Skip to content

Commit

Permalink
Fix formatting.
Browse files Browse the repository at this point in the history
  • Loading branch information
gamemann committed May 22, 2024
1 parent bfc3886 commit 4e3a1c9
Showing 1 changed file with 1 addition and 1 deletion.
2 changes: 1 addition & 1 deletion README.md
Original file line number Diff line number Diff line change
Expand Up @@ -14,7 +14,7 @@
#### Note Regarding Seeding/Randomness
When generating randomness in a packet (e.g. random source IPs, ports, payload(s), etc.), by default, we try to use nanoseconds since boot using `timespec` as the seed when passing to `[rand_r()]`(https://linux.die.net/man/3/rand_r) for example. However, I've found this isn't completely random, especially since the seed variable (`unsigned int`) and `timespec` nanoseconds variable (`long`) do not match in size.

Therefore, I added the constant [`VERY_RANDOM`](https://github.com/Packet-Batch/PB-AF-XDP/blob/master/src/sequence.h#L36) that can be uncommented. When this constant is defined, the `[getrandom()]`(https://man7.org/linux/man-pages/man2/getrandom.2.html) function is used to fill the seed with random bytes. This results in more randomness, but the `getrandom()` function adds a bit more overhead than retrieving the nanoseconds since system boot from my testing.
Therefore, I added the constant [`VERY_RANDOM`](https://github.com/Packet-Batch/PB-AF-XDP/blob/master/src/sequence.h#L36) that can be uncommented. When this constant is defined, the [`getrandom()`](https://man7.org/linux/man-pages/man2/getrandom.2.html) function is used to fill the seed with random bytes. This results in more randomness, but the `getrandom()` function adds a bit more overhead than retrieving the nanoseconds since system boot from my testing.

### Disclaimer
I do **NOT** support using these tools maliciously or as a part of a targeted attack. I've made these tools to perform penetration tests against my own firewalls along with occasionally debugging network issues such as packets not arriving to their destination correctly.
Expand Down

0 comments on commit 4e3a1c9

Please sign in to comment.