user/sven/linux.git/include/linux/udp.h, branch v6.2.7

udp: Introduce optional per-netns hash table.

2022-11-16T09:43:35Z

The maximum hash table size is 64K due to the nature of the protocol. [0] It's smaller than TCP, and fewer sockets can cause a performance drop. On an EC2 c5.24xlarge instance (192 GiB memory), after running iperf3 in different netns, creating 32Mi sockets without data transfer in the root netns causes regression for the iperf3's connection. uhash_entries sockets length Gbps 64K 1 1 5.69 1Mi 16 5.27 2Mi 32 4.90 4Mi 64 4.09 8Mi 128 2.96 16Mi 256 2.06 32Mi 512 1.12 The per-netns hash table breaks the lengthy lists into shorter ones. It is useful on a multi-tenant system with thousands of netns. With smaller hash tables, we can look up sockets faster, isolate noisy neighbours, and reduce lock contention. The max size of the per-netns table is 64K as well. This is because the possible hash range by udp_hashfn() always fits in 64K within the same netns and we cannot make full use of the whole buckets larger than 64K. /* 0 < num < 64K -> X < hash < X + 64K */ (num + net_hash_mix(net)) & mask; Also, the min size is 128. We use a bitmap to search for an available port in udp_lib_get_port(). To keep the bitmap on the stack and not fire the CONFIG_FRAME_WARN error at build time, we round up the table size to 128. The sysctl usage is the same with TCP: $ dmesg | cut -d ' ' -f 6- | grep "UDP hash" UDP hash table entries: 65536 (order: 9, 2097152 bytes, vmalloc) # sysctl net.ipv4.udp_hash_entries net.ipv4.udp_hash_entries = 65536 # can be changed by uhash_entries # sysctl net.ipv4.udp_child_hash_entries net.ipv4.udp_child_hash_entries = 0 # disabled by default # ip netns add test1 # ip netns exec test1 sysctl net.ipv4.udp_hash_entries net.ipv4.udp_hash_entries = -65536 # share the global table # sysctl -w net.ipv4.udp_child_hash_entries=100 net.ipv4.udp_child_hash_entries = 100 # ip netns add test2 # ip netns exec test2 sysctl net.ipv4.udp_hash_entries net.ipv4.udp_hash_entries = 128 # own a per-netns table with 2^n buckets We could optimise the hash table lookup/iteration further by removing the netns comparison for the per-netns one in the future. Also, we could optimise the sparse udp_hslot layout by putting it in udp_table. [0]: https://lore.kernel.org/netdev/4ACC2815.7010101@gmail.com/ Signed-off-by: Kuniyuki Iwashima Signed-off-by: David S. Miller

net: Change the udp encap_err_rcv to allow use of {ip,ipv6}_icmp_error()

2022-11-08T16:42:28Z

Change the udp encap_err_rcv signature to match ip_icmp_error() and ipv6_icmp_error() so that those can be used from the called function and export them. Signed-off-by: David Howells cc: Marc Dionne cc: linux-afs@lists.infradead.org cc: netdev@vger.kernel.org

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

2022-10-24T09:52:50Z

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 Reviewed-by: Eric Dumazet Acked-by: Kuniyuki Iwashima Signed-off-by: David S. Miller

rxrpc: Fix ICMP/ICMP6 error handling

2022-09-01T10:42:12Z

Because rxrpc pretends to be a tunnel on top of a UDP/UDP6 socket, allowing it to siphon off UDP packets early in the handling of received UDP packets thereby avoiding the packet going through the UDP receive queue, it doesn't get ICMP packets through the UDP ->sk_error_report() callback. In fact, it doesn't appear that there's any usable option for getting hold of ICMP packets. Fix this by adding a new UDP encap hook to distribute error messages for UDP tunnels. If the hook is set, then the tunnel driver will be able to see ICMP packets. The hook provides the offset into the packet of the UDP header of the original packet that caused the notification. An alternative would be to call the ->error_handler() hook - but that requires that the skbuff be cloned (as ip_icmp_error() or ipv6_cmp_error() do, though isn't really necessary or desirable in rxrpc's case is we want to parse them there and then, not queue them). Changes ======= ver #3) - Fixed an uninitialised variable. ver #2) - Fixed some missing CONFIG_AF_RXRPC_IPV6 conditionals. Fixes: 5271953cad31 ("rxrpc: Use the UDP encap_rcv hook") Signed-off-by: David Howells

udp: remove inner_udp_hdr()

