From e5fd91f1ef340da553f7a79da9540c3db711c937 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9=20Fabian=20Silva=20Delgado?=
 <emulatorman@parabola.nu>
Date: Tue, 8 Sep 2015 01:01:14 -0300
Subject: Linux-libre 4.2-gnu

---
 net/sched/act_bpf.c | 59 ++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 43 insertions(+), 16 deletions(-)

(limited to 'net/sched/act_bpf.c')

diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c
index dc6a2d324..d0edeb7a1 100644
--- a/net/sched/act_bpf.c
+++ b/net/sched/act_bpf.c
@@ -27,9 +27,10 @@
 struct tcf_bpf_cfg {
 	struct bpf_prog *filter;
 	struct sock_filter *bpf_ops;
-	char *bpf_name;
+	const char *bpf_name;
 	u32 bpf_fd;
 	u16 bpf_num_ops;
+	bool is_ebpf;
 };
 
 static int tcf_bpf(struct sk_buff *skb, const struct tc_action *act,
@@ -37,6 +38,7 @@ static int tcf_bpf(struct sk_buff *skb, const struct tc_action *act,
 {
 	struct tcf_bpf *prog = act->priv;
 	int action, filter_res;
+	bool at_ingress = G_TC_AT(skb->tc_verd) & AT_INGRESS;
 
 	if (unlikely(!skb_mac_header_was_set(skb)))
 		return TC_ACT_UNSPEC;
@@ -48,7 +50,13 @@ static int tcf_bpf(struct sk_buff *skb, const struct tc_action *act,
 
 	/* Needed here for accessing maps. */
 	rcu_read_lock();
-	filter_res = BPF_PROG_RUN(prog->filter, skb);
+	if (at_ingress) {
+		__skb_push(skb, skb->mac_len);
+		filter_res = BPF_PROG_RUN(prog->filter, skb);
+		__skb_pull(skb, skb->mac_len);
+	} else {
+		filter_res = BPF_PROG_RUN(prog->filter, skb);
+	}
 	rcu_read_unlock();
 
 	/* A BPF program may overwrite the default action opcode.
@@ -200,6 +208,7 @@ static int tcf_bpf_init_from_ops(struct nlattr **tb, struct tcf_bpf_cfg *cfg)
 	cfg->bpf_ops = bpf_ops;
 	cfg->bpf_num_ops = bpf_num_ops;
 	cfg->filter = fp;
+	cfg->is_ebpf = false;
 
 	return 0;
 }
@@ -234,18 +243,40 @@ static int tcf_bpf_init_from_efd(struct nlattr **tb, struct tcf_bpf_cfg *cfg)
 	cfg->bpf_fd = bpf_fd;
 	cfg->bpf_name = name;
 	cfg->filter = fp;
+	cfg->is_ebpf = true;
 
 	return 0;
 }
 
+static void tcf_bpf_cfg_cleanup(const struct tcf_bpf_cfg *cfg)
+{
+	if (cfg->is_ebpf)
+		bpf_prog_put(cfg->filter);
+	else
+		bpf_prog_destroy(cfg->filter);
+
+	kfree(cfg->bpf_ops);
+	kfree(cfg->bpf_name);
+}
+
+static void tcf_bpf_prog_fill_cfg(const struct tcf_bpf *prog,
+				  struct tcf_bpf_cfg *cfg)
+{
+	cfg->is_ebpf = tcf_bpf_is_ebpf(prog);
+	cfg->filter = prog->filter;
+
+	cfg->bpf_ops = prog->bpf_ops;
+	cfg->bpf_name = prog->bpf_name;
+}
+
 static int tcf_bpf_init(struct net *net, struct nlattr *nla,
 			struct nlattr *est, struct tc_action *act,
 			int replace, int bind)
 {
 	struct nlattr *tb[TCA_ACT_BPF_MAX + 1];
+	struct tcf_bpf_cfg cfg, old;
 	struct tc_act_bpf *parm;
 	struct tcf_bpf *prog;
-	struct tcf_bpf_cfg cfg;
 	bool is_bpf, is_ebpf;
 	int ret;
 
@@ -294,6 +325,9 @@ static int tcf_bpf_init(struct net *net, struct nlattr *nla,
 	prog = to_bpf(act);
 	spin_lock_bh(&prog->tcf_lock);
 
+	if (ret != ACT_P_CREATED)
+		tcf_bpf_prog_fill_cfg(prog, &old);
+
 	prog->bpf_ops = cfg.bpf_ops;
 	prog->bpf_name = cfg.bpf_name;
 
@@ -309,29 +343,22 @@ static int tcf_bpf_init(struct net *net, struct nlattr *nla,
 
 	if (ret == ACT_P_CREATED)
 		tcf_hash_insert(act);
+	else
+		tcf_bpf_cfg_cleanup(&old);
 
 	return ret;
 
 destroy_fp:
-	if (is_ebpf)
-		bpf_prog_put(cfg.filter);
-	else
-		bpf_prog_destroy(cfg.filter);
-
-	kfree(cfg.bpf_ops);
-	kfree(cfg.bpf_name);
-
+	tcf_bpf_cfg_cleanup(&cfg);
 	return ret;
 }
 
 static void tcf_bpf_cleanup(struct tc_action *act, int bind)
 {
-	const struct tcf_bpf *prog = act->priv;
+	struct tcf_bpf_cfg tmp;
 
-	if (tcf_bpf_is_ebpf(prog))
-		bpf_prog_put(prog->filter);
-	else
-		bpf_prog_destroy(prog->filter);
+	tcf_bpf_prog_fill_cfg(act->priv, &tmp);
+	tcf_bpf_cfg_cleanup(&tmp);
 }
 
 static struct tc_action_ops act_bpf_ops __read_mostly = {
-- 
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