/* Library which manipulates firewall rules. Version 0.1. */
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/* Architecture of firewall rules is as follows:
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*
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* Chains go INPUT, FORWARD, OUTPUT then user chains.
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* Each user chain starts with an ERROR node.
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* Every chain ends with an unconditional jump: a RETURN for user chains,
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* and a POLICY for built-ins.
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*/
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/* (C)1999 Paul ``Rusty'' Russell - Placed under the GNU GPL (See
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COPYING for details). */
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#include <assert.h>
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#include <string.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <unistd.h>
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#ifdef DEBUG_CONNTRACK
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#define inline
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#endif
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#if !defined(__ANDROID__) && (!defined(__GLIBC__) || (__GLIBC__ < 2))
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typedef unsigned int socklen_t;
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#endif
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#include "libiptc/libiptc.h"
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#define IP_VERSION 4
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#define IP_OFFSET 0x1FFF
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#define HOOK_PRE_ROUTING NF_IP_PRE_ROUTING
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#define HOOK_LOCAL_IN NF_IP_LOCAL_IN
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#define HOOK_FORWARD NF_IP_FORWARD
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#define HOOK_LOCAL_OUT NF_IP_LOCAL_OUT
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#define HOOK_POST_ROUTING NF_IP_POST_ROUTING
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#define STRUCT_ENTRY_TARGET struct xt_entry_target
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#define STRUCT_ENTRY struct ipt_entry
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#define STRUCT_ENTRY_MATCH struct xt_entry_match
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#define STRUCT_GETINFO struct ipt_getinfo
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#define STRUCT_GET_ENTRIES struct ipt_get_entries
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#define STRUCT_COUNTERS struct xt_counters
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#define STRUCT_COUNTERS_INFO struct xt_counters_info
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#define STRUCT_STANDARD_TARGET struct xt_standard_target
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#define STRUCT_REPLACE struct ipt_replace
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#define ENTRY_ITERATE IPT_ENTRY_ITERATE
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#define TABLE_MAXNAMELEN XT_TABLE_MAXNAMELEN
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#define FUNCTION_MAXNAMELEN XT_FUNCTION_MAXNAMELEN
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#define GET_TARGET ipt_get_target
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#define ERROR_TARGET XT_ERROR_TARGET
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#define NUMHOOKS NF_IP_NUMHOOKS
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#define IPT_CHAINLABEL xt_chainlabel
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#define TC_DUMP_ENTRIES dump_entries
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#define TC_IS_CHAIN iptc_is_chain
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#define TC_FIRST_CHAIN iptc_first_chain
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#define TC_NEXT_CHAIN iptc_next_chain
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#define TC_FIRST_RULE iptc_first_rule
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#define TC_NEXT_RULE iptc_next_rule
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#define TC_GET_TARGET iptc_get_target
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#define TC_BUILTIN iptc_builtin
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#define TC_GET_POLICY iptc_get_policy
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#define TC_INSERT_ENTRY iptc_insert_entry
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#define TC_REPLACE_ENTRY iptc_replace_entry
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#define TC_APPEND_ENTRY iptc_append_entry
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#define TC_CHECK_ENTRY iptc_check_entry
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#define TC_DELETE_ENTRY iptc_delete_entry
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#define TC_DELETE_NUM_ENTRY iptc_delete_num_entry
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#define TC_FLUSH_ENTRIES iptc_flush_entries
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#define TC_ZERO_ENTRIES iptc_zero_entries
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#define TC_READ_COUNTER iptc_read_counter
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#define TC_ZERO_COUNTER iptc_zero_counter
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#define TC_SET_COUNTER iptc_set_counter
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#define TC_CREATE_CHAIN iptc_create_chain
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#define TC_GET_REFERENCES iptc_get_references
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#define TC_DELETE_CHAIN iptc_delete_chain
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#define TC_RENAME_CHAIN iptc_rename_chain
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#define TC_SET_POLICY iptc_set_policy
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#define TC_GET_RAW_SOCKET iptc_get_raw_socket
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#define TC_INIT iptc_init
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#define TC_FREE iptc_free
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#define TC_COMMIT iptc_commit
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#define TC_STRERROR iptc_strerror
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#define TC_NUM_RULES iptc_num_rules
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#define TC_GET_RULE iptc_get_rule
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#define TC_OPS iptc_ops
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#define TC_AF AF_INET
