netfilter: nf_tables: remove skb and nlh from context structure

Instead of caching the original skbuff that contains the netlink
messages, this stores the netlink message sequence number, the
netlink portID and the report flag. This helps to prepare the
introduction of the object release via call_rcu.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 46 insertions, 55 deletions

diff --git a/net/netfilter/nf_tables_api.c b/net/netfilter/nf_tables_api.c
index 86d055a51f0b..4147166ad17c 100644
--- a/net/netfilter/nf_tables_api.c
+++ b/net/netfilter/nf_tables_api.c
@@ -96,13 +96,14 @@ static void nft_ctx_init(struct nft_ctx *ctx,
 			 struct nft_chain *chain,
 			 const struct nlattr * const *nla)
 {
-	ctx->net   = sock_net(skb->sk);
-	ctx->skb   = skb;
-	ctx->nlh   = nlh;
-	ctx->afi   = afi;
-	ctx->table = table;
-	ctx->chain = chain;
-	ctx->nla   = nla;
+	ctx->net	= sock_net(skb->sk);
+	ctx->afi	= afi;
+	ctx->table	= table;
+	ctx->chain	= chain;
+	ctx->nla   	= nla;
+	ctx->portid	= NETLINK_CB(skb).portid;
+	ctx->report	= nlmsg_report(nlh);
+	ctx->seq	= nlh->nlmsg_seq;
 }
 
 static struct nft_trans *nft_trans_alloc(struct nft_ctx *ctx, int msg_type,
@@ -238,14 +239,10 @@ nla_put_failure:
 static int nf_tables_table_notify(const struct nft_ctx *ctx, int event)
 {
 	struct sk_buff *skb;
-	u32 portid = NETLINK_CB(ctx->skb).portid;
-	u32 seq = ctx->nlh->nlmsg_seq;
-	struct net *net = sock_net(ctx->skb->sk);
-	bool report;
 	int err;
 
-	report = nlmsg_report(ctx->nlh);
-	if (!report && !nfnetlink_has_listeners(net, NFNLGRP_NFTABLES))
+	if (!ctx->report &&
+	    !nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES))
 		return 0;
 
 	err = -ENOBUFS;
@@ -253,18 +250,20 @@ static int nf_tables_table_notify(const struct nft_ctx *ctx, int event)
 	if (skb == NULL)
 		goto err;
 
-	err = nf_tables_fill_table_info(skb, portid, seq, event, 0,
+	err = nf_tables_fill_table_info(skb, ctx->portid, ctx->seq, event, 0,
 					ctx->afi->family, ctx->table);
 	if (err < 0) {
 		kfree_skb(skb);
 		goto err;
 	}
 
-	err = nfnetlink_send(skb, net, portid, NFNLGRP_NFTABLES, report,
-			     GFP_KERNEL);
+	err = nfnetlink_send(skb, ctx->net, ctx->portid, NFNLGRP_NFTABLES,
+			     ctx->report, GFP_KERNEL);
 err:
-	if (err < 0)
-		nfnetlink_set_err(net, portid, NFNLGRP_NFTABLES, err);
+	if (err < 0) {
+		nfnetlink_set_err(ctx->net, ctx->portid, NFNLGRP_NFTABLES,
+				  err);
+	}
 	return err;
 }
 
@@ -721,14 +720,10 @@ nla_put_failure:
 static int nf_tables_chain_notify(const struct nft_ctx *ctx, int event)
 {
 	struct sk_buff *skb;
-	u32 portid = NETLINK_CB(ctx->skb).portid;
-	struct net *net = sock_net(ctx->skb->sk);
-	u32 seq = ctx->nlh->nlmsg_seq;
-	bool report;
 	int err;
 
-	report = nlmsg_report(ctx->nlh);
-	if (!report && !nfnetlink_has_listeners(net, NFNLGRP_NFTABLES))
+	if (!ctx->report &&
+	    !nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES))
 		return 0;
 
 	err = -ENOBUFS;
@@ -736,7 +731,7 @@ static int nf_tables_chain_notify(const struct nft_ctx *ctx, int event)
 	if (skb == NULL)
 		goto err;
 
-	err = nf_tables_fill_chain_info(skb, portid, seq, event, 0,
+	err = nf_tables_fill_chain_info(skb, ctx->portid, ctx->seq, event, 0,
 					ctx->afi->family, ctx->table,
 					ctx->chain);
 	if (err < 0) {
@@ -744,11 +739,13 @@ static int nf_tables_chain_notify(const struct nft_ctx *ctx, int event)
 		goto err;
 	}
 
-	err = nfnetlink_send(skb, net, portid, NFNLGRP_NFTABLES, report,
-			     GFP_KERNEL);
+	err = nfnetlink_send(skb, ctx->net, ctx->portid, NFNLGRP_NFTABLES,
+			     ctx->report, GFP_KERNEL);
 err:
-	if (err < 0)
-		nfnetlink_set_err(net, portid, NFNLGRP_NFTABLES, err);
+	if (err < 0) {
+		nfnetlink_set_err(ctx->net, ctx->portid, NFNLGRP_NFTABLES,
+				  err);
+	}
 	return err;
 }
 
