From f22c085fe68bb827b15d235fee307f054c4f85a4 Mon Sep 17 00:00:00 2001 From: rusty Date: Tue, 2 May 2000 16:45:16 +0000 Subject: IPv6 enhancements. --- libiptc/libip4tc.c | 444 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 444 insertions(+) create mode 100644 libiptc/libip4tc.c (limited to 'libiptc/libip4tc.c') diff --git a/libiptc/libip4tc.c b/libiptc/libip4tc.c new file mode 100644 index 0000000..10ea1be --- /dev/null +++ b/libiptc/libip4tc.c @@ -0,0 +1,444 @@ +/* Library which manipulates firewall rules. Version 0.1. */ + +/* Architecture of firewall rules is as follows: + * + * Chains go INPUT, FORWARD, OUTPUT then user chains. + * Each user chain starts with an ERROR node. + * Every chain ends with an unconditional jump: a RETURN for user chains, + * and a POLICY for built-ins. + */ + +/* (C)1999 Paul ``Rusty'' Russell - Placed under the GNU GPL (See + COPYING for details). */ + +#include +#include +#include +#include +#include + +#ifdef DEBUG_CONNTRACK +#define inline +#endif + +#if !defined(__GLIBC__) || (__GLIBC__ < 2) +typedef unsigned int socklen_t; +#endif + +#include "libiptc/libiptc.h" + +#define IP_VERSION 4 +#define IP_OFFSET 0x1FFF + +#define HOOK_PRE_ROUTING NF_IP_PRE_ROUTING +#define HOOK_LOCAL_IN NF_IP_LOCAL_IN +#define HOOK_FORWARD NF_IP_FORWARD +#define HOOK_LOCAL_OUT NF_IP_LOCAL_OUT +#define HOOK_POST_ROUTING NF_IP_POST_ROUTING + +#define STRUCT_ENTRY_TARGET struct ipt_entry_target +#define STRUCT_ENTRY struct ipt_entry +#define STRUCT_ENTRY_MATCH struct ipt_entry_match +#define STRUCT_GETINFO struct ipt_getinfo +#define STRUCT_GET_ENTRIES struct ipt_get_entries +#define STRUCT_COUNTERS struct ipt_counters +#define STRUCT_COUNTERS_INFO struct ipt_counters_info +#define STRUCT_STANDARD_TARGET struct ipt_standard_target +#define STRUCT_REPLACE struct ipt_replace + +#define STRUCT_TC_HANDLE struct iptc_handle +#define TC_HANDLE_T iptc_handle_t + +#define ENTRY_ITERATE IPT_ENTRY_ITERATE +#define TABLE_MAXNAMELEN IPT_TABLE_MAXNAMELEN +#define FUNCTION_MAXNAMELEN IPT_FUNCTION_MAXNAMELEN + +#define GET_TARGET ipt_get_target + +#define ERROR_TARGET IPT_ERROR_TARGET +#define NUMHOOKS NF_IP_NUMHOOKS + +#define IPT_CHAINLABEL ipt_chainlabel + +#define TC_DUMP_ENTRIES dump_entries +#define TC_IS_CHAIN iptc_is_chain +#define TC_NEXT_CHAIN iptc_next_chain +#define TC_NUM_RULES iptc_num_rules +#define TC_GET_RULE iptc_get_rule +#define TC_GET_TARGET iptc_get_target +#define TC_BUILTIN iptc_builtin +#define TC_GET_POLICY iptc_get_policy +#define TC_INSERT_ENTRY iptc_insert_entry +#define TC_REPLACE_ENTRY iptc_replace_entry +#define TC_APPEND_ENTRY iptc_append_entry +#define TC_DELETE_ENTRY iptc_delete_entry +#define TC_DELETE_NUM_ENTRY iptc_delete_num_entry +#define TC_CHECK_PACKET iptc_check_packet +#define TC_FLUSH_ENTRIES iptc_flush_entries +#define TC_ZERO_ENTRIES iptc_zero_entries +#define TC_CREATE_CHAIN iptc_create_chain +#define TC_GET_REFERENCES iptc_get_references +#define TC_DELETE_CHAIN iptc_delete_chain +#define TC_RENAME_CHAIN iptc_rename_chain +#define TC_SET_POLICY iptc_set_policy +#define TC_GET_RAW_SOCKET iptc_get_raw_socket +#define TC_INIT iptc_init +#define TC_COMMIT iptc_commit +#define TC_STRERROR iptc_strerror + +#define TC_AF AF_INET +#define TC_IPPROTO IPPROTO_IP + +#define SO_SET_REPLACE IPT_SO_SET_REPLACE +#define SO_SET_ADD_COUNTERS IPT_SO_SET_ADD_COUNTERS +#define SO_GET_INFO IPT_SO_GET_INFO +#define SO_GET_ENTRIES IPT_SO_GET_ENTRIES +#define SO_GET_VERSION IPT_SO_GET_VERSION + +#define STANDARD_TARGET IPT_STANDARD_TARGET +#define LABEL_RETURN IPTC_LABEL_RETURN +#define LABEL_ACCEPT IPTC_LABEL_ACCEPT +#define LABEL_DROP IPTC_LABEL_DROP + +#define ALIGN IPT_ALIGN +#define RETURN IPT_RETURN + +#include "libiptc.c" + +#define IP_PARTS_NATIVE(n) \ +(unsigned int)((n)>>24)&0xFF, \ +(unsigned int)((n)>>16)&0xFF, \ +(unsigned int)((n)>>8)&0xFF, \ +(unsigned int)((n)&0xFF) + +#define IP_PARTS(n) IP_PARTS_NATIVE(ntohl(n)) + +int +dump_entry(STRUCT_ENTRY *e, const TC_HANDLE_T handle) +{ + size_t i; + STRUCT_ENTRY_TARGET *t; + + printf("Entry %u (%lu):\n", entry2index(handle, e), + entry2offset(handle, e)); + printf("SRC IP: %u.%u.%u.%u/%u.%u.%u.%u\n", + IP_PARTS(e->ip.src.s_addr),IP_PARTS(e->ip.smsk.s_addr)); + printf("DST IP: %u.%u.%u.%u/%u.%u.%u.%u\n", + IP_PARTS(e->ip.dst.s_addr),IP_PARTS(e->ip.dmsk.s_addr)); + printf("Interface: `%s'/", e->ip.iniface); + for (i = 0; i < IFNAMSIZ; i++) + printf("%c", e->ip.iniface_mask[i] ? 'X' : '.'); + printf("to `%s'/", e->ip.outiface); + for (i = 0; i < IFNAMSIZ; i++) + printf("%c", e->ip.outiface_mask[i] ? 'X' : '.'); + printf("\nProtocol: %u\n", e->ip.proto); + printf("Flags: %02X\n", e->ip.flags); + printf("Invflags: %02X\n", e->ip.invflags); + printf("Counters: %llu packets, %llu bytes\n", + e->counters.pcnt, e->counters.bcnt); + printf("Cache: %08X ", e->nfcache); + if (e->nfcache & NFC_ALTERED) printf("ALTERED "); + if (e->nfcache & NFC_UNKNOWN) printf("UNKNOWN "); + if (e->nfcache & NFC_IP_SRC) printf("IP_SRC "); + if (e->nfcache & NFC_IP_DST) printf("IP_DST "); + if (e->nfcache & NFC_IP_IF_IN) printf("IP_IF_IN "); + if (e->nfcache & NFC_IP_IF_OUT) printf("IP_IF_OUT "); + if (e->nfcache & NFC_IP_TOS) printf("IP_TOS "); + if (e->nfcache & NFC_IP_PROTO) printf("IP_PROTO "); + if (e->nfcache & NFC_IP_OPTIONS) printf("IP_OPTIONS "); + if (e->nfcache & NFC_IP_TCPFLAGS) printf("IP_TCPFLAGS "); + if (e->nfcache & NFC_IP_SRC_PT) printf("IP_SRC_PT "); + if (e->nfcache & NFC_IP_DST_PT) printf("IP_DST_PT "); + if (e->nfcache & NFC_IP_PROTO_UNKNOWN) printf("IP_PROTO_UNKNOWN "); + printf("\n"); + + IPT_MATCH_ITERATE(e, print_match); + + t = GET_TARGET(e); + printf("Target name: `%s' [%u]\n", t->u.user.name, t->u.target_size); + if (strcmp(t->u.user.name, STANDARD_TARGET) == 0) { + int pos = *(int *)t->data; + if (pos < 0) + printf("verdict=%s\n", + pos == -NF_ACCEPT-1 ? "NF_ACCEPT" + : pos == -NF_DROP-1 ? "NF_DROP" + : pos == -NF_QUEUE-1 ? "NF_QUEUE" + : pos == RETURN ? "RETURN" + : "UNKNOWN"); + else + printf("verdict=%u\n", pos); + } else if (strcmp(t->u.user.name, IPT_ERROR_TARGET) == 0) + printf("error=`%s'\n", t->data); + + printf("\n"); + return 0; +} + +static int +is_same(const STRUCT_ENTRY *a, const STRUCT_ENTRY *b, unsigned char *matchmask) +{ + unsigned int i; + STRUCT_ENTRY_TARGET *ta, *tb; + unsigned char *mptr; + + /* Always compare head structures: ignore mask here. */ + if (a->ip.src.s_addr != b->ip.src.s_addr + || a->ip.dst.s_addr != b->ip.dst.s_addr + || a->ip.smsk.s_addr != b->ip.smsk.s_addr + || a->ip.smsk.s_addr != b->ip.smsk.s_addr + || a->ip.proto != b->ip.proto + || a->ip.flags != b->ip.flags + || a->ip.invflags != b->ip.invflags) + return 0; + + for (i = 0; i < IFNAMSIZ; i++) { + if (a->ip.iniface_mask[i] != b->ip.iniface_mask[i]) + return 0; + if ((a->ip.iniface[i] & a->ip.iniface_mask[i]) + != (b->ip.iniface[i] & b->ip.iniface_mask[i])) + return 0; + if (a->ip.outiface_mask[i] != b->ip.outiface_mask[i]) + return 0; + if ((a->ip.outiface[i] & a->ip.outiface_mask[i]) + != (b->ip.outiface[i] & b->ip.outiface_mask[i])) + return 0; + } + + if (a->nfcache != b->nfcache + || a->target_offset != b->target_offset + || a->next_offset != b->next_offset) + return 0; + + mptr = matchmask + sizeof(STRUCT_ENTRY); + if (IPT_MATCH_ITERATE(a, match_different, a->elems, b->elems, &mptr)) + return 0; + + ta = GET_TARGET((STRUCT_ENTRY *)a); + tb = GET_TARGET((STRUCT_ENTRY *)b); + if (ta->u.target_size != tb->u.target_size) + return 0; + if (strcmp(ta->u.user.name, tb->u.user.name) != 0) + return 0; + + mptr += sizeof(*ta); + if (target_different(ta->data, tb->data, + ta->u.target_size - sizeof(*ta), mptr)) + return 0; + + return 1; +} + +/***************************** DEBUGGING ********************************/ +static inline int +unconditional(const struct ipt_ip *ip) +{ + unsigned int i; + + for (i = 0; i < sizeof(*ip)/sizeof(u_int32_t); i++) + if (((u_int32_t *)ip)[i]) + return 0; + + return 1; +} + +static inline int +check_match(const STRUCT_ENTRY_MATCH *m, unsigned int *off) +{ + assert(m->u.match_size >= sizeof(STRUCT_ENTRY_MATCH)); + assert(ALIGN(m->u.match_size) == m->u.match_size); + + (*off) += m->u.match_size; + return 0; +} + +static inline int +check_entry(const STRUCT_ENTRY *e, unsigned int *i, unsigned int *off, + unsigned int user_offset, int *was_return, + TC_HANDLE_T h) +{ + unsigned int toff; + STRUCT_STANDARD_TARGET *t; + + assert(e->target_offset >= sizeof(STRUCT_ENTRY)); + assert(e->next_offset >= e->target_offset + + sizeof(STRUCT_ENTRY_TARGET)); + toff = sizeof(STRUCT_ENTRY); + IPT_MATCH_ITERATE(e, check_match, &toff); + + assert(toff == e->target_offset); + + t = (STRUCT_STANDARD_TARGET *) + GET_TARGET((STRUCT_ENTRY *)e); + /* next_offset will have to be multiple of entry alignment. */ + assert(e->next_offset == ALIGN(e->next_offset)); + assert(e->target_offset == ALIGN(e->target_offset)); + assert(t->target.u.target_size == ALIGN(t->target.u.target_size)); + assert(!TC_IS_CHAIN(t->target.u.user.name, h)); + + if (strcmp(t->target.u.user.name, STANDARD_TARGET) == 0) { + assert(t->target.u.target_size + == ALIGN(sizeof(STRUCT_STANDARD_TARGET))); + + assert(t->verdict == -NF_DROP-1 + || t->verdict == -NF_ACCEPT-1 + || t->verdict == RETURN + || t->verdict < (int)h->entries.size); + + if (t->verdict >= 0) { + STRUCT_ENTRY *te = get_entry(h, t->verdict); + int idx; + + idx = entry2index(h, te); + assert(strcmp(GET_TARGET(te)->u.user.name, + IPT_ERROR_TARGET) + != 0); + assert(te != e); + + /* Prior node must be error node, or this node. */ + assert(t->verdict == entry2offset(h, e)+e->next_offset + || strcmp(GET_TARGET(index2entry(h, idx-1)) + ->u.user.name, IPT_ERROR_TARGET) + == 0); + } + + if (t->verdict == RETURN + && unconditional(&e->ip) + && e->target_offset == sizeof(*e)) + *was_return = 1; + else + *was_return = 0; + } else if (strcmp(t->target.u.user.name, IPT_ERROR_TARGET) == 0) { + assert(t->target.u.target_size + == ALIGN(sizeof(struct ipt_error_target))); + + /* If this is in user area, previous must have been return */ + if (*off > user_offset) + assert(*was_return); + + *was_return = 0; + } + else *was_return = 0; + + if (*off == user_offset) + assert(strcmp(t->target.u.user.name, IPT_ERROR_TARGET) == 0); + + (*off) += e->next_offset; + (*i)++; + return 0; +} + +#ifndef NDEBUG +/* Do every conceivable sanity check