Revert "udp_tunnel: GRO optimizations"

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

Revert "udp_tunnel: create a fa

Revert "udp_tunnel: GRO optimizations"

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/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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udp_tunnel: create a fastpath GRO lookup.

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

udp_tunnel: create a fastpath GRO lookup.

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 <[email protected]>
Link: https://patch.msgid.link/4d5c319c4471161829f50cb8436841de81a5edae.1741718157.git.pabeni@redhat.com
Signed-off-by: Paolo Abeni <[email protected]>

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ipv6/udp: Add 4-tuple hash for connected socket

Implement ipv6 udp hash4 like that in ipv4. The major difference is that
the hash value should be calculated with udp6_ehashfn(). Besides,
ipv4-mapped

ipv6/udp: Add 4-tuple hash for connected socket

Implement ipv6 udp hash4 like that in ipv4. The major difference is that
the hash value should be calculated with udp6_ehashfn(). Besides,
ipv4-mapped ipv6 address is handled before hash() and rehash(). Export
udp_ehashfn because now we use it in udpv6 rehash.

Core procedures of hash/unhash/rehash are same as ipv4, and udpv4 and
udpv6 share the same udptable, so some functions in ipv4 hash4 can also
be shared.

Co-developed-by: Cambda Zhu <[email protected]>
Signed-off-by: Cambda Zhu <[email protected]>
Co-developed-by: Fred Chen <[email protected]>
Signed-off-by: Fred Chen <[email protected]>
Co-developed-by: Yubing Qiu <[email protected]>
Signed-off-by: Yubing Qiu <[email protected]>
Signed-off-by: Philo Lu <[email protected]>
Acked-by: Willem de Bruijn <[email protected]>
Acked-by: Paolo Abeni <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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ipv4/udp: Add 4-tuple hash for connected socket

Currently, the udp_table has two hash table, the port hash and portaddr
hash. Usually for UDP servers, all sockets have the same local port and
addr,

ipv4/udp: Add 4-tuple hash for connected socket

Currently, the udp_table has two hash table, the port hash and portaddr
hash. Usually for UDP servers, all sockets have the same local port and
addr, so they are all on the same hash slot within a reuseport group.

In some applications, UDP servers use connect() to manage clients. In
particular, when firstly receiving from an unseen 4 tuple, a new socket
is created and connect()ed to the remote addr:port, and then the fd is
used exclusively by the client.

Once there are connected sks in a reuseport group, udp has to score all
sks in the same hash2 slot to find the best match. This could be
inefficient with a large number of connections, resulting in high
softirq overhead.

To solve the problem, this patch implement 4-tuple hash for connected
udp sockets. During connect(), hash4 slot is updated, as well as a
corresponding counter, hash4_cnt, in hslot2. In __udp4_lib_lookup(),
hslot4 will be searched firstly if the counter is non-zero. Otherwise,
hslot2 is used like before. Note that only connected sockets enter this
hash4 path, while un-connected ones are not affected.

hlist_nulls is used for hash4, because we probably move to another hslot
wrongly when lookup with concurrent rehash. Then we check nulls at the
list end to see if we should restart lookup. Because udp does not use
SLAB_TYPESAFE_BY_RCU, we don't need to touch sk_refcnt when lookup.

Stress test results (with 1 cpu fully used) are shown below, in pps:
(1) _un-connected_ socket as server
[a] w/o hash4: 1,825176
[b] w/ hash4: 1,831750 (+0.36%)

(2) 500 _connected_ sockets as server
[c] w/o hash4: 290860 (only 16% of [a])
[d] w/ hash4: 1,889658 (+3.1% compared with [b])

With hash4, compute_score is skipped when lookup, so [d] is slightly
better than [b].

