I can use the code below to get the IPv4 DNS address. With the IPv6 DNS address, res_ninit() cannot parse the IPv6 address. For example, iOS - Get the device’s DNS server address only on the IPv6 network , sin_family always AF_UNSPEC .
Are there any other solutions to get the IPv6 DNS address? Thanks for the help.
+ (void)outPutDNSServers { res_state res = malloc(sizeof(struct __res_state)); int result = res_ninit(res); if ( result == 0 ) { for ( int i = 0; i < res->nscount; i++ ) { NSString *s = [NSString stringWithUTF8String : inet_ntoa(res->nsaddr_list[i].sin_addr)]; NSLog(@"%@",s); } } else { NSLog(@"%@",@" res_init result != 0"); } res_nclose(res); }
Edit:
I have already solved the problem as shown below.
+ (void)outPutDNSServers { res_state res = malloc(sizeof(struct __res_state)); int result = res_ninit(res); if (result == 0) { union res_9_sockaddr_union *addr_union = malloc(res->nscount * sizeof(union res_9_sockaddr_union)); res_getservers(res, addr_union, res->nscount); for (int i = 0; i < res->nscount; i++) { if (addr_union[i].sin.sin_family == AF_INET) { char ip[INET_ADDRSTRLEN]; inet_ntop(AF_INET, &(addr_union[i].sin.sin_addr), ip, INET_ADDRSTRLEN); NSString *dnsIP = [NSString stringWithUTF8String:ip]; NSLog(@"IPv4 DNS IP: %@", dnsIP); } else if (addr_union[i].sin6.sin6_family == AF_INET6) { char ip[INET6_ADDRSTRLEN]; inet_ntop(AF_INET6, &(addr_union[i].sin6.sin6_addr), ip, INET6_ADDRSTRLEN); NSString *dnsIP = [NSString stringWithUTF8String:ip]; NSLog(@"IPv6 DNS IP: %@", dnsIP); } else { NSLog(@"Undefined family."); } } } res_nclose(res);
}
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