svn commit: r318399 - head/sys/netinet

[Andrey V. Elsukov]

Author: ae
Date: Wed May 17 09:04:09 2017
New Revision: 318399
URL: https://svnweb.freebsd.org/changeset/base/318399

Log:
  Set M_BCAST and M_MCAST flags on mbuf sent via divert socket.
  
  r290383 has changed how mbufs sent by divert socket are handled.
  Previously they are always handled by slow path processing in ip_input().
  Now ip_tryforward() is invoked from ip_input() before in_broadcast() check.
  Since diverted packet lost all mbuf flags, it passes the broadcast check
  in ip_tryforward() due to missing M_BCAST flag. In the result the broadcast
  packet is forwarded to the wire instead of be consumed by network stack.
  
  Add in_broadcast() check to the div_output() function. And restore the
  M_BCAST flag if destination address is broadcast for the given network
  interface.
  
  PR:		209491
  MFC after:	1 week

Modified:
  head/sys/netinet/ip_divert.c

Modified: head/sys/netinet/ip_divert.c
==============================================================================
--- head/sys/netinet/ip_divert.c	Wed May 17 08:38:41 2017	(r318398)
+++ head/sys/netinet/ip_divert.c	Wed May 17 09:04:09 2017	(r318399)
@@ -481,6 +481,14 @@ div_output(struct socket *so, struct mbu
 		/* Send packet to input processing via netisr */
 		switch (ip->ip_v) {
 		case IPVERSION:
+			/*
+			 * Restore M_BCAST flag when destination address is
+			 * broadcast. It is expected by ip_tryforward().
+			 */
+			if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)))
+				m->m_flags |= M_MCAST;
+			else if (in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif))
+				m->m_flags |= M_BCAST;
 			netisr_queue_src(NETISR_IP, (uintptr_t)so, m);
 			break;
 #ifdef INET6