BGP external announcements: Create a BGP session properties objects for import policy evaluation

[ratulm]

This change helps evaluate routing policy statements that rely on the session object, such as set next hop peer address. The behavior prior to this change was to throw an exception when such statements were encountered.

[batfish-bot]

This change is 

[codecov]

Codecov Report

Merging #7230 (58a16cf) into master (0bcf0ef) will decrease coverage by 0.01%.
The diff coverage is 76.19%.

@@             Coverage Diff              @@
##             master    #7230      +/-   ##
============================================
- Coverage     72.77%   72.76%   -0.02%     
+ Complexity    38884    38875       -9     
============================================
  Files          3101     3101              
  Lines        156794   156808      +14     
  Branches      18814    18817       +3     
============================================
- Hits         114105   114099       -6     
- Misses        33671    33679       +8     
- Partials       9018     9030      +12     

Impacted Files	Coverage Δ
.../org/batfish/dataplane/ibdp/BgpRoutingProcess.java	83.50% <75.00%> (-0.18%)	⬇️
...atfish/datamodel/routing_policy/RoutingPolicy.java	94.68% <100.00%> (ø)
...g/batfish/datamodel/flow/IncomingSessionScope.java	84.61% <0.00%> (-15.39%)	⬇️
.../datamodel/routing_policy/statement/Statement.java	72.72% <0.00%> (-9.10%)	⬇️
...batfish/representation/aws/LoadBalancerTarget.java	54.16% <0.00%> (-4.17%)	⬇️
...org/batfish/datamodel/flow/BidirectionalTrace.java	81.81% <0.00%> (-2.28%)	⬇️
...col/src/main/java/org/batfish/role/InferRoles.java	91.36% <0.00%> (-1.37%)	⬇️
...src/main/java/org/batfish/coordinator/PoolMgr.java	59.52% <0.00%> (-1.20%)	⬇️
...java/org/batfish/dataplane/ibdp/VirtualRouter.java	89.84% <0.00%> (-0.31%)	⬇️
...src/main/java/org/batfish/coordinator/WorkMgr.java	75.96% <0.00%> (-0.16%)	⬇️
... and 1 more

[dhalperi]

Reviewable status: 0 of 3 files reviewed, 1 unresolved discussion (waiting on @ratulm)

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projects/batfish-common-protocol/src/main/java/org/batfish/datamodel/routing_policy/RoutingPolicy.java, line 236 at r1 (raw file):

  /** @return True if the policy accepts the route. */
  public boolean process(

is there a reason you can't use processBgpRoute?

[dhalperi]

Reviewable status: 0 of 3 files reviewed, 2 unresolved discussions (waiting on @ratulm)

a discussion (no related file):
Need some test from configs and advertisements, to make sure it works.

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[ratulm]

Reviewable status: 0 of 3 files reviewed, 2 unresolved discussions (waiting on @dhalperi and @ratulm)

a discussion (no related file):

Previously, dhalperi (Dan Halperin) wrote…

Need some test from configs and advertisements, to make sure it works.

Separate PR: https://github.com/batfish/batfish/pull/7231/files

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[dhalperi]

Reviewed 1 of 3 files at r1, 2 of 2 files at r2, all commit messages.
Reviewable status: complete! all files reviewed, all discussions resolved (waiting on @ratulm)