sometimes you want to avoid fragmentation of the encapsulated traffic, and this
gives up the option to prevent fragmentation.
the diff includes updating etherip to show how it is used, but if
this goes through i'll update gre/egre, gif, and maybe vxlan.
# ifconfig etherip0
etherip0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
lladdr fe:e1:ba:d0:d4:dd
index 8 priority 0 llprio 3
groups: etherip
media: Ethernet autoselect
status: active
tunnel: inet 192.168.0.1 -> 192.168.1.1 nodf
if you tcpdump that traffic:
12:22:07.929427 etherip 192.168.0.1 > 192.168.1.1 ver 3 len 44: arp who-has
100.64.9.3 tell 100.64.9.1 (fe:e1:ba:d1:56:5d) [tos 0x10] [ttl 0]
# ifconfig etherip0 tunneldf
# ifconfig etherip0
etherip0: flags=8943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
lladdr fe:e1:ba:d0:d4:dd
index 8 priority 0 llprio 3
groups: etherip
media: Ethernet autoselect
status: active
tunnel: inet 192.168.0.1 -> 192.168.1.1 df
note the DF flag in tcpdump now:
12:21:11.924485 etherip 192.168.0.1 > 192.168.1.1 ver 3 len 44: arp who-has
100.64.9.2 tell 100.64.9.1 (fe:e1:ba:d1:56:5d) (DF) [tos 0x10] [ttl 0]
ok?
Index: sbin/ifconfig/ifconfig.8
===================================================================
RCS file: /cvs/src/sbin/ifconfig/ifconfig.8,v
retrieving revision 1.299
diff -u -p -r1.299 ifconfig.8
--- sbin/ifconfig/ifconfig.8 15 Feb 2018 04:21:46 -0000 1.299
+++ sbin/ifconfig/ifconfig.8 15 Feb 2018 04:22:52 -0000
@@ -1603,6 +1603,7 @@ for a complete list of the available pro
.Op Oo Fl Oc Ns Cm keepalive Ar period count
.Op Oo Fl Oc Ns Cm tunnel Ar src_address dest_address
.Op Cm tunneldomain Ar tableid
+.Op Oo Fl Oc Ns Cm tunneldf
.Op Cm tunnelttl Ar ttl
.Op Oo Fl Oc Ns Cm vnetid Ar network-id
.Ek
@@ -1654,6 +1655,10 @@ interface itself.
.Ar tableid
can be set to any valid routing table ID;
the corresponding routing domain is derived from this table.
+.It Cm tunneldf
+Do not allow fragmentation of encapsulated packets.
+.It Cm -tunneldf
+Allow fragmentation of the encapsulated packets.
.It Cm tunnelttl Ar ttl
Set the IP or multicast TTL of the tunnel packets.
If supported by the tunnel protocol,
Index: sbin/ifconfig/ifconfig.c
===================================================================
RCS file: /cvs/src/sbin/ifconfig/ifconfig.c,v
retrieving revision 1.357
diff -u -p -r1.357 ifconfig.c
--- sbin/ifconfig/ifconfig.c 10 Feb 2018 05:55:26 -0000 1.357
+++ sbin/ifconfig/ifconfig.c 15 Feb 2018 04:22:52 -0000
@@ -252,6 +252,8 @@ void setpfsync_syncpeer(const char *, in
void unsetpfsync_syncpeer(const char *, int);
void setpfsync_defer(const char *, int);
void pfsync_status(void);
+void settunneldf(const char *, int);
+void settunnelnodf(const char *, int);
void setpppoe_dev(const char *,int);
void setpppoe_svc(const char *,int);
void setpppoe_ac(const char *,int);
@@ -434,6 +436,8 @@ const struct cmd {
{ "deletetunnel", 0, 0, deletetunnel },
{ "tunneldomain", NEXTARG, 0, settunnelinst },
{ "tunnelttl", NEXTARG, 0, settunnelttl },
+ { "tunneldf", 0, 0, settunneldf },
+ { "-tunneldf", 0, 0, settunnelnodf },
{ "pppoedev", NEXTARG, 0, setpppoe_dev },
{ "pppoesvc", NEXTARG, 0, setpppoe_svc },
{ "-pppoesvc", 1, 0, setpppoe_svc },
@@ -2750,6 +2754,10 @@ phys_status(int force)
else if (ifr.ifr_ttl > 0)
printf(" ttl %d", ifr.ifr_ttl);
}
+
+ if (ioctl(s, SIOCGLIFPHYDF, (caddr_t)&ifr) == 0)
+ printf(" %s", ifr.ifr_df ? "df" : "nodf");
+
#ifndef SMALL
if (ioctl(s, SIOCGLIFPHYRTABLE, (caddr_t)&ifr) == 0 &&
(rdomainid != 0 || ifr.ifr_rdomainid != 0))
@@ -3283,6 +3291,24 @@ settunnelttl(const char *id, int param)
ifr.ifr_ttl = ttl;
if (ioctl(s, SIOCSLIFPHYTTL, (caddr_t)&ifr) < 0)
warn("SIOCSLIFPHYTTL");
+}
+
+void
+settunneldf(const char *ignored, int alsoignored)
+{
+ strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
+ ifr.ifr_df = 1;
+ if (ioctl(s, SIOCSLIFPHYDF, (caddr_t)&ifr) < 0)
+ warn("SIOCSLIFPHYDF");
+}
+
+void
