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SubjectRe: [RESEND PATCH v5] net: bonding: Add support for IPV6 ns/na to balance-alb/balance-tlb mode
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在 2022/1/11 3:23, Jay Vosburgh 写道:
> I'm getting back to this after the holiday break, and have some
> follow up from our prior discussions that I'll paste in below.
>
> Sun Shouxin <sunshouxin@chinatelecom.cn> wrote:
>
>> Since ipv6 neighbor solicitation and advertisement messages
>> isn't handled gracefully in bonding6 driver, we can see packet
>> drop due to inconsistency bewteen mac address in the option
>> message and source MAC .
>>
>> Another examples is ipv6 neighbor solicitation and advertisement
>> messages from VM via tap attached to host brighe, the src mac
>> mighe be changed through balance-alb mode, but it is not synced
>> with Link-layer address in the option message.
>>
>> The patch implements bond6's tx handle for ipv6 neighbor
>> solicitation and advertisement messages.
>>> I'm not sure what you've changed here for v5 as there's no
>>> changelog, but I believe the observed problems to be a transmit side
>>> effect (i.e., it is induced by the balance-tlb mode balancing of
>>> outgoing traffic). As such, the tlb side will rebalance all of the
>>> traffic every ten seconds, so any MAC ND_OPT_*_LL_ADDR option
>>> assignments in the outgoing NS/NA datagrams will only be valid for that
>>> length of time, correct?
>> Yes,  MAC ND_OPT_*_LL_ADDR option assignments in the outgoing NS/NA
>> datagrams will only be valid for that length of time ,and then,
>> it will be inconsistensy in the next ten seconds.
> So, presumably then the original issue (with the topology
> diagram that's now omitted) can recur 10 seconds later (after a TLB
> rebalance)? If so, I don't understand why this patch is an improvement.
>
>>> In any event, my real question is whether simply disabling tlb
>>> balancing for NS/NA datagrams will resolve the observed issues (i.e.,
>>> have bond_xmit_tlb_slave_get return NULL for IPv6 NS/NA datagrams).
>>> Doing so will cause all NS/NA traffic to egress through the active
>>> interface. There's already a test in your logic to check for the
>>> tx_slave != bond->curr_active_slave, so presumably everything works
>>> correctly if the NS/NA goes out on the curr_active_slave. If the "edit
>>> NS/NA datagrams" solution works even in the face of rebalance of
>>> traffic, then would simply assigning all NS/NA traffic to the
>>> curr_active_slave eliminate the problem?
>> Yes, assigning all Ns/Na traffic to the curr_active_slave can resolve the
>> difference between mac in the Ns/Na options with the source mac.
>> But this makes the rlb doesn't work in the alb mode,
>> one interface with bond6 will not receive any ingress packets.
>> It is mismatch Bond6 specification.
> Does assigning all NS/NA to the curr_active_slave avoid the
> inconsistency when a TLB side rebalance occurs? I believe it should,
> but want to confirm.
>
> As for the RLB functionality (i.e., the balance-alb remote to
> local load balance), that is not implemented for IPv6 and this patch is
> not providing an implementation of the RLB logic for IPv6, so I'm
> unclear why you expect it to work, or what the "mismatch Bond6
> specification" is.
>
> To be clear, implementing RLB for IPv6 would include what this
> patch is doing (adjusting the content of NS/NA datagrams), but a
> complete implementation requires additional logic that isn't here, e.g.,
> adding IPv6 logic to the RLB rebalance code, connecting NS/NA
> manipulation to rlb_choose_channel(), and likely other things that don't
> come immediately to mind.
>
> In summary, it sounds to me like the actual bug originally
> reported (with the now-omitted diagram) would be resolved by assigning
> NS/NA datagrams to the curr_active_slave, and supporting RLB for IPv6 is
> a larger project than what's provided by this patch. Am I understanding
> correctly?


Thanks your comment.
For the simplify, I would like to resolve the inconsistent mac at first
by assigning NS/NA datagrams to the curr_active_slave by V6 soon.
