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net: ip: make ip_route_input_noref() return drop reasons

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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: Menglong Dong <dongml2@chinatelecom.cn>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This commit is contained in:
Menglong Dong 2024-11-07 20:55:58 +08:00 committed by Paolo Abeni
parent 61b95c70f3
commit 82d9983ebe
5 changed files with 26 additions and 20 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
include/net/route.h
View File

@ -203,8 +203,9 @@ 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,
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);
int ip_route_use_hint(struct sk_buff *skb, __be32 daddr, __be32 saddr,
dscp_t dscp, struct net_device *dev,
const struct sk_buff *hint);
@ -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,

6
net/core/lwt_bpf.c
View File

@ -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,
ip4h_dscp(iph), dev);
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);

11
net/ipv4/ip_fragment.c
View File

@ -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 @@ out:
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);
}

7
net/ipv4/ip_input.c
View File

@ -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,
ip4h_dscp(iph), dev);
if (unlikely(err))
drop_reason = ip_route_input_noref(skb, iph->daddr, iph->saddr,
ip4h_dscp(iph), dev);
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);

7
net/ipv4/route.c
View File

@ -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);