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 <dborkman@redhat.com>
  10  */
  11
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <unistd.h>
  15 #include <syslog.h>
  16 #include <fcntl.h>
  17 #include <libgen.h>
  18 #include <sys/socket.h>
  19 #include <netinet/in.h>
  20 #include <arpa/inet.h>
  21 #include <string.h>
  22 #include <stdbool.h>
  23 #include <errno.h>
  24 #include <limits.h>
  25 #include <linux/filter.h>
  26 #include <linux/if.h>
  27
  28 #include "utils.h"
  29 #include "tc_util.h"
  30 #include "tc_bpf.h"
  31
  32 static const enum bpf_prog_type bpf_type = BPF_PROG_TYPE_SCHED_CLS;
  33
  34 static void explain(void)
  35 {
  36         fprintf(stderr, "Usage: ... bpf ...\n");
  37         fprintf(stderr, "\n");
  38         fprintf(stderr, "BPF use case:\n");
  39         fprintf(stderr, " bytecode BPF_BYTECODE\n");
  40         fprintf(stderr, " bytecode-file FILE\n");
  41         fprintf(stderr, "\n");
  42         fprintf(stderr, "eBPF use case:\n");
  43         fprintf(stderr, " object-file FILE [ section CLS_NAME ] [ export UDS_FILE ]");
  44         fprintf(stderr, " [ verbose ] [ direct-action ]\n");
  45         fprintf(stderr, "\n");
  46         fprintf(stderr, "Common remaining options:\n");
  47         fprintf(stderr, " [ action ACTION_SPEC ]\n");
  48         fprintf(stderr, " [ classid CLASSID ]\n");
  49         fprintf(stderr, "\n");
  50         fprintf(stderr, "Where BPF_BYTECODE := \'s,c t f k,c t f k,c t f k,...\'\n");
  51         fprintf(stderr, "c,t,f,k and s are decimals; s denotes number of 4-tuples\n");
  52         fprintf(stderr, "\n");
  53         fprintf(stderr, "Where FILE points to a file containing the BPF_BYTECODE string,\n");
  54         fprintf(stderr, "an ELF file containing eBPF map definitions and bytecode.\n");
  55         fprintf(stderr, "\n");
  56         fprintf(stderr, "Where CLS_NAME refers to the section name containing the\n");
  57         fprintf(stderr, "classifier (default \'%s\').\n", bpf_default_section(bpf_type));
  58         fprintf(stderr, "\n");
  59         fprintf(stderr, "Where UDS_FILE points to a unix domain socket file in order\n");
  60         fprintf(stderr, "to hand off control of all created eBPF maps to an agent.\n");
  61         fprintf(stderr, "\n");
  62         fprintf(stderr, "ACTION_SPEC := ... look at individual actions\n");
  63         fprintf(stderr, "NOTE: CLASSID is parsed as hexadecimal input.\n");
  64 }
  65
  66 static int bpf_parse_opt(struct filter_util *qu, char *handle,
  67                          int argc, char **argv, struct nlmsghdr *n)
  68 {
  69         struct tcmsg *t = NLMSG_DATA(n);
  70         const char *bpf_uds_name = NULL;
  71         const char *bpf_sec_name = NULL;
  72         unsigned int bpf_flags = 0;
  73         char *bpf_obj = NULL;
  74         struct rtattr *tail;
  75         bool seen_run = false;
  76         long h = 0;
  77         int ret = 0;
  78
  79         if (argc == 0)
  80                 return 0;
  81
  82         if (handle) {
  83                 h = strtol(handle, NULL, 0);
  84                 if (h == LONG_MIN || h == LONG_MAX) {
  85                         fprintf(stderr, "Illegal handle \"%s\", must be "
  86                                 "numeric.\n", handle);
  87                         return -1;
  88                 }
  89         }
  90
  91         t->tcm_handle = h;
  92
  93         tail = (struct rtattr *)(((void *)n) + NLMSG_ALIGN(n->nlmsg_len));
  94         addattr_l(n, MAX_MSG, TCA_OPTIONS, NULL, 0);
  95
  96         while (argc > 0) {
  97                 if (matches(*argv, "run") == 0) {
  98                         struct sock_filter bpf_ops[BPF_MAXINSNS];
  99                         bool from_file, ebpf, bpf_verbose;
 100                         int ret;
 101
 102                         NEXT_ARG();
 103 opt_bpf:
 104                         bpf_sec_name = bpf_default_section(bpf_type);
 105                         bpf_verbose = false;
 106                         ebpf = false;
