501 lines
11 KiB
C
501 lines
11 KiB
C
/* $OpenBSD: addrmatch.c,v 1.6 2012/06/21 00:16:07 dtucker Exp $ */
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/*
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* Copyright (c) 2004-2008 Damien Miller <djm@mindrot.org>
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*
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* Permission to use, copy, modify, and distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "includes.h"
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#include <sys/types.h>
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#include <sys/socket.h>
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#include <netinet/in.h>
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#include <arpa/inet.h>
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#include <netdb.h>
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#include <string.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <stdarg.h>
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#include "match.h"
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#include "log.h"
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#include "xmalloc.h"
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struct xaddr {
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sa_family_t af;
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union {
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struct in_addr v4;
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struct in6_addr v6;
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u_int8_t addr8[16];
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u_int32_t addr32[4];
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} xa; /* 128-bit address */
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u_int32_t scope_id; /* iface scope id for v6 */
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#define v4 xa.v4
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#define v6 xa.v6
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#define addr8 xa.addr8
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#define addr32 xa.addr32
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};
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static int
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addr_unicast_masklen(int af)
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{
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switch (af) {
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case AF_INET:
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return 32;
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case AF_INET6:
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return 128;
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default:
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return -1;
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}
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}
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static inline int
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masklen_valid(int af, u_int masklen)
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{
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switch (af) {
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case AF_INET:
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return masklen <= 32 ? 0 : -1;
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case AF_INET6:
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return masklen <= 128 ? 0 : -1;
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default:
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return -1;
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}
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}
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/*
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* Convert struct sockaddr to struct xaddr
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* Returns 0 on success, -1 on failure.
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*/
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static int
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addr_sa_to_xaddr(struct sockaddr *sa, socklen_t slen, struct xaddr *xa)
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{
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struct sockaddr_in *in4 = (struct sockaddr_in *)sa;
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struct sockaddr_in6 *in6 = (struct sockaddr_in6 *)sa;
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memset(xa, '\0', sizeof(*xa));
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switch (sa->sa_family) {
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case AF_INET:
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if (slen < sizeof(*in4))
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return -1;
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xa->af = AF_INET;
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memcpy(&xa->v4, &in4->sin_addr, sizeof(xa->v4));
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break;
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case AF_INET6:
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if (slen < sizeof(*in6))
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return -1;
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xa->af = AF_INET6;
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memcpy(&xa->v6, &in6->sin6_addr, sizeof(xa->v6));
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#ifdef HAVE_STRUCT_SOCKADDR_IN6_SIN6_SCOPE_ID
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xa->scope_id = in6->sin6_scope_id;
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#endif
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break;
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default:
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return -1;
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}
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return 0;
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}
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/*
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* Calculate a netmask of length 'l' for address family 'af' and
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* store it in 'n'.
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* Returns 0 on success, -1 on failure.
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*/
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static int
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addr_netmask(int af, u_int l, struct xaddr *n)
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{
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int i;
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if (masklen_valid(af, l) != 0 || n == NULL)
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return -1;
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memset(n, '\0', sizeof(*n));
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switch (af) {
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case AF_INET:
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n->af = AF_INET;
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if (l == 0)
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return 0;
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n->v4.s_addr = htonl((0xffffffff << (32 - l)) & 0xffffffff);
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return 0;
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case AF_INET6:
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n->af = AF_INET6;
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for (i = 0; i < 4 && l >= 32; i++, l -= 32)
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n->addr32[i] = 0xffffffffU;
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if (i < 4 && l != 0)
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n->addr32[i] = htonl((0xffffffff << (32 - l)) &
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0xffffffff);
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return 0;
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default:
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return -1;
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}
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}
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/*
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* Perform logical AND of addresses 'a' and 'b', storing result in 'dst'.
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* Returns 0 on success, -1 on failure.
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*/
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static int
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addr_and(struct xaddr *dst, const struct xaddr *a, const struct xaddr *b)
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{
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int i;
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if (dst == NULL || a == NULL || b == NULL || a->af != b->af)
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return -1;
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memcpy(dst, a, sizeof(*dst));
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switch (a->af) {
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case AF_INET:
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dst->v4.s_addr &= b->v4.s_addr;
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return 0;
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case AF_INET6:
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dst->scope_id = a->scope_id;
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for (i = 0; i < 4; i++)
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dst->addr32[i] &= b->addr32[i];
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return 0;
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default:
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return -1;
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}
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}
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/*
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* Compare addresses 'a' and 'b'
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* Return 0 if addresses are identical, -1 if (a < b) or 1 if (a > b)
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*/
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static int
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addr_cmp(const struct xaddr *a, const struct xaddr *b)
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{
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int i;
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if (a->af != b->af)
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return a->af == AF_INET6 ? 1 : -1;
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switch (a->af) {
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case AF_INET:
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if (a->v4.s_addr == b->v4.s_addr)
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return 0;
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return ntohl(a->v4.s_addr) > ntohl(b->v4.s_addr) ? 1 : -1;
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case AF_INET6:
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for (i = 0; i < 16; i++)
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if (a->addr8[i] - b->addr8[i] != 0)
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return a->addr8[i] > b->addr8[i] ? 1 : -1;
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if (a->scope_id == b->scope_id)
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return 0;
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return a->scope_id > b->scope_id ? 1 : -1;
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default:
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return -1;
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}
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}
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/*
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* Parse string address 'p' into 'n'
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* Returns 0 on success, -1 on failure.
