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![Jan Engelhardt](/assets/img/avatar_default.png)
The static initial tables are pretty large, and after the net namespace has been instantiated, they just hang around for nothing. This commit removes them and creates tables on-demand at runtime when needed. Size shrinks by 7735 bytes (x86_64). Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
35 lines
1.2 KiB
C
35 lines
1.2 KiB
C
/*
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* Today's hack: quantum tunneling in structs
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*
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* 'entries' and 'term' are never anywhere referenced by word in code. In fact,
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* they serve as the hanging-off data accessed through repl.data[].
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*/
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#define xt_alloc_initial_table(type, typ2) ({ \
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unsigned int hook_mask = info->valid_hooks; \
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unsigned int nhooks = hweight32(hook_mask); \
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unsigned int bytes = 0, hooknum = 0, i = 0; \
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struct { \
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struct type##_replace repl; \
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struct type##_standard entries[nhooks]; \
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struct type##_error term; \
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} *tbl = kzalloc(sizeof(*tbl), GFP_KERNEL); \
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if (tbl == NULL) \
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return NULL; \
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strncpy(tbl->repl.name, info->name, sizeof(tbl->repl.name)); \
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tbl->term = (struct type##_error)typ2##_ERROR_INIT; \
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tbl->repl.valid_hooks = hook_mask; \
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tbl->repl.num_entries = nhooks + 1; \
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tbl->repl.size = nhooks * sizeof(struct type##_standard) + \
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sizeof(struct type##_error); \
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for (; hook_mask != 0; hook_mask >>= 1, ++hooknum) { \
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if (!(hook_mask & 1)) \
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continue; \
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tbl->repl.hook_entry[hooknum] = bytes; \
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tbl->repl.underflow[hooknum] = bytes; \
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tbl->entries[i++] = (struct type##_standard) \
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typ2##_STANDARD_INIT(NF_ACCEPT); \
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bytes += sizeof(struct type##_standard); \
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} \
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tbl; \
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})
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