| Message ID | 20201103125242.11468-5-andrea.mayer@uniroma2.it (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next,v1,1/5] vrf: add mac header for tunneled packets when sniffer is attached | expand |
Hi Andrea,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on ipvs/master]
[also build test WARNING on linus/master v5.10-rc2 next-20201103]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]
url: https://github.com/0day-ci/linux/commits/Andrea-Mayer/seg6-add-support-for-the-SRv6-End-DT4-behavior/20201103-205553
base: https://git.kernel.org/pub/scm/linux/kernel/git/horms/ipvs.git master
config: arc-allyesconfig (attached as .config)
compiler: arceb-elf-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/0day-ci/linux/commit/266de8d69af869840a965c080862d6b5ea4a93cd
git remote add linux-review https://github.com/0day-ci/linux
git fetch --no-tags linux-review Andrea-Mayer/seg6-add-support-for-the-SRv6-End-DT4-behavior/20201103-205553
git checkout 266de8d69af869840a965c080862d6b5ea4a93cd
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arc
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
All warnings (new ones prefixed by >>):
net/ipv6/seg6_local.c:793:4: error: 'struct seg6_action_desc' has no member named 'slwt_ops'
793 | .slwt_ops = {
| ^~~~~~~~
>> net/ipv6/seg6_local.c:793:3: warning: braces around scalar initializer
793 | .slwt_ops = {
| ^
net/ipv6/seg6_local.c:793:3: note: (near initialization for 'seg6_action_table[6].static_headroom')
net/ipv6/seg6_local.c:794:6: error: field name not in record or union initializer
794 | .build_state = seg6_end_dt4_build,
| ^
net/ipv6/seg6_local.c:794:6: note: (near initialization for 'seg6_action_table[6].static_headroom')
>> net/ipv6/seg6_local.c:794:21: warning: initialization of 'int' from 'int (*)(struct seg6_local_lwt *, const void *, struct netlink_ext_ack *)' makes integer from pointer without a cast [-Wint-conversion]
794 | .build_state = seg6_end_dt4_build,
| ^~~~~~~~~~~~~~~~~~
net/ipv6/seg6_local.c:794:21: note: (near initialization for 'seg6_action_table[6].static_headroom')
vim +793 net/ipv6/seg6_local.c
757
758 static struct seg6_action_desc seg6_action_table[] = {
759 {
760 .action = SEG6_LOCAL_ACTION_END,
761 .attrs = 0,
762 .input = input_action_end,
763 },
764 {
765 .action = SEG6_LOCAL_ACTION_END_X,
766 .attrs = (1 << SEG6_LOCAL_NH6),
767 .input = input_action_end_x,
768 },
769 {
770 .action = SEG6_LOCAL_ACTION_END_T,
771 .attrs = (1 << SEG6_LOCAL_TABLE),
772 .input = input_action_end_t,
773 },
774 {
775 .action = SEG6_LOCAL_ACTION_END_DX2,
776 .attrs = (1 << SEG6_LOCAL_OIF),
777 .input = input_action_end_dx2,
778 },
779 {
780 .action = SEG6_LOCAL_ACTION_END_DX6,
781 .attrs = (1 << SEG6_LOCAL_NH6),
782 .input = input_action_end_dx6,
783 },
784 {
785 .action = SEG6_LOCAL_ACTION_END_DX4,
786 .attrs = (1 << SEG6_LOCAL_NH4),
787 .input = input_action_end_dx4,
788 },
789 {
790 .action = SEG6_LOCAL_ACTION_END_DT4,
791 .attrs = (1 << SEG6_LOCAL_TABLE),
792 .input = input_action_end_dt4,
> 793 .slwt_ops = {
> 794 .build_state = seg6_end_dt4_build,
795 },
796 },
797 {
798 .action = SEG6_LOCAL_ACTION_END_DT6,
799 .attrs = (1 << SEG6_LOCAL_TABLE),
800 .input = input_action_end_dt6,
801 },
802 {
803 .action = SEG6_LOCAL_ACTION_END_B6,
804 .attrs = (1 << SEG6_LOCAL_SRH),
805 .input = input_action_end_b6,
806 },
807 {
808 .action = SEG6_LOCAL_ACTION_END_B6_ENCAP,
809 .attrs = (1 << SEG6_LOCAL_SRH),
810 .input = input_action_end_b6_encap,
811 .static_headroom = sizeof(struct ipv6hdr),
