Hi,

since we introduced divert-to, we converted most userland proxies and
relays to use this new interface instead of rdr-to. spamd is still
missing and should switch to divert-to as well.

divert-to has many advantages over rdr-to for proxies.  For example,
it is much easier to use (most of the attached diff is removing code),
does not depend on /dev/pf, works in-band without the asynchronous
lookup (DIOCNATLOOK ioctl), saves us from additional port allocations
by the rdr/NAT code, and even avoids potential collisions and race
conditions that could theoretically happen with the lookup.

The attached diff raises two questions:

- divert-to doesn't seem to work with spamd listening on ANY/0.0.0.0,
so you explicitly have to set the listen address.  I changed the
default to 127.0.0.1 because I don't understand why spamd should
listen on anything else by default (even our default pf.conf uses
127.0.0.1 for spamd).  But divert-to could probably be fixed to work
with ANY; I suggest to look at it independently from this diff.

- Users will have to update their PF configurations.  It is almost as
simple as changing rdr-to to divert-to in the default spamd line.  It
additionally requires to set the spamd listen address (-l) if the pf
rule is not forwarding to 127.0.0.1 (see above).

- We could keep support for both, rdr-to and divert-to, but I dislike
this approach.  This is what I did in relayd after divert-to was
introduced, but I think it is generally not a good approach to keep
compat stuff around (and relayd's rdr-to support will go away soon).

This diff might change, based on the direction we want to go, but it
does need some testing and feedback.

Reyk

Index: etc/pf.conf
===================================================================
RCS file: /cvs/src/etc/pf.conf,v
retrieving revision 1.52
diff -u -p -r1.52 pf.conf
--- etc/pf.conf 13 Feb 2013 23:11:14 -0000      1.52
+++ etc/pf.conf 19 Jun 2013 16:25:21 -0000
@@ -23,7 +23,7 @@ pass          # establish keep-state
 #table <spamd-white> persist
 #table <nospamd> persist file "/etc/mail/nospamd"
 #pass in on egress proto tcp from any to any port smtp \
-#    rdr-to 127.0.0.1 port spamd
+#    divert-to 127.0.0.1 port spamd
 #pass in on egress proto tcp from <nospamd> to any port smtp
 #pass in log on egress proto tcp from <spamd-white> to any port smtp
 #pass out log on egress proto tcp to any port smtp
Index: libexec/spamd/grey.c
===================================================================
RCS file: /cvs/src/libexec/spamd/grey.c,v
retrieving revision 1.52
diff -u -p -r1.52 grey.c
--- libexec/spamd/grey.c        2 Oct 2012 15:26:17 -0000       1.52
+++ libexec/spamd/grey.c        19 Jun 2013 16:25:21 -0000
@@ -56,10 +56,6 @@ extern int syncsend;
 /* From netinet/in.h, but only _KERNEL_ gets them. */
 #define satosin(sa)    ((struct sockaddr_in *)(sa))
 #define satosin6(sa)   ((struct sockaddr_in6 *)(sa))
-int server_lookup4(struct sockaddr_in *, struct sockaddr_in *,
-    struct sockaddr_in *);
-int server_lookup6(struct sockaddr_in6 *, struct sockaddr_in6 *,
-    struct sockaddr_in6 *);
 