Co-developed-by: Cambda Zhu <[email protected]>
Signed-off-by: Cambda Zhu <[email protected]>
Co-developed-by: Fred Chen <[email protected]>
Signed-off-by: Fred Chen <[email protected]>
Co-developed-by: Yubing Qiu <[email protected]>
Signed-off-by: Yubing Qiu <[email protected]>
Signed-off-by: Philo Lu <[email protected]>
Acked-by: Willem de Bruijn <[email protected]>
Acked-by: Paolo Abeni <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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net/udp: Add 4-tuple hash list basis

Add a new hash list, hash4, in udp table. It will be used to implement
4-tuple hash for connected udp sockets. This patch adds the hlist to
table, and implements

net/udp: Add 4-tuple hash list basis

Add a new hash list, hash4, in udp table. It will be used to implement
4-tuple hash for connected udp sockets. This patch adds the hlist to
table, and implements helpers and the initialization. 4-tuple hash is
implemented in the following patch.

hash4 uses hlist_nulls to avoid moving wrongly onto another hlist due to
concurrent rehash, because rehash() can happen with lookup().

Co-developed-by: Cambda Zhu <[email protected]>
Signed-off-by: Cambda Zhu <[email protected]>
Co-developed-by: Fred Chen <[email protected]>
Signed-off-by: Fred Chen <[email protected]>
Co-developed-by: Yubing Qiu <[email protected]>
Signed-off-by: Yubing Qiu <[email protected]>
Signed-off-by: Philo Lu <[email protected]>
Acked-by: Willem de Bruijn <[email protected]>
Acked-by: Paolo Abeni <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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net/udp: Add a new struct for hash2 slot

Preparing for udp 4-tuple hash (uhash4 for short).

To implement uhash4 without cache line missing when lookup, hslot2 is
used to record the number of hashed

net/udp: Add a new struct for hash2 slot

Preparing for udp 4-tuple hash (uhash4 for short).

To implement uhash4 without cache line missing when lookup, hslot2 is
used to record the number of hashed sockets in hslot4. Thus adding a new
struct udp_hslot_main with field hash4_cnt, which is used by hash2. The
new struct is used to avoid doubling the size of udp_hslot.

Before uhash4 lookup, firstly checking hash4_cnt to see if there are
hashed sks in hslot4. Because hslot2 is always used in lookup, there is
no cache line miss.

Related helpers are updated, and use the helpers as possible.

uhash4 is implemented in following patches.

Signed-off-by: Philo Lu <[email protected]>
Acked-by: Willem de Bruijn <[email protected]>
Acked-by: Paolo Abeni <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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net: Correct spelling in headers

Correct spelling in Networking headers.
As reported by codespell.

Signed-off-by: Simon Horman <[email protected]>
Link: https://patch.msgid.link/20240822-net-spell-v

net: Correct spelling in headers

Correct spelling in Networking headers.
As reported by codespell.

Signed-off-by: Simon Horman <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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ipv6: udp: constify 'struct net' parameter of socket lookups

Following helpers do not touch their 'struct net' argument.

- udp6_lib_lookup()
- __udp6_lib_lookup()

Signed-off-by: Eric Dumazet <edum

ipv6: udp: constify 'struct net' parameter of socket lookups

Following helpers do not touch their 'struct net' argument.

- udp6_lib_lookup()
- __udp6_lib_lookup()

Signed-off-by: Eric Dumazet <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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udp: constify 'struct net' parameter of socket lookups

Following helpers do not touch their 'struct net' argument.

- udp_sk_bound_dev_eq()
- udp4_lib_lookup()
- __udp4_lib_lookup()

Signed-off-by:

udp: constify 'struct net' parameter of socket lookups

Following helpers do not touch their 'struct net' argument.

- udp_sk_bound_dev_eq()
- udp4_lib_lookup()
- __udp4_lib_lookup()

Signed-off-by: Eric Dumazet <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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new helper: copy_to_iter_full()

... and convert copy_linear_skb() to using that.

Signed-off-by: Al Viro <[email protected]>

udp/udplite: Remove unused function declarations udp{,lite}_get_port()

Commit 6ba5a3c52da0 ("[UDP]: Make full use of proto.h.udp_hash innovation.")
removed these implementations but leave declaratio

udp/udplite: Remove unused function declarations udp{,lite}_get_port()

Commit 6ba5a3c52da0 ("[UDP]: Make full use of proto.h.udp_hash innovation.")
removed these implementations but leave declarations.

