/* * Copyright (C) 1993-2002 by Darren Reed. * * See the IPFILTER.LICENCE file for details on licencing. */ #if defined(__sgi) && (IRIX > 602) # include #endif #include #include #include #include #include #if !defined(__SVR4) && !defined(__svr4__) # include #else # include #endif #include #include #include #include #include #include #include #if defined(sun) && (defined(__svr4__) || defined(__SVR4)) # include # include #endif #include #include #include #include #include #if __FreeBSD_version >= 300000 # include #endif #include #include #include #include #include #include "netinet/ip_compat.h" #include "netinet/ip_fil.h" #include "netinet/ip_nat.h" #include "netinet/ip_state.h" #include "netinet/ip_proxy.h" #include "ipf.h" #if defined(sun) && !SOLARIS2 # define STRERROR(x) sys_errlist[x] extern char *sys_errlist[]; #else # define STRERROR(x) strerror(x) #endif #if !defined(lint) static const char sccsid[] ="@(#)ipnat.c 1.9 6/5/96 (C) 1993 Darren Reed"; static const char rcsid[] = "@(#)$Id: natparse.c,v 1.17.2.27 2002/12/06 11:40:27 darrenr Exp $"; #endif #if SOLARIS #define bzero(a,b) memset(a,0,b) #endif extern void printnat __P((ipnat_t *, int)); extern int countbits __P((u_32_t)); extern char *proto; ipnat_t *natparse __P((char *, int)); void natparsefile __P((int, char *, int)); void nat_setgroupmap __P((struct ipnat *)); void nat_setgroupmap(n) ipnat_t *n; { if (n->in_outmsk == n->in_inmsk) n->in_ippip = 1; else if (n->in_flags & IPN_AUTOPORTMAP) { n->in_ippip = ~ntohl(n->in_inmsk); if (n->in_outmsk != 0xffffffff) n->in_ippip /= (~ntohl(n->in_outmsk) + 1); n->in_ippip++; if (n->in_ippip == 0) n->in_ippip = 1; n->in_ppip = USABLE_PORTS / n->in_ippip; } else { n->in_space = USABLE_PORTS * ~ntohl(n->in_outmsk); n->in_nip = 0; if (!(n->in_ppip = n->in_pmin)) n->in_ppip = 1; n->in_ippip = USABLE_PORTS / n->in_ppip; } } /* * Parse a line of input from the ipnat configuration file */ ipnat_t *natparse(line, linenum) char *line; int linenum; { static ipnat_t ipn; struct protoent *pr; char *dnetm = NULL, *dport = NULL; char *s, *t, *cps[31], **cpp; int i, cnt; char *port1a = NULL, *port1b = NULL, *port2a = NULL; proto = NULL; /* * Search for end of line and comment marker, advance of leading spaces */ if ((s = strchr(line, '\n'))) *s = '\0'; if ((s = strchr(line, '#'))) *s = '\0'; while (*line && isspace(*line)) line++; if (!*line) return NULL; bzero((char *)&ipn, sizeof(ipn)); cnt = 0; /* * split line upto into segments. */ for (i = 0, *cps = strtok(line, " \b\t\r\n"); cps[i] && i < 30; cnt++) cps[++i] = strtok(NULL, " \b\t\r\n"); cps[i] = NULL; if (cnt < 3) { fprintf(stderr, "%d: not enough segments in line\n", linenum); return NULL; } cpp = cps; /* * Check first word is a recognised keyword and then is the interface */ if (!strcasecmp(*cpp, "map")) ipn.in_redir = NAT_MAP; else if (!strcasecmp(*cpp, "map-block")) ipn.in_redir = NAT_MAPBLK; else if (!strcasecmp(*cpp, "rdr")) ipn.in_redir = NAT_REDIRECT; else if (!strcasecmp(*cpp, "bimap")) ipn.in_redir = NAT_BIMAP; else { fprintf(stderr, "%d: unknown mapping: \"%s\"\n", linenum, *cpp); return NULL; } cpp++; strncpy(ipn.in_ifname, *cpp, sizeof(ipn.in_ifname) - 1); ipn.in_ifname[sizeof(ipn.in_ifname) - 1] = '\0'; cpp++; /* * If the first word after the interface is "from" or is a ! then * the expanded syntax is being used so parse it differently. */ if (!strcasecmp(*cpp, "from") || (**cpp == '!')) { if (!strcmp(*cpp, "!")) { cpp++; if (strcasecmp(*cpp, "from")) { fprintf(stderr, "Missing from after !