Subject: [PATCH V2 1/2] bonding support for IPv6 transmit hashing

From: John <[email-masked]>
Date: Tue, 17 Apr 2012 17:27:57 -0700

--- 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;
+
+	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 =
+			(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) &&
-		    (iph->protocol == IPPROTO_TCP ||
-		     iph->protocol == IPPROTO_UDP)) {
+			(iph->protocol == IPPROTO_TCP ||
+			iph->protocol == IPPROTO_UDP)) {
+			__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;
  			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) {
+			__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;
+			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:
+	return bond_xmit_hash_policy_l2(skb, count);
  }

  /*-------------------------- Device entry points ----------------------------*/