)
goto drop;
}
This was using TCP_SKB_CB(skb)->tcp_tw_isn field in skb.
Unfortunately this field has been accidentally cleared
after the call to tcp_timewait_state_process() returning
TCP_TW_SYN.
Using a field in TCP_SKB_CB(skb) for a temporary state
is overkill.
Switch instead to a per-cpu variable.
As a bonus, we do not have to clear tcp_tw_isn in TCP receive
fast path.
It is temporarily set then cleared only in the TCP_TW_SYN dance.
Fixes: 4ad19de877 ("net: tcp6: fix double call of tcp_v6_fill_cb()")
Fixes: eeea10b83a ("tcp: add tcp_v4_fill_cb()/tcp_v4_restore_cb()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
tcp_v6_init_req() reads TCP_SKB_CB(skb)->tcp_tw_isn to find
out if the request socket is created by a SYN hitting a TIMEWAIT socket.
This has been buggy for a decade, lets directly pass the information
from tcp_conn_request().
This is a preparatory patch to make the following one easier to review.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Prior to this patch, what we can see by enabling trace_tcp_send is
only happening under two circumstances:
1) active rst mode
2) non-active rst mode and based on the full socket
That means the inconsistency occurs if we use tcpdump and trace
simultaneously to see how rst happens.
It's necessary that we should take into other cases into considerations,
say:
1) time-wait socket
2) no socket
...
By parsing the incoming skb and reversing its 4-tuple can
we know the exact 'flow' which might not exist.
Samples after applied this patch:
1. tcp_send_reset: skbaddr=XXX skaddr=XXX src=ip:port dest=ip:port
state=TCP_ESTABLISHED
2. tcp_send_reset: skbaddr=000...000 skaddr=XXX src=ip:port dest=ip:port
state=UNKNOWN
Note:
1) UNKNOWN means we cannot extract the right information from skb.
2) skbaddr/skaddr could be 0
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Link: https://lore.kernel.org/r/20240401073605.37335-3-kerneljasonxing@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
These structures are read in rx path, move them to net_hotdata
for better cache locality.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20240306160031.874438-13-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
It's time to let it work right now. We've already prepared for this:)
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Update three callers including both ipv4 and ipv6 and let the dropreason
mechanism work in reality.
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Like previous patch does, only moving skb drop logical code to
cookie_v6_check() for later refinement.
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts commit 0a8de364ff.
Shachar reported that Vagrant (https://www.vagrantup.com/), which is
very popular tool to manage fleet of VMs stopped to work after commit
citied in Fixes line.
The issue appears while using Vagrant to manage nested VMs.
The steps are:
* create vagrant file
* vagrant up
* vagrant halt (VM is created but shut down)
* vagrant up - fail
Vagrant up stdout:
Bringing machine 'player1' up with 'libvirt' provider...
==> player1: Creating shared folders metadata...
==> player1: Starting domain.
==> player1: Domain launching with graphics connection settings...
==> player1: -- Graphics Port: 5900
==> player1: -- Graphics IP: 127.0.0.1
==> player1: -- Graphics Password: Not defined
==> player1: -- Graphics Websocket: 5700
==> player1: Waiting for domain to get an IP address...
==> player1: Waiting for machine to boot. This may take a few minutes...
player1: SSH address: 192.168.123.61:22
player1: SSH username: vagrant
player1: SSH auth method: private key
==> player1: Attempting graceful shutdown of VM...
==> player1: Attempting graceful shutdown of VM...
==> player1: Attempting graceful shutdown of VM...
player1: Guest communication could not be established! This is usually because
player1: SSH is not running, the authentication information was changed,
player1: or some other networking issue. Vagrant will force halt, if
player1: capable.
==> player1: Attempting direct shutdown of domain...
Fixes: 0a8de364ff ("tcp: no longer abort SYN_SENT when receiving some ICMP")
Closes: https://lore.kernel.org/all/MN2PR12MB44863139E562A59329E89DBEB982A@MN2PR12MB4486.namprd12.prod.outlook.com
Signed-off-by: Shachar Kagan <skagan@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/14459261ea9f9c7d7dfb28eb004ce8734fa83ade.1704185904.git.leonro@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
np->mcast_oif is read locklessly in some contexts.
Make all accesses to this field lockless, adding appropriate
annotations.
This also makes setsockopt( IPV6_MULTICAST_IF ) lockless.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