\n"); return NULL; } ipn.in_flags |= IPN_NOTSRC; } else if (**cpp == '!') { if (strcasecmp(*cpp + 1, "from")) { fprintf(stderr, "Missing from after !\n"); return NULL; } ipn.in_flags |= IPN_NOTSRC; } if ((ipn.in_flags & IPN_NOTSRC) && (ipn.in_redir & (NAT_MAP|NAT_MAPBLK))) { fprintf(stderr, "Cannot use '! from' with map\n"); return NULL; } ipn.in_flags |= IPN_FILTER; cpp++; if (ipn.in_redir == NAT_REDIRECT) { if (hostmask(&cpp, (u_32_t *)&ipn.in_srcip, (u_32_t *)&ipn.in_srcmsk, &ipn.in_sport, &ipn.in_scmp, &ipn.in_stop, linenum)) { return NULL; } } else { if (hostmask(&cpp, (u_32_t *)&ipn.in_inip, (u_32_t *)&ipn.in_inmsk, &ipn.in_sport, &ipn.in_scmp, &ipn.in_stop, linenum)) { return NULL; } } if (!strcmp(*cpp, "!")) { cpp++; ipn.in_flags |= IPN_NOTDST; } else if (**cpp == '!') { (*cpp)++; ipn.in_flags |= IPN_NOTDST; } if (strcasecmp(*cpp, "to")) { fprintf(stderr, "%d: unexpected keyword (%s) - to\n", linenum, *cpp); return NULL; } if ((ipn.in_flags & IPN_NOTDST) && (ipn.in_redir & (NAT_REDIRECT))) { fprintf(stderr, "Cannot use '! to' with rdr\n"); return NULL; } if (!*++cpp) { fprintf(stderr, "%d: missing host after to\n", linenum); return NULL; } if (ipn.in_redir == NAT_REDIRECT) { if (hostmask(&cpp, (u_32_t *)&ipn.in_outip, (u_32_t *)&ipn.in_outmsk, &ipn.in_dport, &ipn.in_dcmp, &ipn.in_dtop, linenum)) { return NULL; } ipn.in_pmin = htons(ipn.in_dport); } else { if (hostmask(&cpp, (u_32_t *)&ipn.in_srcip, (u_32_t *)&ipn.in_srcmsk, &ipn.in_dport, &ipn.in_dcmp, &ipn.in_dtop, linenum)) { return NULL; } } } else { s = *cpp; if (!s) { fprintf(stderr, "%d: short line\n", linenum); return NULL; } t = strchr(s, '/'); if (!t) { fprintf(stderr, "%d: no netmask on LHS\n", linenum); return NULL; } *t++ = '\0'; if (ipn.in_redir == NAT_REDIRECT) { if (hostnum((u_32_t *)&ipn.in_outip, s, linenum) == -1) return NULL; if (genmask(t, (u_32_t *)&ipn.in_outmsk) == -1) { return NULL; } } else { if (hostnum((u_32_t *)&ipn.in_inip, s, linenum) == -1) return NULL; if (genmask(t, (u_32_t *)&ipn.in_inmsk) == -1) { return NULL; } } cpp++; if (!*cpp) { fprintf(stderr, "%d: short line\n", linenum); return NULL; } } /* * If it is a standard redirect then we expect it to have a port * match after the hostmask. */ if ((ipn.in_redir == NAT_REDIRECT) && !(ipn.in_flags & IPN_FILTER)) { if (strcasecmp(*cpp, "port")) { fprintf(stderr, "%d: missing fields - 1st port\n", linenum); return NULL; } cpp++; if (!*cpp) { fprintf(stderr, "%d: missing fields (destination port)\n", linenum); return NULL; } if (isdigit(**cpp) && (s = strchr(*cpp, '-'))) *s++ = '\0'; else s = NULL; port1a = *cpp++; if (!strcmp(*cpp, "-")) { cpp++; s = *cpp++; } if (s) port1b = s; else ipn.in_pmax = ipn.in_pmin; } /* * In the middle of the NAT rule syntax is -> to indicate the * direction of translation. */ if (!