headers: add extern "C" guards for C++ interop (chatgui)

Added #ifdef __cplusplus / extern "C" { ... } / #endif to ~65 headers
in src/ and lib/, enabling the C library to be linked into C++ code (chatgui).
Fixed packet_dump.h (added missing header guard) and etcp_bbr.h
(#pragma once guard).

src/proxy/icmp_proxy.h

@@ -2,6 +2,11 @@
 #ifndef ICMP_PROXY_H
 #define ICMP_PROXY_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
 #include <stdint.h>
 #include "../lib/socket_compat.h"
 
@@ -62,4 +67,8 @@ int icmp_proxy_deliver_reply(struct UTUN_INSTANCE* inst,
 
 void icmp_proxy_set_test_loopback(struct UTUN_INSTANCE* inst, int enabled);
 
+
+#ifdef __cplusplus
+}
+#endif
 #endif // ICMP_PROXY_H

src/proxy/socks_proxy.h

@@ -2,6 +2,11 @@
 #ifndef SOCKS_PROXY_H
 #define SOCKS_PROXY_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
 #include <stdint.h>
 #include "../lib/socket_compat.h"
 #include "../lib/ll_queue.h"
@@ -80,4 +85,8 @@ void socks_proxy_conn_free(struct socks_proxy_conn* c);
 // Освободить все соединения в списке
 void socks_proxy_conn_free_all(struct socks_proxy_conn** head, int* count);
 
+
+#ifdef __cplusplus
+}
+#endif
 #endif // SOCKS_PROXY_H

src/proxy/tcp_proxy_client.h

@@ -2,6 +2,11 @@
 #ifndef TCP_PROXY_CLIENT_H
 #define TCP_PROXY_CLIENT_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
 #include <stdint.h>
 #include <stddef.h>
 #include "../lib/socket_compat.h"
@@ -82,4 +87,8 @@ struct tcp_proxy_client* tcp_proxy_client_create(struct UTUN_INSTANCE* inst, str
 void tcp_proxy_client_destroy(struct tcp_proxy_client* p);
 void tcp_proxy_client_router_recv_cb(struct ETCP_CONN* conn, struct ll_entry* entry);
 
+
+#ifdef __cplusplus
+}
+#endif
 #endif // TCP_PROXY_CLIENT_H

src/proxy/tcp_proxy_server.h

@@ -2,6 +2,11 @@
 #ifndef TCP_PROXY_SERVER_H
 #define TCP_PROXY_SERVER_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
 #include <stdint.h>
 #include "../lib/socket_compat.h"
 #include "../lib/ll_queue.h"
@@ -73,4 +78,8 @@ void tcp_proxy_server_handle_close(struct UTUN_INSTANCE* inst, uint32_t stream_i
 void tcp_proxy_server_handle_error(struct UTUN_INSTANCE* inst, uint32_t stream_id);
 void tcp_proxy_server_handle_fin(struct UTUN_INSTANCE* inst, uint32_t stream_id);
 
+
+#ifdef __cplusplus
+}
+#endif
 #endif

src/proxy/udp_proxy.h

@@ -2,6 +2,11 @@
 #ifndef UDP_PROXY_H
 #define UDP_PROXY_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+
 #include <stdint.h>
 #include "../lib/socket_compat.h"
 
@@ -62,4 +67,8 @@ int udp_proxy_deliver_reply(struct UTUN_INSTANCE* inst,
                             uint32_t dst_ip, uint16_t dst_port,
                             const uint8_t* payload, size_t payload_len);
 
+
+#ifdef __cplusplus
+}
+#endif
 #endif // UDP_PROXY_H