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Rework IP encapsulation handling code.

Description

Rework IP encapsulation handling code.

Currently it has several disadvantages:

  • it uses single mutex to protect internal structures. It is used by data- and control- path, thus there are no parallelism at all.
  • it uses single list to keep encap handlers for both INET and INET6 families.
  • struct encaptab keeps unneeded information (src, dst, masks, protosw), that isn't used by code in the source tree.
  • matches are prioritized and when many tunneling interfaces are registered, encapcheck handler of each interface is invoked for each packet. The search takes O(n) for n interfaces. All this work is done with exclusive lock held.

What this patch includes:

  • the datapath is converted to be lockless using epoch(9) KPI.
  • struct encaptab now linked using CK_LIST.
  • all unused fields removed from struct encaptab. Several new fields addedr: min_length is the minimum packet length, that encapsulation handler expects to see; exact_match is maximum number of bits, that can return an encapsulation handler, when it wants to consume a packet.
  • IPv6 and IPv4 handlers are stored in separate lists;
  • added new "encap_lookup_t" method, that will be used later. It is targeted to speedup lookup of needed interface, when gif(4)/gre(4) have many interfaces.
  • the need to use protosw structure is eliminated. The only pr_input method was used from this structure, so I don't see the need to keep using it.
  • encap_input_t method changed to avoid using mbuf tags to store softc pointer. Now it is passed directly trough encap_input_t method. encap_getarg() funtions is removed.
  • all sockaddr structures and code that uses them removed. We don't have any code in the tree that uses them. All consumers use encap_attach_func() method, that relies on invoking of encapcheck() to determine the needed handler.
  • introduced struct encap_config, it contains parameters of encap handler that is going to be registered by encap_attach() function.
  • encap handlers are stored in lists ordered by exact_match value, thus handlers that need more bits to match will be checked first, and if encapcheck method returns exact_match value, the search will be stopped.
  • all current consumers changed to use new KPI.

Reviewed by: mmacy
Sponsored by: Yandex LLC
Differential Revision: https://reviews.freebsd.org/D15617

Details

Provenance
aeAuthored on Jun 5 2018, 8:51 PM
Parents
rG56009ba0ed67: Make Coverity more happy with r334545
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