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      1 /*
      2  * Copyright (C) 2014 The Android Open Source Project
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  *  * Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  *  * Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in
     12  *    the documentation and/or other materials provided with the
     13  *    distribution.
     14  *
     15  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     16  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     17  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
     18  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
     19  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
     20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
     21  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
     22  * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
     23  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
     25  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     26  * SUCH DAMAGE.
     27  */
     28 #ifndef _RESOLV_NETID_H
     29 #define _RESOLV_NETID_H
     30 
     31 /* This header contains declarations related to per-network DNS
     32  * server selection. They are used by system/netd/ and should not be
     33  * exposed by the C library's public NDK headers.
     34  */
     35 #include <sys/cdefs.h>
     36 #include <netinet/in.h>
     37 #include <stdio.h>
     38 
     39 /*
     40  * Passing NETID_UNSET as the netId causes system/netd/server/DnsProxyListener.cpp to
     41  * fill in the appropriate default netId for the query.
     42  */
     43 #define NETID_UNSET 0u
     44 
     45 /*
     46  * MARK_UNSET represents the default (i.e. unset) value for a socket mark.
     47  */
     48 #define MARK_UNSET 0u
     49 
     50 __BEGIN_DECLS
     51 
     52 struct __res_params;
     53 struct addrinfo;
     54 
     55 #define __used_in_netd __attribute__((visibility ("default")))
     56 
     57 /*
     58  * A struct to capture context relevant to network operations.
     59  *
     60  * Application and DNS netids/marks can differ from one another under certain
     61  * circumstances, notably when a VPN applies to the given uid's traffic but the
     62  * VPN network does not have its own DNS servers explicitly provisioned.
     63  *
     64  * The introduction of per-UID routing means the uid is also an essential part
     65  * of the evaluation context. Its proper uninitialized value is
     66  * NET_CONTEXT_INVALID_UID.
     67  */
     68 struct android_net_context {
     69     unsigned app_netid;
     70     unsigned app_mark;
     71     unsigned dns_netid;
     72     unsigned dns_mark;
     73     uid_t uid;
     74 } __attribute__((packed));
     75 
     76 #define NET_CONTEXT_INVALID_UID ((uid_t)-1)
     77 
     78 struct hostent *android_gethostbyaddrfornet(const void *, socklen_t, int, unsigned, unsigned) __used_in_netd;
     79 struct hostent *android_gethostbynamefornet(const char *, int, unsigned, unsigned) __used_in_netd;
     80 int android_getaddrinfofornet(const char *, const char *, const struct addrinfo *, unsigned,
     81     unsigned, struct addrinfo **) __used_in_netd;
     82 /*
     83  * TODO: consider refactoring android_getaddrinfo_proxy() to serve as an
     84  * explore_fqdn() dispatch table method, with the below function only making DNS calls.
     85  */
     86 int android_getaddrinfofornetcontext(const char *, const char *, const struct addrinfo *,
     87     const struct android_net_context *, struct addrinfo **) __used_in_netd;
     88 
     89 /* set name servers for a network */
     90 extern int _resolv_set_nameservers_for_net(unsigned netid, const char** servers,
     91         unsigned numservers, const char *domains, const struct __res_params* params) __used_in_netd;
     92 
     93 /* flush the cache associated with a certain network */
     94 extern void _resolv_flush_cache_for_net(unsigned netid) __used_in_netd;
     95 
     96 /* delete the cache associated with a certain network */
     97 extern void _resolv_delete_cache_for_net(unsigned netid) __used_in_netd;
     98 
     99 /* Internal use only. */
    100 struct hostent *android_gethostbyaddrfornet_proxy(const void *, socklen_t, int , unsigned, unsigned) __LIBC_HIDDEN__;
    101 int android_getnameinfofornet(const struct sockaddr *, socklen_t, char *, size_t, char *, size_t, int, unsigned, unsigned) __LIBC_HIDDEN__;
    102 FILE* android_open_proxy(void) __LIBC_HIDDEN__;
    103 
    104 /* delete the cache associated with a certain network */
    105 extern void _resolv_delete_cache_for_net(unsigned netid);
    106 
    107 __END_DECLS
    108 
    109 #endif /* _RESOLV_NETID_H */
    110