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[net-next,v2,00/12] flow_dissector: Dissect UDP encapsulation protocols

Message ID 20240815214527.2100137-1-tom@herbertland.com (mailing list archive)
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Series flow_dissector: Dissect UDP encapsulation protocols | expand

Message

Tom Herbert Aug. 15, 2024, 9:45 p.m. UTC 
Add support in flow_dissector for dissecting into UDP
encapsulations like VXLAN. __skb_flow_dissect_udp is called for
IPPROTO_UDP. The flag FLOW_DISSECTOR_F_PARSE_UDP_ENCAPS enables parsing
of UDP encapsulations. If the flag is set when parsing a UDP packet then
a socket lookup is performed. The offset of the base network header,
either an IPv4 or IPv6 header, is tracked and passed to
__skb_flow_dissect_udp so that it can perform the socket lookup.
If a socket is found and it's for a UDP encapsulation (encap_type is
set in the UDP socket) then a switch is performed on the encap_type
value (cases are UDP_ENCAP_* values)

Changes in the patch set:

- Unconstantify struct net argument in flowdis functions so we can call
  UDP socket lookup functions
- Dissect ETH_P_TEB in main flow dissector loop, move ETH_P_TEB check
  out of __skb_flow_dissect_gre and process it in main loop
- Add UDP_ENCAP constants for tipc, fou, gue, sctp, rxe, pfcp,
  wireguard, bareudp, vxlan, vxlan_gpe, geneve, and amt
- For the various UDP encapsulation protocols, Instead of just setting
  UDP tunnel encap type to 1, set it to the corresponding UDP_ENCAP
  constant. This allows identify the encapsulation protocol for a
  UDP socket by the encap_type
- Add function __skb_flow_dissect_udp in flow_dissector and call it for
  UDP packets. If a UDP encapsulation is present then the function
  returns either FLOW_DISSECT_RET_PROTO_AGAIN or
  FLOW_DISSECT_RET_IPPROTO_AGAIN
- Add flag FLOW_DISSECTOR_F_PARSE_UDP_ENCAPS that indicates UDP
  encapsulations should be dissected
- Add __skb_flow_dissect_vxlan which is called when encap_type is
  UDP_ENCAP_VXLAN or UDP_ENCAP_VXLAN_GPE. Dissect VXLAN and return
  a next protocol and offset
- Add __skb_flow_dissect_fou which is called when encap_type is
  UDP_ENCAP_FOU. Dissect FOU and return a next protocol and offset
- Add support for ESP, L2TP, and SCTP in UDP in __skb_flow_dissect_udp.
  All we need to do is return FLOW_DISSECT_RET_IPPROTO_AGAIN and the
  corresponding IP protocol number
- Add __skb_flow_dissect_geneve which is called when encap_type is
  UDP_ENCAP_GENEVE. Dissect geneve and return a next protocol and offset
- Add __skb_flow_dissect_gue which is called when encap_type is
  UDP_ENCAP_GUE. Dissect gue and return a next protocol and offset
- Add __skb_flow_dissect_gtp which is called when encap_type is
  UDP_ENCAP_GTP. Dissect gtp and return a next protocol and offset

Tested: Verified fou, gue, vxlan, and geneve are properly dissected for
IPv4 and IPv6 cases. This includes testing ETH_P_TEB case

v2:
- Add #if IS_ENABLED(CONFIG_IPV6) around IPv6 cases when dissecting UDP.
  Also, c all ipv6_bpf_stub->udp6_lib_lookup instead of udp6_lib_lookup
  directly since udp6_lib_lookup in the IPv6 module
- Drop patch to unconstantify struct net argument in flowdis functions,
  edumazet added const to ne argument in UDP socket lookup functions
- As support in flowdis ipproto switch for no-next-hdr. Just exit
  flowdis on good result when this is seen
- Merge patches that move TEB processing out of GRE and moved into
  main protocol switch
- Rename bpoff in UDP flow dissector functions to be base_nhoff for
  clarity
- Parse GTPv1 extension headers (part of this is moving
  gtp_parse_exthdrs to a header file
- Exit flowdis on good result if NPDU or SEQ GTPv1 flags are set


