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Message-ID: <22560.1335307907@death.nxdomain>
Date: Tue, 24 Apr 2012 15:51:47 -0700
From: Jay Vosburgh <fubar@...ibm.com>
To: John <linux@...2.net>
cc: netdev@...r.kernel.org
Subject: Re: [PATCH V2 1/2] bonding support for IPv6 transmit hashing
John <linux@...2.net> wrote:
In principle, I think this is a good idea, but the patch has
some (mostly style) issues, and does not apply to net-next (you don't
say what tree it is based on).
Can you address the comments noted below, and repost against the
current net-next?
>--- a/drivers/net/bonding/bond_main.c 2012-03-18 16:15:34.000000000 -0700
>+++ b/drivers/net/bonding/bond_main.c 2012-04-14 20:23:26.000000000 -0700
>@@ -3352,56 +3352,87 @@
> /*---------------------------- Hashing Policies -----------------------------*/
>
> /*
>+ * Hash for the output device based upon layer 2 data
>+ */
>+static int bond_xmit_hash_policy_l2(struct sk_buff *skb, int count)
>+{
>+ struct ethhdr *data = (struct ethhdr *)skb->data;
>+
>+ if (skb_headlen(skb) >= 6)
>+ return (data->h_dest[5] ^ data->h_source[5]) % count;
Can skb_headlen ever be less than 6 here? And why >= 6, anyway?
The offset of ->h_source[5] from skb->data is 11.
>+
>+ return 0;
>+}
>+
>+/*
> * Hash for the output device based upon layer 2 and layer 3 data. If
>- * the packet is not IP mimic bond_xmit_hash_policy_l2()
>+ * the packet is not IP, fall back on bond_xmit_hash_policy_l2()
> */
> static int bond_xmit_hash_policy_l23(struct sk_buff *skb, int count)
> {
> struct ethhdr *data = (struct ethhdr *)skb->data;
>- struct iphdr *iph = ip_hdr(skb);
>
>- if (skb->protocol == htons(ETH_P_IP)) {
>+ if (skb->protocol == htons(ETH_P_IP) &&
>+ skb_network_header_len(skb) >= sizeof(struct iphdr)) {
>+ struct iphdr *iph = ip_hdr(skb);
> return ((ntohl(iph->saddr ^ iph->daddr) & 0xffff) ^
> (data->h_dest[5] ^ data->h_source[5])) % count;
>+ } else if (skb->protocol == htons(ETH_P_IPV6) &&
>+ skb_network_header_len(skb) >= sizeof(struct ipv6hdr)) {
>+ struct ipv6hdr *ipv6h = ipv6_hdr(skb);
>+ u32 v6hash =
I personally prefer having variables declared at the head of the
function, not inside inner blocks, but if you're going to do this, there
needs to be a blank line after the declaration.
>+ (ipv6h->saddr.s6_addr32[1] ^ ipv6h->daddr.s6_addr32[1]) ^
>+ (ipv6h->saddr.s6_addr32[2] ^ ipv6h->daddr.s6_addr32[2]) ^
>+ (ipv6h->saddr.s6_addr32[3] ^ ipv6h->daddr.s6_addr32[3]);
>+ v6hash = (v6hash >> 16) ^ (v6hash >> 8) ^ v6hash;
>+ return (v6hash ^ data->h_dest[5] ^ data->h_source[5]) % count;
> }
>
>- return (data->h_dest[5] ^ data->h_source[5]) % count;
>+ return bond_xmit_hash_policy_l2(skb, count);
> }
>
> /*
> * Hash for the output device based upon layer 3 and layer 4 data. If
> * the packet is a frag or not TCP or UDP, just use layer 3 data. If it is
>- * altogether not IP, mimic bond_xmit_hash_policy_l2()
>+ * altogether not IP, fall back on bond_xmit_hash_policy_l2()
> */
> static int bond_xmit_hash_policy_l34(struct sk_buff *skb, int count)
> {
>- struct ethhdr *data = (struct ethhdr *)skb->data;
>- struct iphdr *iph = ip_hdr(skb);
>- __be16 *layer4hdr = (__be16 *)((u32 *)iph + iph->ihl);
>- int layer4_xor = 0;
>+ u32 layer4_xor = 0;
>
> if (skb->protocol == htons(ETH_P_IP)) {
>+ struct iphdr *iph = ip_hdr(skb);
> if (!ip_is_fragment(iph) &&
Blank line after iph declaration.
>- (iph->protocol == IPPROTO_TCP ||
>- iph->protocol == IPPROTO_UDP)) {
>+ (iph->protocol == IPPROTO_TCP ||
>+ iph->protocol == IPPROTO_UDP)) {
>+ __be16 *layer4hdr = (__be16 *)((u32 *)iph + iph->ihl);
Blank line afret the layer4hdr declaration.
>+ if (iph->ihl * sizeof(u32) + sizeof(__be16) * 2 >
>+ skb_headlen(skb) - skb_network_offset(skb)) goto SHORT_HEADER;
The goto needs to be on a separate line.
> layer4_xor = ntohs((*layer4hdr ^ *(layer4hdr + 1)));
>+ } else if (skb_network_header_len(skb) < sizeof(struct iphdr)) {
>+ goto SHORT_HEADER;
> }
> return (layer4_xor ^
> ((ntohl(iph->saddr ^ iph->daddr)) & 0xffff)) % count;
>-
>+ } else if (skb->protocol == htons(ETH_P_IPV6)) {
>+ struct ipv6hdr *ipv6h = ipv6_hdr(skb);
>+ if (ipv6h->nexthdr == IPPROTO_TCP || ipv6h->nexthdr == IPPROTO_UDP) {
Blank line after ipv6h.
>+ __be16 *layer4hdrv6 = (__be16 *)((u8 *)ipv6h + sizeof(struct ipv6hdr));
>+ if (sizeof(struct ipv6hdr) + sizeof(__be16) * 2 >
>+ skb_headlen(skb) - skb_network_offset(skb)) goto SHORT_HEADER;
The goto goes on a separate line.
>+ layer4_xor = (*layer4hdrv6 ^ *(layer4hdrv6 + 1));
>+ } else if (skb_network_header_len(skb) < sizeof(struct ipv6hdr)) {
>+ goto SHORT_HEADER;
>+ }
>+ layer4_xor ^=
>+ (ipv6h->saddr.s6_addr32[1] ^ ipv6h->daddr.s6_addr32[1]) ^
>+ (ipv6h->saddr.s6_addr32[2] ^ ipv6h->daddr.s6_addr32[2]) ^
>+ (ipv6h->saddr.s6_addr32[3] ^ ipv6h->daddr.s6_addr32[3]);
>+ return ((layer4_xor >> 16) ^ (layer4_xor >> 8) ^ layer4_xor) % count;
> }
>
>- return (data->h_dest[5] ^ data->h_source[5]) % count;
>-}
>-
>-/*
>- * Hash for the output device based upon layer 2 data
>- */
>-static int bond_xmit_hash_policy_l2(struct sk_buff *skb, int count)
>-{
>- struct ethhdr *data = (struct ethhdr *)skb->data;
>-
>- return (data->h_dest[5] ^ data->h_source[5]) % count;
>+ SHORT_HEADER:
This label should be lower case, and not indented at all.
-J
>+ return bond_xmit_hash_policy_l2(skb, count);
> }
>
> /*-------------------------- Device entry points ----------------------------*/
---
-Jay Vosburgh, IBM Linux Technology Center, fubar@...ibm.com
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