[30/38] backports: add skb_get_dsfield()

Commit Message

Johannes Berg Oct. 11, 2022, 9:04 p.m. UTC

From: Johannes Berg <[e-mail]>

That may also require skb_protocol() and skb_vlan_tag_present()

Signed-off-by: Johannes Berg <[e-mail]>
---
 backport/backport-include/net/inet_ecn.h | 66 ++++++++++++++++++++++++
 1 file changed, 66 insertions(+)
 create mode 100644 backport/backport-include/net/inet_ecn.h

Patch

diff --git a/backport/backport-include/net/inet_ecn.h b/backport/backport-include/net/inet_ecn.h
new file mode 100644
index 000000000000..df83d3e179ec
--- /dev/null
+++ b/backport/backport-include/net/inet_ecn.h
@@ -0,0 +1,66 @@ 
+#ifndef __BACKPORT_NET_INET_ECN_H
+#define __BACKPORT_NET_INET_ECN_H
+#include_next <net/inet_ecn.h>
+#include <linux/version.h>
+#include <linux/if_vlan.h>
+
+#ifndef skb_vlan_tag_present
+#define skb_vlan_tag_present(__skb)       ((__skb)->vlan_present)
+#endif
+
+#if LINUX_VERSION_IS_LESS(5,7,10) &&			\
+	!LINUX_VERSION_IN_RANGE(4,14,212, 4,15,0) &&	\
+	!LINUX_VERSION_IN_RANGE(4,19,134, 4,20,0) &&	\
+	!LINUX_VERSION_IN_RANGE(4,4,248, 4,5,0) &&	\
+	!LINUX_VERSION_IN_RANGE(4,9,248, 4,10,0) &&	\
+	!LINUX_VERSION_IN_RANGE(5,4,53, 5,5,0)
+/* A getter for the SKB protocol field which will handle VLAN tags consistently
+ * whether VLAN acceleration is enabled or not.
+ */
+static inline __be16 skb_protocol(const struct sk_buff *skb, bool skip_vlan)
+{
+	unsigned int offset = skb_mac_offset(skb) + sizeof(struct ethhdr);
+	__be16 proto = skb->protocol;
+
+	if (!skip_vlan)
+		/* VLAN acceleration strips the VLAN header from the skb and
+		 * moves it to skb->vlan_proto
+		 */
+		return skb_vlan_tag_present(skb) ? skb->vlan_proto : proto;
+
+	while (eth_type_vlan(proto)) {
+		struct vlan_hdr vhdr, *vh;
+
+		vh = skb_header_pointer(skb, offset, sizeof(vhdr), &vhdr);
+		if (!vh)
+			break;
+
+		proto = vh->h_vlan_encapsulated_proto;
+		offset += sizeof(vhdr);
+	}
+
+	return proto;
+}
+#endif
+
+#if LINUX_VERSION_IS_LESS(5,16,0)
+#define skb_get_dsfield LINUX_BACKPORT(skb_get_dsfield)
+static inline int skb_get_dsfield(struct sk_buff *skb)
+{
+	switch (skb_protocol(skb, true)) {
+	case cpu_to_be16(ETH_P_IP):
+		if (!pskb_network_may_pull(skb, sizeof(struct iphdr)))
+			break;
+		return ipv4_get_dsfield(ip_hdr(skb));
+
+	case cpu_to_be16(ETH_P_IPV6):
+		if (!pskb_network_may_pull(skb, sizeof(struct ipv6hdr)))
+			break;
+		return ipv6_get_dsfield(ipv6_hdr(skb));
+	}
+
+	return -1;
+}
+#endif
+
+#endif /* __BACKPORT_NET_INET_ECN_H */