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436 lines
13 KiB
436 lines
13 KiB
/* 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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#include <arpa/inet.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/libip6tc.h" |
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#define HOOK_PRE_ROUTING NF_IP6_PRE_ROUTING |
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#define HOOK_LOCAL_IN NF_IP6_LOCAL_IN |
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#define HOOK_FORWARD NF_IP6_FORWARD |
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#define HOOK_LOCAL_OUT NF_IP6_LOCAL_OUT |
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#define HOOK_POST_ROUTING NF_IP6_POST_ROUTING |
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#define STRUCT_ENTRY_TARGET struct xt_entry_target |
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#define STRUCT_ENTRY struct ip6t_entry |
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#define STRUCT_ENTRY_MATCH struct xt_entry_match |
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#define STRUCT_GETINFO struct ip6t_getinfo |
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#define STRUCT_GET_ENTRIES struct ip6t_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 ip6t_replace |
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#define ENTRY_ITERATE IP6T_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 ip6t_get_target |
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#define ERROR_TARGET XT_ERROR_TARGET |
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#define NUMHOOKS NF_IP6_NUMHOOKS |
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#define IPT_CHAINLABEL xt_chainlabel |
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#define TC_DUMP_ENTRIES dump_entries6 |
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#define TC_IS_CHAIN ip6tc_is_chain |
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#define TC_FIRST_CHAIN ip6tc_first_chain |
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#define TC_NEXT_CHAIN ip6tc_next_chain |
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#define TC_FIRST_RULE ip6tc_first_rule |
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#define TC_NEXT_RULE ip6tc_next_rule |
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#define TC_GET_TARGET ip6tc_get_target |
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#define TC_BUILTIN ip6tc_builtin |
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#define TC_GET_POLICY ip6tc_get_policy |
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#define TC_INSERT_ENTRY ip6tc_insert_entry |
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#define TC_REPLACE_ENTRY ip6tc_replace_entry |
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#define TC_APPEND_ENTRY ip6tc_append_entry |
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#define TC_CHECK_ENTRY ip6tc_check_entry |
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#define TC_DELETE_ENTRY ip6tc_delete_entry |
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#define TC_DELETE_NUM_ENTRY ip6tc_delete_num_entry |
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#define TC_FLUSH_ENTRIES ip6tc_flush_entries |
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#define TC_ZERO_ENTRIES ip6tc_zero_entries |
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#define TC_ZERO_COUNTER ip6tc_zero_counter |
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#define TC_READ_COUNTER ip6tc_read_counter |
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#define TC_SET_COUNTER ip6tc_set_counter |
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#define TC_CREATE_CHAIN ip6tc_create_chain |
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#define TC_GET_REFERENCES ip6tc_get_references |
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#define TC_DELETE_CHAIN ip6tc_delete_chain |
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#define TC_RENAME_CHAIN ip6tc_rename_chain |
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#define TC_SET_POLICY ip6tc_set_policy |
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#define TC_GET_RAW_SOCKET ip6tc_get_raw_socket |
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#define TC_INIT ip6tc_init |
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#define TC_FREE ip6tc_free |
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#define TC_COMMIT ip6tc_commit |
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#define TC_STRERROR ip6tc_strerror |
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#define TC_NUM_RULES ip6tc_num_rules |
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#define TC_GET_RULE ip6tc_get_rule |
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#define TC_OPS ip6tc_ops |
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#define TC_AF AF_INET6 |
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#define TC_IPPROTO IPPROTO_IPV6 |
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#define SO_SET_REPLACE IP6T_SO_SET_REPLACE |
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#define SO_SET_ADD_COUNTERS IP6T_SO_SET_ADD_COUNTERS |
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#define SO_GET_INFO IP6T_SO_GET_INFO |
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#define SO_GET_ENTRIES IP6T_SO_GET_ENTRIES |
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#define SO_GET_VERSION IP6T_SO_GET_VERSION |
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#define STANDARD_TARGET XT_STANDARD_TARGET |
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#define LABEL_RETURN IP6TC_LABEL_RETURN |
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#define LABEL_ACCEPT IP6TC_LABEL_ACCEPT |
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#define LABEL_DROP IP6TC_LABEL_DROP |
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#define LABEL_QUEUE IP6TC_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 BIT6(a, l) \ |
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((ntohl(a->s6_addr32[(l) / 32]) >> (31 - ((l) & 31))) & 1) |
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static int |
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ipv6_prefix_length(const struct in6_addr *a) |
