linux-toradex.git/include/net/netns, branch v6.15-rc7

Revert "udp_tunnel: GRO optimizations"

2025-03-25T16:15:07+00:00

Revert "udp_tunnel: use static call for GRO hooks when possible"
This reverts commit 311b36574ceaccfa3f91b74054a09cd4bb877702.

Revert "udp_tunnel: create a fastpath GRO lookup."
This reverts commit 8d4880db378350f8ed8969feea13bdc164564fc1.

There are multiple small issues with the series. In the interest
of unblocking the merge window let's opt for a revert.

Link: https://lore.kernel.org/cover.1742557254.git.pabeni@redhat.com
Signed-off-by: Jakub Kicinski

udp_tunnel: create a fastpath GRO lookup.

2025-03-18T10:40:26+00:00

Most UDP tunnels bind a socket to a local port, with ANY address, no
peer and no interface index specified.
Additionally it's quite common to have a single tunnel device per
namespace.

Track in each namespace the UDP tunnel socket respecting the above.
When only a single one is present, store a reference in the netns.

When such reference is not NULL, UDP tunnel GRO lookup just need to
match the incoming packet destination port vs the socket local port.

The tunnel socket never sets the reuse[port] flag[s]. When bound to no
address and interface, no other socket can exist in the same netns
matching the specified local port.

Matching packets with non-local destination addresses will be
aggregated, and eventually segmented as needed - no behavior changes
intended.

Note that the UDP tunnel socket reference is stored into struct
netns_ipv4 for both IPv4 and IPv6 tunnels. That is intentional to keep
all the fastpath-related netns fields in the same struct and allow
cacheline-based optimization. Currently both the IPv4 and IPv6 socket
pointer share the same cacheline as the `udp_table` field.

Reviewed-by: Willem de Bruijn 
Link: https://patch.msgid.link/4d5c319c4471161829f50cb8436841de81a5edae.1741718157.git.pabeni@redhat.com
Signed-off-by: Paolo Abeni

ipv4: fib: Namespacify fib_info hash tables.

2025-03-03T23:04:10+00:00

We will convert RTM_NEWROUTE and RTM_DELROUTE to per-netns RTNL.
Then, we need to have per-netns hash tables for struct fib_info.

Let's allocate the hash tables per netns.

fib_info_hash, fib_info_hash_bits, and fib_info_cnt are now moved
to struct netns_ipv4 and accessed with net->ipv4.fib_XXX.

Also, the netns checks are removed from fib_find_info_nh() and
fib_find_info().

Signed-off-by: Kuniyuki Iwashima 
Reviewed-by: Eric Dumazet 
Reviewed-by: David Ahern 
Link: https://patch.msgid.link/20250228042328.96624-9-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski

tcp: add tcp_rto_max_ms sysctl

2025-02-11T12:08:00+00:00

Previous patch added a TCP_RTO_MAX_MS socket option
to tune a TCP socket max RTO value.

Many setups prefer to change a per netns sysctl.

This patch adds /proc/sys/net/ipv4/tcp_rto_max_ms

Its initial value is 120000 (120 seconds).

Keep in mind that a decrease of tcp_rto_max_ms
means shorter overall timeouts, unless tcp_retries2
sysctl is increased.

Signed-off-by: Eric Dumazet 
Reviewed-by: Jason Xing 
Reviewed-by: Neal Cardwell 
Reviewed-by: Kuniyuki Iwashima 
Signed-off-by: Paolo Abeni

tcp: Add sysctl to configure TIME-WAIT reuse delay

2024-12-12T04:17:33+00:00

Today we have a hardcoded delay of 1 sec before a TIME-WAIT socket can be
reused by reopening a connection. This is a safe choice based on an
assumption that the other TCP timestamp clock frequency, which is unknown
to us, may be as low as 1 Hz (RFC 7323, section 5.4).

