[PATCH 1/2] bonding: Doesn't support IPv6

[PATCH 1/2] bonding: Doesn't support IPv6

[John]

--- a/drivers/net/bonding/bond_main.c	2011-04-19 11:18:48.000000000 -0700
+++ b/drivers/net/bonding/bond_main.c	2011-10-27 11:26:20.000000000 -0700
@@ -3533,14 +3533,26 @@
  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 =
+			(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;
+	if (skb_headlen(skb) >= 6)
+		return (data->h_dest[5] ^ data->h_source[5]) % count;
+	return 0;
  }

  /*
@@ -3551,22 +3563,39 @@
  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);
+		__be16 *layer4hdr = (__be16 *)((u32 *)iph + iph->ihl);
+		if (iph->ihl * sizeof(u32) + sizeof(__be16) * 2 >
+			skb_headlen(skb) - skb_network_offset(skb)) goto SHORT_HEADER;
  		if (!(iph->frag_off & htons(IP_MF|IP_OFFSET)) &&
-		    (iph->protocol == IPPROTO_TCP ||
-		     iph->protocol == IPPROTO_UDP)) {
+			(iph->protocol == IPPROTO_TCP ||
+			iph->protocol == IPPROTO_UDP)) {
  			layer4_xor = ntohs((*layer4hdr ^ *(layer4hdr + 1)));
  		}
  		return (layer4_xor ^
  			((ntohl(iph->saddr ^ iph->daddr)) & 0xffff)) % count;
-
-	}
-
-	return (data->h_dest[5] ^ data->h_source[5]) % count;
+	} else if (skb->protocol == htons(ETH_P_IPV6)) {
+		struct ipv6hdr *ipv6h = ipv6_hdr(skb);
+		__be16 *layer4hdrv6 = (__be16 *)((u8 *)ipv6h + sizeof(*ipv6h));
+		if (sizeof(struct ipv6hdr) + sizeof(__be16) * 2 >
+			skb_headlen(skb) - skb_network_offset(skb)) goto SHORT_HEADER;
+		if (ipv6h->nexthdr == IPPROTO_TCP || ipv6h->nexthdr == IPPROTO_UDP) {
+			layer4_xor = (*layer4hdrv6 ^ *(layer4hdrv6 + 1));
+		}
+		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;
+	}
+
+	SHORT_HEADER:
+	if (skb_headlen(skb) >= 6)
+		return (data->h_dest[5] ^ data->h_source[5]) % count;
+	return 0;
  }

  /*

Re: [PATCH 1/2] bonding: Doesn't support IPv6

[Michał Mirosław]

2011/10/29 John <linux@8192.net>:
> --- a/drivers/net/bonding/bond_main.c   2011-04-19 11:18:48.000000000 -0700
> +++ b/drivers/net/bonding/bond_main.c   2011-10-27 11:26:20.000000000 -0700
[...]
> +               v6hash = (v6hash >> 16) ^ (v6hash >> 8) ^ v6hash;

This XORs in only 3 of 4 bytes, and assuming count > 256 (its unlikely
you have more than 256 slaves in bond) the most significant byte is
wasted. It should be:

v6hash ^= v6hash >> 16;
v6hash ^= v6hash >> 8;

Same for IPv4 part.

OTOH, if that was your intention, then the description in your mail was wrong.

Best Regards,
Michał Mirosław

Re: [PATCH 1/2] bonding: Doesn't support IPv6

[Eric Dumazet]

Le samedi 29 octobre 2011 à 09:55 +0200, Michał Mirosław a écrit :
> 2011/10/29 John <linux@8192.net>:
> > --- a/drivers/net/bonding/bond_main.c   2011-04-19 11:18:48.000000000 -0700
> > +++ b/drivers/net/bonding/bond_main.c   2011-10-27 11:26:20.000000000 -0700
> [...]
> > +               v6hash = (v6hash >> 16) ^ (v6hash >> 8) ^ v6hash;
> 
> This XORs in only 3 of 4 bytes, and assuming count > 256 (its unlikely
> you have more than 256 slaves in bond) the most significant byte is
> wasted. It should be:
> 
> v6hash ^= v6hash >> 16;
> v6hash ^= v6hash >> 8;
> 
> Same for IPv4 part.
> 
> OTOH, if that was your intention, then the description in your mail was wrong.
> 

Same end result :)

Re: [PATCH 1/2] bonding: Doesn't support IPv6

[Eric Dumazet]

Le samedi 29 octobre 2011 à 10:49 +0200, Eric Dumazet a écrit :
> Le samedi 29 octobre 2011 à 09:55 +0200, Michał Mirosław a écrit :
> > 2011/10/29 John <linux@8192.net>:
> > > --- a/drivers/net/bonding/bond_main.c   2011-04-19 11:18:48.000000000 -0700
> > > +++ b/drivers/net/bonding/bond_main.c   2011-10-27 11:26:20.000000000 -0700
> > [...]
> > > +               v6hash = (v6hash >> 16) ^ (v6hash >> 8) ^ v6hash;
> > 
> > This XORs in only 3 of 4 bytes, and assuming count > 256 (its unlikely
> > you have more than 256 slaves in bond) the most significant byte is
> > wasted. It should be:
> > 
> > v6hash ^= v6hash >> 16;
> > v6hash ^= v6hash >> 8;
> > 
> > Same for IPv4 part.
> > 
> > OTOH, if that was your intention, then the description in your mail was wrong.
> > 
> 
> Same end result :)
> 

Oh well, not exactly, there was a reason for using two different C
instructions ;)

ALso the modulo is expensive...