Tizian-Maxime-Weigt/l3-l4-forwarding-in-xdp
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Adding vLan forwarding and offloading Support

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Adding vLan forwarding and offloading Support for XDP offloading.
This commit is contained in:
Tizian Maxime Weigt 2025-10-27 21:43:40 +00:00
parent 76e8efa0b7
commit aef70ec801
1 changed files with 43 additions and 1 deletions
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42
main.c
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@ -22,6 +22,7 @@
#endif
#define IPV6_FLOWINFO_MASK bpf_htonl(0x0FFFFFFF)
#define VLAN_MAX_DEPTH 2 /* Support double-tagged VLANs */
/* Forwarding ports */
struct {
@ -35,14 +36,19 @@ struct {
struct flow_key {
__u8 proto;
__u8 pad[3]; /* alignment */
__u16 vlan_id; /* VLAN ID (0 if untagged) */
__u16 pad2; /* alignment */
union {
__u32 ipv4_src;
__u8 ipv6_src[16];
};
union {
__u32 ipv4_dst;
__u8 ipv6_dst[16];
};
__u16 sport;
__u16 dport;
};
@ -88,6 +94,36 @@ static __always_inline void record_stats(struct xdp_md *ctx, struct flow_key *ke
}
}
/* Parse VLAN headers and return next protocol and offset */
static __always_inline int parse_vlan(void *data, void *data_end, __u64 *nh_off, __u16 *h_proto, __u16 *vlan_id)
{
struct vlan_hdr {
__be16 h_vlan_TCI;
__be16 h_vlan_encapsulated_proto;
} *vhdr;
int i;
/* Parse up to VLAN_MAX_DEPTH VLAN headers */
#pragma unroll
for (i = 0; i < VLAN_MAX_DEPTH; i++) {
if (*h_proto != bpf_htons(ETH_P_8021Q) && *h_proto != bpf_htons(ETH_P_8021AD))
break;
vhdr = data + *nh_off;
if ((void *)(vhdr + 1) > data_end)
return -1;
/* Store the outermost VLAN ID */
if (i == 0)
*vlan_id = bpf_ntohs(vhdr->h_vlan_TCI) & 0x0FFF;
*nh_off += sizeof(*vhdr);
*h_proto = vhdr->h_vlan_encapsulated_proto;
}
return 0;
}
static __always_inline int xdp_l3fwd_flags(struct xdp_md *ctx, __u32 flags)
{
void *data_end = (void *)(long)ctx->data_end;
@ -99,6 +135,7 @@ static __always_inline int xdp_l3fwd_flags(struct xdp_md *ctx, __u32 flags)
__u16 h_proto;
__u64 nh_off;
int rc;
__u16 vlan_id = 0;
nh_off = sizeof(*eth);
if (data + nh_off > data_end)
@ -107,7 +144,12 @@ static __always_inline int xdp_l3fwd_flags(struct xdp_md *ctx, __u32 flags)
__builtin_memset(&fib_params, 0, sizeof(fib_params));
h_proto = eth->h_proto;
/* Parse VLAN headers if present */
if (parse_vlan(data, data_end, &nh_off, &h_proto, &vlan_id) < 0)
return XDP_DROP;
struct flow_key key = {};
key.vlan_id = vlan_id;
__u64 bytes = data_end - data;
if (h_proto == bpf_htons(ETH_P_IP)) {