On Tue, Jul 10, 2018 at 4:27 PM, Yifeng Sun <pkusunyif...@gmail.com> wrote:
> Looks good to me, thanks.
>
> Reviewed-by: Yifeng Sun <pkusunyif...@gmail.com>
>
>
>
> On Tue, Jul 10, 2018 at 10:50 AM, William Tu <u9012...@gmail.com> wrote:
>>
>> Commit 9f57c67c379d ("gre: Remove support for sharing GRE protocol hook")
>> allows only single GRE packet receiver. When upstream kernel's gre module
>> is loaded, the gre.ko exclusively becomes the only gre packet receiver,
>> preventing OVS kernel module from registering another gre receiver.
>>
>> We can either try to unload the gre.ko by removing its dependencies,
>> or, in this patch, we try to register OVS as only the GRE transmit
>> portion when detecting there already exists another GRE receiver.
>>
>> Signed-off-by: William Tu <u9012...@gmail.com>
>> Cc: Greg Rose <gvrose8...@gmail.com>
>> Cc: Yifeng Sun <pkusunyif...@gmail.com>
>> ---
>> datapath/linux/compat/ip_gre.c | 60
>> +++++++++++++++++++++++++++++++++---------
>> datapath/vport.c | 12 ++++++---
>> 2 files changed, 56 insertions(+), 16 deletions(-)
>>
>> diff --git a/datapath/linux/compat/ip_gre.c
>> b/datapath/linux/compat/ip_gre.c
>> index 92de70127189..1ab798164894 100644
>> --- a/datapath/linux/compat/ip_gre.c
>> +++ b/datapath/linux/compat/ip_gre.c
>> @@ -71,6 +71,7 @@ static void erspan_build_header(struct sk_buff *skb,
>> bool truncate, bool is_ipv4);
>>
>> static struct rtnl_link_ops ipgre_link_ops __read_mostly;
>> +static bool ip_gre_loaded = false;
>>
>> #define ip_gre_calc_hlen rpl_ip_gre_calc_hlen
>> static int ip_gre_calc_hlen(__be16 o_flags)
>> @@ -1640,25 +1641,57 @@ int rpl_ipgre_init(void)
>> int err;
>>
>> err = register_pernet_device(&ipgre_tap_net_ops);
>> - if (err < 0)
>> - goto pnet_tap_failed;
>> + if (err < 0) {
>> + if (err == -EEXIST)
>> + goto ip_gre_loaded;
>> + else
>> + goto pnet_tap_failed;
>> + }
>>
>> err = register_pernet_device(&erspan_net_ops);
>> - if (err < 0)
>> - goto pnet_erspan_failed;
>> + if (err < 0) {
>> + if (err == -EEXIST)
>> + goto ip_gre_loaded;
>> + else
>> + goto pnet_erspan_failed;
>> + }
>>
>> err = register_pernet_device(&ipgre_net_ops);
>> - if (err < 0)
>> - goto pnet_ipgre_failed;
>> + if (err < 0) {
>> + if (err == -EEXIST)
>> + goto ip_gre_loaded;
>> + else
>> + goto pnet_ipgre_failed;
>> + }
>>
>> err = gre_add_protocol(&ipgre_protocol, GREPROTO_CISCO);
>> if (err < 0) {
>> pr_info("%s: can't add protocol\n", __func__);
>> - goto add_proto_failed;
>> + if (err == -EBUSY) {
>> + goto ip_gre_loaded;
>> + } else {
>> + goto add_proto_failed;
>> + }
>> }
>>
>> pr_info("GRE over IPv4 tunneling driver\n");
>> -
>> + ovs_vport_ops_register(&ovs_ipgre_vport_ops);
>> + ovs_vport_ops_register(&ovs_erspan_vport_ops);
>> + return 0;
>> +
>> +ip_gre_loaded:
>> + /* Since GRE only allows single receiver to be registerd,
>> + * we skip here so only gre transmit works, see:
>> + *
>> + * commit 9f57c67c379d88a10e8ad676426fee5ae7341b14
>> + * Author: Pravin B Shelar <pshe...@nicira.com>
>> + * Date: Fri Aug 7 23:51:52 2015 -0700
>> + * gre: Remove support for sharing GRE protocol hook
>> + *
>> + * OVS GRE receive part is disabled.
>> + */
>> + pr_info("GRE TX only over IPv4 tunneling driver\n");
>> + ip_gre_loaded = true;
>> ovs_vport_ops_register(&ovs_ipgre_vport_ops);
>> ovs_vport_ops_register(&ovs_erspan_vport_ops);
>> return 0;
>> @@ -1678,10 +1711,13 @@ void rpl_ipgre_fini(void)
>> {
>> ovs_vport_ops_unregister(&ovs_erspan_vport_ops);
>> ovs_vport_ops_unregister(&ovs_ipgre_vport_ops);
>> - gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
>> - unregister_pernet_device(&ipgre_net_ops);
>> - unregister_pernet_device(&erspan_net_ops);
>> - unregister_pernet_device(&ipgre_tap_net_ops);
>> +
>> + if (!ip_gre_loaded) {
>> + gre_del_protocol(&ipgre_protocol, GREPROTO_CISCO);
>> + unregister_pernet_device(&ipgre_net_ops);
>> + unregister_pernet_device(&erspan_net_ops);
>> + unregister_pernet_device(&ipgre_tap_net_ops);
>> + }
>> }
>>
>> #endif
>> diff --git a/datapath/vport.c b/datapath/vport.c
>> index 02f6b56d3243..05dd9dc2a149 100644
>> --- a/datapath/vport.c
>> +++ b/datapath/vport.c
>> @@ -66,11 +66,15 @@ int ovs_vport_init(void)
>> if (err)
>> goto err_lisp;
>> err = gre_init();
>> - if (err && err != -EEXIST)
>> + if (err && err != -EEXIST) {
>> goto err_gre;
>> - else if (err == -EEXIST)
>> - pr_warn("Cannot take GRE protocol entry - The ERSPAN
>> feature may not be supported\n");
>> - else {
>> + } else {
>> + if (err == -EEXIST) {
>> + pr_warn("Cannot take GRE protocol entry"\
>> + "- The ERSPAN feature may not be
>> supported\n");
thanks for the review. I found the above warning message a bit confusing.
In the case above, only the RX part of GRE/ERSPAN is not supported.
I will resubmit v2.
Regards,
William
>> + /* continue GRE tx */
>> + }
>> +
>> err = ipgre_init();
>> if (err && err != -EEXIST)
>> goto err_ipgre;
>> --
>> 2.7.4
>>
>
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