Count Blocked Rate-Limited Requests

You are given an in-memory log of web requests, already sorted by timestamp in ascending order. Each log entry contains:

• timestamp: An ISO-8601 UTC timestamp.
• request_ip: The client's IPv4 address.
• host: The hostname being requested.

You may assume the entire log fits into memory.

A request is evaluated against a sliding window of T seconds. For a request occurring at time t, only earlier requests with timestamps strictly within the interval (t - T, t) are considered. Requests that occurred exactly T seconds earlier are not included in the window.

Important Rules:

• A request that is blocked must still be counted in the history for future rate-limiting evaluations.
• If multiple requests share the same timestamp, they should be processed in their given input order.
• If a request violates multiple rate-limiting rules (in Part 2), it should be counted as a single blocked request, not multiple.

Part 1: Per-IP Rate Limiting

Implement logic to count the total number of requests that would be blocked by the following rule:

• A request from IP x is blocked if there have already been at least IPReqMax requests from the same IP within the previous T seconds.

Formally, the current request is blocked when: count(previous requests from the same IP in (t - T, t)) >= IPReqMax

Example for Part 1

Input log:

timestamp,request_ip,host
2024-01-01T00:00:00+00:00,127.0.0.1,example1.com
2024-01-01T00:00:01+00:00,127.0.0.1,example2.com
2024-01-01T00:01:02+00:00,127.0.0.1,example1.com
2024-01-01T00:01:03+00:00,127.0.0.1,example2.com
2024-01-01T00:01:04+00:00,127.0.0.1,example1.com
2024-01-01T00:02:04+00:00,127.0.0.1,example1.com

With IPReqMax = 1 and T = 60:

• Request 1 (00:00:00) -> succeed
• Request 2 (00:00:01) -> blocked
• Request 3 (00:01:02) -> succeed
• Request 4 (00:01:03) -> blocked
• Request 5 (00:01:04) -> blocked
• Request 6 (00:02:04) -> succeed

Total blocked requests: 3.

Part 2: Per-IP and Per-(IP, Host) Rate Limiting

Now, an additional rule is introduced:

• A request from IP x to host h is also blocked if there have already been at least IPHostReqMax requests from the same IP to the same host within the previous T seconds.

A request is considered blocked if either of these conditions is true:

1. count(previous requests from the same IP in (t - T, t)) >= IPReqMax
2. count(previous requests from the same IP and same host in (t - T, t)) >= IPHostReqMax

As before, blocked requests still contribute to both counters for future evaluations.

Example for Part 2

Input log:

timestamp,request_ip,host
2024-01-01T00:00:00+00:00,127.0.0.1,example1.com
2024-01-01T00:00:01+00:00,127.0.0.1,example2.com
2024-01-01T00:00:10+00:00,127.0.0.1,example1.com
2024-01-01T00:00:11+00:00,127.0.0.1,example3.com
2024-01-01T00:01:04+00:00,127.0.0.1,example3.com
2024-01-01T00:01:11+00:00,127.0.0.1,example1.com

With IPReqMax = 3, IPHostReqMax = 1, and T = 60:

• Request 1 (00:00:00, 127.0.0.1, example1.com) -> succeed
• Request 2 (00:00:01, 127.0.0.1, example2.com) -> succeed
• Request 3 (00:00:10, 127.0.0.1, example1.com) -> blocked by per-(IP, host) rule
• Request 4 (00:00:11, 127.0.0.1, example3.com) -> blocked by per-IP rule
• Request 5 (00:01:04, 127.0.0.1, example3.com) -> blocked by per-(IP, host) rule
• Request 6 (00:01:11, 127.0.0.1, example1.com) -> succeed

Total blocked requests: 3.

Task

Your goal is to write an efficient function or program that, given the sorted request log and the parameters T, IPReqMax, and optionally IPHostReqMax, returns:

1. The total number of blocked requests under the per-IP rule only (Part 1).
2. The total number of blocked requests under the combined per-IP and per-(IP, host) rules (Part 2).

The solution should be efficient for large logs that fit into memory.