From 9e75d32844ede3ffc52b1868e83ee5fc58384648 Mon Sep 17 00:00:00 2001 From: laforge Date: Tue, 26 Mar 2002 12:45:19 +0000 Subject: new ip6 FRAG match by kisza --- extensions/libip6t_frag.c | 273 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 273 insertions(+) create mode 100644 extensions/libip6t_frag.c (limited to 'extensions/libip6t_frag.c') diff --git a/extensions/libip6t_frag.c b/extensions/libip6t_frag.c new file mode 100644 index 0000000..aabb334 --- /dev/null +++ b/extensions/libip6t_frag.c @@ -0,0 +1,273 @@ +/* Shared library add-on to ip6tables to add Fragmentation header support. */ +#include +#include +#include +#include +#include +#include +#include +#include + +/* Function which prints out usage message. */ +static void +help(void) +{ + printf( +"FRAG v%s options:\n" +" --fragid [!] id[:id] match the id (range)\n" +" --fraglen [!] length total length of this header\n" +" --fragres check the reserved filed, too\n" +" --fragfirst matches on the frst fragment\n" +" [--fragmore|--fraglast] there are more fragments or this\n" +" is the last one\n", +NETFILTER_VERSION); +} + +static struct option opts[] = { + { "fragid", 1, 0, '1' }, + { "fraglen", 1, 0, '2' }, + { "fragres", 0, 0, '3' }, + { "fragfirst", 0, 0, '4' }, + { "fragmore", 0, 0, '5' }, + { "fraglast", 0, 0, '6' }, + {0} +}; + +static u_int32_t +parse_frag_id(const char *idstr, const char *typestr) +{ + unsigned long int id; + char* ep; + + id = strtoul(idstr,&ep,0) ; + + if ( idstr == ep ) { + exit_error(PARAMETER_PROBLEM, + "FRAG no valid digits in %s `%s'", typestr, idstr); + } + if ( id == ULONG_MAX && errno == ERANGE ) { + exit_error(PARAMETER_PROBLEM, + "%s `%s' specified too big: would overflow", + typestr, idstr); + } + if ( *idstr != '\0' && *ep != '\0' ) { + exit_error(PARAMETER_PROBLEM, + "FRAG error parsing %s `%s'", typestr, idstr); + } + return (u_int32_t) id; +} + +static void +parse_frag_ids(const char *idstring, u_int32_t *ids) +{ + char *buffer; + char *cp; + + buffer = strdup(idstring); + if ((cp = strchr(buffer, ':')) == NULL) + ids[0] = ids[1] = parse_frag_id(buffer,"id"); + else { + *cp = '\0'; + cp++; + + ids[0] = buffer[0] ? parse_frag_id(buffer,"id") : 0; + ids[1] = cp[0] ? parse_frag_id(cp,"id") : 0xFFFFFFFF; + } + free(buffer); +} + +/* Initialize the match. */ +static void +init(struct ip6t_entry_match *m, unsigned int *nfcache) +{ + struct ip6t_frag *fraginfo = (struct ip6t_frag *)m->data; + + fraginfo->ids[0] = 0x0L; + fraginfo->ids[1] = 0xFFFFFFFF; + fraginfo->hdrlen = 0; + fraginfo->flags = 0; + fraginfo->invflags = 0; +} + +/* Function which parses command options; returns true if it + ate an option */ +static int +parse(int c, char **argv, int invert, unsigned int *flags, + const struct ip6t_entry *entry, + unsigned int *nfcache, + struct ip6t_entry_match **match) +{ + struct ip6t_frag *fraginfo = (struct ip6t_frag *)(*match)->data; + + switch (c) { + case '1': + if (*flags & IP6T_FRAG_IDS) + exit_error(PARAMETER_PROBLEM, + "Only one `--fragid' allowed"); + check_inverse(optarg, &invert, &optind, 0); + parse_frag_ids(argv[optind-1], fraginfo->ids); + if (invert) + fraginfo->invflags |= IP6T_FRAG_INV_IDS; + fraginfo->flags |= IP6T_FRAG_IDS; + *flags |= IP6T_FRAG_IDS; + break; + case '2': + if (*flags & IP6T_FRAG_LEN) + exit_error(PARAMETER_PROBLEM, + "Only one `--fraglen' allowed"); + check_inverse(optarg, &invert, &optind, 0); + fraginfo->hdrlen = parse_frag_id(argv[optind-1], "length"); + if (invert) + fraginfo->invflags |= IP6T_FRAG_INV_LEN; + fraginfo->flags |= IP6T_FRAG_LEN; + *flags |= IP6T_FRAG_LEN; + break; + case '3': + if (*flags & IP6T_FRAG_RES) + exit_error(PARAMETER_PROBLEM, + "Only one `--fragres' allowed"); + fraginfo->flags |= IP6T_FRAG_RES; + *flags |= IP6T_FRAG_RES; + break; + case '4': + if (*flags & IP6T_FRAG_FST) + exit_error(PARAMETER_PROBLEM, + "Only one `--fragfirst' allowed"); + fraginfo->flags |= IP6T_FRAG_FST; + *flags |= IP6T_FRAG_FST; + break; + case '5': + if (*flags & (IP6T_FRAG_MF|IP6T_FRAG_NMF)) + exit_error(PARAMETER_PROBLEM, + "Only one `--fragmore' or `--fraglast' allowed"); + fraginfo->flags |= IP6T_FRAG_MF; + *flags |= IP6T_FRAG_MF; + break; + case '6': + if (*flags & (IP6T_FRAG_MF|IP6T_FRAG_NMF)) + exit_error(PARAMETER_PROBLEM, + "Only one `--fragmore' or `--fraglast' allowed"); + fraginfo->flags |= IP6T_FRAG_NMF; + *flags |= IP6T_FRAG_NMF; + break; + default: + return 0; + } + + return 1; +} + +/* Final check; we don't care. */ +static void +final_check(unsigned int flags) +{ +} + +static void +print_ids(const char *name, u_int32_t min, u_int32_t max, + int invert) +{ + const char *inv = invert ? "!" : ""; + + if (min != 0 || max != 0xFFFFFFFF || invert) { + printf("%s", name); + if (min == max) { + printf(":%s", inv); + printf("%u", min); + } else { + printf("s:%s", inv); + printf("%u",min); + printf(":"); + printf("%u",max); + } + printf(" "); + } +} + +static void +print_len(const char *name, u_int32_t len, int invert) +{ + const char *inv = invert ? "!" : ""; + + if (len != 0 || invert) { + printf("%s", name); + printf(":%s", inv); + printf("%u", len); + printf(" "); + } +} + +/* Prints out the union ip6t_matchinfo. */ +static void +print(const struct ip6t_ip6 *ip, + const struct ip6t_entry_match *match, int numeric) +{ + const struct ip6t_frag *frag = (struct ip6t_frag *)match->data; + + printf("frag "); + print_ids("id", frag->ids[0], frag->ids[1], + frag->invflags & IP6T_FRAG_INV_IDS); + print_len("length", frag->hdrlen, + frag->invflags & IP6T_FRAG_INV_LEN); + if (frag->flags & IP6T_FRAG_RES) printf("reserved "); + if (frag->flags & IP6T_FRAG_FST) printf("first "); + if (frag->flags & IP6T_FRAG_MF) printf("more "); + if (frag->flags & IP6T_FRAG_NMF) printf("last "); + if (frag->invflags & ~IP6T_FRAG_INV_MASK) + printf("Unknown invflags: 0x%X ", + frag->invflags & ~IP6T_FRAG_INV_MASK); +} + +/* Saves the union ip6t_matchinfo in parsable form to stdout. */ +static void save(const struct ip6t_ip6 *ip, const struct ip6t_entry_match *match) +{ + const struct ip6t_frag *fraginfo = (struct ip6t_frag *)match->data; + + if (!(fraginfo->ids[0] == 0 + && fraginfo->ids[1] == 0xFFFFFFFF)) { + printf("--fragid %s", + (fraginfo->invflags & IP6T_FRAG_INV_IDS) ? "! " : ""); + if (fraginfo->ids[0] + != fraginfo->ids[1]) + printf("%u:%u ", + fraginfo->ids[0], + fraginfo->ids[1]); + else + printf("%u ", + fraginfo->ids[0]); + } + + if (fraginfo->hdrlen != 0 ) { + printf("--fraglen %s%u ", + (fraginfo->invflags & IP6T_FRAG_INV_LEN) ? "! " : "", + fraginfo->hdrlen); + } + + if (fraginfo->flags & IP6T_FRAG_RES) printf("--fragres "); + if (fraginfo->flags & IP6T_FRAG_FST) printf("--fragfirst "); + if (fraginfo->flags & IP6T_FRAG_MF) printf("--fragmore "); + if (fraginfo->flags & IP6T_FRAG_NMF) printf("--fraglast "); + +} + +static +struct ip6tables_match frag += { NULL, + "frag", + NETFILTER_VERSION, + IP6T_ALIGN(sizeof(struct ip6t_frag)), + IP6T_ALIGN(sizeof(struct ip6t_frag)), + &help, + &init, + &parse, + &final_check, + &print, + &save, + opts +}; + +void +_init(void) +{ + register_match6(&frag); +} -- cgit v1.2.3