 107                         seen_run = true;
 108
 109                         if (strcmp(*argv, "bytecode-file") == 0 ||
 110                             strcmp(*argv, "bcf") == 0) {
 111                                 from_file = true;
 112                         } else if (strcmp(*argv, "bytecode") == 0 ||
 113                                    strcmp(*argv, "bc") == 0) {
 114                                 from_file = false;
 115                         } else if (strcmp(*argv, "object-file") == 0 ||
 116                                    strcmp(*argv, "obj") == 0) {
 117                                 ebpf = true;
 118                         } else {
 119                                 fprintf(stderr, "What is \"%s\"?\n", *argv);
 120                                 explain();
 121                                 return -1;
 122                         }
 123
 124                         NEXT_ARG();
 125                         if (ebpf) {
 126                                 bpf_uds_name = getenv(BPF_ENV_UDS);
 127                                 bpf_obj = *argv;
 128
 129                                 NEXT_ARG_FWD();
 130
 131                                 if (argc > 0 &&
 132                                     (strcmp(*argv, "section") == 0 ||
 133                                      strcmp(*argv, "sec") == 0)) {
 134                                         NEXT_ARG();
 135                                         bpf_sec_name = *argv;
 136                                         NEXT_ARG_FWD();
 137                                 }
 138                                 if (argc > 0 && !bpf_uds_name &&
 139                                     (strcmp(*argv, "export") == 0 ||
 140                                      strcmp(*argv, "exp") == 0)) {
 141                                         NEXT_ARG();
 142                                         bpf_uds_name = *argv;
 143                                         NEXT_ARG_FWD();
 144                                 }
 145                                 if (argc > 0 &&
 146                                     (strcmp(*argv, "verbose") == 0 ||
 147                                      strcmp(*argv, "verb") == 0)) {
 148                                         bpf_verbose = true;
 149                                         NEXT_ARG_FWD();
 150                                 }
 151
 152                                 PREV_ARG();
 153                         }
 154
 155                         ret = ebpf ? bpf_open_object(bpf_obj, bpf_type, bpf_sec_name,
 156                                                      bpf_verbose) :
 157                                      bpf_parse_ops(argc, argv, bpf_ops, from_file);
 158                         if (ret < 0) {
 159                                 fprintf(stderr, "%s\n", ebpf ?
 160                                         "Could not load object" :
 161                                         "Illegal \"bytecode\"");
 162                                 return -1;
 163                         }
 164
 165                         if (ebpf) {
 166                                 char bpf_name[256];
 167
 168                                 bpf_obj = basename(bpf_obj);
 169
 170                                 snprintf(bpf_name, sizeof(bpf_name), "%s:[%s]",
 171                                          bpf_obj, bpf_sec_name);
 172
 173                                 addattr32(n, MAX_MSG, TCA_BPF_FD, ret);
 174                                 addattrstrz(n, MAX_MSG, TCA_BPF_NAME, bpf_name);
 175                         } else {
 176                                 addattr16(n, MAX_MSG, TCA_BPF_OPS_LEN, ret);
 177                                 addattr_l(n, MAX_MSG, TCA_BPF_OPS, &bpf_ops,
 178                                           ret * sizeof(struct sock_filter));
 179                         }
 180                 } else if (matches(*argv, "classid") == 0 ||
 181                            strcmp(*argv, "flowid") == 0) {
