#include <linux/bpf.h> #include <linux/if_ether.h> #include <linux/pkt_cls.h> #include "bpf_helpers.h" #define __round_mask(x, y) ((__typeof__(x))((y) - 1)) #define round_up(x, y) ((((x) - 1) | __round_mask(x, y)) + 1) #define ctx_ptr(ctx, mem) (void *)(unsigned long)ctx->mem SEC("t") int ing_cls(struct __sk_buff *ctx) { __u8 *data, *data_meta, *data_end; __u32 diff = 0; data_meta = ctx_ptr(ctx, data_meta); data_end = ctx_ptr(ctx, data_end); data = ctx_ptr(ctx, data); if (data + ETH_ALEN > data_end || data_meta + round_up(ETH_ALEN, 4) > data) return TC_ACT_SHOT; diff |= ((__u32 *)data_meta)[0] ^ ((__u32 *)data)[0]; diff |= ((__u16 *)data_meta)[2] ^ ((__u16 *)data)[2]; return diff ? TC_ACT_SHOT : TC_ACT_OK; } SEC("x") int ing_xdp(struct xdp_md *ctx) { __u8 *data, *data_meta, *data_end; int ret; ret = bpf_xdp_adjust_meta(ctx, -round_up(ETH_ALEN, 4)); if (ret < 0) return XDP_DROP; data_meta = ctx_ptr(ctx, data_meta); data_end = ctx_ptr(ctx, data_end); data = ctx_ptr(ctx, data); if (data + ETH_ALEN > data_end || data_meta + round_up(ETH_ALEN, 4) > data) return XDP_DROP; __builtin_memcpy(data_meta, data, ETH_ALEN); return XDP_PASS; } char _license[] SEC("license") = "GPL";