tc/m_bpf.c

   1 /*
   2  * m_bpf.c      BPF based action module
   3  *
   4  *              This program is free software; you can redistribute it and/or
   5  *              modify it under the terms of the GNU General Public License
   6  *              as published by the Free Software Foundation; either version
   7  *              2 of the License, or (at your option) any later version.
   8  *
   9  * Authors:     Jiri Pirko <jiri@resnulli.us>
  10  *              Daniel Borkmann <daniel@iogearbox.net>
  11  */
  12
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <unistd.h>
  16 #include <string.h>
  17 #include <stdbool.h>
  18 #include <libgen.h>
  19 #include <linux/bpf.h>
  20 #include <linux/tc_act/tc_bpf.h>
  21
  22 #include "utils.h"
  23 #include "rt_names.h"
  24 #include "tc_util.h"
  25 #include "tc_bpf.h"
  26
  27 static const enum bpf_prog_type bpf_type = BPF_PROG_TYPE_SCHED_ACT;
  28
  29 static void explain(void)
  30 {
  31         fprintf(stderr, "Usage: ... bpf ...\n");
  32         fprintf(stderr, "\n");
  33         fprintf(stderr, "BPF use case:\n");
  34         fprintf(stderr, " bytecode BPF_BYTECODE\n");
  35         fprintf(stderr, " bytecode-file FILE\n");
  36         fprintf(stderr, "\n");
  37         fprintf(stderr, "eBPF use case:\n");
  38         fprintf(stderr, " object-file FILE [ section ACT_NAME ] [ export UDS_FILE ]");
  39         fprintf(stderr, " [ verbose ]\n");
  40         fprintf(stderr, "\n");
  41         fprintf(stderr, "Where BPF_BYTECODE := \'s,c t f k,c t f k,c t f k,...\'\n");
  42         fprintf(stderr, "c,t,f,k and s are decimals; s denotes number of 4-tuples\n");
  43         fprintf(stderr, "\n");
  44         fprintf(stderr, "Where FILE points to a file containing the BPF_BYTECODE string,\n");
  45         fprintf(stderr, "an ELF file containing eBPF map definitions and bytecode.\n");
  46         fprintf(stderr, "\n");
  47         fprintf(stderr, "Where ACT_NAME refers to the section name containing the\n");
  48         fprintf(stderr, "action (default \'%s\').\n", bpf_default_section(bpf_type));
  49         fprintf(stderr, "\n");
  50         fprintf(stderr, "Where UDS_FILE points to a unix domain socket file in order\n");
  51         fprintf(stderr, "to hand off control of all created eBPF maps to an agent.\n");
  52 }
  53
  54 static void usage(void)
  55 {
  56         explain();
  57         exit(-1);
  58 }
  59
  60 static int parse_bpf(struct action_util *a, int *argc_p, char ***argv_p,
  61                      int tca_id, struct nlmsghdr *n)
  62 {
  63         char **argv = *argv_p, bpf_name[256];
  64         struct rtattr *tail;
  65         struct tc_act_bpf parm = { 0 };
  66         struct sock_filter bpf_ops[BPF_MAXINSNS];
  67         bool ebpf = false, seen_run = false;
  68         const char *bpf_uds_name = NULL;
  69         const char *bpf_sec_name = NULL;
  70         char *bpf_obj = NULL;
  71         int argc = *argc_p, ret = 0;
  72         __u16 bpf_len = 0;
  73         __u32 bpf_fd = 0;
  74
  75         if (matches(*argv, "bpf") != 0)
  76                 return -1;
  77
  78         NEXT_ARG();
  79
  80         while (argc > 0) {
  81                 if (matches(*argv, "run") == 0) {
  82                         bool from_file, bpf_verbose;
  83                         int ret;
  84
  85                         NEXT_ARG();
  86 opt_bpf:
  87                         bpf_sec_name = bpf_default_section(bpf_type);
  88                         bpf_verbose = false;
  89                         seen_run = true;
  90
  91                         if (strcmp(*argv, "bytecode-file") == 0 ||
  92                             strcmp(*argv, "bcf") == 0) {
  93                                 from_file = true;
  94                         } else if (strcmp(*argv, "bytecode") == 0 ||
  95                                    strcmp(*argv, "bc") == 0) {
