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/*++
/* NAME
/* smtp_key 3
/* SUMMARY
/* cache/table lookup key management
/* SYNOPSIS
/* #include "smtp.h"
/*
/* char *smtp_key_prefix(buffer, delim_na, iterator, context_flags)
/* VSTRING *buffer;
/* const char *delim_na;
/* SMTP_ITERATOR *iterator;
/* int context_flags;
/* DESCRIPTION
/* The Postfix SMTP server accesses caches and lookup tables,
/* using lookup keys that contain information from various
/* contexts: per-server configuration, per-request envelope,
/* and results from DNS queries.
/*
/* These lookup keys sometimes share the same context information.
/* The primary purpose of this API is to ensure that this
/* shared context is used consistently, and that its use is
/* made explicit (both are needed to verify that there is no
/* false cache sharing).
/*
/* smtp_key_prefix() constructs a lookup key prefix from context
/* that may be shared with other lookup keys. The user is free
/* to append additional application-specific context. The result
/* value is a pointer to the result text.
/*
/* Arguments:
/* .IP buffer
/* Storage for the result.
/* .IP delim_na
/* The field delimiter character, and the optional place holder
/* character for a) information that is unavailable, b)
/* information that is inapplicable, or c) that would result
/* in an empty field. Key fields that contain "delim_na"
/* characters will be base64-encoded.
/* Do not specify "delim_na" characters that are part of the
/* base64 character set.
/* .IP iterator
/* Information that will be selected by the specified flags.
/* .IP context_flags
/* Bit-wise OR of one or more of the following.
/* .RS
/* .IP SMTP_KEY_FLAG_SERVICE
/* The global service name. This is a proxy for
/* destination-independent and request-independent context.
/* .IP SMTP_KEY_FLAG_SENDER
/* The envelope sender address. This is a proxy for sender-dependent
/* context, such as per-sender SASL authentication.
/* .IP SMTP_KEY_FLAG_REQ_NEXTHOP
/* The delivery request nexthop destination, including optional
/* [] and :port (the same form that users specify in a SASL
/* password or TLS policy lookup table). This is a proxy for
/* destination-dependent, but host-independent context.
/* .IP SMTP_KEY_FLAG_CUR_NEXTHOP
/* The current iterator's nexthop destination (delivery request
/* nexthop or fallback nexthop, including optional [] and
/* :port).
/* .IP SMTP_KEY_FLAG_HOSTNAME
/* The current iterator's remote hostname.
/* .IP SMTP_KEY_FLAG_ADDR
/* The current iterator's remote address.
/* .IP SMTP_KEY_FLAG_PORT
/* The current iterator's remote port.
/* .RE
/* DIAGNOSTICS
/* Panic: undefined flag or zero flags. Fatal: out of memory.
/* LICENSE
/* .ad
/* .fi
/* The Secure Mailer license must be distributed with this software.
/* AUTHOR(S)
/* Wietse Venema
/* IBM T.J. Watson Research
/* P.O. Box 704
/* Yorktown Heights, NY 10598, USA
/*
/* Wietse Venema
/* Google, Inc.
/* 111 8th Avenue
/* New York, NY 10011, USA
/*--*/
/*
* System library.
*/
#include <sys_defs.h>
#include <netinet/in.h> /* ntohs() for Solaris or BSD */
#include <arpa/inet.h> /* ntohs() for Linux or BSD */
#include <string.h>
/*
* Utility library.
*/
#include <msg.h>
#include <vstring.h>
#include <base64_code.h>
/*
* Global library.
*/
#include <mail_params.h>
/*
* Application-specific.
*/
#include <smtp.h>
/*
* We use a configurable field terminator and optional place holder for data
* that is unavailable or inapplicable. We base64-encode content that
* contains these characters, and content that needs obfuscation.
*/
/* smtp_key_append_na - append place-holder key field */
static void smtp_key_append_na(VSTRING *buffer, const char *delim_na)
{
if (delim_na[1] != 0)
VSTRING_ADDCH(buffer, delim_na[1]);
VSTRING_ADDCH(buffer, delim_na[0]);
}
/* smtp_key_append_str - append string-valued key field */
static void smtp_key_append_str(VSTRING *buffer, const char *str,
const char *delim_na)
{
if (str == 0 || str[0] == 0) {
smtp_key_append_na(buffer, delim_na);
} else if (str[strcspn(str, delim_na)] != 0) {
base64_encode_opt(buffer, str, strlen(str), BASE64_FLAG_APPEND);
VSTRING_ADDCH(buffer, delim_na[0]);
} else {
vstring_sprintf_append(buffer, "%s%c", str, delim_na[0]);
}
}
/* smtp_key_append_uint - append unsigned-valued key field */
static void smtp_key_append_uint(VSTRING *buffer, unsigned num,
const char *delim_na)
{
vstring_sprintf_append(buffer, "%u%c", num, delim_na[0]);
}
/* smtp_key_prefix - format common elements in lookup key */
char *smtp_key_prefix(VSTRING *buffer, const char *delim_na,
SMTP_ITERATOR *iter, int flags)
{
static const char myname[] = "smtp_key_prefix";
SMTP_STATE *state = iter->parent; /* private member */
/*
* Sanity checks.
*/
if (state == 0)
msg_panic("%s: no parent state", myname);
if (flags & ~SMTP_KEY_MASK_ALL)
msg_panic("%s: unknown key flags 0x%x",
myname, flags & ~SMTP_KEY_MASK_ALL);
if (flags == 0)
msg_panic("%s: zero flags", myname);
/*
* Initialize.
*/
VSTRING_RESET(buffer);
/*
* Per-service and per-request context.
*/
if (flags & SMTP_KEY_FLAG_SERVICE)
smtp_key_append_str(buffer, state->service, delim_na);
if (flags & SMTP_KEY_FLAG_SENDER)
smtp_key_append_str(buffer, state->request->sender, delim_na);
/*
* Per-destination context, non-canonicalized form.
*/
if (flags & SMTP_KEY_FLAG_REQ_NEXTHOP)
smtp_key_append_str(buffer, STR(iter->request_nexthop), delim_na);
if (flags & SMTP_KEY_FLAG_CUR_NEXTHOP)
smtp_key_append_str(buffer, STR(iter->dest), delim_na);
/*
* Per-host context, canonicalized form.
*/
if (flags & SMTP_KEY_FLAG_HOSTNAME)
smtp_key_append_str(buffer, STR(iter->host), delim_na);
if (flags & SMTP_KEY_FLAG_ADDR)
smtp_key_append_str(buffer, STR(iter->addr), delim_na);
if (flags & SMTP_KEY_FLAG_PORT)
smtp_key_append_uint(buffer, ntohs(iter->port), delim_na);
/*
* Requested TLS level, if applicable. TODO(tlsproxy) should the lookup
* engine also try the requested TLS level and 'stronger', in case a
* server hosts multiple domains with different TLS requirements?
*/
if (flags & SMTP_KEY_FLAG_TLS_LEVEL)
#ifdef USE_TLS
smtp_key_append_uint(buffer, state->tls->level, delim_na);
#else
smtp_key_append_na(buffer, delim_na);
#endif
VSTRING_TERMINATE(buffer);
return STR(buffer);
}
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