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{ |
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int l, i; |
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for (l = 0; l < 128; l++) { |
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if (BIT6(a, l) == 0) |
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break; |
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} |
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for (i = l + 1; i < 128; i++) { |
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if (BIT6(a, i) == 1) |
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return -1; |
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} |
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return l; |
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} |
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static int |
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dump_entry(struct ip6t_entry *e, struct xtc_handle *const handle) |
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{ |
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size_t i; |
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char buf[40]; |
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int len; |
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struct xt_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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puts("SRC IP: "); |
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inet_ntop(AF_INET6, &e->ipv6.src, buf, sizeof buf); |
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puts(buf); |
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putchar('/'); |
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len = ipv6_prefix_length(&e->ipv6.smsk); |
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if (len != -1) |
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printf("%d", len); |
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else { |
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inet_ntop(AF_INET6, &e->ipv6.smsk, buf, sizeof buf); |
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puts(buf); |
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} |
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putchar('\n'); |
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puts("DST IP: "); |
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inet_ntop(AF_INET6, &e->ipv6.dst, buf, sizeof buf); |
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puts(buf); |
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putchar('/'); |
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len = ipv6_prefix_length(&e->ipv6.dmsk); |
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if (len != -1) |
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printf("%d", len); |
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else { |
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inet_ntop(AF_INET6, &e->ipv6.dmsk, buf, sizeof buf); |
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puts(buf); |
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} |
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putchar('\n'); |
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printf("Interface: `%s'/", e->ipv6.iniface); |
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for (i = 0; i < IFNAMSIZ; i++) |
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printf("%c", e->ipv6.iniface_mask[i] ? 'X' : '.'); |
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printf("to `%s'/", e->ipv6.outiface); |
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for (i = 0; i < IFNAMSIZ; i++) |
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printf("%c", e->ipv6.outiface_mask[i] ? 'X' : '.'); |
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printf("\nProtocol: %u\n", e->ipv6.proto); |
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if (e->ipv6.flags & IP6T_F_TOS) |
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printf("TOS: %u\n", e->ipv6.tos); |
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printf("Flags: %02X\n", e->ipv6.flags); |
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printf("Invflags: %02X\n", e->ipv6.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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IP6T_MATCH_ITERATE(e, print_match); |
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t = ip6t_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, XT_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 == XT_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, |
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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 (memcmp(&a->ipv6.src, &b->ipv6.src, sizeof(struct in6_addr)) |
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|| memcmp(&a->ipv6.dst, &b->ipv6.dst, sizeof(struct in6_addr)) |
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|| memcmp(&a->ipv6.smsk, &b->ipv6.smsk, sizeof(struct in6_addr)) |
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|| memcmp(&a->ipv6.dmsk, &b->ipv6.dmsk, sizeof(struct in6_addr)) |
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|| a->ipv6.proto != b->ipv6.proto |
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|| a->ipv6.tos != b->ipv6.tos |
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|| a->ipv6.flags != b->ipv6.flags |
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|| a->ipv6.invflags != b->ipv6.invflags) |
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return NULL; |
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for (i = 0; i < IFNAMSIZ; i++) { |
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if (a->ipv6.iniface_mask[i] != b->ipv6.iniface_mask[i]) |
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return NULL; |
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if ((a->ipv6.iniface[i] & a->ipv6.iniface_mask[i]) |
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!= (b->ipv6.iniface[i] & b->ipv6.iniface_mask[i])) |
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return NULL; |
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if (a->ipv6.outiface_mask[i] != b->ipv6.outiface_mask[i]) |
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return NULL; |
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if ((a->ipv6.outiface[i] & a->ipv6.outiface_mask[i]) |
