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4b30209255
Introduce tail adjustment functionality in xskxceiver using bpf_xdp_adjust_tail(). Add `xsk_xdp_adjust_tail` to modify packet sizes and drop unmodified packets. Implement `is_adjust_tail_supported` to check helper availability. Develop packet resizing tests, including shrinking and growing scenarios, with functions for both single-buffer and multi-buffer cases. Update the test framework to handle various scenarios and adjust MTU settings. These changes enhance the testing of packet tail adjustments, improving AF_XDP framework reliability. Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com> Signed-off-by: Tushar Vyavahare <tushar.vyavahare@intel.com> Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org> Link: https://patch.msgid.link/20250410033116.173617-3-tushar.vyavahare@intel.com
123 lines
2.9 KiB
C
123 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2022 Intel */
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#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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#include <linux/if_ether.h>
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#include <linux/ip.h>
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#include <linux/errno.h>
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#include "xsk_xdp_common.h"
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struct {
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__uint(type, BPF_MAP_TYPE_XSKMAP);
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__uint(max_entries, 2);
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__uint(key_size, sizeof(int));
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__uint(value_size, sizeof(int));
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} xsk SEC(".maps");
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static unsigned int idx;
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int adjust_value = 0;
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int count = 0;
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SEC("xdp.frags") int xsk_def_prog(struct xdp_md *xdp)
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{
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return bpf_redirect_map(&xsk, 0, XDP_DROP);
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}
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SEC("xdp.frags") int xsk_xdp_drop(struct xdp_md *xdp)
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{
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/* Drop every other packet */
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if (idx++ % 2)
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return XDP_DROP;
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return bpf_redirect_map(&xsk, 0, XDP_DROP);
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}
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SEC("xdp.frags") int xsk_xdp_populate_metadata(struct xdp_md *xdp)
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{
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void *data, *data_meta;
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struct xdp_info *meta;
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int err;
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/* Reserve enough for all custom metadata. */
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err = bpf_xdp_adjust_meta(xdp, -(int)sizeof(struct xdp_info));
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if (err)
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return XDP_DROP;
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data = (void *)(long)xdp->data;
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data_meta = (void *)(long)xdp->data_meta;
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if (data_meta + sizeof(struct xdp_info) > data)
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return XDP_DROP;
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meta = data_meta;
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meta->count = count++;
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return bpf_redirect_map(&xsk, 0, XDP_DROP);
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}
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SEC("xdp") int xsk_xdp_shared_umem(struct xdp_md *xdp)
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{
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void *data = (void *)(long)xdp->data;
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void *data_end = (void *)(long)xdp->data_end;
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struct ethhdr *eth = data;
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if (eth + 1 > data_end)
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return XDP_DROP;
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/* Redirecting packets based on the destination MAC address */
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idx = ((unsigned int)(eth->h_dest[5])) / 2;
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if (idx > MAX_SOCKETS)
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return XDP_DROP;
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return bpf_redirect_map(&xsk, idx, XDP_DROP);
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}
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SEC("xdp.frags") int xsk_xdp_adjust_tail(struct xdp_md *xdp)
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{
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__u32 buff_len, curr_buff_len;
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int ret;
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buff_len = bpf_xdp_get_buff_len(xdp);
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if (buff_len == 0)
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return XDP_DROP;
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ret = bpf_xdp_adjust_tail(xdp, adjust_value);
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if (ret < 0) {
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/* Handle unsupported cases */
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if (ret == -EOPNOTSUPP) {
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/* Set adjust_value to -EOPNOTSUPP to indicate to userspace that this case
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* is unsupported
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*/
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adjust_value = -EOPNOTSUPP;
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return bpf_redirect_map(&xsk, 0, XDP_DROP);
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}
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return XDP_DROP;
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}
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curr_buff_len = bpf_xdp_get_buff_len(xdp);
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if (curr_buff_len != buff_len + adjust_value)
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return XDP_DROP;
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if (curr_buff_len > buff_len) {
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__u32 *pkt_data = (void *)(long)xdp->data;
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__u32 len, words_to_end, seq_num;
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len = curr_buff_len - PKT_HDR_ALIGN;
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words_to_end = len / sizeof(*pkt_data) - 1;
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seq_num = words_to_end;
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/* Convert sequence number to network byte order. Store this in the last 4 bytes of
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* the packet. Use 'adjust_value' to determine the position at the end of the
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* packet for storing the sequence number.
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*/
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seq_num = __constant_htonl(words_to_end);
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bpf_xdp_store_bytes(xdp, curr_buff_len - sizeof(seq_num), &seq_num,
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sizeof(seq_num));
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}
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return bpf_redirect_map(&xsk, 0, XDP_DROP);
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}
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char _license[] SEC("license") = "GPL";
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