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 "bpf_rlimit.h" 15 #include "flow_dissector_load.h" 16 17 const char *cfg_pin_path = "/sys/fs/bpf/flow_dissector"; 18 const char *cfg_map_name = "jmp_table"; 19 bool cfg_attach = true; 20 char *cfg_prog_name; 21 char *cfg_path_name; 22 23 static void load_and_attach_program(void) 24 { 25 int prog_fd, ret; 26 struct bpf_object *obj; 27 28 ret = libbpf_set_strict_mode(LIBBPF_STRICT_ALL); 29 if (ret) 30 error(1, 0, "failed to enable libbpf strict mode: %d", ret); 31 32 ret = bpf_flow_load(&obj, cfg_path_name, cfg_prog_name, 33 cfg_map_name, NULL, &prog_fd, NULL); 34 if (ret) 35 error(1, 0, "bpf_flow_load %s", cfg_path_name); 36 37 ret = bpf_prog_attach(prog_fd, 0 /* Ignore */, BPF_FLOW_DISSECTOR, 0); 38 if (ret) 39 error(1, 0, "bpf_prog_attach %s", cfg_path_name); 40 41 ret = bpf_object__pin(obj, cfg_pin_path); 42 if (ret) 43 error(1, 0, "bpf_object__pin %s", cfg_pin_path); 44 } 45 46 static void detach_program(void) 47 { 48 char command[64]; 49 int ret; 50 51 ret = bpf_prog_detach(0, BPF_FLOW_DISSECTOR); 52 if (ret) 53 error(1, 0, "bpf_prog_detach"); 54 55 /* To unpin, it is necessary and sufficient to just remove this dir */ 56 sprintf(command, "rm -r %s", cfg_pin_path); 57 ret = system(command); 58 if (ret) 59 error(1, errno, "%s", command); 60 } 61 62 static void parse_opts(int argc, char **argv) 63 { 64 bool attach = false; 65 bool detach = false; 66 int c; 67 68 while ((c = getopt(argc, argv, "adp:s:")) != -1) { 69 switch (c) { 70 case 'a': 71 if (detach) 72 error(1, 0, "attach/detach are exclusive"); 73 attach = true; 74 break; 75 case 'd': 76 if (attach) 77 error(1, 0, "attach/detach are exclusive"); 78 detach = true; 79 break; 80 case 'p': 81 if (cfg_path_name) 82 error(1, 0, "only one path can be given"); 83 84 cfg_path_name = optarg; 85 break; 86 case 's': 87 if (cfg_prog_name) 88 error(1, 0, "only one prog can be given"); 89 90 cfg_prog_name = optarg; 91 break; 92 } 93 } 94 95 if (detach) 96 cfg_attach = false; 97 98 if (cfg_attach && !cfg_path_name) 99 error(1, 0, "must provide a path to the BPF program"); 100 101 if (cfg_attach && !cfg_prog_name) 102 error(1, 0, "must provide a section name"); 103 } 104 105 int main(int argc, char **argv) 106 { 107 parse_opts(argc, argv); 108 if (cfg_attach) 109 load_and_attach_program(); 110 else 111 detach_program(); 112 return 0; 113 } 114