qmail-send: add QSBMF recipient capture and RFC-compliant DSN encapsulation with header-only mode

* parse and store original recipients from bounce metadata
* include Original-Recipient fields in DSN delivery-status part
* extend multipart/report formatting for RFC-compliant bounce encapsulation
* improve MIME structure and headers (Auto-Submitted, Content-Type, encoding)

1 files changed, 106 insertions, 18 deletions

diff --git a/qmail-send.c b/qmail-send.c
index 9d76228..8eed423 100644
--- a/qmail-send.c
+++ b/qmail-send.c
@@ -17,6 +17,8 @@
 #include "alloc.h"
 #include "error.h"
 #include "stralloc.h"
+#include "gen_alloc.h"
+#include "gen_allocdefs.h"
 #include "str.h"
 #include "byte.h"
 #include "fmt.h"
@@ -646,6 +648,11 @@ char *report;
    if (bouncetext.s[pos] == '\n')
      bouncetext.s[pos] = '_';
  while (!stralloc_cats(&bouncetext,">:\n")) nomem();
+ if (usebounceencap > 0) {
+   while (!stralloc_cats(&bouncetext,"XQSBMF-RECIP=")) nomem();
+   while (!stralloc_cats(&bouncetext,stripvdomprepend(recip))) nomem();
+   while (!stralloc_cats(&bouncetext,"\n")) nomem();
+ }
  while (!stralloc_cats(&bouncetext,report)) nomem();
  if (report[0])
    if (report[str_len(report) - 1] != '\n')
@@ -678,6 +685,28 @@ char *report;
  close(fd);
 }
 
+GEN_ALLOC_typedef(saa,stralloc,sa,len,a)
+GEN_ALLOC_readyplus(saa,stralloc,sa,len,a,i,n,x,10,saa_readyplus)
+static stralloc sauninit = {0};
+
+saa reciplist = {0};
+
+static int parse_qsbmf(const stralloc *line)
+{
+  if (!str_start(line->s, "XQSBMF-"))
+    return 0;
+
+  if (str_start(line->s, "XQSBMF-RECIP=")) {
+    if (!saa_readyplus(&reciplist, 1)) nomem();
+    stralloc *sa = &reciplist.sa[reciplist.len];
+    *sa = sauninit;
+    const int prefix = sizeof("XQSBMF-RECIP=") - 1;
+    if (!stralloc_copyb(sa, line->s + prefix, line->len - prefix)) nomem();
+    ++reciplist.len;
+  }
+  return 1;
+}
+
 int injectbounce(id)
 unsigned long id;
 {
@@ -739,18 +768,30 @@ unsigned long id;
    qmail_puts(&qqt,"\nTo: ");
    while (!quote2(&quoted,bouncerecip)) nomem();
    qmail_put(&qqt,quoted.s,quoted.len);
-   qmail_puts(&qqt,"\n\
-Subject: failure notice\n");
+   qmail_puts(&qqt,"\nSubject: failure notice\n");
+   qmail_puts(&qqt, "Auto-Submitted: auto-replied\n");
    if(usebounceencap > 0) {
     strid[fmt_ulong(strid,id)] = 0;
     strqp[fmt_ulong(strqp,qp)] = 0;
-    qmail_puts(&qqt,"MIME-Version: 1.0\nContent-Type: multipart/mixed; boundary=\"qrfm-");
+    qmail_puts(&qqt,"MIME-Version: 1.0\n");
+#ifdef SMTPUTF8
+    qmail_puts(&qqt,"Content-Transfer-Encoding: 8bit\n");
+#else
+    qmail_puts(&qqt,"Content-Transfer-Encoding: 7bit\n");
+#endif
+    qmail_puts(&qqt,"Content-Type: multipart/report; report-type=delivery-status;\n\tboundary=\"qrfm-");
     qmail_puts(&qqt,strid);
     qmail_puts(&qqt,strqp);
-    qmail_puts(&qqt,"\"\n\nThis is a multi-part message in MIME format.\n\n--qrfm-");
+    qmail_puts(&qqt,"\"\n\nThis is a MIME-encapsulated message.\n\n--qrfm-");
     qmail_puts(&qqt,strid);
     qmail_puts(&qqt,strqp);
-    qmail_puts(&qqt,"\nContent-Type: text/plain\n");
+    qmail_puts(&qqt,"\nContent-Description: Notification\n");
+    qmail_puts(&qqt,"Content-Type: text/plain; charset=utf-8\n");
+#ifdef SMTPUTF8
+    qmail_puts(&qqt,"Content-Transfer-Encoding: 8bit\n");
+#else
+    qmail_puts(&qqt,"Content-Transfer-Encoding: 7bit\n");
+#endif
    }
    qmail_puts(&qqt,"\n\
 Hi. This is the qmail-send program at ");
@@ -770,21 +811,62 @@ I tried to deliver a bounce message to this address, but the bounce bounced!\n\
    else
     {
      substdio_fdbuf(&ssread,read,fd,inbuf,sizeof(inbuf));
-     while ((r = substdio_get(&ssread,buf,sizeof(buf))) > 0)
-       qmail_put(&qqt,buf,r);
+     char ch;
+     static stralloc line = {0};
+     if (!saa_readyplus(&reciplist, 0)) nomem();
+     reciplist.len = 0;
+     while ((r = substdio_get(&ssread, &ch, 1)) == 1) {
+       if (!stralloc_append(&line, &ch))
+         qmail_fail(&qqt);
+       if (ch == '\n') {
+         if (!stralloc_0(&line))
+           qmail_fail(&qqt);
+         line.len--;
+         if (!parse_qsbmf(&line))
+           qmail_put(&qqt, line.s, line.len);
+         line.len = 0;
+       }
+     }
+     if (line.len > 0) {
+       if (!stralloc_0(&line))
+         qmail_fail(&qqt);
+       line.len--;
+       if (!parse_qsbmf(&line))
+         qmail_put(&qqt, line.s, line.len);
+     }
      close(fd);
      if (r == -1)
        qmail_fail(&qqt);
     }
 