However, this means that in the presence of short lived connections with an
RTT of couple of milliseconds, the time during which a 4-tuple is blocked
from reuse can be orders of magnitude longer that the connection lifetime.
Combined with a reduced pool of ephemeral ports, when using
IP_LOCAL_PORT_RANGE to share an egress IP address between hosts [1], the
long TIME-WAIT reuse delay can lead to port exhaustion, where all available
4-tuples are tied up in TIME-WAIT state.

Turn the reuse delay into a per-netns setting so that sysadmins can make
more aggressive assumptions about remote TCP timestamp clock frequency and
shorten the delay in order to allow connections to reincarnate faster.

Note that applications can completely bypass the TIME-WAIT delay protection
already today by locking the local port with bind() before connecting. Such
immediate connection reuse may result in PAWS failing to detect old
duplicate segments, leaving us with just the sequence number check as a
safety net.

This new configurable offers a trade off where the sysadmin can balance
between the risk of PAWS detection failing to act versus exhausting ports
by having sockets tied up in TIME-WAIT state for too long.

[1] https://lpc.events/event/16/contributions/1349/

Signed-off-by: Jakub Sitnicki 
Reviewed-by: Eric Dumazet 
Reviewed-by: Jason Xing 
Link: https://patch.msgid.link/20241209-jakub-krn-909-poc-msec-tw-tstamp-v2-2-66aca0eed03e@cloudflare.com
Signed-off-by: Jakub Kicinski

xfrm: Add an inbound percpu state cache.

2024-10-29T10:56:18+00:00

Now that we can have percpu xfrm states, the number of active
states might increase. To get a better lookup performance,
we add a percpu cache to cache the used inbound xfrm states.

Signed-off-by: Steffen Klassert 
Tested-by: Antony Antony 
Tested-by: Tobias Brunner

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2024-10-25T07:08:22+00:00

Cross-merge networking fixes after downstream PR.

No conflicts and no adjacent changes.

Signed-off-by: Paolo Abeni

ipv4: use READ_ONCE()/WRITE_ONCE() on net->ipv4.fib_seq

2024-10-11T22:35:05+00:00

Using RTNL to protect ops->fib_rules_seq reads seems a big hammer.

Writes are protected by RTNL.
We can use READ_ONCE() when reading it.

Constify 'struct net' argument of fib4_rules_seq_read()

Signed-off-by: Eric Dumazet 
Reviewed-by: Kuniyuki Iwashima 
Reviewed-by: David Ahern 
Link: https://patch.msgid.link/20241009184405.3752829-3-edumazet@google.com
Signed-off-by: Jakub Kicinski

tcp: move sysctl_tcp_l3mdev_accept to netns_ipv4_read_rx

2024-10-11T15:45:24+00:00

sysctl_tcp_l3mdev_accept is read from TCP receive fast path from
tcp_v6_early_demux(),
 __inet6_lookup_established,
  inet_request_bound_dev_if().

Move it to netns_ipv4_read_rx.

Remove the '#ifdef CONFIG_NET_L3_MASTER_DEV' that was guarding
its definition.

Note this adds a hole of three bytes that could be filled later.

Signed-off-by: Eric Dumazet 
Reviewed-by: David Ahern 
Cc: Wei Wang 
Cc: Coco Li 
Link: https://patch.msgid.link/20241010034100.320832-1-edumazet@google.com
Signed-off-by: Jakub Kicinski

ipv4: Namespacify IPv4 address GC.

2024-10-10T03:08:08+00:00

Each IPv4 address could have a lifetime, which is useful for DHCP,
and GC is periodically executed as check_lifetime_work.

check_lifetime() does the actual GC under RTNL.

  1. Acquire RTNL
  2. Iterate inet_addr_lst
  3. Remove IPv4 address if expired
  4. Release RTNL

Namespacifying the GC is required for per-netns RTNL, but using the
per-netns hash table will shorten the time on the hash bucket iteration
under RTNL.

Let's add per-netns GC work and use the per-netns hash table.

Reviewed-by: Eric Dumazet 
Signed-off-by: Kuniyuki Iwashima 
Link: https://patch.msgid.link/20241008172906.1326-4-kuniyu@amazon.com
Signed-off-by: Jakub Kicinski