netfilter: nft_compat: add ebtables support

This patch extends nft_compat to support ebtables extensions.

ebtables verdict codes are translated to the ones used by the nf_tables engine,
so we can properly use ebtables target extensions from nft_compat.

This patch extends previous work by Giuseppe Longo <giuseppelng@gmail.com>.

Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 57 insertions, 6 deletions

diff --git a/net/netfilter/nft_compat.c b/net/netfilter/nft_compat.c
index 265e190f2218..c598f74063a1 100644
--- a/net/netfilter/nft_compat.c
+++ b/net/netfilter/nft_compat.c
@@ -19,6 +19,7 @@
 #include <linux/netfilter/x_tables.h>
 #include <linux/netfilter_ipv4/ip_tables.h>
 #include <linux/netfilter_ipv6/ip6_tables.h>
+#include <linux/netfilter_bridge/ebtables.h>
 #include <net/netfilter/nf_tables.h>
 
 static int nft_compat_chain_validate_dependency(const char *tablename,
@@ -40,6 +41,7 @@ static int nft_compat_chain_validate_dependency(const char *tablename,
 union nft_entry {
         struct ipt_entry e4;
         struct ip6t_entry e6;
+        struct ebt_entry ebt;
 };
 
 static inline void
@@ -50,9 +52,9 @@ nft_compat_set_par(struct xt_action_param *par, void *xt, const void *xt_info)
         par->hotdrop    = false;
 }
 
-static void nft_target_eval(const struct nft_expr *expr,
-                            struct nft_data data[NFT_REG_MAX + 1],
-                            const struct nft_pktinfo *pkt)
+static void nft_target_eval_xt(const struct nft_expr *expr,
+                               struct nft_data data[NFT_REG_MAX + 1],
+                               const struct nft_pktinfo *pkt)
 {
         void *info = nft_expr_priv(expr);
         struct xt_target *target = expr->ops->data;
@@ -66,7 +68,7 @@ static void nft_target_eval(const struct nft_expr *expr,
         if (pkt->xt.hotdrop)
                 ret = NF_DROP;
 
-        switch(ret) {
+        switch (ret) {
         case XT_CONTINUE:
                 data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
                 break;
@@ -74,7 +76,41 @@ static void nft_target_eval(const struct nft_expr *expr,
                 data[NFT_REG_VERDICT].verdict = ret;
                 break;
         }
-        return;
+}
+
+static void nft_target_eval_bridge(const struct nft_expr *expr,
+                                   struct nft_data data[NFT_REG_MAX + 1],
+                                   const struct nft_pktinfo *pkt)
+{
+        void *info = nft_expr_priv(expr);
+        struct xt_target *target = expr->ops->data;
+        struct sk_buff *skb = pkt->skb;
+        int ret;
+
+        nft_compat_set_par((struct xt_action_param *)&pkt->xt, target, info);
+
+        ret = target->target(skb, &pkt->xt);
+
+        if (pkt->xt.hotdrop)
+                ret = NF_DROP;
+
+        switch (ret) {
+        case EBT_ACCEPT:
+                data[NFT_REG_VERDICT].verdict = NF_ACCEPT;
+                break;
+        case EBT_DROP:
+                data[NFT_REG_VERDICT].verdict = NF_DROP;
+                break;
+        case EBT_CONTINUE:
+                data[NFT_REG_VERDICT].verdict = NFT_CONTINUE;
+                break;
+        case EBT_RETURN:
+                data[NFT_REG_VERDICT].verdict = NFT_RETURN;
+                break;
+        default:
+                data[NFT_REG_VERDICT].verdict = ret;
+                break;
+        }
 }
 
 static const struct nla_policy nft_target_policy[NFTA_TARGET_MAX + 1] = {
@@ -100,6 +136,10 @@ nft_target_set_tgchk_param(struct xt_tgchk_param *par,
                 entry->e6.ipv6.proto = proto;
                 entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
                 break;
+        case NFPROTO_BRIDGE:
+                entry->ebt.ethproto = proto;
+                entry->ebt.invflags = inv ? EBT_IPROTO : 0;
+                break;
         }
         par->entryinfo  = entry;
         par->target     = target;
@@ -307,6 +347,10 @@ nft_match_set_mtchk_param(struct xt_mtchk_param *par, const struct nft_ctx *ctx,
                 entry->e6.ipv6.proto = proto;
                 entry->e6.ipv6.invflags = inv ? IP6T_INV_PROTO : 0;
                 break;
+        case NFPROTO_BRIDGE:
+                entry->ebt.ethproto = proto;
+                entry->ebt.invflags = inv ? EBT_IPROTO : 0;
+                break;
         }
         par->entryinfo  = entry;
         par->match      = match;
@@ -490,6 +534,9 @@ nfnl_compat_get(struct sock *nfnl, struct sk_buff *skb,
         case AF_INET6:
                 fmt = "ip6t_%s";
                 break;
+        case NFPROTO_BRIDGE:
+                fmt = "ebt_%s";
+                break;
         default:
                 pr_err("nft_compat: unsupported protocol %d\n",
                         nfmsg->nfgen_family);
@@ -663,13 +710,17 @@ nft_target_select_ops(const struct nft_ctx *ctx,
 
         nft_target->ops.type = &nft_target_type;
         nft_target->ops.size = NFT_EXPR_SIZE(XT_ALIGN(target->targetsize));
-        nft_target->ops.eval = nft_target_eval;
         nft_target->ops.init = nft_target_init;
         nft_target->ops.destroy = nft_target_destroy;
         nft_target->ops.dump = nft_target_dump;
         nft_target->ops.validate = nft_target_validate;
         nft_target->ops.data = target;
 
+        if (family == NFPROTO_BRIDGE)
+                nft_target->ops.eval = nft_target_eval_bridge;
+        else
+                nft_target->ops.eval = nft_target_eval_xt;
+
         list_add(&nft_target->head, &nft_target_list);
 
         return &nft_target->ops;