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#define TC_IPPROTO IPPROTO_IP
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#define SO_SET_REPLACE IPT_SO_SET_REPLACE
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#define SO_SET_ADD_COUNTERS IPT_SO_SET_ADD_COUNTERS
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#define SO_GET_INFO IPT_SO_GET_INFO
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#define SO_GET_ENTRIES IPT_SO_GET_ENTRIES
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#define SO_GET_VERSION IPT_SO_GET_VERSION
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#define STANDARD_TARGET XT_STANDARD_TARGET
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#define LABEL_RETURN IPTC_LABEL_RETURN
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#define LABEL_ACCEPT IPTC_LABEL_ACCEPT
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#define LABEL_DROP IPTC_LABEL_DROP
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#define LABEL_QUEUE IPTC_LABEL_QUEUE
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#define ALIGN XT_ALIGN
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#define RETURN XT_RETURN
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#include "libiptc.c"
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#define IP_PARTS_NATIVE(n) \
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(unsigned int)((n)>>24)&0xFF, \
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(unsigned int)((n)>>16)&0xFF, \
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(unsigned int)((n)>>8)&0xFF, \
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(unsigned int)((n)&0xFF)
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#define IP_PARTS(n) IP_PARTS_NATIVE(ntohl(n))
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static int
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dump_entry(struct ipt_entry *e, struct xtc_handle *const handle)
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{
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size_t i;
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STRUCT_ENTRY_TARGET *t;
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printf("Entry %u (%lu):\n", iptcb_entry2index(handle, e),
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iptcb_entry2offset(handle, e));
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printf("SRC IP: %u.%u.%u.%u/%u.%u.%u.%u\n",
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IP_PARTS(e->ip.src.s_addr),IP_PARTS(e->ip.smsk.s_addr));
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printf("DST IP: %u.%u.%u.%u/%u.%u.%u.%u\n",
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IP_PARTS(e->ip.dst.s_addr),IP_PARTS(e->ip.dmsk.s_addr));
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printf("Interface: `%s'/", e->ip.iniface);
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for (i = 0; i < IFNAMSIZ; i++)
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printf("%c", e->ip.iniface_mask[i] ? 'X' : '.');
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printf("to `%s'/", e->ip.outiface);
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for (i = 0; i < IFNAMSIZ; i++)
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printf("%c", e->ip.outiface_mask[i] ? 'X' : '.');
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printf("\nProtocol: %u\n", e->ip.proto);
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printf("Flags: %02X\n", e->ip.flags);
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printf("Invflags: %02X\n", e->ip.invflags);
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printf("Counters: %llu packets, %llu bytes\n",
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(unsigned long long)e->counters.pcnt, (unsigned long long)e->counters.bcnt);
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printf("Cache: %08X\n", e->nfcache);
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IPT_MATCH_ITERATE(e, print_match);
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t = GET_TARGET(e);
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printf("Target name: `%s' [%u]\n", t->u.user.name, t->u.target_size);
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if (strcmp(t->u.user.name, STANDARD_TARGET) == 0) {
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const unsigned char *data = t->data;
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int pos = *(const int *)data;
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if (pos < 0)
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printf("verdict=%s\n",
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pos == -NF_ACCEPT-1 ? "NF_ACCEPT"
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: pos == -NF_DROP-1 ? "NF_DROP"
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: pos == -NF_QUEUE-1 ? "NF_QUEUE"
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: pos == RETURN ? "RETURN"
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: "UNKNOWN");
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else
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printf("verdict=%u\n", pos);
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} else if (strcmp(t->u.user.name, XT_ERROR_TARGET) == 0)
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printf("error=`%s'\n", t->data);
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printf("\n");
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return 0;
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}
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static unsigned char *
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is_same(const STRUCT_ENTRY *a, const STRUCT_ENTRY *b, unsigned char *matchmask)
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{
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unsigned int i;
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unsigned char *mptr;
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/* Always compare head structures: ignore mask here. */
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if (a->ip.src.s_addr != b->ip.src.s_addr
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|| a->ip.dst.s_addr != b->ip.dst.s_addr
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|| a->ip.smsk.s_addr != b->ip.smsk.s_addr
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|| a->ip.dmsk.s_addr != b->ip.dmsk.s_addr
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|| a->ip.proto != b->ip.proto
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|| a->ip.flags != b->ip.flags
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|| a->ip.invflags != b->ip.invflags)
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return NULL;
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for (i = 0; i < IFNAMSIZ; i++) {
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if (a->ip.iniface_mask[i] != b->ip.iniface_mask[i])