812 },
813 {
814 .action = SEG6_LOCAL_ACTION_END_BPF,
815 .attrs = (1 << SEG6_LOCAL_BPF),
816 .input = input_action_end_bpf,
817 },
818
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Hi all, On Wed, 4 Nov 2020 04:00:10 +0800 kernel test robot <lkp@intel.com> wrote: > Hi Andrea, > > Thank you for the patch! Perhaps something to improve: > > [auto build test WARNING on ipvs/master] > [also build test WARNING on linus/master v5.10-rc2 next-20201103] > [If your patch is applied to the wrong git tree, kindly drop us a note. > And when submitting patch, we suggest to use '--base' as documented in > https://git-scm.com/docs/git-format-patch] > > url: https://github.com/0day-ci/linux/commits/Andrea-Mayer/seg6-add-support-for-the-SRv6-End-DT4-behavior/20201103-205553 > base: https://git.kernel.org/pub/scm/linux/kernel/git/horms/ipvs.git master > config: arc-allyesconfig (attached as .config) > compiler: arceb-elf-gcc (GCC) 9.3.0 > reproduce (this is a W=1 build): > wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross > chmod +x ~/bin/make.cross > # https://github.com/0day-ci/linux/commit/266de8d69af869840a965c080862d6b5ea4a93cd > git remote add linux-review https://github.com/0day-ci/linux > git fetch --no-tags linux-review Andrea-Mayer/seg6-add-support-for-the-SRv6-End-DT4-behavior/20201103-205553 > git checkout 266de8d69af869840a965c080862d6b5ea4a93cd > # save the attached .config to linux build tree > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arc > > If you fix the issue, kindly add following tag as appropriate > Reported-by: kernel test robot <lkp@intel.com> > > All warnings (new ones prefixed by >>): > > net/ipv6/seg6_local.c:793:4: error: 'struct seg6_action_desc' has no member named 'slwt_ops' > 793 | .slwt_ops = { > | ^~~~~~~~ I spent some time figuring out what happened with this patch. It seems that the patchset was not applied by the kernel test robot in the correct order. In particular, patch 3 is missing from this build attempt. I applied one patch after another in the correct order and, each time, I was able to compile the kernel (C=1 W=1) successfully with the .config file provided by the robot. Thanks, Andrea
On 11/5/20 4:57 PM, Andrea Mayer wrote: > I spent some time figuring out what happened with this patch. It seems that the > patchset was not applied by the kernel test robot in the correct order. In > particular, patch 3 is missing from this build attempt. > > I applied one patch after another in the correct order and, each time, I was > able to compile the kernel (C=1 W=1) successfully with the .config file provided > by the robot. Given that, repost the patch set. Jakub: if v2 with no changes triggers another build robot message, give Andrea time to double check whether this problem happened again before marking it in patchworks. Thanks,
diff --git a/net/ipv6/seg6_local.c b/net/ipv6/seg6_local.c index 4b0f155d641d..a41074acd43e 100644 --- a/net/ipv6/seg6_local.c +++ b/net/ipv6/seg6_local.c @@ -57,6 +57,14 @@ struct bpf_lwt_prog { char *name; }; +struct seg6_end_dt4_info { + struct net *net; + /* VRF device associated to the routing table used by the SRv6 End.DT4 + * behavior for routing IPv4 packets. + */ + int vrf_ifindex; +}; + struct seg6_local_lwt { int action; struct ipv6_sr_hdr *srh; @@ -66,6 +74,7 @@ struct seg6_local_lwt { int iif; int oif; struct bpf_lwt_prog bpf; + struct seg6_end_dt4_info dt4_info; int headroom; struct seg6_action_desc *desc; @@ -413,6 +422,194 @@ static int