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a7ae21d685
Check that the node ann doesnt contain more than 1 DNS addr. This will ensure that we now start rejecting new node announcements with multiple DNS addrs since this check is called in the gossiper before persisting a node ann to our local graph. It also validates the DNS fields according to BOLT #7 specs.
77 lines
2.1 KiB
Go
77 lines
2.1 KiB
Go
package lnwire
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import (
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"errors"
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"fmt"
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"net"
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"strconv"
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)
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// ErrEmptyDNSHostname is returned when a DNS hostname is empty.
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var ErrEmptyDNSHostname = errors.New("hostname cannot be empty")
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// ErrZeroPort is returned when a DNS port is zero.
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var ErrZeroPort = errors.New("port cannot be zero")
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// DNSAddress is used to represent a DNS address of a node.
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type DNSAddress struct {
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// Hostname is the DNS hostname of the address. This MUST only contain
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// ASCII characters as per Bolt #7. The maximum length that this may
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// be is 255 bytes.
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Hostname string
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// Port is the port number of the address.
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Port uint16
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}
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// A compile-time check to ensure that DNSAddress implements the net.Addr
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// interface.
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var _ net.Addr = (*DNSAddress)(nil)
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// Network returns the network that this address uses, which is "tcp".
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func (d *DNSAddress) Network() string {
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return "tcp"
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}
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// String returns the address in the form "hostname:port".
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func (d *DNSAddress) String() string {
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return net.JoinHostPort(d.Hostname, strconv.Itoa(int(d.Port)))
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}
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// ValidateDNSAddr validates that the DNS hostname is not empty and contains
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// only ASCII characters and of max length 255 characters and port is non zero
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// according to BOLT #7.
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func ValidateDNSAddr(hostname string, port uint16) error {
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if hostname == "" {
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return ErrEmptyDNSHostname
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}
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// Per BOLT 7, ports must not be zero for type 5 address (DNS address).
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if port == 0 {
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return ErrZeroPort
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}
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if len(hostname) > 255 {
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return fmt.Errorf("DNS hostname length %d, exceeds limit of "+
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"255 bytes", len(hostname))
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}
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// Check if hostname contains only ASCII characters.
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for i, r := range hostname {
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// Check for valid hostname characters, excluding ASCII control
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// characters (0-31), spaces, underscores, delete character
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// (127), and the special characters (like /, \, @, #, $, etc.).
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if !((r >= 'a' && r <= 'z') ||
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(r >= 'A' && r <= 'Z') ||
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(r >= '0' && r <= '9') ||
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r == '-' ||
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r == '.') {
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return fmt.Errorf("hostname '%s' contains invalid "+
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"character '%c' at position %d", hostname, r, i)
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}
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}
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return nil
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}
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