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 #include "tc_util.h"
  21 #include "tc_bpf.h"
  22
  23 static const enum bpf_prog_type bpf_type = BPF_PROG_TYPE_SCHED_ACT;
  24
  25 static const int nla_tbl[BPF_NLA_MAX] = {
  26         [BPF_NLA_OPS_LEN]       = TCA_ACT_BPF_OPS_LEN,
  27         [BPF_NLA_OPS]           = TCA_ACT_BPF_OPS,
  28         [BPF_NLA_FD]            = TCA_ACT_BPF_FD,
  29         [BPF_NLA_NAME]          = TCA_ACT_BPF_NAME,
  30 };
  31
  32 static void explain(void)
  33 {
  34         fprintf(stderr, "Usage: ... bpf ... [ index INDEX ]\n");
  35         fprintf(stderr, "\n");
  36         fprintf(stderr, "BPF use case:\n");
  37         fprintf(stderr, " bytecode BPF_BYTECODE\n");
  38         fprintf(stderr, " bytecode-file FILE\n");
  39         fprintf(stderr, "\n");
  40         fprintf(stderr, "eBPF use case:\n");
  41         fprintf(stderr, " object-file FILE [ section ACT_NAME ] [ export UDS_FILE ]");
  42         fprintf(stderr, " [ verbose ]\n");
  43         fprintf(stderr, " object-pinned FILE\n");
  44         fprintf(stderr, "\n");
  45         fprintf(stderr, "Where BPF_BYTECODE := \'s,c t f k,c t f k,c t f k,...\'\n");
  46         fprintf(stderr, "c,t,f,k and s are decimals; s denotes number of 4-tuples\n");
  47         fprintf(stderr, "\n");
  48         fprintf(stderr, "Where FILE points to a file containing the BPF_BYTECODE string,\n");
  49         fprintf(stderr, "an ELF file containing eBPF map definitions and bytecode, or a\n");
  50         fprintf(stderr, "pinned eBPF program.\n");
  51         fprintf(stderr, "\n");
  52         fprintf(stderr, "Where ACT_NAME refers to the section name containing the\n");
  53         fprintf(stderr, "action (default \'%s\').\n", bpf_default_section(bpf_type));
  54         fprintf(stderr, "\n");
  55         fprintf(stderr, "Where UDS_FILE points to a unix domain socket file in order\n");
  56         fprintf(stderr, "to hand off control of all created eBPF maps to an agent.\n");
  57         fprintf(stderr, "\n");
  58         fprintf(stderr, "Where optionally INDEX points to an existing action, or\n");
  59         fprintf(stderr, "explicitly specifies an action index upon creation.\n");
  60 }
  61
  62 static int bpf_parse_opt(struct action_util *a, int *ptr_argc, char ***ptr_argv,
  63                          int tca_id, struct nlmsghdr *n)
  64 {
  65         const char *bpf_obj = NULL, *bpf_uds_name = NULL;
  66         struct tc_act_bpf parm;
  67         bool seen_run = false;
  68         struct rtattr *tail;
  69         int argc, ret = 0;
  70         char **argv;
  71
  72         argv = *ptr_argv;
  73         argc = *ptr_argc;
  74
  75         if (matches(*argv, "bpf") != 0)
  76                 return -1;
  77
  78         NEXT_ARG();
  79
  80         tail = NLMSG_TAIL(n);
  81         addattr_l(n, MAX_MSG, tca_id, NULL, 0);
  82
  83         while (argc > 0) {
  84                 if (matches(*argv, "run") == 0) {
  85                         NEXT_ARG();
  86 opt_bpf:
  87                         seen_run = true;
  88                         if (bpf_parse_common(&argc, &argv, nla_tbl, bpf_type,
  89                                              &bpf_obj, &bpf_uds_name, n)) {
  90                                 fprintf(stderr, "Failed to retrieve (e)BPF data!\n");
  91                                 return -1;
  92                         }
  93                 } else if (matches(*argv, "help") == 0) {
  94                         explain();
  95                         return -1;
  96                 } else if (matches(*argv, "index") == 0) {
  97                         break;
  98                 } else {
  99                         if (!seen_run)
 100                                 goto opt_bpf;
 101                         break;
 102                 }
