tc/m_skbmod.c

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /*
   3  * m_skbmod.c   skb modifier action module
   4  *
   5  * Authors:  J Hadi Salim (jhs@mojatatu.com)
   6  */
   7
   8 #include <stdio.h>
   9 #include <stdlib.h>
  10 #include <unistd.h>
  11 #include <fcntl.h>
  12 #include <sys/socket.h>
  13 #include <netinet/in.h>
  14 #include <arpa/inet.h>
  15 #include <string.h>
  16 #include <linux/netdevice.h>
  17
  18 #include "rt_names.h"
  19 #include "utils.h"
  20 #include "tc_util.h"
  21 #include <linux/tc_act/tc_skbmod.h>
  22
  23 static void skbmod_explain(void)
  24 {
  25         fprintf(stderr,
  26                 "Usage:... skbmod { set <SETTABLE> | swap <SWAPPABLE> | ecn } [CONTROL] [index INDEX]\n"
  27                 "where SETTABLE is: [dmac DMAC] [smac SMAC] [etype ETYPE]\n"
  28                 "where SWAPPABLE is: \"mac\" to swap mac addresses\n"
  29                 "\tDMAC := 6 byte Destination MAC address\n"
  30                 "\tSMAC := optional 6 byte Source MAC address\n"
  31                 "\tETYPE := optional 16 bit ethertype\n"
  32                 "\tCONTROL := reclassify | pipe | drop | continue | ok |\n"
  33                 "\t           goto chain <CHAIN_INDEX>\n"
  34                 "\tINDEX := skbmod index value to use\n");
  35 }
  36
  37 static void skbmod_usage(void)
  38 {
  39         skbmod_explain();
  40         exit(-1);
  41 }
  42
  43 static int parse_skbmod(const struct action_util *a, int *argc_p, char ***argv_p,
  44                         int tca_id, struct nlmsghdr *n)
  45 {
  46         int argc = *argc_p;
  47         char **argv = *argv_p;
  48         int ok = 0;
  49         struct tc_skbmod p;
  50         struct rtattr *tail;
  51         char dbuf[ETH_ALEN];
  52         char sbuf[ETH_ALEN];
  53         __u16 skbmod_etype = 0;
  54         char *daddr = NULL;
  55         char *saddr = NULL;
  56
  57         memset(&p, 0, sizeof(p));
  58
  59         if (argc <= 0)
  60                 return -1;
  61
  62         while (argc > 0) {
  63                 if (matches(*argv, "skbmod") == 0) {
  64                         NEXT_ARG();
  65                         continue;
  66                 } else if (matches(*argv, "swap") == 0) {
  67                         NEXT_ARG();
  68                         continue;
  69                 } else if (matches(*argv, "mac") == 0) {
  70                         p.flags |= SKBMOD_F_SWAPMAC;
  71                         ok += 1;
  72                 } else if (matches(*argv, "set") == 0) {
  73                         NEXT_ARG();
  74                         continue;
  75                 } else if (matches(*argv, "etype") == 0) {
  76                         NEXT_ARG();
  77                         if (get_u16(&skbmod_etype, *argv, 0))
  78                                 invarg("ethertype is invalid", *argv);
  79                         fprintf(stderr, "skbmod etype 0x%x\n", skbmod_etype);
  80                         p.flags |= SKBMOD_F_ETYPE;
  81                         ok += 1;
  82                 } else if (matches(*argv, "dmac") == 0) {
  83                         NEXT_ARG();
  84                         daddr = *argv;
  85                         if (sscanf(daddr, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx",
  86                                    dbuf, dbuf + 1, dbuf + 2,
  87                                    dbuf + 3, dbuf + 4, dbuf + 5) != 6) {
  88                                 fprintf(stderr, "Invalid dst mac address %s\n",
  89                                         daddr);
  90                                 return -1;
  91                         }
  92                         p.flags |= SKBMOD_F_DMAC;
  93                         fprintf(stderr, "dst MAC address <%s>\n", daddr);
  94                         ok += 1;
  95
  96                 } else if (matches(*argv, "smac") == 0) {
  97                         NEXT_ARG();
  98                         saddr = *argv;
  99                         if (sscanf(saddr, "%hhx:%hhx:%hhx:%hhx:%hhx:%hhx",
 100                                    sbuf, sbuf + 1, sbuf + 2,
 101                                    sbuf + 3, sbuf + 4, sbuf + 5) != 6) {
 102                                 fprintf(stderr, "Invalid smac address %s\n",
 103                                         saddr);
 104                                 return -1;
 105                         }
 106                         p.flags |= SKBMOD_F_SMAC;
