dist/ipf/lib/ipft_tx.c

   1 /*      $NetBSD: ipft_tx.c,v 1.7 2007/04/14 20:34:28 martin Exp $       */
   2
   3 /*
   4  * Copyright (C) 2000-2006 by Darren Reed.
   5  *
   6  * See the IPFILTER.LICENCE file for details on licencing.
   7  *
   8  * Id: ipft_tx.c,v 1.15.2.10 2007/09/03 21:54:44 darrenr Exp
   9  */
  10 #if !defined(lint)
  11 static const char sccsid[] = "@(#)ipft_tx.c     1.7 6/5/96 (C) 1993 Darren Reed";
  12 static const char rcsid[] = "@(#)Id: ipft_tx.c,v 1.15.2.10 2007/09/03 21:54:44 darrenr Exp";
  13 #endif
  14
  15 #include <ctype.h>
  16
  17 #include "ipf.h"
  18 #include "ipt.h"
  19
  20 #ifndef linux
  21 #include <netinet/ip_var.h>
  22 #endif
  23 #include <netinet/tcpip.h>
  24
  25
  26 extern  int     opts;
  27
  28 static  char    *tx_proto = "";
  29
  30 static  int     text_open __P((char *)), text_close __P((void));
  31 static  int     text_readip __P((char *, int, char **, int *));
  32 static  int     parseline __P((char *, ip_t *, char **, int *));
  33
  34 static  char    myflagset[] = "FSRPAUEC";
  35 static  u_char  myflags[] = { TH_FIN, TH_SYN, TH_RST, TH_PUSH,
  36                                 TH_ACK, TH_URG, TH_ECN, TH_CWR };
  37
  38 struct  ipread  iptext = { text_open, text_close, text_readip, R_DO_CKSUM };
  39 static  FILE    *tfp = NULL;
  40 static  int     tfd = -1;
  41
  42 static  u_32_t  tx_hostnum __P((char *, int *));
  43 static  u_short tx_portnum __P((char *));
  44
  45
  46 /*
  47  * returns an ip address as a long var as a result of either a DNS lookup or
  48  * straight inet_addr() call
  49  */
  50 static  u_32_t  tx_hostnum(host, resolved)
  51 char    *host;
  52 int     *resolved;
  53 {
  54         u_32_t  ipa;
  55
  56         *resolved = 0;
  57         if (!strcasecmp("any", host))
  58                 return 0L;
  59         if (ISDIGIT(*host))
  60                 return inet_addr(host);
  61
  62         if (gethost(host, &ipa) == -1) {
  63                 *resolved = -1;
  64                 fprintf(stderr, "can't resolve hostname: %s\n", host);
  65                 return 0;
  66         }
  67         return ipa;
  68 }
  69
  70
  71 /*
  72  * find the port number given by the name, either from getservbyname() or
  73  * straight atoi()
  74  */
  75 static  u_short tx_portnum(name)
  76 char    *name;
  77 {
  78         struct  servent *sp;
  79
  80         if (ISDIGIT(*name))
  81                 return (u_short)atoi(name);
  82         sp = getservbyname(name, tx_proto);
  83         if (sp)
  84                 return ntohs(sp->s_port);
  85         (void) fprintf(stderr, "unknown service \"%s\".\n", name);
  86         return 0;
  87 }
  88
  89
  90 char    *tx_icmptypes[] = {
  91         "echorep", (char *)NULL, (char *)NULL, "unreach", "squench",
  92         "redir", (char *)NULL, (char *)NULL, "echo", "routerad",
  93         "routersol", "timex", "paramprob", "timest", "timestrep",
  94         "inforeq", "inforep", "maskreq", "maskrep", "END"
  95 };
  96
  97 static  int     text_open(fname)
  98 char    *fname;
  99 {
 100         if (tfp && tfd != -1) {
 101                 rewind(tfp);
 102                 return tfd;
 103         }
 104
 105         if (!strcmp(fname, "-")) {
 106                 tfd = 0;
 107                 tfp = stdin;
 108         } else {
 109                 tfd = open(fname, O_RDONLY);
 110                 if (tfd != -1)
 111                         tfp = fdopen(tfd, "r");
 112         }
 113         return tfd;
 114 }
 115
 116
 117 static  int     text_close()
 118 {
 119         int     cfd = tfd;
 120
 121         tfd = -1;
 122         return close(cfd);
 123 }
 124
 125
 126 static  int     text_readip(buf, cnt, ifn, dir)
 127 char    *buf, **ifn;
 128 int     cnt, *dir;
 129 {
 130         register char *s;