*cpp) { fprintf(stderr, "%d: missing fields (->)\n", linenum); return NULL; } if (strcmp(*cpp, "->")) { fprintf(stderr, "%d: missing ->\n", linenum); return NULL; } cpp++; if (!*cpp) { fprintf(stderr, "%d: missing fields (%s)\n", linenum, ipn.in_redir ? "destination" : "target"); return NULL; } if (ipn.in_redir == NAT_MAP) { if (!strcasecmp(*cpp, "range")) { cpp++; ipn.in_flags |= IPN_IPRANGE; if (!*cpp) { fprintf(stderr, "%d: missing fields (%s)\n", linenum, ipn.in_redir ? "destination":"target"); return NULL; } } } if (ipn.in_flags & IPN_IPRANGE) { dnetm = strrchr(*cpp, '-'); if (dnetm == NULL) { cpp++; if (*cpp && !strcmp(*cpp, "-") && *(cpp + 1)) dnetm = *(cpp + 1); } else *dnetm++ = '\0'; if (dnetm == NULL || *dnetm == '\0') { fprintf(stderr, "%d: desination range not specified\n", linenum); return NULL; } } else if (ipn.in_redir != NAT_REDIRECT) { dnetm = strrchr(*cpp, '/'); if (dnetm == NULL) { cpp++; if (*cpp && !strcasecmp(*cpp, "netmask")) dnetm = *++cpp; } if (dnetm == NULL) { fprintf(stderr, "%d: missing fields (dest netmask)\n", linenum); return NULL; } if (*dnetm == '/') *dnetm++ = '\0'; } if (ipn.in_redir == NAT_REDIRECT) { dnetm = strchr(*cpp, ','); if (dnetm != NULL) { ipn.in_flags |= IPN_SPLIT; *dnetm++ = '\0'; } if (hostnum((u_32_t *)&ipn.in_inip, *cpp, linenum) == -1) return NULL; #if SOLARIS if (ntohl(ipn.in_inip) == INADDR_LOOPBACK) { fprintf(stderr, "localhost as destination not supported\n"); return NULL; } #endif } else { if (!strcmp(*cpp, ipn.in_ifname)) *cpp = "0"; if (hostnum((u_32_t *)&ipn.in_outip, *cpp, linenum) == -1) return NULL; } cpp++; if (ipn.in_redir & NAT_MAPBLK) { if (*cpp) { if (strcasecmp(*cpp, "ports")) { fprintf(stderr, "%d: expected \"ports\" - got \"%s\"\n", linenum, *cpp); return NULL; } cpp++; if (*cpp == NULL) { fprintf(stderr, "%d: missing argument to \"ports\"\n", linenum); return NULL; } if (!strcasecmp(*cpp, "auto")) ipn.in_flags |= IPN_AUTOPORTMAP; else ipn.in_pmin = atoi(*cpp); cpp++; } else ipn.in_pmin = 0; } else if ((ipn.in_redir & NAT_BIMAP) == NAT_REDIRECT) { if (*cpp && (strrchr(*cpp, '/') != NULL)) { fprintf(stderr, "%d: No netmask supported in %s\n", linenum, "destination host for redirect"); return NULL; } if (!*cpp) { fprintf(stderr, "%d: Missing destination port %s\n", linenum, "in redirect"); return NULL; } /* If it's a in_redir, expect target port */ if (strcasecmp(*cpp, "port")) { fprintf(stderr, "%d: missing fields - 2nd port (%s)\n", linenum, *cpp); return NULL; } cpp++; if (!*cpp) { fprintf(stderr, "%d: missing fields (destination port)\n", linenum); return NULL; } port2a = *cpp++; } if (dnetm && *dnetm == '/') *dnetm++ = '\0'; if (ipn.in_redir & (NAT_MAP|NAT_MAPBLK)) { if (ipn.in_flags & IPN_IPRANGE) { if (hostnum((u_32_t *)&ipn.in_outmsk, dnetm, linenum) == -1) return NULL; } else if (genmask(dnetm, (u_32_t *)&ipn.in_outmsk)) return NULL; } else { if (ipn.in_flags & IPN_SPLIT) { if (hostnum((u_32_t *)&ipn.in_inmsk, dnetm, linenum) == -1) return NULL; } else if (genmask("255.255.255.255", (u_32_t *)&ipn.in_inmsk)) return NULL; if (!