  96                                 from_file = false;
  97                         } else if (strcmp(*argv, "object-file") == 0 ||
  98                                    strcmp(*argv, "obj") == 0) {
  99                                 ebpf = true;
 100                         } else {
 101                                 fprintf(stderr, "unexpected \"%s\"\n", *argv);
 102                                 explain();
 103                                 return -1;
 104                         }
 105
 106                         NEXT_ARG();
 107                         if (ebpf) {
 108                                 bpf_uds_name = secure_getenv(BPF_ENV_UDS);
 109                                 bpf_obj = *argv;
 110                                 NEXT_ARG();
 111
 112                                 if (strcmp(*argv, "section") == 0 ||
 113                                     strcmp(*argv, "sec") == 0) {
 114                                         NEXT_ARG();
 115                                         bpf_sec_name = *argv;
 116                                         NEXT_ARG();
 117                                 }
 118                                 if (!bpf_uds_name &&
 119                                     (strcmp(*argv, "export") == 0 ||
 120                                      strcmp(*argv, "exp") == 0)) {
 121                                         NEXT_ARG();
 122                                         bpf_uds_name = *argv;
 123                                         NEXT_ARG();
 124                                 }
 125                                 if (strcmp(*argv, "verbose") == 0 ||
 126                                     strcmp(*argv, "verb") == 0) {
 127                                         bpf_verbose = true;
 128                                         NEXT_ARG();
 129                                 }
 130
 131                                 PREV_ARG();
 132                         }
 133
 134                         ret = ebpf ? bpf_open_object(bpf_obj, bpf_type, bpf_sec_name,
 135                                                      bpf_verbose) :
 136                                      bpf_parse_ops(argc, argv, bpf_ops, from_file);
 137                         if (ret < 0) {
 138                                 fprintf(stderr, "%s\n", ebpf ?
 139                                         "Could not load object" :
 140                                         "Illegal \"bytecode\"");
 141                                 return -1;
 142                         }
 143
 144                         if (ebpf) {
 145                                 bpf_obj = basename(bpf_obj);
 146
 147                                 snprintf(bpf_name, sizeof(bpf_name), "%s:[%s]",
 148                                          bpf_obj, bpf_sec_name);
 149
 150                                 bpf_fd = ret;
 151                         } else {
 152                                 bpf_len = ret;
 153                         }
 154                 } else if (matches(*argv, "help") == 0) {
 155                         usage();
 156                 } else {
 157                         if (!seen_run)
 158                                 goto opt_bpf;
 159                         break;
 160                 }
 161                 argc--;
 162                 argv++;
 163         }
 164
 165         parm.action = TC_ACT_PIPE;
 166         if (argc) {
 167                 if (matches(*argv, "reclassify") == 0) {
 168                         parm.action = TC_ACT_RECLASSIFY;
 169                         argc--;
 170                         argv++;
 171                 } else if (matches(*argv, "pipe") == 0) {
 172                         parm.action = TC_ACT_PIPE;
 173                         argc--;
 174                         argv++;
 175                 } else if (matches(*argv, "drop") == 0 ||
 176                            matches(*argv, "shot") == 0) {
