tc/m_bpf.c

   1 /*
   2  * m_bpf.c      BFP 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 ]\n");
  39         fprintf(stderr, "\n");
  40         fprintf(stderr, "Where BPF_BYTECODE := \'s,c t f k,c t f k,c t f k,...\'\n");
  41         fprintf(stderr, "c,t,f,k and s are decimals; s denotes number of 4-tuples\n");
  42         fprintf(stderr, "\n");
  43         fprintf(stderr, "Where FILE points to a file containing the BPF_BYTECODE string,\n");
  44         fprintf(stderr, "an ELF file containing eBPF map definitions and bytecode.\n");
  45         fprintf(stderr, "\n");
  46         fprintf(stderr, "Where ACT_NAME refers to the section name containing the\n");
  47         fprintf(stderr, "action (default \'%s\').\n", bpf_default_section(bpf_type));
  48         fprintf(stderr, "\n");
  49         fprintf(stderr, "Where UDS_FILE points to a unix domain socket file in order\n");
  50         fprintf(stderr, "to hand off control of all created eBPF maps to an agent.\n");
  51 }
  52
  53 static void usage(void)
  54 {
  55         explain();
  56         exit(-1);
  57 }
  58
  59 static int parse_bpf(struct action_util *a, int *argc_p, char ***argv_p,
  60                      int tca_id, struct nlmsghdr *n)
  61 {
  62         char **argv = *argv_p, bpf_name[256];
  63         struct rtattr *tail;
  64         struct tc_act_bpf parm = { 0 };
  65         struct sock_filter bpf_ops[BPF_MAXINSNS];
  66         bool ebpf = false, seen_run = false;
  67         const char *bpf_uds_name = NULL;
  68         const char *bpf_sec_name = NULL;
  69         char *bpf_obj = NULL;
  70         int argc = *argc_p, ret = 0;
  71         __u16 bpf_len = 0;
  72         __u32 bpf_fd = 0;
  73
  74         if (matches(*argv, "bpf") != 0)
  75                 return -1;
  76
  77         NEXT_ARG();
  78
  79         while (argc > 0) {
  80                 if (matches(*argv, "run") == 0) {
  81                         bool from_file;
  82                         int ret;
  83
  84                         NEXT_ARG();
  85 opt_bpf:
  86                         bpf_sec_name = bpf_default_section(bpf_type);
  87                         seen_run = true;
  88
  89                         if (strcmp(*argv, "bytecode-file") == 0 ||
  90                             strcmp(*argv, "bcf") == 0) {
  91                                 from_file = true;
  92                         } else if (strcmp(*argv, "bytecode") == 0 ||
  93                                    strcmp(*argv, "bc") == 0) {
  94                                 from_file = false;
  95                         } else if (strcmp(*argv, "object-file") == 0 ||
  96                                    strcmp(*argv, "obj") == 0) {
  97                                 ebpf = true;
  98                         } else {
  99                                 fprintf(stderr, "unexpected \"%s\"\n", *argv);
 100                                 explain();
 101                                 return -1;
 102                         }
 103
 104                         NEXT_ARG();
 105                         if (ebpf) {
 106                                 bpf_obj = *argv;
 107                                 NEXT_ARG();
 108
 109                                 if (strcmp(*argv, "section") == 0 ||
 110                                     strcmp(*argv, "sec") == 0) {
 111                                         NEXT_ARG();
 112                                         bpf_sec_name = *argv;
 113                                         NEXT_ARG();
 114                                 }
 115                                 if (strcmp(*argv, "export") == 0 ||
 116                                     strcmp(*argv, "exp") == 0) {
 117                                         NEXT_ARG();
 118                                         bpf_uds_name = *argv;
 119                                         NEXT_ARG();
 120                                 }
 121
 122                                 PREV_ARG();
 123                         }
 124
 125                         ret = ebpf ? bpf_open_object(bpf_obj, bpf_type, bpf_sec_name) :
 126                                      bpf_parse_ops(argc, argv, bpf_ops, from_file);
 127                         if (ret < 0) {
 128                                 fprintf(stderr, "%s\n", ebpf ?