 107                         fprintf(stderr, "src MAC address <%s>\n", saddr);
 108                         ok += 1;
 109                 } else if (matches(*argv, "ecn") == 0) {
 110                         p.flags |= SKBMOD_F_ECN;
 111                         ok += 1;
 112                 } else if (matches(*argv, "help") == 0) {
 113                         skbmod_usage();
 114                 } else {
 115                         break;
 116                 }
 117
 118                 argc--;
 119                 argv++;
 120         }
 121
 122         parse_action_control_dflt(&argc, &argv, &p.action, false, TC_ACT_PIPE);
 123
 124         if (argc) {
 125                 if (matches(*argv, "index") == 0) {
 126                         NEXT_ARG();
 127                         if (get_u32(&p.index, *argv, 0)) {
 128                                 fprintf(stderr, "skbmod: Illegal \"index\"\n");
 129                                 return -1;
 130                         }
 131                         ok++;
 132                         argc--;
 133                         argv++;
 134                 }
 135         }
 136
 137         if (!ok) {
 138                 fprintf(stderr, "skbmod requires at least one option\n");
 139                 skbmod_usage();
 140         }
 141
 142         tail = addattr_nest(n, MAX_MSG, tca_id);
 143         addattr_l(n, MAX_MSG, TCA_SKBMOD_PARMS, &p, sizeof(p));
 144
 145         if (daddr)
 146                 addattr_l(n, MAX_MSG, TCA_SKBMOD_DMAC, dbuf, ETH_ALEN);
 147         if (skbmod_etype)
 148                 addattr16(n, MAX_MSG, TCA_SKBMOD_ETYPE, skbmod_etype);
 149         if (saddr)
 150                 addattr_l(n, MAX_MSG, TCA_SKBMOD_SMAC, sbuf, ETH_ALEN);
 151
 152         addattr_nest_end(n, tail);
 153
 154         *argc_p = argc;
 155         *argv_p = argv;
 156         return 0;
 157 }
 158
 159 static int print_skbmod(const struct action_util *au, FILE *f, struct rtattr *arg)
 160 {
 161         struct tc_skbmod *p;
 162         struct rtattr *tb[TCA_SKBMOD_MAX + 1];
 163         __u16 skbmod_etype = 0;
 164         int has_optional = 0;
 165         SPRINT_BUF(b1);
 166         SPRINT_BUF(b2);
 167
 168         if (arg == NULL)
 169                 return 0;
 170
 171         parse_rtattr_nested(tb, TCA_SKBMOD_MAX, arg);
 172
 173         if (tb[TCA_SKBMOD_PARMS] == NULL) {
 174                 fprintf(stderr, "Missing skbmod parameters\n");
 175                 return -1;
 176         }
 177
 178         p = RTA_DATA(tb[TCA_SKBMOD_PARMS]);
 179
 180         fprintf(f, "skbmod ");
 181         print_action_control(f, "", p->action, " ");
 182
 183         if (tb[TCA_SKBMOD_ETYPE]) {
 184                 skbmod_etype = rta_getattr_u16(tb[TCA_SKBMOD_ETYPE]);
 185                 has_optional = 1;
 186                 fprintf(f, "set etype 0x%X ", skbmod_etype);
 187         }
 188
 189         if (has_optional)
 190                 fprintf(f, "\n\t ");
 191
 192         if (tb[TCA_SKBMOD_DMAC]) {
 193                 has_optional = 1;
 194                 fprintf(f, "set dmac %s ",
 195                         ll_addr_n2a(RTA_DATA(tb[TCA_SKBMOD_DMAC]),
 196                                     RTA_PAYLOAD(tb[TCA_SKBMOD_DMAC]), 0, b1,
 197                                     sizeof(b1)));
 198
 199         }
 200
 201         if (tb[TCA_SKBMOD_SMAC]) {
 202                 has_optional = 1;
 203                 fprintf(f, "set smac %s ",
 204                         ll_addr_n2a(RTA_DATA(tb[TCA_SKBMOD_SMAC]),
 205                                     RTA_PAYLOAD(tb[TCA_SKBMOD_SMAC]), 0, b2,
 206                                     sizeof(b2)));
 207         }
 208
 209         if (p->flags & SKBMOD_F_SWAPMAC)
 210                 fprintf(f, "swap mac ");
 211
 212         if (p->flags & SKBMOD_F_ECN)
 213                 fprintf(f, "ecn ");
 214
 215         fprintf(f, "\n\t index %u ref %d bind %d", p->index, p->refcnt,
 216                 p->bindcnt);
 217         if (show_stats) {
 218                 if (tb[TCA_SKBMOD_TM]) {
 219                         struct tcf_t *tm = RTA_DATA(tb[TCA_SKBMOD_TM]);
 220
 221                         print_tm(f, tm);
 222                 }
 223         }
 224
 225         fprintf(f, "\n");
 226
 227         return 0;
 228 }
 229
 230 struct action_util skbmod_action_util = {
 231         .id = "skbmod",
 232         .parse_aopt = parse_skbmod,
 233         .print_aopt = print_skbmod,
 234 };