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Filter: Recursive filter iteration code

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Add macros for recursive filter iteration that allows to examine
all instructions reachable from a filter.
This commit is contained in:
Ondrej Zajicek (work) 2021-02-07 19:21:42 +01:00
parent 5d414309ec
commit d06a875b04
7 changed files with 109 additions and 0 deletions
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1
filter/data.h
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@ -175,6 +175,7 @@ struct f_tree *build_tree(struct f_tree *);
const struct f_tree *find_tree(const struct f_tree *t, const struct f_val *val);
int same_tree(const struct f_tree *t0, const struct f_tree *t2);
void tree_format(const struct f_tree *t, buffer *buf);
void tree_walk(const struct f_tree *t, void (*hook)(const struct f_tree *, void *), void *data);
struct f_trie *f_new_trie(linpool *lp, uint data_size);
void *trie_add_prefix(struct f_trie *t, const net_addr *n, uint l, uint h);

34
filter/decl.m4
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@ -40,6 +40,7 @@ m4_divert(-1)m4_dnl
# 106 comparator body
# 107 struct f_line_item content
# 108 interpreter body
# 109 iterator body
#
# Here are macros to allow you to _divert to the right directions.
m4_define(FID_STRUCT_IN, `m4_divert(101)')
@ -50,6 +51,7 @@ m4_define(FID_LINEARIZE_BODY, `m4_divert(105)')
m4_define(FID_SAME_BODY, `m4_divert(106)')
m4_define(FID_LINE_IN, `m4_divert(107)')
m4_define(FID_INTERPRET_BODY, `m4_divert(108)')
m4_define(FID_ITERATE_BODY, `m4_divert(109)')
# Sometimes you want slightly different code versions in different
# outputs.
@ -211,6 +213,8 @@ FID_LINEARIZE_BODY()m4_dnl
item->fl$1 = f_linearize(whati->f$1);
FID_SAME_BODY()m4_dnl
if (!f_same(f1->fl$1, f2->fl$1)) return 0;
FID_ITERATE_BODY()m4_dnl
if (whati->fl$1) BUFFER_PUSH(fit->lines) = whati->fl$1;
FID_INTERPRET_EXEC()m4_dnl
do { if (whati->fl$1) {
LINEX_(whati->fl$1);
@ -265,6 +269,7 @@ m4_define(ACCESS_RTE, `FID_HIC(,[[do { if (!fs->rte) runtime("No route to access
# 7 dump line item callers
# 8 linearize
# 9 same (filter comparator)
# 10 iterate
# 1 union in struct f_inst
# 3 constructors + interpreter
#
@ -285,6 +290,7 @@ m4_define(FID_DUMP, `FID_ZONE(6, Dump line)')
m4_define(FID_DUMP_CALLER, `FID_ZONE(7, Dump line caller)')
m4_define(FID_LINEARIZE, `FID_ZONE(8, Linearize)')
m4_define(FID_SAME, `FID_ZONE(9, Comparison)')
m4_define(FID_ITERATE, `FID_ZONE(10, Iteration)')
# This macro does all the code wrapping. See inline comments.
m4_define(INST_FLUSH, `m4_ifdef([[INST_NAME]], [[
@ -372,6 +378,13 @@ m4_undivert(106)m4_dnl
#undef f2
break;
FID_ITERATE()m4_dnl The iterator
case INST_NAME():
#define whati (&(what->i_]]INST_NAME()[[))
m4_undivert(109)m4_dnl
#undef whati
break;
m4_divert(-1)FID_FLUSH(101,200)m4_dnl And finally this flushes all the unused diversions
]])')
@ -582,6 +595,27 @@ FID_WR_PUT(9)
return 1;
}
/* Part of FI_SWITCH filter iterator */
static void
f_add_tree_lines(const struct f_tree *t, void *fit_)
{
struct filter_iterator * fit = fit_;
if (t->data)
BUFFER_PUSH(fit->lines) = t->data;
}
/* Filter line iterator */
void
f_add_lines(const struct f_line_item *what, struct filter_iterator *fit)
{
switch(what->fi_code) {
FID_WR_PUT(10)
}
}
#if defined(__GNUC__) && __GNUC__ >= 6
#pragma GCC diagnostic pop
#endif