*cpp) { ipn.in_flags |= IPN_TCP; /* XXX- TCP only by default */ proto = "tcp"; } else { proto = *cpp++; if (!strcasecmp(proto, "tcp")) ipn.in_flags |= IPN_TCP; else if (!strcasecmp(proto, "udp")) ipn.in_flags |= IPN_UDP; else if (!strcasecmp(proto, "tcp/udp")) ipn.in_flags |= IPN_TCPUDP; else if (!strcasecmp(proto, "tcpudp")) { ipn.in_flags |= IPN_TCPUDP; proto = "tcp/udp"; } else if (!strcasecmp(proto, "ip")) ipn.in_flags |= IPN_ANY; else { ipn.in_flags |= IPN_ANY; if ((pr = getprotobyname(proto))) ipn.in_p = pr->p_proto; else { if (!isdigit(*proto)) { fprintf(stderr, "%d: Unknown protocol %s\n", linenum, proto); return NULL; } else ipn.in_p = atoi(proto); } } if ((ipn.in_flags & IPN_TCPUDP) == 0) { port1a = "0"; port2a = "0"; } if (*cpp && !strcasecmp(*cpp, "round-robin")) { cpp++; ipn.in_flags |= IPN_ROUNDR; } if (*cpp && !strcasecmp(*cpp, "frag")) { cpp++; ipn.in_flags |= IPN_FRAG; } if (*cpp && !strcasecmp(*cpp, "age")) { cpp++; if (!*cpp) { fprintf(stderr, "%d: age with no parameters\n", linenum); return NULL; } ipn.in_age[0] = atoi(*cpp); s = index(*cpp, '/'); if (s != NULL) ipn.in_age[1] = atoi(s + 1); else ipn.in_age[1] = ipn.in_age[0]; cpp++; } if (*cpp && !strcasecmp(*cpp, "mssclamp")) { cpp++; if (*cpp) { ipn.in_mssclamp = atoi(*cpp); cpp++; } else { fprintf(stderr, "%d: mssclamp with no parameters\n", linenum); return NULL; } } if (*cpp) { fprintf(stderr, "%d: extra junk at the end of the line: %s\n", linenum, *cpp); return NULL; } } } if ((ipn.in_redir == NAT_REDIRECT) && !(ipn.in_flags & IPN_FILTER)) { if (!portnum(port1a, &ipn.in_pmin, linenum)) return NULL; ipn.in_pmin = htons(ipn.in_pmin); if (port1b != NULL) { if (!portnum(port1b, &ipn.in_pmax, linenum)) return NULL; ipn.in_pmax = htons(ipn.in_pmax); } else ipn.in_pmax = ipn.in_pmin; } if ((ipn.in_redir & NAT_BIMAP) == NAT_REDIRECT) { if (!portnum(port2a, &ipn.in_pnext, linenum)) return NULL; ipn.in_pnext = htons(ipn.in_pnext); } if (!(ipn.in_flags & IPN_SPLIT)) ipn.in_inip &= ipn.in_inmsk; if ((ipn.in_flags & IPN_IPRANGE) == 0) ipn.in_outip &= ipn.in_outmsk; ipn.in_srcip &= ipn.in_srcmsk; if ((ipn.in_redir & NAT_MAPBLK) != 0) nat_setgroupmap(&ipn); if (*cpp && !*(cpp+1) && !strcasecmp(*cpp, "frag")) { cpp++; ipn.in_flags |= IPN_FRAG; } if (!*cpp) return &ipn; if (ipn.in_redir != NAT_BIMAP && !strcasecmp(*cpp, "proxy")) { if (ipn.in_redir == NAT_BIMAP) { fprintf(stderr, "%d: cannot use proxy with bimap\n", linenum); return NULL; } cpp++; if (!*cpp) { fprintf(stderr, "%d: missing parameter for \"proxy\"\n", linenum); return NULL; } dport = NULL; if (!strcasecmp(*cpp, "port")) { cpp++; if (!*cpp) { fprintf(stderr, "%d: missing parameter for \"port\"\n", linenum); return NULL; } dport = *cpp; cpp++; if (!