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return NULL;
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if ((a->ip.iniface[i] & a->ip.iniface_mask[i])
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!= (b->ip.iniface[i] & b->ip.iniface_mask[i]))
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return NULL;
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if (a->ip.outiface_mask[i] != b->ip.outiface_mask[i])
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return NULL;
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if ((a->ip.outiface[i] & a->ip.outiface_mask[i])
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!= (b->ip.outiface[i] & b->ip.outiface_mask[i]))
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return NULL;
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}
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if (a->target_offset != b->target_offset
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|| a->next_offset != b->next_offset)
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return NULL;
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mptr = matchmask + sizeof(STRUCT_ENTRY);
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if (IPT_MATCH_ITERATE(a, match_different, a->elems, b->elems, &mptr))
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return NULL;
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mptr += XT_ALIGN(sizeof(struct xt_entry_target));
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return mptr;
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}
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#if 0
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/***************************** DEBUGGING ********************************/
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static inline int
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unconditional(const struct ipt_ip *ip)
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{
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unsigned int i;
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for (i = 0; i < sizeof(*ip)/sizeof(uint32_t); i++)
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if (((uint32_t *)ip)[i])
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return 0;
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return 1;
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}
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static inline int
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check_match(const STRUCT_ENTRY_MATCH *m, unsigned int *off)
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{
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assert(m->u.match_size >= sizeof(STRUCT_ENTRY_MATCH));
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assert(ALIGN(m->u.match_size) == m->u.match_size);
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(*off) += m->u.match_size;
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return 0;
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}
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static inline int
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check_entry(const STRUCT_ENTRY *e, unsigned int *i, unsigned int *off,
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unsigned int user_offset, int *was_return,
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struct xtc_handle *h)
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{
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unsigned int toff;
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STRUCT_STANDARD_TARGET *t;
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assert(e->target_offset >= sizeof(STRUCT_ENTRY));
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assert(e->next_offset >= e->target_offset
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+ sizeof(STRUCT_ENTRY_TARGET));
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toff = sizeof(STRUCT_ENTRY);
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IPT_MATCH_ITERATE(e, check_match, &toff);
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assert(toff == e->target_offset);
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t = (STRUCT_STANDARD_TARGET *)
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GET_TARGET((STRUCT_ENTRY *)e);
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/* next_offset will have to be multiple of entry alignment. */
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assert(e->next_offset == ALIGN(e->next_offset));
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assert(e->target_offset == ALIGN(e->target_offset));
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assert(t->target.u.target_size == ALIGN(t->target.u.target_size));
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assert(!TC_IS_CHAIN(t->target.u.user.name, h));
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if (strcmp(t->target.u.user.name, STANDARD_TARGET) == 0) {
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assert(t->target.u.target_size
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== ALIGN(sizeof(STRUCT_STANDARD_TARGET)));
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assert(t->verdict == -NF_DROP-1
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|| t->verdict == -NF_ACCEPT-1
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|| t->verdict == RETURN
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|| t->verdict < (int)h->entries->size);
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if (t->verdict >= 0) {
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STRUCT_ENTRY *te = get_entry(h, t->verdict);
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int idx;
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idx = iptcb_entry2index(h, te);
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assert(strcmp(GET_TARGET(te)->u.user.name,
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XT_ERROR_TARGET)
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!= 0);
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assert(te != e);
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/* Prior node must be error node, or this node. */
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assert(t->verdict == iptcb_entry2offset(h, e)+e->next_offset
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|| strcmp(GET_TARGET(index2entry(h, idx-1))
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->u.user.name, XT_ERROR_TARGET)
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== 0);
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}
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if (t->verdict == RETURN
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&& unconditional(&e->ip)
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&& e->target_offset == sizeof(*e))
