bpf/progs/test_xdp_adjust_tail_grow.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 #include <linux/bpf.h>
0003 #include <bpf/bpf_helpers.h>
0004
0005 SEC("xdp")
0006 int _xdp_adjust_tail_grow(struct xdp_md *xdp)
0007 {
0008     void *data_end = (void *)(long)xdp->data_end;
0009     void *data = (void *)(long)xdp->data;
0010     int data_len = bpf_xdp_get_buff_len(xdp);
0011     int offset = 0;
0012
0013     /* Data length determine test case */
0014
0015     if (data_len == 54) { /* sizeof(pkt_v4) */
0016         offset = 4096; /* test too large offset */
0017     } else if (data_len == 74) { /* sizeof(pkt_v6) */
0018         offset = 40;
0019     } else if (data_len == 64) {
0020         offset = 128;
0021     } else if (data_len == 128) {
0022         /* Max tail grow 3520 */
0023         offset = 4096 - 256 - 320 - data_len;
0024     } else if (data_len == 9000) {
0025         offset = 10;
0026     } else if (data_len == 9001) {
0027         offset = 4096;
0028     } else {
0029         return XDP_ABORTED; /* No matching test */
0030     }
0031
0032     if (bpf_xdp_adjust_tail(xdp, offset))
0033         return XDP_DROP;
0034     return XDP_TX;
0035 }
0036
0037 char _license[] SEC("license") = "GPL";