 177                         parm.action = TC_ACT_SHOT;
 178                         argc--;
 179                         argv++;
 180                 } else if (matches(*argv, "continue") == 0) {
 181                         parm.action = TC_ACT_UNSPEC;
 182                         argc--;
 183                         argv++;
 184                 } else if (matches(*argv, "pass") == 0) {
 185                         parm.action = TC_ACT_OK;
 186                         argc--;
 187                         argv++;
 188                 }
 189         }
 190
 191         if (argc) {
 192                 if (matches(*argv, "index") == 0) {
 193                         NEXT_ARG();
 194                         if (get_u32(&parm.index, *argv, 10)) {
 195                                 fprintf(stderr, "bpf: Illegal \"index\"\n");
 196                                 return -1;
 197                         }
 198                         argc--;
 199                         argv++;
 200                 }
 201         }
 202
 203         if ((!bpf_len && !ebpf) || (!bpf_fd && ebpf)) {
 204                 fprintf(stderr, "bpf: Bytecode needs to be passed\n");
 205                 explain();
 206                 return -1;
 207         }
 208
 209         tail = NLMSG_TAIL(n);
 210
 211         addattr_l(n, MAX_MSG, tca_id, NULL, 0);
 212         addattr_l(n, MAX_MSG, TCA_ACT_BPF_PARMS, &parm, sizeof(parm));
 213
 214         if (ebpf) {
 215                 addattr32(n, MAX_MSG, TCA_ACT_BPF_FD, bpf_fd);
 216                 addattrstrz(n, MAX_MSG, TCA_ACT_BPF_NAME, bpf_name);
 217         } else {
 218                 addattr16(n, MAX_MSG, TCA_ACT_BPF_OPS_LEN, bpf_len);
 219                 addattr_l(n, MAX_MSG, TCA_ACT_BPF_OPS, &bpf_ops,
 220                           bpf_len * sizeof(struct sock_filter));
 221         }
 222
 223         tail->rta_len = (char *)NLMSG_TAIL(n) - (char *)tail;
 224
 225         *argc_p = argc;
 226         *argv_p = argv;
 227
 228         if (bpf_uds_name)
 229                 ret = bpf_send_map_fds(bpf_uds_name, bpf_obj);
 230
 231         return ret;
 232 }
 233
 234 static int print_bpf(struct action_util *au, FILE *f, struct rtattr *arg)
 235 {
 236         struct rtattr *tb[TCA_ACT_BPF_MAX + 1];
 237         struct tc_act_bpf *parm;
 238         SPRINT_BUF(action_buf);
 239
 240         if (arg == NULL)
 241                 return -1;
 242
 243         parse_rtattr_nested(tb, TCA_ACT_BPF_MAX, arg);
 244
 245         if (!tb[TCA_ACT_BPF_PARMS]) {
 246                 fprintf(f, "[NULL bpf parameters]");
 247                 return -1;
 248         }
 249
 250         parm = RTA_DATA(tb[TCA_ACT_BPF_PARMS]);
 251
 252         fprintf(f, "bpf ");
 253
 254         if (tb[TCA_ACT_BPF_NAME])
 255                 fprintf(f, "%s ", rta_getattr_str(tb[TCA_ACT_BPF_NAME]));
 256         else if (tb[TCA_ACT_BPF_FD])
 257                 fprintf(f, "pfd %u ", rta_getattr_u32(tb[TCA_ACT_BPF_FD]));
 258
 259         if (tb[TCA_ACT_BPF_OPS] && tb[TCA_ACT_BPF_OPS_LEN]) {
 260                 bpf_print_ops(f, tb[TCA_ACT_BPF_OPS],
 261                               rta_getattr_u16(tb[TCA_ACT_BPF_OPS_LEN]));
 262                 fprintf(f, " ");
 263         }
 264
 265         fprintf(f, "default-action %s\n", action_n2a(parm->action, action_buf,
 266                 sizeof(action_buf)));
 267         fprintf(f, "\tindex %d ref %d bind %d", parm->index, parm->refcnt,
 268                 parm->bindcnt);
 269
 270         if (show_stats) {
 271                 if (tb[TCA_ACT_BPF_TM]) {
 272                         struct tcf_t *tm = RTA_DATA(tb[TCA_ACT_BPF_TM]);
 273                         print_tm(f, tm);
 274                 }
 275         }
 276
 277         fprintf(f, "\n ");
 278
 279         return 0;
 280 }
 281
 282 struct action_util bpf_action_util = {
 283         .id = "bpf",
 284         .parse_aopt = parse_bpf,
 285         .print_aopt = print_bpf,
 286 };