 131         char    line[513];
 132         ip_t    *ip;
 133
 134         *ifn = NULL;
 135         while (fgets(line, sizeof(line)-1, tfp)) {
 136                 if ((s = strchr(line, '\n')))
 137                         *s = '\0';
 138                 if ((s = strchr(line, '\r')))
 139                         *s = '\0';
 140                 if ((s = strchr(line, '#')))
 141                         *s = '\0';
 142                 if (!*line)
 143                         continue;
 144                 if ((opts & OPT_DEBUG) != 0)
 145                         printf("input: %s\n", line);
 146                 *ifn = NULL;
 147                 *dir = 0;
 148                 if (!parseline(line, (ip_t *)buf, ifn, dir)) {
 149                         ip = (ip_t *)buf;
 150                         return ntohs(ip->ip_len);
 151                 }
 152         }
 153         if (feof(tfp))
 154                 return 0;
 155         return -1;
 156 }
 157
 158 static  int     parseline(line, ip, ifn, out)
 159 char    *line;
 160 ip_t    *ip;
 161 char    **ifn;
 162 int     *out;
 163 {
 164         tcphdr_t        th, *tcp = &th;
 165         struct  icmp    icmp, *ic = &icmp;
 166         char    *cps[20], **cpp, c, ipopts[68];
 167         int     i, r;
 168
 169         if (*ifn)
 170                 free(*ifn);
 171         bzero((char *)ip, MAX(sizeof(*tcp), sizeof(*ic)) + sizeof(*ip));
 172         bzero((char *)tcp, sizeof(*tcp));
 173         bzero((char *)ic, sizeof(*ic));
 174         bzero(ipopts, sizeof(ipopts));
 175         IP_HL_A(ip, sizeof(*ip) >> 2);
 176         IP_V_A(ip, IPVERSION);
 177         for (i = 0, cps[0] = strtok(line, " \b\t\r\n"); cps[i] && i < 19; )
 178                 cps[++i] = strtok(NULL, " \b\t\r\n");
 179
 180         cpp = cps;
 181         if (!*cpp)
 182                 return 1;
 183
 184         c = **cpp;
 185         if (!ISALPHA(c) || (TOLOWER(c) != 'o' && TOLOWER(c) != 'i')) {
 186                 fprintf(stderr, "bad direction \"%s\"\n", *cpp);
 187                 return 1;
 188         }
 189         *out = (TOLOWER(c) == 'o') ? 1 : 0;
 190         cpp++;
 191         if (!*cpp)
 192                 return 1;
 193
 194         if (!strcasecmp(*cpp, "on")) {
 195                 cpp++;
 196                 if (!*cpp)
 197                         return 1;
 198                 *ifn = strdup(*cpp++);
 199                 if (!*cpp)
 200                         return 1;
 201         }
 202
 203         c = **cpp;
 204         ip->ip_len = sizeof(ip_t);
 205         if (!strcasecmp(*cpp, "tcp") || !strcasecmp(*cpp, "udp") ||
 206             !strcasecmp(*cpp, "icmp")) {
 207                 if (c == 't') {
 208                         ip->ip_p = IPPROTO_TCP;
 209                         ip->ip_len += sizeof(struct tcphdr);
 210                         tx_proto = "tcp";
 211                 } else if (c == 'u') {
 212                         ip->ip_p = IPPROTO_UDP;
 213                         ip->ip_len += sizeof(struct udphdr);
 214                         tx_proto = "udp";
 215                 } else {
 216                         ip->ip_p = IPPROTO_ICMP;
 217                         ip->ip_len += ICMPERR_IPICMPHLEN;
 218                         tx_proto = "icmp";
 219                 }
 220                 cpp++;
 221         } else if (ISDIGIT(**cpp) && !index(*cpp, '.')) {
 222                 ip->ip_p = atoi(*cpp);
 223                 cpp++;
 224         } else
 225                 ip->ip_p = IPPROTO_IP;
 226
 227         if (!*cpp)
 228                 return 1;
 229         if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP) {
 230                 char    *last;
 231
 232                 last = strchr(*cpp, ',');
 233                 if (!last) {
