1 // SPDX-License-Identifier: GPL-2.0 2 #include <error.h> 3 #include <errno.h> 4 #include <getopt.h> 5 #include <stdio.h> 6 #include <stdlib.h> 7 #include <string.h> 8 #include <sys/stat.h> 9 #include <fcntl.h> 10 #include <unistd.h> 11 #include <bpf/bpf.h> 12 #include <bpf/libbpf.h> 13 14 #include "flow_dissector_load.h" 15 16 const char *cfg_pin_path = "/sys/fs/bpf/flow_dissector"; 17 const char *cfg_map_name = "jmp_table"; 18 bool cfg_attach = true; 19 char *cfg_prog_name; 20 char *cfg_path_name; 21 22 static void load_and_attach_program(void) 23 { 24 int prog_fd, ret; 25 struct bpf_object *obj; 26 27 /* Use libbpf 1.0 API mode */ 28 libbpf_set_strict_mode(LIBBPF_STRICT_ALL); 29 30 ret = bpf_flow_load(&obj, cfg_path_name, cfg_prog_name, 31 cfg_map_name, NULL, &prog_fd, NULL); 32 if (ret) 33 error(1, 0, "bpf_flow_load %s", cfg_path_name); 34 35 ret = bpf_prog_attach(prog_fd, 0 /* Ignore */, BPF_FLOW_DISSECTOR, 0); 36 if (ret) 37 error(1, 0, "bpf_prog_attach %s", cfg_path_name); 38 39 ret = bpf_object__pin(obj, cfg_pin_path); 40 if (ret) 41 error(1, 0, "bpf_object__pin %s", cfg_pin_path); 42 } 43 44 static void detach_program(void) 45 { 46 char command[64]; 47 int ret; 48 49 ret = bpf_prog_detach(0, BPF_FLOW_DISSECTOR); 50 if (ret) 51 error(1, 0, "bpf_prog_detach"); 52 53 /* To unpin, it is necessary and sufficient to just remove this dir */ 54 sprintf(command, "rm -r %s", cfg_pin_path); 55 ret = system(command); 56 if (ret) 57 error(1, errno, "%s", command); 58 } 59 60 static void parse_opts(int argc, char **argv) 61 { 62 bool attach = false; 63 bool detach = false; 64 int c; 65 66 while ((c = getopt(argc, argv, "adp:s:")) != -1) { 67 switch (c) { 68 case 'a': 69 if (detach) 70 error(1, 0, "attach/detach are exclusive"); 71 attach = true; 72 break; 73 case 'd': 74 if (attach) 75 error(1, 0, "attach/detach are exclusive"); 76 detach = true; 77 break; 78 case 'p': 79 if (cfg_path_name) 80 error(1, 0, "only one path can be given"); 81 82 cfg_path_name = optarg; 83 break; 84 case 's': 85 if (cfg_prog_name) 86 error(1, 0, "only one prog can be given"); 87 88 cfg_prog_name = optarg; 89 break; 90 } 91 } 92 93 if (detach) 94 cfg_attach = false; 95 96 if (cfg_attach && !cfg_path_name) 97 error(1, 0, "must provide a path to the BPF program"); 98 99 if (cfg_attach && !cfg_prog_name) 100 error(1, 0, "must provide a section name"); 101 } 102 103 int main(int argc, char **argv) 104 { 105 parse_opts(argc, argv); 106 if (cfg_attach) 107 load_and_attach_program(); 108 else 109 detach_program(); 110 return 0; 111 } 112