libfetch: fix connection pooling for proxied http/https requests

The connection pooling was broken in two ways:

 1. The original URL was always used as the connection pool URL,
    resulting in duplicate connections to the proxy for http URLs
    (each http URL would get separate proxy connection)

 2. The cache_url stored was always the socket level connect URL.
    In case of HTTPS, the lookup was done done with the real URL,
    but the proxy URL was stored as the "cache URL". Thus HTTPS
    CONNECT connections were never re-used.

This fixes the code with following logic:

 1. The cache key url is the real URL when no-proxy, or when HTTPS
    with proxy (the socket is connected to proxy, but logically it
    is connected to the real URL due to HTTP CONNECT request).
    And for HTTP with proxy, it's the proxy URL so same proxy
    connection can be reused for all requests going through it.

 2. fetch_connect() now gets cache key URL separately, and it always
    gets the same value as the fetch_cache_get() calls.

1 files changed, 2 insertions, 2 deletions

diff --git a/libfetch/common.c b/libfetch/common.c
index aabe218..e91b0c6 100644
--- a/libfetch/common.c
+++ b/libfetch/common.c
@@ -251,7 +251,7 @@ fetch_bind(int sd, int af, const char *addr)
  * Establish a TCP connection to the specified port on the specified host.
  */
 conn_t *
-fetch_connect(struct url *url, int af, int verbose)
+fetch_connect(struct url *cache_url, struct url *url, int af, int verbose)
 {
 	conn_t *conn;
 	char pbuf[10];
@@ -303,7 +303,7 @@ fetch_connect(struct url *url, int af, int verbose)
 		close(sd);
 		return (NULL);
 	}
-	conn->cache_url = fetchCopyURL(url);
+	conn->cache_url = fetchCopyURL(cache_url);
 	conn->cache_af = af;
 	return (conn);
 }