143 lines
3.6 KiB
Go
143 lines
3.6 KiB
Go
package netutil
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import (
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"net"
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"net/url"
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"strconv"
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"strings"
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)
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// addrsFromNodes takes a list of node hosts and attempts to return a list of hosts in ip:port
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// format along with any error encountered.
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//
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// The function accepts node hosts in URL, ip, ip:port, resolvable-name and resolvable-name:port
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// formats and will append the default port value if needed.
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func addrsFromNodes(nodes []string) ([]string, error) {
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var addrs []string
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for _, n := range nodes {
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switch {
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// Assume that the node is provided as a URL
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case strings.Contains(n, "://"):
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newAddrs, err := parseURL(n)
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if err != nil {
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return nil, newInvalidNodeError(err)
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}
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addrs = append(addrs, newAddrs...)
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// Assume the node is in hostname:port or ip:port format
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case strings.Contains(n, ":"):
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newAddrs, err := parseHostPort(n)
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if err != nil {
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return nil, newInvalidNodeError(err)
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}
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addrs = append(addrs, newAddrs...)
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// Assume hostname or ip
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default:
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newAddrs, err := parseHost(n)
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if err != nil {
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return nil, newInvalidNodeError(err)
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}
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addrs = append(addrs, newAddrs...)
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}
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}
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return addrs, nil
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}
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func validPort(port string) bool {
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intPort, err := strconv.Atoi(port)
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return (err == nil) &&
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(intPort > 0) &&
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(intPort <= 65535)
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}
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// parseURL takes a valid URL and verifies that it is using a correct scheme, has a resolvable
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// address (or is an IP) and has a valid port (or adds the default if the port is omitted). The
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// function then returns a list of addresses in ip:port format along with any error encountered.
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//
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// The function may return multiple addresses depending on the dns answer received when resolving
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// the host.
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func parseURL(node string) ([]string, error) {
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url, err := url.Parse(node)
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if err != nil {
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return nil, err
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}
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// Verify a valid scheme
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switch url.Scheme {
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case "tcp", "http", "https":
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host, port, err := net.SplitHostPort(url.Host)
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if err != nil {
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// We could be here as there is no port, lets try one last time with default port added
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host, port, err = net.SplitHostPort(url.Host + ":" + DefaultDialPort)
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if err != nil {
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return nil, err
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}
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}
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if !validPort(port) {
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return nil, errInvalidPortNumber
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}
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// LookupHost works for IP addr too
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addrs, err := net.LookupHost(host)
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if err != nil {
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return nil, err
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}
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for i, a := range addrs {
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addrs[i] = a + ":" + port
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}
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return addrs, nil
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default:
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return nil, errUnsupportedScheme
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}
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}
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// parseHostPort takes a string in host:port format and checks it has a resolvable address (or is
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// an IP) and a valid port (or adds the default if the port is omitted). The function then returns
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// a list of addresses in ip:port format along with any error encountered.
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//
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// The function may return multiple addresses depending on the dns answer received when resolving
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// the host.
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func parseHostPort(node string) ([]string, error) {
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host, port, err := net.SplitHostPort(node)
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if err != nil {
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return nil, err
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}
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if !validPort(port) {
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return nil, errInvalidPortNumber
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}
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// LookupHost works for IP addr too
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addrs, err := net.LookupHost(host)
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if err != nil {
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return nil, err
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}
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for i, a := range addrs {
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addrs[i] = a + ":" + port
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}
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return addrs, nil
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}
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// parseHostPort takes a hostname string and checks it is resolvable to an address (or is already
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// an IP) The function then returns a list of addresses in ip:port format (where port is the
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// default port) along with any error encountered.
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//
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// The function may return multiple addresses depending on the dns answer received when resolving
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// the host.
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func parseHost(node string) ([]string, error) {
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return parseHostPort(node + ":" + DefaultDialPort)
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}
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