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49705c4ab3
LLVM compiler optimized out the memcpy in xdp_redirect_map_egress, which caused the Ethernet source MAC-addr to always be zero when enabling the devmap egress prog via cmdline --load-egress. Issue observed with LLVM version 14.0.0 - Shipped with Fedora 36 on target: x86_64-redhat-linux-gnu. In verbose mode print the source MAC-addr in case xdp_devmap_attached mode is used. Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/165754826292.575614.5636444052787717159.stgit@firesoul
97 lines
2.5 KiB
C
97 lines
2.5 KiB
C
/* Copyright (c) 2017 Covalent IO, Inc. http://covalent.io
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#define KBUILD_MODNAME "foo"
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#include "vmlinux.h"
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#include "xdp_sample.bpf.h"
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#include "xdp_sample_shared.h"
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/* The 2nd xdp prog on egress does not support skb mode, so we define two
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* maps, tx_port_general and tx_port_native.
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*/
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struct {
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__uint(type, BPF_MAP_TYPE_DEVMAP);
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__uint(key_size, sizeof(int));
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__uint(value_size, sizeof(int));
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__uint(max_entries, 1);
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} tx_port_general SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_DEVMAP);
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__uint(key_size, sizeof(int));
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__uint(value_size, sizeof(struct bpf_devmap_val));
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__uint(max_entries, 1);
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} tx_port_native SEC(".maps");
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/* store egress interface mac address */
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const volatile __u8 tx_mac_addr[ETH_ALEN];
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static __always_inline int xdp_redirect_map(struct xdp_md *ctx, void *redirect_map)
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{
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void *data_end = (void *)(long)ctx->data_end;
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void *data = (void *)(long)ctx->data;
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u32 key = bpf_get_smp_processor_id();
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struct ethhdr *eth = data;
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struct datarec *rec;
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u64 nh_off;
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nh_off = sizeof(*eth);
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if (data + nh_off > data_end)
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return XDP_DROP;
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rec = bpf_map_lookup_elem(&rx_cnt, &key);
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if (!rec)
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return XDP_PASS;
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NO_TEAR_INC(rec->processed);
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swap_src_dst_mac(data);
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return bpf_redirect_map(redirect_map, 0, 0);
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}
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SEC("xdp")
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int xdp_redirect_map_general(struct xdp_md *ctx)
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{
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return xdp_redirect_map(ctx, &tx_port_general);
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}
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SEC("xdp")
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int xdp_redirect_map_native(struct xdp_md *ctx)
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{
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return xdp_redirect_map(ctx, &tx_port_native);
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}
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SEC("xdp/devmap")
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int xdp_redirect_map_egress(struct xdp_md *ctx)
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{
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void *data_end = (void *)(long)ctx->data_end;
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void *data = (void *)(long)ctx->data;
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u8 *mac_addr = (u8 *) tx_mac_addr;
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struct ethhdr *eth = data;
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u64 nh_off;
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nh_off = sizeof(*eth);
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if (data + nh_off > data_end)
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return XDP_DROP;
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barrier_var(mac_addr); /* prevent optimizing out memcpy */
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__builtin_memcpy(eth->h_source, mac_addr, ETH_ALEN);
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return XDP_PASS;
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}
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/* Redirect require an XDP bpf_prog loaded on the TX device */
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SEC("xdp")
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int xdp_redirect_dummy_prog(struct xdp_md *ctx)
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{
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return XDP_PASS;
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}
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char _license[] SEC("license") = "GPL";
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