/* * PPP Filter command Interface * * Written by Toshiharu OHNO (tony-o@iij.ad.jp) * * Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd. * * Redistribution and use in source and binary forms are permitted * provided that the above copyright notice and this paragraph are * duplicated in all such forms and that any documentation, * advertising materials, and other materials related to such * distribution and use acknowledge that the software was developed * by the Internet Initiative Japan. The name of the * IIJ may not be used to endorse or promote products derived * from this software without specific prior written permission. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. * * $Id: filter.c,v 1.24 1998/06/15 19:06:07 brian Exp $ * * TODO: Shoud send ICMP error message when we discard packets. */ #include #include #include #include #include #include #include #include #include #include #include #include "defs.h" #include "command.h" #include "mbuf.h" #include "log.h" #include "iplist.h" #include "timer.h" #include "throughput.h" #include "lqr.h" #include "hdlc.h" #include "fsm.h" #include "lcp.h" #include "ccp.h" #include "link.h" #include "slcompress.h" #include "ipcp.h" #include "filter.h" #include "descriptor.h" #include "prompt.h" #include "mp.h" #include "bundle.h" static int filter_Nam2Proto(int, char const *const *); static int filter_Nam2Op(const char *); static const u_int32_t netmasks[33] = { 0x00000000, 0x80000000, 0xC0000000, 0xE0000000, 0xF0000000, 0xF8000000, 0xFC000000, 0xFE000000, 0xFF000000, 0xFF800000, 0xFFC00000, 0xFFE00000, 0xFFF00000, 0xFFF80000, 0xFFFC0000, 0xFFFE0000, 0xFFFF0000, 0xFFFF8000, 0xFFFFC000, 0xFFFFE000, 0xFFFFF000, 0xFFFFF800, 0xFFFFFC00, 0xFFFFFE00, 0xFFFFFF00, 0xFFFFFF80, 0xFFFFFFC0, 0xFFFFFFE0, 0xFFFFFFF0, 0xFFFFFFF8, 0xFFFFFFFC, 0xFFFFFFFE, 0xFFFFFFFF, }; int ParseAddr(struct ipcp *ipcp, int argc, char const *const *argv, struct in_addr *paddr, struct in_addr *pmask, int *pwidth) { int bits, len; char *wp; const char *cp; if (argc < 1) { log_Printf(LogWARN, "ParseAddr: address/mask is expected.\n"); return (0); } if (pmask) pmask->s_addr = INADDR_BROADCAST; /* Assume 255.255.255.255 as default */ cp = pmask || pwidth ? strchr(*argv, '/') : NULL; len = cp ? cp - *argv : strlen(*argv); if (strncasecmp(*argv, "HISADDR", len) == 0) *paddr = ipcp->peer_ip; else if (strncasecmp(*argv, "MYADDR", len) == 0) *paddr = ipcp->my_ip; else if (len > 15) log_Printf(LogWARN, "ParseAddr: %s: Bad address\n", *argv); else { char s[16]; strncpy(s, *argv, len); s[len] = '\0'; if (inet_aton(s, paddr) == 0) { log_Printf(LogWARN, "ParseAddr: %s: Bad address\n", s); return (0); } } if (cp && *++cp) { bits = strtol(cp, &wp, 0); if (cp == wp || bits < 0 || bits > 32) { log_Printf(LogWARN, "ParseAddr: bad mask width.\n"); return (0); } } else if (paddr->s_addr == INADDR_ANY) /* An IP of 0.0.0.0 without a width is anything */ bits = 0; else /* If a valid IP is given without a width, assume 32 bits */ bits = 32; if (pwidth) *pwidth = bits; if (pmask) pmask->s_addr = htonl(netmasks[bits]); return (1); } static int ParsePort(const char *service, int proto) { const char *protocol_name; char *cp; struct servent *servent; int port; switch (proto) { case P_UDP: protocol_name = "udp"; break; case P_TCP: protocol_name = "tcp"; break; default: protocol_name = 0; } servent = getservbyname(service, protocol_name); if (servent != 0) return (ntohs(servent->s_port)); port = strtol(service, &cp, 0); if (cp == service) { log_Printf(LogWARN, "ParsePort: %s is not a port name or number.\n", service); return (0); } return (port); } /* * ICMP Syntax: src eq icmp_message_type */ static int ParseIcmp(int argc, char const *const *argv, struct filterent *tgt) { int type; char *cp; switch (argc) { case 0: /* permit/deny all ICMP types */ tgt->opt.srcop = OP_NONE; break; case 3: if (!strcmp(*argv, "src") && !strcmp(argv[1], "eq")) { type = strtol(argv[2], &cp, 0); if (cp == argv[2]) { log_Printf(LogWARN, "ParseIcmp: type is expected.