tc/m_csum.c

   1 /*
   2  * m_csum.c     checksum updating action
   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: Gregoire Baron <baronchon@n7mm.org>
  10  */
  11
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <unistd.h>
  16
  17 #include <linux/tc_act/tc_csum.h>
  18
  19 #include "utils.h"
  20 #include "tc_util.h"
  21
  22 static void
  23 explain(void)
  24 {
  25         fprintf(stderr, "Usage: ... csum <UPDATE>\n"
  26                         "Where: UPDATE := <TARGET> [<UPDATE>]\n"
  27                         "       TARGET := { ip4h | icmp | igmp |"
  28                                 " tcp | udp | udplite | <SWEETS> }\n"
  29                         "       SWEETS := { and | or | \'+\' }\n");
  30 }
  31
  32 static void
  33 usage(void)
  34 {
  35         explain();
  36         exit(-1);
  37 }
  38
  39 static int
  40 parse_csum_args(int *argc_p, char ***argv_p, struct tc_csum *sel)
  41 {
  42         int argc = *argc_p;
  43         char **argv = *argv_p;
  44
  45         if (argc <= 0)
  46                 return -1;
  47
  48         while(argc > 0) {
  49                 if ((matches(*argv, "iph") == 0) ||
  50                     (matches(*argv, "ip4h") == 0) ||
  51                     (matches(*argv, "ipv4h") == 0))
  52                         sel->update_flags |= TCA_CSUM_UPDATE_FLAG_IPV4HDR;
  53
  54                 else if (matches(*argv, "icmp") == 0)
  55                         sel->update_flags |= TCA_CSUM_UPDATE_FLAG_ICMP;
  56
  57                 else if (matches(*argv, "igmp") == 0)
  58                         sel->update_flags |= TCA_CSUM_UPDATE_FLAG_IGMP;
  59
  60                 else if (matches(*argv, "tcp") == 0)
  61                         sel->update_flags |= TCA_CSUM_UPDATE_FLAG_TCP;
  62
  63                 else if (matches(*argv, "udp") == 0)
  64                         sel->update_flags |= TCA_CSUM_UPDATE_FLAG_UDP;
  65
  66                 else if (matches(*argv, "udplite") == 0)
  67                         sel->update_flags |= TCA_CSUM_UPDATE_FLAG_UDPLITE;
  68
  69                 else if ((matches(*argv, "and") == 0) ||
  70                          (matches(*argv, "or") == 0) ||
  71                          (matches(*argv, "+") == 0))
  72                         ; /* just ignore: ... csum iph and tcp or udp */
  73                 else
  74                         break;
  75                 argc--;
  76                 argv++;
  77         }
  78
  79         *argc_p = argc;
  80         *argv_p = argv;
  81
  82         return 0;
  83 }
  84
  85 static int
  86 parse_csum(struct action_util *a, int *argc_p,
  87            char ***argv_p, int tca_id, struct nlmsghdr *n)
  88 {
  89         struct tc_csum sel;
  90
  91         int argc = *argc_p;
  92         char **argv = *argv_p;
  93         int ok = 0;
  94         struct rtattr *tail;
  95
  96         memset(&sel, 0, sizeof(sel));
  97
  98         while (argc > 0) {
  99                 if (matches(*argv, "csum") == 0) {
 100                         NEXT_ARG();
 101                         if (parse_csum_args(&argc, &argv, &sel)) {
 102                                 fprintf(stderr, "Illegal csum construct (%s)\n",
 103                                         *argv);
 104                                 explain();
 105                                 return -1;
 106                         }
 107                         ok++;
 108                         continue;
 109                 } else if (matches(*argv, "help") == 0) {
 110                         usage();
 111                 }
 112                 else {
 113                         break;
 114                 }
 115         }
 116
 117         if (!ok) {
 118                 explain();
 119                 return -1;
 120         }
 121
 122         if (sel.update_flags == 0) {
 123                 fprintf(stderr, "Illegal csum construct, empty <UPDATE> list\n");
 124                 return -1;
 125         }
 126
 127         if (argc) {
 128                 if (matches(*argv, "reclassify") == 0) {
 129                         sel.action = TC_ACT_RECLASSIFY;
 130                         argc--;
 131                         argv++;
 132                 } else if (matches(*argv, "pipe") == 0) {
 133                         sel.action = TC_ACT_PIPE;
 134                         argc--;
