diff -Nur linux-2.6.26.3/include/net/inet_sock.h linux-2.6.26.3-zph/include/net/inet_sock.h
--- linux-2.6.26.3/include/net/inet_sock.h	2008-08-20 21:11:37.000000000 +0300
+++ linux-2.6.26.3-zph/include/net/inet_sock.h	2008-08-21 16:51:59.000000000 +0300
@@ -157,6 +157,7 @@
 	__be32			mc_addr;
 	struct ip_mc_socklist __rcu	*mc_list;
 	struct inet_cork_full	cork;
+	__u16			zph_tos;	/* ZPH TOS received on connect */
 };
 
 #define IPCORK_OPT	1	/* ip-options has been held in ipcork.opt */
diff -Nur linux-2.6.26.3/net/ipv4/ip_sockglue.c linux-2.6.26.3-zph/net/ipv4/ip_sockglue.c
--- linux-2.6.26.3/net/ipv4/ip_sockglue.c	2008-08-20 21:11:37.000000000 +0300
+++ linux-2.6.26.3-zph/net/ipv4/ip_sockglue.c	2008-08-21 16:54:21.000000000 +0300
@@ -1126,6 +1126,10 @@
 			int hlim = inet->mc_ttl;
 			put_cmsg(&msg, SOL_IP, IP_TTL, sizeof(hlim), &hlim);
 		}
+		if (inet->cmsg_flags&IP_CMSG_TOS) {
+			int hlim = inet->zph_tos & 0xFF;
+			put_cmsg(&msg, SOL_IP, IP_TOS, sizeof(hlim), &hlim);
+		}
 		len -= msg.msg_controllen;
 		return put_user(len, optlen);
 	}
diff -Nur linux-2.6.26.3/net/ipv4/tcp_input.c linux-2.6.26.3-zph/net/ipv4/tcp_input.c
--- linux-2.6.26.3/net/ipv4/tcp_input.c	2008-08-20 21:11:37.000000000 +0300
+++ linux-2.6.26.3-zph/net/ipv4/tcp_input.c	2008-08-21 17:06:55.000000000 +0300
@@ -3900,6 +3900,8 @@
 	struct tcp_sock *tp = tcp_sk(sk);
 	int eaten = -1;
 	bool fragstolen = false;
+	struct inet_sock *inet = inet_sk(sk);
+	struct iphdr *iph = ip_hdr(skb);
 
 	if (TCP_SKB_CB(skb)->seq == TCP_SKB_CB(skb)->end_seq)
 		goto drop;
@@ -3914,6 +3916,12 @@
 					     4 - tp->rx_opt.tstamp_ok);
 	}
 
+	// ZPH: Copy the TOS value of the first data ACK segment
+	// received from the remote peer.
+	if (0==(inet->zph_tos & 0x8000)) {
+		inet->zph_tos = 0x8000 | iph->tos;
+	}
+
 	/*  Queue data for delivery to the user.
 	 *  Packets in sequence go to the receive queue.
 	 *  Out of sequence packets to the out_of_order_queue.
@@ -4915,5 +4923,7 @@
 	struct inet_connection_sock *icsk = inet_csk(sk);
 	struct tcp_sock *tp = tcp_sk(sk);
+	struct inet_sock *inet = inet_sk(sk);
+	struct iphdr *iph = ip_hdr(skb);
 	struct tcp_fastopen_cookie foc = { .len = -1 };
 	int saved_clamp = tp->rx_opt.mss_clamp;
 
@@ -4973,6 +4983,15 @@
 
 		TCP_ECN_rcv_synack(tp, th);
 
+		/* ZPH:
+		 * Copy TOS field from the SYNACK packet to zph_tos field of the af_inet
+		 * member of sock structure. This value shall be overwritten when the first
+		 * data segment is received from the peer. However, for completeness in
+		 * case the socket TOS is being asked befor that, we copy the TOS value from
+		 * the SYNACK packet.
+		 */
+		inet->zph_tos = iph->tos;
+
 		tcp_init_wl(tp, TCP_SKB_CB(skb)->seq);
 		tcp_ack(sk, skb, FLAG_SLOWPATH);