\n"); return (0); } tgt->opt.srcop = OP_EQ; tgt->opt.srcport = type; } break; default: log_Printf(LogWARN, "ParseIcmp: bad icmp syntax.\n"); return (0); } return (1); } /* * UDP Syntax: [src op port] [dst op port] */ static int ParseUdpOrTcp(int argc, char const *const *argv, int proto, struct filterent *tgt) { tgt->opt.srcop = tgt->opt.dstop = OP_NONE; tgt->opt.estab = tgt->opt.syn = tgt->opt.finrst = 0; if (argc >= 3 && !strcmp(*argv, "src")) { tgt->opt.srcop = filter_Nam2Op(argv[1]); if (tgt->opt.srcop == OP_NONE) { log_Printf(LogWARN, "ParseUdpOrTcp: bad operation\n"); return (0); } tgt->opt.srcport = ParsePort(argv[2], proto); if (tgt->opt.srcport == 0) return (0); argc -= 3; argv += 3; } if (argc >= 3 && !strcmp(argv[0], "dst")) { tgt->opt.dstop = filter_Nam2Op(argv[1]); if (tgt->opt.dstop == OP_NONE) { log_Printf(LogWARN, "ParseUdpOrTcp: bad operation\n"); return (0); } tgt->opt.dstport = ParsePort(argv[2], proto); if (tgt->opt.dstport == 0) return (0); argc -= 3; argv += 3; } if (proto == P_TCP) { for (; argc > 0; argc--, argv++) if (!strcmp(*argv, "estab")) tgt->opt.estab = 1; else if (!strcmp(*argv, "syn")) tgt->opt.syn = 1; else if (!strcmp(*argv, "finrst")) tgt->opt.finrst = 1; else break; } if (argc > 0) { log_Printf(LogWARN, "ParseUdpOrTcp: bad src/dst port syntax: %s\n", *argv); return 0; } return 1; } static int Parse(struct ipcp *ipcp, int argc, char const *const *argv, struct filterent *ofp) { int action, proto; int val; char *wp; struct filterent filterdata; val = strtol(*argv, &wp, 0); if (*argv == wp || val > MAXFILTERS) { log_Printf(LogWARN, "Parse: invalid filter number.\n"); return (0); } if (val < 0) { for (val = 0; val < MAXFILTERS; val++) { ofp->action = A_NONE; ofp++; } log_Printf(LogWARN, "Parse: filter cleared.\n"); return (1); } ofp += val; if (--argc == 0) { log_Printf(LogWARN, "Parse: missing action.\n"); return (0); } argv++; proto = P_NONE; memset(&filterdata, '\0', sizeof filterdata); if (!strcmp(*argv, "permit")) { action = A_PERMIT; } else if (!strcmp(*argv, "deny")) { action = A_DENY; } else if (!strcmp(*argv, "clear")) { ofp->action = A_NONE; return (1); } else { log_Printf(LogWARN, "Parse: bad action: %s\n", *argv); return (0); } filterdata.action = action; argc--; argv++; if (filterdata.action == A_DENY) { if (!strcmp(*argv, "host")) { filterdata.action |= A_UHOST; argc--; argv++; } else if (!strcmp(*argv, "port")) { filterdata.action |= A_UPORT; argc--; argv++; } } proto = filter_Nam2Proto(argc, argv); if (proto == P_NONE) { if (ParseAddr(ipcp, argc, argv, &filterdata.saddr, &filterdata.smask, &filterdata.swidth)) { argc--; argv++; proto = filter_Nam2Proto(argc, argv); if (proto == P_NONE) { if (ParseAddr(ipcp, argc, argv, &filterdata.daddr, &filterdata.dmask, &filterdata.dwidth)) { argc--; argv++; } proto = filter_Nam2Proto(argc, argv); if (proto != P_NONE) { argc--; argv++; } } else { argc--; argv++; } } else { log_Printf(LogWARN, "Parse: Address/protocol expected.\n"); return (0); } } else { argc--; argv++; } val = 1; filterdata.proto = proto; switch (proto) { case P_TCP: val = ParseUdpOrTcp(argc, argv, P_TCP, &filterdata); break; case P_UDP: val = ParseUdpOrTcp(argc, argv, P_UDP, &filterdata); break; case P_ICMP: val = ParseIcmp(argc, argv, &filterdata); break; } log_Printf(LogDEBUG, "Parse: Src: %s\n", inet_ntoa(filterdata.saddr)); log_Printf(LogDEBUG, "Parse: Src mask: %s\n", inet_ntoa(filterdata.smask)); log_Printf(LogDEBUG, "Parse: Dst: %s\n", inet_ntoa(filterdata.daddr)); log_Printf(LogDEBUG, "Parse: Dst mask: %s\n", inet_ntoa(filterdata.dmask)); log_Printf(LogDEBUG, "Parse: Proto = %d\n", proto); log_Printf(LogDEBUG, "Parse: src: %s (%d)\n", filter_Op2Nam(filterdata.opt.srcop), filterdata.opt.srcport); log_Printf(LogDEBUG, "Parse: dst: %s (%d)\n", filter_Op2Nam(filterdata.opt.dstop), filterdata.opt.dstport); log_Printf(LogDEBUG, "Parse: estab: %u\n", filterdata.opt.estab); log_Printf(LogDEBUG, "Parse: syn: %u\n", filterdata.opt.syn); log_Printf(LogDEBUG, "Parse: finrst: %u\n", filterdata.opt.finrst); if (val) *ofp = filterdata; return (val); } int filter_Set(struct cmdargs const *arg) { struct filter *filter; if (arg->argc < arg->argn+2) return -1; if (!strcmp(arg->argv[arg->argn], "in")) filter = &arg->bundle->filter.in; else if (!strcmp(arg->argv[arg->argn], "out")) filter = &arg->bundle->filter.out; else if (!strcmp(arg->argv[arg->argn], "dial")) filter = &arg->bundle->filter.dial; else if (!strcmp(arg->argv[arg->argn], "alive")) filter = &arg->bundle->filter.alive; else { log_Printf(LogWARN, "filter_Set: %s: Invalid filter name.\n", arg->argv[arg->argn]); return -1; } Parse(&arg->bundle->ncp.ipcp, arg->argc - arg->argn - 1, arg->argv + arg->argn + 1, filter->rule); return 0; } const char * filter_Action2Nam(int act) { static const char *actname[] = { "none ", "permit ", "deny " }; return actname[act & (A_PERMIT|A_DENY)]; } static void doShowFilter(struct filterent *fp, struct prompt *prompt) { int n; for (n = 0; n < MAXFILTERS; n++, fp++) { if (fp->action != A_NONE) { prompt_Printf(prompt, " %2d %s", n, filter_Action2Nam(fp->action)); if (fp->action & A_UHOST) prompt_Printf(prompt, "host "); else if (fp->action & A_UPORT) prompt_Printf(prompt, "port "); else prompt_Printf(prompt, " "); prompt_Printf(prompt, "%s/%d ", inet_ntoa(fp->saddr), fp->swidth); prompt_Printf(prompt, "%s/%d ", inet_ntoa(fp->daddr), fp->dwidth); if (fp->proto) { prompt_Printf(prompt, "%s", filter_Proto2Nam(fp->proto)); if (fp->opt.srcop) prompt_Printf(prompt, " src %s %d", filter_Op2Nam(fp->opt.srcop), fp->opt.srcport); if (fp->opt.dstop) prompt_Printf(prompt, " dst %s %d", filter_Op2Nam(fp->opt.dstop), fp->opt.dstport); if (fp->opt.estab) prompt_Printf(prompt, " estab"); if (fp->opt.syn) prompt_Printf(prompt, " syn"); if (fp->opt.finrst) prompt_Printf(prompt, " finrst"); } prompt_Printf(prompt, "\n"); } } } int filter_Show(struct cmdargs const *arg) { if (arg->argc > arg->argn+1) return -1; if (arg->argc == arg->argn+1) { struct filter *filter; if (!strcmp(arg->argv[arg->argn], "in")) filter = &arg->bundle->filter.in; else if (!strcmp(arg->argv[arg->argn], "out")) filter = &arg->bundle->filter.out; else if (!strcmp(arg->argv[arg->argn], "dial")) filter = &arg->bundle->filter.dial; else if (!strcmp(arg->argv[arg->argn], "alive")) filter = &arg->bundle->filter.alive; else return -1; doShowFilter(filter->rule, arg->prompt); } else { struct filter *filter[4]; int f; filter[0] = &arg->bundle->filter.in; filter[1] = &arg->bundle->filter.out; filter[2] = &arg->bundle->filter.dial; filter[3] = &arg->bundle->filter.alive; for (f = 0; f < 4; f++) { if (f) prompt_Printf(arg->prompt, "\n"); prompt_Printf(arg->prompt, "%s:\n", filter[f]->name); doShowFilter(filter[f]->rule, arg->prompt); } } return 0; } static const char *protoname[] = { "none", "tcp", "udp", "icmp" }; const char * filter_Proto2Nam(int proto) { if (proto >= sizeof protoname / sizeof protoname[0]) return "unknown"; return protoname[proto]; } static int filter_Nam2Proto(int argc, char const *const *argv) { int proto; if (argc == 0) proto = 0; else for (proto = sizeof protoname / sizeof protoname[0] - 1; proto; proto--) if (!strcasecmp(*argv, protoname[proto])) break; return proto; } static const char *opname[] = {"none", "eq", "gt", "unknown", "lt"}; const char * filter_Op2Nam(int op) { if (op >= sizeof opname / sizeof opname[0]) return "unknown"; return opname[op]; } static int filter_Nam2Op(const char *cp) { int op; for (op = sizeof opname / sizeof opname[0] - 1; op; op--) if (!strcasecmp(cp, opname[op])) break; return op; }