Signed-off-by: Yue Haibing <[email protected]>
Reviewed-by: Willem de Bruijn <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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udp: Remove unused function declaration udp_bpf_get_proto()

commit 8a59f9d1e3d4 ("sock: Introduce sk->sk_prot->psock_update_sk_prot()")
left behind this.

Signed-off-by: Yue Haibing <yuehaibing@huaw

udp: Remove unused function declaration udp_bpf_get_proto()

commit 8a59f9d1e3d4 ("sock: Introduce sk->sk_prot->psock_update_sk_prot()")
left behind this.

Signed-off-by: Yue Haibing <[email protected]>
Reviewed-by: Willem de Bruijn <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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net: ioctl: Use kernel memory on protocol ioctl callbacks

Most of the ioctls to net protocols operates directly on userspace
argument (arg). Usually doing get_user()/put_user() directly in the
ioctl

net: ioctl: Use kernel memory on protocol ioctl callbacks

Most of the ioctls to net protocols operates directly on userspace
argument (arg). Usually doing get_user()/put_user() directly in the
ioctl callback. This is not flexible, because it is hard to reuse these
functions without passing userspace buffers.

Change the "struct proto" ioctls to avoid touching userspace memory and
operate on kernel buffers, i.e., all protocol's ioctl callbacks is
adapted to operate on a kernel memory other than on userspace (so, no
more {put,get}_user() and friends being called in the ioctl callback).

This changes the "struct proto" ioctl format in the following way:

int (*ioctl)(struct sock *sk, int cmd,
- unsigned long arg);
+ int *karg);

(Important to say that this patch does not touch the "struct proto_ops"
protocols)

So, the "karg" argument, which is passed to the ioctl callback, is a
pointer allocated to kernel space memory (inside a function wrapper).
This buffer (karg) may contain input argument (copied from userspace in
a prep function) and it might return a value/buffer, which is copied
back to userspace if necessary. There is not one-size-fits-all format
(that is I am using 'may' above), but basically, there are three type of
ioctls:

1) Do not read from userspace, returns a result to userspace
2) Read an input parameter from userspace, and does not return anything
to userspace
3) Read an input from userspace, and return a buffer to userspace.

The default case (1) (where no input parameter is given, and an "int" is
returned to userspace) encompasses more than 90% of the cases, but there
are two other exceptions. Here is a list of exceptions:

* Protocol RAW:
* cmd = SIOCGETVIFCNT:
* input and output = struct sioc_vif_req
* cmd = SIOCGETSGCNT
* input and output = struct sioc_sg_req
* Explanation: for the SIOCGETVIFCNT case, userspace passes the input
argument, which is struct sioc_vif_req. Then the callback populates
the struct, which is copied back to userspace.

* Protocol RAW6:
* cmd = SIOCGETMIFCNT_IN6
* input and output = struct sioc_mif_req6
* cmd = SIOCGETSGCNT_IN6
* input and output = struct sioc_sg_req6

* Protocol PHONET:
* cmd == SIOCPNADDRESOURCE | SIOCPNDELRESOURCE
* input int (4 bytes)
* Nothing is copied back to userspace.

For the exception cases, functions sock_sk_ioctl_inout() will
copy the userspace input, and copy it back to kernel space.

The wrapper that prepare the buffer and put the buffer back to user is
sk_ioctl(), so, instead of calling sk->sk_prot->ioctl(), the callee now
calls sk_ioctl(), which will handle all cases.

Signed-off-by: Breno Leitao <[email protected]>
Reviewed-by: Willem de Bruijn <[email protected]>
Reviewed-by: David Ahern <[email protected]>
Reviewed-by: Kuniyuki Iwashima <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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net: move gso declarations and functions to their own files

Move declarations into include/net/gso.h and code into net/core/gso.c

Signed-off-by: Eric Dumazet <[email protected]>
Cc: Stanislav Fom

net: move gso declarations and functions to their own files

Move declarations into include/net/gso.h and code into net/core/gso.c

Signed-off-by: Eric Dumazet <[email protected]>
Cc: Stanislav Fomichev <[email protected]>
Reviewed-by: Simon Horman <[email protected]>
Reviewed-by: David Ahern <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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ipv4, ipv6: Use splice_eof() to flush

Allow splice to undo the effects of MSG_MORE after prematurely ending a
splice/sendfile due to getting an EOF condition (->splice_read() returned
0) after splic

ipv4, ipv6: Use splice_eof() to flush

Allow splice to undo the effects of MSG_MORE after prematurely ending a
splice/sendfile due to getting an EOF condition (->splice_read() returned
0) after splice had called sendmsg() with MSG_MORE set when the user didn't
set MSG_MORE.

