tc/f_bpf.c

   1 /*
   2  * f_bpf.c      BPF-based Classifier
   3  *
   4  *              This program is free software; you can distribute 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:     Daniel Borkmann <daniel@iogearbox.net>
  10  */
  11
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14
  15 #include <linux/bpf.h>
  16
  17 #include "utils.h"
  18
  19 #include "tc_util.h"
  20 #include "bpf_util.h"
  21
  22 static const enum bpf_prog_type bpf_type = BPF_PROG_TYPE_SCHED_CLS;
  23
  24 static void explain(void)
  25 {
  26         fprintf(stderr,
  27                 "Usage: ... bpf ...\n"
  28                 "\n"
  29                 "BPF use case:\n"
  30                 " bytecode BPF_BYTECODE\n"
  31                 " bytecode-file FILE\n"
  32                 "\n"
  33                 "eBPF use case:\n"
  34                 " object-file FILE [ section CLS_NAME ] [ export UDS_FILE ]"
  35                 " [ verbose ] [ direct-action ] [ skip_hw | skip_sw ]\n"
  36                 " object-pinned FILE [ direct-action ] [ skip_hw | skip_sw ]\n"
  37                 "\n"
  38                 "Common remaining options:\n"
  39                 " [ action ACTION_SPEC ]\n"
  40                 " [ classid CLASSID ]\n"
  41                 "\n"
  42                 "Where BPF_BYTECODE := \'s,c t f k,c t f k,c t f k,...\'\n"
  43                 "c,t,f,k and s are decimals; s denotes number of 4-tuples\n"
  44                 "\n"
  45                 "Where FILE points to a file containing the BPF_BYTECODE string,\n"
  46                 "an ELF file containing eBPF map definitions and bytecode, or a\n"
  47                 "pinned eBPF program.\n"
  48                 "\n"
  49                 "Where CLS_NAME refers to the section name containing the\n"
  50                 "classifier (default \'%s\').\n"
  51                 "\n"
  52                 "Where UDS_FILE points to a unix domain socket file in order\n"
  53                 "to hand off control of all created eBPF maps to an agent.\n"
  54                 "\n"
  55                 "ACTION_SPEC := ... look at individual actions\n"
  56                 "NOTE: CLASSID is parsed as hexadecimal input.\n",
  57                 bpf_prog_to_default_section(bpf_type));
  58 }
  59
  60 static void bpf_cbpf_cb(void *nl, const struct sock_filter *ops, int ops_len)
  61 {
  62         addattr16(nl, MAX_MSG, TCA_BPF_OPS_LEN, ops_len);
  63         addattr_l(nl, MAX_MSG, TCA_BPF_OPS, ops,
  64                   ops_len * sizeof(struct sock_filter));
  65 }
  66
  67 static void bpf_ebpf_cb(void *nl, int fd, const char *annotation)
  68 {
  69         addattr32(nl, MAX_MSG, TCA_BPF_FD, fd);
  70         addattrstrz(nl, MAX_MSG, TCA_BPF_NAME, annotation);
  71 }
  72
  73 static const struct bpf_cfg_ops bpf_cb_ops = {
  74         .cbpf_cb = bpf_cbpf_cb,
  75         .ebpf_cb = bpf_ebpf_cb,
  76 };
  77
  78 static int bpf_parse_opt(struct filter_util *qu, char *handle,
  79                          int argc, char **argv, struct nlmsghdr *n)
  80 {
  81         const char *bpf_obj = NULL, *bpf_uds_name = NULL;
  82         struct tcmsg *t = NLMSG_DATA(n);
  83         unsigned int bpf_gen_flags = 0;
  84         unsigned int bpf_flags = 0;
  85         struct bpf_cfg_in cfg = {};
  86         bool seen_run = false;
  87         bool skip_sw = false;
  88         struct rtattr *tail;
  89         int ret = 0;
  90
  91         if (handle) {
  92                 if (get_u32(&t->tcm_handle, handle, 0)) {
  93                         fprintf(stderr, "Illegal \"handle\"\n");
  94                         return -1;
  95                 }
  96         }
  97
  98         if (argc == 0)
  99                 return 0;
 100
 101         tail = (struct rtattr *)(((void *)n) + NLMSG_ALIGN(n->nlmsg_len));
 102         addattr_l(n, MAX_MSG, TCA_OPTIONS, NULL, 0);
 103
 104         while (argc > 0) {
 105                 if (matches(*argv, "run") == 0) {
 106                         NEXT_ARG();
 107
 108                         if (seen_run)
 109                                 duparg("run", *argv);
 110 opt_bpf:
 111                         seen_run = true;
 112                         cfg.type = bpf_type;
 113                         cfg.argc = argc;
 114                         cfg.argv = argv;
 115
 116                         if (bpf_parse_common(&cfg, &bpf_cb_ops) < 0) {
 117                                 fprintf(stderr,
 118                                         "Unable to parse bpf command line\n");
 119                                 return -1;
 120                         }
 121
 122                         argc = cfg.argc;
 123                         argv = cfg.argv;
 124
 125                         bpf_obj = cfg.object;
 126                         bpf_uds_name = cfg.uds;
 127                 } else if (matches(*argv, "classid") == 0 ||
 128                            matches(*argv, "flowid") == 0) {
 129                         unsigned int handle;
 130
 131                         NEXT_ARG();
 132                         if (get_tc_classid(&handle, *argv)) {
 133                                 fprintf(stderr, "Illegal \"classid\"\n");
 134                                 return -1;
 135                         }
 136                         addattr32(n, MAX_MSG, TCA_BPF_CLASSID, handle);
