Subject: Re: [PATCH v8] net: bonding: Add support for IPV6 ns/na to balance-alb/balance-tlb mode

From: Jay Vosburgh <[email-masked]>
Date: Mon, 24 Jan 2022 17:10:23 -0800

Sun Shouxin <[email-masked]> wrote:

>Since ipv6 neighbor solicitation and advertisement messages
>isn't handled gracefully in bond6 driver, we can see packet
>drop due to inconsistency between 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 bridge, the src mac
>might 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.
>
>Suggested-by: Hu Yadi <[email-masked]>
>Acked-by: Jay Vosburgh <[email-masked]>
>Signed-off-by: Sun Shouxin <[email-masked]>
>---
> drivers/net/bonding/bond_alb.c | 37 +++++++++++++++++++++++++++++++++-
> 1 file changed, 36 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
>index 533e476988f2..d4d8670643e9 100644
>--- a/drivers/net/bonding/bond_alb.c
>+++ b/drivers/net/bonding/bond_alb.c
>@@ -1269,6 +1269,34 @@ 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 bool alb_determine_nd(struct sk_buff *skb, struct bonding *bond)
>+{
>+	struct ipv6hdr *ip6hdr;
>+	struct icmp6hdr *hdr;
>+
>+	ip6hdr = ipv6_hdr(skb);
>+	if (ip6hdr->nexthdr == IPPROTO_ICMPV6) {
>+		if (!pskb_may_pull(skb, sizeof(struct ipv6hdr) + sizeof(struct icmp6hdr)))
>+			return true;
>+
>+		hdr = icmp6_hdr(skb);
>+		return __alb_determine_nd(hdr);
>+	}
>+
>+	return false;
>+}
>+
> /************************ exported alb functions ************************/
> 
> int bond_alb_initialize(struct bonding *bond, int rlb_enabled)
>@@ -1348,8 +1376,10 @@ struct slave *bond_xmit_tlb_slave_get(struct bonding *bond,
> 	/* Do not TX balance any multicast or broadcast */
> 	if (!is_multicast_ether_addr(eth_data->h_dest)) {
> 		switch (skb->protocol) {
>-		case htons(ETH_P_IP):
> 		case htons(ETH_P_IPV6):
>+			if (alb_determine_nd(skb, bond))
>+				break;

	I missed this before, but the new expectation is to have a
"fallthrough;" statement when intentionally falling through to the next
case.  See include/linux/compiler_attributes.h.

	That nit aside, this still looks fine to me.

	-J

>+		case htons(ETH_P_IP):
> 			hash_index = bond_xmit_hash(bond, skb);
> 			if (bond->params.tlb_dynamic_lb) {
> 				tx_slave = tlb_choose_channel(bond,
>@@ -1446,6 +1476,11 @@ struct slave *bond_xmit_alb_slave_get(struct bonding *bond,
> 			break;
> 		}
> 
>+		if (alb_determine_nd(skb, bond)) {
>+			do_tx_balance = false;
>+			break;
>+		}
>+
> 		hash_start = (char *)&ip6hdr->daddr;
> 		hash_size = sizeof(ip6hdr->daddr);
> 		break;
>
>base-commit: dd81e1c7d5fb126e5fbc5c9e334d7b3ec29a16a0
>-- 
>2.27.0
>

---
	-Jay Vosburgh, [email-masked]