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 4953c86ca3b78cd00e905a34efb9663b40329050..643803dd3fc8b384881c42c245b9e0751d2b3016 100644 (file)
--- 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)