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  • only in /asuswrt-rt-n18u-9.0.0.4.380.2695/release/src-rt-6.x.4708/linux/linux-2.6.36/net/netfilter/
1/*
2 * Today's hack: quantum tunneling in structs
3 *
4 * 'entries' and 'term' are never anywhere referenced by word in code. In fact,
5 * they serve as the hanging-off data accessed through repl.data[].
6 */
7
8#define xt_alloc_initial_table(type, typ2) ({ \
9	unsigned int hook_mask = info->valid_hooks; \
10	unsigned int nhooks = hweight32(hook_mask); \
11	unsigned int bytes = 0, hooknum = 0, i = 0; \
12	struct { \
13		struct type##_replace repl; \
14		struct type##_standard entries[nhooks]; \
15		struct type##_error term; \
16	} *tbl = kzalloc(sizeof(*tbl), GFP_KERNEL); \
17	if (tbl == NULL) \
18		return NULL; \
19	strncpy(tbl->repl.name, info->name, sizeof(tbl->repl.name)); \
20	tbl->term = (struct type##_error)typ2##_ERROR_INIT;  \
21	tbl->repl.valid_hooks = hook_mask; \
22	tbl->repl.num_entries = nhooks + 1; \
23	tbl->repl.size = nhooks * sizeof(struct type##_standard) + \
24	                 sizeof(struct type##_error); \
25	for (; hook_mask != 0; hook_mask >>= 1, ++hooknum) { \
26		if (!(hook_mask & 1)) \
27			continue; \
28		tbl->repl.hook_entry[hooknum] = bytes; \
29		tbl->repl.underflow[hooknum]  = bytes; \
30		tbl->entries[i++] = (struct type##_standard) \
31			typ2##_STANDARD_INIT(NF_ACCEPT); \
32		bytes += sizeof(struct type##_standard); \
33	} \
34	tbl; \
35})
36