    if(usebounceencap > 0) {
-    qmail_puts(&qqt,*sender.s ? "--- Attached is a copy of the message.\n\n" : "--- Attached is the original bounce.\n\n");
+    qmail_puts(&qqt,*sender.s
+      ? (bouncemaxbytes > 0 ? "--- Attached is a copy of the message.\n\n" : "--- Attached are the original headers of the message.\n\n")
+      : (bouncemaxbytes > 0 ? "--- Attached is the original bounce.\n\n" : "--- Attached are the original headers of the bounce.\n\n"));
     qmail_puts(&qqt,"--qrfm-");
     qmail_puts(&qqt,strid);
     qmail_puts(&qqt,strqp);
-    qmail_puts(&qqt,"\nContent-Type: message/rfc822\nContent-Disposition: attachment\n\n");
+    qmail_puts(&qqt,"\nContent-Description: Delivery report\n");
+    qmail_puts(&qqt,"Content-Type: message/delivery-status\n\n");
+    qmail_puts(&qqt,"Reporting-MTA: dns; ");
+    qmail_put(&qqt,bouncehost.s,bouncehost.len);
+    qmail_puts(&qqt,"\nArrival-");
+    while (!newfield_datemake(birth)) nomem();
+    qmail_put(&qqt,newfield_date.s,newfield_date.len);
+    for (int i = 0; i < reciplist.len; ++i) {
+      qmail_puts(&qqt,"\nOriginal-Recipient: rfc822; ");
+      qmail_put(&qqt, reciplist.sa[i].s, reciplist.sa[i].len);
+      qmail_puts(&qqt,"Action: failed\n");
+    }
+    qmail_puts(&qqt,"\n--qrfm-");
+    qmail_puts(&qqt,strid);
+    qmail_puts(&qqt,strqp);
+    qmail_puts(&qqt,"\nContent-Description: Undelivered Message\n");
+    qmail_puts(&qqt,"Content-Type: message/rfc822\n\n");
    } else {
-    qmail_puts(&qqt,*sender.s ? "--- Below this line is a copy of the message.\n\n" : "--- Below this line is the original bounce.\n\n");
+    qmail_puts(&qqt,*sender.s
+      ? (bouncemaxbytes > 0 ? "--- Below this line is a copy of the message.\n\n" : "--- Below this line are the original headers of the message.\n\n")
+      : (bouncemaxbytes > 0 ? "--- Below this line is the original bounce.\n\n" : "--- Below this line are the original headers of the bounce.\n\n"));
    }
 
    qmail_puts(&qqt,"Return-Path: <");
@@ -798,19 +880,25 @@ I tried to deliver a bounce message to this address, but the bounce bounced!\n\
    else
     {
      int bytestogo = bouncemaxbytes;
-     int bytestoget = (bytestogo < sizeof buf) ? bytestogo : sizeof buf;
      substdio_fdbuf(&ssread,read,fd,inbuf,sizeof(inbuf));
-     while (bytestoget > 0 && (r = substdio_get(&ssread,buf,bytestoget)) > 0) {
-       qmail_put(&qqt,buf,r);
-       bytestogo -= bytestoget;
-       bytestoget = (bytestogo < sizeof buf) ? bytestogo : sizeof buf;
-     }
-     if (r > 0) {
-       qmail_puts(&qqt,"\n\n--- End of message stripped.\n");
+     char ch, prev = 0;
+     while ((r = substdio_get(&ssread, &ch, 1)) == 1) {
+       qmail_put(&qqt, &ch, 1);
+       if (bouncemaxbytes == 0) {
+         if (prev == '\n' && ch == '\n')
+          break;
+         prev = ch;
+       }
+       else if (--bytestogo == 0)
+         break;
      }
      close(fd);
      if (r == -1)
        qmail_fail(&qqt);
+     if (bouncemaxbytes == 0)
+       qmail_puts(&qqt, "(Body supressed)\n");
+     else if (bytestogo == 0)
+       qmail_puts(&qqt, "\n\n--- End of message stripped.\n");
     }
 
    if(usebounceencap > 0) {