Helper function bpf_skb_change_proto
Definition
Copyright (c) 2015 The Libbpf Authors. All rights reserved.
Change the protocol of the skb to proto. Currently supported are transition from IPv4 to IPv6, and from IPv6 to IPv4. The helper takes care of the groundwork for the transition, including resizing the socket buffer. The eBPF program is expected to fill the new headers, if any, via skb_store_bytes() and to recompute the checksums with bpf_l3_csum_replace() and bpf_l4_csum_replace\ (). The main case for this helper is to perform NAT64 operations out of an eBPF program.
Internally, the GSO type is marked as dodgy so that headers are checked and segments are recalculated by the GSO/GRO engine. The size for GSO target is adapted as well.
All values for flags are reserved for future usage, and must be left at zero.
A call to this helper is susceptible to change the underlying packet buffer. Therefore, at load time, all checks on pointers previously done by the verifier are invalidated and must be performed again, if the helper is used in combination with direct packet access.
Returns
0 on success, or a negative error in case of failure.
static long (* const bpf_skb_change_proto)(struct __sk_buff *skb, __be16 proto, __u64 flags) = (void *) 31;
Usage
Docs could be improved
This part of the docs is incomplete, contributions are very welcome
Program types
This helper call can be used in the following program types:
Example
Docs could be improved
This part of the docs is incomplete, contributions are very welcome