Add IPv6 support to BPF rate limit #1458
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The in-BPF message rate limit specified that the maximum number of bytes per argument included had to be a power of 2 as we used 1 less than that amount as a mask to limit the size of a parameter. Two problems emerge from this restriction: first, we might want a max number of bytes per argument that is not a power of 2 – given we multiply this by 5 and then use this in a hash key, forcing a power of 2 could have significant effects on the volume of bytes being hashed - and second, the use of the mask actually reduced the maximum number of bytes by 1, which is a bit annoying. This commit reworks the code slightly to remove these two problems. Signed-off-by: Kevin Sheldrake <kevin.sheldrake@isovalent.com>
The original in-BPF message rate limit only supported IPv4 as we didn't have IPv6 support in general. Now we do. This commit adds extra space to the rate limit key so that it can support an IPv6 tuple. Signed-off-by: Kevin Sheldrake <kevin.sheldrake@isovalent.com>
kevsecurity
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jrfastab
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Sep 18, 2023
| __uint(max_entries, 1); | ||
| __type(key, __u32); | ||
| __type(value, __u8[sizeof(struct ratelimit_key) + 128]); | ||
| } ratelimit_ro_heap SEC(".maps"); |
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would be nice to preface with tg_ratelimit_ro_heap and above so that bpftool reports them with tetragon 'tg' map preface. Not sure we have hit all the maps yet with the naming convention but will be nice going forward.
jrfastab
approved these changes
Sep 18, 2023
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See commits.
First commit fixes a couple of (pseudo?) bugs in the in-BPF rate limit code. It worked before, but it wasn't optimal.
Second commit adds support for IPv6 tuples so that rate limiting isn't just limited to IPv4.