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*was_return = 1;
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else
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*was_return = 0;
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} else if (strcmp(t->target.u.user.name, XT_ERROR_TARGET) == 0) {
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assert(t->target.u.target_size
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== ALIGN(sizeof(struct ipt_error_target)));
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/* If this is in user area, previous must have been return */
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if (*off > user_offset)
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assert(*was_return);
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*was_return = 0;
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}
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else *was_return = 0;
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if (*off == user_offset)
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assert(strcmp(t->target.u.user.name, XT_ERROR_TARGET) == 0);
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(*off) += e->next_offset;
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(*i)++;
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return 0;
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}
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#ifdef IPTC_DEBUG
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/* Do every conceivable sanity check on the handle */
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static void
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do_check(struct xtc_handle *h, unsigned int line)
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{
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unsigned int i, n;
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unsigned int user_offset; /* Offset of first user chain */
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int was_return;
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assert(h->changed == 0 || h->changed == 1);
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if (strcmp(h->info.name, "filter") == 0) {
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assert(h->info.valid_hooks
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== (1 << NF_IP_LOCAL_IN
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| 1 << NF_IP_FORWARD
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| 1 << NF_IP_LOCAL_OUT));
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/* Hooks should be first three */
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assert(h->info.hook_entry[NF_IP_LOCAL_IN] == 0);
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n = get_chain_end(h, 0);
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n += get_entry(h, n)->next_offset;
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assert(h->info.hook_entry[NF_IP_FORWARD] == n);
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n = get_chain_end(h, n);
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n += get_entry(h, n)->next_offset;
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assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);
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user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];
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} else if (strcmp(h->info.name, "nat") == 0) {
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assert((h->info.valid_hooks
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== (1 << NF_IP_PRE_ROUTING
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| 1 << NF_IP_POST_ROUTING
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| 1 << NF_IP_LOCAL_OUT)) ||
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(h->info.valid_hooks
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== (1 << NF_IP_PRE_ROUTING
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| 1 << NF_IP_LOCAL_IN
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| 1 << NF_IP_POST_ROUTING
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| 1 << NF_IP_LOCAL_OUT)));
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assert(h->info.hook_entry[NF_IP_PRE_ROUTING] == 0);
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n = get_chain_end(h, 0);
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n += get_entry(h, n)->next_offset;
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assert(h->info.hook_entry[NF_IP_POST_ROUTING] == n);
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n = get_chain_end(h, n);
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n += get_entry(h, n)->next_offset;
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assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);
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user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];
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if (h->info.valid_hooks & (1 << NF_IP_LOCAL_IN)) {
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n = get_chain_end(h, n);
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n += get_entry(h, n)->next_offset;
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assert(h->info.hook_entry[NF_IP_LOCAL_IN] == n);
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user_offset = h->info.hook_entry[NF_IP_LOCAL_IN];
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}
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} else if (strcmp(h->info.name, "mangle") == 0) {
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/* This code is getting ugly because linux < 2.4.18-pre6 had
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* two mangle hooks, linux >= 2.4.18-pre6 has five mangle hooks
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* */
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assert((h->info.valid_hooks
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== (1 << NF_IP_PRE_ROUTING
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| 1 << NF_IP_LOCAL_OUT)) ||
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(h->info.valid_hooks
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== (1 << NF_IP_PRE_ROUTING
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| 1 << NF_IP_LOCAL_IN
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| 1 << NF_IP_FORWARD
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| 1 << NF_IP_LOCAL_OUT
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| 1 << NF_IP_POST_ROUTING)));
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/* Hooks should be first five */
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assert(h->info.hook_entry[NF_IP_PRE_ROUTING] == 0);
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n = get_chain_end(h, 0);