Tom Herbert (12):
  flow_dissector: Parse ETH_P_TEB and move out of GRE
  udp_encaps: Add new UDP_ENCAP constants
  udp_encaps: Set proper UDP_ENCAP types in tunnel setup
  flow_dissector: UDP encap infrastructure
  flow_dissector: Parse vxlan in UDP
  flow_dissector: Parse foo-over-udp (FOU)
  flow_dissector: Parse ESP, L2TP, and SCTP in UDP
  flow_dissector: Parse Geneve in UDP
  flow_dissector: Parse GUE in UDP
  gtp: Move gtp_parse_exthdrs into net/gtp.h
  flow_dissector: Parse gtp in UDP
  flow_dissector: Add case in ipproto switch for NEXTHDR_NONE

 drivers/infiniband/sw/rxe/rxe_net.c |   2 +-
 drivers/net/amt.c                   |   2 +-
 drivers/net/bareudp.c               |   2 +-
 drivers/net/geneve.c                |   2 +-
 drivers/net/gtp.c                   |  37 ---
 drivers/net/pfcp.c                  |   2 +-
 drivers/net/vxlan/vxlan_core.c      |   3 +-
 drivers/net/wireguard/socket.c      |   2 +-
 include/net/flow_dissector.h        |   1 +
 include/net/fou.h                   |  16 +
 include/net/gtp.h                   |  38 +++
 include/uapi/linux/udp.h            |  13 +
 net/core/flow_dissector.c           | 448 ++++++++++++++++++++++++++--
 net/ipv4/fou_core.c                 |  19 +-
 net/sctp/protocol.c                 |   2 +-
 net/tipc/udp_media.c                |   2 +-
 16 files changed, 502 insertions(+), 89 deletions(-)

Comments

Willem de Bruijn Aug. 16, 2024, 8:19 p.m. UTC | #1 
Tom Herbert wrote:
> Add support in flow_dissector for dissecting into UDP
> encapsulations like VXLAN. __skb_flow_dissect_udp is called for
> IPPROTO_UDP. The flag FLOW_DISSECTOR_F_PARSE_UDP_ENCAPS enables parsing
> of UDP encapsulations. If the flag is set when parsing a UDP packet then
> a socket lookup is performed. The offset of the base network header,
> either an IPv4 or IPv6 header, is tracked and passed to
> __skb_flow_dissect_udp so that it can perform the socket lookup.
> If a socket is found and it's for a UDP encapsulation (encap_type is
> set in the UDP socket) then a switch is performed on the encap_type
> value (cases are UDP_ENCAP_* values)
> 
> Changes in the patch set:
> 
> - Unconstantify struct net argument in flowdis functions so we can call
>   UDP socket lookup functions
> - Dissect ETH_P_TEB in main flow dissector loop, move ETH_P_TEB check
>   out of __skb_flow_dissect_gre and process it in main loop
> - Add UDP_ENCAP constants for tipc, fou, gue, sctp, rxe, pfcp,
>   wireguard, bareudp, vxlan, vxlan_gpe, geneve, and amt
> - For the various UDP encapsulation protocols, Instead of just setting
>   UDP tunnel encap type to 1, set it to the corresponding UDP_ENCAP
>   constant. This allows identify the encapsulation protocol for a
>   UDP socket by the encap_type
> - Add function __skb_flow_dissect_udp in flow_dissector and call it for
>   UDP packets. If a UDP encapsulation is present then the function
>   returns either FLOW_DISSECT_RET_PROTO_AGAIN or
>   FLOW_DISSECT_RET_IPPROTO_AGAIN
> - Add flag FLOW_DISSECTOR_F_PARSE_UDP_ENCAPS that indicates UDP
>   encapsulations should be dissected
> - Add __skb_flow_dissect_vxlan which is called when encap_type is
>   UDP_ENCAP_VXLAN or UDP_ENCAP_VXLAN_GPE. Dissect VXLAN and return
>   a next protocol and offset
> - Add __skb_flow_dissect_fou which is called when encap_type is
>   UDP_ENCAP_FOU. Dissect FOU and return a next protocol and offset
> - Add support for ESP, L2TP, and SCTP in UDP in __skb_flow_dissect_udp.
>   All we need to do is return FLOW_DISSECT_RET_IPPROTO_AGAIN and the
>   corresponding IP protocol number
> - Add __skb_flow_dissect_geneve which is called when encap_type is
>   UDP_ENCAP_GENEVE. Dissect geneve and return a next protocol and offset
> - Add __skb_flow_dissect_gue which is called when encap_type is
>   UDP_ENCAP_GUE. Dissect gue and return a next protocol and offset
> - Add __skb_flow_dissect_gtp which is called when encap_type is
>   UDP_ENCAP_GTP. Dissect gtp and return a next protocol and offset
> 
> Tested: Verified fou, gue, vxlan, and geneve are properly dissected for
> IPv4 and IPv6 cases. This includes testing ETH_P_TEB case