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*/
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static int
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addr_pton(const char *p, struct xaddr *n)
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{
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struct addrinfo hints, *ai;
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memset(&hints, '\0', sizeof(hints));
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hints.ai_flags = AI_NUMERICHOST;
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if (p == NULL || getaddrinfo(p, NULL, &hints, &ai) != 0)
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return -1;
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if (ai == NULL || ai->ai_addr == NULL)
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return -1;
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if (n != NULL &&
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addr_sa_to_xaddr(ai->ai_addr, ai->ai_addrlen, n) == -1) {
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freeaddrinfo(ai);
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return -1;
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}
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freeaddrinfo(ai);
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return 0;
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}
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/*
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* Perform bitwise negation of address
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* Returns 0 on success, -1 on failure.
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*/
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static int
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addr_invert(struct xaddr *n)
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{
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int i;
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if (n == NULL)
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return (-1);
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switch (n->af) {
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case AF_INET:
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n->v4.s_addr = ~n->v4.s_addr;
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return (0);
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case AF_INET6:
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for (i = 0; i < 4; i++)
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n->addr32[i] = ~n->addr32[i];
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return (0);
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default:
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return (-1);
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}
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}
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/*
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* Calculate a netmask of length 'l' for address family 'af' and
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* store it in 'n'.
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* Returns 0 on success, -1 on failure.
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*/
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static int
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addr_hostmask(int af, u_int l, struct xaddr *n)
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{
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if (addr_netmask(af, l, n) == -1 || addr_invert(n) == -1)
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return (-1);
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return (0);
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}
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/*
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* Test whether address 'a' is all zeros (i.e. 0.0.0.0 or ::)
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* Returns 0 on if address is all-zeros, -1 if not all zeros or on failure.
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*/
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static int
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addr_is_all0s(const struct xaddr *a)
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{
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int i;
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switch (a->af) {
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case AF_INET:
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return (a->v4.s_addr == 0 ? 0 : -1);
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case AF_INET6:;
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for (i = 0; i < 4; i++)
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if (a->addr32[i] != 0)
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return (-1);
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return (0);
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default:
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return (-1);
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}
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}
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/*
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* Test whether host portion of address 'a', as determined by 'masklen'
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* is all zeros.
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* Returns 0 on if host portion of address is all-zeros,
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* -1 if not all zeros or on failure.
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*/
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static int
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addr_host_is_all0s(const struct xaddr *a, u_int masklen)
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{
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struct xaddr tmp_addr, tmp_mask, tmp_result;
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memcpy(&tmp_addr, a, sizeof(tmp_addr));
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if (addr_hostmask(a->af, masklen, &tmp_mask) == -1)
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return (-1);
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if (addr_and(&tmp_result, &tmp_addr, &tmp_mask) == -1)
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return (-1);
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return (addr_is_all0s(&tmp_result));
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}
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/*
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* Parse a CIDR address (x.x.x.x/y or xxxx:yyyy::/z).
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* Return -1 on parse error, -2 on inconsistency or 0 on success.
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*/
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static int
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addr_pton_cidr(const char *p, struct xaddr *n, u_int *l)
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{
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struct xaddr tmp;
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long unsigned int masklen = 999;
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char addrbuf[64], *mp, *cp;
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/* Don't modify argument */
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if (p == NULL || strlcpy(addrbuf, p, sizeof(addrbuf)) >= sizeof(addrbuf))
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return -1;
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if ((mp = strchr(addrbuf, '/')) != NULL) {
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*mp = '\0';
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mp++;
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masklen = strtoul(mp, &cp, 10);
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if (*mp == '\0' || *cp != '\0' || masklen > 128)
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return -1;
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}
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if (addr_pton(addrbuf, &tmp) == -1)
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return -1;
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if (mp == NULL)
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masklen = addr_unicast_masklen(tmp.af);
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if (masklen_valid(tmp.af, masklen) == -1)
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return -2;
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if (addr_host_is_all0s(&tmp, masklen) != 0)
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return -2;
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if (n != NULL)
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memcpy(n, &tmp, sizeof(*n));
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if (l != NULL)
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*l = masklen;
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return 0;
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}
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static int
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addr_netmatch(const struct xaddr *host, const struct xaddr *net, u_int masklen)
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{
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struct xaddr tmp_mask, tmp_result;
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if (host->af != net->af)
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return -1;
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if (addr_netmask(host->af, masklen, &tmp_mask) == -1)
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return -1;
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if (addr_and(&tmp_result, host, &tmp_mask) == -1)
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return -1;
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return addr_cmp(&tmp_result, net);
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}
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/*
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* Match "addr" against list pattern list "_list", which may contain a
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* mix of CIDR addresses and old-school wildcards.
