> On 15 Feb 2018, at 1:17 pm, Jonathan Gray <[email protected]> wrote:
>
> On Thu, Feb 15, 2018 at 01:00:53PM +1000, David Gwynne wrote:
>> the subject says it all. this also tweaks the wccp code to sneak a
>> look inside the payload to see if it is ipv4 or not. the wccp
>> protocol specifies values for the bits that overlap the ipv4 version
>> nibble that cannot be set to 4, so if it isn't 4 we can assume it is
>> the wccp header.
>>
>> in the future i would like to deprecate the sysctl.
>>
>> ok?
>
> Aren't LINK* flags something to be replaced not added?
for something as niche as this, the idea of adding a specific ioctl and
ifconfig support makes me sad.
>
> ie, gre used to use LINK0 to pick between gre/mobileip until:
>
> revision 1.80
> date: 2016/08/31 15:00:02; author: reyk; state: Exp; lines: +15 -7;
> commitid: 7HICEJ2aTYkrMgNF;
> Split gre(4) into two interfaces: gre(4) and mobileip(4).
>
> Like vlan/svlan and tun/tap, it remains a single driver that decides
> on the mode based on the interface name. This removes the need for
> removing the default link0 flag to turn gre into Mobile IP mode.
> Using linkX / IFF_LINK{0,1,2} for interface modes is a deprecated style.
>
> OK millert@ dlg@ many
>
> Not much consensus on the name but mobileip is also used for the sysctls, so
> OK henning@
>
>>
>> Index: sys/net/if_gre.c
>> ===================================================================
>> RCS file: /cvs/src/sys/net/if_gre.c,v
>> retrieving revision 1.101
>> diff -u -p -r1.101 if_gre.c
>> --- sys/net/if_gre.c 15 Feb 2018 01:03:17 -0000 1.101
>> +++ sys/net/if_gre.c 15 Feb 2018 02:55:33 -0000
>> @@ -563,8 +563,13 @@ gre_input_key(struct mbuf **mp, int *off
>> if (sc == NULL)
>> goto decline;
>>
>> + ifp = &sc->sc_if;
>> +
>> switch (gh->gre_proto) {
>> - case htons(GRE_WCCP):
>> + case htons(GRE_WCCP): {
>> + struct mbuf *n;
>> + int off;
>> +
>> /* WCCP/GRE:
>> * So far as I can see (and test) it seems that Cisco's WCCP
>> * GRE tunnel is precisely a IP-in-GRE tunnel that differs
>> @@ -574,22 +579,23 @@ gre_input_key(struct mbuf **mp, int *off
>> * the following:
>> * draft-forster-wrec-wccp-v1-00.txt
>> * draft-wilson-wrec-wccp-v2-01.txt
>> - *
>> - * So yes, we're doing a fall-through (unless, of course,
>> - * net.inet.gre.wccp is 0).
>> */
>> - switch (gre_wccp) {
>> - case 1:
>> - break;
>> - case 2:
>> - hlen += sizeof(gre_wccp);
>> - break;
>> - case 0:
>> - default:
>> +
>> + if (!gre_wccp && !ISSET(ifp->if_flags, IFF_LINK0))
>> goto decline;
>> - }
>> +
>> + /*
>> + * If the first nibble of the payload does not look like
>> + * IPv4, assume it is WCCP v2.
>> + */
>> + n = m_getptr(m, hlen, &off);
>> + if (n == NULL)
>> + goto decline;
>> + if (n->m_data[off] >> 4 != IPVERSION)
>> + hlen += sizeof(gre_wccp);
>>
>> /* FALLTHROUGH */
>> + }
>> case htons(ETHERTYPE_IP):
>> #if NBPFILTER > 0
>> bpf_af = AF_INET;
>> @@ -628,8 +634,6 @@ gre_input_key(struct mbuf **mp, int *off
>> default:
>> goto decline;
>> }
>> -
>> - ifp = &sc->sc_if;
>>
>> m_adj(m, hlen);
>>
>> Index: share/man/man4/gre.4
>> ===================================================================
>> RCS file: /cvs/src/share/man/man4/gre.4,v
>> retrieving revision 1.54
>> diff -u -p -r1.54 gre.4
>> --- share/man/man4/gre.4 15 Feb 2018 02:09:21 -0000 1.54
>> +++ share/man/man4/gre.4 15 Feb 2018 02:55:33 -0000
>> @@ -112,6 +112,10 @@ virtual network idenfitier.
>> .Nm gre
>> optionally supports sending keepalive packets to the remote endpoint,
>> which allows tunnel failure to be detected.
>> +.Nm gre
>> +interfaces can be individually configured to receive WCCP packets by
>> +setting the link-level flag
>> +.Cm link0 .
>> .Sh EXAMPLES
>> .Nm gre
>> Configuration example:
>>