Supporting RLB for IPv6, it looks like hard a bit and I wonder if we can
resolve it in another patch?
any comments?


>
> -J
>
>> Suggested-by: Hu Yadi <huyd12@chinatelecom.cn>
>> Reported-by: kernel test robot <lkp@intel.com>
>> Signed-off-by: Sun Shouxin <sunshouxin@chinatelecom.cn>
>> ---
>> drivers/net/bonding/bond_alb.c | 149 +++++++++++++++++++++++++++++++++
>> 1 file changed, 149 insertions(+)
>>
>> diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
>> index 533e476988f2..485e4863a365 100644
>> --- a/drivers/net/bonding/bond_alb.c
>> +++ b/drivers/net/bonding/bond_alb.c
>> @@ -22,6 +22,8 @@
>> #include <asm/byteorder.h>
>> #include <net/bonding.h>
>> #include <net/bond_alb.h>
>> +#include <net/ndisc.h>
>> +#include <net/ip6_checksum.h>
>>
>> static const u8 mac_v6_allmcast[ETH_ALEN + 2] __long_aligned = {
>> 0x33, 0x33, 0x00, 0x00, 0x00, 0x01
>> @@ -1269,6 +1271,137 @@ static int alb_set_mac_address(struct bonding *bond, void *addr)
>> return res;
>> }
>>
>> +/*determine if the packet is NA or NS*/
>> +static bool __alb_determine_nd(struct icmp6hdr *hdr)
>> +{
>> + if (hdr->icmp6_type == NDISC_NEIGHBOUR_ADVERTISEMENT ||
>> + hdr->icmp6_type == NDISC_NEIGHBOUR_SOLICITATION) {
>> + return true;
>> + }
>> +
>> + return false;
>> +}
>> +
>> +static void alb_change_nd_option(struct sk_buff *skb, void *data)
>> +{
>> + struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb);
>> + struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)msg->opt;
>> + struct net_device *dev = skb->dev;
>> + struct icmp6hdr *icmp6h = icmp6_hdr(skb);
>> + struct ipv6hdr *ip6hdr = ipv6_hdr(skb);
>> + u8 *lladdr = NULL;
>> + u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
>> + offsetof(struct nd_msg, opt));
>> +
>> + while (ndoptlen) {
>> + int l;
>> +
>> + switch (nd_opt->nd_opt_type) {
>> + case ND_OPT_SOURCE_LL_ADDR:
>> + case ND_OPT_TARGET_LL_ADDR:
>> + lladdr = ndisc_opt_addr_data(nd_opt, dev);
>> + break;
>> +
>> + default:
>> + lladdr = NULL;
>> + break;
>> + }
>> +
>> + l = nd_opt->nd_opt_len << 3;
>> +
>> + if (ndoptlen < l || l == 0)
>> + return;
>> +
>> + if (lladdr) {
>> + memcpy(lladdr, data, dev->addr_len);
>> + icmp6h->icmp6_cksum = 0;
>> +
>> + icmp6h->icmp6_cksum = csum_ipv6_magic(&ip6hdr->saddr,
>> + &ip6hdr->daddr,
>> + ntohs(ip6hdr->payload_len),
>> + IPPROTO_ICMPV6,
>> + csum_partial(icmp6h,
>> + ntohs(ip6hdr->payload_len), 0));
>> + return;
>> + }
>> + ndoptlen -= l;
>> + nd_opt = ((void *)nd_opt) + l;
>> + }
>> +}
>> +
>> +static u8 *alb_get_lladdr(struct sk_buff *skb)
>> +{
>> + struct nd_msg *msg = (struct nd_msg *)skb_transport_header(skb);
>> + struct nd_opt_hdr *nd_opt = (struct nd_opt_hdr *)msg->opt;
>> + struct net_device *dev = skb->dev;
>> + u8 *lladdr = NULL;
>> + u32 ndoptlen = skb_tail_pointer(skb) - (skb_transport_header(skb) +