For UDP, a pending packet will not be emitted if the socket is closed
before it is flushed; with this change, it be flushed by ->splice_eof().

For TCP, it's not clear that MSG_MORE is actually effective.

Suggested-by: Linus Torvalds <[email protected]>
Link: https://lore.kernel.org/r/CAHk-=wh=V579PDYvkpnTobCLGczbgxpMgGmmhqiTyE34Cpi5Gg@mail.gmail.com/
Signed-off-by: David Howells <[email protected]>
cc: Kuniyuki Iwashima <[email protected]>
cc: Willem de Bruijn <[email protected]>
cc: David Ahern <[email protected]>
cc: Jens Axboe <[email protected]>
cc: Matthew Wilcox <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

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udp: seq_file: Remove bpf_seq_afinfo from udp_iter_state

This is a preparatory commit to remove the field. The field was
previously shared between proc fs and BPF UDP socket iterators. As the
follow

udp: seq_file: Remove bpf_seq_afinfo from udp_iter_state

This is a preparatory commit to remove the field. The field was
previously shared between proc fs and BPF UDP socket iterators. As the
follow-up commits will decouple the implementation for the iterators,
remove the field. As for BPF socket iterator, filtering of sockets is
exepected to be done in BPF programs.

Suggested-by: Martin KaFai Lau <[email protected]>
Signed-off-by: Aditi Ghag <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Martin KaFai Lau <[email protected]>

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udp: track the forward memory release threshold in an hot cacheline

When the receiver process and the BH runs on different cores,
udp_rmem_release() experience a cache miss while accessing sk_rcvbuf

udp: track the forward memory release threshold in an hot cacheline

When the receiver process and the BH runs on different cores,
udp_rmem_release() experience a cache miss while accessing sk_rcvbuf,
as the latter shares the same cacheline with sk_forward_alloc, written
by the BH.

With this patch, UDP tracks the rcvbuf value and its update via custom
SOL_SOCKET socket options, and copies the forward memory threshold value
used by udp_rmem_release() in a different cacheline, already accessed by
the above function and uncontended.

Since the UDP socket init operation grown a bit, factor out the common
code between v4 and v6 in a shared helper.

Overall the above give a 10% peek throughput increase under UDP flood.

Signed-off-by: Paolo Abeni <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Acked-by: Kuniyuki Iwashima <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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tcp/udp: Call inet6_destroy_sock() in IPv6 sk->sk_destruct().

Originally, inet6_sk(sk)->XXX were changed under lock_sock(), so we were
able to clean them up by calling inet6_destroy_sock() during th

tcp/udp: Call inet6_destroy_sock() in IPv6 sk->sk_destruct().

Originally, inet6_sk(sk)->XXX were changed under lock_sock(), so we were
able to clean them up by calling inet6_destroy_sock() during the IPv6 ->
IPv4 conversion by IPV6_ADDRFORM. However, commit 03485f2adcde ("udpv6:
Add lockless sendmsg() support") added a lockless memory allocation path,
which could cause a memory leak:

setsockopt(IPV6_ADDRFORM) sendmsg()
+-----------------------+ +-------+
- do_ipv6_setsockopt(sk, ...) - udpv6_sendmsg(sk, ...)
- sockopt_lock_sock(sk) ^._ called via udpv6_prot
- lock_sock(sk) before WRITE_ONCE()
- WRITE_ONCE(sk->sk_prot, &tcp_prot)
- inet6_destroy_sock() - if (!corkreq)
- sockopt_release_sock(sk) - ip6_make_skb(sk, ...)
- release_sock(sk) ^._ lockless fast path for
the non-corking case

- __ip6_append_data(sk, ...)
- ipv6_local_rxpmtu(sk, ...)
- xchg(&np->rxpmtu, skb)
^._ rxpmtu is never freed.

