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
  15 #include <linux/bpf.h>
  16
  17 #include "utils.h"
  18 #include "tc_util.h"
  19 #include "tc_bpf.h"
  20
  21 static const enum bpf_prog_type bpf_type = BPF_PROG_TYPE_SCHED_CLS;
  22
  23 static const int nla_tbl[BPF_NLA_MAX] = {
  24         [BPF_NLA_OPS_LEN]       = TCA_BPF_OPS_LEN,
  25         [BPF_NLA_OPS]           = TCA_BPF_OPS,
  26         [BPF_NLA_FD]            = TCA_BPF_FD,
  27         [BPF_NLA_NAME]          = TCA_BPF_NAME,
  28 };
  29
  30 static void explain(void)
  31 {
  32         fprintf(stderr, "Usage: ... bpf ...\n");
  33         fprintf(stderr, "\n");
  34         fprintf(stderr, "BPF use case:\n");
  35         fprintf(stderr, " bytecode BPF_BYTECODE\n");
  36         fprintf(stderr, " bytecode-file FILE\n");
  37         fprintf(stderr, "\n");
  38         fprintf(stderr, "eBPF use case:\n");
  39         fprintf(stderr, " object-file FILE [ section CLS_NAME ] [ export UDS_FILE ]");
  40         fprintf(stderr, " [ verbose ] [ direct-action ]\n");
  41         fprintf(stderr, " object-pinned FILE [ direct-action ]\n");
  42         fprintf(stderr, "\n");
  43         fprintf(stderr, "Common remaining options:\n");
  44         fprintf(stderr, " [ action ACTION_SPEC ]\n");
  45         fprintf(stderr, " [ classid CLASSID ]\n");
  46         fprintf(stderr, "\n");
  47         fprintf(stderr, "Where BPF_BYTECODE := \'s,c t f k,c t f k,c t f k,...\'\n");
  48         fprintf(stderr, "c,t,f,k and s are decimals; s denotes number of 4-tuples\n");
  49         fprintf(stderr, "\n");
  50         fprintf(stderr, "Where FILE points to a file containing the BPF_BYTECODE string,\n");
  51         fprintf(stderr, "an ELF file containing eBPF map definitions and bytecode, or a\n");
  52         fprintf(stderr, "pinned eBPF program.\n");
  53         fprintf(stderr, "\n");
  54         fprintf(stderr, "Where CLS_NAME refers to the section name containing the\n");
  55         fprintf(stderr, "classifier (default \'%s\').\n", bpf_default_section(bpf_type));
  56         fprintf(stderr, "\n");
  57         fprintf(stderr, "Where UDS_FILE points to a unix domain socket file in order\n");
  58         fprintf(stderr, "to hand off control of all created eBPF maps to an agent.\n");
  59         fprintf(stderr, "\n");
  60         fprintf(stderr, "ACTION_SPEC := ... look at individual actions\n");
  61         fprintf(stderr, "NOTE: CLASSID is parsed as hexadecimal input.\n");
  62 }
  63
  64 static int bpf_parse_opt(struct filter_util *qu, char *handle,
  65                          int argc, char **argv, struct nlmsghdr *n)
  66 {
  67         const char *bpf_obj = NULL, *bpf_uds_name = NULL;
  68         struct tcmsg *t = NLMSG_DATA(n);
  69         unsigned int bpf_flags = 0;
  70         bool seen_run = false;
  71         struct rtattr *tail;
  72         int ret = 0;
  73
  74         if (argc == 0)
  75                 return 0;
  76
  77         if (handle) {
  78                 if (get_u32(&t->tcm_handle, handle, 0)) {
  79                         fprintf(stderr, "Illegal \"handle\"\n");
  80                         return -1;
  81                 }
  82         }
  83
  84         tail = (struct rtattr *)(((void *)n) + NLMSG_ALIGN(n->nlmsg_len));
  85         addattr_l(n, MAX_MSG, TCA_OPTIONS, NULL, 0);
  86
  87         while (argc > 0) {
  88                 if (matches(*argv, "run") == 0) {
  89                         NEXT_ARG();
  90 opt_bpf:
  91                         seen_run = true;
  92                         if (bpf_parse_common(&argc, &argv, nla_tbl, bpf_type,
  93                                              &bpf_obj, &bpf_uds_name, n)) {
  94                                 fprintf(stderr, "Failed to retrieve (e)BPF data!\n");
  95                                 return -1;
  96                         }
  97                 } else if (matches(*argv, "classid") == 0 ||
  98                            matches(*argv, "flowid") == 0) {
  99                         unsigned int handle;
