8b3136bd30 refactor: replace CNode pointers by references within net_processing.{h,cpp} (Sebastian Falbesoner)
Pull request description:
This PR is inspired by a [recent code review comment](https://github.com/bitcoin/bitcoin/pull/19010#discussion_r426954791) on a PR that introduced new functions to the net_processing module. The point of the discussion was basically that whenever we pass something not by value (in the concrete example it was about `CNode*` and `CConnman*`) we should either use
* a pointer (```CType*```) with null pointer check or
* a reference (```CType&```)
To keep things simple, this PR for a first approach
* only tackles `CNode*` pointers
* only within the net_processing module, i.e. no changes that would need adaption in other modules
* keeps the names of the variables as they are
I'm aware that PRs like this are kind of a PITA to review, but I think the code quality would increase if we get rid of pointers without nullptr check -- bloating up the code by adding all the missing checks would be the worse alternative, in my opinion.
Possible follow-up PRs, in case this is received well:
* replace CNode pointers by references for net module
* replace CConnman pointers by references for net_processing module
* ...
ACKs for top commit:
MarcoFalke:
ACK 8b3136bd30🔻
practicalswift:
ACK 8b3136bd30
Tree-SHA512: 15b6a569ecdcb39341002b9f4e09b38ed4df077e3a3a50dfb1b72d98bdc9f9769c7c504f106456aa7748af8591af7bb836b72d46086df715ab116e4ac3224b3b
fab860aed4 fuzz: Stop nodes in process_message* fuzzers (MarcoFalke)
6666c828e0 fuzz: Give CNode ownership to ConnmanTestMsg in process_message fuzz harness (MarcoFalke)
Pull request description:
Background is that I saw an integer overflow in net_processing
```
#30629113 REDUCE cov: 25793 ft: 142917 corp: 3421/2417Kb lim: 4096 exec/s: 89 rss: 614Mb L: 1719/4096 MS: 1 EraseBytes-
net_processing.cpp:977:25: runtime error: signed integer overflow: 2147483624 + 100 cannot be represented in type 'int'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior net_processing.cpp:977:25 in
net_processing.cpp:985:9: runtime error: signed integer overflow: -2147483572 - 100 cannot be represented in type 'int'
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior net_processing.cpp:985:9 in
```
Telling from the line numbers, it looks like `nMisbehavior` wrapped around.
Fix that by calling `StopNodes` after each exec, which should clear the node state and thus `nMisbehavior`.
ACKs for top commit:
practicalswift:
ACK fab860aed4
Tree-SHA512: 891c081d5843565d891aec028b6c27ef3fa39bc40ae78238e81d8f784b4d4b49cb870998574725a5159dd03aeeb2e0b9bc3d3bb51d57d1231ef42e3394b2d639
