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 ... [ index INDEX ]\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         fprintf(stderr, "\n");
  53         fprintf(stderr, "Where optionally INDEX points to an existing action, or\n");
  54         fprintf(stderr, "explicitly specifies an action index upon creation.\n");
  55 }
  56
  57 static void usage(void)
  58 {
  59         explain();
  60         exit(-1);
  61 }
  62
  63 static int parse_bpf(struct action_util *a, int *argc_p, char ***argv_p,
  64                      int tca_id, struct nlmsghdr *n)
  65 {
  66         char **argv = *argv_p, bpf_name[256];
  67         struct rtattr *tail;
  68         struct tc_act_bpf parm = { 0 };
  69         struct sock_filter bpf_ops[BPF_MAXINSNS];
  70         bool ebpf_fill = false, bpf_fill = false;
  71         bool ebpf = false, seen_run = false;
  72         const char *bpf_uds_name = NULL;
  73         const char *bpf_sec_name = NULL;
  74         char *bpf_obj = NULL;
  75         int argc = *argc_p, ret = 0;
  76         __u16 bpf_len = 0;
  77         __u32 bpf_fd = 0;
  78
  79         if (matches(*argv, "bpf") != 0)
  80                 return -1;
  81
  82         NEXT_ARG();
  83
  84         while (argc > 0) {
  85                 if (matches(*argv, "run") == 0) {
  86                         bool from_file, bpf_verbose;
  87                         int ret;
  88
  89                         NEXT_ARG();
  90 opt_bpf:
  91                         bpf_sec_name = bpf_default_section(bpf_type);
  92                         bpf_verbose = false;
  93                         seen_run = true;
  94
  95                         if (strcmp(*argv, "bytecode-file") == 0 ||
  96                             strcmp(*argv, "bcf") == 0) {
  97                                 from_file = true;
  98                         } else if (strcmp(*argv, "bytecode") == 0 ||
  99                                    strcmp(*argv, "bc") == 0) {
 100                                 from_file = false;
 101                         } else if (strcmp(*argv, "object-file") == 0 ||
 102                                    strcmp(*argv, "obj") == 0) {
 103                                 ebpf = true;
 104                         } else {
 105                                 fprintf(stderr, "unexpected \"%s\"\n", *argv);
 106                                 explain();
 107                                 return -1;
 108                         }
 109
 110                         NEXT_ARG();
 111                         if (ebpf) {
 112                                 bpf_uds_name = getenv(BPF_ENV_UDS);
 113                                 bpf_obj = *argv;
 114
 115                                 NEXT_ARG_FWD();
 116
 117                                 if (argc > 0 &&
 118                                     (strcmp(*argv, "section") == 0 ||
 119                                      strcmp(*argv, "sec") == 0)) {
 120                                         NEXT_ARG();
 121                                         bpf_sec_name = *argv;
 122                                         NEXT_ARG_FWD();
 123                                 }
 124                                 if (argc > 0 && !bpf_uds_name &&
 125                                     (strcmp(*argv, "export") == 0 ||
 126                                      strcmp(*argv, "exp") == 0)) {
 127                                         NEXT_ARG();
 128                                         bpf_uds_name = *argv;
 129                                         NEXT_ARG_FWD();
 130                                 }
 131                                 if (argc > 0 &&
 132                                     (strcmp(*argv, "verbose") == 0 ||
 133                                      strcmp(*argv, "verb") == 0)) {
 134                                         bpf_verbose = true;
 135                                         NEXT_ARG_FWD();
 136                                 }
 137
 138                                 PREV_ARG();
 139                         }
 140
 141                         ret = ebpf ? bpf_open_object(bpf_obj, bpf_type, bpf_sec_name,
 142                                                      bpf_verbose) :
 143                                      bpf_parse_ops(argc, argv, bpf_ops, from_file);
 144                         if (ret < 0) {
 145                                 fprintf(stderr, "%s\n", ebpf ?