 100
 101                         NEXT_ARG();
 102                         if (get_tc_classid(&handle, *argv)) {
 103                                 fprintf(stderr, "Illegal \"classid\"\n");
 104                                 return -1;
 105                         }
 106                         addattr32(n, MAX_MSG, TCA_BPF_CLASSID, handle);
 107                 } else if (matches(*argv, "direct-action") == 0 ||
 108                            matches(*argv, "da") == 0) {
 109                         bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
 110                 } else if (matches(*argv, "action") == 0) {
 111                         NEXT_ARG();
 112                         if (parse_action(&argc, &argv, TCA_BPF_ACT, n)) {
 113                                 fprintf(stderr, "Illegal \"action\"\n");
 114                                 return -1;
 115                         }
 116                         continue;
 117                 } else if (matches(*argv, "police") == 0) {
 118                         NEXT_ARG();
 119                         if (parse_police(&argc, &argv, TCA_BPF_POLICE, n)) {
 120                                 fprintf(stderr, "Illegal \"police\"\n");
 121                                 return -1;
 122                         }
 123                         continue;
 124                 } else if (matches(*argv, "help") == 0) {
 125                         explain();
 126                         return -1;
 127                 } else {
 128                         if (!seen_run)
 129                                 goto opt_bpf;
 130
 131                         fprintf(stderr, "What is \"%s\"?\n", *argv);
 132                         explain();
 133                         return -1;
 134                 }
 135
 136                 NEXT_ARG_FWD();
 137         }
 138
 139         if (bpf_obj && bpf_flags)
 140                 addattr32(n, MAX_MSG, TCA_BPF_FLAGS, bpf_flags);
 141
 142         tail->rta_len = (((void *)n) + n->nlmsg_len) - (void *)tail;
 143
 144         if (bpf_uds_name)
 145                 ret = bpf_send_map_fds(bpf_uds_name, bpf_obj);
 146
 147         return ret;
 148 }
 149
 150 static int bpf_print_opt(struct filter_util *qu, FILE *f,
 151                          struct rtattr *opt, __u32 handle)
 152 {
 153         struct rtattr *tb[TCA_BPF_MAX + 1];
 154
 155         if (opt == NULL)
 156                 return 0;
 157
 158         parse_rtattr_nested(tb, TCA_BPF_MAX, opt);
 159
 160         if (handle)
 161                 fprintf(f, "handle 0x%x ", handle);
 162
 163         if (tb[TCA_BPF_CLASSID]) {
 164                 SPRINT_BUF(b1);
 165                 fprintf(f, "flowid %s ",
 166                         sprint_tc_classid(rta_getattr_u32(tb[TCA_BPF_CLASSID]), b1));
 167         }
 168
 169         if (tb[TCA_BPF_NAME])
 170                 fprintf(f, "%s ", rta_getattr_str(tb[TCA_BPF_NAME]));
 171         else if (tb[TCA_BPF_FD])
 172                 fprintf(f, "pfd %u ", rta_getattr_u32(tb[TCA_BPF_FD]));
 173
 174         if (tb[TCA_BPF_FLAGS]) {
 175                 unsigned int flags = rta_getattr_u32(tb[TCA_BPF_FLAGS]);
 176
 177                 if (flags & TCA_BPF_FLAG_ACT_DIRECT)
 178                         fprintf(f, "direct-action ");
 179         }
 180
 181         if (tb[TCA_BPF_OPS] && tb[TCA_BPF_OPS_LEN]) {
 182                 bpf_print_ops(f, tb[TCA_BPF_OPS],
 183                               rta_getattr_u16(tb[TCA_BPF_OPS_LEN]));
 184                 fprintf(f, "\n");
 185         }
 186
 187         if (tb[TCA_BPF_POLICE]) {
 188                 fprintf(f, "\n");
 189                 tc_print_police(f, tb[TCA_BPF_POLICE]);
 190         }
 191
 192         if (tb[TCA_BPF_ACT]) {
 193                 tc_print_action(f, tb[TCA_BPF_ACT]);
 194         }
 195
 196         return 0;
 197 }
 198
 199 struct filter_util bpf_filter_util = {
 200         .id             = "bpf",
 201         .parse_fopt     = bpf_parse_opt,
 202         .print_fopt     = bpf_print_opt,
 203 };