Thanks to John Cummings.

1 files changed, 333 insertions, 0 deletions

diff --git a/src/cmd/upas/smtp/mxdial.c b/src/cmd/upas/smtp/mxdial.c
new file mode 100644
index 00000000..aea5f256
--- /dev/null
+++ b/src/cmd/upas/smtp/mxdial.c
@@ -0,0 +1,333 @@
+#include "common.h"
+#include <ndb.h>
+#include "smtp.h"	/* to publish dial_string_parse */
+
+enum
+{
+	Nmx=	16,
+	Maxstring=	256,
+};
+
+typedef struct Mx	Mx;
+struct Mx
+{
+	char host[256];
+	char ip[24];
+	int pref;
+};
+static Mx mx[Nmx];
+
+Ndb *db;
+extern int debug;
+
+static int	mxlookup(DS*, char*);
+static int	mxlookup1(DS*, char*);
+static int	compar(void*, void*);
+static int	callmx(DS*, char*, char*);
+static void expand_meta(DS *ds);
+extern int	cistrcmp(char*, char*);
+
+int
+mxdial(char *addr, char *ddomain, char *gdomain)
+{
+	int fd;
+	DS ds;
+	char err[Errlen];
+
+	addr = netmkaddr(addr, 0, "smtp");
+	dial_string_parse(addr, &ds);
+
+	/* try connecting to destination or any of it's mail routers */
+	fd = callmx(&ds, addr, ddomain);
+
+	/* try our mail gateway */
+	rerrstr(err, sizeof(err));
+	if(fd < 0 && gdomain && strstr(err, "can't translate") != 0) {
+		fprint(2,"dialing %s\n",gdomain);
+		fd = dial(netmkaddr(gdomain, 0, "smtp"), 0, 0, 0);
+	}
+
+	return fd;
+}
+
+/*
+ *  take an address and return all the mx entries for it,
+ *  most preferred first
+ */
+static int
+callmx(DS *ds, char *dest, char *domain)
+{
+	int fd, i, nmx;
+	char addr[Maxstring];
+
+	/* get a list of mx entries */
+	nmx = mxlookup(ds, domain);
+	if(nmx < 0){
+		/* dns isn't working, don't just dial */
+		return -1;
+	}
+	if(nmx == 0){
+		if(debug)
+			fprint(2, "mxlookup returns nothing\n");
+		return dial(dest, 0, 0, 0);
+	}
+
+	/* refuse to honor loopback addresses given by dns */
+	for(i = 0; i < nmx; i++){
+		if(strcmp(mx[i].ip, "127.0.0.1") == 0){
+			if(debug)
+				fprint(2, "mxlookup returns loopback\n");
+			werrstr("illegal: domain lists 127.0.0.1 as mail server");
+			return -1;
+		}
+	}
+
+	/* sort by preference */
+	if(nmx > 1)
+		qsort(mx, nmx, sizeof(Mx), compar);
+
+	/* dial each one in turn */
+	for(i = 0; i < nmx; i++){
+		snprint(addr, sizeof(addr), "%s/%s!%s!%s", ds->netdir, ds->proto,
+			mx[i].host, ds->service);
+		if(debug)
+			fprint(2, "mxdial trying %s\n", addr);
+		fd = dial(addr, 0, 0, 0);
+		if(fd >= 0)
+			return fd;
+	}
+	return -1;
+}
+
+/*
+ *  call the dns process and have it try to resolve the mx request
+ *
+ *  this routine knows about the firewall and tries inside and outside
+ *  dns's seperately.
+ */
+static int
+mxlookup(DS *ds, char *domain)
+{
+	int n;
+
+	/* just in case we find no domain name */
+	strcpy(domain, ds->host);
+
+	if(ds->netdir){
+		n = mxlookup1(ds, domain);
+	} else {
+		ds->netdir = "/net";
+		n = mxlookup1(ds, domain);
+		if(n == 0) {
+			ds->netdir = "/net.alt";
+			n = mxlookup1(ds, domain);
+		}
+	}
+
+	return n;
+}
+
+static int
+mxlookup1(DS *ds, char *domain)
+{
+	char buf[1024];
+	char dnsname[Maxstring];
+	char *fields[4];
+	int i, n, fd, nmx;
+
+	snprint(dnsname, sizeof dnsname, "%s/dns", ds->netdir);
+
+	fd = open(dnsname, ORDWR);
+	if(fd < 0)
+		return 0;
+
+	nmx = 0;
+	snprint(buf, sizeof(buf), "%s mx", ds->host);
+	if(debug)
+		fprint(2, "sending %s '%s'\n", dnsname, buf);
+	n = write(fd, buf, strlen(buf));
+	if(n < 0){
+		rerrstr(buf, sizeof buf);
+		if(debug)
+			fprint(2, "dns: %s\n", buf);
+		if(strstr(buf, "dns failure")){
+			/* if dns fails for the mx lookup, we have to stop */
+			close(fd);
+			return -1;
+		}
+	} else {
+		/*
+		 *  get any mx entries
+		 */
+		seek(fd, 0, 0);
+		while(nmx < Nmx && (n = read(fd, buf, sizeof(buf)-1)) > 0){
+			buf[n] = 0;
+			if(debug)
+				fprint(2, "dns mx: %s\n", buf);
+			n = getfields(buf, fields, 4, 1, " \t");
+			if(n < 4)
+				continue;
+
+			if(strchr(domain, '.') == 0)
+				strcpy(domain, fields[0]);
+
+			strncpy(mx[nmx].host, fields[3], sizeof(mx[n].host)-1);
+			mx[nmx].pref = atoi(fields[2]);
+			nmx++;
+		}
+		if(debug)
+			fprint(2, "dns mx; got %d entries\n", nmx);
+	}
+
+	/*
+	 * no mx record? try name itself.
