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                                 NEXT_ARG();
 115
 116                                 if (strcmp(*argv, "section") == 0 ||
 117                                     strcmp(*argv, "sec") == 0) {
 118                                         NEXT_ARG();
 119                                         bpf_sec_name = *argv;
 120                                         NEXT_ARG();
 121                                 }
 122                                 if (!bpf_uds_name &&
 123                                     (strcmp(*argv, "export") == 0 ||
 124                                      strcmp(*argv, "exp") == 0)) {
 125                                         NEXT_ARG();
 126                                         bpf_uds_name = *argv;
 127                                         NEXT_ARG();
 128                                 }
 129                                 if (strcmp(*argv, "verbose") == 0 ||
 130                                     strcmp(*argv, "verb") == 0) {
 131                                         bpf_verbose = true;
 132                                         NEXT_ARG();
 133                                 }
 134
 135                                 PREV_ARG();
 136                         }
 137
 138                         ret = ebpf ? bpf_open_object(bpf_obj, bpf_type, bpf_sec_name,
 139                                                      bpf_verbose) :
 140                                      bpf_parse_ops(argc, argv, bpf_ops, from_file);
 141                         if (ret < 0) {
 142                                 fprintf(stderr, "%s\n", ebpf ?
 143                                         "Could not load object" :
 144                                         "Illegal \"bytecode\"");
 145                                 return -1;
 146                         }
 147
 148                         if (ebpf) {
 149                                 bpf_obj = basename(bpf_obj);
 150
 151                                 snprintf(bpf_name, sizeof(bpf_name), "%s:[%s]",
 152                                          bpf_obj, bpf_sec_name);
 153
 154                                 bpf_fd = ret;
 155                                 ebpf_fill = true;
 156                         } else {
 157                                 bpf_len = ret;
 158                                 bpf_fill = true;
 159                         }
 160                 } else if (matches(*argv, "help") == 0) {
 161                         usage();
 162                 } else if (matches(*argv, "index") == 0) {
 163                         break;
 164                 } else {
 165                         if (!seen_run)
 166                                 goto opt_bpf;
 167                         break;
 168                 }
 169                 argc--;
 170                 argv++;
 171         }
 172
 173         parm.action = TC_ACT_PIPE;
 174         if (argc) {
 175                 if (matches(*argv, "reclassify") == 0) {
 176                         parm.action = TC_ACT_RECLASSIFY;
 177                         argc--;
 178                         argv++;
 179                 } else if (matches(*argv, "pipe") == 0) {
 180                         parm.action = TC_ACT_PIPE;
 181                         argc--;
 182                         argv++;
 183                 } else if (matches(*argv, "drop") == 0 ||
 184                            matches(*argv, "shot") == 0) {
 185                         parm.action = TC_ACT_SHOT;
 186                         argc--;
 187                         argv++;
 188                 } else if (matches(*argv, "continue") == 0) {
 189                         parm.action = TC_ACT_UNSPEC;
 190                         argc--;
 191                         argv++;
 192                 } else if (matches(*argv, "pass") == 0) {
 193                         parm.action = TC_ACT_OK;
 194                         argc--;
 195                         argv++;
 196                 }
 197         }
 198
 199         if (argc) {
 200                 if (matches(*argv, "index") == 0) {
 201                         NEXT_ARG();
 202                         if (get_u32(&parm.index, *argv, 10)) {
 203                                 fprintf(stderr, "bpf: Illegal \"index\"\n");
 204                                 return -1;
 205                         }
 206                         argc--;
 207                         argv++;
 208                 }
 209         }
 210
 211         tail = NLMSG_TAIL(n);
 212
 213         addattr_l(n, MAX_MSG, tca_id, NULL, 0);
 214         addattr_l(n, MAX_MSG, TCA_ACT_BPF_PARMS, &parm, sizeof(parm));
 215
 216         if (ebpf_fill) {
 217                 addattr32(n, MAX_MSG, TCA_ACT_BPF_FD, bpf_fd);
 218                 addattrstrz(n, MAX_MSG, TCA_ACT_BPF_NAME, bpf_name);
 219         } else if (bpf_fill) {
 220                 addattr16(n, MAX_MSG, TCA_ACT_BPF_OPS_LEN, bpf_len);
 221                 addattr_l(n, MAX_MSG, TCA_ACT_BPF_OPS, &bpf_ops,
 222                           bpf_len * sizeof(struct sock_filter));
 223         }
 224
 225         tail->rta_len = (char *)NLMSG_TAIL(n) - (char *)tail;
 226
 227         *argc_p = argc;
 228         *argv_p = argv;
 229
 230         if (bpf_uds_name)
 231                 ret = bpf_send_map_fds(bpf_uds_name, bpf_obj);
 232
 233         return ret;
 234 }
 235
 236 static int print_bpf(struct action_util *au, FILE *f, struct rtattr *arg)
 237 {
 238         struct rtattr *tb[TCA_ACT_BPF_MAX + 1];
 239         struct tc_act_bpf *parm;
 240         SPRINT_BUF(action_buf);
 241
 242         if (arg == NULL)
 243                 return -1;
 244
 245         parse_rtattr_nested(tb, TCA_ACT_BPF_MAX, arg);
 246
 247         if (!tb[TCA_ACT_BPF_PARMS]) {
 248                 fprintf(f, "[NULL bpf parameters]");
 249                 return -1;
 250         }
 251
 252         parm = RTA_DATA(tb[TCA_ACT_BPF_PARMS]);
 253
 254         fprintf(f, "bpf ");
 255
 256         if (tb[TCA_ACT_BPF_NAME])
 257                 fprintf(f, "%s ", rta_getattr_str(tb[TCA_ACT_BPF_NAME]));
 258         else if (tb[TCA_ACT_BPF_FD])
 259                 fprintf(f, "pfd %u ", rta_getattr_u32(tb[TCA_ACT_BPF_FD]));
 260
 261         if (tb[TCA_ACT_BPF_OPS] && tb[TCA_ACT_BPF_OPS_LEN]) {
 262                 bpf_print_ops(f, tb[TCA_ACT_BPF_OPS],
 263                               rta_getattr_u16(tb[TCA_ACT_BPF_OPS_LEN]));
 264                 fprintf(f, " ");
 265         }
 266
 267         fprintf(f, "default-action %s\n", action_n2a(parm->action, action_buf,
 268                 sizeof(action_buf)));
 269         fprintf(f, "\tindex %d ref %d bind %d", parm->index, parm->refcnt,
 270                 parm->bindcnt);
 271
 272         if (show_stats) {
 273                 if (tb[TCA_ACT_BPF_TM]) {
 274                         struct tcf_t *tm = RTA_DATA(tb[TCA_ACT_BPF_TM]);
 275                         print_tm(f, tm);
 276                 }
 277         }
 278
 279         fprintf(f, "\n ");
 280
 281         return 0;
 282 }
 283
 284 struct action_util bpf_action_util = {
 285         .id = "bpf",
 286         .parse_aopt = parse_bpf,
 287         .print_aopt = print_bpf,
 288 };