 size_t whitecount, whitealloc;
 size_t trapcount, trapalloc;
@@ -135,80 +131,6 @@ configure_spamd(char **addrs, size_t cou
        fprintf(sdc, "\n");
        if (fflush(sdc) == EOF)
                syslog_r(LOG_DEBUG, &sdata, "configure_spamd: fflush failed 
(%m)");
-}
-
-
-/* Stolen from ftp-proxy */
-int
-server_lookup(struct sockaddr *client, struct sockaddr *proxy,
-    struct sockaddr *server)
-{
-       if (client->sa_family == AF_INET)
-               return (server_lookup4(satosin(client), satosin(proxy),
-                   satosin(server)));
-
-       if (client->sa_family == AF_INET6)
-               return (server_lookup6(satosin6(client), satosin6(proxy),
-                   satosin6(server)));
-
-       errno = EPROTONOSUPPORT;
-       return (-1);
-}
-
-int
-server_lookup4(struct sockaddr_in *client, struct sockaddr_in *proxy,
-    struct sockaddr_in *server)
-{
-       struct pfioc_natlook pnl;
-
-       memset(&pnl, 0, sizeof pnl);
-       pnl.direction = PF_OUT;
-       pnl.af = AF_INET;
-       pnl.proto = IPPROTO_TCP;
-       memcpy(&pnl.saddr.v4, &client->sin_addr.s_addr, sizeof pnl.saddr.v4);
-       memcpy(&pnl.daddr.v4, &proxy->sin_addr.s_addr, sizeof pnl.daddr.v4);
-       pnl.sport = client->sin_port;
-       pnl.dport = proxy->sin_port;
-
-       if (ioctl(pfdev, DIOCNATLOOK, &pnl) == -1)
-               return (-1);
-
-       memset(server, 0, sizeof(struct sockaddr_in));
-       server->sin_len = sizeof(struct sockaddr_in);
-       server->sin_family = AF_INET;
-       memcpy(&server->sin_addr.s_addr, &pnl.rdaddr.v4,
-           sizeof server->sin_addr.s_addr);
-       server->sin_port = pnl.rdport;
-
-       return (0);
-}
-
-int
-server_lookup6(struct sockaddr_in6 *client, struct sockaddr_in6 *proxy,
-    struct sockaddr_in6 *server)
-{
-       struct pfioc_natlook pnl;
-
-       memset(&pnl, 0, sizeof pnl);
-       pnl.direction = PF_OUT;
-       pnl.af = AF_INET6;
-       pnl.proto = IPPROTO_TCP;
-       memcpy(&pnl.saddr.v6, &client->sin6_addr.s6_addr, sizeof pnl.saddr.v6);
-       memcpy(&pnl.daddr.v6, &proxy->sin6_addr.s6_addr, sizeof pnl.daddr.v6);
-       pnl.sport = client->sin6_port;
-       pnl.dport = proxy->sin6_port;
-
-       if (ioctl(pfdev, DIOCNATLOOK, &pnl) == -1)
-               return (-1);
-
-       memset(server, 0, sizeof(struct sockaddr_in6));
-       server->sin6_len = sizeof(struct sockaddr_in6);
-       server->sin6_family = AF_INET6;
-       memcpy(&server->sin6_addr.s6_addr, &pnl.rdaddr.v6,
-           sizeof server->sin6_addr);
-       server->sin6_port = pnl.rdport;
-
-       return (0);
 }
 
