1890549 - nsHttpChannel implementation DNS resolve strategy for proxies incomplete

Status: NEW

(Core :: Networking: Proxy, task, P3)

Description

[Manuel Bucher [:manuel] {{ FYI: OOO until 6 October }}]

We have several flags:

Only DNS_PREFETCH_ORIGIN is ever set from the following flags:

netwerk/protocol/http/nsHttpChannel.h#308-317

// Tells the channel to resolve the origin of the end server we are connecting
// to.
static uint16_t const DNS_PREFETCH_ORIGIN = 1 << 0;
// Tells the channel to resolve the host name of the proxy.
static uint16_t const DNS_PREFETCH_PROXY = 1 << 1;
// Will be set if the current channel uses an HTTP/HTTPS proxy.
static uint16_t const DNS_PROXY_IS_HTTP = 1 << 2;
// Tells the channel to wait for the result of the origin server resolution
// before any connection attempts are made.
static uint16_t const DNS_BLOCK_ON_ORIGIN_RESOLVE = 1 << 3;

These two are never set:

• DNS_PREFETCH_PROXY
• DNS_PROXY_IS_HTTP

DNS_BLOCK_ON_ORIGIN_RESOLVE is read (and may be assumed to be set. Code for this was introduced in Bug 1600965, but is apparently still dead code.

netwerk/protocol/http/nsHttpChannel.cpp#6362-6364 contains the relevant TODO in mozilla-central:

uint16_t nsHttpChannel::GetProxyDNSStrategy() {
  // This function currently only supports returning DNS_PREFETCH_ORIGIN.
  // Support for the rest of the DNS_* flags will be added later.