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if (h->info.valid_hooks & (1 << NF_IP_LOCAL_IN)) {
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n += get_entry(h, n)->next_offset;
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assert(h->info.hook_entry[NF_IP_LOCAL_IN] == n);
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n = get_chain_end(h, n);
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}
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if (h->info.valid_hooks & (1 << NF_IP_FORWARD)) {
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n += get_entry(h, n)->next_offset;
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assert(h->info.hook_entry[NF_IP_FORWARD] == n);
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n = get_chain_end(h, n);
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}
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n += get_entry(h, n)->next_offset;
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assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);
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user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];
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if (h->info.valid_hooks & (1 << NF_IP_POST_ROUTING)) {
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n = get_chain_end(h, n);
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n += get_entry(h, n)->next_offset;
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assert(h->info.hook_entry[NF_IP_POST_ROUTING] == n);
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user_offset = h->info.hook_entry[NF_IP_POST_ROUTING];
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}
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} else if (strcmp(h->info.name, "raw") == 0) {
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assert(h->info.valid_hooks
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== (1 << NF_IP_PRE_ROUTING
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| 1 << NF_IP_LOCAL_OUT));
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/* Hooks should be first three */
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assert(h->info.hook_entry[NF_IP_PRE_ROUTING] == 0);
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n = get_chain_end(h, n);
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n += get_entry(h, n)->next_offset;
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assert(h->info.hook_entry[NF_IP_LOCAL_OUT] == n);
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user_offset = h->info.hook_entry[NF_IP_LOCAL_OUT];
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} else {
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fprintf(stderr, "Unknown table `%s'\n", h->info.name);
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abort();
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}
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/* User chain == end of last builtin + policy entry */
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user_offset = get_chain_end(h, user_offset);
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user_offset += get_entry(h, user_offset)->next_offset;
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/* Overflows should be end of entry chains, and unconditional
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policy nodes. */
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for (i = 0; i < NUMHOOKS; i++) {
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STRUCT_ENTRY *e;
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STRUCT_STANDARD_TARGET *t;
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if (!(h->info.valid_hooks & (1 << i)))
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continue;
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assert(h->info.underflow[i]
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== get_chain_end(h, h->info.hook_entry[i]));
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e = get_entry(h, get_chain_end(h, h->info.hook_entry[i]));
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assert(unconditional(&e->ip));
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assert(e->target_offset == sizeof(*e));
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t = (STRUCT_STANDARD_TARGET *)GET_TARGET(e);
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assert(t->target.u.target_size == ALIGN(sizeof(*t)));
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assert(e->next_offset == sizeof(*e) + ALIGN(sizeof(*t)));
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assert(strcmp(t->target.u.user.name, STANDARD_TARGET)==0);
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assert(t->verdict == -NF_DROP-1 || t->verdict == -NF_ACCEPT-1);
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/* Hooks and underflows must be valid entries */
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entry2index(h, get_entry(h, h->info.hook_entry[i]));
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entry2index(h, get_entry(h, h->info.underflow[i]));
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}
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assert(h->info.size
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>= h->info.num_entries * (sizeof(STRUCT_ENTRY)
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+sizeof(STRUCT_STANDARD_TARGET)));
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assert(h->entries.size
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>= (h->new_number
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* (sizeof(STRUCT_ENTRY)
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+ sizeof(STRUCT_STANDARD_TARGET))));
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assert(strcmp(h->info.name, h->entries.name) == 0);
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i = 0; n = 0;
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was_return = 0;
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/* Check all the entries. */
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ENTRY_ITERATE(h->entries.entrytable, h->entries.size,
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check_entry, &i, &n, user_offset, &was_return, h);
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assert(i == h->new_number);
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assert(n == h->entries.size);
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/* Final entry must be error node */
|
assert(strcmp(GET_TARGET(index2entry(h, h->new_number-1))
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->u.user.name,
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ERROR_TARGET) == 0);
|
}
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#endif /*IPTC_DEBUG*/
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#endif
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