Linux 4.4 multipath routing with src_ip, dst_ip, src_port, dst_port hash flow-based

linux_4.4_multipath_hash_ipport.patch

--- include/net/ip_fib.h.orig	2016-04-10 11:44:40.342768815 +0700
+++ include/net/ip_fib.h	2016-04-10 15:28:42.217868332 +0700
@@ -331,6 +331,12 @@
 	return jhash_2words(saddr, daddr, fib_multipath_secret) >> 1;
 }
 
+static inline int fib_multipath_hash_ip_port(__be32 saddr, __be32 daddr,
+                                             __be32 ports)
+{
+  return jhash_3words(saddr, daddr, ports, fib_multipath_secret) >> 1;
+}
+
 void fib_select_multipath(struct fib_result *res, int hash);
 void fib_select_path(struct net *net, struct fib_result *res,
 		     struct flowi4 *fl4, int mp_hash);
--- net/ipv4/route.c.orig	2016-04-10 11:53:31.219926652 +0700
+++ net/ipv4/route.c	2016-04-10 15:33:28.934174428 +0700
@@ -113,6 +113,9 @@
 #include <net/secure_seq.h>
 #include <net/ip_tunnels.h>
 #include <net/l3mdev.h>
+#ifdef CONFIG_IP_ROUTE_MULTIPATH
+#include <linux/sctp.h>
+#endif
 
 #define RT_FL_TOS(oldflp4) \
 	((oldflp4)->flowi4_tos & (IPTOS_RT_MASK | RTO_ONLINK))
@@ -1745,8 +1748,59 @@
 
 		if (unlikely(ip_hdr(skb)->protocol == IPPROTO_ICMP))
 			h = ip_multipath_icmp_hash(skb);
-		else
-			h = fib_multipath_hash(saddr, daddr);
+		else {
+	    const struct iphdr *iph = ip_hdr(skb);
+	    unsigned int protooff = skb_network_offset(skb) + ip_hdrlen(skb);
+	    int protocol = iph->protocol;
+      __be32 ports = 0;
+      __be16 *p_port = &ports;
+
+      if (protocol > 0 && !(ntohs(iph->frag_off) & IP_OFFSET)) {
+        switch (protocol) {
+        case IPPROTO_TCP: {
+        	struct tcphdr _tcph;
+        	const struct tcphdr *th;
+
+        	th = skb_header_pointer(skb, protooff, sizeof(_tcph), &_tcph);
+        	if (!th)
+            break;
+
+        	*p_port = th->source;
+        	*(p_port + 1) = th->dest;
+        	break;
+        }
+        case IPPROTO_SCTP: {
+        	sctp_sctphdr_t _sh;
+        	const sctp_sctphdr_t *sh;
+
+        	sh = skb_header_pointer(skb, protooff, sizeof(_sh), &_sh);
+        	if (!sh)
+            break;
+
+        	*p_port = sh->source;
+        	*(p_port + 1) = sh->dest;
+        	break;
+        }
+        case IPPROTO_UDP:
+        case IPPROTO_UDPLITE: {
+        	struct udphdr _udph;
+        	const struct udphdr *uh;
+
+        	uh = skb_header_pointer(skb, protooff, sizeof(_udph), &_udph);
+        	if (!uh)
+        		break;
+
+        	*p_port = uh->source;
+        	*(p_port + 1) = uh->dest;
+        	break;
+        }
+        default:
+          break;
+        }
+      }
+
+			h = fib_multipath_hash_ip_port(saddr, daddr, ports);
+    }
 		fib_select_multipath(res, h);
 	}
 #endif