Merge remote-tracking branch 'stevee/core-90-geoip' into next

[ipfire-2.x.git] / src / patches / dnsmasq / 0060-dhcp-set-outbound-interface-via-cmsg-in-unicast-repl.patch

From 65c721200023ef0023114459a8d12f8b0a24cfd8 Mon Sep 17 00:00:00 2001
From: Lung-Pin Chang <changlp@cs.nctu.edu.tw>
Date: Thu, 19 Mar 2015 23:22:21 +0000
Subject: [PATCH 60/78] dhcp: set outbound interface via cmsg in unicast reply

  If multiple routes to the same network exist, Linux blindly picks
  the first interface (route) based on destination address, which might not be
  the one we're actually offering leases. Rather than relying on this,
  always set the interface for outgoing unicast DHCP packets.
---
 src/dhcp.c | 45 +++++++++++++++++++++++++--------------------
 1 file changed, 25 insertions(+), 20 deletions(-)

diff --git a/src/dhcp.c b/src/dhcp.c
index 5c3089ab94ff..f1f43f8d8f90 100644
--- a/src/dhcp.c
+++ b/src/dhcp.c
@@ -376,10 +376,9 @@ void dhcp_packet(time_t now, int pxe_fd)
 	}
     } 
 #if defined(HAVE_LINUX_NETWORK)
-  else if ((ntohs(mess->flags) & 0x8000) || mess->hlen == 0 ||
-	   mess->hlen > sizeof(ifr.ifr_addr.sa_data) || mess->htype == 0)
+  else
     {
-      /* broadcast to 255.255.255.255 (or mac address invalid) */
+      /* fill cmsg for outbound interface (both broadcast & unicast) */
       struct in_pktinfo *pkt;
       msg.msg_control = control_u.control;
       msg.msg_controllen = sizeof(control_u);
@@ -389,23 +388,29 @@ void dhcp_packet(time_t now, int pxe_fd)
       pkt->ipi_spec_dst.s_addr = 0;
       msg.msg_controllen = cmptr->cmsg_len = CMSG_LEN(sizeof(struct in_pktinfo));
       cmptr->cmsg_level = IPPROTO_IP;
-      cmptr->cmsg_type = IP_PKTINFO;  
-      dest.sin_addr.s_addr = INADDR_BROADCAST;
-      dest.sin_port = htons(daemon->dhcp_client_port);
-    }
-  else
-    {
-      /* unicast to unconfigured client. Inject mac address direct into ARP cache. 
-	 struct sockaddr limits size to 14 bytes. */
-      dest.sin_addr = mess->yiaddr;
-      dest.sin_port = htons(daemon->dhcp_client_port);
-      memcpy(&arp_req.arp_pa, &dest, sizeof(struct sockaddr_in));
-      arp_req.arp_ha.sa_family = mess->htype;
-      memcpy(arp_req.arp_ha.sa_data, mess->chaddr, mess->hlen);
-      /* interface name already copied in */
-      arp_req.arp_flags = ATF_COM;
-      if (ioctl(daemon->dhcpfd, SIOCSARP, &arp_req) == -1)
-	my_syslog(MS_DHCP | LOG_ERR, _("ARP-cache injection failed: %s"), strerror(errno));
+      cmptr->cmsg_type = IP_PKTINFO;
+
+      if ((ntohs(mess->flags) & 0x8000) || mess->hlen == 0 ||
+         mess->hlen > sizeof(ifr.ifr_addr.sa_data) || mess->htype == 0)
+        {
+          /* broadcast to 255.255.255.255 (or mac address invalid) */
+          dest.sin_addr.s_addr = INADDR_BROADCAST;
+          dest.sin_port = htons(daemon->dhcp_client_port);
+        }
+      else
+        {
+          /* unicast to unconfigured client. Inject mac address direct into ARP cache.
+          struct sockaddr limits size to 14 bytes. */
+          dest.sin_addr = mess->yiaddr;
+          dest.sin_port = htons(daemon->dhcp_client_port);
+          memcpy(&arp_req.arp_pa, &dest, sizeof(struct sockaddr_in));
+          arp_req.arp_ha.sa_family = mess->htype;
+          memcpy(arp_req.arp_ha.sa_data, mess->chaddr, mess->hlen);
+          /* interface name already copied in */
+          arp_req.arp_flags = ATF_COM;
+          if (ioctl(daemon->dhcpfd, SIOCSARP, &arp_req) == -1)
+            my_syslog(MS_DHCP | LOG_ERR, _("ARP-cache injection failed: %s"), strerror(errno));
+        }
     }
 #elif defined(HAVE_SOLARIS_NETWORK)
   else if ((ntohs(mess->flags) & 0x8000) || mess->hlen != ETHER_ADDR_LEN || mess->htype != ARPHRD_ETHER)
-- 
2.1.0