diff --git a/src/socks5.c b/src/socks5.c
index 6bb1e7f..a129cd4 100644
--- a/src/socks5.c
+++ b/src/socks5.c
@@ -132,7 +132,7 @@ int on_socks5_send_client_req(struct evt_core_ctx* ctx, struct evt_core_fdinfo*
 
 int socks5_server_reply_atyp_ipv4(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
   struct socks5_ctx* s5ctx = fdinfo->other;
-  size_t fixed_headers_size = (void*)&s5ctx->sr.bind_addr.ipv4 - (void*)&s5ctx->sr;
+  size_t fixed_headers_size = (char*)&s5ctx->sr.bind_addr.ipv4 - (char*)&s5ctx->sr;
   size_t host_size = sizeof(s5ctx->sr.bind_addr.ipv4);
   uint64_t relative_cursor = (s5ctx->sr_cursor - fixed_headers_size);
   int nread = 0;
@@ -157,7 +157,7 @@ int socks5_server_reply_atyp_ipv4(struct evt_core_ctx* ctx, struct evt_core_fdin
 
 int socks5_server_reply_atyp_ipv6(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
   struct socks5_ctx* s5ctx = fdinfo->other;
-  size_t fixed_headers_size = (void*)&s5ctx->sr.bind_addr.ipv6 - (void*)&s5ctx->sr;
+  size_t fixed_headers_size = (char*)&s5ctx->sr.bind_addr.ipv6 - (char*)&s5ctx->sr;
   size_t host_size = sizeof(s5ctx->sr.bind_addr.ipv6);
   uint64_t relative_cursor = (s5ctx->sr_cursor - fixed_headers_size);
   int nread = 0;
@@ -181,7 +181,7 @@ int socks5_server_reply_atyp_ipv6(struct evt_core_ctx* ctx, struct evt_core_fdin
 
 int socks5_server_reply_atyp_dn(struct evt_core_ctx* ctx, struct evt_core_fdinfo* fdinfo) {
   struct socks5_ctx* s5ctx = fdinfo->other;
-  size_t fixed_headers_size = (void*)&s5ctx->sr.bind_addr.ipv6 - (void*)&s5ctx->sr;
+  size_t fixed_headers_size = (char*)&s5ctx->sr.bind_addr.ipv6 - (char*)&s5ctx->sr;
   size_t dn_size_size = sizeof(s5ctx->sr.bind_addr.dns.len);
   uint64_t relative_cursor = 0;
   int nread = 0;
@@ -215,7 +215,7 @@ int socks5_server_reply_atyp_dn(struct evt_core_ctx* ctx, struct evt_core_fdinfo
 }
 
 size_t socks5_server_reply_size(struct server_reply* sr) {
-  size_t fixed_headers_size = (char*)&sr->bind_addr - (char*)&sr;
+  size_t fixed_headers_size = (char*)&sr->bind_addr - (char*)sr;
   size_t fixed_tail_size = (char*)(sr + 1) - (char*)&sr->port;
   size_t host_size = 0;