From 4a75ed32132d8e2292dd276f3ea7f4edec4f3d06 Mon Sep 17 00:00:00 2001 From: Florian Westphal Date: Thu, 15 Sep 2016 17:28:00 +0200 Subject: src: add fib expression This adds the 'fib' expression which can be used to obtain the output interface from the route table based on either source or destination address of a packet. This can be used to e.g. add reverse path filtering: # drop if not coming from the same interface packet # arrived on # nft add rule x prerouting fib saddr . iif oif eq 0 drop # accept only if from eth0 # nft add rule x prerouting fib saddr . iif oif eq "eth0" accept # accept if from any valid interface # nft add rule x prerouting fib saddr oif accept Querying of address type is also supported. This can be used to e.g. only accept packets to addresses configured in the same interface: # fib daddr . iif type local Its also possible to use mark and verdict map, e.g.: # nft add rule x prerouting meta mark set 0xdead fib daddr . mark type vmap { blackhole : drop, prohibit : drop, unicast : accept } Signed-off-by: Florian Westphal --- src/netlink_linearize.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'src/netlink_linearize.c') diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c index a5d4502f..b5967d49 100644 --- a/src/netlink_linearize.c +++ b/src/netlink_linearize.c @@ -104,6 +104,20 @@ static void netlink_gen_concat(struct netlink_linearize_ctx *ctx, } } +static void netlink_gen_fib(struct netlink_linearize_ctx *ctx, + const struct expr *expr, + enum nft_registers dreg) +{ + struct nftnl_expr *nle; + + nle = alloc_nft_expr("fib"); + netlink_put_register(nle, NFTNL_EXPR_FIB_DREG, dreg); + nftnl_expr_set_u32(nle, NFTNL_EXPR_FIB_RESULT, expr->fib.result); + nftnl_expr_set_u32(nle, NFTNL_EXPR_FIB_FLAGS, expr->fib.flags); + + nftnl_rule_add_expr(ctx->nlr, nle); +} + static void netlink_gen_hash(struct netlink_linearize_ctx *ctx, const struct expr *expr, enum nft_registers dreg) @@ -663,6 +677,8 @@ static void netlink_gen_expr(struct netlink_linearize_ctx *ctx, return netlink_gen_numgen(ctx, expr, dreg); case EXPR_HASH: return netlink_gen_hash(ctx, expr, dreg); + case EXPR_FIB: + return netlink_gen_fib(ctx, expr, dreg); default: BUG("unknown expression type %s\n", expr->ops->name); } -- cgit v1.2.3