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Add the "Monitor" interface flag.

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Setting this flag on an ethernet interface blocks transmission of packets
and discards incoming packets after BPF processing.

This is useful if you want to monitor network trafic but not interact
with the network in question.

Sponsored by:	http://www.babeltech.dk
This commit is contained in:
Poul-Henning Kamp 2002-09-27 18:57:47 +00:00
parent ca916247cd
commit afbe3a0f81
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=104044
4 changed files with 21 additions and 0 deletions
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11
sbin/ifconfig/ifconfig.8
View File

@ -504,6 +504,17 @@ for more information.
.It Fl link Op Cm 0 No - Cm 2
.Sm on
Disable special processing at the link level with the specified interface.
.It Cm monitor
.Sm on
Put the interface in monitor mode.
No packets are transmitted and received packets are discarded after
.Xr bpf 4
processing.
.Sm off
.It Fl monitor
.Sm on
Take the interface out of monitor mode.
.Sm off
.It Cm up
Mark an interface
.Dq up .

2
sbin/ifconfig/ifconfig.c
View File

@ -241,6 +241,8 @@ struct cmd {
{ "-link1", -IFF_LINK1, setifflags },
{ "link2", IFF_LINK2, setifflags },
{ "-link2", -IFF_LINK2, setifflags },
{ "monitor", IFF_MONITOR, setifflags },
{ "-monitor", -IFF_MONITOR, setifflags },
#ifdef USE_IF_MEDIA
{ "media", NEXTARG, setmedia },
{ "mediaopt", NEXTARG, setmediaopt },

1
sys/net/if.h
View File

@ -141,6 +141,7 @@ struct if_data {
#define IFF_MULTICAST 0x8000 /* supports multicast */
#define IFF_POLLING 0x10000 /* Interface is in polling mode. */
#define IFF_PPROMISC 0x20000 /* user-requested promisc mode */
#define IFF_MONITOR 0x40000 /* user-requested monitor mode */
/* flags set internally only: */
#define IFF_CANTCHANGE \

7
sys/net/if_ethersubr.c
View File

@ -162,6 +162,8 @@ ether_output(ifp, m, dst, rt0)
senderr(error);
#endif
if (ifp->if_flags & IFF_MONITOR)
senderr(ENETDOWN);
if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING))
senderr(ENETDOWN);
rt = rt0;
@ -583,6 +585,11 @@ ether_input(struct ifnet *ifp, struct ether_header *eh, struct mbuf *m)
bpf_mtap(ifp, (struct mbuf *)&mh);
}
if (ifp->if_flags & IFF_MONITOR) {
m_freem(m);
return;
}
#ifdef MAC
mac_create_mbuf_from_ifnet(ifp, m);
#endif