- goto out_no_dst;

- lock_sock(sk)

For now, rxpmtu is only the case, but not to miss the future change
and a similar bug fixed in commit e27326009a3d ("net: ping6: Fix
memleak in ipv6_renew_options()."), let's set a new function to IPv6
sk->sk_destruct() and call inet6_cleanup_sock() there. Since the
conversion does not change sk->sk_destruct(), we can guarantee that
we can clean up IPv6 resources finally.

We can now remove all inet6_destroy_sock() calls from IPv6 protocol
specific ->destroy() functions, but such changes are invasive to
backport. So they can be posted as a follow-up later for net-next.

Fixes: 03485f2adcde ("udpv6: Add lockless sendmsg() support")
Signed-off-by: Kuniyuki Iwashima <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

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udp: Fix a data-race around sysctl_udp_l3mdev_accept.

While reading sysctl_udp_l3mdev_accept, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.

Fixes: 63a6fff353d0 ("n

udp: Fix a data-race around sysctl_udp_l3mdev_accept.

While reading sysctl_udp_l3mdev_accept, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.

Fixes: 63a6fff353d0 ("net: Avoid receiving packets with an l3mdev on unbound UDP sockets")
Signed-off-by: Kuniyuki Iwashima <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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tcp/udp: Make early_demux back namespacified.

Commit e21145a9871a ("ipv4: namespacify ip_early_demux sysctl knob") made
it possible to enable/disable early_demux on a per-netns basis. Then, we
intr

tcp/udp: Make early_demux back namespacified.

Commit e21145a9871a ("ipv4: namespacify ip_early_demux sysctl knob") made
it possible to enable/disable early_demux on a per-netns basis. Then, we
introduced two knobs, tcp_early_demux and udp_early_demux, to switch it for
TCP/UDP in commit dddb64bcb346 ("net: Add sysctl to toggle early demux for
tcp and udp"). However, the .proc_handler() was wrong and actually
disabled us from changing the behaviour in each netns.

We can execute early_demux if net.ipv4.ip_early_demux is on and each proto
.early_demux() handler is not NULL. When we toggle (tcp|udp)_early_demux,
the change itself is saved in each netns variable, but the .early_demux()
handler is a global variable, so the handler is switched based on the
init_net's sysctl variable. Thus, netns (tcp|udp)_early_demux knobs have
nothing to do with the logic. Whether we CAN execute proto .early_demux()
is always decided by init_net's sysctl knob, and whether we DO it or not is
by each netns ip_early_demux knob.

This patch namespacifies (tcp|udp)_early_demux again. For now, the users
of the .early_demux() handler are TCP and UDP only, and they are called
directly to avoid retpoline. So, we can remove the .early_demux() handler
from inet6?_protos and need not dereference them in ip6?_rcv_finish_core().
If another proto needs .early_demux(), we can restore it at that time.

Fixes: dddb64bcb346 ("net: Add sysctl to toggle early demux for tcp and udp")
Signed-off-by: Kuniyuki Iwashima <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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net: Introduce a new proto_ops ->read_skb()

Currently both splice() and sockmap use ->read_sock() to
read skb from receive queue, but for sockmap we only read
one entire skb at a time, so ->read_soc

net: Introduce a new proto_ops ->read_skb()

Currently both splice() and sockmap use ->read_sock() to
read skb from receive queue, but for sockmap we only read
one entire skb at a time, so ->read_sock() is too conservative
to use. Introduce a new proto_ops ->read_skb() which supports
this sematic, with this we can finally pass the ownership of
skb to recv actors.

For non-TCP protocols, all ->read_sock() can be simply
converted to ->read_skb().

Signed-off-by: Cong Wang <[email protected]>
Signed-off-by: Daniel Borkmann <[email protected]>
Reviewed-by: John Fastabend <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]

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net: add per_cpu_fw_alloc field to struct proto

Each protocol having a ->memory_allocated pointer gets a corresponding
per-cpu reserve, that following patches will use.