2022-01-27T13:53:27Z

Not used since added in v3.8. Signed-off-by: Jakub Kicinski Acked-by: Willem de Bruijn Signed-off-by: David S. Miller

vxlan: allow L4 GRO passthrough

2021-03-31T00:06:49Z

When passing up an UDP GSO packet with L4 aggregation, there is no need to segment it at the vxlan level. We can propagate the packet untouched and let it be segmented later, if needed. Introduce an helper to allow let the UDP socket to accept any L4 aggregation and use it in the vxlan driver. v1 -> v2: - updated to use the newly introduced UDP socket 'accept*' fields Signed-off-by: Paolo Abeni Reviewed-by: Willem de Bruijn Signed-off-by: David S. Miller

udp: never accept GSO_FRAGLIST packets

2021-03-31T00:06:49Z

Currently the UDP protocol delivers GSO_FRAGLIST packets to the sockets without the expected segmentation. This change addresses the issue introducing and maintaining a couple of new fields to explicitly accept SKB_GSO_UDP_L4 or GSO_FRAGLIST packets. Additionally updates udp_unexpected_gso() accordingly. UDP sockets enabling UDP_GRO stil keep accept_udp_fraglist zeroed. v1 -> v2: - use 2 bits instead of a whole GSO bitmask (Willem) Fixes: 9fd1ff5d2ac7 ("udp: Support UDP fraglist GRO/GSO.") Signed-off-by: Paolo Abeni Reviewed-by: Willem de Bruijn Signed-off-by: David S. Miller

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

2019-05-30T18:26:32Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman

udp: Handle ICMP errors for tunnels with same destination port on both endpoints

2018-11-09T01:13:08Z

For both IPv4 and IPv6, if we can't match errors to a socket, try tunnels before ignoring them. Look up a socket with the original source and destination ports as found in the UDP packet inside the ICMP payload, this will work for tunnels that force the same destination port for both endpoints, i.e. VXLAN and GENEVE. Actually, lwtunnels could break this assumption if they are configured by an external control plane to have different destination ports on the endpoints: in this case, we won't be able to trace ICMP messages back to them. For IPv6 redirect messages, call ip6_redirect() directly with the output interface argument set to the interface we received the packet from (as it's the very interface we should build the exception on), otherwise the new nexthop will be rejected. There's no such need for IPv4. Tunnels can now export an encap_err_lookup() operation that indicates a match. Pass the packet to the lookup function, and if the tunnel driver reports a matching association, continue with regular ICMP error handling. v2: - Added newline between network and transport header sets in __udp{4,6}_lib_err_encap() (David Miller) - Removed redundant skb_reset_network_header(skb); in __udp4_lib_err_encap() - Removed redundant reassignment of iph in __udp4_lib_err_encap() (Sabrina Dubroca) - Edited comment to __udp{4,6}_lib_err_encap() to reflect the fact this won't work with lwtunnels configured to use asymmetric ports. By the way, it's VXLAN, not VxLAN (Jiri Benc) Signed-off-by: Stefano Brivio Reviewed-by: Sabrina Dubroca Signed-off-by: David S. Miller

udp: cope with UDP GRO packet misdirection

2018-11-08T00:23:05Z

In some scenarios, the GRO engine can assemble an UDP GRO packet that ultimately lands on a non GRO-enabled socket. This patch tries to address the issue explicitly checking for the UDP socket features before enqueuing the packet, and eventually segmenting the unexpected GRO packet, as needed. We must also cope with re-insertion requests: after segmentation the UDP code calls the helper introduced by the previous patches, as needed. Segmentation is performed by a common helper, which takes care of updating socket and protocol stats is case of failure. rfc v3 -> v1 - fix compile issues with rxrpc - when gso_segment returns NULL, treat is as an error - added 'ipv4' argument to udp_rcv_segment() rfc v2 -> rfc v3 - moved udp_rcv_segment() into net/udp.h, account errors to socket and ns, always return NULL or segs list Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller