diff mbox series

[Openvpn-devel,net-next,v3,2/3] net: tunnel: implement noref flows in udp_tunnel{, 6}_xmit_skb

Message ID 20250922110622.10368-3-mmietus97@yahoo.com
State New
Headers show
Series net: tunnel: introduce noref xmit flows for tunnels | expand

Commit Message

Marek Mietus Sept. 22, 2025, 11:06 a.m. UTC 
In cases where udp_tunnel{,6}_xmit_skb is called inside a
RCU read-side critical section, we can avoid referencing
the dst_entry.

Implement noref variants for udp_tunnel{,6}_xmit_skb and
iptunnel_xmit to be used in noref flows.

Signed-off-by: Marek Mietus <mmietus97@yahoo.com>
---
 include/net/ip_tunnels.h   |  3 +++
 include/net/udp_tunnel.h   | 13 ++++++++++
 net/ipv4/ip_tunnel_core.c  | 34 +++++++++++++++++++------
 net/ipv4/udp_tunnel_core.c | 29 +++++++++++++++++++---
 net/ipv6/ip6_udp_tunnel.c  | 51 ++++++++++++++++++++++++++++++--------
 5 files changed, 109 insertions(+), 21 deletions(-)
diff mbox series

Patch

diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 8cf1380f3656..6dcea237bf21 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -604,6 +604,9 @@  static inline int iptunnel_pull_header(struct sk_buff *skb, int hdr_len,
 void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
 		   __be32 src, __be32 dst, u8 proto,
 		   u8 tos, u8 ttl, __be16 df, bool xnet, u16 ipcb_flags);
+void iptunnel_xmit_noref(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
+			 __be32 src, __be32 dst, u8 proto,
+			 u8 tos, u8 ttl, __be16 df, bool xnet, u16 ipcb_flags);
 struct metadata_dst *iptunnel_metadata_reply(struct metadata_dst *md,
 					     gfp_t flags);
 int skb_tunnel_check_pmtu(struct sk_buff *skb, struct dst_entry *encap_dst,
diff --git a/include/net/udp_tunnel.h b/include/net/udp_tunnel.h
index 9acef2fbd2fd..b35e0267e318 100644
--- a/include/net/udp_tunnel.h
+++ b/include/net/udp_tunnel.h
@@ -135,6 +135,10 @@  void udp_tunnel_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *skb
 			 __be32 src, __be32 dst, __u8 tos, __u8 ttl,
 			 __be16 df, __be16 src_port, __be16 dst_port,
 			 bool xnet, bool nocheck, u16 ipcb_flags);
+void udp_tunnel_xmit_skb_noref(struct rtable *rt, struct sock *sk, struct sk_buff *skb,
+			       __be32 src, __be32 dst, __u8 tos, __u8 ttl,
+			       __be16 df, __be16 src_port, __be16 dst_port,
+			       bool xnet, bool nocheck, u16 ipcb_flags);
 
 void udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sock *sk,
 			  struct sk_buff *skb,
@@ -145,6 +149,15 @@  void udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sock *sk,
 			  __be16 src_port, __be16 dst_port, bool nocheck,
 			  u16 ip6cb_flags);
 
+void udp_tunnel6_xmit_skb_noref(struct dst_entry *dst,
+				struct sock *sk, struct sk_buff *skb,
+				struct net_device *dev,
+				const struct in6_addr *saddr,
+				const struct in6_addr *daddr,
+				__u8 prio, __u8 ttl, __be32 label,
+				__be16 src_port, __be16 dst_port,
+				bool nocheck, u16 ip6cb_flags);
+
 void udp_tunnel_sock_release(struct socket *sock);
 
 struct rtable *udp_tunnel_dst_lookup(struct sk_buff *skb,
diff --git a/net/ipv4/ip_tunnel_core.c b/net/ipv4/ip_tunnel_core.c
index cc9915543637..8b03fb380397 100644
--- a/net/ipv4/ip_tunnel_core.c
+++ b/net/ipv4/ip_tunnel_core.c
@@ -47,10 +47,10 @@  const struct ip6_tnl_encap_ops __rcu *
 		ip6tun_encaps[MAX_IPTUN_ENCAP_OPS] __read_mostly;
 EXPORT_SYMBOL(ip6tun_encaps);
 
-void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
-		   __be32 src, __be32 dst, __u8 proto,
-		   __u8 tos, __u8 ttl, __be16 df, bool xnet,
-		   u16 ipcb_flags)
+static void __iptunnel_xmit(struct sock *sk, struct rtable *rt,
+			    struct sk_buff *skb, __be32 src, __be32 dst,
+			    __u8 proto, __u8 tos, __u8 ttl, __be16 df,
+			    u16 ipcb_flags)
 {
 	int pkt_len = skb->len - skb_inner_network_offset(skb);
 	struct net *net = dev_net(rt->dst.dev);
@@ -58,10 +58,7 @@  void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
 	struct iphdr *iph;
 	int err;
 
-	skb_scrub_packet(skb, xnet);
-
 	skb_clear_hash_if_not_l4(skb);
-	skb_dst_set(skb, &rt->dst);
 	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
 	IPCB(skb)->flags = ipcb_flags;
 
@@ -89,8 +86,31 @@  void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
 		iptunnel_xmit_stats(dev, pkt_len);
 	}
 }
+
+void iptunnel_xmit(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
+		   __be32 src, __be32 dst, __u8 proto,
+		   __u8 tos, __u8 ttl, __be16 df, bool xnet,
+		   u16 ipcb_flags)
+{
+	skb_scrub_packet(skb, xnet);
+	skb_dst_set(skb, &rt->dst);
+
+	__iptunnel_xmit(sk, rt, skb, src, dst, proto, tos, ttl, df, ipcb_flags);
+}
 EXPORT_SYMBOL_GPL(iptunnel_xmit);
 
+void iptunnel_xmit_noref(struct sock *sk, struct rtable *rt, struct sk_buff *skb,
+			 __be32 src, __be32 dst, __u8 proto,
+			 __u8 tos, __u8 ttl, __be16 df, bool xnet,
+			 u16 ipcb_flags)
+{
+	skb_scrub_packet(skb, xnet);
+	skb_dst_set_noref(skb, &rt->dst);
+
+	__iptunnel_xmit(sk, rt, skb, src, dst, proto, tos, ttl, df, ipcb_flags);
+}
+EXPORT_SYMBOL_GPL(iptunnel_xmit_noref);
+
 int __iptunnel_pull_header(struct sk_buff *skb, int hdr_len,
 			   __be16 inner_proto, bool raw_proto, bool xnet)
 {
diff --git a/net/ipv4/udp_tunnel_core.c b/net/ipv4/udp_tunnel_core.c
index fce945f23069..c0e9007cf081 100644
--- a/net/ipv4/udp_tunnel_core.c
+++ b/net/ipv4/udp_tunnel_core.c
@@ -170,10 +170,9 @@  void udp_tunnel_notify_del_rx_port(struct socket *sock, unsigned short type)
 }
 EXPORT_SYMBOL_GPL(udp_tunnel_notify_del_rx_port);
 
-void udp_tunnel_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *skb,
-			 __be32 src, __be32 dst, __u8 tos, __u8 ttl,
-			 __be16 df, __be16 src_port, __be16 dst_port,
-			 bool xnet, bool nocheck, u16 ipcb_flags)
+static void udp_tunnel_add_hdr(struct sk_buff *skb, __be32 src,
+			       __be32 dst, __be16 src_port,
+			       __be16 dst_port, bool nocheck)
 {
 	struct udphdr *uh;
 
@@ -188,12 +187,34 @@  void udp_tunnel_xmit_skb(struct rtable *rt, struct sock *sk, struct sk_buff *skb
 	memset(&(IPCB(skb)->opt), 0, sizeof(IPCB(skb)->opt));
 
 	udp_set_csum(nocheck, skb, src, dst, skb->len);
+}
+
+void udp_tunnel_xmit_skb(struct rtable *rt, struct sock *sk,
+			 struct sk_buff *skb, __be32 src, __be32 dst,
+			 __u8 tos, __u8 ttl, __be16 df, __be16 src_port,
+			 __be16 dst_port, bool xnet, bool nocheck,
+			 u16 ipcb_flags)
+{
+	udp_tunnel_add_hdr(skb, src, dst, src_port, dst_port, nocheck);
 
 	iptunnel_xmit(sk, rt, skb, src, dst, IPPROTO_UDP, tos, ttl, df, xnet,
 		      ipcb_flags);
 }
 EXPORT_SYMBOL_GPL(udp_tunnel_xmit_skb);
 
+void udp_tunnel_xmit_skb_noref(struct rtable *rt, struct sock *sk,
+			       struct sk_buff *skb, __be32 src, __be32 dst,
+			       __u8 tos, __u8 ttl, __be16 df, __be16 src_port,
+			       __be16 dst_port, bool xnet, bool nocheck,
+			       u16 ipcb_flags)
+{
+	udp_tunnel_add_hdr(skb, src, dst, src_port, dst_port, nocheck);
+
+	iptunnel_xmit_noref(sk, rt, skb, src, dst, IPPROTO_UDP, tos, ttl, df,
+			    xnet, ipcb_flags);
+}
+EXPORT_SYMBOL_GPL(udp_tunnel_xmit_skb_noref);
+
 void udp_tunnel_sock_release(struct socket *sock)
 {
 	rcu_assign_sk_user_data(sock->sk, NULL);
diff --git a/net/ipv6/ip6_udp_tunnel.c b/net/ipv6/ip6_udp_tunnel.c
index 0ff547a4bff7..d262d0a0a178 100644
--- a/net/ipv6/ip6_udp_tunnel.c
+++ b/net/ipv6/ip6_udp_tunnel.c
@@ -74,14 +74,16 @@  int udp_sock_create6(struct net *net, struct udp_port_cfg *cfg,
 }
 EXPORT_SYMBOL_GPL(udp_sock_create6);
 
-void udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sock *sk,
-			  struct sk_buff *skb,
-			  struct net_device *dev,
-			  const struct in6_addr *saddr,
-			  const struct in6_addr *daddr,
-			  __u8 prio, __u8 ttl, __be32 label,
-			  __be16 src_port, __be16 dst_port, bool nocheck,
-			  u16 ip6cb_flags)
+static void __udp_tunnel6_xmit_skb(struct dst_entry *dst,
+				   struct sock *sk,
+				   struct sk_buff *skb,
+				   struct net_device *dev,
+				   const struct in6_addr *saddr,
+				   const struct in6_addr *daddr,
+				   __u8 prio, __u8 ttl, __be32 label,
+				   __be16 src_port, __be16 dst_port,
+				   bool nocheck,
+				   u16 ip6cb_flags)
 {
 	struct udphdr *uh;
 	struct ipv6hdr *ip6h;
@@ -95,8 +97,6 @@  void udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sock *sk,
 
 	uh->len = htons(skb->len);
 
-	skb_dst_set(skb, dst);
-
 	udp6_set_csum(nocheck, skb, saddr, daddr, skb->len);
 
 	__skb_push(skb, sizeof(*ip6h));
@@ -111,8 +111,39 @@  void udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sock *sk,
 
 	ip6tunnel_xmit(sk, skb, dev, ip6cb_flags);
 }
+
+void udp_tunnel6_xmit_skb(struct dst_entry *dst, struct sock *sk,
+			  struct sk_buff *skb,
+			  struct net_device *dev,
+			  const struct in6_addr *saddr,
+			  const struct in6_addr *daddr,
+			  __u8 prio, __u8 ttl, __be32 label,
+			  __be16 src_port, __be16 dst_port, bool nocheck,
+			  u16 ip6cb_flags)
+{
+	skb_dst_set(skb, dst);
+	__udp_tunnel6_xmit_skb(dst, sk, skb, dev, saddr, daddr,
+			       prio, ttl, label, src_port, dst_port,
+			       nocheck, ip6cb_flags);
+}
 EXPORT_SYMBOL_GPL(udp_tunnel6_xmit_skb);
 
+void udp_tunnel6_xmit_skb_noref(struct dst_entry *dst,
+				struct sock *sk, struct sk_buff *skb,
+				struct net_device *dev,
+				const struct in6_addr *saddr,
+				const struct in6_addr *daddr,
+				__u8 prio, __u8 ttl, __be32 label,
+				__be16 src_port, __be16 dst_port,
+				bool nocheck, u16 ip6cb_flags)
+{
+	skb_dst_set_noref(skb, dst);
+	__udp_tunnel6_xmit_skb(dst, sk, skb, dev, saddr, daddr,
+			       prio, ttl, label, src_port, dst_port,
+			       nocheck, ip6cb_flags);
+}
+EXPORT_SYMBOL_GPL(udp_tunnel6_xmit_skb_noref);
+
 /**
  *      udp_tunnel6_dst_lookup - perform route lookup on UDP tunnel
  *      @skb: Packet for which lookup is done