[master] Added -iu command line argument to dhcrelay

    Merges in 41547a

2 files changed, 53 insertions, 3 deletions

diff --git a/relay/dhcrelay.8 b/relay/dhcrelay.8
index 67065663..1091edb7 100644
--- a/relay/dhcrelay.8
+++ b/relay/dhcrelay.8
@@ -77,6 +77,14 @@ dhcrelay - Dynamic Host Configuration Protocol Relay Agent
 .B -i
 .I interfaceN 
 ]
+[
+.B -iu
+.I interface0
+[
+.B ...
+.B -iu
+.I interfaceN
+]
 .B -l
 .I interface
 ]
@@ -204,12 +212,19 @@ a query that came via a different relay agent.  If this option is not
 specified, such packets will be relayed anyway.
 .TP
 -i \fIifname\fR
-Listen for DHCPv4/BOOTP queries on interface \fIifname\fR.  Multiple
+Listen for DHCPv4/BOOTP traffic on interface \fIifname\fR.  Multiple
 interfaces may be specified by using more than one \fB-i\fR option.  If
 no interfaces are specified on the command line, dhcrelay will identify
 all network interfaces, eliminating non-broadcast interfaces if possible,
 and attempt to listen on all of them.
 .TP
+-iu \fIifname\fR
+Specifies an upstream network interface for DHCPv4 relay mode: an
+interface from which replies from servers and other relay agents will be
+accepted.  Multiple interfaces may be specified by using more
+than one \fB-u\fR option.  This argument is intended to be used
+in conjunction with one or more -i arguments.
+.TP
 -m \fIappend\fR|\fIreplace\fR|\fIforward\fR|\fIdiscard\fR
 Control the handling of incoming DHCPv4 packets which already contain
 relay agent options.  If such a packet does not have \fIgiaddr\fR set in
diff --git a/relay/dhcrelay.c b/relay/dhcrelay.c
index c72d6f31..4127fccc 100644
--- a/relay/dhcrelay.c
+++ b/relay/dhcrelay.c
@@ -153,6 +153,7 @@ char *progname;
 "                     [-pf <pid-file>] [--no-pid]\n"\
 "                     [-m append|replace|forward|discard]\n" \
 "                     [-i interface0 [ ... -i interfaceN]\n" \
+"                     [-iu interface0 [ ... -iu interfaceN]\n" \
 "                     [-U interface]\n" \
 "                     server0 [ ... serverN]\n\n" \
 "       %s -6   [-d] [-q] [-I] [-c <hops>] [-p <port>]\n" \
@@ -168,6 +169,7 @@ char *progname;
 "                [-pf <pid-file>] [--no-pid]\n" \
 "                [-m append|replace|forward|discard]\n" \
 "                [-i interface0 [ ... -i interfaceN]\n" \
+"                [-iu interface0 [ ... -iu interfaceN]\n" \
 "                [-U interface]\n" \
 "                server0 [ ... serverN]\n\n"
 #endif
@@ -325,7 +327,34 @@ main(int argc, char **argv) {
 					  isc_result_totext(status));
 			}
 			strcpy(tmp->name, argv[i]);
-			interface_snorf(tmp, INTERFACE_REQUESTED);
+			interface_snorf(tmp, (INTERFACE_REQUESTED |
+					     INTERFACE_STREAMS));
+			interface_dereference(&tmp, MDL);
+		} else if (!strcmp(argv[i], "-iu")) {
+#ifdef DHCPv6
+			if (local_family_set && (local_family == AF_INET6)) {
+				usage(use_v4command, argv[i]);
+			}
+			local_family_set = 1;
+			local_family = AF_INET;
+#endif
+			if (++i == argc) {
+				usage(use_noarg, argv[i-1]);
+			}
+			if (strlen(argv[i]) >= sizeof(tmp->name)) {
+				log_fatal("%s: interface name too long "
+					  "(is %ld)",
+					  argv[i], (long)strlen(argv[i]));
+			}
+			status = interface_allocate(&tmp, MDL);
+			if (status != ISC_R_SUCCESS) {
+				log_fatal("%s: interface_allocate: %s",
+					  argv[i],
+					  isc_result_totext(status));
+			}
+			strcpy(tmp->name, argv[i]);
+			interface_snorf(tmp, (INTERFACE_REQUESTED |
+					     INTERFACE_UPSTREAM));
 			interface_dereference(&tmp, MDL);
 		} else if (!strcmp(argv[i], "-a")) {
 #ifdef DHCPv6
@@ -398,7 +427,8 @@ main(int argc, char **argv) {
 			uplink->name[sizeof(uplink->name) - 1] = 0x00;
 			strncpy(uplink->name, argv[i],
 				sizeof(uplink->name) - 1);
-			interface_snorf(uplink, INTERFACE_REQUESTED);
+			interface_snorf(uplink, (INTERFACE_REQUESTED |
+						INTERFACE_STREAMS));
 
 			/* Turn on -a, in case they don't do so explicitly */
 			add_agent_options = 1;
@@ -730,6 +760,11 @@ do_relay4(struct interface_info *ip, struct dhcp_packet *packet,
 
 	/* If it's a bootreply, forward it to the client. */
 	if (packet->op == BOOTREPLY) {
+		if (!(ip->flags & INTERFACE_UPSTREAM)) {
+			log_debug("Dropping reply received on %s", ip->name);
+			return;
+		}
+
 		if (!(packet->flags & htons(BOOTP_BROADCAST)) &&
 			can_unicast_without_arp(out)) {
 			to.sin_addr = packet->yiaddr;