Add a IP_RECVTOS socket option to receive for received UDP/IPv4

packets a cmsg of type IP_RECVTOS which contains the TOS byte.
Much like IP_RECVTTL does for TTL. This allows to implement a
protocol on top of UDP and implementing ECN.

MFC after: 3 days

5 files changed, 21 insertions, 1 deletions

diff --git a/sys/netinet/in.h b/sys/netinet/in.h
index 56150da..40f5952 100644
--- a/sys/netinet/in.h
+++ b/sys/netinet/in.h
@@ -462,6 +462,7 @@ __END_DECLS
 #define	IP_RECVTTL		65   /* bool; receive IP TTL w/dgram */
 #define	IP_MINTTL		66   /* minimum TTL for packet or drop */
 #define	IP_DONTFRAG		67   /* don't fragment packet */
+#define	IP_RECVTOS		68   /* bool; receive IP TOS w/dgram */
 
 /* IPv4 Source Filter Multicast API [RFC3678] */
 #define	IP_ADD_SOURCE_MEMBERSHIP	70   /* join a source-specific group */
diff --git a/sys/netinet/in_pcb.c b/sys/netinet/in_pcb.c
index e509610..dd1460f 100644
--- a/sys/netinet/in_pcb.c
+++ b/sys/netinet/in_pcb.c
@@ -2295,6 +2295,10 @@ db_print_inpflags(int inp_flags)
 		db_printf("%sINP_DONTFRAG", comma ? ", " : "");
 		comma = 1;
 	}
+	if (inp_flags & INP_RECVTOS) {
+		db_printf("%sINP_RECVTOS", comma ? ", " : "");
+		comma = 1;
+	}
 	if (inp_flags & IN6P_IPV6_V6ONLY) {
 		db_printf("%sIN6P_IPV6_V6ONLY", comma ? ", " : "");
 		comma = 1;
diff --git a/sys/netinet/in_pcb.h b/sys/netinet/in_pcb.h
index c17213b..4945b0f 100644
--- a/sys/netinet/in_pcb.h
+++ b/sys/netinet/in_pcb.h
@@ -509,6 +509,7 @@ void 	inp_4tuple_get(struct inpcb *inp, uint32_t *laddr, uint16_t *lp,
 #define	INP_DONTFRAG		0x00000800 /* don't fragment packet */
 #define	INP_BINDANY		0x00001000 /* allow bind to any address */
 #define	INP_INHASHLIST		0x00002000 /* in_pcbinshash() has been called */
+#define	INP_RECVTOS		0x00004000 /* receive incoming IP TOS */
 #define	IN6P_IPV6_V6ONLY	0x00008000 /* restrict AF_INET6 socket for v6 */
 #define	IN6P_PKTINFO		0x00010000 /* receive IP6 dst and I/F */
 #define	IN6P_HOPLIMIT		0x00020000 /* receive hoplimit */
@@ -528,7 +529,7 @@ void 	inp_4tuple_get(struct inpcb *inp, uint32_t *laddr, uint16_t *lp,
 #define	IN6P_MTU		0x80000000 /* receive path MTU */
 
 #define	INP_CONTROLOPTS		(INP_RECVOPTS|INP_RECVRETOPTS|INP_RECVDSTADDR|\
-				 INP_RECVIF|INP_RECVTTL|\
+				 INP_RECVIF|INP_RECVTTL|INP_RECVTOS|\
 				 IN6P_PKTINFO|IN6P_HOPLIMIT|IN6P_HOPOPTS|\
 				 IN6P_DSTOPTS|IN6P_RTHDR|IN6P_RTHDRDSTOPTS|\
 				 IN6P_TCLASS|IN6P_AUTOFLOWLABEL|IN6P_RFC2292|\
diff --git a/sys/netinet/ip_input.c b/sys/netinet/ip_input.c
index 728b50b..ab78fa2 100644
--- a/sys/netinet/ip_input.c
+++ b/sys/netinet/ip_input.c
@@ -1684,6 +1684,12 @@ makedummy:
 		if (*mp)
 			mp = &(*mp)->m_next;
 	}
+	if (inp->inp_flags & INP_RECVTOS) {
+		*mp = sbcreatecontrol((caddr_t) &ip->ip_tos,
+		    sizeof(u_char), IP_RECVTOS, IPPROTO_IP);
+		if (*mp)
+			mp = &(*mp)->m_next;
+	}
 }
 
 /*
diff --git a/sys/netinet/ip_output.c b/sys/netinet/ip_output.c
index a9008c5..d13c397 100644
--- a/sys/netinet/ip_output.c
+++ b/sys/netinet/ip_output.c
@@ -984,6 +984,7 @@ ip_ctloutput(struct socket *so, struct sockopt *sopt)
 		case IP_FAITH:
 		case IP_ONESBCAST:
 		case IP_DONTFRAG:
+		case IP_RECVTOS:
 			error = sooptcopyin(sopt, &optval, sizeof optval,
 					    sizeof optval);
 			if (error)
@@ -1047,6 +1048,9 @@ ip_ctloutput(struct socket *so, struct sockopt *sopt)
 			case IP_BINDANY:
 				OPTSET(INP_BINDANY);
 				break;
+			case IP_RECVTOS:
+				OPTSET(INP_RECVTOS);
+				break;
 			}
 			break;
 #undef OPTSET
@@ -1156,6 +1160,7 @@ ip_ctloutput(struct socket *so, struct sockopt *sopt)
 		case IP_ONESBCAST:
 		case IP_DONTFRAG:
 		case IP_BINDANY:
+		case IP_RECVTOS:
 			switch (sopt->sopt_name) {
 
 			case IP_TOS:
@@ -1214,6 +1219,9 @@ ip_ctloutput(struct socket *so, struct sockopt *sopt)
 			case IP_BINDANY:
 				optval = OPTBIT(INP_BINDANY);
 				break;
+			case IP_RECVTOS:
+				optval = OPTBIT(INP_RECVTOS);
+				break;
 			}
 			error = sooptcopyout(sopt, &optval, sizeof optval);
 			break;