From e5d7cd0575d61bfe4d7687018432d60976f45e2f Mon Sep 17 00:00:00 2001
From: Yves Rutschle <git1@rutschle.net>
Date: Fri, 6 Feb 2026 22:08:59 +0100
Subject: [PATCH] revert some useless changes to really fix #515

---
 proxyprotocol.c | 46 +---------------------------------------------
 1 file changed, 1 insertion(+), 45 deletions(-)

diff --git a/proxyprotocol.c b/proxyprotocol.c
index 167797a..cb5799a 100644
--- a/proxyprotocol.c
+++ b/proxyprotocol.c
@@ -89,32 +89,6 @@ static int get_info(int fd, sockpeer_t sockpeer, struct addrinfo* addr, libpp_ad
 }
 
 
-/* Turns an IPv4 address string into an IPv6 address string (i.e. prepends
- * "::fff:", in place. Assumes the buffer is big enough, but won't go over len */
-static void pp_ipv4_to_ipv6(char* addr, int len)
-{
-    char tmp[108]; /* magic number from proxy_protocol.h */
-
-    int res = snprintf(tmp, sizeof(tmp), "::ffff:%s", addr);
-    if (res >= sizeof(tmp)) {
-        print_message(msg_int_error, "Error converting IPv4 address to IPv6 address");
-        return;
-    }
-    memcpy(addr, tmp, res);
-}
-
-/* Returns the address family (ip4 or ip6) of the server-side of a connection
- * */
-static int get_serverside_family(struct connection* cnx)
-{
-    struct sockaddr addr;
-    socklen_t addrlen = sizeof(addr);
-
-    int res = getpeername(cnx->q[1].fd, &addr, &addrlen);
-    CHECK_RES_RETURN(res, "getpeername", -1);
-
-    return addr.sa_family;
-}
 
 int pp_write_header(int pp_version, struct connection* cnx)
 {
@@ -124,9 +98,6 @@ int pp_write_header(int pp_version, struct connection* cnx)
     uint16_t pp1_hdr_len;
     int32_t error;
 
-    int src_family = AF_UNSPEC;
-    int dst_family = AF_UNSPEC;
-
     struct sockaddr_storage ss;
     struct addrinfo addr;
     int res;
@@ -139,7 +110,7 @@ int pp_write_header(int pp_version, struct connection* cnx)
              &pp_info_in_v1.src_addr,
              &pp_info_in_v1.src_port);
     if (res == -1) return -1;
-    src_family = addr.ai_addr->sa_family;
+    pp_info_in_v1.address_family = family_to_pp(addr.ai_addr->sa_family);
 
     res = get_info(cnx->q[0].fd, SOCK,
              &addr,
@@ -148,21 +119,6 @@ int pp_write_header(int pp_version, struct connection* cnx)
             );
     if (res == -1) return -1;
 
-    dst_family = get_serverside_family(cnx);
-
-    pp_info_in_v1.address_family = family_to_pp(AF_INET);
-
-    /*
-     * If src IPv6/dst IPv4 or src IPv4/dst IPv6,
-     * convert IPv4 to v4-mapped IPv6 (::ffff:a.b.c.d)
-     * (refer to rfc4291, 2.2.3 for mixed-format)
-     */
-    if (src_family != dst_family) {
-        pp_ipv4_to_ipv6(pp_info_in_v1.dst_addr, sizeof(pp_info_in_v1.dst_addr));
-        pp_ipv4_to_ipv6(pp_info_in_v1.src_addr, sizeof(pp_info_in_v1.src_addr));
-        pp_info_in_v1.address_family = family_to_pp(AF_INET6);
-    }
-
     uint8_t *pp1_hdr = pp_create_hdr(pp_version, &pp_info_in_v1, &pp1_hdr_len, &error);
 
     if (!pp1_hdr) {