This is a third draft of the first steps in implementing more general
"connection" tracking, as described at:
https://pad.passt.top/p/NewForwardingModel
This series changes the TCP connection table and hash table into a
more general flow table that can track other protocols as well. Each
flow uniformly keeps track of all the relevant addresses and ports,
which will allow for more robust control of NAT and port forwarding.
ICMP is converted to use the new flow table.
Caveats:
* We significantly increase the size of a connection/flow entry
- Can probably be mitigated, but I haven't investigated much yet
* We perform a number of extra getsockname() calls to know some of
the socket endpoints
- Haven't yet measured how much performance impact that has
- Can be mitigated in at least some cases, but again, haven't
tried yet
* UDP is not converted yet
Changes since v2:
* Cosmetic fixes based on review
* Extra doc comments for enum flow_type
* Rename flowside to flowaddrs which turns out to make more sense in
light of future changes
* Fix bug where the socket flowaddrs for tap initiated connections
wasn't initialised to match the socket address we were using in the
case of map-gw NAT
* New flowaddrs_from_sock() helper used in most cases which is cleaner
and should avoid bugs like the above
* Using newer centralised workarounds for clang-tidy issue 58992
* Remove duplicate definition of FLOW_MAX as maximum flow type and
maximum number of tracked flows
* Rebased on newer versions of preliminary work (ICMP, flow based
dispatch and allocation, bind/address cleanups)
* Unified hash table as well as base flow table
* Integrated ICMP
Changes since v1:
* Terminology changes
- "Endpoint" address/port instead of "correspondent" address/port
- "flowside" instead of "demiflow"
* Actually move the connection table to a new flow table structure in
new files
* Significant rearrangement of earlier patchs on top of that new
table, to reduce churn
David Gibson (15):
flow: Common data structures for tracking flow addresses
tcp, flow: Maintain guest side flow information
tcp, flow: Maintain host side flow information
tcp_splice,flow: Maintain flow information for spliced connections
flow, tcp, tcp_splice: Uniform debug helpers for new flows
tcp, flow: Replace TCP specific hash function with general flow hash
flow: Add helper to determine a flow's protocol
flow, tcp: Generalise TCP hash table to general flow hash table
tcp: Re-use flow hash for initial sequence number generation
icmp: Store ping socket information in the flow table
icmp: Populate guest side information for ping flows
icmp: Populate and use host side flow information
icmp: Use 'flowside' epoll references for ping sockets
icmp: Merge EPOLL_TYPE_ICMP and EPOLL_TYPE_ICMPV6
icmp: Eliminate icmp_id_map
Makefile | 6 +-
flow.c | 260 ++++++++++++++++++++++++++++++++++++++++++
flow.h | 104 +++++++++++++++++
flow_table.h | 2 +
icmp.c | 211 +++++++++++++++++++---------------
icmp.h | 15 +--
icmp_flow.h | 31 +++++
passt.c | 15 +--
passt.h | 9 +-
tap.c | 11 --
tap.h | 1 -
tcp.c | 313 +++++++++++++++------------------------------------
tcp_conn.h | 9 --
tcp_splice.c | 63 ++++++++---
tcp_splice.h | 3 +-
util.c | 4 +-
util.h | 18 +++
17 files changed, 683 insertions(+), 392 deletions(-)
create mode 100644 icmp_flow.h
--
2.43.0