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