diff options
| -rw-r--r-- | samples/bpf/Makefile | 4 | ||||
| -rw-r--r-- | samples/bpf/tracex2_kern.c | 86 | ||||
| -rw-r--r-- | samples/bpf/tracex2_user.c | 95 |
3 files changed, 185 insertions, 0 deletions
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index 51f6f01e5a3a..6dd272143733 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -7,6 +7,7 @@ hostprogs-y += sock_example hostprogs-y += sockex1 hostprogs-y += sockex2 hostprogs-y += tracex1 +hostprogs-y += tracex2 test_verifier-objs := test_verifier.o libbpf.o test_maps-objs := test_maps.o libbpf.o @@ -14,12 +15,14 @@ sock_example-objs := sock_example.o libbpf.o sockex1-objs := bpf_load.o libbpf.o sockex1_user.o sockex2-objs := bpf_load.o libbpf.o sockex2_user.o tracex1-objs := bpf_load.o libbpf.o tracex1_user.o +tracex2-objs := bpf_load.o libbpf.o tracex2_user.o # Tell kbuild to always build the programs always := $(hostprogs-y) always += sockex1_kern.o always += sockex2_kern.o always += tracex1_kern.o +always += tracex2_kern.o HOSTCFLAGS += -I$(objtree)/usr/include @@ -27,6 +30,7 @@ HOSTCFLAGS_bpf_load.o += -I$(objtree)/usr/include -Wno-unused-variable HOSTLOADLIBES_sockex1 += -lelf HOSTLOADLIBES_sockex2 += -lelf HOSTLOADLIBES_tracex1 += -lelf +HOSTLOADLIBES_tracex2 += -lelf # point this to your LLVM backend with bpf support LLC=$(srctree)/tools/bpf/llvm/bld/Debug+Asserts/bin/llc diff --git a/samples/bpf/tracex2_kern.c b/samples/bpf/tracex2_kern.c new file mode 100644 index 000000000000..19ec1cfc45db --- /dev/null +++ b/samples/bpf/tracex2_kern.c @@ -0,0 +1,86 @@ +/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + */ +#include <linux/skbuff.h> +#include <linux/netdevice.h> +#include <linux/version.h> +#include <uapi/linux/bpf.h> +#include "bpf_helpers.h" + +struct bpf_map_def SEC("maps") my_map = { + .type = BPF_MAP_TYPE_HASH, + .key_size = sizeof(long), + .value_size = sizeof(long), + .max_entries = 1024, +}; + +/* kprobe is NOT a stable ABI. If kernel internals change this bpf+kprobe + * example will no longer be meaningful + */ +SEC("kprobe/kfree_skb") +int bpf_prog2(struct pt_regs *ctx) +{ + long loc = 0; + long init_val = 1; + long *value; + + /* x64 specific: read ip of kfree_skb caller. + * non-portable version of __builtin_return_address(0) + */ + bpf_probe_read(&loc, sizeof(loc), (void *)ctx->sp); + + value = bpf_map_lookup_elem(&my_map, &loc); + if (value) + *value += 1; + else + bpf_map_update_elem(&my_map, &loc, &init_val, BPF_ANY); + return 0; +} + +static unsigned int log2(unsigned int v) +{ + unsigned int r; + unsigned int shift; + + r = (v > 0xFFFF) << 4; v >>= r; + shift = (v > 0xFF) << 3; v >>= shift; r |= shift; + shift = (v > 0xF) << 2; v >>= shift; r |= shift; + shift = (v > 0x3) << 1; v >>= shift; r |= shift; + r |= (v >> 1); + return r; +} + +static unsigned int log2l(unsigned long v) +{ + unsigned int hi = v >> 32; + if (hi) + return log2(hi) + 32; + else + return log2(v); +} + +struct bpf_map_def SEC("maps") my_hist_map = { + .type = BPF_MAP_TYPE_ARRAY, + .key_size = sizeof(u32), + .value_size = sizeof(long), + .max_entries = 64, +}; + +SEC("kprobe/sys_write") +int bpf_prog3(struct pt_regs *ctx) +{ + long write_size = ctx->dx; /* arg3 */ + long init_val = 1; + long *value; + u32 index = log2l(write_size); + + value = bpf_map_lookup_elem(&my_hist_map, &index); + if (value) + __sync_fetch_and_add(value, 1); + return 0; +} +char _license[] SEC("license") = "GPL"; +u32 _version SEC("version") = LINUX_VERSION_CODE; diff --git a/samples/bpf/tracex2_user.c b/samples/bpf/tracex2_user.c new file mode 100644 index 000000000000..91b8d0896fbb --- /dev/null +++ b/samples/bpf/tracex2_user.c @@ -0,0 +1,95 @@ +#include <stdio.h> +#include <unistd.h> +#include <stdlib.h> +#include <signal.h> +#include <linux/bpf.h> +#include "libbpf.h" +#include "bpf_load.h" + +#define MAX_INDEX 64 +#define MAX_STARS 38 + +static void stars(char *str, long val, long max, int width) +{ + int i; + + for (i = 0; i < (width * val / max) - 1 && i < width - 1; i++) + str[i] = '*'; + if (val > max) + str[i - 1] = '+'; + str[i] = '\0'; +} + +static void print_hist(int fd) +{ + int key; + long value; + long data[MAX_INDEX] = {}; + char starstr[MAX_STARS]; + int i; + int max_ind = -1; + long max_value = 0; + + for (key = 0; key < MAX_INDEX; key++) { + bpf_lookup_elem(fd, &key, &value); + data[key] = value; + if (value && key > max_ind) + max_ind = key; + if (value > max_value) + max_value = value; + } + + printf(" syscall write() stats\n"); + printf(" byte_size : count distribution\n"); + for (i = 1; i <= max_ind + 1; i++) { + stars(starstr, data[i - 1], max_value, MAX_STARS); + printf("%8ld -> %-8ld : %-8ld |%-*s|\n", + (1l << i) >> 1, (1l << i) - 1, data[i - 1], + MAX_STARS, starstr); + } +} +static void int_exit(int sig) +{ + print_hist(map_fd[1]); + exit(0); +} + +int main(int ac, char **argv) +{ + char filename[256]; + long key, next_key, value; + FILE *f; + int i; + + snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); + + signal(SIGINT, int_exit); + + /* start 'ping' in the background to have some kfree_skb events */ + f = popen("ping -c5 localhost", "r"); + (void) f; + + /* start 'dd' in the background to have plenty of 'write' syscalls */ + f = popen("dd if=/dev/zero of=/dev/null count=5000000", "r"); + (void) f; + + if (load_bpf_file(filename)) { + printf("%s", bpf_log_buf); + return 1; + } + + for (i = 0; i < 5; i++) { + key = 0; + while (bpf_get_next_key(map_fd[0], &key, &next_key) == 0) { + bpf_lookup_elem(map_fd[0], &next_key, &value); + printf("location 0x%lx count %ld\n", next_key, value); + key = next_key; + } + if (key) + printf("\n"); + sleep(1); + } + print_hist(map_fd[1]); + + return 0; +} |