From 323140389405e5d5d2020b2e3e04863d12cf3e32 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Sat, 21 Aug 2021 05:49:52 +0530 Subject: samples: bpf: Add BPF support for redirect tracepoint This adds the shared BPF file that will be used going forward for sharing tracepoint programs among XDP redirect samples. Since vmlinux.h conflicts with tools/include for READ_ONCE/WRITE_ONCE and ARRAY_SIZE, they are copied in to xdp_sample.bpf.h along with other helpers that will be required. Signed-off-by: Kumar Kartikeya Dwivedi Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20210821002010.845777-5-memxor@gmail.com --- samples/bpf/xdp_sample.bpf.c | 112 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 112 insertions(+) create mode 100644 samples/bpf/xdp_sample.bpf.c (limited to 'samples/bpf/xdp_sample.bpf.c') diff --git a/samples/bpf/xdp_sample.bpf.c b/samples/bpf/xdp_sample.bpf.c new file mode 100644 index 000000000000..e22f2a97a988 --- /dev/null +++ b/samples/bpf/xdp_sample.bpf.c @@ -0,0 +1,112 @@ +// SPDX-License-Identifier: GPL-2.0 +/* GPLv2, Copyright(c) 2017 Jesper Dangaard Brouer, Red Hat, Inc. */ +#include "xdp_sample.bpf.h" + +#include +#include +#include + +array_map rx_cnt SEC(".maps"); +array_map redir_err_cnt SEC(".maps"); + +const volatile int nr_cpus = 0; + +/* These can be set before loading so that redundant comparisons can be DCE'd by + * the verifier, and only actual matches are tried after loading tp_btf program. + * This allows sample to filter tracepoint stats based on net_device. + */ +const volatile int from_match[32] = {}; +const volatile int to_match[32] = {}; + +/* Find if b is part of set a, but if a is empty set then evaluate to true */ +#define IN_SET(a, b) \ + ({ \ + bool __res = !(a)[0]; \ + for (int i = 0; i < ARRAY_SIZE(a) && (a)[i]; i++) { \ + __res = (a)[i] == (b); \ + if (__res) \ + break; \ + } \ + __res; \ + }) + +static __always_inline __u32 xdp_get_err_key(int err) +{ + switch (err) { + case 0: + return 0; + case -EINVAL: + return 2; + case -ENETDOWN: + return 3; + case -EMSGSIZE: + return 4; + case -EOPNOTSUPP: + return 5; + case -ENOSPC: + return 6; + default: + return 1; + } +} + +static __always_inline int xdp_redirect_collect_stat(int from, int err) +{ + u32 cpu = bpf_get_smp_processor_id(); + u32 key = XDP_REDIRECT_ERROR; + struct datarec *rec; + u32 idx; + + if (!IN_SET(from_match, from)) + return 0; + + key = xdp_get_err_key(err); + + idx = key * nr_cpus + cpu; + rec = bpf_map_lookup_elem(&redir_err_cnt, &idx); + if (!rec) + return 0; + if (key) + NO_TEAR_INC(rec->dropped); + else + NO_TEAR_INC(rec->processed); + return 0; /* Indicate event was filtered (no further processing)*/ + /* + * Returning 1 here would allow e.g. a perf-record tracepoint + * to see and record these events, but it doesn't work well + * in-practice as stopping perf-record also unload this + * bpf_prog. Plus, there is additional overhead of doing so. + */ +} + +SEC("tp_btf/xdp_redirect_err") +int BPF_PROG(tp_xdp_redirect_err, const struct net_device *dev, + const struct bpf_prog *xdp, const void *tgt, int err, + const struct bpf_map *map, u32 index) +{ + return xdp_redirect_collect_stat(dev->ifindex, err); +} + +SEC("tp_btf/xdp_redirect_map_err") +int BPF_PROG(tp_xdp_redirect_map_err, const struct net_device *dev, + const struct bpf_prog *xdp, const void *tgt, int err, + const struct bpf_map *map, u32 index) +{ + return xdp_redirect_collect_stat(dev->ifindex, err); +} + +SEC("tp_btf/xdp_redirect") +int BPF_PROG(tp_xdp_redirect, const struct net_device *dev, + const struct bpf_prog *xdp, const void *tgt, int err, + const struct bpf_map *map, u32 index) +{ + return xdp_redirect_collect_stat(dev->ifindex, err); +} + +SEC("tp_btf/xdp_redirect_map") +int BPF_PROG(tp_xdp_redirect_map, const struct net_device *dev, + const struct bpf_prog *xdp, const void *tgt, int err, + const struct bpf_map *map, u32 index) +{ + return xdp_redirect_collect_stat(dev->ifindex, err); +} -- cgit v1.2.3