 103
 104                 NEXT_ARG_FWD();
 105         }
 106
 107         memset(&parm, 0, sizeof(parm));
 108         parm.action = TC_ACT_PIPE;
 109
 110         if (argc) {
 111                 if (matches(*argv, "reclassify") == 0) {
 112                         parm.action = TC_ACT_RECLASSIFY;
 113                         NEXT_ARG_FWD();
 114                 } else if (matches(*argv, "pipe") == 0) {
 115                         parm.action = TC_ACT_PIPE;
 116                         NEXT_ARG_FWD();
 117                 } else if (matches(*argv, "drop") == 0 ||
 118                            matches(*argv, "shot") == 0) {
 119                         parm.action = TC_ACT_SHOT;
 120                         NEXT_ARG_FWD();
 121                 } else if (matches(*argv, "continue") == 0) {
 122                         parm.action = TC_ACT_UNSPEC;
 123                         NEXT_ARG_FWD();
 124                 } else if (matches(*argv, "pass") == 0 ||
 125                            matches(*argv, "ok") == 0) {
 126                         parm.action = TC_ACT_OK;
 127                         NEXT_ARG_FWD();
 128                 }
 129         }
 130
 131         if (argc) {
 132                 if (matches(*argv, "index") == 0) {
 133                         NEXT_ARG();
 134                         if (get_u32(&parm.index, *argv, 10)) {
 135                                 fprintf(stderr, "bpf: Illegal \"index\"\n");
 136                                 return -1;
 137                         }
 138
 139                         NEXT_ARG_FWD();
 140                 }
 141         }
 142
 143         addattr_l(n, MAX_MSG, TCA_ACT_BPF_PARMS, &parm, sizeof(parm));
 144         tail->rta_len = (char *)NLMSG_TAIL(n) - (char *)tail;
 145
 146         if (bpf_uds_name)
 147                 ret = bpf_send_map_fds(bpf_uds_name, bpf_obj);
 148
 149         *ptr_argc = argc;
 150         *ptr_argv = argv;
 151
 152         return ret;
 153 }
 154
 155 static int bpf_print_opt(struct action_util *au, FILE *f, struct rtattr *arg)
 156 {
 157         struct rtattr *tb[TCA_ACT_BPF_MAX + 1];
 158         struct tc_act_bpf *parm;
 159         SPRINT_BUF(action_buf);
 160
 161         if (arg == NULL)
 162                 return -1;
 163
 164         parse_rtattr_nested(tb, TCA_ACT_BPF_MAX, arg);
 165
 166         if (!tb[TCA_ACT_BPF_PARMS]) {
 167                 fprintf(f, "[NULL bpf parameters]");
 168                 return -1;
 169         }
 170
 171         parm = RTA_DATA(tb[TCA_ACT_BPF_PARMS]);
 172         fprintf(f, "bpf ");
 173
 174         if (tb[TCA_ACT_BPF_NAME])
 175                 fprintf(f, "%s ", rta_getattr_str(tb[TCA_ACT_BPF_NAME]));
 176         else if (tb[TCA_ACT_BPF_FD])
 177                 fprintf(f, "pfd %u ", rta_getattr_u32(tb[TCA_ACT_BPF_FD]));
 178
 179         if (tb[TCA_ACT_BPF_OPS] && tb[TCA_ACT_BPF_OPS_LEN]) {
 180                 bpf_print_ops(f, tb[TCA_ACT_BPF_OPS],
 181                               rta_getattr_u16(tb[TCA_ACT_BPF_OPS_LEN]));
 182                 fprintf(f, " ");
 183         }
 184
 185         fprintf(f, "default-action %s\n", action_n2a(parm->action, action_buf,
 186                 sizeof(action_buf)));
 187         fprintf(f, "\tindex %d ref %d bind %d", parm->index, parm->refcnt,
 188                 parm->bindcnt);
 189
 190         if (show_stats) {
 191                 if (tb[TCA_ACT_BPF_TM]) {
 192                         struct tcf_t *tm = RTA_DATA(tb[TCA_ACT_BPF_TM]);
 193                         print_tm(f, tm);
 194                 }
 195         }
 196
 197         fprintf(f, "\n ");
 198         return 0;
 199 }
 200
 201 struct action_util bpf_action_util = {
 202         .id             = "bpf",
 203         .parse_aopt     = bpf_parse_opt,
 204         .print_aopt     = bpf_print_opt,
 205 };