mbox series

[bpf-next,v3,0/3] Add FOU support for externally controlled ipip devices

Message ID cover.1680874078.git.cehrig@cloudflare.com
Headers
Series Add FOU support for externally controlled ipip devices |

Message

Christian Ehrig April 7, 2023, 1:38 p.m. UTC 
  This patch set adds support for using FOU or GUE encapsulation with
an ipip device operating in collect-metadata mode and a set of kfuncs
for controlling encap parameters exposed to a BPF tc-hook.

BPF tc-hooks allow us to read tunnel metadata (like remote IP addresses)
in the ingress path of an externally controlled tunnel interface via
the bpf_skb_get_tunnel_{key,opt} bpf-helpers. Packets can then be
redirected to the same or a different externally controlled tunnel
interface by overwriting metadata via the bpf_skb_set_tunnel_{key,opt}
helpers and a call to bpf_redirect. This enables us to redirect packets
between tunnel interfaces - and potentially change the encapsulation
type - using only a single BPF program.

Today this approach works fine for a couple of tunnel combinations.
For example: redirecting packets between Geneve and GRE interfaces or
GRE and plain ipip interfaces. However, redirecting using FOU or GUE is
not supported today. The ip_tunnel module does not allow us to egress
packets using additional UDP encapsulation from an ipip device in
collect-metadata mode.

Patch 1 lifts this restriction by adding a struct ip_tunnel_encap to
the tunnel metadata. It can be filled by a new BPF kfunc introduced
in Patch 2 and evaluated by the ip_tunnel egress path. This will allow
us to use FOU and GUE encap with externally controlled ipip devices.

Patch 2 introduces two new BPF kfuncs: bpf_skb_{set,get}_fou_encap.
These helpers can be used to set and get UDP encap parameters from the
BPF tc-hook doing the packet redirect.

Patch 3 adds BPF tunnel selftests using the two kfuncs.

---
v3:
 - Integrate selftest into test_progs (Alexei)
v2:
 - Fixes for checkpatch.pl
 - Fixes for kernel test robot

Christian Ehrig (3):
  ipip,ip_tunnel,sit: Add FOU support for externally controlled ipip
    devices
  bpf,fou: Add bpf_skb_{set,get}_fou_encap kfuncs
  selftests/bpf: Test FOU kfuncs for externally controlled ipip devices

 include/net/fou.h                             |   2 +
 include/net/ip_tunnels.h                      |  28 ++--
 net/ipv4/Makefile                             |   2 +-
 net/ipv4/fou_bpf.c                            | 119 ++++++++++++++
 net/ipv4/fou_core.c                           |   5 +
 net/ipv4/ip_tunnel.c                          |  22 ++-
 net/ipv4/ipip.c                               |   1 +
 net/ipv6/sit.c                                |   2 +-
 .../selftests/bpf/prog_tests/test_tunnel.c    | 153 +++++++++++++++++-
 .../selftests/bpf/progs/test_tunnel_kern.c    | 117 ++++++++++++++
 10 files changed, 432 insertions(+), 19 deletions(-)
 create mode 100644 net/ipv4/fou_bpf.c

Comments

patchwork-bot+netdevbpf@kernel.org April 12, 2023, 11:50 p.m. UTC | #1 
Hello:

This series was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Fri,  7 Apr 2023 15:38:52 +0200 you wrote:
> This patch set adds support for using FOU or GUE encapsulation with
> an ipip device operating in collect-metadata mode and a set of kfuncs
> for controlling encap parameters exposed to a BPF tc-hook.
> 
> BPF tc-hooks allow us to read tunnel metadata (like remote IP addresses)
> in the ingress path of an externally controlled tunnel interface via
> the bpf_skb_get_tunnel_{key,opt} bpf-helpers. Packets can then be
> redirected to the same or a different externally controlled tunnel
> interface by overwriting metadata via the bpf_skb_set_tunnel_{key,opt}
> helpers and a call to bpf_redirect. This enables us to redirect packets
> between tunnel interfaces - and potentially change the encapsulation
> type - using only a single BPF program.
> 
> [...]

Here is the summary with links:
  - [bpf-next,v3,1/3] ipip,ip_tunnel,sit: Add FOU support for externally controlled ipip devices
    https://git.kernel.org/bpf/bpf-next/c/ac931d4cdec3
  - [bpf-next,v3,2/3] bpf,fou: Add bpf_skb_{set,get}_fou_encap kfuncs
    https://git.kernel.org/bpf/bpf-next/c/c50e96099edb
  - [bpf-next,v3,3/3] selftests/bpf: Test FOU kfuncs for externally controlled ipip devices
    https://git.kernel.org/bpf/bpf-next/c/d9688f898c08

You are awesome, thank you!