 234                         fprintf(stderr, "tcp/udp with no source port\n");
 235                         return 1;
 236                 }
 237                 *last++ = '\0';
 238                 tcp->th_sport = htons(tx_portnum(last));
 239                 if (ip->ip_p == IPPROTO_TCP) {
 240                         tcp->th_win = htons(4096);
 241                         TCP_OFF_A(tcp, sizeof(*tcp) >> 2);
 242                 }
 243         }
 244         ip->ip_src.s_addr = tx_hostnum(*cpp, &r);
 245         cpp++;
 246         if (!*cpp)
 247                 return 1;
 248
 249         if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP) {
 250                 char    *last;
 251
 252                 last = strchr(*cpp, ',');
 253                 if (!last) {
 254                         fprintf(stderr, "tcp/udp with no destination port\n");
 255                         return 1;
 256                 }
 257                 *last++ = '\0';
 258                 tcp->th_dport = htons(tx_portnum(last));
 259         }
 260         ip->ip_dst.s_addr = tx_hostnum(*cpp, &r);
 261         cpp++;
 262         if (ip->ip_p == IPPROTO_TCP) {
 263                 if (*cpp != NULL) {
 264                         char    *s, *t;
 265
 266                         tcp->th_flags = 0;
 267                         for (s = *cpp; *s; s++)
 268                                 if ((t  = strchr(myflagset, *s)))
 269                                         tcp->th_flags |= myflags[t-myflagset];
 270                         if (tcp->th_flags)
 271                                 cpp++;
 272                 }
 273
 274                 if (tcp->th_flags & TH_URG)
 275                         tcp->th_urp = htons(1);
 276
 277                 if (*cpp && !strncasecmp(*cpp, "seq=", 4)) {
 278                         tcp->th_seq = htonl(atoi(*cpp + 4));
 279                         cpp++;
 280                 }
 281
 282                 if (*cpp && !strncasecmp(*cpp, "ack=", 4)) {
 283                         tcp->th_ack = htonl(atoi(*cpp + 4));
 284                         cpp++;
 285                 }
 286         } else if (*cpp && ip->ip_p == IPPROTO_ICMP) {
 287                 extern  char    *tx_icmptypes[];
 288                 char    **s, *t;
 289                 int     i;
 290
 291                 t = strchr(*cpp, ',');
 292                 if (t != NULL)
 293                         *t = '\0';
 294
 295                 for (s = tx_icmptypes, i = 0; !*s || strcmp(*s, "END");
 296                      s++, i++) {
 297                         if (*s && !strcasecmp(*cpp, *s)) {
 298                                 ic->icmp_type = i;
 299                                 if (t != NULL)
 300                                         ic->icmp_code = atoi(t + 1);
 301                                 cpp++;
 302                                 break;
 303                         }
 304                 }
 305                 if (t != NULL)
 306                         *t = ',';
 307         }
 308
 309         if (*cpp && !strcasecmp(*cpp, "opt")) {
 310                 u_long  olen;
 311
 312                 cpp++;
 313                 olen = buildopts(*cpp, ipopts, (IP_HL(ip) - 5) << 2);
 314                 if (olen) {
 315                         bcopy(ipopts, (char *)(ip + 1), olen);
 316                         IP_HL_A(ip, IP_HL(ip) + (olen >> 2));
 317                 }
 318         }
 319         if (ip->ip_p == IPPROTO_TCP || ip->ip_p == IPPROTO_UDP)
 320                 bcopy((char *)tcp, ((char *)ip) + (IP_HL(ip) << 2),
 321                         sizeof(*tcp));
 322         else if (ip->ip_p == IPPROTO_ICMP)
 323                 bcopy((char *)ic, ((char *)ip) + (IP_HL(ip) << 2),
 324                         sizeof(*ic));
 325         ip->ip_len = htons(ip->ip_len);
 326         return 0;
 327 }