diff -Nur squid-2.5.STABLE12-20060305/src/cf.data.pre squid-2.5.STABLE12-20060305-zph/src/cf.data.pre
--- squid-2.5.STABLE12-20060305/src/cf.data.pre	2006-03-05 13:20:56.000000000 +0200
+++ squid-2.5.STABLE12-20060305-zph/src/cf.data.pre	2006-03-05 13:28:21.000000000 +0200
@@ -2367,6 +2367,60 @@
 	to off when using this directive in such configurations.
 DOC_END
 
+NAME: zph_tos_local
+TYPE: int
+DEFAULT: 0
+LOC: Config.zph_tos_local
+DOC_START
+	Allows you to select a TOS/Diffserv value to mark local hits. Read above
+	(tcp_outgoing_tos) for details/requirements about TOS.
+	Default: 0 (disabled).
+DOC_END
+
+NAME: zph_tos_peer
+TYPE: int
+DEFAULT: 0
+LOC: Config.zph_tos_peer
+DOC_START
+	Allows you to select a TOS/Diffserv value to mark peer hits. Read above
+	(tcp_outgoing_tos) for details/requirements about TOS.
+	Default: 0 (disabled).
+DOC_END
+
+NAME: zph_tos_parent
+COMMENT: on|off
+TYPE: onoff
+LOC: Config.onoff.zph_tos_parent
+DEFAULT: on
+DOC_START
+	Set this to off if you want only sibling hits to be marked.
+	If set to on (default), parent hits are being marked too.
+DOC_END
+
+NAME: zph_preserve_miss_tos
+COMMENT: on|off
+TYPE: onoff
+LOC: Config.onoff.zph_preserve_miss_tos
+DEFAULT: on
+DOC_START
+	If set to on (default), any HTTP response towards clients will
+	have the TOS value of the response comming from the remote
+	server masked with the value of zph_preserve_miss_tos_mask.
+	For this to work correctly, you will need to patch your linux
+	kernel with the TOS preserving ZPH patch.
+DOC_END
+
+NAME: zph_preserve_miss_tos_mask
+TYPE: int
+DEFAULT: 255
+LOC: Config.zph_preserve_miss_tos_mask
+DOC_START
+	Allows you to mask certain bits in the TOS received from the
+	remote server, before copying the value to the TOS send towards
+	clients.
+	Default: 255 (TOS from server is not changed).
+DOC_END
+
 NAME: tcp_outgoing_address
 TYPE: acl_address
 DEFAULT: none
diff -Nur squid-2.5.STABLE12-20060305/src/client_side.c squid-2.5.STABLE12-20060305-zph/src/client_side.c
--- squid-2.5.STABLE12-20060305/src/client_side.c	2006-03-05 13:20:56.000000000 +0200
+++ squid-2.5.STABLE12-20060305-zph/src/client_side.c	2006-03-05 13:30:26.000000000 +0200
@@ -2008,6 +2008,52 @@
 	return;
     }
     if (http->out.offset == 0) {
+	if (Config.zph_tos_local ||
+               Config.zph_tos_peer ||
+               (Config.onoff.zph_preserve_miss_tos &&
+                Config.zph_preserve_miss_tos_mask) ) {
+           int need_change = 0;
+           int hit = 0;
+           int tos = 0;
+           int tos_old = 0;
+           int tos_len = sizeof(tos_old);
+           int res;
+                       
+           if (Config.zph_tos_local && isTcpHit(http->log_type)) {     /* local hit */
+               hit = 1;
+               tos = Config.zph_tos_local;
+           } else if (Config.zph_tos_peer &&
+               (http->request->hier.code == SIBLING_HIT ||             /* sibling hit */
+               (Config.onoff.zph_tos_parent &&
+               http->request->hier.code == PARENT_HIT))) {             /* parent hit */
+               hit = 1;
+               tos = Config.zph_tos_peer;
+           }
+           if (http->request->flags.proxy_keepalive) {
+               if (getsockopt(fd, IPPROTO_IP, IP_TOS, &tos_old, &tos_len) < 0) {
+                   debug(33, 1) ("ZPH: getsockopt(IP_TOS) on FD %d: %s\n", fd, xstrerror());
+               } else if (hit && tos_old != tos) {     /* HIT: 1-st request, or previous was MISS, */
+                   need_change = 1;                    /* or local/parent hit change */
+               } else if (!hit && (tos_old ||  /* MISS: previous was HIT */
+                                Config.onoff.zph_preserve_miss_tos)) { /* TOS copying is on */
+                       if ( Config.onoff.zph_preserve_miss_tos ) {
+                         tos = (entry->mem_obj != NULL) ?
+                               (entry->mem_obj->recvTOS & Config.zph_preserve_miss_tos_mask):0;
+                       } else tos = 0;
+                   need_change = 1;
+               } 
+           } else if (hit) {                           /* no keepalive */
+               need_change = 1;
+           }
+           if (need_change) {
+               if (!hit) enter_suid(); /* Setting TOS bit6-7 is privilleged */
+               res = setsockopt(fd, IPPROTO_IP, IP_TOS, &tos, sizeof(tos));
+               if (!hit) leave_suid(); /* Setting bit5-7 is privilleged */
+               if ( res < 0)
+                   debug(33, 1) ("ZPH: setsockopt(IP_TOS) on FD %d: %s\n",
+                                         fd, xstrerror());
+           }
+	}
 	rep = http->reply = clientBuildReply(http, buf, size);
 	if (rep) {
 	    aclCheck_t *ch;
diff -Nur squid-2.5.STABLE12-20060305/src/http.c squid-2.5.STABLE12-20060305-zph/src/http.c
--- squid-2.5.STABLE12-20060305/src/http.c	2005-10-18 18:09:56.000000000 +0300
+++ squid-2.5.STABLE12-20060305-zph/src/http.c	2006-03-05 13:28:21.000000000 +0200
@@ -1072,6 +1072,51 @@
     peer *p = httpState->peer;
     CWCB *sendHeaderDone;
     int fd = httpState->fd;
+    int tos, tos_len;
+    
+	/* ZPH patch starts here (M.Stavrev 25-05-2005)
+	 * Retrieve connection peer's TOS value (which its SYN_ACK TCP segment
+	 * was encapsulated into an IP packet)
+	 */
+    if ( entry && entry->mem_obj ) { // Is this check necessary ? Seems not, but
+				 // have no time to investigate further.
+	    entry->mem_obj->recvTOS = 0;
+	    tos = 1;
+	    tos_len = sizeof(tos);
+	 	if ( setsockopt(fd,SOL_IP, IP_RECVTOS, &tos, tos_len) == 0 ) {
+		    unsigned char buf[128];
+		    int len = 128;
+		    if (getsockopt(fd, SOL_IP, IP_PKTOPTIONS, buf, &len) == 0)
+		    {
+		    	/* Parse the PKTOPTIONS structure to locate the TOS data message
+		    	 * prepared in the kernel by the ZPH incoming TCP TOS preserving
+		    	 * patch. In 99,99% the TOS should be located at buf[12], but
+		    	 * let's do it the right way.
+		    	 */
+		    	unsigned char * p = buf;
+		    	while ( p-buf < len ) {
+		    		struct cmsghdr * o = (struct cmsghdr*)p;
+		    		if ( o->cmsg_len <= 0 || o->cmsg_len > 52 )
+		    		   break;
+		    		if ( o->cmsg_level == SOL_IP && o->cmsg_type == IP_TOS ) {
+	    			   entry->mem_obj->recvTOS = (unsigned char)(*(int*)
+			    	   						(p + sizeof(struct cmsghdr)));
+				       debug(11, 5) ("ZPH: Incomming TOS=%d on FD %d\n",
+				       			entry->mem_obj->recvTOS, fd );
+			    	   break;
+		    		}
+		    		p += o->cmsg_len;
+		    	}
+		    } else {
+		    	debug(11, 5) ("ZPH: getsockopt(IP_PKTOPTIONS) on FD %d: %s\n",
+		    				 fd, xstrerror());
+		    }
+		} else {
+	    	debug(11, 5) ("ZPH: setsockopt(IP_RECVTOS) on FD %d: %s\n",
+	    					 fd, xstrerror());
+		}
+    }
+	/* ZPH patch ends here */
 
