Commit 82d9983e authored by Menglong Dong's avatar Menglong Dong Committed by Paolo Abeni
Browse files

net: ip: make ip_route_input_noref() return drop reasons 



In this commit, we make ip_route_input_noref() return drop reasons, which
come from ip_route_input_rcu().

We need adjust the callers of ip_route_input_noref() to make sure the
return value of ip_route_input_noref() is used properly.

The errno that ip_route_input_noref() returns comes from ip_route_input
and bpf_lwt_input_reroute in the origin logic, and we make them return
-EINVAL on error instead. In the following patch, we will make
ip_route_input() returns drop reasons too.

Signed-off-by: default avatarMenglong Dong <dongml2@chinatelecom.cn>
Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
parent 61b95c70

include/net/route.h

+8 −7
Original line number Diff line number Diff line
@@ -203,7 +203,8 @@ enum skb_drop_reason 
ip_mc_validate_source(struct sk_buff *skb, __be32 daddr, __be32 saddr,

		      dscp_t dscp, struct net_device *dev,

		      struct in_device *in_dev, u32 *itag);

int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,

enum skb_drop_reason

ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,

		     dscp_t dscp, struct net_device *dev);

int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,

		      dscp_t dscp, struct net_device *dev,
@@ -212,18 +213,18 @@ int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr, 
static inline int ip_route_input(struct sk_buff *skb, __be32 dst, __be32 src,

				 dscp_t dscp, struct net_device *devin)

{

	int err;

	enum skb_drop_reason reason;



	rcu_read_lock();

	err = ip_route_input_noref(skb, dst, src, dscp, devin);

	if (!err) {

	reason = ip_route_input_noref(skb, dst, src, dscp, devin);

	if (!reason) {

		skb_dst_force(skb);

		if (!skb_dst(skb))

			err = -EINVAL;

			reason = SKB_DROP_REASON_NOT_SPECIFIED;

	}

	rcu_read_unlock();



	return err;

	return reason ? -EINVAL : 0;

}



void ipv4_update_pmtu(struct sk_buff *skb, struct net *net, u32 mtu, int oif,

net/core/lwt_bpf.c

+4 −2
Original line number Diff line number Diff line
@@ -88,6 +88,7 @@ static int run_lwt_bpf(struct sk_buff *skb, struct bpf_lwt_prog *lwt, 


static int bpf_lwt_input_reroute(struct sk_buff *skb)

{

	enum skb_drop_reason reason;

	int err = -EINVAL;



	if (skb->protocol == htons(ETH_P_IP)) {
@@ -96,8 +97,9 @@ static int bpf_lwt_input_reroute(struct sk_buff *skb) 


		dev_hold(dev);

		skb_dst_drop(skb);

		err = ip_route_input_noref(skb, iph->daddr, iph->saddr,

		reason = ip_route_input_noref(skb, iph->daddr, iph->saddr,

					      ip4h_dscp(iph), dev);

		err = reason ? -EINVAL : 0;

		dev_put(dev);

	} else if (skb->protocol == htons(ETH_P_IPV6)) {

		skb_dst_drop(skb);

net/ipv4/ip_fragment.c

+6 −5
Original line number Diff line number Diff line
@@ -132,12 +132,12 @@ static bool frag_expire_skip_icmp(u32 user) 
 */

static void ip_expire(struct timer_list *t)

{

	enum skb_drop_reason reason = SKB_DROP_REASON_FRAG_REASM_TIMEOUT;

	struct inet_frag_queue *frag = from_timer(frag, t, timer);

	const struct iphdr *iph;

	struct sk_buff *head = NULL;

	struct net *net;

	struct ipq *qp;

	int err;



	qp = container_of(frag, struct ipq, q);

	net = qp->q.fqdir->net;
@@ -175,14 +175,15 @@ static void ip_expire(struct timer_list *t) 


	/* skb has no dst, perform route lookup again */

	iph = ip_hdr(head);

	err = ip_route_input_noref(head, iph->daddr, iph->saddr, ip4h_dscp(iph),

				   head->dev);

	if (err)

	reason = ip_route_input_noref(head, iph->daddr, iph->saddr,

				      ip4h_dscp(iph), head->dev);

	if (reason)

		goto out;



	/* Only an end host needs to send an ICMP

	 * "Fragment Reassembly Timeout" message, per RFC792.

	 */

	reason = SKB_DROP_REASON_FRAG_REASM_TIMEOUT;

	if (frag_expire_skip_icmp(qp->q.key.v4.user) &&

	    (skb_rtable(head)->rt_type != RTN_LOCAL))

		goto out;
@@ -195,7 +196,7 @@ static void ip_expire(struct timer_list *t) 
	spin_unlock(&qp->q.lock);

out_rcu_unlock:

	rcu_read_unlock();

	kfree_skb_reason(head, SKB_DROP_REASON_FRAG_REASM_TIMEOUT);

	kfree_skb_reason(head, reason);

	ipq_put(qp);

}

net/ipv4/ip_input.c

+4 −3
Original line number Diff line number Diff line
@@ -362,10 +362,11 @@ static int ip_rcv_finish_core(struct net *net, struct sock *sk, 
	 *	how the packet travels inside Linux networking.

	 */

	if (!skb_valid_dst(skb)) {

		err = ip_route_input_noref(skb, iph->daddr, iph->saddr,

		drop_reason = ip_route_input_noref(skb, iph->daddr, iph->saddr,

						   ip4h_dscp(iph), dev);

		if (unlikely(err))

		if (unlikely(drop_reason))

			goto drop_error;

		drop_reason = SKB_DROP_REASON_NOT_SPECIFIED;

	} else {

		struct in_device *in_dev = __in_dev_get_rcu(dev);

net/ipv4/route.c

+4 −3
Original line number Diff line number Diff line
@@ -2500,8 +2500,9 @@ ip_route_input_rcu(struct sk_buff *skb, __be32 daddr, __be32 saddr, 
	return ip_route_input_slow(skb, daddr, saddr, dscp, dev, res);

}



int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr,

			 dscp_t dscp, struct net_device *dev)

enum skb_drop_reason ip_route_input_noref(struct sk_buff *skb, __be32 daddr,

					  __be32 saddr, dscp_t dscp,

					  struct net_device *dev)

{

	enum skb_drop_reason reason;

	struct fib_result res;
@@ -2510,7 +2511,7 @@ int ip_route_input_noref(struct sk_buff *skb, __be32 daddr, __be32 saddr, 
	reason = ip_route_input_rcu(skb, daddr, saddr, dscp, dev, &res);

	rcu_read_unlock();



	return reason ? -EINVAL : 0;

	return reason;

}

EXPORT_SYMBOL(ip_route_input_noref);