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 = { .action = TC_ACT_PIPE };
  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 = NLMSG_TAIL(n);
  94         addattr_l(n, MAX_MSG, tca_id, NULL, 0);
  95
  96         while (argc > 0) {
  97                 if (matches(*argv, "run") == 0) {
  98                         NEXT_ARG();
  99 opt_bpf:
 100                         seen_run = true;
 101                         cfg.argc = argc;
 102                         cfg.argv = argv;
 103
 104                         if (bpf_parse_common(bpf_type, &cfg, &bpf_cb_ops, n))
 105                                 return -1;
 106
 107                         argc = cfg.argc;
 108                         argv = cfg.argv;
 109
 110                         bpf_obj = cfg.object;
 111                         bpf_uds_name = cfg.uds;
 112                 } else if (matches(*argv, "help") == 0) {
 113                         explain();
 114                         return -1;
 115                 } else if (matches(*argv, "index") == 0) {
 116                         break;
 117                 } else {
 118                         if (!seen_run)
 119                                 goto opt_bpf;
 120                         break;
 121                 }
 122
 123                 NEXT_ARG_FWD();
 124         }
 125
 126         if (argc && !action_a2n(*argv, &parm.action, false))
 127                 NEXT_ARG_FWD();
 128
 129         if (argc) {
 130                 if (matches(*argv, "index") == 0) {
 131                         NEXT_ARG();
 132                         if (get_u32(&parm.index, *argv, 10)) {
 133                                 fprintf(stderr, "bpf: Illegal \"index\"\n");
 134                                 return -1;
 135                         }
 136
 137                         NEXT_ARG_FWD();
 138                 }
 139         }
 140
 141         addattr_l(n, MAX_MSG, TCA_ACT_BPF_PARMS, &parm, sizeof(parm));
 142         tail->rta_len = (char *)NLMSG_TAIL(n) - (char *)tail;
 143
 144         if (bpf_uds_name)
 145                 ret = bpf_send_map_fds(bpf_uds_name, bpf_obj);
 146
 147         *ptr_argc = argc;
 148         *ptr_argv = argv;
 149
 150         return ret;
 151 }
 152
 153 static int bpf_print_opt(struct action_util *au, FILE *f, struct rtattr *arg)
 154 {
 155         struct rtattr *tb[TCA_ACT_BPF_MAX + 1];
 156         struct tc_act_bpf *parm;
 157
 158         if (arg == NULL)
 159                 return -1;
 160
 161         parse_rtattr_nested(tb, TCA_ACT_BPF_MAX, arg);
 162
 163         if (!tb[TCA_ACT_BPF_PARMS]) {
 164                 fprintf(f, "[NULL bpf parameters]");
 165                 return -1;
 166         }
 167
 168         parm = RTA_DATA(tb[TCA_ACT_BPF_PARMS]);
 169         fprintf(f, "bpf ");
 170
 171         if (tb[TCA_ACT_BPF_NAME])
 172                 fprintf(f, "%s ", rta_getattr_str(tb[TCA_ACT_BPF_NAME]));
 173
 174         if (tb[TCA_ACT_BPF_OPS] && tb[TCA_ACT_BPF_OPS_LEN]) {
 175                 bpf_print_ops(f, tb[TCA_ACT_BPF_OPS],
 176                               rta_getattr_u16(tb[TCA_ACT_BPF_OPS_LEN]));
 177                 fprintf(f, " ");
 178         }
 179
 180         fprintf(f, "default-action %s\n", action_n2a(parm->action));
 181         fprintf(f, "\tindex %d ref %d bind %d", parm->index, parm->refcnt,
 182                 parm->bindcnt);
 183
 184         if (show_stats) {
 185                 if (tb[TCA_ACT_BPF_TM]) {
 186                         struct tcf_t *tm = RTA_DATA(tb[TCA_ACT_BPF_TM]);
 187
 188                         print_tm(f, tm);
 189                 }
 190         }
 191
 192         fprintf(f, "\n ");
 193         return 0;
 194 }
 195
 196 struct action_util bpf_action_util = {
 197         .id             = "bpf",
 198         .parse_aopt     = bpf_parse_opt,
 199         .print_aopt     = bpf_print_opt,
 200 };