diff options
| -rw-r--r-- | samples/bpf/Makefile | 4 | ||||
| -rw-r--r-- | samples/bpf/test_probe_write_user_kern.c | 52 | ||||
| -rw-r--r-- | samples/bpf/test_probe_write_user_user.c | 78 |
3 files changed, 134 insertions, 0 deletions
diff --git a/samples/bpf/Makefile b/samples/bpf/Makefile index d2d2b35c67eb..90ebf7d35c07 100644 --- a/samples/bpf/Makefile +++ b/samples/bpf/Makefile @@ -14,6 +14,7 @@ hostprogs-y += tracex3 hostprogs-y += tracex4 hostprogs-y += tracex5 hostprogs-y += tracex6 +hostprogs-y += test_probe_write_user hostprogs-y += trace_output hostprogs-y += lathist hostprogs-y += offwaketime @@ -37,6 +38,7 @@ tracex3-objs := bpf_load.o libbpf.o tracex3_user.o tracex4-objs := bpf_load.o libbpf.o tracex4_user.o tracex5-objs := bpf_load.o libbpf.o tracex5_user.o tracex6-objs := bpf_load.o libbpf.o tracex6_user.o +test_probe_write_user-objs := bpf_load.o libbpf.o test_probe_write_user_user.o trace_output-objs := bpf_load.o libbpf.o trace_output_user.o lathist-objs := bpf_load.o libbpf.o lathist_user.o offwaketime-objs := bpf_load.o libbpf.o offwaketime_user.o @@ -59,6 +61,7 @@ always += tracex3_kern.o always += tracex4_kern.o always += tracex5_kern.o always += tracex6_kern.o +always += test_probe_write_user_kern.o always += trace_output_kern.o always += tcbpf1_kern.o always += lathist_kern.o @@ -85,6 +88,7 @@ HOSTLOADLIBES_tracex3 += -lelf HOSTLOADLIBES_tracex4 += -lelf -lrt HOSTLOADLIBES_tracex5 += -lelf HOSTLOADLIBES_tracex6 += -lelf +HOSTLOADLIBES_test_probe_write_user += -lelf HOSTLOADLIBES_trace_output += -lelf -lrt HOSTLOADLIBES_lathist += -lelf HOSTLOADLIBES_offwaketime += -lelf diff --git a/samples/bpf/test_probe_write_user_kern.c b/samples/bpf/test_probe_write_user_kern.c new file mode 100644 index 000000000000..3a677c807044 --- /dev/null +++ b/samples/bpf/test_probe_write_user_kern.c @@ -0,0 +1,52 @@ +/* Copyright (c) 2016 Sargun Dhillon <sargun@sargun.me> + * + * 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 <uapi/linux/bpf.h> +#include <linux/version.h> +#include "bpf_helpers.h" + +struct bpf_map_def SEC("maps") dnat_map = { + .type = BPF_MAP_TYPE_HASH, + .key_size = sizeof(struct sockaddr_in), + .value_size = sizeof(struct sockaddr_in), + .max_entries = 256, +}; + +/* kprobe is NOT a stable ABI + * kernel functions can be removed, renamed or completely change semantics. + * Number of arguments and their positions can change, etc. + * In such case this bpf+kprobe example will no longer be meaningful + * + * This example sits on a syscall, and the syscall ABI is relatively stable + * of course, across platforms, and over time, the ABI may change. + */ +SEC("kprobe/sys_connect") +int bpf_prog1(struct pt_regs *ctx) +{ + struct sockaddr_in new_addr, orig_addr = {}; + struct sockaddr_in *mapped_addr; + void *sockaddr_arg = (void *)PT_REGS_PARM2(ctx); + int sockaddr_len = (int)PT_REGS_PARM3(ctx); + + if (sockaddr_len > sizeof(orig_addr)) + return 0; + + if (bpf_probe_read(&orig_addr, sizeof(orig_addr), sockaddr_arg) != 0) + return 0; + + mapped_addr = bpf_map_lookup_elem(&dnat_map, &orig_addr); + if (mapped_addr != NULL) { + memcpy(&new_addr, mapped_addr, sizeof(new_addr)); + bpf_probe_write_user(sockaddr_arg, &new_addr, + sizeof(new_addr)); + } + return 0; +} + +char _license[] SEC("license") = "GPL"; +u32 _version SEC("version") = LINUX_VERSION_CODE; diff --git a/samples/bpf/test_probe_write_user_user.c b/samples/bpf/test_probe_write_user_user.c new file mode 100644 index 000000000000..a44bf347bedd --- /dev/null +++ b/samples/bpf/test_probe_write_user_user.c @@ -0,0 +1,78 @@ +#include <stdio.h> +#include <assert.h> +#include <linux/bpf.h> +#include <unistd.h> +#include "libbpf.h" +#include "bpf_load.h" +#include <sys/socket.h> +#include <string.h> +#include <netinet/in.h> +#include <arpa/inet.h> + +int main(int ac, char **argv) +{ + int serverfd, serverconnfd, clientfd; + socklen_t sockaddr_len; + struct sockaddr serv_addr, mapped_addr, tmp_addr; + struct sockaddr_in *serv_addr_in, *mapped_addr_in, *tmp_addr_in; + char filename[256]; + char *ip; + + serv_addr_in = (struct sockaddr_in *)&serv_addr; + mapped_addr_in = (struct sockaddr_in *)&mapped_addr; + tmp_addr_in = (struct sockaddr_in *)&tmp_addr; + + snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]); + + if (load_bpf_file(filename)) { + printf("%s", bpf_log_buf); + return 1; + } + + assert((serverfd = socket(AF_INET, SOCK_STREAM, 0)) > 0); + assert((clientfd = socket(AF_INET, SOCK_STREAM, 0)) > 0); + + /* Bind server to ephemeral port on lo */ + memset(&serv_addr, 0, sizeof(serv_addr)); + serv_addr_in->sin_family = AF_INET; + serv_addr_in->sin_port = 0; + serv_addr_in->sin_addr.s_addr = htonl(INADDR_LOOPBACK); + + assert(bind(serverfd, &serv_addr, sizeof(serv_addr)) == 0); + + sockaddr_len = sizeof(serv_addr); + assert(getsockname(serverfd, &serv_addr, &sockaddr_len) == 0); + ip = inet_ntoa(serv_addr_in->sin_addr); + printf("Server bound to: %s:%d\n", ip, ntohs(serv_addr_in->sin_port)); + + memset(&mapped_addr, 0, sizeof(mapped_addr)); + mapped_addr_in->sin_family = AF_INET; + mapped_addr_in->sin_port = htons(5555); + mapped_addr_in->sin_addr.s_addr = inet_addr("255.255.255.255"); + + assert(!bpf_update_elem(map_fd[0], &mapped_addr, &serv_addr, BPF_ANY)); + + assert(listen(serverfd, 5) == 0); + + ip = inet_ntoa(mapped_addr_in->sin_addr); + printf("Client connecting to: %s:%d\n", + ip, ntohs(mapped_addr_in->sin_port)); + assert(connect(clientfd, &mapped_addr, sizeof(mapped_addr)) == 0); + + sockaddr_len = sizeof(tmp_addr); + ip = inet_ntoa(tmp_addr_in->sin_addr); + assert((serverconnfd = accept(serverfd, &tmp_addr, &sockaddr_len)) > 0); + printf("Server received connection from: %s:%d\n", + ip, ntohs(tmp_addr_in->sin_port)); + + sockaddr_len = sizeof(tmp_addr); + assert(getpeername(clientfd, &tmp_addr, &sockaddr_len) == 0); + ip = inet_ntoa(tmp_addr_in->sin_addr); + printf("Client's peer address: %s:%d\n", + ip, ntohs(tmp_addr_in->sin_port)); + + /* Is the server's getsockname = the socket getpeername */ + assert(memcmp(&serv_addr, &tmp_addr, sizeof(struct sockaddr_in)) == 0); + + return 0; +} |