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*
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* If addr is NULL, then no matching is performed, but _list is parsed
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* and checked for well-formedness.
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*
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* Returns 1 on match found (never returned when addr == NULL).
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* Returns 0 on if no match found, or no errors found when addr == NULL.
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* Returns -1 on negated match found (never returned when addr == NULL).
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* Returns -2 on invalid list entry.
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*/
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int
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addr_match_list(const char *addr, const char *_list)
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{
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char *list, *cp, *o;
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struct xaddr try_addr, match_addr;
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u_int masklen, neg;
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int ret = 0, r;
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if (addr != NULL && addr_pton(addr, &try_addr) != 0) {
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debug2("%s: couldn't parse address %.100s", __func__, addr);
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return 0;
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}
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if ((o = list = strdup(_list)) == NULL)
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return -1;
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while ((cp = strsep(&list, ",")) != NULL) {
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neg = *cp == '!';
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if (neg)
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cp++;
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if (*cp == '\0') {
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ret = -2;
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break;
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}
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/* Prefer CIDR address matching */
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r = addr_pton_cidr(cp, &match_addr, &masklen);
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if (r == -2) {
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error("Inconsistent mask length for "
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"network \"%.100s\"", cp);
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ret = -2;
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break;
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} else if (r == 0) {
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if (addr != NULL && addr_netmatch(&try_addr,
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&match_addr, masklen) == 0) {
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foundit:
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if (neg) {
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ret = -1;
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break;
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}
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ret = 1;
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}
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continue;
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} else {
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/* If CIDR parse failed, try wildcard string match */
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if (addr != NULL && match_pattern(addr, cp) == 1)
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goto foundit;
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}
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}
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xfree(o);
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return ret;
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}
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/*
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* Match "addr" against list CIDR list "_list". Lexical wildcards and
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* negation are not supported. If "addr" == NULL, will verify structure
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* of "_list".
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*
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* Returns 1 on match found (never returned when addr == NULL).
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* Returns 0 on if no match found, or no errors found when addr == NULL.
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* Returns -1 on error
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*/
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int
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addr_match_cidr_list(const char *addr, const char *_list)
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{
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char *list, *cp, *o;
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struct xaddr try_addr, match_addr;
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u_int masklen;
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int ret = 0, r;
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if (addr != NULL && addr_pton(addr, &try_addr) != 0) {
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debug2("%s: couldn't parse address %.100s", __func__, addr);
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return 0;
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}
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if ((o = list = strdup(_list)) == NULL)
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return -1;
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while ((cp = strsep(&list, ",")) != NULL) {
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if (*cp == '\0') {
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error("%s: empty entry in list \"%.100s\"",
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__func__, o);
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ret = -1;
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break;
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}
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/*
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* NB. This function is called in pre-auth with untrusted data,
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* so be extra paranoid about junk reaching getaddrino (via
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* addr_pton_cidr).
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*/
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/* Stop junk from reaching getaddrinfo. +3 is for masklen */
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if (strlen(cp) > INET6_ADDRSTRLEN + 3) {
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error("%s: list entry \"%.100s\" too long",
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__func__, cp);
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ret = -1;
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break;
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}
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#define VALID_CIDR_CHARS "0123456789abcdefABCDEF.:/"
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if (strspn(cp, VALID_CIDR_CHARS) != strlen(cp)) {
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error("%s: list entry \"%.100s\" contains invalid "
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"characters", __func__, cp);
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ret = -1;
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}
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/* Prefer CIDR address matching */
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r = addr_pton_cidr(cp, &match_addr, &masklen);
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if (r == -1) {
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error("Invalid network entry \"%.100s\"", cp);
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ret = -1;
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break;
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} else if (r == -2) {
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error("Inconsistent mask length for "
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"network \"%.100s\"", cp);
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ret = -1;
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break;
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} else if (r == 0 && addr != NULL) {
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if (addr_netmatch(&try_addr, &match_addr,
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masklen) == 0)
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ret = 1;
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continue;
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}
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}
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xfree(o);
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return ret;
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}
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