mirrors/linux
2
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2026-08-28 05:14:41 -04:00
Code Issues Packages Projects Releases Wiki Activity

bpf: Add BPF_F_ADJ_ROOM_DECAP_* flags for tunnel decapsulation

Browse Source 
Add new bpf_skb_adjust_room() decapsulation flags:

- BPF_F_ADJ_ROOM_DECAP_L4_GRE
- BPF_F_ADJ_ROOM_DECAP_L4_UDP
- BPF_F_ADJ_ROOM_DECAP_IPXIP4
- BPF_F_ADJ_ROOM_DECAP_IPXIP6

These flags let BPF programs describe which tunnel layer is being
removed, so later changes can update tunnel-related GSO state
accordingly during decapsulation.

This patch only introduces the UAPI flag definitions and helper
documentation.

Co-developed-by: Max Tottenham <mtottenh@akamai.com>
Co-developed-by: Anna Glasgall <aglasgal@akamai.com>
Signed-off-by: Max Tottenham <mtottenh@akamai.com>
Signed-off-by: Anna Glasgall <aglasgal@akamai.com>
Signed-off-by: Nick Hudson <nhudson@akamai.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/bpf/20260812083115.73100-4-nhudson@akamai.com
This commit is contained in:
Nick Hudson
2026-08-12 09:31:12 +01:00
committed by Daniel Borkmann
parent 7b2ea1151e
commit da199070bc
2 changed files with 64 additions and 4 deletions
Download Patch File Download Diff File Expand all files Collapse all files

34
include/uapi/linux/bpf.h
View File

@@ -3038,8 +3038,34 @@ union bpf_attr {
*
* * **BPF_F_ADJ_ROOM_DECAP_L3_IPV4**,
* **BPF_F_ADJ_ROOM_DECAP_L3_IPV6**:
* Indicate the new IP header version after decapsulating the outer
* IP header. Used when the inner and outer IP versions are different.
* Indicate the new IP header version after decapsulating the
* outer IP header. Used when the inner and outer IP versions
* are different. These flags only trigger a protocol change
* without clearing any tunnel-specific GSO flags.
*
* * **BPF_F_ADJ_ROOM_DECAP_L4_GRE**:
* Clear GRE tunnel GSO flags (SKB_GSO_GRE and SKB_GSO_GRE_CSUM)
* when decapsulating a GRE tunnel.
*
* * **BPF_F_ADJ_ROOM_DECAP_L4_UDP**:
* Clear UDP tunnel GSO flags (SKB_GSO_UDP_TUNNEL and
* SKB_GSO_UDP_TUNNEL_CSUM) when decapsulating a UDP tunnel.
*
* * **BPF_F_ADJ_ROOM_DECAP_IPXIP4**:
* Clear IPIP/SIT tunnel GSO flag (SKB_GSO_IPXIP4) when decapsulating
* a tunnel with an outer IPv4 header (IPv4-in-IPv4 or IPv6-in-IPv4).
*
* * **BPF_F_ADJ_ROOM_DECAP_IPXIP6**:
* Clear IPv6 encapsulation tunnel GSO flag (SKB_GSO_IPXIP6) when
* decapsulating a tunnel with an outer IPv6 header (IPv6-in-IPv6
* or IPv4-in-IPv6).
*
* When using the decapsulation flags above, the skb->encapsulation
* flag is automatically cleared if all tunnel-specific GSO flags
* (SKB_GSO_UDP_TUNNEL, SKB_GSO_UDP_TUNNEL_CSUM, SKB_GSO_GRE,
* SKB_GSO_GRE_CSUM, SKB_GSO_IPXIP4, SKB_GSO_IPXIP6) have been
* removed from the packet. This handles cases where all tunnel
* layers have been decapsulated.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
@@ -6293,6 +6319,10 @@ enum bpf_adj_room_flags {
BPF_F_ADJ_ROOM_ENCAP_L2_ETH = (1ULL << 6),
BPF_F_ADJ_ROOM_DECAP_L3_IPV4 = (1ULL << 7),
BPF_F_ADJ_ROOM_DECAP_L3_IPV6 = (1ULL << 8),
BPF_F_ADJ_ROOM_DECAP_L4_GRE = (1ULL << 9),
BPF_F_ADJ_ROOM_DECAP_L4_UDP = (1ULL << 10),
BPF_F_ADJ_ROOM_DECAP_IPXIP4 = (1ULL << 11),
BPF_F_ADJ_ROOM_DECAP_IPXIP6 = (1ULL << 12),
};
enum {

34
tools/include/uapi/linux/bpf.h
View File

@@ -3038,8 +3038,34 @@ union bpf_attr {
*
* * **BPF_F_ADJ_ROOM_DECAP_L3_IPV4**,
* **BPF_F_ADJ_ROOM_DECAP_L3_IPV6**:
* Indicate the new IP header version after decapsulating the outer
* IP header. Used when the inner and outer IP versions are different.
* Indicate the new IP header version after decapsulating the
* outer IP header. Used when the inner and outer IP versions
* are different. These flags only trigger a protocol change
* without clearing any tunnel-specific GSO flags.
*
* * **BPF_F_ADJ_ROOM_DECAP_L4_GRE**:
* Clear GRE tunnel GSO flags (SKB_GSO_GRE and SKB_GSO_GRE_CSUM)
* when decapsulating a GRE tunnel.
*
* * **BPF_F_ADJ_ROOM_DECAP_L4_UDP**:
* Clear UDP tunnel GSO flags (SKB_GSO_UDP_TUNNEL and
* SKB_GSO_UDP_TUNNEL_CSUM) when decapsulating a UDP tunnel.
*
* * **BPF_F_ADJ_ROOM_DECAP_IPXIP4**:
* Clear IPIP/SIT tunnel GSO flag (SKB_GSO_IPXIP4) when decapsulating
* a tunnel with an outer IPv4 header (IPv4-in-IPv4 or IPv6-in-IPv4).
*
* * **BPF_F_ADJ_ROOM_DECAP_IPXIP6**:
* Clear IPv6 encapsulation tunnel GSO flag (SKB_GSO_IPXIP6) when
* decapsulating a tunnel with an outer IPv6 header (IPv6-in-IPv6
* or IPv4-in-IPv6).
*
* When using the decapsulation flags above, the skb->encapsulation
* flag is automatically cleared if all tunnel-specific GSO flags
* (SKB_GSO_UDP_TUNNEL, SKB_GSO_UDP_TUNNEL_CSUM, SKB_GSO_GRE,
* SKB_GSO_GRE_CSUM, SKB_GSO_IPXIP4, SKB_GSO_IPXIP6) have been
* removed from the packet. This handles cases where all tunnel
* layers have been decapsulated.
*
* A call to this helper is susceptible to change the underlying
* packet buffer. Therefore, at load time, all checks on pointers
@@ -6293,6 +6319,10 @@ enum bpf_adj_room_flags {
BPF_F_ADJ_ROOM_ENCAP_L2_ETH = (1ULL << 6),
BPF_F_ADJ_ROOM_DECAP_L3_IPV4 = (1ULL << 7),
BPF_F_ADJ_ROOM_DECAP_L3_IPV6 = (1ULL << 8),
BPF_F_ADJ_ROOM_DECAP_L4_GRE = (1ULL << 9),
BPF_F_ADJ_ROOM_DECAP_L4_UDP = (1ULL << 10),
BPF_F_ADJ_ROOM_DECAP_IPXIP4 = (1ULL << 11),
BPF_F_ADJ_ROOM_DECAP_IPXIP6 = (1ULL << 12),
};
enum {