QUIC: reworked migration handling. The quic connection now holds active, backup and probe paths instead of sockets. The number of migration paths is now limited and cannot be inflated by a bad client or an attacker. The client id is now associated with path rather than socket. This allows to simplify processing of output and connection ids handling. New migration abandons any previously started migrations. This allows to free consumed client ids and request new for use in future migrations and make progress in case when connection id limit is hit during migration. A path now can be revalidated without losing its state. The patch also fixes various issues with NAT rebinding case handling: - paths are now validated (previously, there was no validation and paths were left in limited state) - attempt to reuse id on different path is now again verified (this was broken in 40445fc7c403) - former path is now validated in case of apparent migration

/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#ifndef _NGX_MAIL_SMTP_MODULE_H_INCLUDED_
#define _NGX_MAIL_SMTP_MODULE_H_INCLUDED_


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


typedef struct {
    ngx_msec_t   greeting_delay;

    size_t       client_buffer_size;

    ngx_str_t    capability;
    ngx_str_t    starttls_capability;
    ngx_str_t    starttls_only_capability;

    ngx_str_t    server_name;
    ngx_str_t    greeting;

    ngx_uint_t   auth_methods;

    ngx_array_t  capabilities;
} ngx_mail_smtp_srv_conf_t;


void ngx_mail_smtp_init_session(ngx_mail_session_t *s, ngx_connection_t *c);
void ngx_mail_smtp_init_protocol(ngx_event_t *rev);
void ngx_mail_smtp_auth_state(ngx_event_t *rev);
ngx_int_t ngx_mail_smtp_parse_command(ngx_mail_session_t *s);


extern ngx_module_t  ngx_mail_smtp_module;


#endif /* _NGX_MAIL_SMTP_MODULE_H_INCLUDED_ */