+settunnelnodf(const char *ignored, int alsoignored)
+{
+ strlcpy(ifr.ifr_name, name, sizeof(ifr.ifr_name));
+ ifr.ifr_df = 0;
+ if (ioctl(s, SIOCSLIFPHYDF, (caddr_t)&ifr) < 0)
+ warn("SIOCSLIFPHYDF");
}
void
Index: sys/net/if.c
===================================================================
RCS file: /cvs/src/sys/net/if.c,v
retrieving revision 1.544
diff -u -p -r1.544 if.c
--- sys/net/if.c 10 Feb 2018 09:32:54 -0000 1.544
+++ sys/net/if.c 15 Feb 2018 04:22:52 -0000
@@ -2114,6 +2114,7 @@ ifioctl(struct socket *so, u_long cmd, c
case SIOCSLIFPHYADDR:
case SIOCSLIFPHYRTABLE:
case SIOCSLIFPHYTTL:
+ case SIOCSLIFPHYDF:
case SIOCADDMULTI:
case SIOCDELMULTI:
case SIOCSIFMEDIA:
Index: sys/net/if.h
===================================================================
RCS file: /cvs/src/sys/net/if.h,v
retrieving revision 1.191
diff -u -p -r1.191 if.h
--- sys/net/if.h 10 Feb 2018 05:52:08 -0000 1.191
+++ sys/net/if.h 15 Feb 2018 04:22:53 -0000
@@ -387,6 +387,7 @@ struct ifreq {
#define ifr_rdomainid ifr_ifru.ifru_metric /* VRF instance
(overload) */
#define ifr_vnetid ifr_ifru.ifru_vnetid /* Virtual Net Id */
#define ifr_ttl ifr_ifru.ifru_metric /* tunnel TTL
(overload) */
+#define ifr_df ifr_ifru.ifru_metric /* tunnel DF (overload) */
#define ifr_data ifr_ifru.ifru_data /* for use by interface
*/
#define ifr_index ifr_ifru.ifru_index /* interface index */
#define ifr_llprio ifr_ifru.ifru_metric /* link layer priority */
Index: sys/net/if_etherip.c
===================================================================
RCS file: /cvs/src/sys/net/if_etherip.c,v
retrieving revision 1.35
diff -u -p -r1.35 if_etherip.c
--- sys/net/if_etherip.c 12 Feb 2018 01:43:42 -0000 1.35
+++ sys/net/if_etherip.c 15 Feb 2018 04:22:53 -0000
@@ -85,6 +85,7 @@ struct etherip_softc {
struct etherip_tunnel sc_tunnel; /* must be first */
struct arpcom sc_ac;
struct ifmedia sc_media;
+ uint16_t sc_df;
uint8_t sc_ttl;
};
@@ -136,6 +137,7 @@ etherip_clone_create(struct if_clone *if
ifc->ifc_name, unit);
sc->sc_ttl = ip_defttl;
+ sc->sc_ttl = htons(0);
ifp->if_softc = sc;
ifp->if_ioctl = etherip_ioctl;
@@ -293,6 +295,14 @@ etherip_ioctl(struct ifnet *ifp, u_long
ifr->ifr_ttl = (int)sc->sc_ttl;
break;
+ case SIOCSLIFPHYDF:
+ /* commit */
+ sc->sc_df = ifr->ifr_df ? htons(IP_DF) : htons(0);
+ break;
+ case SIOCGLIFPHYDF:
+ ifr->ifr_df = sc->sc_df ? 1 : 0;
+ break;
+
case SIOCSIFMEDIA:
case SIOCGIFMEDIA:
error = ifmedia_ioctl(ifp, ifr, &sc->sc_media, cmd);
@@ -476,11 +486,12 @@ ip_etherip_output(struct ifnet *ifp, str
ip->ip_v = IPVERSION;
ip->ip_hl = sizeof(*ip) >> 2;
- ip->ip_id = htons(ip_randomid());
ip->ip_tos = IPTOS_LOWDELAY;
- ip->ip_p = IPPROTO_ETHERIP;
ip->ip_len = htons(m->m_pkthdr.len);
+ ip->ip_id = htons(ip_randomid());
+ ip->ip_off = sc->sc_df;
ip->ip_ttl = sc->sc_ttl;
+ ip->ip_p = IPPROTO_ETHERIP;
ip->ip_src = sc->sc_tunnel.t_src4;
ip->ip_dst = sc->sc_tunnel.t_dst4;
@@ -639,6 +650,9 @@ ip6_etherip_output(struct ifnet *ifp, st
eip->eip_ver = ETHERIP_VERSION;
eip->eip_res = 0;
eip->eip_pad = 0;
+
+ if (sc->sc_df)
+ SET(m->m_pkthdr.csum_flags, M_IPV6_DF_OUT);
m->m_flags &= ~(M_BCAST|M_MCAST);
m->m_pkthdr.ph_rtableid = sc->sc_tunnel.t_rtableid;
Index: sys/sys/sockio.h
===================================================================
RCS file: /cvs/src/sys/sys/sockio.h,v
retrieving revision 1.73
diff -u -p -r1.73 sockio.h
--- sys/sys/sockio.h 8 Feb 2018 13:15:32 -0000 1.73
+++ sys/sys/sockio.h 15 Feb 2018 04:22:53 -0000
@@ -191,6 +191,9 @@
#define SIOCSUMBPARAM _IOW('i', 191, struct ifreq) /* set MBIM
param */
#define SIOCGUMBPARAM _IOWR('i', 192, struct ifreq) /* get MBIM
param */
+#define SIOCSLIFPHYDF _IOW('i', 193, struct ifreq) /* set tunnel
df/nodf */
+#define SIOCGLIFPHYDF _IOWR('i', 194, struct ifreq) /* set tunnel
df/nodf */
+
#define SIOCSVH _IOWR('i', 245, struct ifreq) /* set carp
param */
#define SIOCGVH _IOWR('i', 246, struct ifreq) /* get carp
param */
