Implement --echo option

When used with add, insert or replace commands, nft tool will print
event notifications just like 'nft monitor' does for the same commands.

Apart from seeing what a given command will turn out in the rule set,
this allows to reliably retrieve a new rule's assigned handle (if used
together with --handle option).

Here are some examples of how it works:

| # nft --echo --handle add table ip t
| add table ip t
|
| # nft --echo --handle add chain ip t c \
| 	'{ type filter hook forward priority 0; }'
| add chain ip t c { type filter hook forward priority 0; policy accept; }
|
| # nft --echo --handle add rule ip t c tcp dport '{22, 80}' accept
| add rule ip t c tcp dport { ssh, http } accept # handle 2
|
| # nft --echo --handle add set ip t ipset '{ type ipv4_addr; \
| 	elements = { 192.168.0.1, 192.168.0.2 }; }'
| add set ip t ipset { type ipv4_addr; }
| add element ip t ipset { 192.168.0.1 }
| add element ip t ipset { 192.168.0.2 }

Signed-off-by: Phil Sutter <phil@nwl.cc>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 7 insertions, 0 deletions

diff --git a/src/evaluate.c b/src/evaluate.c
index d24526fe..477fb54d 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -2962,6 +2962,9 @@ static int cmd_evaluate_add(struct eval_ctx *ctx, struct cmd *cmd)
 		handle_merge(&cmd->set->handle, &cmd->handle);
 		return set_evaluate(ctx, cmd->set);
 	case CMD_OBJ_RULE:
+		ret = cache_update(ctx->nf_sock, cmd->op, ctx->msgs);
+		if (ret < 0)
+			return ret;
 		handle_merge(&cmd->rule->handle, &cmd->handle);
 		return rule_evaluate(ctx, cmd->rule);
 	case CMD_OBJ_CHAIN:
@@ -2975,6 +2978,10 @@ static int cmd_evaluate_add(struct eval_ctx *ctx, struct cmd *cmd)
 	case CMD_OBJ_COUNTER:
 	case CMD_OBJ_QUOTA:
 	case CMD_OBJ_CT_HELPER:
+		ret = cache_update(ctx->nf_sock, cmd->op, ctx->msgs);
+		if (ret < 0)
+			return ret;
+
 		return 0;
 	default:
 		BUG("invalid command object type %u\n", cmd->obj);