Instead of having reserved b

net: add per_cpu_fw_alloc field to struct proto

Each protocol having a ->memory_allocated pointer gets a corresponding
per-cpu reserve, that following patches will use.

Instead of having reserved bytes per socket,
we want to have per-cpu reserves.

Signed-off-by: Eric Dumazet <[email protected]>
Reviewed-by: Shakeel Butt <[email protected]>
Acked-by: Soheil Hassas Yeganeh <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

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net: remove noblock parameter from recvmsg() entities

The internal recvmsg() functions have two parameters 'flags' and 'noblock'
that were merged inside skb_recv_datagram(). As a follow up patch to

net: remove noblock parameter from recvmsg() entities

The internal recvmsg() functions have two parameters 'flags' and 'noblock'
that were merged inside skb_recv_datagram(). As a follow up patch to commit
f4b41f062c42 ("net: remove noblock parameter from skb_recv_datagram()")
this patch removes the separate 'noblock' parameter for recvmsg().

Analogue to the referenced patch for skb_recv_datagram() the 'flags' and
'noblock' parameters are unnecessarily split up with e.g.

err = sk->sk_prot->recvmsg(sk, msg, size, flags & MSG_DONTWAIT,
flags & ~MSG_DONTWAIT, &addr_len);

or in

err = INDIRECT_CALL_2(sk->sk_prot->recvmsg, tcp_recvmsg, udp_recvmsg,
sk, msg, size, flags & MSG_DONTWAIT,
flags & ~MSG_DONTWAIT, &addr_len);

instead of simply using only flags all the time and check for MSG_DONTWAIT
where needed (to preserve for the formerly separated no(n)block condition).

Signed-off-by: Oliver Hartkopp <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Paolo Abeni <[email protected]>

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net: move gro definitions to include/net/gro.h

include/linux/netdevice.h became too big, move gro stuff
into include/net/gro.h

Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: David

net: move gro definitions to include/net/gro.h

include/linux/netdevice.h became too big, move gro stuff
into include/net/gro.h

Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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net: multicast: calculate csum of looped-back and forwarded packets

During a testing of an user-space application which transmits UDP
multicast datagrams and utilizes multicast routing to send the U

net: multicast: calculate csum of looped-back and forwarded packets

During a testing of an user-space application which transmits UDP
multicast datagrams and utilizes multicast routing to send the UDP
datagrams out of defined network interfaces, I've found a multicast
router does not fill-in UDP checksum into locally produced, looped-back
and forwarded UDP datagrams, if an original output NIC the datagrams
are sent to has UDP TX checksum offload enabled.

The datagrams are sent malformed out of the NIC the datagrams have been
forwarded to.

It is because:

1. If TX checksum offload is enabled on the output NIC, UDP checksum
is not calculated by kernel and is not filled into skb data.

2. dev_loopback_xmit(), which is called solely by
ip_mc_finish_output(), sets skb->ip_summed = CHECKSUM_UNNECESSARY
unconditionally.

3. Since 35fc92a9 ("[NET]: Allow forwarding of ip_summed except
CHECKSUM_COMPLETE"), the ip_summed value is preserved during
forwarding.

4. If ip_summed != CHECKSUM_PARTIAL, checksum is not calculated during
a packet egress.

The minimum fix in dev_loopback_xmit():

1. Preserves skb->ip_summed CHECKSUM_PARTIAL. This is the
case when the original output NIC has TX checksum offload enabled.
The effects are:

a) If the forwarding destination interface supports TX checksum
offloading, the NIC driver is responsible to fill-in the
checksum.

b) If the forwarding destination interface does NOT support TX
checksum offloading, checksums are filled-in by kernel before
skb is submitted to the NIC driver.

c) For local delivery, checksum validation is skipped as in the
case of CHECKSUM_UNNECESSARY, thanks to skb_csum_unnecessary().

2. Translates ip_summed CHECKSUM_NONE to CHECKSUM_UNNECESSARY. It
means, for CHECKSUM_NONE, the behavior is unmodified and is there
to skip a looped-back packet local delivery checksum validation.

Signed-off-by: Cyril Strejc <[email protected]>
Reviewed-by: Willem de Bruijn <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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