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
This commit is contained in:
Michael Tuexen 2012-06-12 14:02:38 +00:00
parent b36dcb9a39
commit 3cca425b29
6 changed files with 45 additions and 2 deletions

View File

@ -32,7 +32,7 @@
.\" @(#)ip.4 8.2 (Berkeley) 11/30/93
.\" $FreeBSD$
.\"
.Dd November 14, 2011
.Dd June 12, 2012
.Dt IP 4
.Os
.Sh NAME
@ -286,6 +286,29 @@ cmsg_type = IP_RECVTTL
.\"
.Pp
If the
.Dv IP_RECVTOS
option is enabled on a
.Dv SOCK_DGRAM
socket, the
.Xr recvmsg 2
call will return the
.Tn IP
.Tn TOS
(type of service) field for a
.Tn UDP
datagram.
The msg_control field in the msghdr structure points to a buffer
that contains a cmsghdr structure followed by the
.Tn TOS .
The cmsghdr fields have the following values:
.Bd -literal
cmsg_len = CMSG_LEN(sizeof(u_char))
cmsg_level = IPPROTO_IP
cmsg_type = IP_RECVTOS
.Ed
.\"
.Pp
If the
.Dv IP_RECVIF
option is enabled on a
.Dv SOCK_DGRAM

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@ -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 */

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@ -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;

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@ -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|\

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@ -1684,6 +1684,12 @@ ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
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;
}
}
/*

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@ -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;