[CoreSNTP]Sntp deserialize response and Sntp_SendTimeRequest cbmc proofs #15
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Start development of the higher-layer part of the coreSNTP library that represents a "managed client" functionality by adding the Sntp_Init API to initialize an Sntp context.
This reverts commit 6f2017e.
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CBMC proof run for Sntp_DeserializeResponse PR #15 flags overflow issue in the calculateClockOffset function when assignining negative value to an unsigned integer. This PR refactors the implementation to avoid overflow flagging by: * Storing only positive subtraction values in unsigned integers * Assigning a large unsigned integer (i.e. >= 0x80000000) to signed integer by first using its negative value and then inversing the negation after the assignment to obtain the correct value. This PR also adds resiliency to the clock-offset calculation by adding check against overflow (i.e. when server and client times are more than 34 years apart) on the Client -> Server SNTP request send network path.
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This PR contains Sntp deserialize response and Sntp_SendTimeRequest cbmc proofs.