diff options
Diffstat (limited to 'extensions/libxt_dccp.c')
| -rw-r--r-- | extensions/libxt_dccp.c | 354 |
1 files changed, 354 insertions, 0 deletions
diff --git a/extensions/libxt_dccp.c b/extensions/libxt_dccp.c new file mode 100644 index 0000000..8d0b13a --- /dev/null +++ b/extensions/libxt_dccp.c @@ -0,0 +1,354 @@ +/* Shared library add-on to iptables for DCCP matching + * + * (C) 2005 by Harald Welte <laforge@netfilter.org> + * + * This program is distributed under the terms of GNU GPL v2, 1991 + * + */ +#include <stdio.h> +#include <string.h> +#include <stdlib.h> +#include <getopt.h> +#include <netdb.h> +#include <ctype.h> + +#include <netinet/in.h> +#include <xtables.h> +#include <linux/dccp.h> +#include <linux/netfilter/x_tables.h> +#include <linux/netfilter/xt_dccp.h> + +#if 0 +#define DEBUGP(format, first...) printf(format, ##first) +#define static +#else +#define DEBUGP(format, fist...) +#endif + +static void dccp_init(struct xt_entry_match *m) +{ + struct xt_dccp_info *einfo = (struct xt_dccp_info *)m->data; + + memset(einfo, 0, sizeof(struct xt_dccp_info)); +} + +static void dccp_help(void) +{ + printf( +"dccp match options\n" +"[!] --source-port port[:port] match source port(s)\n" +" --sport ...\n" +"[!] --destination-port port[:port] match destination port(s)\n" +" --dport ...\n"); +} + +static const struct option dccp_opts[] = { + { .name = "source-port", .has_arg = 1, .val = '1' }, + { .name = "sport", .has_arg = 1, .val = '1' }, + { .name = "destination-port", .has_arg = 1, .val = '2' }, + { .name = "dport", .has_arg = 1, .val = '2' }, + { .name = "dccp-types", .has_arg = 1, .val = '3' }, + { .name = "dccp-option", .has_arg = 1, .val = '4' }, + { .name = NULL } +}; + +static void +parse_dccp_ports(const char *portstring, + u_int16_t *ports) +{ + char *buffer; + char *cp; + + buffer = strdup(portstring); + DEBUGP("%s\n", portstring); + if ((cp = strchr(buffer, ':')) == NULL) { + ports[0] = ports[1] = xtables_parse_port(buffer, "dccp"); + } + else { + *cp = '\0'; + cp++; + + ports[0] = buffer[0] ? xtables_parse_port(buffer, "dccp") : 0; + ports[1] = cp[0] ? xtables_parse_port(cp, "dccp") : 0xFFFF; + + if (ports[0] > ports[1]) + xtables_error(PARAMETER_PROBLEM, + "invalid portrange (min > max)"); + } + free(buffer); +} + +static const char *const dccp_pkt_types[] = { + [DCCP_PKT_REQUEST] = "REQUEST", + [DCCP_PKT_RESPONSE] = "RESPONSE", + [DCCP_PKT_DATA] = "DATA", + [DCCP_PKT_ACK] = "ACK", + [DCCP_PKT_DATAACK] = "DATAACK", + [DCCP_PKT_CLOSEREQ] = "CLOSEREQ", + [DCCP_PKT_CLOSE] = "CLOSE", + [DCCP_PKT_RESET] = "RESET", + [DCCP_PKT_SYNC] = "SYNC", + [DCCP_PKT_SYNCACK] = "SYNCACK", + [DCCP_PKT_INVALID] = "INVALID", +}; + +static u_int16_t +parse_dccp_types(const char *typestring) +{ + u_int16_t typemask = 0; + char *ptr, *buffer; + + buffer = strdup(typestring); + + for (ptr = strtok(buffer, ","); ptr; ptr = strtok(NULL, ",")) { + unsigned int i; + for (i = 0; i < ARRAY_SIZE(dccp_pkt_types); ++i) + if (!strcasecmp(dccp_pkt_types[i], ptr)) { + typemask |= (1 << i); + break; + } + if (i == ARRAY_SIZE(dccp_pkt_types)) + xtables_error(PARAMETER_PROBLEM, + "Unknown DCCP type `%s'", ptr); + } + + free(buffer); + return typemask; +} + +static u_int8_t parse_dccp_option(char *optstring) +{ + unsigned int ret; + + if (!xtables_strtoui(optstring, NULL, &ret, 1, UINT8_MAX)) + xtables_error(PARAMETER_PROBLEM, "Bad DCCP option \"%s\"", + optstring); + + return ret; +} + +static int +dccp_parse(int c, char **argv, int invert, unsigned int *flags, + const void *entry, struct xt_entry_match **match) +{ + struct xt_dccp_info *einfo + = (struct xt_dccp_info *)(*match)->data; + + switch (c) { + case '1': + if (*flags & XT_DCCP_SRC_PORTS) + xtables_error(PARAMETER_PROBLEM, + "Only one `--source-port' allowed"); + einfo->flags |= XT_DCCP_SRC_PORTS; + xtables_check_inverse(optarg, &invert, &optind, 0, argv); + parse_dccp_ports(optarg, einfo->spts); + if (invert) + einfo->invflags |= XT_DCCP_SRC_PORTS; + *flags |= XT_DCCP_SRC_PORTS; + break; + + case '2': + if (*flags & XT_DCCP_DEST_PORTS) + xtables_error(PARAMETER_PROBLEM, + "Only one `--destination-port' allowed"); + einfo->flags |= XT_DCCP_DEST_PORTS; + xtables_check_inverse(optarg, &invert, &optind, 0, argv); + parse_dccp_ports(optarg, einfo->dpts); + if (invert) + einfo->invflags |= XT_DCCP_DEST_PORTS; + *flags |= XT_DCCP_DEST_PORTS; + break; + + case '3': + if (*flags & XT_DCCP_TYPE) + xtables_error(PARAMETER_PROBLEM, + "Only one `--dccp-types' allowed"); + einfo->flags |= XT_DCCP_TYPE; + xtables_check_inverse(optarg, &invert, &optind, 0, argv); + einfo->typemask = parse_dccp_types(optarg); + if (invert) + einfo->invflags |= XT_DCCP_TYPE; + *flags |= XT_DCCP_TYPE; + break; + + case '4': + if (*flags & XT_DCCP_OPTION) + xtables_error(PARAMETER_PROBLEM, + "Only one `--dccp-option' allowed"); + einfo->flags |= XT_DCCP_OPTION; + xtables_check_inverse(optarg, &invert, &optind, 0, argv); + einfo->option = parse_dccp_option(optarg); + if (invert) + einfo->invflags |= XT_DCCP_OPTION; + *flags |= XT_DCCP_OPTION; + break; + default: + return 0; + } + return 1; +} + +static char * +port_to_service(int port) +{ + struct servent *service; + + if ((service = getservbyport(htons(port), "dccp"))) + return service->s_name; + + return NULL; +} + +static void +print_port(u_int16_t port, int numeric) +{ + char *service; + + if (numeric || (service = port_to_service(port)) == NULL) + printf("%u", port); + else + printf("%s", service); +} + +static void +print_ports(const char *name, u_int16_t min, u_int16_t max, + int invert, int numeric) +{ + const char *inv = invert ? "!" : ""; + + if (min != 0 || max != 0xFFFF || invert) { + printf("%s", name); + if (min == max) { + printf(":%s", inv); + print_port(min, numeric); + } else { + printf("s:%s", inv); + print_port(min, numeric); + printf(":"); + print_port(max, numeric); + } + printf(" "); + } +} + +static void +print_types(u_int16_t types, int inverted, int numeric) +{ + int have_type = 0; + + if (inverted) + printf("! "); + + while (types) { + unsigned int i; + + for (i = 0; !(types & (1 << i)); i++); + + if (have_type) + printf(","); + else + have_type = 1; + + if (numeric) + printf("%u", i); + else + printf("%s", dccp_pkt_types[i]); + + types &= ~(1 << i); + } +} + +static void +print_option(u_int8_t option, int invert, int numeric) +{ + if (option || invert) + printf("option=%s%u ", invert ? "!" : "", option); +} + +static void +dccp_print(const void *ip, const struct xt_entry_match *match, int numeric) +{ + const struct xt_dccp_info *einfo = + (const struct xt_dccp_info *)match->data; + + printf("dccp "); + + if (einfo->flags & XT_DCCP_SRC_PORTS) { + print_ports("spt", einfo->spts[0], einfo->spts[1], + einfo->invflags & XT_DCCP_SRC_PORTS, + numeric); + } + + if (einfo->flags & XT_DCCP_DEST_PORTS) { + print_ports("dpt", einfo->dpts[0], einfo->dpts[1], + einfo->invflags & XT_DCCP_DEST_PORTS, + numeric); + } + + if (einfo->flags & XT_DCCP_TYPE) { + print_types(einfo->typemask, + einfo->invflags & XT_DCCP_TYPE, + numeric); + } + + if (einfo->flags & XT_DCCP_OPTION) { + print_option(einfo->option, + einfo->invflags & XT_DCCP_OPTION, numeric); + } +} + +static void dccp_save(const void *ip, const struct xt_entry_match *match) +{ + const struct xt_dccp_info *einfo = + (const struct xt_dccp_info *)match->data; + + if (einfo->flags & XT_DCCP_SRC_PORTS) { + if (einfo->invflags & XT_DCCP_SRC_PORTS) + printf("! "); + if (einfo->spts[0] != einfo->spts[1]) + printf("--sport %u:%u ", + einfo->spts[0], einfo->spts[1]); + else + printf("--sport %u ", einfo->spts[0]); + } + + if (einfo->flags & XT_DCCP_DEST_PORTS) { + if (einfo->invflags & XT_DCCP_DEST_PORTS) + printf("! "); + if (einfo->dpts[0] != einfo->dpts[1]) + printf("--dport %u:%u ", + einfo->dpts[0], einfo->dpts[1]); + else + printf("--dport %u ", einfo->dpts[0]); + } + + if (einfo->flags & XT_DCCP_TYPE) { + printf("--dccp-type "); + print_types(einfo->typemask, einfo->invflags & XT_DCCP_TYPE,0); + } + + if (einfo->flags & XT_DCCP_OPTION) { + printf("--dccp-option %s%u ", + einfo->typemask & XT_DCCP_OPTION ? "! " : "", + einfo->option); + } +} + +static struct xtables_match dccp_match = { + .name = "dccp", + .family = NFPROTO_UNSPEC, + .version = XTABLES_VERSION, + .size = XT_ALIGN(sizeof(struct xt_dccp_info)), + .userspacesize = XT_ALIGN(sizeof(struct xt_dccp_info)), + .help = dccp_help, + .init = dccp_init, + .parse = dccp_parse, + .print = dccp_print, + .save = dccp_save, + .extra_opts = dccp_opts, +}; + +void _init(void) +{ + xtables_register_match(&dccp_match); +} |