How to use swift convert string to ipv6 addr - swift

Question

I have a ipv6 string,how to use Swift convert to in6_addr
let ipString = "2001:0b28:f23f:f005:0000:0000:0000:000a"

Answer 1

You can use inet_pton()
similarly as you would in a C program:
let ipString = "2001:0b28:f23f:f005:0000:0000:0000:000a"
var addr = in6_addr()
let retval = withUnsafeMutablePointer(&addr) {
inet_pton(AF_INET6, ipString, UnsafeMutablePointer($0))
}
if retval == 0 {
print("Invalid address")
} else if retval == -1 {
print("Failed:", String.fromCString(strerror(errno)) ?? "\(errno)")
// For Swift 3, replace the last line by
// print("Failed:", String(cString: strerror(errno)))
} else {
// Success, `addr` contains the result.
}
withUnsafeMutablePointer() is necessary to pass the address of
the addr variable to inet_pton().

Answer 2

Swift 5 & Network
You can use IPv6Address from Network to work with IPv6 addresses. It is useful for working with local or remote endpoints NWEndpoints, for validating string IPv6 addresses, shortening etc.
There is a extension of IPv6Address that implements helper functions for in6_addr:
import Network
extension IPv6Address {
var address: in6_addr {
rawValue.withUnsafeBytes {
$0.load(as: in6_addr.self)
}
}
var stringValue: String { debugDescription }
init(_ address: in6_addr) {
var addr = address
let data = withUnsafeBytes(of: &addr) { Data($0) }
self.init(data)!
}
}
How to use:
let ipString = "2001:0b28:f23f:f005:0000:0000:0000:000a"
// Create IPv6Address from string
if let ipv6 = IPv6Address(ipString) {
// Get in6_addr from IPv6Address
let addr = ipv6.address
print(addr) // in6_addr(__u6_addr: __C.in6_addr.__Unnamed_union___u6_addr())
// Create IPv6Address from in6_addr
let ipv6 = IPv6Address(addr)
print(ipv6.stringValue) // 2001:b28:f23f:f005::a
}