From: Felix Fietkau <nbd@nbd.name>
Date: Sat, 13 Aug 2022 12:55:02 +0000 (+0200)
Subject: bpf_skb_utils: fix skb parsing on older kernels
X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=3e1d996021c51dbbfeb3121570c115236122858d;p=project%2Funetd.git

bpf_skb_utils: fix skb parsing on older kernels

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---

diff --git a/bpf_skb_utils.h b/bpf_skb_utils.h
index 4953c86..643803d 100644
--- a/bpf_skb_utils.h
+++ b/bpf_skb_utils.h
@@ -56,6 +56,12 @@ static __always_inline struct ethhdr *
 skb_parse_ethernet(struct skb_parser_info *info)
 {
 	struct ethhdr *eth;
+	int len;
+
+	len = sizeof(*eth) + 2 * sizeof(struct vlan_hdr) + sizeof(struct ipv6hdr);
+	if (len > info->skb->len)
+		len = info->skb->len;
+	bpf_skb_pull_data(info->skb, len);
 
 	eth = skb_info_ptr(info, sizeof(*eth));
 	if (!eth)