input_action_end_dx4(struct sk_buff *skb, return -EINVAL; } +#ifdef CONFIG_NET_L3_MASTER_DEV + +static struct net *fib6_config_get_net(const struct fib6_config *fib6_cfg) +{ + const struct nl_info *nli = &fib6_cfg->fc_nlinfo; + + return nli->nl_net; +} + +static int seg6_end_dt4_build(struct seg6_local_lwt *slwt, const void *cfg, + struct netlink_ext_ack *extack) +{ + struct seg6_end_dt4_info *info = &slwt->dt4_info; + int vrf_ifindex; + struct net *net; + + net = fib6_config_get_net(cfg); + + vrf_ifindex = l3mdev_ifindex_lookup_by_table_id(L3MDEV_TYPE_VRF, net, + slwt->table); + if (vrf_ifindex < 0) { + if (vrf_ifindex == -EPERM) { + NL_SET_ERR_MSG(extack, + "Strict mode for VRF is disabled"); + } else if (vrf_ifindex == -ENODEV) { + NL_SET_ERR_MSG(extack, "No such device"); + } else { + NL_SET_ERR_MSG(extack, "Unknown error"); + + pr_debug("seg6local: SRv6 End.DT4 creation error=%d\n", + vrf_ifindex); + } + + return vrf_ifindex; + } + + info->net = net; + info->vrf_ifindex = vrf_ifindex; + + return 0; +} + +/* The SRv6 End.DT4 behavior extracts the inner (IPv4) packet and routes the + * IPv4 packet by looking at the configured routing table. + * + * In the SRv6 End.DT4 use case, we can receive traffic (IPv6+Segment Routing + * Header packets) from several interfaces and the IPv6 destination address (DA) + * is used for retrieving the specific instance of the End.DT4 behavior that + * should process the packets. + * + * However, the inner IPv4 packet is not really bound to any receiving + * interface and thus the End.DT4 sets the VRF (associated with the + * corresponding routing table) as the *receiving* interface. + * In other words, the End.DT4 processes a packet as if it has been received + * directly by the VRF (and not by one of its slave devices, if any). + * In this way, the VRF interface is used for routing the IPv4 packet in + * according to the routing table configured by the End.DT4 instance. + * + * This design allows you to get some interesting features like: + * 1) the statistics on rx packets; + * 2) the possibility to install a packet sniffer on the receiving interface + * (the VRF one) for looking at the incoming packets; + * 3) the possibility to leverage the netfilter prerouting hook for the inner + * IPv4 packet. + * + * This function returns: + * - the sk_buff* when the VRF rcv handler has processed the packet correctly; + * - NULL when the skb is consumed by the VRF rcv handler; + * - a pointer which encodes a negative error number in case of error. + * Note that in this case, the function takes care of freeing the skb. + */ +static struct sk_buff *end_dt4_vrf_rcv(struct sk_buff *skb, + struct net_device *dev) +{ + /* based on l3mdev_ip_rcv; we are only interested in the master */ + if (unlikely(!netif_is_l3_master(dev) && !netif_has_l3_rx_handler(dev))) + goto drop; + + if (unlikely(!dev->l3mdev_ops->l3mdev_l3_rcv)) + goto drop; + + /* the decap packet (IPv4) does not come with any mac header info. + * We must unset the mac header to allow the VRF device to rebuild it, + * just in case there is a sniffer attached on the device. + */ + skb_unset_mac_header(skb); + + skb = dev->l3mdev_ops->l3mdev_l3_rcv(dev, skb, AF_INET); + if (!skb) + /* the skb buffer was consumed by the handler */ + return NULL; + + /* when a packet is received by a VRF or by one of its slaves, the + * master device reference is set into the skb. + */ + if (unlikely(skb->dev != dev || skb->skb_iif != dev->ifindex)) + goto drop; + + return