tc/m_skbmod.c

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