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 <sys/socket.h>
  18 #include <netinet/in.h>
  19 #include <arpa/inet.h>
  20 #include <string.h>
  21 #include <stdbool.h>
  22 #include <errno.h>
  23 #include <limits.h>
  24 #include <linux/filter.h>
  25 #include <linux/if.h>
  26
  27 #include "utils.h"
  28 #include "tc_util.h"
  29 #include "tc_bpf.h"
  30
  31 static void explain(void)
  32 {
  33         fprintf(stderr, "Usage: ... bpf ...\n");
  34         fprintf(stderr, "\n");
  35         fprintf(stderr, " [inline]:     run bytecode BPF_BYTECODE\n");
  36         fprintf(stderr, " [from file]:  run bytecode-file FILE\n");
  37         fprintf(stderr, " [from file]:  run object-file FILE\n");
  38         fprintf(stderr, "\n");
  39         fprintf(stderr, "               [ action ACTION_SPEC ]\n");
  40         fprintf(stderr, "               [ classid CLASSID ]\n");
  41         fprintf(stderr, "\n");
  42         fprintf(stderr, "Where BPF_BYTECODE := \'s,c t f k,c t f k,c t f k,...\'\n");
  43         fprintf(stderr, "      c,t,f,k and s are decimals; s denotes number of 4-tuples\n");
  44         fprintf(stderr, "Where FILE points to a file containing the BPF_BYTECODE string,\n");
  45         fprintf(stderr, "or an ELF file containing eBPF map definitions and bytecode.\n");
  46         fprintf(stderr, "\nACTION_SPEC := ... look at individual actions\n");
  47         fprintf(stderr, "NOTE: CLASSID is parsed as hexadecimal input.\n");
  48 }
  49
  50 static int bpf_parse_opt(struct filter_util *qu, char *handle,
  51                          int argc, char **argv, struct nlmsghdr *n)
  52 {
  53         struct tcmsg *t = NLMSG_DATA(n);
  54         struct rtattr *tail;
  55         long h = 0;
  56
  57         if (argc == 0)
  58                 return 0;
  59
  60         if (handle) {
  61                 h = strtol(handle, NULL, 0);
  62                 if (h == LONG_MIN || h == LONG_MAX) {
  63                         fprintf(stderr, "Illegal handle \"%s\", must be "
  64                                 "numeric.\n", handle);
  65                         return -1;
  66                 }
  67         }
  68
  69         t->tcm_handle = h;
  70
  71         tail = (struct rtattr*)(((void*)n)+NLMSG_ALIGN(n->nlmsg_len));
  72         addattr_l(n, MAX_MSG, TCA_OPTIONS, NULL, 0);
  73
  74         while (argc > 0) {
  75                 if (matches(*argv, "run") == 0) {
  76                         bool from_file = true, ebpf;
  77                         struct sock_filter bpf_ops[BPF_MAXINSNS];
  78                         int ret;
  79
  80                         NEXT_ARG();
  81                         if (strcmp(*argv, "bytecode-file") == 0) {
  82                                 ebpf = false;
  83                         } else if (strcmp(*argv, "bytecode") == 0) {
  84                                 from_file = false;
  85                                 ebpf = false;
  86                         } else if (strcmp(*argv, "object-file") == 0) {
  87                                 ebpf = true;
  88                         } else {
  89                                 fprintf(stderr, "What is \"%s\"?\n", *argv);
  90                                 explain();
  91                                 return -1;
  92                         }
  93                         NEXT_ARG();
  94                         ret = ebpf ? bpf_open_object(*argv, BPF_PROG_TYPE_SCHED_CLS) :
  95                                      bpf_parse_ops(argc, argv, bpf_ops, from_file);
  96                         if (ret < 0) {
  97                                 fprintf(stderr, "%s\n", ebpf ?