on the handle */ +static void +do_check(TC_HANDLE_T h, unsigned int line) +{ + unsigned int i, n; + unsigned int user_offset; /* Offset of first user chain */ + int was_return; + + assert(h->changed == 0 || h->changed == 1); + if (strcmp(h->info.name, "filter") == 0) { + assert(h->info.valid_hooks + == (1 << NF_IP_LOCAL_IN + | 1 << NF_IP_FORWARD + | 1 << NF_IP_LOCAL_OUT)); + + /* Hooks should be first three */ + assert(h->info.hook_entry[NF_IP_LOCAL_IN] == 0); + + n = get_chain_end(h, 0); + n += get_entry(h, n)->next_offset; + assert(h->info.hook_entry[NF_IP_FORWARD] == n); + + n = get_chain_end(h, n); + n += get_entry(h, n)->next_offset; + assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n); + + user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT]; + } else if (strcmp(h->info.name, "nat") == 0) { + assert(h->info.valid_hooks + == (1 << NF_IP_PRE_ROUTING + | 1 << NF_IP_POST_ROUTING + | 1 << NF_IP_LOCAL_OUT)); + + assert(h->info.hook_entry[NF_IP_PRE_ROUTING] == 0); + + n = get_chain_end(h, 0); + n += get_entry(h, n)->next_offset; + assert(h->info.hook_entry[NF_IP_POST_ROUTING] == n); + + n = get_chain_end(h, n); + n += get_entry(h, n)->next_offset; + assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n); + + user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT]; + } else if (strcmp(h->info.name, "mangle") == 0) { + assert(h->info.valid_hooks + == (1 << NF_IP_PRE_ROUTING + | 1 << NF_IP_LOCAL_OUT)); + + /* Hooks should be first three */ + assert(h->info.hook_entry[NF_IP_PRE_ROUTING] == 0); + + n = get_chain_end(h, 0); + n += get_entry(h, n)->next_offset; + assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n); + + user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT]; + } else + abort(); + + /* User chain == end of last builtin + policy entry */ + user_offset = get_chain_end(h, user_offset); + user_offset += get_entry(h, user_offset)->next_offset; + + /* Overflows should be end of entry chains, and unconditional + policy nodes. */ + for (i = 0; i < NUMHOOKS; i++) { + STRUCT_ENTRY *e; + STRUCT_STANDARD_TARGET *t; + + if (!(h->info.valid_hooks & (1 << i))) + continue; + assert(h->info.underflow[i] + == get_chain_end(h, h->info.hook_entry[i])); + + e = get_entry(h, get_chain_end(h, h->info.hook_entry[i])); + assert(unconditional(&e->ip)); + assert(e->target_offset == sizeof(*e)); + assert(e->next_offset == sizeof(*e) + sizeof(*t)); + t = (STRUCT_STANDARD_TARGET *)GET_TARGET(e); + + assert(strcmp(t->target.u.user.name, STANDARD_TARGET)==0); + assert(t->verdict == -NF_DROP-1 || t->verdict == -NF_ACCEPT-1); + + /* Hooks and underflows must be valid entries */ + entry2index(h, get_entry(h, h->info.hook_entry[i])); + entry2index(h, get_entry(h, h->info.underflow[i])); + } + + assert(h->info.size + >= h->info.num_entries * (sizeof(STRUCT_ENTRY) + +sizeof(STRUCT_STANDARD_TARGET))); + + assert(h->entries.size + >= (h->new_number + * (sizeof(STRUCT_ENTRY) + + sizeof(STRUCT_STANDARD_TARGET)))); + assert(strcmp(h->info.name, h->entries.name) == 0); + + i = 0; n = 0; + was_return = 0; + /* Check all the entries. */ + ENTRY_ITERATE(h->entries.entries, h->entries.size, + check_entry, &i, &n, user_offset, &was_return, h); + + assert(i == h->new_number); + assert(n == h->entries.size); + + /* Final entry must be error node */ + assert(strcmp(GET_TARGET(index2entry(h, h->new_number-1)) + ->u.user.name, + IPT_ERROR_TARGET) == 0); +} +#endif /*NDEBUG*/ -- cgit v1.2.3