On our conversation in v1 that this is manual:

Would be really nice to have some test coverage for flow dissection.
We only have this for BPF flow dissection. This seems like a suitable
candidate for KUNIT. Like gso_test_func. Don't mean to put you on the
spot per se to add this coverage.
Tom Herbert Aug. 20, 2024, 6:28 p.m. UTC | #2 
On Fri, Aug 16, 2024 at 1:19 PM Willem de Bruijn
<willemdebruijn.kernel@gmail.com> wrote:
>
> Tom Herbert wrote:
> > Add support in flow_dissector for dissecting into UDP
> > encapsulations like VXLAN. __skb_flow_dissect_udp is called for
> > IPPROTO_UDP. The flag FLOW_DISSECTOR_F_PARSE_UDP_ENCAPS enables parsing
> > of UDP encapsulations. If the flag is set when parsing a UDP packet then
> > a socket lookup is performed. The offset of the base network header,
> > either an IPv4 or IPv6 header, is tracked and passed to
> > __skb_flow_dissect_udp so that it can perform the socket lookup.
> > If a socket is found and it's for a UDP encapsulation (encap_type is
> > set in the UDP socket) then a switch is performed on the encap_type
> > value (cases are UDP_ENCAP_* values)
> >
> > Changes in the patch set:
> >
> > - Unconstantify struct net argument in flowdis functions so we can call
> >   UDP socket lookup functions
> > - Dissect ETH_P_TEB in main flow dissector loop, move ETH_P_TEB check
> >   out of __skb_flow_dissect_gre and process it in main loop
> > - Add UDP_ENCAP constants for tipc, fou, gue, sctp, rxe, pfcp,
> >   wireguard, bareudp, vxlan, vxlan_gpe, geneve, and amt
> > - For the various UDP encapsulation protocols, Instead of just setting
> >   UDP tunnel encap type to 1, set it to the corresponding UDP_ENCAP
> >   constant. This allows identify the encapsulation protocol for a
> >   UDP socket by the encap_type
> > - Add function __skb_flow_dissect_udp in flow_dissector and call it for
> >   UDP packets. If a UDP encapsulation is present then the function
> >   returns either FLOW_DISSECT_RET_PROTO_AGAIN or
> >   FLOW_DISSECT_RET_IPPROTO_AGAIN
> > - Add flag FLOW_DISSECTOR_F_PARSE_UDP_ENCAPS that indicates UDP
> >   encapsulations should be dissected
> > - Add __skb_flow_dissect_vxlan which is called when encap_type is
> >   UDP_ENCAP_VXLAN or UDP_ENCAP_VXLAN_GPE. Dissect VXLAN and return
> >   a next protocol and offset
> > - Add __skb_flow_dissect_fou which is called when encap_type is
> >   UDP_ENCAP_FOU. Dissect FOU and return a next protocol and offset
> > - Add support for ESP, L2TP, and SCTP in UDP in __skb_flow_dissect_udp.
> >   All we need to do is return FLOW_DISSECT_RET_IPPROTO_AGAIN and the
> >   corresponding IP protocol number
> > - Add __skb_flow_dissect_geneve which is called when encap_type is
> >   UDP_ENCAP_GENEVE. Dissect geneve and return a next protocol and offset
> > - Add __skb_flow_dissect_gue which is called when encap_type is
> >   UDP_ENCAP_GUE. Dissect gue and return a next protocol and offset
> > - Add __skb_flow_dissect_gtp which is called when encap_type is
> >   UDP_ENCAP_GTP. Dissect gtp and return a next protocol and offset
> >
> > Tested: Verified fou, gue, vxlan, and geneve are properly dissected for
> > IPv4 and IPv6 cases. This includes testing ETH_P_TEB case
>
> On our conversation in v1 that this is manual:
>
> Would be really nice to have some test coverage for flow dissection.
> We only have this for BPF flow dissection. This seems like a suitable
> candidate for KUNIT. Like gso_test_func. Don't mean to put you on the
> spot per se to add this coverage.

Sure. We'll add a KUNIT test for flow dissector (it sorely needs that!)

Tom