 135                         argv++;
 136                 } else if (matches(*argv, "drop") == 0 ||
 137                         matches(*argv, "shot") == 0) {
 138                         sel.action = TC_ACT_SHOT;
 139                         argc--;
 140                         argv++;
 141                 } else if (matches(*argv, "continue") == 0) {
 142                         sel.action = TC_ACT_UNSPEC;
 143                         argc--;
 144                         argv++;
 145                 } else if (matches(*argv, "pass") == 0) {
 146                         sel.action = TC_ACT_OK;
 147                         argc--;
 148                         argv++;
 149                 }
 150         }
 151
 152         if (argc) {
 153                 if (matches(*argv, "index") == 0) {
 154                         NEXT_ARG();
 155                         if (get_u32(&sel.index, *argv, 10)) {
 156                                 fprintf(stderr, "Illegal \"index\" (%s) <csum>\n",
 157                                         *argv);
 158                                 return -1;
 159                         }
 160                         argc--;
 161                         argv++;
 162                 }
 163         }
 164
 165         tail = NLMSG_TAIL(n);
 166         addattr_l(n, MAX_MSG, tca_id, NULL, 0);
 167         addattr_l(n, MAX_MSG, TCA_CSUM_PARMS, &sel, sizeof(sel));
 168         tail->rta_len = (char *)NLMSG_TAIL(n) - (char *)tail;
 169
 170         *argc_p = argc;
 171         *argv_p = argv;
 172
 173         return 0;
 174 }
 175
 176 static int
 177 print_csum(struct action_util *au, FILE * f, struct rtattr *arg)
 178 {
 179         struct tc_csum *sel;
 180
 181         struct rtattr *tb[TCA_CSUM_MAX + 1];
 182
 183         char *uflag_1 = "";
 184         char *uflag_2 = "";
 185         char *uflag_3 = "";
 186         char *uflag_4 = "";
 187         char *uflag_5 = "";
 188         char *uflag_6 = "";
 189         SPRINT_BUF(action_buf);
 190
 191         int uflag_count = 0;
 192
 193         if (arg == NULL)
 194                 return -1;
 195
 196         parse_rtattr_nested(tb, TCA_CSUM_MAX, arg);
 197
 198         if (tb[TCA_CSUM_PARMS] == NULL) {
 199                 fprintf(f, "[NULL csum parameters]");
 200                 return -1;
 201         }
 202         sel = RTA_DATA(tb[TCA_CSUM_PARMS]);
 203
 204         if (sel->update_flags & TCA_CSUM_UPDATE_FLAG_IPV4HDR) {
 205                 uflag_1 = "iph";
 206                 uflag_count++;
 207         }
 208         #define CSUM_UFLAG_BUFFER(flag_buffer, flag_value, flag_string) \
 209                 do {                                                    \
 210                         if (sel->update_flags & flag_value) {           \
 211                                 flag_buffer = uflag_count > 0 ?         \
 212                                         ", " flag_string : flag_string; \
 213                                 uflag_count++;                          \
 214                         }                                               \
 215                 } while(0)
 216         CSUM_UFLAG_BUFFER(uflag_2, TCA_CSUM_UPDATE_FLAG_ICMP, "icmp");
 217         CSUM_UFLAG_BUFFER(uflag_3, TCA_CSUM_UPDATE_FLAG_IGMP, "igmp");
 218         CSUM_UFLAG_BUFFER(uflag_4, TCA_CSUM_UPDATE_FLAG_TCP, "tdp");
 219         CSUM_UFLAG_BUFFER(uflag_5, TCA_CSUM_UPDATE_FLAG_UDP, "udp");
 220         CSUM_UFLAG_BUFFER(uflag_6, TCA_CSUM_UPDATE_FLAG_UDPLITE, "udplite");
 221         if (!uflag_count) {
 222                 uflag_1 = "?empty";
 223         }
 224
 225         fprintf(f, "csum (%s%s%s%s%s%s) action %s\n",
 226                 uflag_1, uflag_2, uflag_3,
 227                 uflag_4, uflag_5, uflag_6,
 228                 action_n2a(sel->action, action_buf, sizeof(action_buf)));
 229         fprintf(f, "\tindex %d ref %d bind %d", sel->index, sel->refcnt, sel->bindcnt);
 230
 231         if (show_stats) {
 232                 if (tb[TCA_CSUM_TM]) {
 233                         struct tcf_t *tm = RTA_DATA(tb[TCA_CSUM_TM]);
 234                         print_tm(f,tm);
 235                 }
 236         }
 237         fprintf(f, "\n");
 238
 239         return 0;
 240 }
 241
 242 struct action_util csum_action_util = {
 243         .id = "csum",
 244         .parse_aopt = parse_csum,
 245         .print_aopt = print_csum,
 246 };