     debug(11, 5) ("httpSendRequest: FD %d: httpState %p.\n", fd, httpState);
 
diff -Nur squid-2.5.STABLE12-20060305/src/structs.h squid-2.5.STABLE12-20060305-zph/src/structs.h
--- squid-2.5.STABLE12-20060305/src/structs.h	2006-03-05 13:20:56.000000000 +0200
+++ squid-2.5.STABLE12-20060305-zph/src/structs.h	2006-03-05 13:28:21.000000000 +0200
@@ -613,6 +613,8 @@
 	int accel_uses_host_header;
 	int accel_no_pmtu_disc;
 	int global_internal_static;
+	int zph_tos_parent;
+	int zph_preserve_miss_tos;
     } onoff;
     acl *aclList;
     struct {
@@ -715,6 +717,9 @@
     char *store_dir_select_algorithm;
     int sleep_after_fork;	/* microseconds */
     external_acl *externalAclHelperList;
+    int zph_tos_local;
+    int zph_tos_peer;
+    int zph_preserve_miss_tos_mask;
 };
 
 struct _SquidConfig2 {
@@ -1530,6 +1535,7 @@
     unsigned int chksum;
 #endif
     const char *vary_headers;
+    unsigned char recvTOS; /* ZPH patch - stores remote server's TOS */
 };
 
 struct _StoreEntry {