  98                                         "Could not load object" :
  99                                         "Illegal \"bytecode\"");
 100                                 return -1;
 101                         }
 102                         if (ebpf) {
 103                                 addattr32(n, MAX_MSG, TCA_BPF_FD, ret);
 104                                 addattrstrz(n, MAX_MSG, TCA_BPF_NAME, *argv);
 105                         } else {
 106                                 addattr16(n, MAX_MSG, TCA_BPF_OPS_LEN, ret);
 107                                 addattr_l(n, MAX_MSG, TCA_BPF_OPS, &bpf_ops,
 108                                           ret * sizeof(struct sock_filter));
 109                         }
 110                 } else if (matches(*argv, "classid") == 0 ||
 111                            strcmp(*argv, "flowid") == 0) {
 112                         unsigned handle;
 113                         NEXT_ARG();
 114                         if (get_tc_classid(&handle, *argv)) {
 115                                 fprintf(stderr, "Illegal \"classid\"\n");
 116                                 return -1;
 117                         }
 118                         addattr_l(n, MAX_MSG, TCA_BPF_CLASSID, &handle, 4);
 119                 } else if (matches(*argv, "action") == 0) {
 120                         NEXT_ARG();
 121                         if (parse_action(&argc, &argv, TCA_BPF_ACT, n)) {
 122                                 fprintf(stderr, "Illegal \"action\"\n");
 123                                 return -1;
 124                         }
 125                         continue;
 126                 } else if (matches(*argv, "police") == 0) {
 127                         NEXT_ARG();
 128                         if (parse_police(&argc, &argv, TCA_BPF_POLICE, n)) {
 129                                 fprintf(stderr, "Illegal \"police\"\n");
 130                                 return -1;
 131                         }
 132                         continue;
 133                 } else if (strcmp(*argv, "help") == 0) {
 134                         explain();
 135                         return -1;
 136                 } else {
 137                         fprintf(stderr, "What is \"%s\"?\n", *argv);
 138                         explain();
 139                         return -1;
 140                 }
 141                 argc--; argv++;
 142         }
 143
 144         tail->rta_len = (((void*)n)+n->nlmsg_len) - (void*)tail;
 145         return 0;
 146 }
 147
 148 static int bpf_print_opt(struct filter_util *qu, FILE *f,
 149                          struct rtattr *opt, __u32 handle)
 150 {
 151         struct rtattr *tb[TCA_BPF_MAX + 1];
 152
 153         if (opt == NULL)
 154                 return 0;
 155
 156         parse_rtattr_nested(tb, TCA_BPF_MAX, opt);
 157
 158         if (handle)
 159                 fprintf(f, "handle 0x%x ", handle);
 160
 161         if (tb[TCA_BPF_CLASSID]) {
 162                 SPRINT_BUF(b1);
 163                 fprintf(f, "flowid %s ",
 164                         sprint_tc_classid(rta_getattr_u32(tb[TCA_BPF_CLASSID]), b1));
 165         }
 166
 167         if (tb[TCA_BPF_NAME])
 168                 fprintf(f, "%s ", rta_getattr_str(tb[TCA_BPF_NAME]));
 169         else if (tb[TCA_BPF_FD])
 170                 fprintf(f, "pfd %u ", rta_getattr_u32(tb[TCA_BPF_FD]));
 171
 172         if (tb[TCA_BPF_OPS] && tb[TCA_BPF_OPS_LEN])
 173                 bpf_print_ops(f, tb[TCA_BPF_OPS],
 174                               rta_getattr_u16(tb[TCA_BPF_OPS_LEN]));
 175
 176         if (tb[TCA_BPF_POLICE]) {
 177                 fprintf(f, "\n");
 178                 tc_print_police(f, tb[TCA_BPF_POLICE]);
 179         }
 180
 181         if (tb[TCA_BPF_ACT]) {
 182                 tc_print_action(f, tb[TCA_BPF_ACT]);
 183         }
 184
 185         return 0;
 186 }
 187
 188 struct filter_util bpf_filter_util = {
 189         .id = "bpf",
 190         .parse_fopt = bpf_parse_opt,
 191         .print_fopt = bpf_print_opt,
 192 };