 182                         unsigned int handle;
 183
 184                         NEXT_ARG();
 185                         if (get_tc_classid(&handle, *argv)) {
 186                                 fprintf(stderr, "Illegal \"classid\"\n");
 187                                 return -1;
 188                         }
 189                         addattr32(n, MAX_MSG, TCA_BPF_CLASSID, handle);
 190                 } else if (matches(*argv, "direct-action") == 0 ||
 191                            matches(*argv, "da") == 0) {
 192                         bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
 193                 } else if (matches(*argv, "action") == 0) {
 194                         NEXT_ARG();
 195                         if (parse_action(&argc, &argv, TCA_BPF_ACT, n)) {
 196                                 fprintf(stderr, "Illegal \"action\"\n");
 197                                 return -1;
 198                         }
 199                         continue;
 200                 } else if (matches(*argv, "police") == 0) {
 201                         NEXT_ARG();
 202                         if (parse_police(&argc, &argv, TCA_BPF_POLICE, n)) {
 203                                 fprintf(stderr, "Illegal \"police\"\n");
 204                                 return -1;
 205                         }
 206                         continue;
 207                 } else if (strcmp(*argv, "help") == 0) {
 208                         explain();
 209                         return -1;
 210                 } else {
 211                         if (!seen_run)
 212                                 goto opt_bpf;
 213
 214                         fprintf(stderr, "What is \"%s\"?\n", *argv);
 215                         explain();
 216                         return -1;
 217                 }
 218
 219                 NEXT_ARG_FWD();
 220         }
 221
 222         if (bpf_obj && bpf_flags)
 223                 addattr32(n, MAX_MSG, TCA_BPF_FLAGS, bpf_flags);
 224
 225         tail->rta_len = (((void *)n) + n->nlmsg_len) - (void *)tail;
 226
 227         if (bpf_uds_name)
 228                 ret = bpf_send_map_fds(bpf_uds_name, bpf_obj);
 229
 230         return ret;
 231 }
 232
 233 static int bpf_print_opt(struct filter_util *qu, FILE *f,
 234                          struct rtattr *opt, __u32 handle)
 235 {
 236         struct rtattr *tb[TCA_BPF_MAX + 1];
 237
 238         if (opt == NULL)
 239                 return 0;
 240
 241         parse_rtattr_nested(tb, TCA_BPF_MAX, opt);
 242
 243         if (handle)
 244                 fprintf(f, "handle 0x%x ", handle);
 245
 246         if (tb[TCA_BPF_CLASSID]) {
 247                 SPRINT_BUF(b1);
 248                 fprintf(f, "flowid %s ",
 249                         sprint_tc_classid(rta_getattr_u32(tb[TCA_BPF_CLASSID]), b1));
 250         }
 251
 252         if (tb[TCA_BPF_NAME])
 253                 fprintf(f, "%s ", rta_getattr_str(tb[TCA_BPF_NAME]));
 254         else if (tb[TCA_BPF_FD])
 255                 fprintf(f, "pfd %u ", rta_getattr_u32(tb[TCA_BPF_FD]));
 256
 257         if (tb[TCA_BPF_FLAGS]) {
 258                 unsigned int flags = rta_getattr_u32(tb[TCA_BPF_FLAGS]);
 259
 260                 if (flags & TCA_BPF_FLAG_ACT_DIRECT)
 261                         fprintf(f, "direct-action ");
 262         }
 263
 264         if (tb[TCA_BPF_OPS] && tb[TCA_BPF_OPS_LEN]) {
 265                 bpf_print_ops(f, tb[TCA_BPF_OPS],
 266                               rta_getattr_u16(tb[TCA_BPF_OPS_LEN]));
 267                 fprintf(f, "\n");
 268         }
 269
 270         if (tb[TCA_BPF_POLICE]) {
 271                 fprintf(f, "\n");
 272                 tc_print_police(f, tb[TCA_BPF_POLICE]);
 273         }
 274
 275         if (tb[TCA_BPF_ACT]) {
 276                 tc_print_action(f, tb[TCA_BPF_ACT]);
 277         }
 278
 279         return 0;
 280 }
 281
 282 struct filter_util bpf_filter_util = {
 283         .id = "bpf",
 284         .parse_fopt = bpf_parse_opt,
 285         .print_fopt = bpf_print_opt,
 286 };