*cpp) { fprintf(stderr, "%d: missing parameter for \"proxy\"\n", linenum); return NULL; } } else { fprintf(stderr, "%d: missing keyword \"port\"\n", linenum); return NULL; } if ((proto = index(*cpp, '/'))) { *proto++ = '\0'; if ((pr = getprotobyname(proto))) ipn.in_p = pr->p_proto; else ipn.in_p = atoi(proto); } else ipn.in_p = 0; if (dport && !portnum(dport, &ipn.in_dport, linenum)) return NULL; ipn.in_dport = htons(ipn.in_dport); (void) strncpy(ipn.in_plabel, *cpp, sizeof(ipn.in_plabel)); cpp++; } else if (ipn.in_redir != NAT_BIMAP && !strcasecmp(*cpp, "portmap")) { if (ipn.in_redir == NAT_BIMAP) { fprintf(stderr, "%d: cannot use portmap with bimap\n", linenum); return NULL; } cpp++; if (!*cpp) { fprintf(stderr, "%d: missing expression following portmap\n", linenum); return NULL; } if (!strcasecmp(*cpp, "tcp")) ipn.in_flags |= IPN_TCP; else if (!strcasecmp(*cpp, "udp")) ipn.in_flags |= IPN_UDP; else if (!strcasecmp(*cpp, "tcpudp")) ipn.in_flags |= IPN_TCPUDP; else if (!strcasecmp(*cpp, "tcp/udp")) ipn.in_flags |= IPN_TCPUDP; else { fprintf(stderr, "%d: expected protocol name - got \"%s\"\n", linenum, *cpp); return NULL; } proto = *cpp; cpp++; if (!*cpp) { fprintf(stderr, "%d: no port range found\n", linenum); return NULL; } if (!strcasecmp(*cpp, "auto")) { ipn.in_flags |= IPN_AUTOPORTMAP; ipn.in_pmin = htons(1024); ipn.in_pmax = htons(65535); nat_setgroupmap(&ipn); cpp++; } else { if (!(t = strchr(*cpp, ':'))) { fprintf(stderr, "%d: no port range in \"%s\"\n", linenum, *cpp); return NULL; } *t++ = '\0'; if (!portnum(*cpp, &ipn.in_pmin, linenum) || !portnum(t, &ipn.in_pmax, linenum)) return NULL; ipn.in_pmin = htons(ipn.in_pmin); ipn.in_pmax = htons(ipn.in_pmax); cpp++; } } if (*cpp && !strcasecmp(*cpp, "frag")) { cpp++; ipn.in_flags |= IPN_FRAG; } if (*cpp && !strcasecmp(*cpp, "age")) { cpp++; if (!*cpp) { fprintf(stderr, "%d: age with no parameters\n", linenum); return NULL; } ipn.in_age[0] = atoi(*cpp); s = index(*cpp, '/'); if (s != NULL) ipn.in_age[1] = atoi(s + 1); else ipn.in_age[1] = ipn.in_age[0]; cpp++; } if (*cpp && !strcasecmp(*cpp, "mssclamp")) { cpp++; if (*cpp) { ipn.in_mssclamp = atoi(*cpp); cpp++; } else { fprintf(stderr, "%d: mssclamp with no parameters\n", linenum); return NULL; } } if (*cpp) { fprintf(stderr, "%d: extra junk at the end of the line: %s\n", linenum, *cpp); return NULL; } return &ipn; } void natparsefile(fd, file, opts) int fd; char *file; int opts; { char line[512], *s; ipnat_t *np; FILE *fp; int linenum = 0; if (strcmp(file, "-")) { if (!(fp = fopen(file, "r"))) { fprintf(stderr, "%s: open: %s\n", file, STRERROR(errno)); exit(1); } } else fp = stdin; while (fgets(line, sizeof(line) - 1, fp)) { linenum++; line[sizeof(line) - 1] = '\0'; if ((s = strchr(line, '\n'))) *s = '\0'; if (!(np = natparse(line, linenum))) { if (*line) fprintf(stderr, "%d: syntax error in \"%s\"\n", linenum, line); } else { if ((opts & OPT_VERBOSE) && np) printnat(np, opts); if (!(opts & OPT_NODO)) { if (!(opts & OPT_REMOVE)) { if (ioctl(fd, SIOCADNAT, &np) == -1) { fprintf(stderr, "%d:", linenum); perror("ioctl(SIOCADNAT)"); } } else if (ioctl(fd, SIOCRMNAT, &np) == -1) { fprintf(stderr, "%d:", linenum); perror("ioctl(SIOCRMNAT)"); } } } } if (fp != stdin) fclose(fp); }