24
filter/f-inst.c
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@ -172,6 +172,22 @@
* m4_dnl use macros f1 and f2.
* m4_dnl For writing directly here, use FID_SAME_BODY.
*
* m4_dnl f_add_lines(...)
* m4_dnl {
* m4_dnl switch (what_->fi_code) {
* m4_dnl case FI_EXAMPLE:
* m4_dnl (109) [[ put it here ]]
* m4_dnl break;
* m4_dnl }
* m4_dnl }
* m4_dnl This code adds new filter lines reachable from the instruction
* m4_dnl to the filter iterator line buffer. This is for instructions
* m4_dnl that changes conrol flow, like FI_CONDITION or FI_CALL, most
* m4_dnl instructions do not need to update it. It is used in generic
* m4_dnl filter iteration code (FILTER_ITERATE*). For accessing your
* m4_dnl custom instruction data, use macros f1 and f2. For writing
* m4_dnl directly here, use FID_ITERATE_BODY.
*
* m4_dnl interpret(...)
* m4_dnl {
* m4_dnl switch (what->fi_code) {
@ -948,6 +964,10 @@
FID_SAME_BODY()
if (!(f1->sym->flags & SYM_FLAG_SAME))
return 0;
FID_ITERATE_BODY()
BUFFER_PUSH(fit->lines) = whati->sym->function;
FID_INTERPRET_BODY()
/* Push the body on stack */
@ -977,6 +997,10 @@
FID_MEMBER(struct f_tree *, tree, [[!same_tree(f1->tree, f2->tree)]], "tree %p", item->tree);
FID_ITERATE_BODY()
tree_walk(whati->tree, f_add_tree_lines, fit);
FID_INTERPRET_BODY()
const struct f_tree *t = find_tree(tree, &v1);
if (!t) {
v1.type = T_VOID;

36
filter/f-inst.h
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@ -17,6 +17,7 @@
#include "conf/conf.h"
#include "filter/filter.h"
#include "filter/data.h"
#include "lib/buffer.h"
#include "lib/flowspec.h"
/* Flags for instructions */
@ -50,6 +51,41 @@ static inline struct f_line *f_linearize(const struct f_inst *root)
void f_dump_line(const struct f_line *, uint indent);
/* Recursive iteration over filter instructions */
struct filter_iterator {
BUFFER_(const struct f_line *) lines;
};
void f_add_lines(const struct f_line_item *what, struct filter_iterator *fit);
#define FILTER_ITERATE_INIT(fit, filter, pool) \
({ \
BUFFER_INIT((fit)->lines, (pool), 32); \
BUFFER_PUSH((fit)->lines) = (filter)->root; \
})
#define FILTER_ITERATE(fit, fi) ({ \
const struct f_line *fl_; \
while (!BUFFER_EMPTY((fit)->lines)) \
{ \
BUFFER_POP((fit)->lines); \
fl_ = (fit)->lines.data[(fit)->lines.used]; \
for (uint i_ = 0; i_ < fl_->len; i_++) \
{ \
const struct f_line_item *fi = &fl_->items[i_]; \
f_add_lines(fi, (fit));
#define FILTER_ITERATE_END } } })
#define FILTER_ITERATE_CLEANUP(fit) \
({ \
mb_free((fit)->lines.data); \
memset((fit), 0, sizeof(struct filter_iterator)); \
})
struct filter *f_new_where(struct f_inst *);
static inline struct f_dynamic_attr f_new_dynamic_attr(u8 type, enum f_type f_type, uint code) /* Type as core knows it, type as filters know it, and code of dynamic attribute */
{ return (struct f_dynamic_attr) { .type = type, .f_type = f_type, .ea_code = code }; } /* f_type currently unused; will be handy for static type checking */

11
filter/tree.c
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@ -170,3 +170,14 @@ tree_format(const struct f_tree *t, buffer *buf)
buffer_puts(buf, "]");
}
void
tree_walk(const struct f_tree *t, void (*hook)(const struct f_tree *, void *), void *data)
{
if (!t)
return;
tree_walk(t->left, hook, data);
hook(t, data);
tree_walk(t->right, hook, data);
}

2
lib/buffer.h
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@ -50,6 +50,8 @@
#define BUFFER_FLUSH(v) ({ (v).used = 0; })
#define BUFFER_EMPTY(v) ({ (v).used == 0; })
#define BUFFER_WALK(v,n) \
for (BUFFER_TYPE(v) *_n = (v).data, n; _n < ((v).data + (v).used) && (n = *_n, 1); _n++)

1
nest/proto.c
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@ -20,6 +20,7 @@
#include "nest/iface.h"
#include "nest/cli.h"
#include "filter/filter.h"
#include "filter/f-inst.h"
pool *proto_pool;
list proto_list;