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Fallback to normal connection if TLS fails 

As described in document draft-ietf-dprive-dns-over-tls [1] we should fallback
to normal connection (without TLS) if there's any error with the TLS
connection.

See #297

[1] http://tools.ietf.org/html/draft-ietf-dprive-dns-over-tls-02
This commit is contained in:
Rafael Dantas Justo 2016-01-04 10:49:20 -02:00
parent ce3e1286f2
commit 124839738d
1 changed files with 18 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
client.go
View File

@ -161,6 +161,7 @@ func (c *Client) exchange(m *Msg, a string) (r *Msg, rtt time.Duration, err erro
network = c.Net
}
connect:
if c.TLS {
// TLS connection is always TCP
co, err = DialTimeoutWithTLS("tcp", a, c.TLSConfig, c.dialTimeout())
@ -168,7 +169,23 @@ func (c *Client) exchange(m *Msg, a string) (r *Msg, rtt time.Duration, err erro
co, err = DialTimeout(network, a, c.dialTimeout())
}
if err != nil {
// TODO(rafaeljusto)
//
// draft-ietf-dprive-dns-over-tls (section 3.1)
//
// DNS clients SHOULD remember server IP addresses that don't support
// DNS-over-TLS, including timeouts, connection refusals, and TLS
// handshake failures, and not request DNS-over-TLS from them for a
// reasonable period (such as one hour per server). DNS clients
// following an out-of-band key-pinned privacy profile MAY be more
// aggressive about retrying DNS-over-TLS connection failures.
if err != nil && c.TLS {
// TODO(rafaeljusto)
// Log the error somewhere or just ignore it?
c.TLS = false
goto connect
} else if err != nil {
return nil, 0, err
}
defer co.Close()