 129                                         "Could not load object" :
 130                                         "Illegal \"bytecode\"");
 131                                 return -1;
 132                         }
 133
 134                         if (ebpf) {
 135                                 bpf_obj = basename(bpf_obj);
 136
 137                                 snprintf(bpf_name, sizeof(bpf_name), "%s:[%s]",
 138                                          bpf_obj, bpf_sec_name);
 139
 140                                 bpf_fd = ret;
 141                         } else {
 142                                 bpf_len = ret;
 143                         }
 144                 } else if (matches(*argv, "help") == 0) {
 145                         usage();
 146                 } else {
 147                         if (!seen_run)
 148                                 goto opt_bpf;
 149                         break;
 150                 }
 151                 argc--;
 152                 argv++;
 153         }
 154
 155         parm.action = TC_ACT_PIPE;
 156         if (argc) {
 157                 if (matches(*argv, "reclassify") == 0) {
 158                         parm.action = TC_ACT_RECLASSIFY;
 159                         argc--;
 160                         argv++;
 161                 } else if (matches(*argv, "pipe") == 0) {
 162                         parm.action = TC_ACT_PIPE;
 163                         argc--;
 164                         argv++;
 165                 } else if (matches(*argv, "drop") == 0 ||
 166                            matches(*argv, "shot") == 0) {
 167                         parm.action = TC_ACT_SHOT;
 168                         argc--;
 169                         argv++;
 170                 } else if (matches(*argv, "continue") == 0) {
 171                         parm.action = TC_ACT_UNSPEC;
 172                         argc--;
 173                         argv++;
 174                 } else if (matches(*argv, "pass") == 0) {
 175                         parm.action = TC_ACT_OK;
 176                         argc--;
 177                         argv++;
 178                 }
 179         }
 180
 181         if (argc) {
 182                 if (matches(*argv, "index") == 0) {
 183                         NEXT_ARG();
 184                         if (get_u32(&parm.index, *argv, 10)) {
 185                                 fprintf(stderr, "bpf: Illegal \"index\"\n");
 186                                 return -1;
 187                         }
 188                         argc--;
 189                         argv++;
 190                 }
 191         }
 192
 193         if ((!bpf_len && !ebpf) || (!bpf_fd && ebpf)) {
 194                 fprintf(stderr, "bpf: Bytecode needs to be passed\n");
 195                 explain();
 196                 return -1;
 197         }
 198
 199         tail = NLMSG_TAIL(n);
 200
 201         addattr_l(n, MAX_MSG, tca_id, NULL, 0);
 202         addattr_l(n, MAX_MSG, TCA_ACT_BPF_PARMS, &parm, sizeof(parm));
 203
 204         if (ebpf) {
 205                 addattr32(n, MAX_MSG, TCA_ACT_BPF_FD, bpf_fd);
 206                 addattrstrz(n, MAX_MSG, TCA_ACT_BPF_NAME, bpf_name);
 207         } else {
 208                 addattr16(n, MAX_MSG, TCA_ACT_BPF_OPS_LEN, bpf_len);
 209                 addattr_l(n, MAX_MSG, TCA_ACT_BPF_OPS, &bpf_ops,
 210                           bpf_len * sizeof(struct sock_filter));
 211         }
 212
 213         tail->rta_len = (char *)NLMSG_TAIL(n) - (char *)tail;
 214
 215         *argc_p = argc;
 216         *argv_p = argv;
 217
 218         if (bpf_uds_name)
 219                 ret = bpf_send_map_fds(bpf_uds_name, bpf_obj);
 220
 221         return ret;
 222 }
 223
 224 static int print_bpf(struct action_util *au, FILE *f, struct rtattr *arg)
 225 {
 226         struct rtattr *tb[TCA_ACT_BPF_MAX + 1];
 227         struct tc_act_bpf *parm;
 228         SPRINT_BUF(action_buf);
 229
 230         if (arg == NULL)
 231                 return -1;
 232
 233         parse_rtattr_nested(tb, TCA_ACT_BPF_MAX, arg);
 234
 235         if (!tb[TCA_ACT_BPF_PARMS]) {
 236                 fprintf(f, "[NULL bpf parameters]");
 237                 return -1;
 238         }
 239
 240         parm = RTA_DATA(tb[TCA_ACT_BPF_PARMS]);
 241
 242         fprintf(f, "bpf ");
 243
 244         if (tb[TCA_ACT_BPF_NAME])
 245                 fprintf(f, "%s ", rta_getattr_str(tb[TCA_ACT_BPF_NAME]));
 246         else if (tb[TCA_ACT_BPF_FD])
 247                 fprintf(f, "pfd %u ", rta_getattr_u32(tb[TCA_ACT_BPF_FD]));
 248
 249         if (tb[TCA_ACT_BPF_OPS] && tb[TCA_ACT_BPF_OPS_LEN]) {
 250                 bpf_print_ops(f, tb[TCA_ACT_BPF_OPS],
 251                               rta_getattr_u16(tb[TCA_ACT_BPF_OPS_LEN]));
 252                 fprintf(f, " ");
 253         }
 254
 255         fprintf(f, "default-action %s\n", action_n2a(parm->action, action_buf,
 256                 sizeof(action_buf)));
 257         fprintf(f, "\tindex %d ref %d bind %d", parm->index, parm->refcnt,
 258                 parm->bindcnt);
 259
 260         if (show_stats) {
 261                 if (tb[TCA_ACT_BPF_TM]) {
 262                         struct tcf_t *tm = RTA_DATA(tb[TCA_ACT_BPF_TM]);
 263                         print_tm(f, tm);
 264                 }
 265         }
 266
 267         fprintf(f, "\n ");
 268
 269         return 0;
 270 }
 271
 272 struct action_util bpf_action_util = {
 273         .id = "bpf",
 274         .parse_aopt = parse_bpf,
 275         .print_aopt = print_bpf,
 276 };