[PATCH nft WIP] jump: Allow jump to a variable when using nft input files

[Fernando Fernandez Mancera]

This patch introduces the use of nft input files variables in 'jump'
statements, e.g.

define dest = chainame

add rule ip filter input jump $dest

Signed-off-by: Fernando Fernandez Mancera <ffmanc...@riseup.net>
---
 include/expression.h |  3 ++-
 src/expression.c     | 14 ++++++++++++--
 src/netlink.c        |  6 +++---
 src/parser_bison.y   | 16 ++++++++++------
 4 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/include/expression.h b/include/expression.h
index 6416ac0..0379eba 100644
--- a/include/expression.h
+++ b/include/expression.h
@@ -403,7 +403,8 @@ extern void relational_expr_pctx_update(struct proto_ctx 
*ctx,
                                        const struct expr *expr);
 
 extern struct expr *verdict_expr_alloc(const struct location *loc,
-                                      int verdict, const char *chain);
+                                      int verdict, const char *chain,
+                                      struct expr *variable);
 
 extern struct expr *symbol_expr_alloc(const struct location *loc,
                                      enum symbol_types type, struct scope 
*scope,
diff --git a/src/expression.c b/src/expression.c
index eece12e..7956a9c 100644
--- a/src/expression.c
+++ b/src/expression.c
@@ -236,15 +236,25 @@ static const struct expr_ops verdict_expr_ops = {
 };
 
 struct expr *verdict_expr_alloc(const struct location *loc,
-                               int verdict, const char *chain)
+                               int verdict, const char *chain,
+                               struct expr *variable)
 {
+       struct symbol *sym;
        struct expr *expr;
+       char *sym_chain;
 
        expr = expr_alloc(loc, EXPR_VERDICT, &verdict_type,
                          BYTEORDER_INVALID, 0);
        expr->verdict = verdict;
-       if (chain != NULL)
+       if (chain != NULL) {
                expr->chain = chain;
+       } else if (variable != NULL) {
+               sym = variable->sym;
+               if (sym->expr->value)
+                       expr->chain = mpz_get_str(NULL, 10, sym->expr->value);
+               //printf("%s", expr->chain);
+       }
+       printf("%s", expr->chain);
        expr->flags = EXPR_F_CONSTANT | EXPR_F_SINGLETON;
        return expr;
 }
diff --git a/src/netlink.c b/src/netlink.c
index c051ae6..ce1a8c4 100644
--- a/src/netlink.c
+++ b/src/netlink.c
@@ -265,7 +265,7 @@ static struct expr *netlink_alloc_verdict(const struct 
location *loc,
                break;
        }
 
-       return verdict_expr_alloc(loc, nld->verdict, chain);
+       return verdict_expr_alloc(loc, nld->verdict, chain, NULL);
 }
 
 struct expr *netlink_alloc_data(const struct location *loc,
@@ -1160,7 +1160,7 @@ static void trace_print_verdict(const struct nftnl_trace 
*nlt,
        verdict = nftnl_trace_get_u32(nlt, NFTNL_TRACE_VERDICT);
        if (nftnl_trace_is_set(nlt, NFTNL_TRACE_JUMP_TARGET))
                chain = xstrdup(nftnl_trace_get_str(nlt, 
NFTNL_TRACE_JUMP_TARGET));
-       expr = verdict_expr_alloc(&netlink_location, verdict, chain);
+       expr = verdict_expr_alloc(&netlink_location, verdict, chain, NULL);
 
        nft_print(octx, "verdict ");
        expr_print(expr, octx);
@@ -1175,7 +1175,7 @@ static void trace_print_policy(const struct nftnl_trace 
*nlt,
 
        policy = nftnl_trace_get_u32(nlt, NFTNL_TRACE_POLICY);
 
-       expr = verdict_expr_alloc(&netlink_location, policy, NULL);
+       expr = verdict_expr_alloc(&netlink_location, policy, NULL, NULL);
 
        nft_print(octx, "policy ");
        expr_print(expr, octx);
diff --git a/src/parser_bison.y b/src/parser_bison.y
index 9aea652..7f131ad 100644
--- a/src/parser_bison.y
+++ b/src/parser_bison.y
@@ -3817,27 +3817,31 @@ relational_op           :       EQ              { $$ = 
OP_EQ; }
 
 verdict_expr           :       ACCEPT
                        {
-                               $$ = verdict_expr_alloc(&@$, NF_ACCEPT, NULL);
+                               $$ = verdict_expr_alloc(&@$, NF_ACCEPT, NULL, 
NULL);
                        }
                        |       DROP
                        {
-                               $$ = verdict_expr_alloc(&@$, NF_DROP, NULL);
+                               $$ = verdict_expr_alloc(&@$, NF_DROP, NULL, 
NULL);
                        }
                        |       CONTINUE
                        {
-                               $$ = verdict_expr_alloc(&@$, NFT_CONTINUE, 
NULL);
+                               $$ = verdict_expr_alloc(&@$, NFT_CONTINUE, 
NULL, NULL);
+                       }
+                       |       JUMP                    variable_expr
+                       {
+                               $$ = verdict_expr_alloc(&@$, NFT_JUMP, NULL, 
$2);
                        }
                        |       JUMP                    identifier
                        {
-                               $$ = verdict_expr_alloc(&@$, NFT_JUMP, $2);
+                               $$ = verdict_expr_alloc(&@$, NFT_JUMP, $2, 
NULL);
                        }
                        |       GOTO                    identifier
                        {
-                               $$ = verdict_expr_alloc(&@$, NFT_GOTO, $2);
+                               $$ = verdict_expr_alloc(&@$, NFT_GOTO, $2, 
NULL);
                        }
                        |       RETURN
                        {
-                               $$ = verdict_expr_alloc(&@$, NFT_RETURN, NULL);
+                               $$ = verdict_expr_alloc(&@$, NFT_RETURN, NULL, 
NULL);
                        }
                        ;
 
-- 
2.20.1