1 files changed, 50 insertions, 0 deletions
diff --git a/daemon/proxyv2.h b/daemon/proxyv2.h
new file mode 100644
index 0000000..2d57744
--- /dev/null
+++ b/daemon/proxyv2.h
@@ -0,0 +1,50 @@
+/*  Copyright (C) CZ.NIC, z.s.p.o. <knot-resolver@labs.nic.cz>
+ *  SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+#include "daemon/session.h"
+#include "daemon/network.h"
+#include "lib/utils.h"
+
+extern const char PROXY2_SIGNATURE[12];
+
+#define PROXY2_MIN_SIZE 16
+
+enum proxy2_command {
+	PROXY2_CMD_LOCAL = 0x0,
+	PROXY2_CMD_PROXY = 0x1
+};
+
+/** Parsed result of the PROXY protocol */
+struct proxy_result {
+	enum proxy2_command command;  /**< Proxy command - PROXY or LOCAL. */
+	int family;                   /**< Address family from netinet library (e.g. AF_INET6). */
+	int protocol;                 /**< Protocol type from socket library (e.g. SOCK_STREAM). */
+	union kr_sockaddr src_addr;   /**< Parsed source address and port. */
+	union kr_sockaddr dst_addr;   /**< Parsed destination address and port. */
+	bool has_tls : 1;             /**< `true` = client has used TLS with the proxy.
+	                                   If TLS padding is enabled, it will be used even if
+	                                   the proxy did not use TLS with kresd. */
+};
+
+/** Checks for a PROXY protocol version 2 signature in the specified buffer. */
+static inline bool proxy_header_present(const void* buf, const ssize_t nread)
+{
+	return nread >= PROXY2_MIN_SIZE &&
+		memcmp(buf, PROXY2_SIGNATURE, sizeof(PROXY2_SIGNATURE)) == 0;
+}
+
+/** Checks whether the use of PROXYv2 protocol is allowed for the specified
+ * address. */
+bool proxy_allowed(const struct network *net, const struct sockaddr *saddr);
+
+/** Parses the PROXYv2 header from buf of size nread and writes the result into
+ * out. The rest of the buffer is moved to free bytes of the specified session's
+ * wire buffer. The function assumes that the PROXYv2 signature is present
+ * and has been already checked by the caller (like `udp_recv` or `tcp_recv`). */
+ssize_t proxy_process_header(struct proxy_result *out, struct session *s,
+                             const void *buf, ssize_t nread);