+	 */
+	/*
+	 * BUG? If domain has no dots, then we used to look up ds->host
+	 * but return domain instead of ds->host in the list.  Now we return
+	 * ds->host.  What will this break?
+	 */
+	if(nmx == 0){
+		mx[0].pref = 1;
+		strncpy(mx[0].host, ds->host, sizeof(mx[0].host));
+		nmx++;
+	}
+
+	/*
+	 * look up all ip addresses
+	 */
+	for(i = 0; i < nmx; i++){
+		seek(fd, 0, 0);
+		snprint(buf, sizeof buf, "%s ip", mx[i].host);
+		mx[i].ip[0] = 0;
+		if(write(fd, buf, strlen(buf)) < 0)
+			goto no;
+		seek(fd, 0, 0);
+		if((n = read(fd, buf, sizeof buf-1)) < 0)
+			goto no;
+		buf[n] = 0;
+		if(getfields(buf, fields, 4, 1, " \t") < 3)
+			goto no;
+		strncpy(mx[i].ip, fields[2], sizeof(mx[i].ip)-1);
+		continue;
+
+	no:
+		/* remove mx[i] and go around again */
+		nmx--;
+		mx[i] = mx[nmx];
+		i--;
+	}
+	return nmx;		
+}
+
+static int
+compar(void *a, void *b)
+{
+	return ((Mx*)a)->pref - ((Mx*)b)->pref;
+}
+
+/* break up an address to its component parts */
+void
+dial_string_parse(char *str, DS *ds)
+{
+	char *p, *p2;
+
+	strncpy(ds->buf, str, sizeof(ds->buf));
+	ds->buf[sizeof(ds->buf)-1] = 0;
+
+	p = strchr(ds->buf, '!');
+	if(p == 0) {
+		ds->netdir = 0;
+		ds->proto = "net";
+		ds->host = ds->buf;
+	} else {
+		if(*ds->buf != '/'){
+			ds->netdir = 0;
+			ds->proto = ds->buf;
+		} else {
+			for(p2 = p; *p2 != '/'; p2--)
+				;
+			*p2++ = 0;
+			ds->netdir = ds->buf;
+			ds->proto = p2;
+		}
+		*p = 0;
+		ds->host = p + 1;
+	}
+	ds->service = strchr(ds->host, '!');
+	if(ds->service)
+		*ds->service++ = 0;
+	if(*ds->host == '$')
+		expand_meta(ds);
+}
+
+#if 0 /* jpc */
+static void
+expand_meta(DS *ds)
+{
+	char buf[128], cs[128], *net, *p;
+	int fd, n;
+
+	net = ds->netdir;
+	if(!net)
+		net = "/net";
+
+	if(debug)
+		fprint(2, "expanding %s!%s\n", net, ds->host);
+	snprint(cs, sizeof(cs), "%s/cs", net);
+	if((fd = open(cs, ORDWR)) == -1){
+		if(debug)
+			fprint(2, "open %s: %r\n", cs);
+		syslog(0, "smtp", "cannot open %s: %r", cs);
+		return;
+	}
+
+	snprint(buf, sizeof(buf), "!ipinfo %s", ds->host+1);	// +1 to skip $
+	if(write(fd, buf, strlen(buf)) <= 0){
+		if(debug)
+			fprint(2, "write %s: %r\n", cs);
+		syslog(0, "smtp", "%s to %s - write failed: %r", buf, cs);
+		close(fd);
+		return;
+	}
+
+	seek(fd, 0, 0);
+	if((n = read(fd, ds->expand, sizeof(ds->expand)-1)) < 0){
+		if(debug)
+			fprint(2, "read %s: %r\n", cs);
+		syslog(0, "smtp", "%s - read failed: %r", cs);
+		close(fd);
+		return;
+	}
+	close(fd);
+
+	ds->expand[n] = 0;
+	if((p = strchr(ds->expand, '=')) == nil){
+		if(debug)
+			fprint(2, "response %s: %s\n", cs, ds->expand);
+		syslog(0, "smtp", "%q from %s - bad response: %r", ds->expand, cs);
+		return;
+	}
+	ds->host = p+1;
+
+	/* take only first one returned (quasi-bug) */
+	if((p = strchr(ds->host, ' ')) != nil)
+		*p = 0;
+}
+#endif /* jpc */
+
+static void
+expand_meta(DS *ds)
+{
+	Ndb *db;
+	Ndbs s;
+	char *sys, *smtpserver;
+
+	sys = sysname();
+	db = ndbopen(unsharp("#9/ndb/local"));
+	fprint(2,"%s",ds->host);
+	smtpserver = ndbgetvalue(db, &s, "sys", sys, "smtp", nil);
+	snprint(ds->host,128,"%s",smtpserver);
+	fprint(2," exanded to %s\n",ds->host);
+
+}