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!= (b->ipv6.outiface[i] & b->ipv6.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 (IP6T_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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/* All zeroes == unconditional rule. */ |
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static inline int |
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unconditional(const struct ip6t_ip6 *ipv6) |
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{ |
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unsigned int i; |
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for (i = 0; i < sizeof(*ipv6); i++) |
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if (((char *)ipv6)[i]) |
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break; |
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return (i == sizeof(*ipv6)); |
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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_IP6_LOCAL_IN |
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| 1 << NF_IP6_FORWARD |
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| 1 << NF_IP6_LOCAL_OUT)); |
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/* Hooks should be first three */ |
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assert(h->info.hook_entry[NF_IP6_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_IP6_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_IP6_LOCAL_OUT] == n); |
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user_offset = h->info.hook_entry[NF_IP6_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_IP6_PRE_ROUTING |
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| 1 << NF_IP6_LOCAL_OUT |
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| 1 << NF_IP6_POST_ROUTING)) || |
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(h->info.valid_hooks |
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== (1 << NF_IP6_PRE_ROUTING |
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| 1 << NF_IP6_LOCAL_IN |
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| 1 << NF_IP6_LOCAL_OUT |
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| 1 << NF_IP6_POST_ROUTING))); |
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assert(h->info.hook_entry[NF_IP6_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_IP6_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_IP6_LOCAL_OUT] == n); |
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user_offset = h->info.hook_entry[NF_IP6_LOCAL_OUT]; |
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if (h->info.valid_hooks & (1 << NF_IP6_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_IP6_LOCAL_IN] == n); |
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user_offset = h->info.hook_entry[NF_IP6_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_IP6_PRE_ROUTING |
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| 1 << NF_IP6_LOCAL_OUT)) || |
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(h->info.valid_hooks |
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== (1 << NF_IP6_PRE_ROUTING |
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| 1 << NF_IP6_LOCAL_IN |
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| 1 << NF_IP6_FORWARD |
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| 1 << NF_IP6_LOCAL_OUT |
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| 1 << NF_IP6_POST_ROUTING))); |
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/* Hooks should be first five */ |
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assert(h->info.hook_entry[NF_IP6_PRE_ROUTING] == 0); |
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n = get_chain_end(h, 0); |
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if (h->info.valid_hooks & (1 << NF_IP6_LOCAL_IN)) { |
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n += get_entry(h, n)->next_offset; |
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assert(h->info.hook_entry[NF_IP6_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_IP6_FORWARD)) { |
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n += get_entry(h, n)->next_offset; |
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assert(h->info.hook_entry[NF_IP6_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_IP6_LOCAL_OUT] == n); |
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user_offset = h->info.hook_entry[NF_IP6_LOCAL_OUT]; |
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if (h->info.valid_hooks & (1 << NF_IP6_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_IP6_POST_ROUTING] == n); |
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user_offset = h->info.hook_entry[NF_IP6_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_IP6_PRE_ROUTING |
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| 1 << NF_IP6_LOCAL_OUT)); |
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/* Hooks should be first three */ |
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assert(h->info.hook_entry[NF_IP6_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_IP6_LOCAL_OUT] == n); |
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user_offset = h->info.hook_entry[NF_IP6_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->ipv6)); |
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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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printf("target_size=%u, align=%u\n", |
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t->target.u.target_size, ALIGN(sizeof(*t))); |
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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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iptcb_entry2index(h, get_entry(h, h->info.hook_entry[i])); |
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iptcb_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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#if 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 */ |
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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 |
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} |
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#endif /*IPTC_DEBUG*/
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