skb; + +drop: + kfree_skb(skb); + return ERR_PTR(-EINVAL); +} + +static struct net_device *end_dt4_get_vrf_rcu(struct sk_buff *skb, + struct seg6_end_dt4_info *info) +{ + int vrf_ifindex = info->vrf_ifindex; + struct net *net = info->net; + + if (unlikely(vrf_ifindex < 0)) + goto error; + + if (unlikely(!net_eq(dev_net(skb->dev), net))) + goto error; + + return dev_get_by_index_rcu(net, vrf_ifindex); + +error: + return NULL; +} + +static int input_action_end_dt4(struct sk_buff *skb, + struct seg6_local_lwt *slwt) +{ + struct net_device *vrf; + struct iphdr *iph; + int err; + + if (!decap_and_validate(skb, IPPROTO_IPIP)) + goto drop; + + if (!pskb_may_pull(skb, sizeof(struct iphdr))) + goto drop; + + vrf = end_dt4_get_vrf_rcu(skb, &slwt->dt4_info); + if (unlikely(!vrf)) + goto drop; + + skb->protocol = htons(ETH_P_IP); + + skb_dst_drop(skb); + + skb_set_transport_header(skb, sizeof(struct iphdr)); + + skb = end_dt4_vrf_rcv(skb, vrf); + if (!skb) + /* packet has been processed and consumed by the VRF */ + return 0; + + if (IS_ERR(skb)) { + err = PTR_ERR(skb); + return err; + } + + iph = ip_hdr(skb); + + err = ip_route_input(skb, iph->daddr, iph->saddr, 0, skb->dev); + if (err) + goto drop; + + return dst_input(skb); + +drop: + kfree_skb(skb); + return -EINVAL; +} + +#else + +static int seg6_end_dt4_build(struct seg6_local_lwt *slwt, const void *cfg, + struct netlink_ext_ack *extack) +{ + NL_SET_ERR_MSG(extack, "Operation is not supported"); + + return -EOPNOTSUPP; +} + +static int input_action_end_dt4(struct sk_buff *skb, + struct seg6_local_lwt *slwt) +{ + kfree_skb(skb); + return -EOPNOTSUPP; +} + +#endif + static int input_action_end_dt6(struct sk_buff *skb, struct seg6_local_lwt *slwt) { @@ -601,6 +798,14 @@ static struct seg6_action_desc seg6_action_table[] = { .attrs = (1 << SEG6_LOCAL_NH4), .input = input_action_end_dx4, }, + { + .action = SEG6_LOCAL_ACTION_END_DT4, + .attrs = (1 << SEG6_LOCAL_TABLE), + .input = input_action_end_dt4, + .slwt_ops = { + .build_state = seg6_end_dt4_build, + }, + }, { .action = SEG6_LOCAL_ACTION_END_DT6, .attrs = (1 << SEG6_LOCAL_TABLE),
SRv6 End.DT4 is defined in the SRv6 Network Programming [1]. The SRv6 End.DT4 is used to implement IPv4 L3VPN use-cases in multi-tenants environments. It decapsulates the received packets and it performs IPv4 routing lookup in the routing table of the tenant. The SRv6 End.DT4 Linux implementation leverages a VRF device in order to force the routing lookup into the associated routing table. To make the End.DT4 work properly, it must be guaranteed that the routing table used for routing lookup operations is bound to one and only one VRF during the tunnel creation. Such constraint has to be enforced by enabling the VRF strict_mode sysctl parameter, i.e: $ sysctl -wq net.vrf.strict_mode=1. At JANOG44, LINE corporation presented their multi-tenant DC architecture using SRv6 [2]. In the slides, they reported that the Linux kernel is missing the support of SRv6 End.DT4 behavior. The iproute2 counterpart required for configuring the SRv6 End.DT4 behavior is already implemented along with the other supported SRv6 behaviors [3]. [1] https://tools.ietf.org/html/draft-ietf-spring-srv6-network-programming [2] https://speakerdeck.com/line_developers/line-data-center-networking-with-srv6 [3] https://patchwork.ozlabs.org/patch/799837/ Signed-off-by: Andrea Mayer <andrea.mayer@uniroma2.it> --- net/ipv6/seg6_local.c | 205 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 205 insertions(+)