>> + offsetof(struct nd_msg, opt));
>> +
>> + while (ndoptlen) {
>> + int l;
>> +
>> + switch (nd_opt->nd_opt_type) {
>> + case ND_OPT_SOURCE_LL_ADDR:
>> + case ND_OPT_TARGET_LL_ADDR:
>> + lladdr = ndisc_opt_addr_data(nd_opt, dev);
>> + break;
>> +
>> + default:
>> + break;
>> + }
>> +
>> + l = nd_opt->nd_opt_len << 3;
>> +
>> + if (ndoptlen < l || l == 0)
>> + return NULL;
>> +
>> + if (lladdr)
>> + return lladdr;
>> +
>> + ndoptlen -= l;
>> + nd_opt = ((void *)nd_opt) + l;
>> + }
>> +
>> + return lladdr;
>> +}
>> +
>> +static void alb_set_nd_option(struct sk_buff *skb, struct bonding *bond,
>> + struct slave *tx_slave)
>> +{
>> + struct ipv6hdr *ip6hdr;
>> + struct icmp6hdr *hdr;
>> +
>> + if (skb->protocol == htons(ETH_P_IPV6)) {
>> + if (tx_slave && tx_slave !=
>> + rcu_access_pointer(bond->curr_active_slave)) {
>> + ip6hdr = ipv6_hdr(skb);
>> + if (ip6hdr->nexthdr == IPPROTO_ICMPV6) {
>> + hdr = icmp6_hdr(skb);
>> + if (__alb_determine_nd(hdr))
>> + alb_change_nd_option(skb, tx_slave->dev->dev_addr);
>> + }
>> + }
>> + }
>> +}
>> +
>> +static bool alb_determine_nd(struct sk_buff *skb, struct bonding *bond)
>> +{
>> + struct ipv6hdr *ip6hdr;
>> + struct icmp6hdr *hdr;
>> +
>> + if (skb->protocol == htons(ETH_P_IPV6)) {
>> + ip6hdr = ipv6_hdr(skb);
>> + if (ip6hdr->nexthdr == IPPROTO_ICMPV6) {
>> + hdr = icmp6_hdr(skb);
>> + if (__alb_determine_nd(hdr))
>> + return true;
>> + }
>> + }
>> +
>> + return false;
>> +}
>> +
>> /************************ exported alb functions ************************/
>>
>> int bond_alb_initialize(struct bonding *bond, int rlb_enabled)
>> @@ -1350,6 +1483,9 @@ struct slave *bond_xmit_tlb_slave_get(struct bonding *bond,
>> switch (skb->protocol) {
>> case htons(ETH_P_IP):
>> case htons(ETH_P_IPV6):
>> + if (alb_determine_nd(skb, bond))
>> + break;
>> +
>> hash_index = bond_xmit_hash(bond, skb);
>> if (bond->params.tlb_dynamic_lb) {
>> tx_slave = tlb_choose_channel(bond,
>> @@ -1446,6 +1582,18 @@ struct slave *bond_xmit_alb_slave_get(struct bonding *bond,
>> break;
>> }
>>
>> + if (alb_determine_nd(skb, bond)) {
>> + u8 *lladdr;
>> +
>> + lladdr = alb_get_lladdr(skb);
>> + if (lladdr) {
>> + if (!bond_slave_has_mac_rx(bond, lladdr)) {
>> + do_tx_balance = false;
>> + break;
>> + }
>> + }
>> + }
>> +
>> hash_start = (char *)&ip6hdr->daddr;
>> hash_size = sizeof(ip6hdr->daddr);
>> break;
>> @@ -1489,6 +1637,7 @@ netdev_tx_t bond_alb_xmit(struct sk_buff *skb, struct net_device *bond_dev)
>> struct slave *tx_slave = NULL;
>>
>> tx_slave = bond_xmit_alb_slave_get(bond, skb);
>> + alb_set_nd_option(skb, bond, tx_slave);
>> return bond_do_alb_xmit(skb, bond, tx_slave);
>> }
>>
>>
>> base-commit: 7a29b11da9651ef6a970e2f6bfd276f053aeb06a
>> --
>> 2.27.0
>>
> ---
> -Jay Vosburgh, jay.vosburgh@canonical.com

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