initial

internal/restrictednet/client.go

@@ -0,0 +1,56 @@
+package restrictednet
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+
+	"github.com/qdm12/dns/v2/pkg/provider"
+)
+
+// Client is a client for making restricted network requests,
+// such as opening temporary firewall rules for HTTPS connections.
+// It is not meant to be high performance, although it can be used for
+// multiple requests and concurrently.
+type Client struct {
+	ipv6Supported     bool
+	firewall          Firewall
+	outboundInterface string
+	dohServers        []provider.DoHServer
+}
+
+func New(firewall Firewall, defaultInterface string, ipv6Supported bool,
+	upstreamResolvers []provider.Provider,
+) (*Client, error) {
+	dohServers := make([]provider.DoHServer, len(upstreamResolvers))
+	for i, upstreamResolver := range upstreamResolvers {
+		dohServers[i] = upstreamResolver.DoH
+	}
+
+	return &Client{
+		firewall:          firewall,
+		outboundInterface: defaultInterface,
+		ipv6Supported:     ipv6Supported,
+		dohServers:        dohServers,
+	}, nil
+}
+
+func (c *Client) OpenHTTPSByDomain(ctx context.Context, domain string) (
+	httpClient *http.Client, cleanup func() error, err error,
+) {
+	resolvedIPs, err := c.ResolveName(ctx, domain)
+	if err != nil {
+		return nil, nil, fmt.Errorf("resolving name: %w", err)
+	} else if len(resolvedIPs) == 0 {
+		return nil, nil, fmt.Errorf("no IP address found for name %q", domain)
+	}
+
+	selectedIP := resolvedIPs[0]
+
+	httpClient, cleanup, err = c.OpenHTTPS(domain, selectedIP)
+	if err != nil {
+		return nil, nil, fmt.Errorf("opening HTTPS: %w", err)
+	}
+
+	return httpClient, cleanup, nil
+}