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         struct rtattr *tail;
  86         int ret = 0;
  87
  88         if (handle) {
  89                 if (get_u32(&t->tcm_handle, handle, 0)) {
  90                         fprintf(stderr, "Illegal \"handle\"\n");
  91                         return -1;
  92                 }
  93         }
  94
  95         if (argc == 0)
  96                 return 0;
  97
  98         tail = (struct rtattr *)(((void *)n) + NLMSG_ALIGN(n->nlmsg_len));
  99         addattr_l(n, MAX_MSG, TCA_OPTIONS, NULL, 0);
 100
 101         while (argc > 0) {
 102                 if (matches(*argv, "run") == 0) {
 103                         NEXT_ARG();
 104 opt_bpf:
 105                         seen_run = true;
 106                         cfg.argc = argc;
 107                         cfg.argv = argv;
 108
 109                         if (bpf_parse_common(bpf_type, &cfg, &bpf_cb_ops, n))
 110                                 return -1;
 111
 112                         argc = cfg.argc;
 113                         argv = cfg.argv;
 114
 115                         bpf_obj = cfg.object;
 116                         bpf_uds_name = cfg.uds;
 117                 } else if (matches(*argv, "classid") == 0 ||
 118                            matches(*argv, "flowid") == 0) {
 119                         unsigned int handle;
 120
 121                         NEXT_ARG();
 122                         if (get_tc_classid(&handle, *argv)) {
 123                                 fprintf(stderr, "Illegal \"classid\"\n");
 124                                 return -1;
 125                         }
 126                         addattr32(n, MAX_MSG, TCA_BPF_CLASSID, handle);
 127                 } else if (matches(*argv, "direct-action") == 0 ||
 128                            matches(*argv, "da") == 0) {
 129                         bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
 130                 } else if (matches(*argv, "skip_hw") == 0) {
 131                         bpf_gen_flags |= TCA_CLS_FLAGS_SKIP_HW;
 132                 } else if (matches(*argv, "skip_sw") == 0) {
 133                         bpf_gen_flags |= TCA_CLS_FLAGS_SKIP_SW;
 134                 } else if (matches(*argv, "action") == 0) {
 135                         NEXT_ARG();
 136                         if (parse_action(&argc, &argv, TCA_BPF_ACT, n)) {
 137                                 fprintf(stderr, "Illegal \"action\"\n");
 138                                 return -1;
 139                         }
 140                         continue;
 141                 } else if (matches(*argv, "police") == 0) {
 142                         NEXT_ARG();
 143                         if (parse_police(&argc, &argv, TCA_BPF_POLICE, n)) {
 144                                 fprintf(stderr, "Illegal \"police\"\n");
 145                                 return -1;
 146                         }
 147                         continue;
 148                 } else if (matches(*argv, "help") == 0) {
 149                         explain();
 150                         return -1;
 151                 } else {
 152                         if (!seen_run)
 153                                 goto opt_bpf;
 154
 155                         fprintf(stderr, "What is \"%s\"?\n", *argv);
 156                         explain();
 157                         return -1;
 158                 }
 159
 160                 NEXT_ARG_FWD();
 161         }
 162
 163         if (bpf_gen_flags)
 164                 addattr32(n, MAX_MSG, TCA_BPF_FLAGS_GEN, bpf_gen_flags);
 165         if (bpf_flags)
 166                 addattr32(n, MAX_MSG, TCA_BPF_FLAGS, bpf_flags);
 167
 168         tail->rta_len = (((void *)n) + n->nlmsg_len) - (void *)tail;
 169
 170         if (bpf_uds_name)
 171                 ret = bpf_send_map_fds(bpf_uds_name, bpf_obj);
 172
 173         return ret;
 174 }
 175
 176 static int bpf_print_opt(struct filter_util *qu, FILE *f,
 177                          struct rtattr *opt, __u32 handle)
 178 {
 179         struct rtattr *tb[TCA_BPF_MAX + 1];
 180
 181         if (opt == NULL)
 182                 return 0;
 183
 184         parse_rtattr_nested(tb, TCA_BPF_MAX, opt);
 185
 186         if (handle)
 187                 fprintf(f, "handle 0x%x ", handle);
 188
 189         if (tb[TCA_BPF_CLASSID]) {
 190                 SPRINT_BUF(b1);
 191                 fprintf(f, "flowid %s ",
 192                         sprint_tc_classid(rta_getattr_u32(tb[TCA_BPF_CLASSID]), b1));
 193         }
 194
 195         if (tb[TCA_BPF_NAME])
 196                 fprintf(f, "%s ", rta_getattr_str(tb[TCA_BPF_NAME]));
 197
 198         if (tb[TCA_BPF_FLAGS]) {
 199                 unsigned int flags = rta_getattr_u32(tb[TCA_BPF_FLAGS]);
 200
 201                 if (flags & TCA_BPF_FLAG_ACT_DIRECT)
 202                         fprintf(f, "direct-action ");
 203         }
 204
 205         if (tb[TCA_BPF_FLAGS_GEN]) {
 206                 unsigned int flags =
 207                         rta_getattr_u32(tb[TCA_BPF_FLAGS_GEN]);
 208
 209                 if (flags & TCA_CLS_FLAGS_SKIP_HW)
 210                         fprintf(f, "skip_hw ");
 211                 if (flags & TCA_CLS_FLAGS_SKIP_SW)
 212                         fprintf(f, "skip_sw ");
 213         }
 214
 215         if (tb[TCA_BPF_OPS] && tb[TCA_BPF_OPS_LEN])
 216                 bpf_print_ops(f, tb[TCA_BPF_OPS],
 217                               rta_getattr_u16(tb[TCA_BPF_OPS_LEN]));
 218
 219         if (tb[TCA_BPF_POLICE]) {
 220                 fprintf(f, "\n");
 221                 tc_print_police(f, tb[TCA_BPF_POLICE]);
 222         }
 223
 224         if (tb[TCA_BPF_ACT])
 225                 tc_print_action(f, tb[TCA_BPF_ACT]);
 226
 227         return 0;
 228 }
 229
 230 struct filter_util bpf_filter_util = {
 231         .id             = "bpf",
 232         .parse_fopt     = bpf_parse_opt,
 233         .print_fopt     = bpf_print_opt,
 234 };