[P4TC] Align key components to the nearest 8-bit size #5024
+3,232
−397
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Signed-off-by: Komal, Jain <[email protected]>
vbnogueira
reviewed
Nov 21, 2024
| u32 select_0; | ||
| select_0 = (((((u32)(((u16)tmp_0.p << 8) | ((u16)tmp_2.four & 0xff)) << 8) & ((1 << 24) - 1)) | (((u32)tmp_4.ver & 0xff) & ((1 << 24) - 1))) & ((1 << 24) - 1)); | ||
| u8 select_0[3]; | ||
| storePrimitive32((u8 *)&select_0, 24, ((((((u32)(((u16)tmp_0.p << 8) | ((u16)tmp_2.four & 0xff)) << 8) & ((1 << 24) - 1)) | (((u32)tmp_4.ver & 0xff) & ((1 << 24) - 1))) & ((1 << 24) - 1)))); | ||
| if (select_0 == 0x503401)goto parse_p4calc; |
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In this case I think you need to convert select_0 back to a u32 or do a byte by byte comparison.
Since select_0 is a u8 array, the compiler is complaining
| @@ -56,3 +56,48 @@ REGISTER_TABLE(hdr_md_cpumap, BPF_MAP_TYPE_PERCPU_ARRAY, u32, struct hdr_md, 2) | |||
| BPF_ANNOTATE_KV_PAIR(hdr_md_cpumap, u32, struct hdr_md) | |||
| REGISTER_END() | |||
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| u32 getPrimitive32(u8 *a, int size) { | |||
| if(size <=32 || size >=56) { | |||
| error("Invalid size."); | |||
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The compiler is complaining about this also
warning: call to undeclared function 'error'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
error("Invalid size.");
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As of now, whenever there is a key component that is a bit-type which doesn't correspond to primitive C type (u8, u16, u32, ...),
the compiler generates it as using the closest primitive C type that is larger then X in bit
For example -
dest_op here is converted into u32 like below -
This won't work, because the P4TC side is expecting the bit<24> (
dest_op) to be contained in3 bytesand not 4. All key components are expected to be 8-bit aligned. The new declaration for 'dest_op' would be -For all operations, compiler will call function 'getPrimitiveXX()' which will convert u8[] into primitive type (u32 or u64).
For reverse assignment operations compiler calls 'storePrimitiveXX()' which converts primitive types to u8 [ ] array.
@vbnogueira @jhsmt