@@ -1473,16 +1470,11 @@ static int nf_tables_rule_notify(const struct nft_ctx *ctx,
 				 const struct nft_rule *rule,
 				 int event)
 {
-	const struct sk_buff *oskb = ctx->skb;
 	struct sk_buff *skb;
-	u32 portid = NETLINK_CB(oskb).portid;
-	struct net *net = sock_net(oskb->sk);
-	u32 seq = ctx->nlh->nlmsg_seq;
-	bool report;
 	int err;
 
-	report = nlmsg_report(ctx->nlh);
-	if (!report && !nfnetlink_has_listeners(net, NFNLGRP_NFTABLES))
+	if (!ctx->report &&
+	    !nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES))
 		return 0;
 
 	err = -ENOBUFS;
@@ -1490,7 +1482,7 @@ static int nf_tables_rule_notify(const struct nft_ctx *ctx,
 	if (skb == NULL)
 		goto err;
 
-	err = nf_tables_fill_rule_info(skb, portid, seq, event, 0,
+	err = nf_tables_fill_rule_info(skb, ctx->portid, ctx->seq, event, 0,
 				       ctx->afi->family, ctx->table,
 				       ctx->chain, rule);
 	if (err < 0) {
@@ -1498,11 +1490,13 @@ static int nf_tables_rule_notify(const struct nft_ctx *ctx,
 		goto err;
 	}
 
-	err = nfnetlink_send(skb, net, portid, NFNLGRP_NFTABLES, report,
-			     GFP_KERNEL);
+	err = nfnetlink_send(skb, ctx->net, ctx->portid, NFNLGRP_NFTABLES,
+			     ctx->report, GFP_KERNEL);
 err:
-	if (err < 0)
-		nfnetlink_set_err(net, portid, NFNLGRP_NFTABLES, err);
+	if (err < 0) {
+		nfnetlink_set_err(ctx->net, ctx->portid, NFNLGRP_NFTABLES,
+				  err);
+	}
 	return err;
 }
 
@@ -2141,8 +2135,8 @@ static int nf_tables_fill_set(struct sk_buff *skb, const struct nft_ctx *ctx,
 	struct nfgenmsg *nfmsg;
 	struct nlmsghdr *nlh;
 	struct nlattr *desc;
-	u32 portid = NETLINK_CB(ctx->skb).portid;
-	u32 seq = ctx->nlh->nlmsg_seq;
+	u32 portid = ctx->portid;
+	u32 seq = ctx->seq;
 
 	event |= NFNL_SUBSYS_NFTABLES << 8;
 	nlh = nlmsg_put(skb, portid, seq, event, sizeof(struct nfgenmsg),
@@ -2194,12 +2188,11 @@ static int nf_tables_set_notify(const struct nft_ctx *ctx,
 				int event)
 {
 	struct sk_buff *skb;
-	u32 portid = NETLINK_CB(ctx->skb).portid;
-	bool report;
+	u32 portid = ctx->portid;
 	int err;
 
-	report = nlmsg_report(ctx->nlh);
-	if (!report && !nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES))
+	if (!ctx->report &&
+	    !nfnetlink_has_listeners(ctx->net, NFNLGRP_NFTABLES))
 		return 0;
 
 	err = -ENOBUFS;
@@ -2213,8 +2206,8 @@ static int nf_tables_set_notify(const struct nft_ctx *ctx,
 		goto err;
 	}
 
-	err = nfnetlink_send(skb, ctx->net, portid, NFNLGRP_NFTABLES, report,
-			     GFP_KERNEL);
+	err = nfnetlink_send(skb, ctx->net, portid, NFNLGRP_NFTABLES,
+			     ctx->report, GFP_KERNEL);
 err:
 	if (err < 0)
 		nfnetlink_set_err(ctx->net, portid, NFNLGRP_NFTABLES, err);
@@ -2956,14 +2949,12 @@ static int nf_tables_setelem_notify(const struct nft_ctx *ctx,
 				    const struct nft_set_elem *elem,
 				    int event, u16 flags)
 {
-	const struct sk_buff *oskb = ctx->skb;
-	struct net *net = sock_net(oskb->sk);
-	u32 portid = NETLINK_CB(oskb).portid;
-	bool report = nlmsg_report(ctx->nlh);
+	struct net *net = ctx->net;
+	u32 portid = ctx->portid;
 	struct sk_buff *skb;
 	int err;
 
-	if (!report && !nfnetlink_has_listeners(net, NFNLGRP_NFTABLES))
+	if (!ctx->report && !nfnetlink_has_listeners(net, NFNLGRP_NFTABLES))
 		return 0;
 
 	err = -ENOBUFS;
@@ -2978,7 +2969,7 @@ static int nf_tables_setelem_notify(const struct nft_ctx *ctx,
 		goto err;
 	}
 
-	err = nfnetlink_send(skb, net, portid, NFNLGRP_NFTABLES, report,
+	err = nfnetlink_send(skb, net, portid, NFNLGRP_NFTABLES, ctx->report,
 			     GFP_KERNEL);
 err:
 	if (err < 0)