bounce_workaround.c revision 1.1 
1/*	$NetBSD: bounce_workaround.c,v 1.1 2010/06/17 18:06:53 tron Exp $	*/
2
3/*++
4/* NAME
5/*	bounce_workaround 3
6/* SUMMARY
7/*	Send non-delivery notification with sender override
8/* SYNOPSIS
9/*	#include "local.h"
10/*
11/*	int	bounce_workaround(state)
12/*	LOCAL_STATE state;
13/* DESCRIPTION
14/*	This module works around a limitation in the bounce daemon
15/*	protocol, namely, the assumption that the envelope sender
16/*	address in a queue file is the delivery status notification
17/*	address for all recipients in that queue file. The assumption
18/*	is not valid when the local(8) delivery agent overrides the
19/*	envelope sender address by an owner- alias, for one or more
20/*	recipients in the queue file.
21/*
22/*	Sender address override is a problem only when delivering
23/*	to command or file, or when breaking a Delivered-To loop.
24/*	The local(8) delivery agent saves normal recipients to a
25/*	new queue file, together with the replacement envelope
26/*	sender address; delivery then proceeds from that new queue
27/*	file, and no workaround is needed.
28/*
29/*	The workaround sends one non-delivery notification for each
30/*	failed delivery that has a replacement sender address.  The
31/*	notifications are not aggregated, unlike notifications to
32/*	non-replaced sender addresses. In practice, a local alias
33/*	rarely has more than one file or command destination (if
34/*	only because soft error handling is problematic).
35/*
36/*	Arguments:
37/* .IP state
38/*	The attributes that specify the message, recipient and more.
39/*	Attributes describing alias, include or forward expansion.
40/*	A table with the results from expanding aliases or lists.
41/*	A table with delivered-to: addresses taken from the message.
42/* DIAGNOSTICS
43/*	Fatal errors: out of memory. The result is non-zero when
44/*	the operation should be tried again. Warnings: malformed
45/*	address.
46/* BUGS
47/*	The proper fix is to record in the bounce logfile an error
48/*	return address for each individual recipient. This would
49/*	eliminate the need for VERP-specific bounce protocol code,
50/*	and would move complexity from the bounce client side to
51/*	the bounce server side where it more likely belongs.
52/* LICENSE
53/* .ad
54/* .fi
55/*	The Secure Mailer license must be distributed with this
56/*	software.
57/* AUTHOR(S)
58/*	Wietse Venema
59/*	IBM T.J. Watson Research
60/*	P.O. Box 704
61/*	Yorktown Heights, NY 10598, USA
62/*--*/
63
64/* System library. */
65
66#include <sys_defs.h>
67#include <strings.h>
68
69/* Utility library. */
70
71#include <msg.h>
72#include <mymalloc.h>
73#include <vstring.h>
74#include <split_at.h>
75
76/* Global library. */
77
78#include <mail_params.h>
79#include <strip_addr.h>
80#include <stringops.h>
81#include <bounce.h>
82#include <split_addr.h>
83#include <canon_addr.h>
84
85/* Application-specific. */
86
87#include "local.h"
88
89int     bounce_workaround(LOCAL_STATE state)
90{
91    const char *myname = "bounce_workaround";
92    VSTRING *canon_owner = 0;
93    int     rcpt_stat;
94
95    /*
96     * Look up the substitute sender address.
97     */
98    if (var_ownreq_special) {
99	char   *stripped_recipient;
100	char   *owner_alias;
101	const char *owner_expansion;
102
103#define FIND_OWNER(lhs, rhs, addr) { \
104	lhs = concatenate("owner-", addr, (char *) 0); \
105	(void) split_at_right(lhs, '@'); \
106	rhs = maps_find(alias_maps, lhs, DICT_FLAG_NONE); \
107    }
108
109	FIND_OWNER(owner_alias, owner_expansion, state.msg_attr.rcpt.address);
110	if (owner_expansion == 0
111	    && (stripped_recipient = strip_addr(state.msg_attr.rcpt.address,
112						(char **) 0,
113						*var_rcpt_delim)) != 0) {
114	    myfree(owner_alias);
115	    FIND_OWNER(owner_alias, owner_expansion, stripped_recipient);
116	    myfree(stripped_recipient);
117	}
118	if (owner_expansion != 0) {
119	    canon_owner = canon_addr_internal(vstring_alloc(10),
120					      var_exp_own_alias ?
121					      owner_expansion : owner_alias);
122	    SET_OWNER_ATTR(state.msg_attr, STR(canon_owner), state.level);
123	}
124	myfree(owner_alias);
125    }
126
127    /*
128     * Send a delivery status notification with a single recipient to the
129     * substitute sender address, before completion of the delivery request.
130     */
131    if (canon_owner) {
132	rcpt_stat = bounce_one(BOUNCE_FLAGS(state.request),
133			       BOUNCE_ONE_ATTR(state.msg_attr));
134	vstring_free(canon_owner);
135    }
136
137    /*
138     * Send a regular delivery status notification, after completion of the
139     * delivery request.
140     */
141    else {
142	rcpt_stat = bounce_append(BOUNCE_FLAGS(state.request),
143				  BOUNCE_ATTR(state.msg_attr));
144    }
145    return (rcpt_stat);
146}
147