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
  16 #include <linux/bpf.h>
  17 #include <linux/tc_act/tc_bpf.h>
  18
  19 #include "utils.h"
  20
  21 #include "tc_util.h"
  22 #include "bpf_util.h"
  23
  24 static const enum bpf_prog_type bpf_type = BPF_PROG_TYPE_SCHED_ACT;
  25
  26 static void explain(void)
  27 {
  28         fprintf(stderr, "Usage: ... bpf ... [ index INDEX ]\n");
  29         fprintf(stderr, "\n");
  30         fprintf(stderr, "BPF use case:\n");
  31         fprintf(stderr, " bytecode BPF_BYTECODE\n");
  32         fprintf(stderr, " bytecode-file FILE\n");
  33         fprintf(stderr, "\n");
  34         fprintf(stderr, "eBPF use case:\n");
  35         fprintf(stderr, " object-file FILE [ section ACT_NAME ] [ export UDS_FILE ]");
  36         fprintf(stderr, " [ verbose ]\n");
  37         fprintf(stderr, " object-pinned FILE\n");
  38         fprintf(stderr, "\n");
  39         fprintf(stderr, "Where BPF_BYTECODE := \'s,c t f k,c t f k,c t f k,...\'\n");
  40         fprintf(stderr, "c,t,f,k and s are decimals; s denotes number of 4-tuples\n");
  41         fprintf(stderr, "\n");
  42         fprintf(stderr, "Where FILE points to a file containing the BPF_BYTECODE string,\n");
  43         fprintf(stderr, "an ELF file containing eBPF map definitions and bytecode, or a\n");
  44         fprintf(stderr, "pinned eBPF program.\n");
  45         fprintf(stderr, "\n");
  46         fprintf(stderr, "Where ACT_NAME refers to the section name containing the\n");
  47         fprintf(stderr, "action (default \'%s\').\n", bpf_prog_to_default_section(bpf_type));
  48         fprintf(stderr, "\n");
  49         fprintf(stderr, "Where UDS_FILE points to a unix domain socket file in order\n");
  50         fprintf(stderr, "to hand off control of all created eBPF maps to an agent.\n");
  51         fprintf(stderr, "\n");
  52         fprintf(stderr, "Where optionally INDEX points to an existing action, or\n");
  53         fprintf(stderr, "explicitly specifies an action index upon creation.\n");
  54 }
  55
  56 static void bpf_cbpf_cb(void *nl, const struct sock_filter *ops, int ops_len)
  57 {
  58         addattr16(nl, MAX_MSG, TCA_ACT_BPF_OPS_LEN, ops_len);
  59         addattr_l(nl, MAX_MSG, TCA_ACT_BPF_OPS, ops,
  60                   ops_len * sizeof(struct sock_filter));
  61 }
  62
  63 static void bpf_ebpf_cb(void *nl, int fd, const char *annotation)
  64 {
  65         addattr32(nl, MAX_MSG, TCA_ACT_BPF_FD, fd);
  66         addattrstrz(nl, MAX_MSG, TCA_ACT_BPF_NAME, annotation);
  67 }
  68
  69 static const struct bpf_cfg_ops bpf_cb_ops = {
  70         .cbpf_cb = bpf_cbpf_cb,
  71         .ebpf_cb = bpf_ebpf_cb,
  72 };
  73
  74 static int bpf_parse_opt(struct action_util *a, int *ptr_argc, char ***ptr_argv,
  75                          int tca_id, struct nlmsghdr *n)
  76 {
  77         const char *bpf_obj = NULL, *bpf_uds_name = NULL;
  78         struct tc_act_bpf parm = {};
  79         struct bpf_cfg_in cfg = {};
  80         bool seen_run = false;
  81         struct rtattr *tail;
  82         int argc, ret = 0;
  83         char **argv;
  84
  85         argv = *ptr_argv;
  86         argc = *ptr_argc;
  87
  88         if (matches(*argv, "bpf") != 0)
  89                 return -1;
  90
  91         NEXT_ARG();
  92
  93         tail = addattr_nest(n, MAX_MSG, tca_id);
  94
  95         while (argc > 0) {
  96                 if (matches(*argv, "run") == 0) {
  97                         NEXT_ARG();
  98
  99                         if (seen_run)
 100                                 duparg("run", *argv);
 101 opt_bpf:
 102                         seen_run = true;
 103                         cfg.type = bpf_type;
 104                         cfg.argc = argc;
 105                         cfg.argv = argv;
 106
 107                         if (bpf_parse_and_load_common(&cfg, &bpf_cb_ops, n))
 108                                 return -1;
 109
 110                         argc = cfg.argc;