 int
Index: libexec/spamd/sdl.c
===================================================================
RCS file: /cvs/src/libexec/spamd/sdl.c,v
retrieving revision 1.18
diff -u -p -r1.18 sdl.c
--- libexec/spamd/sdl.c 3 Nov 2007 19:16:07 -0000       1.18
+++ libexec/spamd/sdl.c 19 Jun 2013 16:25:21 -0000
@@ -23,7 +23,7 @@
  * someone is on. Spamd gets the connecting address, and looks it up
  * against all lists to determine what deferral messages to feed back
  * to the connecting machine. - The redirection to spamd will happen
- * from pf in the kernel, first macth will rdr to us. Spamd (along with
+ * from pf in the kernel, first match will divert to us. Spamd (along with
  * setup) must keep track of *all* matches, so as to tell someone all the
  * lists that they are on.
  */
Index: libexec/spamd/spamd.8
===================================================================
RCS file: /cvs/src/libexec/spamd/spamd.8,v
retrieving revision 1.119
diff -u -p -r1.119 spamd.8
--- libexec/spamd/spamd.8       27 Sep 2012 20:12:32 -0000      1.119
+++ libexec/spamd/spamd.8       19 Jun 2013 16:25:21 -0000
@@ -61,7 +61,7 @@ receiving machine.
 considers sending hosts to be of three types:
 .Pp
 .Em blacklisted
-hosts are redirected to
+hosts are diverted to
 .Nm
 and
 .Em tarpitted
@@ -78,7 +78,7 @@ such as
 .Xr sendmail 8 .
 .Pp
 .Em greylisted
-hosts are redirected to
+hosts are diverted to
 .Nm ,
 but
 .Nm
@@ -165,7 +165,7 @@ is to
 .Xr bind 2 .
 By default
 .Nm
-listens on all local addresses.
+listens on the localhost address 127.0.0.1.
 .It Fl M Ar address
 Specify a local IP address which is listed as a low priority MX record,
 used to identify and trap hosts that connect to MX hosts out of order.
@@ -177,7 +177,7 @@ The SMTP version banner that is reported
 .It Fl p Ar port
 Specify a different port number from the default port that
 .Nm
-should listen for redirected SMTP connections on.
+should listen for diverted SMTP connections on.
 The default port is found by looking for the named service
 .Dq spamd
 using
@@ -275,7 +275,7 @@ table,
 allowing connections to pass to the real MTA.
 Any addresses not found in
 .Aq spamd-white
-are redirected to
+are diverted to
 .Nm .
 .Pp
 An example
@@ -290,7 +290,7 @@ to the SMTP agent (thus bypassing
 table \*(Ltspamd-white\*(Gt persist
 table \*(Ltnospamd\*(Gt persist file "/etc/mail/nospamd"
 pass in on egress proto tcp from any to any port smtp \e
-    rdr-to 127.0.0.1 port spamd
+    divert-to 127.0.0.1 port spamd
 pass in on egress proto tcp from \*(Ltnospamd\*(Gt to any port smtp
 pass in log on egress proto tcp from \*(Ltspamd-white\*(Gt to any port smtp
 pass out log on egress proto tcp to any port smtp
@@ -469,7 +469,7 @@ However when running in blacklist-only m
 a slightly modified
 .Xr pf.conf 5
 ruleset is required,
-redirecting any addresses found in the
+diverting any addresses found in the
 .Aq spamd
 table to
 .Nm .
@@ -478,7 +478,7 @@ are passed to the real MTA.
 .Bd -literal -offset 4n
 table \*(Ltspamd\*(Gt persist
 pass in on egress proto tcp from \*(Ltspamd\*(Gt to any port smtp \e
-    rdr-to 127.0.0.1 port spamd
+    divert-to 127.0.0.1 port spamd
 .Ed
 .Pp
 Addresses can be loaded into the
Index: libexec/spamd/spamd.c
===================================================================
RCS file: /cvs/src/libexec/spamd/spamd.c,v
retrieving revision 1.112
diff -u -p -r1.112 spamd.c
--- libexec/spamd/spamd.c       19 Jun 2012 17:43:40 -0000      1.112
+++ libexec/spamd/spamd.c       19 Jun 2013 16:25:21 -0000
@@ -43,9 +43,6 @@
 #include "grey.h"
 #include "sync.h"
 
-extern int server_lookup(struct sockaddr *, struct sockaddr *,
-    struct sockaddr *);
-
 struct con {
        int fd;
        int state;
@@ -565,23 +562,19 @@ setlog(char *p, size_t len, char *f)
 }
 
 /*
- * Get address client connected to, by doing a DIOCNATLOOK call.
- * Uses server_lookup code from ftp-proxy.
+ * Get address client connected to, by doing a getsockname call.
+ * Must not be used with a NAT'ed connection (use divert-to instead of rdr-to).
  */
 void
 getcaddr(struct con *cp)
 {
-       struct sockaddr_storage spamd_end;
-       struct sockaddr *sep = (struct sockaddr *) &spamd_end;
        struct sockaddr_storage original_destination;
        struct sockaddr *odp = (struct sockaddr *) &original_destination;
        socklen_t len = sizeof(struct sockaddr_storage);
        int error;
 
        cp->caddr[0] = '\0';
-       if (getsockname(cp->fd, sep, &len) == -1)
-               return;
-       if (server_lookup((struct sockaddr *)&cp->ss, sep, odp) != 0)
+       if (getsockname(cp->fd, odp, &len) == -1)
                return;
        error = getnameinfo(odp, odp->sa_len, cp->caddr, sizeof(cp->caddr),
            NULL, 0, NI_NUMERICHOST);
@@ -1221,7 +1214,7 @@ main(int argc, char *argv[])
                if (inet_pton(AF_INET, bind_address, &sin.sin_addr) != 1)
                        err(1, "inet_pton");
        } else
-               sin.sin_addr.s_addr = htonl(INADDR_ANY);
+               sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
        sin.sin_family = AF_INET;
        sin.sin_port = htons(port);
 

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