Mail: connections with wrong ALPN protocols are now rejected. This is a recommended behavior by RFC 7301 and is useful for mitigation of protocol confusion attacks [1]. For POP3 and IMAP protocols IANA-assigned ALPN IDs are used [2]. For the SMTP protocol "smtp" is used. [1] https://alpaca-attack.com/ [2] https://www.iana.org/assignments/tls-extensiontype-values/

/*
 * Copyright (C) Maxim Dounin
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>


#if (NGX_HAVE_DLOPEN)

char *
ngx_dlerror(void)
{
    char  *err;

    err = (char *) dlerror();

    if (err == NULL) {
        return "";
    }

    return err;
}

#endif