 111                         argv = cfg.argv;
 112
 113                         bpf_obj = cfg.object;
 114                         bpf_uds_name = cfg.uds;
 115                 } else if (matches(*argv, "help") == 0) {
 116                         explain();
 117                         return -1;
 118                 } else if (matches(*argv, "index") == 0) {
 119                         break;
 120                 } else {
 121                         if (!seen_run)
 122                                 goto opt_bpf;
 123                         break;
 124                 }
 125
 126                 NEXT_ARG_FWD();
 127         }
 128
 129         parse_action_control_dflt(&argc, &argv, &parm.action,
 130                                   false, TC_ACT_PIPE);
 131
 132         if (argc) {
 133                 if (matches(*argv, "index") == 0) {
 134                         NEXT_ARG();
 135                         if (get_u32(&parm.index, *argv, 10)) {
 136                                 fprintf(stderr, "bpf: Illegal \"index\"\n");
 137                                 return -1;
 138                         }
 139
 140                         NEXT_ARG_FWD();
 141                 }
 142         }
 143
 144         addattr_l(n, MAX_MSG, TCA_ACT_BPF_PARMS, &parm, sizeof(parm));
 145         addattr_nest_end(n, tail);
 146
 147         if (bpf_uds_name)
 148                 ret = bpf_send_map_fds(bpf_uds_name, bpf_obj);
 149
 150         *ptr_argc = argc;
 151         *ptr_argv = argv;
 152
 153         return ret;
 154 }
 155
 156 static int bpf_print_opt(struct action_util *au, FILE *f, struct rtattr *arg)
 157 {
 158         struct rtattr *tb[TCA_ACT_BPF_MAX + 1];
 159         struct tc_act_bpf *parm;
 160         int d_ok = 0;
 161
 162         if (arg == NULL)
 163                 return -1;
 164
 165         parse_rtattr_nested(tb, TCA_ACT_BPF_MAX, arg);
 166
 167         if (!tb[TCA_ACT_BPF_PARMS]) {
 168                 fprintf(f, "[NULL bpf parameters]");
 169                 return -1;
 170         }
 171
 172         parm = RTA_DATA(tb[TCA_ACT_BPF_PARMS]);
 173         print_string(PRINT_ANY, "kind", "%s ", "bpf");
 174
 175         if (tb[TCA_ACT_BPF_NAME])
 176                 print_string(PRINT_ANY, "bpf_name", "%s ",
 177                              rta_getattr_str(tb[TCA_ACT_BPF_NAME]));
 178         if (tb[TCA_ACT_BPF_OPS] && tb[TCA_ACT_BPF_OPS_LEN]) {
 179                 bpf_print_ops(tb[TCA_ACT_BPF_OPS],
 180                               rta_getattr_u16(tb[TCA_ACT_BPF_OPS_LEN]));
 181                 print_string(PRINT_FP, NULL, "%s", " ");
 182         }
 183
 184         if (tb[TCA_ACT_BPF_ID])
 185                 d_ok = bpf_dump_prog_info(f,
 186                                           rta_getattr_u32(tb[TCA_ACT_BPF_ID]));
 187         if (!d_ok && tb[TCA_ACT_BPF_TAG]) {
 188                 SPRINT_BUF(b);
 189
 190                 print_string(PRINT_ANY, "tag", "tag %s ",
 191                              hexstring_n2a(RTA_DATA(tb[TCA_ACT_BPF_TAG]),
 192                              RTA_PAYLOAD(tb[TCA_ACT_BPF_TAG]),
 193                              b, sizeof(b)));
 194         }
 195
 196         print_action_control(f, "default-action ", parm->action, _SL_);
 197         print_uint(PRINT_ANY, "index", "\t index %u", parm->index);
 198         print_int(PRINT_ANY, "ref", " ref %d", parm->refcnt);
 199         print_int(PRINT_ANY, "bind", " bind %d", parm->bindcnt);
 200
 201         if (show_stats) {
 202                 if (tb[TCA_ACT_BPF_TM]) {
 203                         struct tcf_t *tm = RTA_DATA(tb[TCA_ACT_BPF_TM]);
 204
 205                         print_tm(f, tm);
 206                 }
 207         }
 208
 209         fprintf(f, "\n ");
 210         return 0;
 211 }
 212
 213 struct action_util bpf_action_util = {
 214         .id             = "bpf",
 215         .parse_aopt     = bpf_parse_opt,
 216         .print_aopt     = bpf_print_opt,
 217 };