 146                                         "Could not load object" :
 147                                         "Illegal \"bytecode\"");
 148                                 return -1;
 149                         }
 150
 151                         if (ebpf) {
 152                                 bpf_obj = basename(bpf_obj);
 153
 154                                 snprintf(bpf_name, sizeof(bpf_name), "%s:[%s]",
 155                                          bpf_obj, bpf_sec_name);
 156
 157                                 bpf_fd = ret;
 158                                 ebpf_fill = true;
 159                         } else {
 160                                 bpf_len = ret;
 161                                 bpf_fill = true;
 162                         }
 163                 } else if (matches(*argv, "help") == 0) {
 164                         usage();
 165                 } else if (matches(*argv, "index") == 0) {
 166                         break;
 167                 } else {
 168                         if (!seen_run)
 169                                 goto opt_bpf;
 170                         break;
 171                 }
 172
 173                 NEXT_ARG_FWD();
 174         }
 175
 176         parm.action = TC_ACT_PIPE;
 177         if (argc) {
 178                 if (matches(*argv, "reclassify") == 0) {
 179                         parm.action = TC_ACT_RECLASSIFY;
 180                         NEXT_ARG_FWD();
 181                 } else if (matches(*argv, "pipe") == 0) {
 182                         parm.action = TC_ACT_PIPE;
 183                         NEXT_ARG_FWD();
 184                 } else if (matches(*argv, "drop") == 0 ||
 185                            matches(*argv, "shot") == 0) {
 186                         parm.action = TC_ACT_SHOT;
 187                         NEXT_ARG_FWD();
 188                 } else if (matches(*argv, "continue") == 0) {
 189                         parm.action = TC_ACT_UNSPEC;
 190                         NEXT_ARG_FWD();
 191                 } else if (matches(*argv, "pass") == 0 ||
 192                            matches(*argv, "ok") == 0) {
 193                         parm.action = TC_ACT_OK;
 194                         NEXT_ARG_FWD();
 195                 }
 196         }
 197
 198         if (argc) {
 199                 if (matches(*argv, "index") == 0) {
 200                         NEXT_ARG();
 201                         if (get_u32(&parm.index, *argv, 10)) {
 202                                 fprintf(stderr, "bpf: Illegal \"index\"\n");
 203                                 return -1;
 204                         }
 205
 206                         NEXT_ARG_FWD();
 207                 }
 208         }
 209
 210         tail = NLMSG_TAIL(n);
 211
 212         addattr_l(n, MAX_MSG, tca_id, NULL, 0);
 213         addattr_l(n, MAX_MSG, TCA_ACT_BPF_PARMS, &parm, sizeof(parm));
 214
 215         if (ebpf_fill) {
 216                 addattr32(n, MAX_MSG, TCA_ACT_BPF_FD, bpf_fd);
 217                 addattrstrz(n, MAX_MSG, TCA_ACT_BPF_NAME, bpf_name);
 218         } else if (bpf_fill) {
 219                 addattr16(n, MAX_MSG, TCA_ACT_BPF_OPS_LEN, bpf_len);
 220                 addattr_l(n, MAX_MSG, TCA_ACT_BPF_OPS, &bpf_ops,
 221                           bpf_len * sizeof(struct sock_filter));
 222         }
 223
 224         tail->rta_len = (char *)NLMSG_TAIL(n) - (char *)tail;
 225
 226         *argc_p = argc;
 227         *argv_p = argv;
 228
 229         if (bpf_uds_name)
 230                 ret = bpf_send_map_fds(bpf_uds_name, bpf_obj);
 231
 232         return ret;
 233 }
 234
 235 static int print_bpf(struct action_util *au, FILE *f, struct rtattr *arg)
 236 {
 237         struct rtattr *tb[TCA_ACT_BPF_MAX + 1];
 238         struct tc_act_bpf *parm;
 239         SPRINT_BUF(action_buf);
 240
 241         if (arg == NULL)
 242                 return -1;
 243
 244         parse_rtattr_nested(tb, TCA_ACT_BPF_MAX, arg);
 245
 246         if (!tb[TCA_ACT_BPF_PARMS]) {
 247                 fprintf(f, "[NULL bpf parameters]");
 248                 return -1;
 249         }
 250
 251         parm = RTA_DATA(tb[TCA_ACT_BPF_PARMS]);
 252
 253         fprintf(f, "bpf ");
 254
 255         if (tb[TCA_ACT_BPF_NAME])
 256                 fprintf(f, "%s ", rta_getattr_str(tb[TCA_ACT_BPF_NAME]));
 257         else if (tb[TCA_ACT_BPF_FD])
 258                 fprintf(f, "pfd %u ", rta_getattr_u32(tb[TCA_ACT_BPF_FD]));
 259
 260         if (tb[TCA_ACT_BPF_OPS] && tb[TCA_ACT_BPF_OPS_LEN]) {
 261                 bpf_print_ops(f, tb[TCA_ACT_BPF_OPS],
 262                               rta_getattr_u16(tb[TCA_ACT_BPF_OPS_LEN]));
 263                 fprintf(f, " ");
 264         }
 265
 266         fprintf(f, "default-action %s\n", action_n2a(parm->action, action_buf,
 267                 sizeof(action_buf)));
 268         fprintf(f, "\tindex %d ref %d bind %d", parm->index, parm->refcnt,
 269                 parm->bindcnt);
 270
 271         if (show_stats) {
 272                 if (tb[TCA_ACT_BPF_TM]) {
 273                         struct tcf_t *tm = RTA_DATA(tb[TCA_ACT_BPF_TM]);
 274                         print_tm(f, tm);
 275                 }
 276         }
 277
 278         fprintf(f, "\n ");
 279
 280         return 0;
 281 }
 282
 283 struct action_util bpf_action_util = {
 284         .id = "bpf",
 285         .parse_aopt = parse_bpf,
 286         .print_aopt = print_bpf,
 287 };