src: Fix sending PADT to unexpected hosts when net.pppoe.term_un...

[knakahara <knakahara%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/0af1e41ff355
branches:  trunk
changeset: 318329:0af1e41ff355
user:      knakahara <knakahara%NetBSD.org@localhost>
date:      Wed Apr 18 07:40:40 2018 +0000
description:
Fix sending PADT to unexpected hosts when net.pppoe.term_unknown is enabled.

diffstat:

 sys/net/if_pppoe.c |  39 +++++++++++++++++++++++++++++++++------
 1 files changed, 33 insertions(+), 6 deletions(-)

diffs (94 lines):

diff -r 9c7245005a5b -r 0af1e41ff355 sys/net/if_pppoe.c
--- a/sys/net/if_pppoe.c        Wed Apr 18 07:38:02 2018 +0000
+++ b/sys/net/if_pppoe.c        Wed Apr 18 07:40:40 2018 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: if_pppoe.c,v 1.135 2018/04/18 07:36:26 knakahara Exp $ */
+/* $NetBSD: if_pppoe.c,v 1.136 2018/04/18 07:40:40 knakahara Exp $ */
 
 /*-
  * Copyright (c) 2002, 2008 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: if_pppoe.c,v 1.135 2018/04/18 07:36:26 knakahara Exp $");
+__KERNEL_RCSID(0, "$NetBSD: if_pppoe.c,v 1.136 2018/04/18 07:40:40 knakahara Exp $");
 
 #ifdef _KERNEL_OPT
 #include "pppoe.h"
@@ -63,6 +63,7 @@
 #include <net/if_sppp.h>
 #include <net/if_spppvar.h>
 #include <net/if_pppoe.h>
+#include <net/if_dl.h>
 
 #include <net/bpf.h>
 
@@ -236,6 +237,7 @@
 static int     pppoe_clone_destroy(struct ifnet *);
 
 static bool    pppoe_term_unknown = false;
+static int     pppoe_term_unknown_pps = 1;
 
 static struct sysctllog        *pppoe_sysctl_clog;
 static void sysctl_net_pppoe_setup(struct sysctllog **);
@@ -951,6 +953,16 @@
                m_freem(m);
 }
 
+static bool
+pppoe_is_my_frame(uint8_t *dhost, struct ifnet *rcvif)
+{
+
+       if (memcmp(CLLADDR(rcvif->if_sadl), dhost, ETHER_ADDR_LEN) == 0)
+               return true;
+
+       return false;
+}
+
 static void
 pppoe_data_input(struct mbuf *m)
 {
@@ -960,13 +972,17 @@
        struct ifnet *rcvif;
        struct psref psref;
        uint8_t shost[ETHER_ADDR_LEN];
+       uint8_t dhost[ETHER_ADDR_LEN];
        bool term_unknown = pppoe_term_unknown;
 
        KASSERT(m->m_flags & M_PKTHDR);
 
-       if (term_unknown)
+       if (term_unknown) {
                memcpy(shost, mtod(m, struct ether_header*)->ether_shost,
                    ETHER_ADDR_LEN);
+               memcpy(dhost, mtod(m, struct ether_header*)->ether_dhost,
+                   ETHER_ADDR_LEN);
+       }
        m_adj(m, sizeof(struct ether_header));
        if (m->m_pkthdr.len <= PPPOE_HEADERLEN) {
                printf("pppoe (data): dropping too short packet: %d bytes\n",
@@ -998,9 +1014,20 @@
        sc = pppoe_find_softc_by_session(session, rcvif, RW_READER);
        if (sc == NULL) {
                if (term_unknown) {
-                       printf("pppoe: input for unknown session %#x, "
-                           "sending PADT\n", session);
-                       pppoe_send_padt(rcvif, session, shost);
+                       static struct timeval lasttime = {0, 0};
+                       static int curpps = 0;
+                       /*
+                        * avoid to send wrong PADT which is response from
+                        * session stage pakcets for other hosts when parent
+                        * ethernet is promiscuous mode.
+                        */
+                       if (pppoe_is_my_frame(dhost, rcvif)
+                           && ppsratecheck(&lasttime, &curpps,
+                               pppoe_term_unknown_pps)) {
+                               printf("pppoe: input for unknown session %#x, "
+                                   "sending PADT\n", session);
+                               pppoe_send_padt(rcvif, session, shost);
+                       }
                }
                m_put_rcvif_psref(rcvif, &psref);
                goto drop;