 137                 } else if (matches(*argv, "direct-action") == 0 ||
 138                            matches(*argv, "da") == 0) {
 139                         bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
 140                 } else if (matches(*argv, "skip_hw") == 0) {
 141                         bpf_gen_flags |= TCA_CLS_FLAGS_SKIP_HW;
 142                 } else if (matches(*argv, "skip_sw") == 0) {
 143                         bpf_gen_flags |= TCA_CLS_FLAGS_SKIP_SW;
 144                         skip_sw = true;
 145                 } else if (matches(*argv, "action") == 0) {
 146                         NEXT_ARG();
 147                         if (parse_action(&argc, &argv, TCA_BPF_ACT, n)) {
 148                                 fprintf(stderr, "Illegal \"action\"\n");
 149                                 return -1;
 150                         }
 151                         continue;
 152                 } else if (matches(*argv, "police") == 0) {
 153                         NEXT_ARG();
 154                         if (parse_police(&argc, &argv, TCA_BPF_POLICE, n)) {
 155                                 fprintf(stderr, "Illegal \"police\"\n");
 156                                 return -1;
 157                         }
 158                         continue;
 159                 } else if (matches(*argv, "help") == 0) {
 160                         explain();
 161                         return -1;
 162                 } else {
 163                         if (!seen_run)
 164                                 goto opt_bpf;
 165
 166                         fprintf(stderr, "What is \"%s\"?\n", *argv);
 167                         explain();
 168                         return -1;
 169                 }
 170
 171                 NEXT_ARG_FWD();
 172         }
 173
 174         if (skip_sw)
 175                 cfg.ifindex = t->tcm_ifindex;
 176         if (bpf_load_common(&cfg, &bpf_cb_ops, n) < 0) {
 177                 fprintf(stderr, "Unable to load program\n");
 178                 return -1;
 179         }
 180
 181         if (bpf_gen_flags)
 182                 addattr32(n, MAX_MSG, TCA_BPF_FLAGS_GEN, bpf_gen_flags);
 183         if (bpf_flags)
 184                 addattr32(n, MAX_MSG, TCA_BPF_FLAGS, bpf_flags);
 185
 186         tail->rta_len = (((void *)n) + n->nlmsg_len) - (void *)tail;
 187
 188         if (bpf_uds_name)
 189                 ret = bpf_send_map_fds(bpf_uds_name, bpf_obj);
 190
 191         return ret;
 192 }
 193
 194 static int bpf_print_opt(struct filter_util *qu, FILE *f,
 195                          struct rtattr *opt, __u32 handle)
 196 {
 197         struct rtattr *tb[TCA_BPF_MAX + 1];
 198         int dump_ok = 0;
 199
 200         if (opt == NULL)
 201                 return 0;
 202
 203         parse_rtattr_nested(tb, TCA_BPF_MAX, opt);
 204
 205         if (handle)
 206                 fprintf(f, "handle 0x%x ", handle);
 207
 208         if (tb[TCA_BPF_CLASSID]) {
 209                 SPRINT_BUF(b1);
 210                 fprintf(f, "flowid %s ",
 211                         sprint_tc_classid(rta_getattr_u32(tb[TCA_BPF_CLASSID]), b1));
 212         }
 213
 214         if (tb[TCA_BPF_NAME])
 215                 fprintf(f, "%s ", rta_getattr_str(tb[TCA_BPF_NAME]));
 216
 217         if (tb[TCA_BPF_FLAGS]) {
 218                 unsigned int flags = rta_getattr_u32(tb[TCA_BPF_FLAGS]);
 219
 220                 if (flags & TCA_BPF_FLAG_ACT_DIRECT)
 221                         fprintf(f, "direct-action ");
 222         }
 223
 224         if (tb[TCA_BPF_FLAGS_GEN]) {
 225                 unsigned int flags =
 226                         rta_getattr_u32(tb[TCA_BPF_FLAGS_GEN]);
 227
 228                 if (flags & TCA_CLS_FLAGS_SKIP_HW)
 229                         fprintf(f, "skip_hw ");
 230                 if (flags & TCA_CLS_FLAGS_SKIP_SW)
 231                         fprintf(f, "skip_sw ");
 232
 233                 if (flags & TCA_CLS_FLAGS_IN_HW)
 234                         fprintf(f, "in_hw ");
 235                 else if (flags & TCA_CLS_FLAGS_NOT_IN_HW)
 236                         fprintf(f, "not_in_hw ");
 237         }
 238
 239         if (tb[TCA_BPF_OPS] && tb[TCA_BPF_OPS_LEN])
 240                 bpf_print_ops(tb[TCA_BPF_OPS],
 241                               rta_getattr_u16(tb[TCA_BPF_OPS_LEN]));
 242
 243         if (tb[TCA_BPF_ID])
 244                 dump_ok = bpf_dump_prog_info(f, rta_getattr_u32(tb[TCA_BPF_ID]));
 245         if (!dump_ok && tb[TCA_BPF_TAG]) {
 246                 SPRINT_BUF(b);
 247
 248                 fprintf(f, "tag %s ",
 249                         hexstring_n2a(RTA_DATA(tb[TCA_BPF_TAG]),
 250                                       RTA_PAYLOAD(tb[TCA_BPF_TAG]),
 251                                       b, sizeof(b)));
 252         }
 253
 254         if (tb[TCA_BPF_POLICE]) {
 255                 fprintf(f, "\n");
 256                 tc_print_police(f, tb[TCA_BPF_POLICE]);
 257         }
 258
 259         if (tb[TCA_BPF_ACT])
 260                 tc_print_action(f, tb[TCA_BPF_ACT], 0);
 261
 262         return 0;
 263 }
 264
 265 struct filter_util bpf_filter_util = {
 266         .id             = "bpf",
 267         .parse_fopt     = bpf_parse_opt,
 268         .print_fopt     = bpf_print_opt,
 269 };