Jan Engelhardt | e3eaa99 | 2009-06-17 22:14:54 +0200 | [diff] [blame] | 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 | }) |