BIND 10 #2269: Configuration parser for DHCPv6 server

[BIND 10 Development]

#2269: Configuration parser for DHCPv6 server
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                   Reporter:  tomek  |                 Owner:  tomek
                       Type:  task   |                Status:  accepted
                   Priority:         |             Milestone:  Sprint-
  medium                             |  DHCP-20121004
                  Component:         |            Resolution:
  dhcpconf                           |             Sensitive:  0
                   Keywords:         |           Sub-Project:  DHCP
            Defect Severity:  N/A    |  Estimated Difficulty:  0
Feature Depending on Ticket:         |           Total Hours:  0
        Add Hours to Ticket:  0      |
                  Internal?:  0      |
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Comment (by tomek):

 Ready for review.

 As the parser code is somewhat non-obvious, I've created some additional
 documentation for it. See Developer's Guide, DHCPv6 section (or
 dhcpv6.dox).

 Although the storage in CfgMgr fully supports triplets (min/default/max
 values), that is not yet supported in the configuration (only a single
 value is always used). As this is not requested (a bonus type of feature),
 it is not implemented now. That would require non-trivial changes in
 bindctl to support triplets (if we wanted to add new field that allowed
 either integer or integer/integer/integer syntax). Alternatively, it would
 require supporting 3 optional parameters with complicated logic, which
 parameter is mandatory and which is optional in a given case. That would
 also have to take inheritance into account.

 There used to be a single configuration parameter defined in spec file
 that allowed network interface name to be specified. Is now accepts list
 of interface names. Those values are still ignored as they were before.

 Some of the parsers can be reused for DHCPv4. Right now they are in
 src/bin/dhcp6, but they will likely to be moved to libdhcpsrv in
 src/lib/dhcp, so they could be shared.

 Current design (many classes defined in .cc) assumed that the parser code
 should not pollute headers. With the intention to move them to src/lib,
 that approach is likely to change. That will be done as part of #2270.

-- 
Ticket URL: <http://bind10.isc.org/ticket/2269#comment:2>
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